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-rw-r--r--html/edit/001-editor.mu.html397
-rw-r--r--html/edit/002-typing.mu.html909
-rw-r--r--html/edit/003-shortcuts.mu.html2499
-rw-r--r--html/edit/004-programming-environment.mu.html639
-rw-r--r--html/edit/005-sandbox.mu.html1141
-rw-r--r--html/edit/006-sandbox-copy.mu.html217
-rw-r--r--html/edit/007-sandbox-delete.mu.html335
-rw-r--r--html/edit/008-sandbox-edit.mu.html279
-rw-r--r--html/edit/009-sandbox-test.mu.html219
-rw-r--r--html/edit/010-sandbox-trace.mu.html247
-rw-r--r--html/edit/011-errors.mu.html757
-rw-r--r--html/edit/012-editor-undo.mu.html1633
12 files changed, 4642 insertions, 4630 deletions
diff --git a/html/edit/001-editor.mu.html b/html/edit/001-editor.mu.html
index fc380b8d..1355cf75 100644
--- a/html/edit/001-editor.mu.html
+++ b/html/edit/001-editor.mu.html
@@ -15,16 +15,17 @@ body { font-size: 12pt; font-family: monospace; color: #eeeeee; background-color
 a { text-decoration: none; }
 a:hover { text-decoration: underline; }
 * { font-size: 12pt; font-size: 1em; }
-.muData { color: #ffff00; }
-.muControl { color: #c0a020; }
+.muRecipe { color: #ff8700; }
+.muScenario { color: #00af00; }
 .Special { color: #c00000; }
+.Conceal { color: #4e4e4e; }
 .Delimiter { color: #800080; }
 .SalientComment { color: #00ffff; }
 .Constant { color: #00a0a0; }
 .LineNr { color: #444444; }
 .Comment { color: #9090ff; }
-.muRecipe { color: #ff8700; }
-.muScenario { color: #00af00; }
+.muControl { color: #c0a020; }
+.muData { color: #ffff00; }
 -->
 </style>
 
@@ -80,13 +81,13 @@ if ('onhashchange' in window) {
 <span id="L19" class="LineNr"> 19 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
 <span id="L20" class="LineNr"> 20 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> <span class="Constant">[abc]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L21" class="LineNr"> 21 </span>  run [
-<span id="L22" class="LineNr"> 22 </span>    <a href='001-editor.mu.html#L123'>render</a> <a href='../081print.mu.html#L4'>screen</a>, e
+<span id="L22" class="LineNr"> 22 </span>  <span class="Conceal">¦</span> <a href='001-editor.mu.html#L123'>render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L23" class="LineNr"> 23 </span>  ]
 <span id="L24" class="LineNr"> 24 </span>  screen-should-contain [
-<span id="L25" class="LineNr"> 25 </span>    <span class="Comment"># top line of screen reserved for menu</span>
-<span id="L26" class="LineNr"> 26 </span>   <span class="Constant"> .          .</span>
-<span id="L27" class="LineNr"> 27 </span>   <span class="Constant"> .abc       .</span>
-<span id="L28" class="LineNr"> 28 </span>   <span class="Constant"> .          .</span>
+<span id="L25" class="LineNr"> 25 </span>  <span class="Conceal">¦</span> <span class="Comment"># top line of screen reserved for menu</span>
+<span id="L26" class="LineNr"> 26 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L27" class="LineNr"> 27 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L28" class="LineNr"> 28 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L29" class="LineNr"> 29 </span>  ]
 <span id="L30" class="LineNr"> 30 </span>]
 <span id="L31" class="LineNr"> 31 </span>
@@ -142,14 +143,14 @@ if ('onhashchange' in window) {
 <span id="L81" class="LineNr"> 81 </span>  <span class="Comment"># now we can start appending the rest, character by character</span>
 <span id="L82" class="LineNr"> 82 </span>  curr:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
 <span id="L83" class="LineNr"> 83 </span>  <span class="Delimiter">{</span>
-<span id="L84" class="LineNr"> 84 </span>    done?:bool <span class="Special">&lt;-</span> greater-or-equal idx, len
-<span id="L85" class="LineNr"> 85 </span>    <span class="muControl">break-if</span> done?
-<span id="L86" class="LineNr"> 86 </span>    c:char <span class="Special">&lt;-</span> index *text, idx
-<span id="L87" class="LineNr"> 87 </span>    insert c, curr
-<span id="L88" class="LineNr"> 88 </span>    <span class="Comment"># next iter</span>
-<span id="L89" class="LineNr"> 89 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
-<span id="L90" class="LineNr"> 90 </span>    idx <span class="Special">&lt;-</span> add idx,<span class="Constant"> 1</span>
-<span id="L91" class="LineNr"> 91 </span>    <span class="muControl">loop</span>
+<span id="L84" class="LineNr"> 84 </span>  <span class="Conceal">¦</span> done?:bool <span class="Special">&lt;-</span> greater-or-equal idx, len
+<span id="L85" class="LineNr"> 85 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
+<span id="L86" class="LineNr"> 86 </span>  <span class="Conceal">¦</span> c:char <span class="Special">&lt;-</span> index *text, idx
+<span id="L87" class="LineNr"> 87 </span>  <span class="Conceal">¦</span> insert c, curr
+<span id="L88" class="LineNr"> 88 </span>  <span class="Conceal">¦</span> <span class="Comment"># next iter</span>
+<span id="L89" class="LineNr"> 89 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L90" class="LineNr"> 90 </span>  <span class="Conceal">¦</span> idx <span class="Special">&lt;-</span> add idx,<span class="Constant"> 1</span>
+<span id="L91" class="LineNr"> 91 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L92" class="LineNr"> 92 </span>  <span class="Delimiter">}</span>
 <span id="L93" class="LineNr"> 93 </span>]
 <span id="L94" class="LineNr"> 94 </span>
@@ -157,24 +158,24 @@ if ('onhashchange' in window) {
 <span id="L96" class="LineNr"> 96 </span>  <span class="Constant">local-scope</span>
 <span id="L97" class="LineNr"> 97 </span>  assume-screen <span class="Constant">5/width</span>, <span class="Constant">3/height</span>
 <span id="L98" class="LineNr"> 98 </span>  run [
-<span id="L99" class="LineNr"> 99 </span>    e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> <span class="Constant">0/data</span>, <span class="Constant">2/left</span>, <span class="Constant">5/right</span>
-<span id="L100" class="LineNr">100 </span>    2:editor/<span class="Special">raw</span> <span class="Special">&lt;-</span> copy *e
+<span id="L99" class="LineNr"> 99 </span>  <span class="Conceal">¦</span> e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> <span class="Constant">0/data</span>, <span class="Constant">2/left</span>, <span class="Constant">5/right</span>
+<span id="L100" class="LineNr">100 </span>  <span class="Conceal">¦</span> 2:editor/<span class="Special">raw</span> <span class="Special">&lt;-</span> copy *e
 <span id="L101" class="LineNr">101 </span>  ]
 <span id="L102" class="LineNr">102 </span>  memory-should-contain [
-<span id="L103" class="LineNr">103 </span>    <span class="Comment"># 2 (data) &lt;- just the § sentinel</span>
-<span id="L104" class="LineNr">104 </span>    <span class="Comment"># 3 (top of screen) &lt;- the § sentinel</span>
-<span id="L105" class="LineNr">105 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># bottom-of-screen; null since text fits on screen</span>
-<span id="L106" class="LineNr">106 </span>    <span class="Comment"># 5 (before cursor) &lt;- the § sentinel</span>
-<span id="L107" class="LineNr">107 </span>   <span class="Constant"> 6</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>  <span class="Comment"># left</span>
-<span id="L108" class="LineNr">108 </span>   <span class="Constant"> 7</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>  <span class="Comment"># right  (inclusive)</span>
-<span id="L109" class="LineNr">109 </span>   <span class="Constant"> 8</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># bottom (not set until render)</span>
-<span id="L110" class="LineNr">110 </span>   <span class="Constant"> 9</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># cursor row</span>
-<span id="L111" class="LineNr">111 </span>   <span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>  <span class="Comment"># cursor column</span>
+<span id="L103" class="LineNr">103 </span>  <span class="Conceal">¦</span> <span class="Comment"># 2 (data) &lt;- just the § sentinel</span>
+<span id="L104" class="LineNr">104 </span>  <span class="Conceal">¦</span> <span class="Comment"># 3 (top of screen) &lt;- the § sentinel</span>
+<span id="L105" class="LineNr">105 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># bottom-of-screen; null since text fits on screen</span>
+<span id="L106" class="LineNr">106 </span>  <span class="Conceal">¦</span> <span class="Comment"># 5 (before cursor) &lt;- the § sentinel</span>
+<span id="L107" class="LineNr">107 </span>  <span class="Conceal">¦</span><span class="Constant"> 6</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>  <span class="Comment"># left</span>
+<span id="L108" class="LineNr">108 </span>  <span class="Conceal">¦</span><span class="Constant"> 7</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>  <span class="Comment"># right  (inclusive)</span>
+<span id="L109" class="LineNr">109 </span>  <span class="Conceal">¦</span><span class="Constant"> 8</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># bottom (not set until render)</span>
+<span id="L110" class="LineNr">110 </span>  <span class="Conceal">¦</span><span class="Constant"> 9</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># cursor row</span>
+<span id="L111" class="LineNr">111 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>  <span class="Comment"># cursor column</span>
 <span id="L112" class="LineNr">112 </span>  ]
 <span id="L113" class="LineNr">113 </span>  screen-should-contain [
-<span id="L114" class="LineNr">114 </span>   <span class="Constant"> .     .</span>
-<span id="L115" class="LineNr">115 </span>   <span class="Constant"> .     .</span>
-<span id="L116" class="LineNr">116 </span>   <span class="Constant"> .     .</span>
+<span id="L114" class="LineNr">114 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L115" class="LineNr">115 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L116" class="LineNr">116 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
 <span id="L117" class="LineNr">117 </span>  ]
 <span id="L118" class="LineNr">118 </span>]
 <span id="L119" class="LineNr">119 </span>
@@ -202,78 +203,78 @@ if ('onhashchange' in window) {
 <span id="L141" class="LineNr">141 </span>  before-cursor:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
 <span id="L142" class="LineNr">142 </span>  <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, column
 <span id="L143" class="LineNr">143 </span>  <span class="Delimiter">{</span>
-<span id="L144" class="LineNr">144 </span><span class="Constant">    +next-character</span>
-<span id="L145" class="LineNr">145 </span>    <span class="muControl">break-unless</span> curr
-<span id="L146" class="LineNr">146 </span>    off-screen?:bool <span class="Special">&lt;-</span> greater-or-equal row, <a href='../081print.mu.html#L594'>screen-height</a>
-<span id="L147" class="LineNr">147 </span>    <span class="muControl">break-if</span> off-screen?
-<span id="L148" class="LineNr">148 </span>    <span class="Comment"># update editor.before-cursor</span>
-<span id="L149" class="LineNr">149 </span>    <span class="Comment"># Doing so at the start of each iteration ensures it stays one step behind</span>
-<span id="L150" class="LineNr">150 </span>    <span class="Comment"># the current character.</span>
-<span id="L151" class="LineNr">151 </span>    <span class="Delimiter">{</span>
-<span id="L152" class="LineNr">152 </span>      at-cursor-row?:bool <span class="Special">&lt;-</span> equal row, cursor-row
-<span id="L153" class="LineNr">153 </span>      <span class="muControl">break-unless</span> at-cursor-row?
-<span id="L154" class="LineNr">154 </span>      at-cursor?:bool <span class="Special">&lt;-</span> equal column, cursor-column
-<span id="L155" class="LineNr">155 </span>      <span class="muControl">break-unless</span> at-cursor?
-<span id="L156" class="LineNr">156 </span>      before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
-<span id="L157" class="LineNr">157 </span>    <span class="Delimiter">}</span>
-<span id="L158" class="LineNr">158 </span>    c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
-<span id="L159" class="LineNr">159 </span><span class="Constant">    &lt;character-c-received&gt;</span>
-<span id="L160" class="LineNr">160 </span>    <span class="Delimiter">{</span>
-<span id="L161" class="LineNr">161 </span>      <span class="Comment"># newline? move to left rather than 0</span>
-<span id="L162" class="LineNr">162 </span>      newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
-<span id="L163" class="LineNr">163 </span>      <span class="muControl">break-unless</span> newline?
-<span id="L164" class="LineNr">164 </span>      <span class="Comment"># adjust cursor if necessary</span>
-<span id="L165" class="LineNr">165 </span>      <span class="Delimiter">{</span>
-<span id="L166" class="LineNr">166 </span>        at-cursor-row?:bool <span class="Special">&lt;-</span> equal row, cursor-row
-<span id="L167" class="LineNr">167 </span>        <span class="muControl">break-unless</span> at-cursor-row?
-<span id="L168" class="LineNr">168 </span>        left-of-cursor?:bool <span class="Special">&lt;-</span> lesser-than column, cursor-column
-<span id="L169" class="LineNr">169 </span>        <span class="muControl">break-unless</span> left-of-cursor?
-<span id="L170" class="LineNr">170 </span>        cursor-column <span class="Special">&lt;-</span> copy column
-<span id="L171" class="LineNr">171 </span>        before-cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> curr
-<span id="L172" class="LineNr">172 </span>      <span class="Delimiter">}</span>
-<span id="L173" class="LineNr">173 </span>      <span class="Comment"># clear rest of line in this window</span>
-<span id="L174" class="LineNr">174 </span>      <a href='../081print.mu.html#L408'>clear-line-until</a> <a href='../081print.mu.html#L4'>screen</a>, right
-<span id="L175" class="LineNr">175 </span>      <span class="Comment"># skip to next line</span>
-<span id="L176" class="LineNr">176 </span>      row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
-<span id="L177" class="LineNr">177 </span>      column <span class="Special">&lt;-</span> copy left
-<span id="L178" class="LineNr">178 </span>      <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, column
-<span id="L179" class="LineNr">179 </span>      curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
-<span id="L180" class="LineNr">180 </span>      <a href='../065duplex_list.mu.html#L36'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> <a href='../065duplex_list.mu.html#L36'>prev</a>
-<span id="L181" class="LineNr">181 </span>      <span class="muControl">loop</span> <span class="Constant">+next-character</span>
-<span id="L182" class="LineNr">182 </span>    <span class="Delimiter">}</span>
-<span id="L183" class="LineNr">183 </span>    <span class="Delimiter">{</span>
-<span id="L184" class="LineNr">184 </span>      <span class="Comment"># at right? wrap. even if there's only one more letter left; we need</span>
-<span id="L185" class="LineNr">185 </span>      <span class="Comment"># room for clicking on the cursor after it.</span>
-<span id="L186" class="LineNr">186 </span>      at-right?:bool <span class="Special">&lt;-</span> equal column, right
-<span id="L187" class="LineNr">187 </span>      <span class="muControl">break-unless</span> at-right?
-<span id="L188" class="LineNr">188 </span>      <span class="Comment"># print wrap icon</span>
-<span id="L189" class="LineNr">189 </span>      wrap-icon:char <span class="Special">&lt;-</span> copy <span class="Constant">8617/loop-back-to-left</span>
-<span id="L190" class="LineNr">190 </span>      print <a href='../081print.mu.html#L4'>screen</a>, wrap-icon, <span class="Constant">245/grey</span>
-<span id="L191" class="LineNr">191 </span>      column <span class="Special">&lt;-</span> copy left
-<span id="L192" class="LineNr">192 </span>      row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
-<span id="L193" class="LineNr">193 </span>      <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, column
-<span id="L194" class="LineNr">194 </span>      <span class="Comment"># don't increment curr</span>
-<span id="L195" class="LineNr">195 </span>      <span class="muControl">loop</span> <span class="Constant">+next-character</span>
-<span id="L196" class="LineNr">196 </span>    <span class="Delimiter">}</span>
-<span id="L197" class="LineNr">197 </span>    print <a href='../081print.mu.html#L4'>screen</a>, c, color
-<span id="L198" class="LineNr">198 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
-<span id="L199" class="LineNr">199 </span>    <a href='../065duplex_list.mu.html#L36'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> <a href='../065duplex_list.mu.html#L36'>prev</a>
-<span id="L200" class="LineNr">200 </span>    column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
-<span id="L201" class="LineNr">201 </span>    <span class="muControl">loop</span>
+<span id="L144" class="LineNr">144 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> +next-character</span>
+<span id="L145" class="LineNr">145 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> curr
+<span id="L146" class="LineNr">146 </span>  <span class="Conceal">¦</span> off-screen?:bool <span class="Special">&lt;-</span> greater-or-equal row, <a href='../081print.mu.html#L594'>screen-height</a>
+<span id="L147" class="LineNr">147 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> off-screen?
+<span id="L148" class="LineNr">148 </span>  <span class="Conceal">¦</span> <span class="Comment"># update editor.before-cursor</span>
+<span id="L149" class="LineNr">149 </span>  <span class="Conceal">¦</span> <span class="Comment"># Doing so at the start of each iteration ensures it stays one step behind</span>
+<span id="L150" class="LineNr">150 </span>  <span class="Conceal">¦</span> <span class="Comment"># the current character.</span>
+<span id="L151" class="LineNr">151 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L152" class="LineNr">152 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-cursor-row?:bool <span class="Special">&lt;-</span> equal row, cursor-row
+<span id="L153" class="LineNr">153 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-cursor-row?
+<span id="L154" class="LineNr">154 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-cursor?:bool <span class="Special">&lt;-</span> equal column, cursor-column
+<span id="L155" class="LineNr">155 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-cursor?
+<span id="L156" class="LineNr">156 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L157" class="LineNr">157 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L158" class="LineNr">158 </span>  <span class="Conceal">¦</span> c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
+<span id="L159" class="LineNr">159 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;character-c-received&gt;</span>
+<span id="L160" class="LineNr">160 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L161" class="LineNr">161 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># newline? move to left rather than 0</span>
+<span id="L162" class="LineNr">162 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
+<span id="L163" class="LineNr">163 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> newline?
+<span id="L164" class="LineNr">164 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># adjust cursor if necessary</span>
+<span id="L165" class="LineNr">165 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L166" class="LineNr">166 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-cursor-row?:bool <span class="Special">&lt;-</span> equal row, cursor-row
+<span id="L167" class="LineNr">167 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-cursor-row?
+<span id="L168" class="LineNr">168 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> left-of-cursor?:bool <span class="Special">&lt;-</span> lesser-than column, cursor-column
+<span id="L169" class="LineNr">169 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> left-of-cursor?
+<span id="L170" class="LineNr">170 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> copy column
+<span id="L171" class="LineNr">171 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> curr
+<span id="L172" class="LineNr">172 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L173" class="LineNr">173 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># clear rest of line in this window</span>
+<span id="L174" class="LineNr">174 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../081print.mu.html#L408'>clear-line-until</a> <a href='../081print.mu.html#L4'>screen</a>, right
+<span id="L175" class="LineNr">175 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># skip to next line</span>
+<span id="L176" class="LineNr">176 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
+<span id="L177" class="LineNr">177 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> copy left
+<span id="L178" class="LineNr">178 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, column
+<span id="L179" class="LineNr">179 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L180" class="LineNr">180 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L181" class="LineNr">181 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-character</span>
+<span id="L182" class="LineNr">182 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L183" class="LineNr">183 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L184" class="LineNr">184 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># at right? wrap. even if there's only one more letter left; we need</span>
+<span id="L185" class="LineNr">185 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># room for clicking on the cursor after it.</span>
+<span id="L186" class="LineNr">186 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-right?:bool <span class="Special">&lt;-</span> equal column, right
+<span id="L187" class="LineNr">187 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-right?
+<span id="L188" class="LineNr">188 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># print wrap icon</span>
+<span id="L189" class="LineNr">189 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> wrap-icon:char <span class="Special">&lt;-</span> copy <span class="Constant">8617/loop-back-to-left</span>
+<span id="L190" class="LineNr">190 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, wrap-icon, <span class="Constant">245/grey</span>
+<span id="L191" class="LineNr">191 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> copy left
+<span id="L192" class="LineNr">192 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
+<span id="L193" class="LineNr">193 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, column
+<span id="L194" class="LineNr">194 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># don't increment curr</span>
+<span id="L195" class="LineNr">195 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-character</span>
+<span id="L196" class="LineNr">196 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L197" class="LineNr">197 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, c, color
+<span id="L198" class="LineNr">198 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L199" class="LineNr">199 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L200" class="LineNr">200 </span>  <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
+<span id="L201" class="LineNr">201 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L202" class="LineNr">202 </span>  <span class="Delimiter">}</span>
 <span id="L203" class="LineNr">203 </span>  <span class="Comment"># save first character off-screen</span>
 <span id="L204" class="LineNr">204 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">bottom-of-screen:offset</span>, curr
 <span id="L205" class="LineNr">205 </span>  <span class="Comment"># is cursor to the right of the last line? move to end</span>
 <span id="L206" class="LineNr">206 </span>  <span class="Delimiter">{</span>
-<span id="L207" class="LineNr">207 </span>    at-cursor-row?:bool <span class="Special">&lt;-</span> equal row, cursor-row
-<span id="L208" class="LineNr">208 </span>    cursor-outside-line?:bool <span class="Special">&lt;-</span> lesser-or-equal column, cursor-column
-<span id="L209" class="LineNr">209 </span>    before-cursor-on-same-line?:bool <span class="Special">&lt;-</span> and at-cursor-row?, cursor-outside-line?
-<span id="L210" class="LineNr">210 </span>    above-cursor-row?:bool <span class="Special">&lt;-</span> lesser-than row, cursor-row
-<span id="L211" class="LineNr">211 </span>    before-cursor?:bool <span class="Special">&lt;-</span> or before-cursor-on-same-line?, above-cursor-row?
-<span id="L212" class="LineNr">212 </span>    <span class="muControl">break-unless</span> before-cursor?
-<span id="L213" class="LineNr">213 </span>    cursor-row <span class="Special">&lt;-</span> copy row
-<span id="L214" class="LineNr">214 </span>    cursor-column <span class="Special">&lt;-</span> copy column
-<span id="L215" class="LineNr">215 </span>    before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L207" class="LineNr">207 </span>  <span class="Conceal">¦</span> at-cursor-row?:bool <span class="Special">&lt;-</span> equal row, cursor-row
+<span id="L208" class="LineNr">208 </span>  <span class="Conceal">¦</span> cursor-outside-line?:bool <span class="Special">&lt;-</span> lesser-or-equal column, cursor-column
+<span id="L209" class="LineNr">209 </span>  <span class="Conceal">¦</span> before-cursor-on-same-line?:bool <span class="Special">&lt;-</span> and at-cursor-row?, cursor-outside-line?
+<span id="L210" class="LineNr">210 </span>  <span class="Conceal">¦</span> above-cursor-row?:bool <span class="Special">&lt;-</span> lesser-than row, cursor-row
+<span id="L211" class="LineNr">211 </span>  <span class="Conceal">¦</span> before-cursor?:bool <span class="Special">&lt;-</span> or before-cursor-on-same-line?, above-cursor-row?
+<span id="L212" class="LineNr">212 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> before-cursor?
+<span id="L213" class="LineNr">213 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> copy row
+<span id="L214" class="LineNr">214 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> copy column
+<span id="L215" class="LineNr">215 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
 <span id="L216" class="LineNr">216 </span>  <span class="Delimiter">}</span>
 <span id="L217" class="LineNr">217 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">bottom:offset</span>, row
 <span id="L218" class="LineNr">218 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
@@ -287,9 +288,9 @@ if ('onhashchange' in window) {
 <span id="L226" class="LineNr">226 </span>  <span class="Constant">load-ingredients</span>
 <span id="L227" class="LineNr">227 </span>  <span class="Comment"># if it's the real screen, use the optimized primitive</span>
 <span id="L228" class="LineNr">228 </span>  <span class="Delimiter">{</span>
-<span id="L229" class="LineNr">229 </span>    <span class="muControl">break-if</span> <a href='../081print.mu.html#L4'>screen</a>
-<span id="L230" class="LineNr">230 </span>    clear-display-from row, column, left, right
-<span id="L231" class="LineNr">231 </span>    <span class="muControl">return</span>
+<span id="L229" class="LineNr">229 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> <a href='../081print.mu.html#L4'>screen</a>
+<span id="L230" class="LineNr">230 </span>  <span class="Conceal">¦</span> clear-display-from row, column, left, right
+<span id="L231" class="LineNr">231 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
 <span id="L232" class="LineNr">232 </span>  <span class="Delimiter">}</span>
 <span id="L233" class="LineNr">233 </span>  <span class="Comment"># if not, go the slower route</span>
 <span id="L234" class="LineNr">234 </span>  <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, column
@@ -304,12 +305,12 @@ if ('onhashchange' in window) {
 <span id="L243" class="LineNr">243 </span>  <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, left
 <span id="L244" class="LineNr">244 </span>  <a href='../081print.mu.html#L594'>screen-height</a>:num <span class="Special">&lt;-</span> <a href='../081print.mu.html#L594'>screen-height</a> <a href='../081print.mu.html#L4'>screen</a>
 <span id="L245" class="LineNr">245 </span>  <span class="Delimiter">{</span>
-<span id="L246" class="LineNr">246 </span>    at-bottom-of-screen?:bool <span class="Special">&lt;-</span> greater-or-equal row, <a href='../081print.mu.html#L594'>screen-height</a>
-<span id="L247" class="LineNr">247 </span>    <span class="muControl">break-if</span> at-bottom-of-screen?
-<span id="L248" class="LineNr">248 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, left
-<span id="L249" class="LineNr">249 </span>    <a href='../081print.mu.html#L408'>clear-line-until</a> <a href='../081print.mu.html#L4'>screen</a>, right
-<span id="L250" class="LineNr">250 </span>    row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
-<span id="L251" class="LineNr">251 </span>    <span class="muControl">loop</span>
+<span id="L246" class="LineNr">246 </span>  <span class="Conceal">¦</span> at-bottom-of-screen?:bool <span class="Special">&lt;-</span> greater-or-equal row, <a href='../081print.mu.html#L594'>screen-height</a>
+<span id="L247" class="LineNr">247 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-bottom-of-screen?
+<span id="L248" class="LineNr">248 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, left
+<span id="L249" class="LineNr">249 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L408'>clear-line-until</a> <a href='../081print.mu.html#L4'>screen</a>, right
+<span id="L250" class="LineNr">250 </span>  <span class="Conceal">¦</span> row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
+<span id="L251" class="LineNr">251 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L252" class="LineNr">252 </span>  <span class="Delimiter">}</span>
 <span id="L253" class="LineNr">253 </span>]
 <span id="L254" class="LineNr">254 </span>
@@ -320,13 +321,13 @@ if ('onhashchange' in window) {
 <span id="L259" class="LineNr">259 </span><span class="Constant">def]</span>
 <span id="L260" class="LineNr">260 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
 <span id="L261" class="LineNr">261 </span>  run [
-<span id="L262" class="LineNr">262 </span>    <a href='001-editor.mu.html#L123'>render</a> <a href='../081print.mu.html#L4'>screen</a>, e
+<span id="L262" class="LineNr">262 </span>  <span class="Conceal">¦</span> <a href='001-editor.mu.html#L123'>render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L263" class="LineNr">263 </span>  ]
 <span id="L264" class="LineNr">264 </span>  screen-should-contain [
-<span id="L265" class="LineNr">265 </span>   <span class="Constant"> .     .</span>
-<span id="L266" class="LineNr">266 </span>   <span class="Constant"> .abc  .</span>
-<span id="L267" class="LineNr">267 </span>   <span class="Constant"> .def  .</span>
-<span id="L268" class="LineNr">268 </span>   <span class="Constant"> .     .</span>
+<span id="L265" class="LineNr">265 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L266" class="LineNr">266 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc  .</span>
+<span id="L267" class="LineNr">267 </span>  <span class="Conceal">¦</span><span class="Constant"> .def  .</span>
+<span id="L268" class="LineNr">268 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
 <span id="L269" class="LineNr">269 </span>  ]
 <span id="L270" class="LineNr">270 </span>]
 <span id="L271" class="LineNr">271 </span>
@@ -335,12 +336,12 @@ if ('onhashchange' in window) {
 <span id="L274" class="LineNr">274 </span>  assume-screen <span class="Constant">5/width</span>, <span class="Constant">5/height</span>
 <span id="L275" class="LineNr">275 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> <span class="Constant">[abc]</span>, <span class="Constant">1/left</span>, <span class="Constant">5/right</span>
 <span id="L276" class="LineNr">276 </span>  run [
-<span id="L277" class="LineNr">277 </span>    <a href='001-editor.mu.html#L123'>render</a> <a href='../081print.mu.html#L4'>screen</a>, e
+<span id="L277" class="LineNr">277 </span>  <span class="Conceal">¦</span> <a href='001-editor.mu.html#L123'>render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L278" class="LineNr">278 </span>  ]
 <span id="L279" class="LineNr">279 </span>  screen-should-contain [
-<span id="L280" class="LineNr">280 </span>   <span class="Constant"> .     .</span>
-<span id="L281" class="LineNr">281 </span>   <span class="Constant"> . abc .</span>
-<span id="L282" class="LineNr">282 </span>   <span class="Constant"> .     .</span>
+<span id="L280" class="LineNr">280 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L281" class="LineNr">281 </span>  <span class="Conceal">¦</span><span class="Constant"> . abc .</span>
+<span id="L282" class="LineNr">282 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
 <span id="L283" class="LineNr">283 </span>  ]
 <span id="L284" class="LineNr">284 </span>]
 <span id="L285" class="LineNr">285 </span>
@@ -351,13 +352,13 @@ if ('onhashchange' in window) {
 <span id="L290" class="LineNr">290 </span><span class="Constant">def]</span>
 <span id="L291" class="LineNr">291 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">1/left</span>, <span class="Constant">5/right</span>
 <span id="L292" class="LineNr">292 </span>  run [
-<span id="L293" class="LineNr">293 </span>    <a href='001-editor.mu.html#L123'>render</a> <a href='../081print.mu.html#L4'>screen</a>, e
+<span id="L293" class="LineNr">293 </span>  <span class="Conceal">¦</span> <a href='001-editor.mu.html#L123'>render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L294" class="LineNr">294 </span>  ]
 <span id="L295" class="LineNr">295 </span>  screen-should-contain [
-<span id="L296" class="LineNr">296 </span>   <span class="Constant"> .     .</span>
-<span id="L297" class="LineNr">297 </span>   <span class="Constant"> . abc .</span>
-<span id="L298" class="LineNr">298 </span>   <span class="Constant"> . def .</span>
-<span id="L299" class="LineNr">299 </span>   <span class="Constant"> .     .</span>
+<span id="L296" class="LineNr">296 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L297" class="LineNr">297 </span>  <span class="Conceal">¦</span><span class="Constant"> . abc .</span>
+<span id="L298" class="LineNr">298 </span>  <span class="Conceal">¦</span><span class="Constant"> . def .</span>
+<span id="L299" class="LineNr">299 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
 <span id="L300" class="LineNr">300 </span>  ]
 <span id="L301" class="LineNr">301 </span>]
 <span id="L302" class="LineNr">302 </span>
@@ -366,19 +367,19 @@ if ('onhashchange' in window) {
 <span id="L305" class="LineNr">305 </span>  assume-screen <span class="Constant">5/width</span>, <span class="Constant">5/height</span>
 <span id="L306" class="LineNr">306 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> <span class="Constant">[abc def]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
 <span id="L307" class="LineNr">307 </span>  run [
-<span id="L308" class="LineNr">308 </span>    <a href='001-editor.mu.html#L123'>render</a> <a href='../081print.mu.html#L4'>screen</a>, e
+<span id="L308" class="LineNr">308 </span>  <span class="Conceal">¦</span> <a href='001-editor.mu.html#L123'>render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L309" class="LineNr">309 </span>  ]
 <span id="L310" class="LineNr">310 </span>  screen-should-contain [
-<span id="L311" class="LineNr">311 </span>   <span class="Constant"> .     .</span>
-<span id="L312" class="LineNr">312 </span>   <span class="Constant"> .abc ↩.</span>
-<span id="L313" class="LineNr">313 </span>   <span class="Constant"> .def  .</span>
-<span id="L314" class="LineNr">314 </span>   <span class="Constant"> .     .</span>
+<span id="L311" class="LineNr">311 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L312" class="LineNr">312 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc ↩.</span>
+<span id="L313" class="LineNr">313 </span>  <span class="Conceal">¦</span><span class="Constant"> .def  .</span>
+<span id="L314" class="LineNr">314 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
 <span id="L315" class="LineNr">315 </span>  ]
 <span id="L316" class="LineNr">316 </span>  screen-should-contain-in-color <span class="Constant">245/grey</span> [
-<span id="L317" class="LineNr">317 </span>   <span class="Constant"> .     .</span>
-<span id="L318" class="LineNr">318 </span>   <span class="Constant"> .    ↩.</span>
-<span id="L319" class="LineNr">319 </span>   <span class="Constant"> .     .</span>
-<span id="L320" class="LineNr">320 </span>   <span class="Constant"> .     .</span>
+<span id="L317" class="LineNr">317 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L318" class="LineNr">318 </span>  <span class="Conceal">¦</span><span class="Constant"> .    ↩.</span>
+<span id="L319" class="LineNr">319 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L320" class="LineNr">320 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
 <span id="L321" class="LineNr">321 </span>  ]
 <span id="L322" class="LineNr">322 </span>]
 <span id="L323" class="LineNr">323 </span>
@@ -387,21 +388,21 @@ if ('onhashchange' in window) {
 <span id="L326" class="LineNr">326 </span>  assume-screen <span class="Constant">5/width</span>, <span class="Constant">5/height</span>
 <span id="L327" class="LineNr">327 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> <span class="Constant">[abcde]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
 <span id="L328" class="LineNr">328 </span>  run [
-<span id="L329" class="LineNr">329 </span>    <a href='001-editor.mu.html#L123'>render</a> <a href='../081print.mu.html#L4'>screen</a>, e
+<span id="L329" class="LineNr">329 </span>  <span class="Conceal">¦</span> <a href='001-editor.mu.html#L123'>render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L330" class="LineNr">330 </span>  ]
 <span id="L331" class="LineNr">331 </span>  <span class="Comment"># still wrap, even though the line would fit. We need room to click on the</span>
 <span id="L332" class="LineNr">332 </span>  <span class="Comment"># end of the line</span>
 <span id="L333" class="LineNr">333 </span>  screen-should-contain [
-<span id="L334" class="LineNr">334 </span>   <span class="Constant"> .     .</span>
-<span id="L335" class="LineNr">335 </span><span class="Constant">    .abcd↩.</span>
-<span id="L336" class="LineNr">336 </span>   <span class="Constant"> .e    .</span>
-<span id="L337" class="LineNr">337 </span>   <span class="Constant"> .     .</span>
+<span id="L334" class="LineNr">334 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L335" class="LineNr">335 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .abcd↩.</span>
+<span id="L336" class="LineNr">336 </span>  <span class="Conceal">¦</span><span class="Constant"> .e    .</span>
+<span id="L337" class="LineNr">337 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
 <span id="L338" class="LineNr">338 </span>  ]
 <span id="L339" class="LineNr">339 </span>  screen-should-contain-in-color <span class="Constant">245/grey</span> [
-<span id="L340" class="LineNr">340 </span>   <span class="Constant"> .     .</span>
-<span id="L341" class="LineNr">341 </span>   <span class="Constant"> .    ↩.</span>
-<span id="L342" class="LineNr">342 </span>   <span class="Constant"> .     .</span>
-<span id="L343" class="LineNr">343 </span>   <span class="Constant"> .     .</span>
+<span id="L340" class="LineNr">340 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L341" class="LineNr">341 </span>  <span class="Conceal">¦</span><span class="Constant"> .    ↩.</span>
+<span id="L342" class="LineNr">342 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L343" class="LineNr">343 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
 <span id="L344" class="LineNr">344 </span>  ]
 <span id="L345" class="LineNr">345 </span>]
 <span id="L346" class="LineNr">346 </span>
@@ -410,18 +411,18 @@ if ('onhashchange' in window) {
 <span id="L349" class="LineNr">349 </span>  assume-screen <span class="Constant">5/width</span>, <span class="Constant">5/height</span>
 <span id="L350" class="LineNr">350 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> <span class="Constant">[]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
 <span id="L351" class="LineNr">351 </span>  run [
-<span id="L352" class="LineNr">352 </span>    <a href='001-editor.mu.html#L123'>render</a> <a href='../081print.mu.html#L4'>screen</a>, e
-<span id="L353" class="LineNr">353 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L354" class="LineNr">354 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L352" class="LineNr">352 </span>  <span class="Conceal">¦</span> <a href='001-editor.mu.html#L123'>render</a> <a href='../081print.mu.html#L4'>screen</a>, e
+<span id="L353" class="LineNr">353 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L354" class="LineNr">354 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L355" class="LineNr">355 </span>  ]
 <span id="L356" class="LineNr">356 </span>  screen-should-contain [
-<span id="L357" class="LineNr">357 </span>   <span class="Constant"> .     .</span>
-<span id="L358" class="LineNr">358 </span>   <span class="Constant"> .     .</span>
-<span id="L359" class="LineNr">359 </span>   <span class="Constant"> .     .</span>
+<span id="L357" class="LineNr">357 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L358" class="LineNr">358 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L359" class="LineNr">359 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
 <span id="L360" class="LineNr">360 </span>  ]
 <span id="L361" class="LineNr">361 </span>  memory-should-contain [
-<span id="L362" class="LineNr">362 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># cursor row</span>
-<span id="L363" class="LineNr">363 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># cursor column</span>
+<span id="L362" class="LineNr">362 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># cursor row</span>
+<span id="L363" class="LineNr">363 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># cursor column</span>
 <span id="L364" class="LineNr">364 </span>  ]
 <span id="L365" class="LineNr">365 </span>]
 <span id="L366" class="LineNr">366 </span>
@@ -435,28 +436,28 @@ if ('onhashchange' in window) {
 <span id="L374" class="LineNr">374 </span><span class="Constant">f]</span>
 <span id="L375" class="LineNr">375 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
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+<span id="L377" class="LineNr">377 </span>  <span class="Conceal">¦</span> <a href='001-editor.mu.html#L123'>render</a> <a href='../081print.mu.html#L4'>screen</a>, e
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-<span id="L380" class="LineNr">380 </span>   <span class="Constant"> .     .</span>
-<span id="L381" class="LineNr">381 </span>   <span class="Constant"> .abc  .</span>
-<span id="L382" class="LineNr">382 </span>   <span class="Constant"> .# de .</span>
-<span id="L383" class="LineNr">383 </span>   <span class="Constant"> .f    .</span>
-<span id="L384" class="LineNr">384 </span>   <span class="Constant"> .     .</span>
+<span id="L380" class="LineNr">380 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L381" class="LineNr">381 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc  .</span>
+<span id="L382" class="LineNr">382 </span>  <span class="Conceal">¦</span><span class="Constant"> .# de .</span>
+<span id="L383" class="LineNr">383 </span>  <span class="Conceal">¦</span><span class="Constant"> .f    .</span>
+<span id="L384" class="LineNr">384 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
 <span id="L385" class="LineNr">385 </span>  ]
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-<span id="L387" class="LineNr">387 </span>   <span class="Constant"> .     .</span>
-<span id="L388" class="LineNr">388 </span>   <span class="Constant"> .     .</span>
-<span id="L389" class="LineNr">389 </span>   <span class="Constant"> .# de .</span>
-<span id="L390" class="LineNr">390 </span>   <span class="Constant"> .     .</span>
-<span id="L391" class="LineNr">391 </span>   <span class="Constant"> .     .</span>
+<span id="L387" class="LineNr">387 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L388" class="LineNr">388 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L389" class="LineNr">389 </span>  <span class="Conceal">¦</span><span class="Constant"> .# de .</span>
+<span id="L390" class="LineNr">390 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L391" class="LineNr">391 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
 <span id="L392" class="LineNr">392 </span>  ]
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-<span id="L394" class="LineNr">394 </span>   <span class="Constant"> .     .</span>
-<span id="L395" class="LineNr">395 </span>   <span class="Constant"> .abc  .</span>
-<span id="L396" class="LineNr">396 </span>   <span class="Constant"> .     .</span>
-<span id="L397" class="LineNr">397 </span>   <span class="Constant"> .f    .</span>
-<span id="L398" class="LineNr">398 </span>   <span class="Constant"> .     .</span>
+<span id="L394" class="LineNr">394 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L395" class="LineNr">395 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc  .</span>
+<span id="L396" class="LineNr">396 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L397" class="LineNr">397 </span>  <span class="Conceal">¦</span><span class="Constant"> .f    .</span>
+<span id="L398" class="LineNr">398 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
 <span id="L399" class="LineNr">399 </span>  ]
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 <span id="L401" class="LineNr">401 </span>
@@ -471,39 +472,39 @@ if ('onhashchange' in window) {
 <span id="L410" class="LineNr">410 </span>  color-is-white?:bool <span class="Special">&lt;-</span> equal color, <span class="Constant">7/white</span>
 <span id="L411" class="LineNr">411 </span>  <span class="Comment"># if color is white and next character is '#', switch color to blue</span>
 <span id="L412" class="LineNr">412 </span>  <span class="Delimiter">{</span>
-<span id="L413" class="LineNr">413 </span>    <span class="muControl">break-unless</span> color-is-white?
-<span id="L414" class="LineNr">414 </span>    starting-comment?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">35/#</span>
-<span id="L415" class="LineNr">415 </span>    <span class="muControl">break-unless</span> starting-comment?
-<span id="L416" class="LineNr">416 </span>    trace<span class="Constant"> 90</span>, <span class="Constant">[app]</span>, <span class="Constant">[switch color back to blue]</span>
-<span id="L417" class="LineNr">417 </span>    color <span class="Special">&lt;-</span> copy <span class="Constant">12/lightblue</span>
-<span id="L418" class="LineNr">418 </span>    <span class="muControl">jump</span> <span class="Constant">+exit</span>
+<span id="L413" class="LineNr">413 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> color-is-white?
+<span id="L414" class="LineNr">414 </span>  <span class="Conceal">¦</span> starting-comment?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">35/#</span>
+<span id="L415" class="LineNr">415 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> starting-comment?
+<span id="L416" class="LineNr">416 </span>  <span class="Conceal">¦</span> trace<span class="Constant"> 90</span>, <span class="Constant">[app]</span>, <span class="Constant">[switch color back to blue]</span>
+<span id="L417" class="LineNr">417 </span>  <span class="Conceal">¦</span> color <span class="Special">&lt;-</span> copy <span class="Constant">12/lightblue</span>
+<span id="L418" class="LineNr">418 </span>  <span class="Conceal">¦</span> <span class="muControl">jump</span> <span class="Constant">+exit</span>
 <span id="L419" class="LineNr">419 </span>  <span class="Delimiter">}</span>
 <span id="L420" class="LineNr">420 </span>  <span class="Comment"># if color is blue and next character is newline, switch color to white</span>
 <span id="L421" class="LineNr">421 </span>  <span class="Delimiter">{</span>
-<span id="L422" class="LineNr">422 </span>    color-is-blue?:bool <span class="Special">&lt;-</span> equal color, <span class="Constant">12/lightblue</span>
-<span id="L423" class="LineNr">423 </span>    <span class="muControl">break-unless</span> color-is-blue?
-<span id="L424" class="LineNr">424 </span>    ending-comment?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
-<span id="L425" class="LineNr">425 </span>    <span class="muControl">break-unless</span> ending-comment?
-<span id="L426" class="LineNr">426 </span>    trace<span class="Constant"> 90</span>, <span class="Constant">[app]</span>, <span class="Constant">[switch color back to white]</span>
-<span id="L427" class="LineNr">427 </span>    color <span class="Special">&lt;-</span> copy <span class="Constant">7/white</span>
-<span id="L428" class="LineNr">428 </span>    <span class="muControl">jump</span> <span class="Constant">+exit</span>
+<span id="L422" class="LineNr">422 </span>  <span class="Conceal">¦</span> color-is-blue?:bool <span class="Special">&lt;-</span> equal color, <span class="Constant">12/lightblue</span>
+<span id="L423" class="LineNr">423 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> color-is-blue?
+<span id="L424" class="LineNr">424 </span>  <span class="Conceal">¦</span> ending-comment?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
+<span id="L425" class="LineNr">425 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> ending-comment?
+<span id="L426" class="LineNr">426 </span>  <span class="Conceal">¦</span> trace<span class="Constant"> 90</span>, <span class="Constant">[app]</span>, <span class="Constant">[switch color back to white]</span>
+<span id="L427" class="LineNr">427 </span>  <span class="Conceal">¦</span> color <span class="Special">&lt;-</span> copy <span class="Constant">7/white</span>
+<span id="L428" class="LineNr">428 </span>  <span class="Conceal">¦</span> <span class="muControl">jump</span> <span class="Constant">+exit</span>
 <span id="L429" class="LineNr">429 </span>  <span class="Delimiter">}</span>
 <span id="L430" class="LineNr">430 </span>  <span class="Comment"># if color is white (no comments) and next character is '&lt;', switch color to red</span>
 <span id="L431" class="LineNr">431 </span>  <span class="Delimiter">{</span>
-<span id="L432" class="LineNr">432 </span>    <span class="muControl">break-unless</span> color-is-white?
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-<span id="L434" class="LineNr">434 </span>    <span class="muControl">break-unless</span> starting-assignment?
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-<span id="L436" class="LineNr">436 </span>    <span class="muControl">jump</span> <span class="Constant">+exit</span>
+<span id="L432" class="LineNr">432 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> color-is-white?
+<span id="L433" class="LineNr">433 </span>  <span class="Conceal">¦</span> starting-assignment?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">60/&lt;</span>
+<span id="L434" class="LineNr">434 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> starting-assignment?
+<span id="L435" class="LineNr">435 </span>  <span class="Conceal">¦</span> color <span class="Special">&lt;-</span> copy <span class="Constant">1/red</span>
+<span id="L436" class="LineNr">436 </span>  <span class="Conceal">¦</span> <span class="muControl">jump</span> <span class="Constant">+exit</span>
 <span id="L437" class="LineNr">437 </span>  <span class="Delimiter">}</span>
 <span id="L438" class="LineNr">438 </span>  <span class="Comment"># if color is red and next character is space, switch color to white</span>
 <span id="L439" class="LineNr">439 </span>  <span class="Delimiter">{</span>
-<span id="L440" class="LineNr">440 </span>    color-is-red?:bool <span class="Special">&lt;-</span> equal color, <span class="Constant">1/red</span>
-<span id="L441" class="LineNr">441 </span>    <span class="muControl">break-unless</span> color-is-red?
-<span id="L442" class="LineNr">442 </span>    ending-assignment?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">32/space</span>
-<span id="L443" class="LineNr">443 </span>    <span class="muControl">break-unless</span> ending-assignment?
-<span id="L444" class="LineNr">444 </span>    color <span class="Special">&lt;-</span> copy <span class="Constant">7/white</span>
-<span id="L445" class="LineNr">445 </span>    <span class="muControl">jump</span> <span class="Constant">+exit</span>
+<span id="L440" class="LineNr">440 </span>  <span class="Conceal">¦</span> color-is-red?:bool <span class="Special">&lt;-</span> equal color, <span class="Constant">1/red</span>
+<span id="L441" class="LineNr">441 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> color-is-red?
+<span id="L442" class="LineNr">442 </span>  <span class="Conceal">¦</span> ending-assignment?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">32/space</span>
+<span id="L443" class="LineNr">443 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> ending-assignment?
+<span id="L444" class="LineNr">444 </span>  <span class="Conceal">¦</span> color <span class="Special">&lt;-</span> copy <span class="Constant">7/white</span>
+<span id="L445" class="LineNr">445 </span>  <span class="Conceal">¦</span> <span class="muControl">jump</span> <span class="Constant">+exit</span>
 <span id="L446" class="LineNr">446 </span>  <span class="Delimiter">}</span>
 <span id="L447" class="LineNr">447 </span>  <span class="Comment"># otherwise no change</span>
 <span id="L448" class="LineNr">448 </span><span class="Constant">  +exit</span>
@@ -518,21 +519,21 @@ if ('onhashchange' in window) {
 <span id="L457" class="LineNr">457 </span><span class="Constant">f]</span>
 <span id="L458" class="LineNr">458 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">8/right</span>
 <span id="L459" class="LineNr">459 </span>  run [
-<span id="L460" class="LineNr">460 </span>    <a href='001-editor.mu.html#L123'>render</a> <a href='../081print.mu.html#L4'>screen</a>, e
+<span id="L460" class="LineNr">460 </span>  <span class="Conceal">¦</span> <a href='001-editor.mu.html#L123'>render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L461" class="LineNr">461 </span>  ]
 <span id="L462" class="LineNr">462 </span>  screen-should-contain [
-<span id="L463" class="LineNr">463 </span>   <span class="Constant"> .        .</span>
-<span id="L464" class="LineNr">464 </span>   <span class="Constant"> .abc     .</span>
-<span id="L465" class="LineNr">465 </span>   <span class="Constant"> .d &lt;- e  .</span>
-<span id="L466" class="LineNr">466 </span>   <span class="Constant"> .f       .</span>
-<span id="L467" class="LineNr">467 </span>   <span class="Constant"> .        .</span>
+<span id="L463" class="LineNr">463 </span>  <span class="Conceal">¦</span><span class="Constant"> .        .</span>
+<span id="L464" class="LineNr">464 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc     .</span>
+<span id="L465" class="LineNr">465 </span>  <span class="Conceal">¦</span><span class="Constant"> .d &lt;- e  .</span>
+<span id="L466" class="LineNr">466 </span>  <span class="Conceal">¦</span><span class="Constant"> .f       .</span>
+<span id="L467" class="LineNr">467 </span>  <span class="Conceal">¦</span><span class="Constant"> .        .</span>
 <span id="L468" class="LineNr">468 </span>  ]
 <span id="L469" class="LineNr">469 </span>  screen-should-contain-in-color <span class="Constant">1/red</span>, [
-<span id="L470" class="LineNr">470 </span>   <span class="Constant"> .        .</span>
-<span id="L471" class="LineNr">471 </span>   <span class="Constant"> .        .</span>
-<span id="L472" class="LineNr">472 </span>   <span class="Constant"> .  &lt;-    .</span>
-<span id="L473" class="LineNr">473 </span>   <span class="Constant"> .        .</span>
-<span id="L474" class="LineNr">474 </span>   <span class="Constant"> .        .</span>
+<span id="L470" class="LineNr">470 </span>  <span class="Conceal">¦</span><span class="Constant"> .        .</span>
+<span id="L471" class="LineNr">471 </span>  <span class="Conceal">¦</span><span class="Constant"> .        .</span>
+<span id="L472" class="LineNr">472 </span>  <span class="Conceal">¦</span><span class="Constant"> .  &lt;-    .</span>
+<span id="L473" class="LineNr">473 </span>  <span class="Conceal">¦</span><span class="Constant"> .        .</span>
+<span id="L474" class="LineNr">474 </span>  <span class="Conceal">¦</span><span class="Constant"> .        .</span>
 <span id="L475" class="LineNr">475 </span>  ]
 <span id="L476" class="LineNr">476 </span>]
 </pre>
diff --git a/html/edit/002-typing.mu.html b/html/edit/002-typing.mu.html
index 71244ddb..3c8b89ae 100644
--- a/html/edit/002-typing.mu.html
+++ b/html/edit/002-typing.mu.html
@@ -15,16 +15,17 @@ body { font-size: 12pt; font-family: monospace; color: #eeeeee; background-color
 a { text-decoration: none; }
 a:hover { text-decoration: underline; }
 * { font-size: 12pt; font-size: 1em; }
-.Delimiter { color: #800080; }
-.muControl { color: #c0a020; }
+.muRecipe { color: #ff8700; }
+.muScenario { color: #00af00; }
 .Special { color: #c00000; }
-.muData { color: #ffff00; }
+.Conceal { color: #4e4e4e; }
+.Delimiter { color: #800080; }
 .SalientComment { color: #00ffff; }
 .Constant { color: #00a0a0; }
 .LineNr { color: #444444; }
 .Comment { color: #9090ff; }
-.muRecipe { color: #ff8700; }
-.muScenario { color: #00af00; }
+.muControl { color: #c0a020; }
+.muData { color: #ffff00; }
 -->
 </style>
 
@@ -76,32 +77,32 @@ if ('onhashchange' in window) {
 <span id="L15" class="LineNr">  15 </span>  <span class="Constant">local-scope</span>
 <span id="L16" class="LineNr">  16 </span>  <span class="Constant">load-ingredients</span>
 <span id="L17" class="LineNr">  17 </span>  <span class="Delimiter">{</span>
-<span id="L18" class="LineNr">  18 </span>    <span class="Comment"># looping over each (keyboard or touch) event as it occurs</span>
-<span id="L19" class="LineNr">  19 </span><span class="Constant">    +next-event</span>
-<span id="L20" class="LineNr">  20 </span>    cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
-<span id="L21" class="LineNr">  21 </span>    cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
-<span id="L22" class="LineNr">  22 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, cursor-row, cursor-column
-<span id="L23" class="LineNr">  23 </span>    e:<a href='../084console.mu.html#L4'>event</a>, found?:bool, quit?:bool, <a href='../084console.mu.html#L23'>console</a> <span class="Special">&lt;-</span> <a href='../084console.mu.html#L35'>read-event</a> <a href='../084console.mu.html#L23'>console</a>
-<span id="L24" class="LineNr">  24 </span>    <span class="muControl">loop-unless</span> found?
-<span id="L25" class="LineNr">  25 </span>    <span class="muControl">break-if</span> quit?  <span class="Comment"># only in tests</span>
-<span id="L26" class="LineNr">  26 </span>    trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[next-event]</span>
-<span id="L27" class="LineNr">  27 </span>    <span class="Comment"># 'touch' event</span>
-<span id="L28" class="LineNr">  28 </span>    t:<a href='../084console.mu.html#L12'>touch-event</a>, is-touch?:bool <span class="Special">&lt;-</span> maybe-convert e, <span class="Constant">touch:variant</span>
-<span id="L29" class="LineNr">  29 </span>    <span class="Delimiter">{</span>
-<span id="L30" class="LineNr">  30 </span>      <span class="muControl">break-unless</span> is-touch?
-<span id="L31" class="LineNr">  31 </span>      <a href='002-typing.mu.html#L48'>move-cursor-in-editor</a> <a href='../081print.mu.html#L4'>screen</a>, editor, t
-<span id="L32" class="LineNr">  32 </span>      <span class="muControl">loop</span> <span class="Constant">+next-event</span>
-<span id="L33" class="LineNr">  33 </span>    <span class="Delimiter">}</span>
-<span id="L34" class="LineNr">  34 </span>    <span class="Comment"># keyboard events</span>
-<span id="L35" class="LineNr">  35 </span>    <span class="Delimiter">{</span>
-<span id="L36" class="LineNr">  36 </span>      <span class="muControl">break-if</span> is-touch?
-<span id="L37" class="LineNr">  37 </span>      go-render?:bool <span class="Special">&lt;-</span> <a href='002-typing.mu.html#L164'>handle-keyboard-event</a> <a href='../081print.mu.html#L4'>screen</a>, editor, e
-<span id="L38" class="LineNr">  38 </span>      <span class="Delimiter">{</span>
-<span id="L39" class="LineNr">  39 </span>        <span class="muControl">break-unless</span> go-render?
-<span id="L40" class="LineNr">  40 </span>        <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, editor
-<span id="L41" class="LineNr">  41 </span>      <span class="Delimiter">}</span>
-<span id="L42" class="LineNr">  42 </span>    <span class="Delimiter">}</span>
-<span id="L43" class="LineNr">  43 </span>    <span class="muControl">loop</span>
+<span id="L18" class="LineNr">  18 </span>  <span class="Conceal">¦</span> <span class="Comment"># looping over each (keyboard or touch) event as it occurs</span>
+<span id="L19" class="LineNr">  19 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> +next-event</span>
+<span id="L20" class="LineNr">  20 </span>  <span class="Conceal">¦</span> cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
+<span id="L21" class="LineNr">  21 </span>  <span class="Conceal">¦</span> cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
+<span id="L22" class="LineNr">  22 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, cursor-row, cursor-column
+<span id="L23" class="LineNr">  23 </span>  <span class="Conceal">¦</span> e:<a href='../084console.mu.html#L4'>event</a>, found?:bool, quit?:bool, <a href='../084console.mu.html#L23'>console</a> <span class="Special">&lt;-</span> <a href='../084console.mu.html#L35'>read-event</a> <a href='../084console.mu.html#L23'>console</a>
+<span id="L24" class="LineNr">  24 </span>  <span class="Conceal">¦</span> <span class="muControl">loop-unless</span> found?
+<span id="L25" class="LineNr">  25 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> quit?  <span class="Comment"># only in tests</span>
+<span id="L26" class="LineNr">  26 </span>  <span class="Conceal">¦</span> trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[next-event]</span>
+<span id="L27" class="LineNr">  27 </span>  <span class="Conceal">¦</span> <span class="Comment"># 'touch' event</span>
+<span id="L28" class="LineNr">  28 </span>  <span class="Conceal">¦</span> t:<a href='../084console.mu.html#L12'>touch-event</a>, is-touch?:bool <span class="Special">&lt;-</span> maybe-convert e, <span class="Constant">touch:variant</span>
+<span id="L29" class="LineNr">  29 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L30" class="LineNr">  30 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-touch?
+<span id="L31" class="LineNr">  31 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='002-typing.mu.html#L48'>move-cursor-in-editor</a> <a href='../081print.mu.html#L4'>screen</a>, editor, t
+<span id="L32" class="LineNr">  32 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-event</span>
+<span id="L33" class="LineNr">  33 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L34" class="LineNr">  34 </span>  <span class="Conceal">¦</span> <span class="Comment"># keyboard events</span>
+<span id="L35" class="LineNr">  35 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L36" class="LineNr">  36 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> is-touch?
+<span id="L37" class="LineNr">  37 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> go-render?:bool <span class="Special">&lt;-</span> <a href='002-typing.mu.html#L164'>handle-keyboard-event</a> <a href='../081print.mu.html#L4'>screen</a>, editor, e
+<span id="L38" class="LineNr">  38 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L39" class="LineNr">  39 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> go-render?
+<span id="L40" class="LineNr">  40 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, editor
+<span id="L41" class="LineNr">  41 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L42" class="LineNr">  42 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L43" class="LineNr">  43 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L44" class="LineNr">  44 </span>  <span class="Delimiter">}</span>
 <span id="L45" class="LineNr">  45 </span>]
 <span id="L46" class="LineNr">  46 </span>
@@ -150,73 +151,73 @@ if ('onhashchange' in window) {
 <span id="L89" class="LineNr">  89 </span>  cursor-column:num <span class="Special">&lt;-</span> copy target-column
 <span id="L90" class="LineNr">  90 </span>  before-cursor:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
 <span id="L91" class="LineNr">  91 </span>  <span class="Delimiter">{</span>
-<span id="L92" class="LineNr">  92 </span><span class="Constant">    +next-character</span>
-<span id="L93" class="LineNr">  93 </span>    <span class="muControl">break-unless</span> curr
-<span id="L94" class="LineNr">  94 </span>    off-screen?:bool <span class="Special">&lt;-</span> greater-or-equal row, <a href='../081print.mu.html#L594'>screen-height</a>
-<span id="L95" class="LineNr">  95 </span>    <span class="muControl">break-if</span> off-screen?
-<span id="L96" class="LineNr">  96 </span>    <span class="Comment"># update editor.before-cursor</span>
-<span id="L97" class="LineNr">  97 </span>    <span class="Comment"># Doing so at the start of each iteration ensures it stays one step behind</span>
-<span id="L98" class="LineNr">  98 </span>    <span class="Comment"># the current character.</span>
-<span id="L99" class="LineNr">  99 </span>    <span class="Delimiter">{</span>
-<span id="L100" class="LineNr"> 100 </span>      at-cursor-row?:bool <span class="Special">&lt;-</span> equal row, cursor-row
-<span id="L101" class="LineNr"> 101 </span>      <span class="muControl">break-unless</span> at-cursor-row?
-<span id="L102" class="LineNr"> 102 </span>      at-cursor?:bool <span class="Special">&lt;-</span> equal column, cursor-column
-<span id="L103" class="LineNr"> 103 </span>      <span class="muControl">break-unless</span> at-cursor?
-<span id="L104" class="LineNr"> 104 </span>      before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
-<span id="L105" class="LineNr"> 105 </span>      *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
-<span id="L106" class="LineNr"> 106 </span>    <span class="Delimiter">}</span>
-<span id="L107" class="LineNr"> 107 </span>    c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
-<span id="L108" class="LineNr"> 108 </span>    <span class="Delimiter">{</span>
-<span id="L109" class="LineNr"> 109 </span>      <span class="Comment"># newline? move to left rather than 0</span>
-<span id="L110" class="LineNr"> 110 </span>      newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
-<span id="L111" class="LineNr"> 111 </span>      <span class="muControl">break-unless</span> newline?
-<span id="L112" class="LineNr"> 112 </span>      <span class="Comment"># adjust cursor if necessary</span>
-<span id="L113" class="LineNr"> 113 </span>      <span class="Delimiter">{</span>
-<span id="L114" class="LineNr"> 114 </span>        at-cursor-row?:bool <span class="Special">&lt;-</span> equal row, cursor-row
-<span id="L115" class="LineNr"> 115 </span>        <span class="muControl">break-unless</span> at-cursor-row?
-<span id="L116" class="LineNr"> 116 </span>        left-of-cursor?:bool <span class="Special">&lt;-</span> lesser-than column, cursor-column
-<span id="L117" class="LineNr"> 117 </span>        <span class="muControl">break-unless</span> left-of-cursor?
-<span id="L118" class="LineNr"> 118 </span>        cursor-column <span class="Special">&lt;-</span> copy column
-<span id="L119" class="LineNr"> 119 </span>        *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
-<span id="L120" class="LineNr"> 120 </span>        before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
-<span id="L121" class="LineNr"> 121 </span>        *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
-<span id="L122" class="LineNr"> 122 </span>      <span class="Delimiter">}</span>
-<span id="L123" class="LineNr"> 123 </span>      <span class="Comment"># skip to next line</span>
-<span id="L124" class="LineNr"> 124 </span>      row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
-<span id="L125" class="LineNr"> 125 </span>      column <span class="Special">&lt;-</span> copy left
-<span id="L126" class="LineNr"> 126 </span>      curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
-<span id="L127" class="LineNr"> 127 </span>      <a href='../065duplex_list.mu.html#L36'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> <a href='../065duplex_list.mu.html#L36'>prev</a>
-<span id="L128" class="LineNr"> 128 </span>      <span class="muControl">loop</span> <span class="Constant">+next-character</span>
-<span id="L129" class="LineNr"> 129 </span>    <span class="Delimiter">}</span>
-<span id="L130" class="LineNr"> 130 </span>    <span class="Delimiter">{</span>
-<span id="L131" class="LineNr"> 131 </span>      <span class="Comment"># at right? wrap. even if there's only one more letter left; we need</span>
-<span id="L132" class="LineNr"> 132 </span>      <span class="Comment"># room for clicking on the cursor after it.</span>
-<span id="L133" class="LineNr"> 133 </span>      at-right?:bool <span class="Special">&lt;-</span> equal column, right
-<span id="L134" class="LineNr"> 134 </span>      <span class="muControl">break-unless</span> at-right?
-<span id="L135" class="LineNr"> 135 </span>      column <span class="Special">&lt;-</span> copy left
-<span id="L136" class="LineNr"> 136 </span>      row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
-<span id="L137" class="LineNr"> 137 </span>      <span class="Comment"># don't increment curr/prev</span>
-<span id="L138" class="LineNr"> 138 </span>      <span class="muControl">loop</span> <span class="Constant">+next-character</span>
-<span id="L139" class="LineNr"> 139 </span>    <span class="Delimiter">}</span>
-<span id="L140" class="LineNr"> 140 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
-<span id="L141" class="LineNr"> 141 </span>    <a href='../065duplex_list.mu.html#L36'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> <a href='../065duplex_list.mu.html#L36'>prev</a>
-<span id="L142" class="LineNr"> 142 </span>    column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
-<span id="L143" class="LineNr"> 143 </span>    <span class="muControl">loop</span>
+<span id="L92" class="LineNr">  92 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> +next-character</span>
+<span id="L93" class="LineNr">  93 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> curr
+<span id="L94" class="LineNr">  94 </span>  <span class="Conceal">¦</span> off-screen?:bool <span class="Special">&lt;-</span> greater-or-equal row, <a href='../081print.mu.html#L594'>screen-height</a>
+<span id="L95" class="LineNr">  95 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> off-screen?
+<span id="L96" class="LineNr">  96 </span>  <span class="Conceal">¦</span> <span class="Comment"># update editor.before-cursor</span>
+<span id="L97" class="LineNr">  97 </span>  <span class="Conceal">¦</span> <span class="Comment"># Doing so at the start of each iteration ensures it stays one step behind</span>
+<span id="L98" class="LineNr">  98 </span>  <span class="Conceal">¦</span> <span class="Comment"># the current character.</span>
+<span id="L99" class="LineNr">  99 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L100" class="LineNr"> 100 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-cursor-row?:bool <span class="Special">&lt;-</span> equal row, cursor-row
+<span id="L101" class="LineNr"> 101 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-cursor-row?
+<span id="L102" class="LineNr"> 102 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-cursor?:bool <span class="Special">&lt;-</span> equal column, cursor-column
+<span id="L103" class="LineNr"> 103 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-cursor?
+<span id="L104" class="LineNr"> 104 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L105" class="LineNr"> 105 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
+<span id="L106" class="LineNr"> 106 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L107" class="LineNr"> 107 </span>  <span class="Conceal">¦</span> c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
+<span id="L108" class="LineNr"> 108 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L109" class="LineNr"> 109 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># newline? move to left rather than 0</span>
+<span id="L110" class="LineNr"> 110 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
+<span id="L111" class="LineNr"> 111 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> newline?
+<span id="L112" class="LineNr"> 112 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># adjust cursor if necessary</span>
+<span id="L113" class="LineNr"> 113 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L114" class="LineNr"> 114 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-cursor-row?:bool <span class="Special">&lt;-</span> equal row, cursor-row
+<span id="L115" class="LineNr"> 115 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-cursor-row?
+<span id="L116" class="LineNr"> 116 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> left-of-cursor?:bool <span class="Special">&lt;-</span> lesser-than column, cursor-column
+<span id="L117" class="LineNr"> 117 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> left-of-cursor?
+<span id="L118" class="LineNr"> 118 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> copy column
+<span id="L119" class="LineNr"> 119 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
+<span id="L120" class="LineNr"> 120 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L121" class="LineNr"> 121 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
+<span id="L122" class="LineNr"> 122 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L123" class="LineNr"> 123 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># skip to next line</span>
+<span id="L124" class="LineNr"> 124 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
+<span id="L125" class="LineNr"> 125 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> copy left
+<span id="L126" class="LineNr"> 126 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L127" class="LineNr"> 127 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L128" class="LineNr"> 128 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-character</span>
+<span id="L129" class="LineNr"> 129 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L130" class="LineNr"> 130 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L131" class="LineNr"> 131 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># at right? wrap. even if there's only one more letter left; we need</span>
+<span id="L132" class="LineNr"> 132 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># room for clicking on the cursor after it.</span>
+<span id="L133" class="LineNr"> 133 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-right?:bool <span class="Special">&lt;-</span> equal column, right
+<span id="L134" class="LineNr"> 134 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-right?
+<span id="L135" class="LineNr"> 135 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> copy left
+<span id="L136" class="LineNr"> 136 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
+<span id="L137" class="LineNr"> 137 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># don't increment curr/prev</span>
+<span id="L138" class="LineNr"> 138 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-character</span>
+<span id="L139" class="LineNr"> 139 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L140" class="LineNr"> 140 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L141" class="LineNr"> 141 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L142" class="LineNr"> 142 </span>  <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
+<span id="L143" class="LineNr"> 143 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L144" class="LineNr"> 144 </span>  <span class="Delimiter">}</span>
 <span id="L145" class="LineNr"> 145 </span>  <span class="Comment"># is cursor to the right of the last line? move to end</span>
 <span id="L146" class="LineNr"> 146 </span>  <span class="Delimiter">{</span>
-<span id="L147" class="LineNr"> 147 </span>    at-cursor-row?:bool <span class="Special">&lt;-</span> equal row, cursor-row
-<span id="L148" class="LineNr"> 148 </span>    cursor-outside-line?:bool <span class="Special">&lt;-</span> lesser-or-equal column, cursor-column
-<span id="L149" class="LineNr"> 149 </span>    before-cursor-on-same-line?:bool <span class="Special">&lt;-</span> and at-cursor-row?, cursor-outside-line?
-<span id="L150" class="LineNr"> 150 </span>    above-cursor-row?:bool <span class="Special">&lt;-</span> lesser-than row, cursor-row
-<span id="L151" class="LineNr"> 151 </span>    before-cursor?:bool <span class="Special">&lt;-</span> or before-cursor-on-same-line?, above-cursor-row?
-<span id="L152" class="LineNr"> 152 </span>    <span class="muControl">break-unless</span> before-cursor?
-<span id="L153" class="LineNr"> 153 </span>    cursor-row <span class="Special">&lt;-</span> copy row
-<span id="L154" class="LineNr"> 154 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
-<span id="L155" class="LineNr"> 155 </span>    cursor-column <span class="Special">&lt;-</span> copy column
-<span id="L156" class="LineNr"> 156 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
-<span id="L157" class="LineNr"> 157 </span>    before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
-<span id="L158" class="LineNr"> 158 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
+<span id="L147" class="LineNr"> 147 </span>  <span class="Conceal">¦</span> at-cursor-row?:bool <span class="Special">&lt;-</span> equal row, cursor-row
+<span id="L148" class="LineNr"> 148 </span>  <span class="Conceal">¦</span> cursor-outside-line?:bool <span class="Special">&lt;-</span> lesser-or-equal column, cursor-column
+<span id="L149" class="LineNr"> 149 </span>  <span class="Conceal">¦</span> before-cursor-on-same-line?:bool <span class="Special">&lt;-</span> and at-cursor-row?, cursor-outside-line?
+<span id="L150" class="LineNr"> 150 </span>  <span class="Conceal">¦</span> above-cursor-row?:bool <span class="Special">&lt;-</span> lesser-than row, cursor-row
+<span id="L151" class="LineNr"> 151 </span>  <span class="Conceal">¦</span> before-cursor?:bool <span class="Special">&lt;-</span> or before-cursor-on-same-line?, above-cursor-row?
+<span id="L152" class="LineNr"> 152 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> before-cursor?
+<span id="L153" class="LineNr"> 153 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> copy row
+<span id="L154" class="LineNr"> 154 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
+<span id="L155" class="LineNr"> 155 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> copy column
+<span id="L156" class="LineNr"> 156 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
+<span id="L157" class="LineNr"> 157 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L158" class="LineNr"> 158 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
 <span id="L159" class="LineNr"> 159 </span>  <span class="Delimiter">}</span>
 <span id="L160" class="LineNr"> 160 </span>]
 <span id="L161" class="LineNr"> 161 </span>
@@ -237,19 +238,19 @@ if ('onhashchange' in window) {
 <span id="L176" class="LineNr"> 176 </span>  save-column:num <span class="Special">&lt;-</span> copy cursor-column
 <span id="L177" class="LineNr"> 177 </span>  <span class="Comment"># character</span>
 <span id="L178" class="LineNr"> 178 </span>  <span class="Delimiter">{</span>
-<span id="L179" class="LineNr"> 179 </span>    c:char, is-unicode?:bool <span class="Special">&lt;-</span> maybe-convert e, <span class="Constant">text:variant</span>
-<span id="L180" class="LineNr"> 180 </span>    <span class="muControl">break-unless</span> is-unicode?
-<span id="L181" class="LineNr"> 181 </span>    trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[handle-keyboard-event: special character]</span>
-<span id="L182" class="LineNr"> 182 </span>    <span class="Comment"># exceptions for special characters go here</span>
-<span id="L183" class="LineNr"> 183 </span><span class="Constant">    <a href='002-typing.mu.html#L183'>&lt;handle-special-character&gt;</a></span>
-<span id="L184" class="LineNr"> 184 </span>    <span class="Comment"># ignore any other special characters</span>
-<span id="L185" class="LineNr"> 185 </span>    regular-character?:bool <span class="Special">&lt;-</span> greater-or-equal c, <span class="Constant">32/space</span>
-<span id="L186" class="LineNr"> 186 </span>    <span class="muControl">return-unless</span> regular-character?, <span class="Constant">0/don't-render</span>
-<span id="L187" class="LineNr"> 187 </span>    <span class="Comment"># otherwise type it in</span>
-<span id="L188" class="LineNr"> 188 </span><span class="Constant">    &lt;insert-character-begin&gt;</span>
-<span id="L189" class="LineNr"> 189 </span>    go-render? <span class="Special">&lt;-</span> <a href='002-typing.mu.html#L201'>insert-at-cursor</a> editor, c, <a href='../081print.mu.html#L4'>screen</a>
-<span id="L190" class="LineNr"> 190 </span><span class="Constant">    &lt;insert-character-end&gt;</span>
-<span id="L191" class="LineNr"> 191 </span>    <span class="muControl">return</span>
+<span id="L179" class="LineNr"> 179 </span>  <span class="Conceal">¦</span> c:char, is-unicode?:bool <span class="Special">&lt;-</span> maybe-convert e, <span class="Constant">text:variant</span>
+<span id="L180" class="LineNr"> 180 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-unicode?
+<span id="L181" class="LineNr"> 181 </span>  <span class="Conceal">¦</span> trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[handle-keyboard-event: special character]</span>
+<span id="L182" class="LineNr"> 182 </span>  <span class="Conceal">¦</span> <span class="Comment"># exceptions for special characters go here</span>
+<span id="L183" class="LineNr"> 183 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> <a href='002-typing.mu.html#L183'>&lt;handle-special-character&gt;</a></span>
+<span id="L184" class="LineNr"> 184 </span>  <span class="Conceal">¦</span> <span class="Comment"># ignore any other special characters</span>
+<span id="L185" class="LineNr"> 185 </span>  <span class="Conceal">¦</span> regular-character?:bool <span class="Special">&lt;-</span> greater-or-equal c, <span class="Constant">32/space</span>
+<span id="L186" class="LineNr"> 186 </span>  <span class="Conceal">¦</span> <span class="muControl">return-unless</span> regular-character?, <span class="Constant">0/don't-render</span>
+<span id="L187" class="LineNr"> 187 </span>  <span class="Conceal">¦</span> <span class="Comment"># otherwise type it in</span>
+<span id="L188" class="LineNr"> 188 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;insert-character-begin&gt;</span>
+<span id="L189" class="LineNr"> 189 </span>  <span class="Conceal">¦</span> go-render? <span class="Special">&lt;-</span> <a href='002-typing.mu.html#L201'>insert-at-cursor</a> editor, c, <a href='../081print.mu.html#L4'>screen</a>
+<span id="L190" class="LineNr"> 190 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;insert-character-end&gt;</span>
+<span id="L191" class="LineNr"> 191 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
 <span id="L192" class="LineNr"> 192 </span>  <span class="Delimiter">}</span>
 <span id="L193" class="LineNr"> 193 </span>  <span class="Comment"># special key to modify the text or move the cursor</span>
 <span id="L194" class="LineNr"> 194 </span>  k:num, is-keycode?:bool <span class="Special">&lt;-</span> maybe-convert e:<a href='../084console.mu.html#L4'>event</a>, <span class="Constant">keycode:variant</span>
@@ -281,41 +282,41 @@ if ('onhashchange' in window) {
 <span id="L220" class="LineNr"> 220 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
 <span id="L221" class="LineNr"> 221 </span>  <a href='../065duplex_list.mu.html#L29'>next</a>:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
 <span id="L222" class="LineNr"> 222 </span>  <span class="Delimiter">{</span>
-<span id="L223" class="LineNr"> 223 </span>    <span class="Comment"># at end of all text? no need to scroll? just print the character and leave</span>
-<span id="L224" class="LineNr"> 224 </span>    at-end?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L29'>next</a>, <span class="Constant">0/null</span>
-<span id="L225" class="LineNr"> 225 </span>    <span class="muControl">break-unless</span> at-end?
-<span id="L226" class="LineNr"> 226 </span>    bottom:num <span class="Special">&lt;-</span> subtract <a href='../081print.mu.html#L594'>screen-height</a>,<span class="Constant"> 1</span>
-<span id="L227" class="LineNr"> 227 </span>    at-bottom?:bool <span class="Special">&lt;-</span> equal save-row, bottom
-<span id="L228" class="LineNr"> 228 </span>    at-right?:bool <span class="Special">&lt;-</span> equal save-column, right
-<span id="L229" class="LineNr"> 229 </span>    overflow?:bool <span class="Special">&lt;-</span> and at-bottom?, at-right?
-<span id="L230" class="LineNr"> 230 </span>    <span class="muControl">break-if</span> overflow?
-<span id="L231" class="LineNr"> 231 </span>    <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, save-row, save-column
-<span id="L232" class="LineNr"> 232 </span>    print <a href='../081print.mu.html#L4'>screen</a>, c
-<span id="L233" class="LineNr"> 233 </span>    <span class="muControl">return</span> <span class="Constant">0/don't-render</span>
+<span id="L223" class="LineNr"> 223 </span>  <span class="Conceal">¦</span> <span class="Comment"># at end of all text? no need to scroll? just print the character and leave</span>
+<span id="L224" class="LineNr"> 224 </span>  <span class="Conceal">¦</span> at-end?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L29'>next</a>, <span class="Constant">0/null</span>
+<span id="L225" class="LineNr"> 225 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-end?
+<span id="L226" class="LineNr"> 226 </span>  <span class="Conceal">¦</span> bottom:num <span class="Special">&lt;-</span> subtract <a href='../081print.mu.html#L594'>screen-height</a>,<span class="Constant"> 1</span>
+<span id="L227" class="LineNr"> 227 </span>  <span class="Conceal">¦</span> at-bottom?:bool <span class="Special">&lt;-</span> equal save-row, bottom
+<span id="L228" class="LineNr"> 228 </span>  <span class="Conceal">¦</span> at-right?:bool <span class="Special">&lt;-</span> equal save-column, right
+<span id="L229" class="LineNr"> 229 </span>  <span class="Conceal">¦</span> overflow?:bool <span class="Special">&lt;-</span> and at-bottom?, at-right?
+<span id="L230" class="LineNr"> 230 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> overflow?
+<span id="L231" class="LineNr"> 231 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, save-row, save-column
+<span id="L232" class="LineNr"> 232 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, c
+<span id="L233" class="LineNr"> 233 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">0/don't-render</span>
 <span id="L234" class="LineNr"> 234 </span>  <span class="Delimiter">}</span>
 <span id="L235" class="LineNr"> 235 </span>  <span class="Delimiter">{</span>
-<span id="L236" class="LineNr"> 236 </span>    <span class="Comment"># not at right margin? print the character and rest of line</span>
-<span id="L237" class="LineNr"> 237 </span>    <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L29'>next</a>
-<span id="L238" class="LineNr"> 238 </span>    at-right?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-column, <a href='../081print.mu.html#L581'>screen-width</a>
-<span id="L239" class="LineNr"> 239 </span>    <span class="muControl">break-if</span> at-right?
-<span id="L240" class="LineNr"> 240 </span>    curr:&amp;:duplex-list:char <span class="Special">&lt;-</span> copy before-cursor
-<span id="L241" class="LineNr"> 241 </span>    <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, save-row, save-column
-<span id="L242" class="LineNr"> 242 </span>    curr-column:num <span class="Special">&lt;-</span> copy save-column
-<span id="L243" class="LineNr"> 243 </span>    <span class="Delimiter">{</span>
-<span id="L244" class="LineNr"> 244 </span>      <span class="Comment"># hit right margin? give up and let caller render</span>
-<span id="L245" class="LineNr"> 245 </span>      at-right?:bool <span class="Special">&lt;-</span> greater-than curr-column, right
-<span id="L246" class="LineNr"> 246 </span>      <span class="muControl">return-if</span> at-right?, <span class="Constant">1/go-render</span>
-<span id="L247" class="LineNr"> 247 </span>      <span class="muControl">break-unless</span> curr
-<span id="L248" class="LineNr"> 248 </span>      <span class="Comment"># newline? done.</span>
-<span id="L249" class="LineNr"> 249 </span>      currc:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
-<span id="L250" class="LineNr"> 250 </span>      at-newline?:bool <span class="Special">&lt;-</span> equal currc, <span class="Constant">10/newline</span>
-<span id="L251" class="LineNr"> 251 </span>      <span class="muControl">break-if</span> at-newline?
-<span id="L252" class="LineNr"> 252 </span>      print <a href='../081print.mu.html#L4'>screen</a>, currc
-<span id="L253" class="LineNr"> 253 </span>      curr-column <span class="Special">&lt;-</span> add curr-column,<span class="Constant"> 1</span>
-<span id="L254" class="LineNr"> 254 </span>      curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
-<span id="L255" class="LineNr"> 255 </span>      <span class="muControl">loop</span>
-<span id="L256" class="LineNr"> 256 </span>    <span class="Delimiter">}</span>
-<span id="L257" class="LineNr"> 257 </span>    <span class="muControl">return</span> <span class="Constant">0/don't-render</span>
+<span id="L236" class="LineNr"> 236 </span>  <span class="Conceal">¦</span> <span class="Comment"># not at right margin? print the character and rest of line</span>
+<span id="L237" class="LineNr"> 237 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L29'>next</a>
+<span id="L238" class="LineNr"> 238 </span>  <span class="Conceal">¦</span> at-right?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-column, <a href='../081print.mu.html#L581'>screen-width</a>
+<span id="L239" class="LineNr"> 239 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-right?
+<span id="L240" class="LineNr"> 240 </span>  <span class="Conceal">¦</span> curr:&amp;:duplex-list:char <span class="Special">&lt;-</span> copy before-cursor
+<span id="L241" class="LineNr"> 241 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, save-row, save-column
+<span id="L242" class="LineNr"> 242 </span>  <span class="Conceal">¦</span> curr-column:num <span class="Special">&lt;-</span> copy save-column
+<span id="L243" class="LineNr"> 243 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L244" class="LineNr"> 244 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># hit right margin? give up and let caller render</span>
+<span id="L245" class="LineNr"> 245 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-right?:bool <span class="Special">&lt;-</span> greater-than curr-column, right
+<span id="L246" class="LineNr"> 246 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">return-if</span> at-right?, <span class="Constant">1/go-render</span>
+<span id="L247" class="LineNr"> 247 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> curr
+<span id="L248" class="LineNr"> 248 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># newline? done.</span>
+<span id="L249" class="LineNr"> 249 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> currc:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
+<span id="L250" class="LineNr"> 250 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-newline?:bool <span class="Special">&lt;-</span> equal currc, <span class="Constant">10/newline</span>
+<span id="L251" class="LineNr"> 251 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-newline?
+<span id="L252" class="LineNr"> 252 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, currc
+<span id="L253" class="LineNr"> 253 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr-column <span class="Special">&lt;-</span> add curr-column,<span class="Constant"> 1</span>
+<span id="L254" class="LineNr"> 254 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L255" class="LineNr"> 255 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span>
+<span id="L256" class="LineNr"> 256 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L257" class="LineNr"> 257 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">0/don't-render</span>
 <span id="L258" class="LineNr"> 258 </span>  <span class="Delimiter">}</span>
 <span id="L259" class="LineNr"> 259 </span>  <span class="muControl">return</span> <span class="Constant">1/go-render</span>
 <span id="L260" class="LineNr"> 260 </span>]
@@ -341,13 +342,13 @@ if ('onhashchange' in window) {
 <span id="L280" class="LineNr"> 280 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L281" class="LineNr"> 281 </span>  assume-console <span class="Constant">[]</span>
 <span id="L282" class="LineNr"> 282 </span>  run [
-<span id="L283" class="LineNr"> 283 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L283" class="LineNr"> 283 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L284" class="LineNr"> 284 </span>  ]
 <span id="L285" class="LineNr"> 285 </span>  screen-should-contain [
-<span id="L286" class="LineNr"> 286 </span>   <span class="Constant"> .          .</span>
-<span id="L287" class="LineNr"> 287 </span>   <span class="Constant"> .abc       .</span>
-<span id="L288" class="LineNr"> 288 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L289" class="LineNr"> 289 </span>   <span class="Constant"> .          .</span>
+<span id="L286" class="LineNr"> 286 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L287" class="LineNr"> 287 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L288" class="LineNr"> 288 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L289" class="LineNr"> 289 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L290" class="LineNr"> 290 </span>  ]
 <span id="L291" class="LineNr"> 291 </span>]
 <span id="L292" class="LineNr"> 292 </span>
@@ -358,22 +359,22 @@ if ('onhashchange' in window) {
 <span id="L297" class="LineNr"> 297 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L298" class="LineNr"> 298 </span>  $clear-trace
 <span id="L299" class="LineNr"> 299 </span>  assume-console [
-<span id="L300" class="LineNr"> 300 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>  <span class="Comment"># on the 'b'</span>
+<span id="L300" class="LineNr"> 300 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>  <span class="Comment"># on the 'b'</span>
 <span id="L301" class="LineNr"> 301 </span>  ]
 <span id="L302" class="LineNr"> 302 </span>  run [
-<span id="L303" class="LineNr"> 303 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L304" class="LineNr"> 304 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L305" class="LineNr"> 305 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L303" class="LineNr"> 303 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L304" class="LineNr"> 304 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L305" class="LineNr"> 305 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L306" class="LineNr"> 306 </span>  ]
 <span id="L307" class="LineNr"> 307 </span>  screen-should-contain [
-<span id="L308" class="LineNr"> 308 </span>   <span class="Constant"> .          .</span>
-<span id="L309" class="LineNr"> 309 </span>   <span class="Constant"> .abc       .</span>
-<span id="L310" class="LineNr"> 310 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L311" class="LineNr"> 311 </span>   <span class="Constant"> .          .</span>
+<span id="L308" class="LineNr"> 308 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L309" class="LineNr"> 309 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L310" class="LineNr"> 310 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L311" class="LineNr"> 311 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L312" class="LineNr"> 312 </span>  ]
 <span id="L313" class="LineNr"> 313 </span>  memory-should-contain [
-<span id="L314" class="LineNr"> 314 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># cursor is at row 0..</span>
-<span id="L315" class="LineNr"> 315 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># ..and column 1</span>
+<span id="L314" class="LineNr"> 314 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># cursor is at row 0..</span>
+<span id="L315" class="LineNr"> 315 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># ..and column 1</span>
 <span id="L316" class="LineNr"> 316 </span>  ]
 <span id="L317" class="LineNr"> 317 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L318" class="LineNr"> 318 </span>]
@@ -384,16 +385,16 @@ if ('onhashchange' in window) {
 <span id="L323" class="LineNr"> 323 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> <span class="Constant">[abc]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L324" class="LineNr"> 324 </span>  $clear-trace
 <span id="L325" class="LineNr"> 325 </span>  assume-console [
-<span id="L326" class="LineNr"> 326 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 7</span>  <span class="Comment"># last line, to the right of text</span>
+<span id="L326" class="LineNr"> 326 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 7</span>  <span class="Comment"># last line, to the right of text</span>
 <span id="L327" class="LineNr"> 327 </span>  ]
 <span id="L328" class="LineNr"> 328 </span>  run [
-<span id="L329" class="LineNr"> 329 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L330" class="LineNr"> 330 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L331" class="LineNr"> 331 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L329" class="LineNr"> 329 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L330" class="LineNr"> 330 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L331" class="LineNr"> 331 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L332" class="LineNr"> 332 </span>  ]
 <span id="L333" class="LineNr"> 333 </span>  memory-should-contain [
-<span id="L334" class="LineNr"> 334 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># cursor row</span>
-<span id="L335" class="LineNr"> 335 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>  <span class="Comment"># cursor column</span>
+<span id="L334" class="LineNr"> 334 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># cursor row</span>
+<span id="L335" class="LineNr"> 335 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>  <span class="Comment"># cursor column</span>
 <span id="L336" class="LineNr"> 336 </span>  ]
 <span id="L337" class="LineNr"> 337 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L338" class="LineNr"> 338 </span>]
@@ -406,16 +407,16 @@ if ('onhashchange' in window) {
 <span id="L345" class="LineNr"> 345 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L346" class="LineNr"> 346 </span>  $clear-trace
 <span id="L347" class="LineNr"> 347 </span>  assume-console [
-<span id="L348" class="LineNr"> 348 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 7</span>  <span class="Comment"># interior line, to the right of text</span>
+<span id="L348" class="LineNr"> 348 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 7</span>  <span class="Comment"># interior line, to the right of text</span>
 <span id="L349" class="LineNr"> 349 </span>  ]
 <span id="L350" class="LineNr"> 350 </span>  run [
-<span id="L351" class="LineNr"> 351 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L352" class="LineNr"> 352 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L353" class="LineNr"> 353 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L351" class="LineNr"> 351 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L352" class="LineNr"> 352 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L353" class="LineNr"> 353 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L354" class="LineNr"> 354 </span>  ]
 <span id="L355" class="LineNr"> 355 </span>  memory-should-contain [
-<span id="L356" class="LineNr"> 356 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># cursor row</span>
-<span id="L357" class="LineNr"> 357 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>  <span class="Comment"># cursor column</span>
+<span id="L356" class="LineNr"> 356 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># cursor row</span>
+<span id="L357" class="LineNr"> 357 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>  <span class="Comment"># cursor column</span>
 <span id="L358" class="LineNr"> 358 </span>  ]
 <span id="L359" class="LineNr"> 359 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L360" class="LineNr"> 360 </span>]
@@ -428,16 +429,16 @@ if ('onhashchange' in window) {
 <span id="L367" class="LineNr"> 367 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L368" class="LineNr"> 368 </span>  $clear-trace
 <span id="L369" class="LineNr"> 369 </span>  assume-console [
-<span id="L370" class="LineNr"> 370 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 7</span>  <span class="Comment"># below text</span>
+<span id="L370" class="LineNr"> 370 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 7</span>  <span class="Comment"># below text</span>
 <span id="L371" class="LineNr"> 371 </span>  ]
 <span id="L372" class="LineNr"> 372 </span>  run [
-<span id="L373" class="LineNr"> 373 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L374" class="LineNr"> 374 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L375" class="LineNr"> 375 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L373" class="LineNr"> 373 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L374" class="LineNr"> 374 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L375" class="LineNr"> 375 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L376" class="LineNr"> 376 </span>  ]
 <span id="L377" class="LineNr"> 377 </span>  memory-should-contain [
-<span id="L378" class="LineNr"> 378 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>  <span class="Comment"># cursor row</span>
-<span id="L379" class="LineNr"> 379 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>  <span class="Comment"># cursor column</span>
+<span id="L378" class="LineNr"> 378 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>  <span class="Comment"># cursor row</span>
+<span id="L379" class="LineNr"> 379 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>  <span class="Comment"># cursor column</span>
 <span id="L380" class="LineNr"> 380 </span>  ]
 <span id="L381" class="LineNr"> 381 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L382" class="LineNr"> 382 </span>]
@@ -450,23 +451,23 @@ if ('onhashchange' in window) {
 <span id="L389" class="LineNr"> 389 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L390" class="LineNr"> 390 </span>  $clear-trace
 <span id="L391" class="LineNr"> 391 </span>  assume-console [
-<span id="L392" class="LineNr"> 392 </span>    <span class="Comment"># click on right half of screen</span>
-<span id="L393" class="LineNr"> 393 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 8</span>
+<span id="L392" class="LineNr"> 392 </span>  <span class="Conceal">¦</span> <span class="Comment"># click on right half of screen</span>
+<span id="L393" class="LineNr"> 393 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 8</span>
 <span id="L394" class="LineNr"> 394 </span>  ]
 <span id="L395" class="LineNr"> 395 </span>  run [
-<span id="L396" class="LineNr"> 396 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L397" class="LineNr"> 397 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L398" class="LineNr"> 398 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L396" class="LineNr"> 396 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L397" class="LineNr"> 397 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L398" class="LineNr"> 398 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L399" class="LineNr"> 399 </span>  ]
 <span id="L400" class="LineNr"> 400 </span>  screen-should-contain [
-<span id="L401" class="LineNr"> 401 </span>   <span class="Constant"> .          .</span>
-<span id="L402" class="LineNr"> 402 </span>   <span class="Constant"> .abc       .</span>
-<span id="L403" class="LineNr"> 403 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
-<span id="L404" class="LineNr"> 404 </span>   <span class="Constant"> .          .</span>
+<span id="L401" class="LineNr"> 401 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L402" class="LineNr"> 402 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L403" class="LineNr"> 403 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌     .</span>
+<span id="L404" class="LineNr"> 404 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L405" class="LineNr"> 405 </span>  ]
 <span id="L406" class="LineNr"> 406 </span>  memory-should-contain [
-<span id="L407" class="LineNr"> 407 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># no change to cursor row</span>
-<span id="L408" class="LineNr"> 408 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># ..or column</span>
+<span id="L407" class="LineNr"> 407 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># no change to cursor row</span>
+<span id="L408" class="LineNr"> 408 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># ..or column</span>
 <span id="L409" class="LineNr"> 409 </span>  ]
 <span id="L410" class="LineNr"> 410 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L411" class="LineNr"> 411 </span>]
@@ -478,18 +479,18 @@ if ('onhashchange' in window) {
 <span id="L417" class="LineNr"> 417 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L418" class="LineNr"> 418 </span>  $clear-trace
 <span id="L419" class="LineNr"> 419 </span>  assume-console [
-<span id="L420" class="LineNr"> 420 </span>    <span class="Comment"># click on first, 'menu' row</span>
-<span id="L421" class="LineNr"> 421 </span>    left-click<span class="Constant"> 0</span>,<span class="Constant"> 3</span>
+<span id="L420" class="LineNr"> 420 </span>  <span class="Conceal">¦</span> <span class="Comment"># click on first, 'menu' row</span>
+<span id="L421" class="LineNr"> 421 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 0</span>,<span class="Constant"> 3</span>
 <span id="L422" class="LineNr"> 422 </span>  ]
 <span id="L423" class="LineNr"> 423 </span>  run [
-<span id="L424" class="LineNr"> 424 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L425" class="LineNr"> 425 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L426" class="LineNr"> 426 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L424" class="LineNr"> 424 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L425" class="LineNr"> 425 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L426" class="LineNr"> 426 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L427" class="LineNr"> 427 </span>  ]
 <span id="L428" class="LineNr"> 428 </span>  <span class="Comment"># no change to cursor</span>
 <span id="L429" class="LineNr"> 429 </span>  memory-should-contain [
-<span id="L430" class="LineNr"> 430 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L431" class="LineNr"> 431 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
+<span id="L430" class="LineNr"> 430 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L431" class="LineNr"> 431 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
 <span id="L432" class="LineNr"> 432 </span>  ]
 <span id="L433" class="LineNr"> 433 </span>]
 <span id="L434" class="LineNr"> 434 </span>
@@ -500,16 +501,16 @@ if ('onhashchange' in window) {
 <span id="L439" class="LineNr"> 439 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L440" class="LineNr"> 440 </span>  $clear-trace
 <span id="L441" class="LineNr"> 441 </span>  assume-console [
-<span id="L442" class="LineNr"> 442 </span>    type <span class="Constant">[abc]</span>
+<span id="L442" class="LineNr"> 442 </span>  <span class="Conceal">¦</span> type <span class="Constant">[abc]</span>
 <span id="L443" class="LineNr"> 443 </span>  ]
 <span id="L444" class="LineNr"> 444 </span>  run [
-<span id="L445" class="LineNr"> 445 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L445" class="LineNr"> 445 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L446" class="LineNr"> 446 </span>  ]
 <span id="L447" class="LineNr"> 447 </span>  screen-should-contain [
-<span id="L448" class="LineNr"> 448 </span>   <span class="Constant"> .          .</span>
-<span id="L449" class="LineNr"> 449 </span>   <span class="Constant"> .abc       .</span>
-<span id="L450" class="LineNr"> 450 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
-<span id="L451" class="LineNr"> 451 </span>   <span class="Constant"> .          .</span>
+<span id="L448" class="LineNr"> 448 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L449" class="LineNr"> 449 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L450" class="LineNr"> 450 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌     .</span>
+<span id="L451" class="LineNr"> 451 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L452" class="LineNr"> 452 </span>  ]
 <span id="L453" class="LineNr"> 453 </span>  check-trace-count-for-label<span class="Constant"> 3</span>, <span class="Constant">[print-character]</span>
 <span id="L454" class="LineNr"> 454 </span>]
@@ -522,18 +523,18 @@ if ('onhashchange' in window) {
 <span id="L461" class="LineNr"> 461 </span>  $clear-trace
 <span id="L462" class="LineNr"> 462 </span>  <span class="Comment"># type two letters at different places</span>
 <span id="L463" class="LineNr"> 463 </span>  assume-console [
-<span id="L464" class="LineNr"> 464 </span>    type <span class="Constant">[0]</span>
-<span id="L465" class="LineNr"> 465 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 2</span>
-<span id="L466" class="LineNr"> 466 </span>    type <span class="Constant">[d]</span>
+<span id="L464" class="LineNr"> 464 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
+<span id="L465" class="LineNr"> 465 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 2</span>
+<span id="L466" class="LineNr"> 466 </span>  <span class="Conceal">¦</span> type <span class="Constant">[d]</span>
 <span id="L467" class="LineNr"> 467 </span>  ]
 <span id="L468" class="LineNr"> 468 </span>  run [
-<span id="L469" class="LineNr"> 469 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L469" class="LineNr"> 469 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L470" class="LineNr"> 470 </span>  ]
 <span id="L471" class="LineNr"> 471 </span>  screen-should-contain [
-<span id="L472" class="LineNr"> 472 </span>   <span class="Constant"> .          .</span>
-<span id="L473" class="LineNr"> 473 </span>   <span class="Constant"> .0adbc     .</span>
-<span id="L474" class="LineNr"> 474 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L475" class="LineNr"> 475 </span>   <span class="Constant"> .          .</span>
+<span id="L472" class="LineNr"> 472 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L473" class="LineNr"> 473 </span>  <span class="Conceal">¦</span><span class="Constant"> .0adbc     .</span>
+<span id="L474" class="LineNr"> 474 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L475" class="LineNr"> 475 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L476" class="LineNr"> 476 </span>  ]
 <span id="L477" class="LineNr"> 477 </span>  check-trace-count-for-label<span class="Constant"> 7</span>, <span class="Constant">[print-character]</span>  <span class="Comment"># 4 for first letter, 3 for second</span>
 <span id="L478" class="LineNr"> 478 </span>]
@@ -545,17 +546,17 @@ if ('onhashchange' in window) {
 <span id="L484" class="LineNr"> 484 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L485" class="LineNr"> 485 </span>  $clear-trace
 <span id="L486" class="LineNr"> 486 </span>  assume-console [
-<span id="L487" class="LineNr"> 487 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 5</span>  <span class="Comment"># right of last line</span>
-<span id="L488" class="LineNr"> 488 </span>    type <span class="Constant">[d]</span>
+<span id="L487" class="LineNr"> 487 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 5</span>  <span class="Comment"># right of last line</span>
+<span id="L488" class="LineNr"> 488 </span>  <span class="Conceal">¦</span> type <span class="Constant">[d]</span>
 <span id="L489" class="LineNr"> 489 </span>  ]
 <span id="L490" class="LineNr"> 490 </span>  run [
-<span id="L491" class="LineNr"> 491 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L491" class="LineNr"> 491 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L492" class="LineNr"> 492 </span>  ]
 <span id="L493" class="LineNr"> 493 </span>  screen-should-contain [
-<span id="L494" class="LineNr"> 494 </span>   <span class="Constant"> .          .</span>
-<span id="L495" class="LineNr"> 495 </span>   <span class="Constant"> .abcd      .</span>
-<span id="L496" class="LineNr"> 496 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L497" class="LineNr"> 497 </span>   <span class="Constant"> .          .</span>
+<span id="L494" class="LineNr"> 494 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L495" class="LineNr"> 495 </span>  <span class="Conceal">¦</span><span class="Constant"> .abcd      .</span>
+<span id="L496" class="LineNr"> 496 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L497" class="LineNr"> 497 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L498" class="LineNr"> 498 </span>  ]
 <span id="L499" class="LineNr"> 499 </span>  check-trace-count-for-label<span class="Constant"> 1</span>, <span class="Constant">[print-character]</span>
 <span id="L500" class="LineNr"> 500 </span>]
@@ -569,18 +570,18 @@ if ('onhashchange' in window) {
 <span id="L508" class="LineNr"> 508 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L509" class="LineNr"> 509 </span>  $clear-trace
 <span id="L510" class="LineNr"> 510 </span>  assume-console [
-<span id="L511" class="LineNr"> 511 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 5</span>  <span class="Comment"># right of non-last line</span>
-<span id="L512" class="LineNr"> 512 </span>    type <span class="Constant">[e]</span>
+<span id="L511" class="LineNr"> 511 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 5</span>  <span class="Comment"># right of non-last line</span>
+<span id="L512" class="LineNr"> 512 </span>  <span class="Conceal">¦</span> type <span class="Constant">[e]</span>
 <span id="L513" class="LineNr"> 513 </span>  ]
 <span id="L514" class="LineNr"> 514 </span>  run [
-<span id="L515" class="LineNr"> 515 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L515" class="LineNr"> 515 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L516" class="LineNr"> 516 </span>  ]
 <span id="L517" class="LineNr"> 517 </span>  screen-should-contain [
-<span id="L518" class="LineNr"> 518 </span>   <span class="Constant"> .          .</span>
-<span id="L519" class="LineNr"> 519 </span>   <span class="Constant"> .abce      .</span>
-<span id="L520" class="LineNr"> 520 </span>   <span class="Constant"> .d         .</span>
-<span id="L521" class="LineNr"> 521 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L522" class="LineNr"> 522 </span>   <span class="Constant"> .          .</span>
+<span id="L518" class="LineNr"> 518 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L519" class="LineNr"> 519 </span>  <span class="Conceal">¦</span><span class="Constant"> .abce      .</span>
+<span id="L520" class="LineNr"> 520 </span>  <span class="Conceal">¦</span><span class="Constant"> .d         .</span>
+<span id="L521" class="LineNr"> 521 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L522" class="LineNr"> 522 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L523" class="LineNr"> 523 </span>  ]
 <span id="L524" class="LineNr"> 524 </span>  check-trace-count-for-label<span class="Constant"> 1</span>, <span class="Constant">[print-character]</span>
 <span id="L525" class="LineNr"> 525 </span>]
@@ -592,17 +593,17 @@ if ('onhashchange' in window) {
 <span id="L531" class="LineNr"> 531 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L532" class="LineNr"> 532 </span>  $clear-trace
 <span id="L533" class="LineNr"> 533 </span>  assume-console [
-<span id="L534" class="LineNr"> 534 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 5</span>  <span class="Comment"># below all text</span>
-<span id="L535" class="LineNr"> 535 </span>    type <span class="Constant">[d]</span>
+<span id="L534" class="LineNr"> 534 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 5</span>  <span class="Comment"># below all text</span>
+<span id="L535" class="LineNr"> 535 </span>  <span class="Conceal">¦</span> type <span class="Constant">[d]</span>
 <span id="L536" class="LineNr"> 536 </span>  ]
 <span id="L537" class="LineNr"> 537 </span>  run [
-<span id="L538" class="LineNr"> 538 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L538" class="LineNr"> 538 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L539" class="LineNr"> 539 </span>  ]
 <span id="L540" class="LineNr"> 540 </span>  screen-should-contain [
-<span id="L541" class="LineNr"> 541 </span>   <span class="Constant"> .          .</span>
-<span id="L542" class="LineNr"> 542 </span>   <span class="Constant"> .abcd      .</span>
-<span id="L543" class="LineNr"> 543 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L544" class="LineNr"> 544 </span>   <span class="Constant"> .          .</span>
+<span id="L541" class="LineNr"> 541 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L542" class="LineNr"> 542 </span>  <span class="Conceal">¦</span><span class="Constant"> .abcd      .</span>
+<span id="L543" class="LineNr"> 543 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L544" class="LineNr"> 544 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L545" class="LineNr"> 545 </span>  ]
 <span id="L546" class="LineNr"> 546 </span>  check-trace-count-for-label<span class="Constant"> 1</span>, <span class="Constant">[print-character]</span>
 <span id="L547" class="LineNr"> 547 </span>]
@@ -616,18 +617,18 @@ if ('onhashchange' in window) {
 <span id="L555" class="LineNr"> 555 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L556" class="LineNr"> 556 </span>  $clear-trace
 <span id="L557" class="LineNr"> 557 </span>  assume-console [
-<span id="L558" class="LineNr"> 558 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 5</span>  <span class="Comment"># below all text</span>
-<span id="L559" class="LineNr"> 559 </span>    type <span class="Constant">[e]</span>
+<span id="L558" class="LineNr"> 558 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 5</span>  <span class="Comment"># below all text</span>
+<span id="L559" class="LineNr"> 559 </span>  <span class="Conceal">¦</span> type <span class="Constant">[e]</span>
 <span id="L560" class="LineNr"> 560 </span>  ]
 <span id="L561" class="LineNr"> 561 </span>  run [
-<span id="L562" class="LineNr"> 562 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L562" class="LineNr"> 562 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L563" class="LineNr"> 563 </span>  ]
 <span id="L564" class="LineNr"> 564 </span>  screen-should-contain [
-<span id="L565" class="LineNr"> 565 </span>   <span class="Constant"> .          .</span>
-<span id="L566" class="LineNr"> 566 </span>   <span class="Constant"> .abc       .</span>
-<span id="L567" class="LineNr"> 567 </span>   <span class="Constant"> .de        .</span>
-<span id="L568" class="LineNr"> 568 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L569" class="LineNr"> 569 </span>   <span class="Constant"> .          .</span>
+<span id="L565" class="LineNr"> 565 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L566" class="LineNr"> 566 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L567" class="LineNr"> 567 </span>  <span class="Conceal">¦</span><span class="Constant"> .de        .</span>
+<span id="L568" class="LineNr"> 568 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L569" class="LineNr"> 569 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L570" class="LineNr"> 570 </span>  ]
 <span id="L571" class="LineNr"> 571 </span>  check-trace-count-for-label<span class="Constant"> 1</span>, <span class="Constant">[print-character]</span>
 <span id="L572" class="LineNr"> 572 </span>]
@@ -641,18 +642,18 @@ if ('onhashchange' in window) {
 <span id="L580" class="LineNr"> 580 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L581" class="LineNr"> 581 </span>  $clear-trace
 <span id="L582" class="LineNr"> 582 </span>  assume-console [
-<span id="L583" class="LineNr"> 583 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 5</span>  <span class="Comment"># below all text</span>
-<span id="L584" class="LineNr"> 584 </span>    type <span class="Constant">[ef]</span>
+<span id="L583" class="LineNr"> 583 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 5</span>  <span class="Comment"># below all text</span>
+<span id="L584" class="LineNr"> 584 </span>  <span class="Conceal">¦</span> type <span class="Constant">[ef]</span>
 <span id="L585" class="LineNr"> 585 </span>  ]
 <span id="L586" class="LineNr"> 586 </span>  run [
-<span id="L587" class="LineNr"> 587 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L587" class="LineNr"> 587 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L588" class="LineNr"> 588 </span>  ]
 <span id="L589" class="LineNr"> 589 </span>  screen-should-contain [
-<span id="L590" class="LineNr"> 590 </span>   <span class="Constant"> .          .</span>
-<span id="L591" class="LineNr"> 591 </span>   <span class="Constant"> .abc       .</span>
-<span id="L592" class="LineNr"> 592 </span>   <span class="Constant"> .def       .</span>
-<span id="L593" class="LineNr"> 593 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L594" class="LineNr"> 594 </span>   <span class="Constant"> .          .</span>
+<span id="L590" class="LineNr"> 590 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L591" class="LineNr"> 591 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L592" class="LineNr"> 592 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
+<span id="L593" class="LineNr"> 593 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L594" class="LineNr"> 594 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L595" class="LineNr"> 595 </span>  ]
 <span id="L596" class="LineNr"> 596 </span>  check-trace-count-for-label<span class="Constant"> 2</span>, <span class="Constant">[print-character]</span>
 <span id="L597" class="LineNr"> 597 </span>]
@@ -663,16 +664,16 @@ if ('onhashchange' in window) {
 <span id="L602" class="LineNr"> 602 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> <span class="Constant">[ab]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
 <span id="L603" class="LineNr"> 603 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L604" class="LineNr"> 604 </span>  assume-console [
-<span id="L605" class="LineNr"> 605 </span>    type <span class="Constant">[01]</span>
+<span id="L605" class="LineNr"> 605 </span>  <span class="Conceal">¦</span> type <span class="Constant">[01]</span>
 <span id="L606" class="LineNr"> 606 </span>  ]
 <span id="L607" class="LineNr"> 607 </span>  run [
-<span id="L608" class="LineNr"> 608 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L608" class="LineNr"> 608 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L609" class="LineNr"> 609 </span>  ]
 <span id="L610" class="LineNr"> 610 </span>  screen-should-contain [
-<span id="L611" class="LineNr"> 611 </span>   <span class="Constant"> .          .</span>
-<span id="L612" class="LineNr"> 612 </span>   <span class="Constant"> .01ab      .</span>
-<span id="L613" class="LineNr"> 613 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
-<span id="L614" class="LineNr"> 614 </span>   <span class="Constant"> .          .</span>
+<span id="L611" class="LineNr"> 611 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L612" class="LineNr"> 612 </span>  <span class="Conceal">¦</span><span class="Constant"> .01ab      .</span>
+<span id="L613" class="LineNr"> 613 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌     .</span>
+<span id="L614" class="LineNr"> 614 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L615" class="LineNr"> 615 </span>  ]
 <span id="L616" class="LineNr"> 616 </span>]
 <span id="L617" class="LineNr"> 617 </span>
@@ -685,33 +686,33 @@ if ('onhashchange' in window) {
 <span id="L624" class="LineNr"> 624 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L625" class="LineNr"> 625 </span>  <span class="Comment"># type a letter</span>
 <span id="L626" class="LineNr"> 626 </span>  assume-console [
-<span id="L627" class="LineNr"> 627 </span>    type <span class="Constant">[e]</span>
+<span id="L627" class="LineNr"> 627 </span>  <span class="Conceal">¦</span> type <span class="Constant">[e]</span>
 <span id="L628" class="LineNr"> 628 </span>  ]
 <span id="L629" class="LineNr"> 629 </span>  run [
-<span id="L630" class="LineNr"> 630 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L630" class="LineNr"> 630 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L631" class="LineNr"> 631 </span>  ]
 <span id="L632" class="LineNr"> 632 </span>  <span class="Comment"># no wrap yet</span>
 <span id="L633" class="LineNr"> 633 </span>  screen-should-contain [
-<span id="L634" class="LineNr"> 634 </span>   <span class="Constant"> .     .</span>
-<span id="L635" class="LineNr"> 635 </span>   <span class="Constant"> .eabc .</span>
-<span id="L636" class="LineNr"> 636 </span><span class="Constant">    .╌╌╌╌╌.</span>
-<span id="L637" class="LineNr"> 637 </span>   <span class="Constant"> .     .</span>
-<span id="L638" class="LineNr"> 638 </span>   <span class="Constant"> .     .</span>
+<span id="L634" class="LineNr"> 634 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L635" class="LineNr"> 635 </span>  <span class="Conceal">¦</span><span class="Constant"> .eabc .</span>
+<span id="L636" class="LineNr"> 636 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌.</span>
+<span id="L637" class="LineNr"> 637 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L638" class="LineNr"> 638 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
 <span id="L639" class="LineNr"> 639 </span>  ]
 <span id="L640" class="LineNr"> 640 </span>  <span class="Comment"># type a second letter</span>
 <span id="L641" class="LineNr"> 641 </span>  assume-console [
-<span id="L642" class="LineNr"> 642 </span>    type <span class="Constant">[f]</span>
+<span id="L642" class="LineNr"> 642 </span>  <span class="Conceal">¦</span> type <span class="Constant">[f]</span>
 <span id="L643" class="LineNr"> 643 </span>  ]
 <span id="L644" class="LineNr"> 644 </span>  run [
-<span id="L645" class="LineNr"> 645 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L645" class="LineNr"> 645 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L646" class="LineNr"> 646 </span>  ]
 <span id="L647" class="LineNr"> 647 </span>  <span class="Comment"># now wrap</span>
 <span id="L648" class="LineNr"> 648 </span>  screen-should-contain [
-<span id="L649" class="LineNr"> 649 </span>   <span class="Constant"> .     .</span>
-<span id="L650" class="LineNr"> 650 </span><span class="Constant">    .efab↩.</span>
-<span id="L651" class="LineNr"> 651 </span>   <span class="Constant"> .c    .</span>
-<span id="L652" class="LineNr"> 652 </span><span class="Constant">    .╌╌╌╌╌.</span>
-<span id="L653" class="LineNr"> 653 </span>   <span class="Constant"> .     .</span>
+<span id="L649" class="LineNr"> 649 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L650" class="LineNr"> 650 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .efab↩.</span>
+<span id="L651" class="LineNr"> 651 </span>  <span class="Conceal">¦</span><span class="Constant"> .c    .</span>
+<span id="L652" class="LineNr"> 652 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌.</span>
+<span id="L653" class="LineNr"> 653 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
 <span id="L654" class="LineNr"> 654 </span>  ]
 <span id="L655" class="LineNr"> 655 </span>]
 <span id="L656" class="LineNr"> 656 </span>
@@ -725,76 +726,76 @@ if ('onhashchange' in window) {
 <span id="L664" class="LineNr"> 664 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L665" class="LineNr"> 665 </span>  <span class="Comment"># type more text at the start</span>
 <span id="L666" class="LineNr"> 666 </span>  assume-console [
-<span id="L667" class="LineNr"> 667 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L668" class="LineNr"> 668 </span>    type <span class="Constant">[abc]</span>
+<span id="L667" class="LineNr"> 667 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L668" class="LineNr"> 668 </span>  <span class="Conceal">¦</span> type <span class="Constant">[abc]</span>
 <span id="L669" class="LineNr"> 669 </span>  ]
 <span id="L670" class="LineNr"> 670 </span>  run [
-<span id="L671" class="LineNr"> 671 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L672" class="LineNr"> 672 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L673" class="LineNr"> 673 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L671" class="LineNr"> 671 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L672" class="LineNr"> 672 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L673" class="LineNr"> 673 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L674" class="LineNr"> 674 </span>  ]
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 <span id="L676" class="LineNr"> 676 </span>  memory-should-contain [
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-<span id="L678" class="LineNr"> 678 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L677" class="LineNr"> 677 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L678" class="LineNr"> 678 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
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-<span id="L683" class="LineNr"> 683 </span>   <span class="Constant"> .abcd↩     .</span>
-<span id="L684" class="LineNr"> 684 </span>   <span class="Constant"> .efg       .</span>
-<span id="L685" class="LineNr"> 685 </span>   <span class="Constant"> .abcd↩     .</span>
-<span id="L686" class="LineNr"> 686 </span>   <span class="Constant"> .efg       .</span>
+<span id="L682" class="LineNr"> 682 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L683" class="LineNr"> 683 </span>  <span class="Conceal">¦</span><span class="Constant"> .abcd↩     .</span>
+<span id="L684" class="LineNr"> 684 </span>  <span class="Conceal">¦</span><span class="Constant"> .efg       .</span>
+<span id="L685" class="LineNr"> 685 </span>  <span class="Conceal">¦</span><span class="Constant"> .abcd↩     .</span>
+<span id="L686" class="LineNr"> 686 </span>  <span class="Conceal">¦</span><span class="Constant"> .efg       .</span>
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 <span id="L689" class="LineNr"> 689 </span>
 <span id="L690" class="LineNr"> 690 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L217'>&lt;insert-character-special-case&gt;</a></span> [
 <span id="L691" class="LineNr"> 691 </span>  <span class="Comment"># if the line wraps at the cursor, move cursor to start of next row</span>
 <span id="L692" class="LineNr"> 692 </span>  <span class="Delimiter">{</span>
-<span id="L693" class="LineNr"> 693 </span>    <span class="Comment"># if either:</span>
-<span id="L694" class="LineNr"> 694 </span>    <span class="Comment"># a) we're at the end of the line and at the column of the wrap indicator, or</span>
-<span id="L695" class="LineNr"> 695 </span>    <span class="Comment"># b) we're not at end of line and just before the column of the wrap indicator</span>
-<span id="L696" class="LineNr"> 696 </span>    wrap-column:num <span class="Special">&lt;-</span> copy right
-<span id="L697" class="LineNr"> 697 </span>    before-wrap-column:num <span class="Special">&lt;-</span> subtract wrap-column,<span class="Constant"> 1</span>
-<span id="L698" class="LineNr"> 698 </span>    at-wrap?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-column, wrap-column
-<span id="L699" class="LineNr"> 699 </span>    just-before-wrap?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-column, before-wrap-column
-<span id="L700" class="LineNr"> 700 </span>    <a href='../065duplex_list.mu.html#L29'>next</a>:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
-<span id="L701" class="LineNr"> 701 </span>    <span class="Comment"># at end of line? next == 0 || next.value == 10/newline</span>
-<span id="L702" class="LineNr"> 702 </span>    at-end-of-line?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L29'>next</a>,<span class="Constant"> 0</span>
-<span id="L703" class="LineNr"> 703 </span>    <span class="Delimiter">{</span>
-<span id="L704" class="LineNr"> 704 </span>      <span class="muControl">break-if</span> at-end-of-line?
-<span id="L705" class="LineNr"> 705 </span>      next-character:char <span class="Special">&lt;-</span> get *next, <span class="Constant">value:offset</span>
-<span id="L706" class="LineNr"> 706 </span>      at-end-of-line? <span class="Special">&lt;-</span> equal next-character, <span class="Constant">10/newline</span>
-<span id="L707" class="LineNr"> 707 </span>    <span class="Delimiter">}</span>
-<span id="L708" class="LineNr"> 708 </span>    <span class="Comment"># break unless ((eol? and at-wrap?) or (~eol? and just-before-wrap?))</span>
-<span id="L709" class="LineNr"> 709 </span>    move-cursor-to-next-line?:bool <span class="Special">&lt;-</span> copy <span class="Constant">0/false</span>
-<span id="L710" class="LineNr"> 710 </span>    <span class="Delimiter">{</span>
-<span id="L711" class="LineNr"> 711 </span>      <span class="muControl">break-if</span> at-end-of-line?
-<span id="L712" class="LineNr"> 712 </span>      move-cursor-to-next-line? <span class="Special">&lt;-</span> copy just-before-wrap?
-<span id="L713" class="LineNr"> 713 </span>      <span class="Comment"># if we're moving the cursor because it's in the middle of a wrapping</span>
-<span id="L714" class="LineNr"> 714 </span>      <span class="Comment"># line, adjust it to left-most column</span>
-<span id="L715" class="LineNr"> 715 </span>      potential-new-cursor-column:num <span class="Special">&lt;-</span> copy left
-<span id="L716" class="LineNr"> 716 </span>    <span class="Delimiter">}</span>
-<span id="L717" class="LineNr"> 717 </span>    <span class="Delimiter">{</span>
-<span id="L718" class="LineNr"> 718 </span>      <span class="muControl">break-unless</span> at-end-of-line?
-<span id="L719" class="LineNr"> 719 </span>      move-cursor-to-next-line? <span class="Special">&lt;-</span> copy at-wrap?
-<span id="L720" class="LineNr"> 720 </span>      <span class="Comment"># if we're moving the cursor because it's at the end of a wrapping line,</span>
-<span id="L721" class="LineNr"> 721 </span>      <span class="Comment"># adjust it to one past the left-most column to make room for the</span>
-<span id="L722" class="LineNr"> 722 </span>      <span class="Comment"># newly-inserted wrap-indicator</span>
-<span id="L723" class="LineNr"> 723 </span>      potential-new-cursor-column:num <span class="Special">&lt;-</span> add left, <span class="Constant">1/make-room-for-wrap-indicator</span>
-<span id="L724" class="LineNr"> 724 </span>    <span class="Delimiter">}</span>
-<span id="L725" class="LineNr"> 725 </span>    <span class="muControl">break-unless</span> move-cursor-to-next-line?
-<span id="L726" class="LineNr"> 726 </span>    cursor-column <span class="Special">&lt;-</span> copy potential-new-cursor-column
-<span id="L727" class="LineNr"> 727 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
-<span id="L728" class="LineNr"> 728 </span>    cursor-row <span class="Special">&lt;-</span> add cursor-row,<span class="Constant"> 1</span>
-<span id="L729" class="LineNr"> 729 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
-<span id="L730" class="LineNr"> 730 </span>    <span class="Comment"># if we're out of the screen, scroll down</span>
-<span id="L731" class="LineNr"> 731 </span>    <span class="Delimiter">{</span>
-<span id="L732" class="LineNr"> 732 </span>      below-screen?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-row, <a href='../081print.mu.html#L594'>screen-height</a>
-<span id="L733" class="LineNr"> 733 </span>      <span class="muControl">break-unless</span> below-screen?
-<span id="L734" class="LineNr"> 734 </span><span class="Constant">      &lt;scroll-down&gt;</span>
-<span id="L735" class="LineNr"> 735 </span>    <span class="Delimiter">}</span>
-<span id="L736" class="LineNr"> 736 </span>    <span class="muControl">return</span> <span class="Constant">1/go-render</span>
+<span id="L693" class="LineNr"> 693 </span>  <span class="Conceal">¦</span> <span class="Comment"># if either:</span>
+<span id="L694" class="LineNr"> 694 </span>  <span class="Conceal">¦</span> <span class="Comment"># a) we're at the end of the line and at the column of the wrap indicator, or</span>
+<span id="L695" class="LineNr"> 695 </span>  <span class="Conceal">¦</span> <span class="Comment"># b) we're not at end of line and just before the column of the wrap indicator</span>
+<span id="L696" class="LineNr"> 696 </span>  <span class="Conceal">¦</span> wrap-column:num <span class="Special">&lt;-</span> copy right
+<span id="L697" class="LineNr"> 697 </span>  <span class="Conceal">¦</span> before-wrap-column:num <span class="Special">&lt;-</span> subtract wrap-column,<span class="Constant"> 1</span>
+<span id="L698" class="LineNr"> 698 </span>  <span class="Conceal">¦</span> at-wrap?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-column, wrap-column
+<span id="L699" class="LineNr"> 699 </span>  <span class="Conceal">¦</span> just-before-wrap?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-column, before-wrap-column
+<span id="L700" class="LineNr"> 700 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L29'>next</a>:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L701" class="LineNr"> 701 </span>  <span class="Conceal">¦</span> <span class="Comment"># at end of line? next == 0 || next.value == 10/newline</span>
+<span id="L702" class="LineNr"> 702 </span>  <span class="Conceal">¦</span> at-end-of-line?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L29'>next</a>,<span class="Constant"> 0</span>
+<span id="L703" class="LineNr"> 703 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L704" class="LineNr"> 704 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-end-of-line?
+<span id="L705" class="LineNr"> 705 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> next-character:char <span class="Special">&lt;-</span> get *next, <span class="Constant">value:offset</span>
+<span id="L706" class="LineNr"> 706 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-end-of-line? <span class="Special">&lt;-</span> equal next-character, <span class="Constant">10/newline</span>
+<span id="L707" class="LineNr"> 707 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L708" class="LineNr"> 708 </span>  <span class="Conceal">¦</span> <span class="Comment"># break unless ((eol? and at-wrap?) or (~eol? and just-before-wrap?))</span>
+<span id="L709" class="LineNr"> 709 </span>  <span class="Conceal">¦</span> move-cursor-to-next-line?:bool <span class="Special">&lt;-</span> copy <span class="Constant">0/false</span>
+<span id="L710" class="LineNr"> 710 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L711" class="LineNr"> 711 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-end-of-line?
+<span id="L712" class="LineNr"> 712 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> move-cursor-to-next-line? <span class="Special">&lt;-</span> copy just-before-wrap?
+<span id="L713" class="LineNr"> 713 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># if we're moving the cursor because it's in the middle of a wrapping</span>
+<span id="L714" class="LineNr"> 714 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># line, adjust it to left-most column</span>
+<span id="L715" class="LineNr"> 715 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> potential-new-cursor-column:num <span class="Special">&lt;-</span> copy left
+<span id="L716" class="LineNr"> 716 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L717" class="LineNr"> 717 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L718" class="LineNr"> 718 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-end-of-line?
+<span id="L719" class="LineNr"> 719 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> move-cursor-to-next-line? <span class="Special">&lt;-</span> copy at-wrap?
+<span id="L720" class="LineNr"> 720 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># if we're moving the cursor because it's at the end of a wrapping line,</span>
+<span id="L721" class="LineNr"> 721 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># adjust it to one past the left-most column to make room for the</span>
+<span id="L722" class="LineNr"> 722 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># newly-inserted wrap-indicator</span>
+<span id="L723" class="LineNr"> 723 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> potential-new-cursor-column:num <span class="Special">&lt;-</span> add left, <span class="Constant">1/make-room-for-wrap-indicator</span>
+<span id="L724" class="LineNr"> 724 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L725" class="LineNr"> 725 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> move-cursor-to-next-line?
+<span id="L726" class="LineNr"> 726 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> copy potential-new-cursor-column
+<span id="L727" class="LineNr"> 727 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
+<span id="L728" class="LineNr"> 728 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> add cursor-row,<span class="Constant"> 1</span>
+<span id="L729" class="LineNr"> 729 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
+<span id="L730" class="LineNr"> 730 </span>  <span class="Conceal">¦</span> <span class="Comment"># if we're out of the screen, scroll down</span>
+<span id="L731" class="LineNr"> 731 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L732" class="LineNr"> 732 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> below-screen?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-row, <a href='../081print.mu.html#L594'>screen-height</a>
+<span id="L733" class="LineNr"> 733 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> below-screen?
+<span id="L734" class="LineNr"> 734 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> &lt;scroll-down&gt;</span>
+<span id="L735" class="LineNr"> 735 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L736" class="LineNr"> 736 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">1/go-render</span>
 <span id="L737" class="LineNr"> 737 </span>  <span class="Delimiter">}</span>
 <span id="L738" class="LineNr"> 738 </span>]
 <span id="L739" class="LineNr"> 739 </span>
@@ -803,24 +804,24 @@ if ('onhashchange' in window) {
 <span id="L742" class="LineNr"> 742 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
 <span id="L743" class="LineNr"> 743 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> <span class="Constant">[abcde]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
 <span id="L744" class="LineNr"> 744 </span>  assume-console [
-<span id="L745" class="LineNr"> 745 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>  <span class="Comment"># right before the wrap icon</span>
-<span id="L746" class="LineNr"> 746 </span>    type <span class="Constant">[f]</span>
+<span id="L745" class="LineNr"> 745 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>  <span class="Comment"># right before the wrap icon</span>
+<span id="L746" class="LineNr"> 746 </span>  <span class="Conceal">¦</span> type <span class="Constant">[f]</span>
 <span id="L747" class="LineNr"> 747 </span>  ]
 <span id="L748" class="LineNr"> 748 </span>  run [
-<span id="L749" class="LineNr"> 749 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L750" class="LineNr"> 750 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L751" class="LineNr"> 751 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L749" class="LineNr"> 749 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L750" class="LineNr"> 750 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L751" class="LineNr"> 751 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L752" class="LineNr"> 752 </span>  ]
 <span id="L753" class="LineNr"> 753 </span>  screen-should-contain [
-<span id="L754" class="LineNr"> 754 </span>   <span class="Constant"> .          .</span>
-<span id="L755" class="LineNr"> 755 </span>   <span class="Constant"> .abcf↩     .</span>
-<span id="L756" class="LineNr"> 756 </span>   <span class="Constant"> .de        .</span>
-<span id="L757" class="LineNr"> 757 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
-<span id="L758" class="LineNr"> 758 </span>   <span class="Constant"> .          .</span>
+<span id="L754" class="LineNr"> 754 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L755" class="LineNr"> 755 </span>  <span class="Conceal">¦</span><span class="Constant"> .abcf↩     .</span>
+<span id="L756" class="LineNr"> 756 </span>  <span class="Conceal">¦</span><span class="Constant"> .de        .</span>
+<span id="L757" class="LineNr"> 757 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌     .</span>
+<span id="L758" class="LineNr"> 758 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L759" class="LineNr"> 759 </span>  ]
 <span id="L760" class="LineNr"> 760 </span>  memory-should-contain [
-<span id="L761" class="LineNr"> 761 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>  <span class="Comment"># cursor row</span>
-<span id="L762" class="LineNr"> 762 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># cursor column</span>
+<span id="L761" class="LineNr"> 761 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>  <span class="Comment"># cursor row</span>
+<span id="L762" class="LineNr"> 762 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># cursor column</span>
 <span id="L763" class="LineNr"> 763 </span>  ]
 <span id="L764" class="LineNr"> 764 </span>]
 <span id="L765" class="LineNr"> 765 </span>
@@ -833,25 +834,25 @@ if ('onhashchange' in window) {
 <span id="L772" class="LineNr"> 772 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
 <span id="L773" class="LineNr"> 773 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L774" class="LineNr"> 774 </span>  screen-should-contain [
-<span id="L775" class="LineNr"> 775 </span>   <span class="Constant"> .          .</span>
-<span id="L776" class="LineNr"> 776 </span>   <span class="Constant"> .abc       .</span>
-<span id="L777" class="LineNr"> 777 </span>   <span class="Constant"> .xyz       .</span>
-<span id="L778" class="LineNr"> 778 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
-<span id="L779" class="LineNr"> 779 </span>   <span class="Constant"> .          .</span>
+<span id="L775" class="LineNr"> 775 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L776" class="LineNr"> 776 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L777" class="LineNr"> 777 </span>  <span class="Conceal">¦</span><span class="Constant"> .xyz       .</span>
+<span id="L778" class="LineNr"> 778 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌     .</span>
+<span id="L779" class="LineNr"> 779 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L780" class="LineNr"> 780 </span>  ]
 <span id="L781" class="LineNr"> 781 </span>  assume-console [
-<span id="L782" class="LineNr"> 782 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 4</span>  <span class="Comment"># at end of first line</span>
-<span id="L783" class="LineNr"> 783 </span>    type <span class="Constant">[de]</span>  <span class="Comment"># trigger wrap</span>
+<span id="L782" class="LineNr"> 782 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 4</span>  <span class="Comment"># at end of first line</span>
+<span id="L783" class="LineNr"> 783 </span>  <span class="Conceal">¦</span> type <span class="Constant">[de]</span>  <span class="Comment"># trigger wrap</span>
 <span id="L784" class="LineNr"> 784 </span>  ]
 <span id="L785" class="LineNr"> 785 </span>  run [
-<span id="L786" class="LineNr"> 786 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L786" class="LineNr"> 786 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L787" class="LineNr"> 787 </span>  ]
 <span id="L788" class="LineNr"> 788 </span>  screen-should-contain [
-<span id="L789" class="LineNr"> 789 </span>   <span class="Constant"> .          .</span>
-<span id="L790" class="LineNr"> 790 </span>   <span class="Constant"> .abcd↩     .</span>
-<span id="L791" class="LineNr"> 791 </span>   <span class="Constant"> .e         .</span>
-<span id="L792" class="LineNr"> 792 </span>   <span class="Constant"> .xyz       .</span>
-<span id="L793" class="LineNr"> 793 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
+<span id="L789" class="LineNr"> 789 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L790" class="LineNr"> 790 </span>  <span class="Conceal">¦</span><span class="Constant"> .abcd↩     .</span>
+<span id="L791" class="LineNr"> 791 </span>  <span class="Conceal">¦</span><span class="Constant"> .e         .</span>
+<span id="L792" class="LineNr"> 792 </span>  <span class="Conceal">¦</span><span class="Constant"> .xyz       .</span>
+<span id="L793" class="LineNr"> 793 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌     .</span>
 <span id="L794" class="LineNr"> 794 </span>  ]
 <span id="L795" class="LineNr"> 795 </span>]
 <span id="L796" class="LineNr"> 796 </span>
@@ -860,24 +861,24 @@ if ('onhashchange' in window) {
 <span id="L799" class="LineNr"> 799 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
 <span id="L800" class="LineNr"> 800 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> <span class="Constant">[abcde]</span>, <span class="Constant">2/left</span>, <span class="Constant">7/right</span>
 <span id="L801" class="LineNr"> 801 </span>  assume-console [
-<span id="L802" class="LineNr"> 802 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 5</span>  <span class="Comment"># line is full; no wrap icon yet</span>
-<span id="L803" class="LineNr"> 803 </span>    type <span class="Constant">[01]</span>
+<span id="L802" class="LineNr"> 802 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 5</span>  <span class="Comment"># line is full; no wrap icon yet</span>
+<span id="L803" class="LineNr"> 803 </span>  <span class="Conceal">¦</span> type <span class="Constant">[01]</span>
 <span id="L804" class="LineNr"> 804 </span>  ]
 <span id="L805" class="LineNr"> 805 </span>  run [
-<span id="L806" class="LineNr"> 806 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L807" class="LineNr"> 807 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L808" class="LineNr"> 808 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L806" class="LineNr"> 806 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L807" class="LineNr"> 807 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L808" class="LineNr"> 808 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L809" class="LineNr"> 809 </span>  ]
 <span id="L810" class="LineNr"> 810 </span>  screen-should-contain [
-<span id="L811" class="LineNr"> 811 </span>   <span class="Constant"> .          .</span>
-<span id="L812" class="LineNr"> 812 </span>   <span class="Constant"> .  abc0↩   .</span>
-<span id="L813" class="LineNr"> 813 </span>   <span class="Constant"> .  1de     .</span>
-<span id="L814" class="LineNr"> 814 </span>   <span class="Constant"> .  ╌╌╌╌╌   .</span>
-<span id="L815" class="LineNr"> 815 </span>   <span class="Constant"> .          .</span>
+<span id="L811" class="LineNr"> 811 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L812" class="LineNr"> 812 </span>  <span class="Conceal">¦</span><span class="Constant"> .  abc0↩   .</span>
+<span id="L813" class="LineNr"> 813 </span>  <span class="Conceal">¦</span><span class="Constant"> .  1de     .</span>
+<span id="L814" class="LineNr"> 814 </span>  <span class="Conceal">¦</span><span class="Constant"> .  ╌╌╌╌╌   .</span>
+<span id="L815" class="LineNr"> 815 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L816" class="LineNr"> 816 </span>  ]
 <span id="L817" class="LineNr"> 817 </span>  memory-should-contain [
-<span id="L818" class="LineNr"> 818 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>  <span class="Comment"># cursor row</span>
-<span id="L819" class="LineNr"> 819 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>  <span class="Comment"># cursor column</span>
+<span id="L818" class="LineNr"> 818 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>  <span class="Comment"># cursor row</span>
+<span id="L819" class="LineNr"> 819 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>  <span class="Comment"># cursor column</span>
 <span id="L820" class="LineNr"> 820 </span>  ]
 <span id="L821" class="LineNr"> 821 </span>]
 <span id="L822" class="LineNr"> 822 </span>
@@ -896,29 +897,29 @@ if ('onhashchange' in window) {
 <span id="L835" class="LineNr"> 835 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
 <span id="L836" class="LineNr"> 836 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> <span class="Constant">[abc]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L837" class="LineNr"> 837 </span>  assume-console [
-<span id="L838" class="LineNr"> 838 </span>    type <span class="Constant">[0</span>
+<span id="L838" class="LineNr"> 838 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0</span>
 <span id="L839" class="LineNr"> 839 </span><span class="Constant">1]</span>
 <span id="L840" class="LineNr"> 840 </span>  ]
 <span id="L841" class="LineNr"> 841 </span>  run [
-<span id="L842" class="LineNr"> 842 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L842" class="LineNr"> 842 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L843" class="LineNr"> 843 </span>  ]
 <span id="L844" class="LineNr"> 844 </span>  screen-should-contain [
-<span id="L845" class="LineNr"> 845 </span>   <span class="Constant"> .          .</span>
-<span id="L846" class="LineNr"> 846 </span>   <span class="Constant"> .0         .</span>
-<span id="L847" class="LineNr"> 847 </span>   <span class="Constant"> .1abc      .</span>
-<span id="L848" class="LineNr"> 848 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L849" class="LineNr"> 849 </span>   <span class="Constant"> .          .</span>
+<span id="L845" class="LineNr"> 845 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L846" class="LineNr"> 846 </span>  <span class="Conceal">¦</span><span class="Constant"> .0         .</span>
+<span id="L847" class="LineNr"> 847 </span>  <span class="Conceal">¦</span><span class="Constant"> .1abc      .</span>
+<span id="L848" class="LineNr"> 848 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L849" class="LineNr"> 849 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L850" class="LineNr"> 850 </span>  ]
 <span id="L851" class="LineNr"> 851 </span>]
 <span id="L852" class="LineNr"> 852 </span>
 <span id="L853" class="LineNr"> 853 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L183'>&lt;handle-special-character&gt;</a></span> [
 <span id="L854" class="LineNr"> 854 </span>  <span class="Delimiter">{</span>
-<span id="L855" class="LineNr"> 855 </span>    newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
-<span id="L856" class="LineNr"> 856 </span>    <span class="muControl">break-unless</span> newline?
-<span id="L857" class="LineNr"> 857 </span><span class="Constant">    <a href='002-typing.mu.html#L857'>&lt;insert-enter-begin&gt;</a></span>
-<span id="L858" class="LineNr"> 858 </span>    <a href='002-typing.mu.html#L864'>insert-new-line-and-indent</a> editor, <a href='../081print.mu.html#L4'>screen</a>
-<span id="L859" class="LineNr"> 859 </span><span class="Constant">    <a href='002-typing.mu.html#L859'>&lt;insert-enter-end&gt;</a></span>
-<span id="L860" class="LineNr"> 860 </span>    <span class="muControl">return</span> <span class="Constant">1/go-render</span>
+<span id="L855" class="LineNr"> 855 </span>  <span class="Conceal">¦</span> newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
+<span id="L856" class="LineNr"> 856 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> newline?
+<span id="L857" class="LineNr"> 857 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> <a href='002-typing.mu.html#L857'>&lt;insert-enter-begin&gt;</a></span>
+<span id="L858" class="LineNr"> 858 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L864'>insert-new-line-and-indent</a> editor, <a href='../081print.mu.html#L4'>screen</a>
+<span id="L859" class="LineNr"> 859 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> <a href='002-typing.mu.html#L859'>&lt;insert-enter-end&gt;</a></span>
+<span id="L860" class="LineNr"> 860 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">1/go-render</span>
 <span id="L861" class="LineNr"> 861 </span>  <span class="Delimiter">}</span>
 <span id="L862" class="LineNr"> 862 </span>]
 <span id="L863" class="LineNr"> 863 </span>
@@ -941,11 +942,11 @@ if ('onhashchange' in window) {
 <span id="L880" class="LineNr"> 880 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
 <span id="L881" class="LineNr"> 881 </span>  <span class="Comment"># maybe scroll</span>
 <span id="L882" class="LineNr"> 882 </span>  <span class="Delimiter">{</span>
-<span id="L883" class="LineNr"> 883 </span>    below-screen?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-row, <a href='../081print.mu.html#L594'>screen-height</a>  <span class="Comment"># must be equal, never greater</span>
-<span id="L884" class="LineNr"> 884 </span>    <span class="muControl">break-unless</span> below-screen?
-<span id="L885" class="LineNr"> 885 </span><span class="Constant">    &lt;scroll-down&gt;</span>
-<span id="L886" class="LineNr"> 886 </span>    cursor-row <span class="Special">&lt;-</span> subtract cursor-row,<span class="Constant"> 1</span>  <span class="Comment"># bring back into screen range</span>
-<span id="L887" class="LineNr"> 887 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
+<span id="L883" class="LineNr"> 883 </span>  <span class="Conceal">¦</span> below-screen?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-row, <a href='../081print.mu.html#L594'>screen-height</a>  <span class="Comment"># must be equal, never greater</span>
+<span id="L884" class="LineNr"> 884 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> below-screen?
+<span id="L885" class="LineNr"> 885 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;scroll-down&gt;</span>
+<span id="L886" class="LineNr"> 886 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> subtract cursor-row,<span class="Constant"> 1</span>  <span class="Comment"># bring back into screen range</span>
+<span id="L887" class="LineNr"> 887 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
 <span id="L888" class="LineNr"> 888 </span>  <span class="Delimiter">}</span>
 <span id="L889" class="LineNr"> 889 </span>  <span class="Comment"># indent if necessary</span>
 <span id="L890" class="LineNr"> 890 </span>  indent?:bool <span class="Special">&lt;-</span> get *editor, <span class="Constant">indent?:offset</span>
@@ -955,11 +956,11 @@ if ('onhashchange' in window) {
 <span id="L894" class="LineNr"> 894 </span>  indent:num <span class="Special">&lt;-</span> <a href='002-typing.mu.html#L907'>line-indent</a> end-of-previous-line, d
 <span id="L895" class="LineNr"> 895 </span>  i:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
 <span id="L896" class="LineNr"> 896 </span>  <span class="Delimiter">{</span>
-<span id="L897" class="LineNr"> 897 </span>    indent-done?:bool <span class="Special">&lt;-</span> greater-or-equal i, indent
-<span id="L898" class="LineNr"> 898 </span>    <span class="muControl">break-if</span> indent-done?
-<span id="L899" class="LineNr"> 899 </span>    <a href='002-typing.mu.html#L201'>insert-at-cursor</a> editor, <span class="Constant">32/space</span>, <a href='../081print.mu.html#L4'>screen</a>
-<span id="L900" class="LineNr"> 900 </span>    i <span class="Special">&lt;-</span> add i,<span class="Constant"> 1</span>
-<span id="L901" class="LineNr"> 901 </span>    <span class="muControl">loop</span>
+<span id="L897" class="LineNr"> 897 </span>  <span class="Conceal">¦</span> indent-done?:bool <span class="Special">&lt;-</span> greater-or-equal i, indent
+<span id="L898" class="LineNr"> 898 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> indent-done?
+<span id="L899" class="LineNr"> 899 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L201'>insert-at-cursor</a> editor, <span class="Constant">32/space</span>, <a href='../081print.mu.html#L4'>screen</a>
+<span id="L900" class="LineNr"> 900 </span>  <span class="Conceal">¦</span> i <span class="Special">&lt;-</span> add i,<span class="Constant"> 1</span>
+<span id="L901" class="LineNr"> 901 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L902" class="LineNr"> 902 </span>  <span class="Delimiter">}</span>
 <span id="L903" class="LineNr"> 903 </span>]
 <span id="L904" class="LineNr"> 904 </span>
@@ -973,25 +974,25 @@ if ('onhashchange' in window) {
 <span id="L912" class="LineNr"> 912 </span>  at-start?:bool <span class="Special">&lt;-</span> equal curr, start
 <span id="L913" class="LineNr"> 913 </span>  <span class="muControl">return-if</span> at-start?
 <span id="L914" class="LineNr"> 914 </span>  <span class="Delimiter">{</span>
-<span id="L915" class="LineNr"> 915 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> curr
-<span id="L916" class="LineNr"> 916 </span>    <span class="muControl">break-unless</span> curr
-<span id="L917" class="LineNr"> 917 </span>    at-start?:bool <span class="Special">&lt;-</span> equal curr, start
-<span id="L918" class="LineNr"> 918 </span>    <span class="muControl">break-if</span> at-start?
-<span id="L919" class="LineNr"> 919 </span>    c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
-<span id="L920" class="LineNr"> 920 </span>    at-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
-<span id="L921" class="LineNr"> 921 </span>    <span class="muControl">break-if</span> at-newline?
-<span id="L922" class="LineNr"> 922 </span>    <span class="Comment"># if c is a space, increment result</span>
-<span id="L923" class="LineNr"> 923 </span>    is-space?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">32/space</span>
-<span id="L924" class="LineNr"> 924 </span>    <span class="Delimiter">{</span>
-<span id="L925" class="LineNr"> 925 </span>      <span class="muControl">break-unless</span> is-space?
-<span id="L926" class="LineNr"> 926 </span>      result <span class="Special">&lt;-</span> add result,<span class="Constant"> 1</span>
-<span id="L927" class="LineNr"> 927 </span>    <span class="Delimiter">}</span>
-<span id="L928" class="LineNr"> 928 </span>    <span class="Comment"># if c is not a space, reset result</span>
-<span id="L929" class="LineNr"> 929 </span>    <span class="Delimiter">{</span>
-<span id="L930" class="LineNr"> 930 </span>      <span class="muControl">break-if</span> is-space?
-<span id="L931" class="LineNr"> 931 </span>      result <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
-<span id="L932" class="LineNr"> 932 </span>    <span class="Delimiter">}</span>
-<span id="L933" class="LineNr"> 933 </span>    <span class="muControl">loop</span>
+<span id="L915" class="LineNr"> 915 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> curr
+<span id="L916" class="LineNr"> 916 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> curr
+<span id="L917" class="LineNr"> 917 </span>  <span class="Conceal">¦</span> at-start?:bool <span class="Special">&lt;-</span> equal curr, start
+<span id="L918" class="LineNr"> 918 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-start?
+<span id="L919" class="LineNr"> 919 </span>  <span class="Conceal">¦</span> c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
+<span id="L920" class="LineNr"> 920 </span>  <span class="Conceal">¦</span> at-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
+<span id="L921" class="LineNr"> 921 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-newline?
+<span id="L922" class="LineNr"> 922 </span>  <span class="Conceal">¦</span> <span class="Comment"># if c is a space, increment result</span>
+<span id="L923" class="LineNr"> 923 </span>  <span class="Conceal">¦</span> is-space?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">32/space</span>
+<span id="L924" class="LineNr"> 924 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L925" class="LineNr"> 925 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-space?
+<span id="L926" class="LineNr"> 926 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> result <span class="Special">&lt;-</span> add result,<span class="Constant"> 1</span>
+<span id="L927" class="LineNr"> 927 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L928" class="LineNr"> 928 </span>  <span class="Conceal">¦</span> <span class="Comment"># if c is not a space, reset result</span>
+<span id="L929" class="LineNr"> 929 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L930" class="LineNr"> 930 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> is-space?
+<span id="L931" class="LineNr"> 931 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> result <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
+<span id="L932" class="LineNr"> 932 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L933" class="LineNr"> 933 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L934" class="LineNr"> 934 </span>  <span class="Delimiter">}</span>
 <span id="L935" class="LineNr"> 935 </span>]
 <span id="L936" class="LineNr"> 936 </span>
@@ -1000,18 +1001,18 @@ if ('onhashchange' in window) {
 <span id="L939" class="LineNr"> 939 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
 <span id="L940" class="LineNr"> 940 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> <span class="Constant">[abc]</span>, <span class="Constant">1/left</span>, <span class="Constant">10/right</span>
 <span id="L941" class="LineNr"> 941 </span>  assume-console [
-<span id="L942" class="LineNr"> 942 </span>    type <span class="Constant">[0</span>
+<span id="L942" class="LineNr"> 942 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0</span>
 <span id="L943" class="LineNr"> 943 </span><span class="Constant">1]</span>
 <span id="L944" class="LineNr"> 944 </span>  ]
 <span id="L945" class="LineNr"> 945 </span>  run [
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+<span id="L946" class="LineNr"> 946 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
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 <span id="L948" class="LineNr"> 948 </span>  screen-should-contain [
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-<span id="L950" class="LineNr"> 950 </span>   <span class="Constant"> . 0        .</span>
-<span id="L951" class="LineNr"> 951 </span>   <span class="Constant"> . 1abc     .</span>
-<span id="L952" class="LineNr"> 952 </span>   <span class="Constant"> . ╌╌╌╌╌╌╌╌╌.</span>
-<span id="L953" class="LineNr"> 953 </span>   <span class="Constant"> .          .</span>
+<span id="L949" class="LineNr"> 949 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L950" class="LineNr"> 950 </span>  <span class="Conceal">¦</span><span class="Constant"> . 0        .</span>
+<span id="L951" class="LineNr"> 951 </span>  <span class="Conceal">¦</span><span class="Constant"> . 1abc     .</span>
+<span id="L952" class="LineNr"> 952 </span>  <span class="Conceal">¦</span><span class="Constant"> . ╌╌╌╌╌╌╌╌╌.</span>
+<span id="L953" class="LineNr"> 953 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L954" class="LineNr"> 954 </span>  ]
 <span id="L955" class="LineNr"> 955 </span>]
 <span id="L956" class="LineNr"> 956 </span>
@@ -1021,25 +1022,25 @@ if ('onhashchange' in window) {
 <span id="L960" class="LineNr"> 960 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> <span class="Constant">[abcde]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
 <span id="L961" class="LineNr"> 961 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L962" class="LineNr"> 962 </span>  screen-should-contain [
-<span id="L963" class="LineNr"> 963 </span>   <span class="Constant"> .          .</span>
-<span id="L964" class="LineNr"> 964 </span>   <span class="Constant"> .abcd↩     .</span>
-<span id="L965" class="LineNr"> 965 </span>   <span class="Constant"> .e         .</span>
-<span id="L966" class="LineNr"> 966 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
-<span id="L967" class="LineNr"> 967 </span>   <span class="Constant"> .          .</span>
+<span id="L963" class="LineNr"> 963 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L964" class="LineNr"> 964 </span>  <span class="Conceal">¦</span><span class="Constant"> .abcd↩     .</span>
+<span id="L965" class="LineNr"> 965 </span>  <span class="Conceal">¦</span><span class="Constant"> .e         .</span>
+<span id="L966" class="LineNr"> 966 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌     .</span>
+<span id="L967" class="LineNr"> 967 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L968" class="LineNr"> 968 </span>  ]
 <span id="L969" class="LineNr"> 969 </span>  assume-console [
-<span id="L970" class="LineNr"> 970 </span>    press enter
+<span id="L970" class="LineNr"> 970 </span>  <span class="Conceal">¦</span> press enter
 <span id="L971" class="LineNr"> 971 </span>  ]
 <span id="L972" class="LineNr"> 972 </span>  run [
-<span id="L973" class="LineNr"> 973 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L973" class="LineNr"> 973 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L974" class="LineNr"> 974 </span>  ]
 <span id="L975" class="LineNr"> 975 </span>  <span class="Comment"># line should be fully cleared</span>
 <span id="L976" class="LineNr"> 976 </span>  screen-should-contain [
-<span id="L977" class="LineNr"> 977 </span>   <span class="Constant"> .          .</span>
-<span id="L978" class="LineNr"> 978 </span>   <span class="Constant"> .          .</span>
-<span id="L979" class="LineNr"> 979 </span>   <span class="Constant"> .abcd↩     .</span>
-<span id="L980" class="LineNr"> 980 </span>   <span class="Constant"> .e         .</span>
-<span id="L981" class="LineNr"> 981 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
+<span id="L977" class="LineNr"> 977 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L978" class="LineNr"> 978 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L979" class="LineNr"> 979 </span>  <span class="Conceal">¦</span><span class="Constant"> .abcd↩     .</span>
+<span id="L980" class="LineNr"> 980 </span>  <span class="Conceal">¦</span><span class="Constant"> .e         .</span>
+<span id="L981" class="LineNr"> 981 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌     .</span>
 <span id="L982" class="LineNr"> 982 </span>  ]
 <span id="L983" class="LineNr"> 983 </span>]
 <span id="L984" class="LineNr"> 984 </span>
@@ -1052,19 +1053,19 @@ if ('onhashchange' in window) {
 <span id="L991" class="LineNr"> 991 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L992" class="LineNr"> 992 </span>  <span class="Comment"># position cursor after 'cd' and hit 'newline'</span>
 <span id="L993" class="LineNr"> 993 </span>  assume-console [
-<span id="L994" class="LineNr"> 994 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 8</span>
-<span id="L995" class="LineNr"> 995 </span>    type [
+<span id="L994" class="LineNr"> 994 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 8</span>
+<span id="L995" class="LineNr"> 995 </span>  <span class="Conceal">¦</span> type [
 <span id="L996" class="LineNr"> 996 </span>]
 <span id="L997" class="LineNr"> 997 </span>  ]
 <span id="L998" class="LineNr"> 998 </span>  run [
-<span id="L999" class="LineNr"> 999 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L1000" class="LineNr">1000 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L1001" class="LineNr">1001 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L999" class="LineNr"> 999 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1000" class="LineNr">1000 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L1001" class="LineNr">1001 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1002" class="LineNr">1002 </span>  ]
 <span id="L1003" class="LineNr">1003 </span>  <span class="Comment"># cursor should be below start of previous line</span>
 <span id="L1004" class="LineNr">1004 </span>  memory-should-contain [
-<span id="L1005" class="LineNr">1005 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>  <span class="Comment"># cursor row</span>
-<span id="L1006" class="LineNr">1006 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>  <span class="Comment"># cursor column (indented)</span>
+<span id="L1005" class="LineNr">1005 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>  <span class="Comment"># cursor row</span>
+<span id="L1006" class="LineNr">1006 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>  <span class="Comment"># cursor column (indented)</span>
 <span id="L1007" class="LineNr">1007 </span>  ]
 <span id="L1008" class="LineNr">1008 </span>]
 <span id="L1009" class="LineNr">1009 </span>
@@ -1077,38 +1078,38 @@ if ('onhashchange' in window) {
 <span id="L1016" class="LineNr">1016 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L1017" class="LineNr">1017 </span>  <span class="Comment"># position cursor after 'cd' and hit 'newline' surrounded by paste markers</span>
 <span id="L1018" class="LineNr">1018 </span>  assume-console [
-<span id="L1019" class="LineNr">1019 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 8</span>
-<span id="L1020" class="LineNr">1020 </span>    press<span class="Constant"> 65507</span>  <span class="Comment"># start paste</span>
-<span id="L1021" class="LineNr">1021 </span>    press enter
-<span id="L1022" class="LineNr">1022 </span>    press<span class="Constant"> 65506</span>  <span class="Comment"># end paste</span>
+<span id="L1019" class="LineNr">1019 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 8</span>
+<span id="L1020" class="LineNr">1020 </span>  <span class="Conceal">¦</span> press<span class="Constant"> 65507</span>  <span class="Comment"># start paste</span>
+<span id="L1021" class="LineNr">1021 </span>  <span class="Conceal">¦</span> press enter
+<span id="L1022" class="LineNr">1022 </span>  <span class="Conceal">¦</span> press<span class="Constant"> 65506</span>  <span class="Comment"># end paste</span>
 <span id="L1023" class="LineNr">1023 </span>  ]
 <span id="L1024" class="LineNr">1024 </span>  run [
-<span id="L1025" class="LineNr">1025 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L1026" class="LineNr">1026 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L1027" class="LineNr">1027 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L1025" class="LineNr">1025 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1026" class="LineNr">1026 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L1027" class="LineNr">1027 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1028" class="LineNr">1028 </span>  ]
 <span id="L1029" class="LineNr">1029 </span>  <span class="Comment"># cursor should be below start of previous line</span>
 <span id="L1030" class="LineNr">1030 </span>  memory-should-contain [
-<span id="L1031" class="LineNr">1031 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>  <span class="Comment"># cursor row</span>
-<span id="L1032" class="LineNr">1032 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># cursor column (not indented)</span>
+<span id="L1031" class="LineNr">1031 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>  <span class="Comment"># cursor row</span>
+<span id="L1032" class="LineNr">1032 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># cursor column (not indented)</span>
 <span id="L1033" class="LineNr">1033 </span>  ]
 <span id="L1034" class="LineNr">1034 </span>]
 <span id="L1035" class="LineNr">1035 </span>
 <span id="L1036" class="LineNr">1036 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L197'>&lt;handle-special-key&gt;</a></span> [
 <span id="L1037" class="LineNr">1037 </span>  <span class="Delimiter">{</span>
-<span id="L1038" class="LineNr">1038 </span>    paste-start?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65507/paste-start</span>
-<span id="L1039" class="LineNr">1039 </span>    <span class="muControl">break-unless</span> paste-start?
-<span id="L1040" class="LineNr">1040 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">indent?:offset</span>, <span class="Constant">0/false</span>
-<span id="L1041" class="LineNr">1041 </span>    <span class="muControl">return</span> <span class="Constant">1/go-render</span>
+<span id="L1038" class="LineNr">1038 </span>  <span class="Conceal">¦</span> paste-start?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65507/paste-start</span>
+<span id="L1039" class="LineNr">1039 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> paste-start?
+<span id="L1040" class="LineNr">1040 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">indent?:offset</span>, <span class="Constant">0/false</span>
+<span id="L1041" class="LineNr">1041 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">1/go-render</span>
 <span id="L1042" class="LineNr">1042 </span>  <span class="Delimiter">}</span>
 <span id="L1043" class="LineNr">1043 </span>]
 <span id="L1044" class="LineNr">1044 </span>
 <span id="L1045" class="LineNr">1045 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L197'>&lt;handle-special-key&gt;</a></span> [
 <span id="L1046" class="LineNr">1046 </span>  <span class="Delimiter">{</span>
-<span id="L1047" class="LineNr">1047 </span>    paste-end?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65506/paste-end</span>
-<span id="L1048" class="LineNr">1048 </span>    <span class="muControl">break-unless</span> paste-end?
-<span id="L1049" class="LineNr">1049 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">indent?:offset</span>, <span class="Constant">1/true</span>
-<span id="L1050" class="LineNr">1050 </span>    <span class="muControl">return</span> <span class="Constant">1/go-render</span>
+<span id="L1047" class="LineNr">1047 </span>  <span class="Conceal">¦</span> paste-end?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65506/paste-end</span>
+<span id="L1048" class="LineNr">1048 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> paste-end?
+<span id="L1049" class="LineNr">1049 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">indent?:offset</span>, <span class="Constant">1/true</span>
+<span id="L1050" class="LineNr">1050 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">1/go-render</span>
 <span id="L1051" class="LineNr">1051 </span>  <span class="Delimiter">}</span>
 <span id="L1052" class="LineNr">1052 </span>]
 <span id="L1053" class="LineNr">1053 </span>
@@ -1119,27 +1120,27 @@ if ('onhashchange' in window) {
 <span id="L1058" class="LineNr">1058 </span>  <span class="Constant">load-ingredients</span>
 <span id="L1059" class="LineNr">1059 </span>  style:char, style-found?:bool <span class="Special">&lt;-</span> <span class="Constant">next-ingredient</span>
 <span id="L1060" class="LineNr">1060 </span>  <span class="Delimiter">{</span>
-<span id="L1061" class="LineNr">1061 </span>    <span class="muControl">break-if</span> style-found?
-<span id="L1062" class="LineNr">1062 </span>    style <span class="Special">&lt;-</span> copy <span class="Constant">9472/horizontal</span>
+<span id="L1061" class="LineNr">1061 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> style-found?
+<span id="L1062" class="LineNr">1062 </span>  <span class="Conceal">¦</span> style <span class="Special">&lt;-</span> copy <span class="Constant">9472/horizontal</span>
 <span id="L1063" class="LineNr">1063 </span>  <span class="Delimiter">}</span>
 <span id="L1064" class="LineNr">1064 </span>  color:num, color-found?:bool <span class="Special">&lt;-</span> <span class="Constant">next-ingredient</span>
 <span id="L1065" class="LineNr">1065 </span>  <span class="Delimiter">{</span>
-<span id="L1066" class="LineNr">1066 </span>    <span class="Comment"># default color to white</span>
-<span id="L1067" class="LineNr">1067 </span>    <span class="muControl">break-if</span> color-found?
-<span id="L1068" class="LineNr">1068 </span>    color <span class="Special">&lt;-</span> copy <span class="Constant">245/grey</span>
+<span id="L1066" class="LineNr">1066 </span>  <span class="Conceal">¦</span> <span class="Comment"># default color to white</span>
+<span id="L1067" class="LineNr">1067 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> color-found?
+<span id="L1068" class="LineNr">1068 </span>  <span class="Conceal">¦</span> color <span class="Special">&lt;-</span> copy <span class="Constant">245/grey</span>
 <span id="L1069" class="LineNr">1069 </span>  <span class="Delimiter">}</span>
 <span id="L1070" class="LineNr">1070 </span>  bg-color:num, bg-color-found?:bool <span class="Special">&lt;-</span> <span class="Constant">next-ingredient</span>
 <span id="L1071" class="LineNr">1071 </span>  <span class="Delimiter">{</span>
-<span id="L1072" class="LineNr">1072 </span>    <span class="muControl">break-if</span> bg-color-found?
-<span id="L1073" class="LineNr">1073 </span>    bg-color <span class="Special">&lt;-</span> copy <span class="Constant">0/black</span>
+<span id="L1072" class="LineNr">1072 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> bg-color-found?
+<span id="L1073" class="LineNr">1073 </span>  <span class="Conceal">¦</span> bg-color <span class="Special">&lt;-</span> copy <span class="Constant">0/black</span>
 <span id="L1074" class="LineNr">1074 </span>  <span class="Delimiter">}</span>
 <span id="L1075" class="LineNr">1075 </span>  <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, x
 <span id="L1076" class="LineNr">1076 </span>  <span class="Delimiter">{</span>
-<span id="L1077" class="LineNr">1077 </span>    continue?:bool <span class="Special">&lt;-</span> lesser-or-equal x, right  <span class="Comment"># right is inclusive, to match editor semantics</span>
-<span id="L1078" class="LineNr">1078 </span>    <span class="muControl">break-unless</span> continue?
-<span id="L1079" class="LineNr">1079 </span>    print <a href='../081print.mu.html#L4'>screen</a>, style, color, bg-color
-<span id="L1080" class="LineNr">1080 </span>    x <span class="Special">&lt;-</span> add x,<span class="Constant"> 1</span>
-<span id="L1081" class="LineNr">1081 </span>    <span class="muControl">loop</span>
+<span id="L1077" class="LineNr">1077 </span>  <span class="Conceal">¦</span> continue?:bool <span class="Special">&lt;-</span> lesser-or-equal x, right  <span class="Comment"># right is inclusive, to match editor semantics</span>
+<span id="L1078" class="LineNr">1078 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> continue?
+<span id="L1079" class="LineNr">1079 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, style, color, bg-color
+<span id="L1080" class="LineNr">1080 </span>  <span class="Conceal">¦</span> x <span class="Special">&lt;-</span> add x,<span class="Constant"> 1</span>
+<span id="L1081" class="LineNr">1081 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L1082" class="LineNr">1082 </span>  <span class="Delimiter">}</span>
 <span id="L1083" class="LineNr">1083 </span>]
 </pre>
diff --git a/html/edit/003-shortcuts.mu.html b/html/edit/003-shortcuts.mu.html
index 0881417f..2220376e 100644
--- a/html/edit/003-shortcuts.mu.html
+++ b/html/edit/003-shortcuts.mu.html
@@ -15,15 +15,16 @@ body { font-size: 12pt; font-family: monospace; color: #eeeeee; background-color
 a { text-decoration: none; }
 a:hover { text-decoration: underline; }
 * { font-size: 12pt; font-size: 1em; }
-.Delimiter { color: #800080; }
-.muControl { color: #c0a020; }
+.Conceal { color: #4e4e4e; }
+.muScenario { color: #00af00; }
 .Special { color: #c00000; }
+.Delimiter { color: #800080; }
 .SalientComment { color: #00ffff; }
 .Constant { color: #00a0a0; }
 .LineNr { color: #444444; }
-.Comment { color: #9090ff; }
 .muRecipe { color: #ff8700; }
-.muScenario { color: #00af00; }
+.Comment { color: #9090ff; }
+.muControl { color: #c0a020; }
 -->
 </style>
 
@@ -72,27 +73,27 @@ if ('onhashchange' in window) {
 <span id="L12" class="LineNr">  12 </span><span class="Constant">cd]</span>
 <span id="L13" class="LineNr">  13 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
 <span id="L14" class="LineNr">  14 </span>  assume-console [
-<span id="L15" class="LineNr">  15 </span>    press tab
+<span id="L15" class="LineNr">  15 </span>  <span class="Conceal">¦</span> press tab
 <span id="L16" class="LineNr">  16 </span>  ]
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-<span id="L18" class="LineNr">  18 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L18" class="LineNr">  18 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L19" class="LineNr">  19 </span>  ]
 <span id="L20" class="LineNr">  20 </span>  screen-should-contain [
-<span id="L21" class="LineNr">  21 </span>   <span class="Constant"> .          .</span>
-<span id="L22" class="LineNr">  22 </span>   <span class="Constant"> .  ab      .</span>
-<span id="L23" class="LineNr">  23 </span>   <span class="Constant"> .cd        .</span>
+<span id="L21" class="LineNr">  21 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L22" class="LineNr">  22 </span>  <span class="Conceal">¦</span><span class="Constant"> .  ab      .</span>
+<span id="L23" class="LineNr">  23 </span>  <span class="Conceal">¦</span><span class="Constant"> .cd        .</span>
 <span id="L24" class="LineNr">  24 </span>  ]
 <span id="L25" class="LineNr">  25 </span>]
 <span id="L26" class="LineNr">  26 </span>
 <span id="L27" class="LineNr">  27 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L183'>&lt;handle-special-character&gt;</a></span> [
 <span id="L28" class="LineNr">  28 </span>  <span class="Delimiter">{</span>
-<span id="L29" class="LineNr">  29 </span>    tab?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">9/tab</span>
-<span id="L30" class="LineNr">  30 </span>    <span class="muControl">break-unless</span> tab?
-<span id="L31" class="LineNr">  31 </span><span class="Constant">    &lt;insert-character-begin&gt;</span>
-<span id="L32" class="LineNr">  32 </span>    <a href='002-typing.mu.html#L201'>insert-at-cursor</a> editor, <span class="Constant">32/space</span>, <a href='../081print.mu.html#L4'>screen</a>
-<span id="L33" class="LineNr">  33 </span>    <a href='002-typing.mu.html#L201'>insert-at-cursor</a> editor, <span class="Constant">32/space</span>, <a href='../081print.mu.html#L4'>screen</a>
-<span id="L34" class="LineNr">  34 </span><span class="Constant">    &lt;insert-character-end&gt;</span>
-<span id="L35" class="LineNr">  35 </span>    <span class="muControl">return</span> <span class="Constant">1/go-render</span>
+<span id="L29" class="LineNr">  29 </span>  <span class="Conceal">¦</span> tab?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">9/tab</span>
+<span id="L30" class="LineNr">  30 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> tab?
+<span id="L31" class="LineNr">  31 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;insert-character-begin&gt;</span>
+<span id="L32" class="LineNr">  32 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L201'>insert-at-cursor</a> editor, <span class="Constant">32/space</span>, <a href='../081print.mu.html#L4'>screen</a>
+<span id="L33" class="LineNr">  33 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L201'>insert-at-cursor</a> editor, <span class="Constant">32/space</span>, <a href='../081print.mu.html#L4'>screen</a>
+<span id="L34" class="LineNr">  34 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;insert-character-end&gt;</span>
+<span id="L35" class="LineNr">  35 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">1/go-render</span>
 <span id="L36" class="LineNr">  36 </span>  <span class="Delimiter">}</span>
 <span id="L37" class="LineNr">  37 </span>]
 <span id="L38" class="LineNr">  38 </span>
@@ -105,35 +106,35 @@ if ('onhashchange' in window) {
 <span id="L45" class="LineNr">  45 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L46" class="LineNr">  46 </span>  $clear-trace
 <span id="L47" class="LineNr">  47 </span>  assume-console [
-<span id="L48" class="LineNr">  48 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
-<span id="L49" class="LineNr">  49 </span>    press backspace
+<span id="L48" class="LineNr">  48 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
+<span id="L49" class="LineNr">  49 </span>  <span class="Conceal">¦</span> press backspace
 <span id="L50" class="LineNr">  50 </span>  ]
 <span id="L51" class="LineNr">  51 </span>  run [
-<span id="L52" class="LineNr">  52 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L53" class="LineNr">  53 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L54" class="LineNr">  54 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L52" class="LineNr">  52 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L53" class="LineNr">  53 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L54" class="LineNr">  54 </span>  <span class="Conceal">¦</span> 5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L55" class="LineNr">  55 </span>  ]
 <span id="L56" class="LineNr">  56 </span>  screen-should-contain [
-<span id="L57" class="LineNr">  57 </span>   <span class="Constant"> .          .</span>
-<span id="L58" class="LineNr">  58 </span>   <span class="Constant"> .bc        .</span>
-<span id="L59" class="LineNr">  59 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L60" class="LineNr">  60 </span>   <span class="Constant"> .          .</span>
+<span id="L57" class="LineNr">  57 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L58" class="LineNr">  58 </span>  <span class="Conceal">¦</span><span class="Constant"> .bc        .</span>
+<span id="L59" class="LineNr">  59 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L60" class="LineNr">  60 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L61" class="LineNr">  61 </span>  ]
 <span id="L62" class="LineNr">  62 </span>  memory-should-contain [
-<span id="L63" class="LineNr">  63 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L64" class="LineNr">  64 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
+<span id="L63" class="LineNr">  63 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L64" class="LineNr">  64 </span>  <span class="Conceal">¦</span><span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
 <span id="L65" class="LineNr">  65 </span>  ]
 <span id="L66" class="LineNr">  66 </span>  check-trace-count-for-label<span class="Constant"> 3</span>, <span class="Constant">[print-character]</span>  <span class="Comment"># length of original line to overwrite</span>
 <span id="L67" class="LineNr">  67 </span>]
 <span id="L68" class="LineNr">  68 </span>
 <span id="L69" class="LineNr">  69 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L183'>&lt;handle-special-character&gt;</a></span> [
 <span id="L70" class="LineNr">  70 </span>  <span class="Delimiter">{</span>
-<span id="L71" class="LineNr">  71 </span>    delete-previous-character?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">8/backspace</span>
-<span id="L72" class="LineNr">  72 </span>    <span class="muControl">break-unless</span> delete-previous-character?
-<span id="L73" class="LineNr">  73 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L73'>&lt;backspace-character-begin&gt;</a></span>
-<span id="L74" class="LineNr">  74 </span>    go-render?:bool, backspaced-cell:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L83'>delete-before-cursor</a> editor, <a href='../081print.mu.html#L4'>screen</a>
-<span id="L75" class="LineNr">  75 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L75'>&lt;backspace-character-end&gt;</a></span>
-<span id="L76" class="LineNr">  76 </span>    <span class="muControl">return</span>
+<span id="L71" class="LineNr">  71 </span>  <span class="Conceal">¦</span> delete-previous-character?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">8/backspace</span>
+<span id="L72" class="LineNr">  72 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> delete-previous-character?
+<span id="L73" class="LineNr">  73 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> <a href='003-shortcuts.mu.html#L73'>&lt;backspace-character-begin&gt;</a></span>
+<span id="L74" class="LineNr">  74 </span>  <span class="Conceal">¦</span> go-render?:bool, backspaced-cell:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L83'>delete-before-cursor</a> editor, <a href='../081print.mu.html#L4'>screen</a>
+<span id="L75" class="LineNr">  75 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> <a href='003-shortcuts.mu.html#L75'>&lt;backspace-character-end&gt;</a></span>
+<span id="L76" class="LineNr">  76 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
 <span id="L77" class="LineNr">  77 </span>  <span class="Delimiter">}</span>
 <span id="L78" class="LineNr">  78 </span>]
 <span id="L79" class="LineNr">  79 </span>
@@ -168,18 +169,18 @@ if ('onhashchange' in window) {
 <span id="L108" class="LineNr"> 108 </span>  <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, cursor-row, cursor-column
 <span id="L109" class="LineNr"> 109 </span>  curr-column:num <span class="Special">&lt;-</span> copy cursor-column
 <span id="L110" class="LineNr"> 110 </span>  <span class="Delimiter">{</span>
-<span id="L111" class="LineNr"> 111 </span>    <span class="Comment"># hit right margin? give up and let caller render</span>
-<span id="L112" class="LineNr"> 112 </span>    at-right?:bool <span class="Special">&lt;-</span> greater-or-equal curr-column, right
-<span id="L113" class="LineNr"> 113 </span>    <span class="muControl">return-if</span> at-right?, <span class="Constant">1/go-render</span>
-<span id="L114" class="LineNr"> 114 </span>    <span class="muControl">break-unless</span> curr
-<span id="L115" class="LineNr"> 115 </span>    <span class="Comment"># newline? done.</span>
-<span id="L116" class="LineNr"> 116 </span>    currc:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
-<span id="L117" class="LineNr"> 117 </span>    at-newline?:bool <span class="Special">&lt;-</span> equal currc, <span class="Constant">10/newline</span>
-<span id="L118" class="LineNr"> 118 </span>    <span class="muControl">break-if</span> at-newline?
-<span id="L119" class="LineNr"> 119 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> print <a href='../081print.mu.html#L4'>screen</a>, currc
-<span id="L120" class="LineNr"> 120 </span>    curr-column <span class="Special">&lt;-</span> add curr-column,<span class="Constant"> 1</span>
-<span id="L121" class="LineNr"> 121 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
-<span id="L122" class="LineNr"> 122 </span>    <span class="muControl">loop</span>
+<span id="L111" class="LineNr"> 111 </span>  <span class="Conceal">¦</span> <span class="Comment"># hit right margin? give up and let caller render</span>
+<span id="L112" class="LineNr"> 112 </span>  <span class="Conceal">¦</span> at-right?:bool <span class="Special">&lt;-</span> greater-or-equal curr-column, right
+<span id="L113" class="LineNr"> 113 </span>  <span class="Conceal">¦</span> <span class="muControl">return-if</span> at-right?, <span class="Constant">1/go-render</span>
+<span id="L114" class="LineNr"> 114 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> curr
+<span id="L115" class="LineNr"> 115 </span>  <span class="Conceal">¦</span> <span class="Comment"># newline? done.</span>
+<span id="L116" class="LineNr"> 116 </span>  <span class="Conceal">¦</span> currc:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
+<span id="L117" class="LineNr"> 117 </span>  <span class="Conceal">¦</span> at-newline?:bool <span class="Special">&lt;-</span> equal currc, <span class="Constant">10/newline</span>
+<span id="L118" class="LineNr"> 118 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-newline?
+<span id="L119" class="LineNr"> 119 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> print <a href='../081print.mu.html#L4'>screen</a>, currc
+<span id="L120" class="LineNr"> 120 </span>  <span class="Conceal">¦</span> curr-column <span class="Special">&lt;-</span> add curr-column,<span class="Constant"> 1</span>
+<span id="L121" class="LineNr"> 121 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L122" class="LineNr"> 122 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L123" class="LineNr"> 123 </span>  <span class="Delimiter">}</span>
 <span id="L124" class="LineNr"> 124 </span>  <span class="Comment"># we're guaranteed not to be at the right margin</span>
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@@ -197,49 +198,49 @@ if ('onhashchange' in window) {
 <span id="L137" class="LineNr"> 137 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
 <span id="L138" class="LineNr"> 138 </span>  <span class="Comment"># if not at left margin, move one character left</span>
 <span id="L139" class="LineNr"> 139 </span>  <span class="Delimiter">{</span>
-<span id="L140" class="LineNr"> 140 </span>    at-left-margin?:bool <span class="Special">&lt;-</span> equal cursor-column, left
-<span id="L141" class="LineNr"> 141 </span>    <span class="muControl">break-if</span> at-left-margin?
-<span id="L142" class="LineNr"> 142 </span>    trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[decrementing cursor column]</span>
-<span id="L143" class="LineNr"> 143 </span>    cursor-column <span class="Special">&lt;-</span> subtract cursor-column,<span class="Constant"> 1</span>
-<span id="L144" class="LineNr"> 144 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
-<span id="L145" class="LineNr"> 145 </span>    <span class="muControl">return</span>
+<span id="L140" class="LineNr"> 140 </span>  <span class="Conceal">¦</span> at-left-margin?:bool <span class="Special">&lt;-</span> equal cursor-column, left
+<span id="L141" class="LineNr"> 141 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-left-margin?
+<span id="L142" class="LineNr"> 142 </span>  <span class="Conceal">¦</span> trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[decrementing cursor column]</span>
+<span id="L143" class="LineNr"> 143 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> subtract cursor-column,<span class="Constant"> 1</span>
+<span id="L144" class="LineNr"> 144 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
+<span id="L145" class="LineNr"> 145 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
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 <span id="L147" class="LineNr"> 147 </span>  <span class="Comment"># if at left margin, we must move to previous row:</span>
 <span id="L148" class="LineNr"> 148 </span>  top-of-screen?:bool <span class="Special">&lt;-</span> equal cursor-row,<span class="Constant"> 1</span>  <span class="Comment"># exclude menu bar</span>
 <span id="L149" class="LineNr"> 149 </span>  <span class="Delimiter">{</span>
-<span id="L150" class="LineNr"> 150 </span>    <span class="muControl">break-if</span> top-of-screen?
-<span id="L151" class="LineNr"> 151 </span>    cursor-row <span class="Special">&lt;-</span> subtract cursor-row,<span class="Constant"> 1</span>
-<span id="L152" class="LineNr"> 152 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
+<span id="L150" class="LineNr"> 150 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> top-of-screen?
+<span id="L151" class="LineNr"> 151 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> subtract cursor-row,<span class="Constant"> 1</span>
+<span id="L152" class="LineNr"> 152 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
 <span id="L153" class="LineNr"> 153 </span>  <span class="Delimiter">}</span>
 <span id="L154" class="LineNr"> 154 </span>  <span class="Delimiter">{</span>
-<span id="L155" class="LineNr"> 155 </span>    <span class="muControl">break-unless</span> top-of-screen?
-<span id="L156" class="LineNr"> 156 </span><span class="Constant">    &lt;scroll-up&gt;</span>
-<span id="L157" class="LineNr"> 157 </span>    go-render? <span class="Special">&lt;-</span> copy <span class="Constant">1/true</span>
+<span id="L155" class="LineNr"> 155 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> top-of-screen?
+<span id="L156" class="LineNr"> 156 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;scroll-up&gt;</span>
+<span id="L157" class="LineNr"> 157 </span>  <span class="Conceal">¦</span> go-render? <span class="Special">&lt;-</span> copy <span class="Constant">1/true</span>
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 <span id="L159" class="LineNr"> 159 </span>  <span class="Delimiter">{</span>
-<span id="L160" class="LineNr"> 160 </span>    <span class="Comment"># case 1: if previous character was newline, figure out how long the previous line is</span>
-<span id="L161" class="LineNr"> 161 </span>    previous-character:char <span class="Special">&lt;-</span> get *before-cursor, <span class="Constant">value:offset</span>
-<span id="L162" class="LineNr"> 162 </span>    previous-character-is-newline?:bool <span class="Special">&lt;-</span> equal previous-character, <span class="Constant">10/newline</span>
-<span id="L163" class="LineNr"> 163 </span>    <span class="muControl">break-unless</span> previous-character-is-newline?
-<span id="L164" class="LineNr"> 164 </span>    <span class="Comment"># compute length of previous line</span>
-<span id="L165" class="LineNr"> 165 </span>    trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[switching to previous line]</span>
-<span id="L166" class="LineNr"> 166 </span>    d:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
-<span id="L167" class="LineNr"> 167 </span>    end-of-line:num <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L193'>previous-line-length</a> before-cursor, d
-<span id="L168" class="LineNr"> 168 </span>    right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
-<span id="L169" class="LineNr"> 169 </span>    width:num <span class="Special">&lt;-</span> subtract right, left
-<span id="L170" class="LineNr"> 170 </span>    wrap?:bool <span class="Special">&lt;-</span> greater-than end-of-line, width
-<span id="L171" class="LineNr"> 171 </span>    <span class="Delimiter">{</span>
-<span id="L172" class="LineNr"> 172 </span>      <span class="muControl">break-unless</span> wrap?
-<span id="L173" class="LineNr"> 173 </span>      _, column-offset:num <span class="Special">&lt;-</span> divide-with-remainder end-of-line, width
-<span id="L174" class="LineNr"> 174 </span>      cursor-column <span class="Special">&lt;-</span> add left, column-offset
-<span id="L175" class="LineNr"> 175 </span>      *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
-<span id="L176" class="LineNr"> 176 </span>    <span class="Delimiter">}</span>
-<span id="L177" class="LineNr"> 177 </span>    <span class="Delimiter">{</span>
-<span id="L178" class="LineNr"> 178 </span>      <span class="muControl">break-if</span> wrap?
-<span id="L179" class="LineNr"> 179 </span>      cursor-column <span class="Special">&lt;-</span> add left, end-of-line
-<span id="L180" class="LineNr"> 180 </span>      *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
-<span id="L181" class="LineNr"> 181 </span>    <span class="Delimiter">}</span>
-<span id="L182" class="LineNr"> 182 </span>    <span class="muControl">return</span>
+<span id="L160" class="LineNr"> 160 </span>  <span class="Conceal">¦</span> <span class="Comment"># case 1: if previous character was newline, figure out how long the previous line is</span>
+<span id="L161" class="LineNr"> 161 </span>  <span class="Conceal">¦</span> previous-character:char <span class="Special">&lt;-</span> get *before-cursor, <span class="Constant">value:offset</span>
+<span id="L162" class="LineNr"> 162 </span>  <span class="Conceal">¦</span> previous-character-is-newline?:bool <span class="Special">&lt;-</span> equal previous-character, <span class="Constant">10/newline</span>
+<span id="L163" class="LineNr"> 163 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> previous-character-is-newline?
+<span id="L164" class="LineNr"> 164 </span>  <span class="Conceal">¦</span> <span class="Comment"># compute length of previous line</span>
+<span id="L165" class="LineNr"> 165 </span>  <span class="Conceal">¦</span> trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[switching to previous line]</span>
+<span id="L166" class="LineNr"> 166 </span>  <span class="Conceal">¦</span> d:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
+<span id="L167" class="LineNr"> 167 </span>  <span class="Conceal">¦</span> end-of-line:num <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L193'>previous-line-length</a> before-cursor, d
+<span id="L168" class="LineNr"> 168 </span>  <span class="Conceal">¦</span> right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
+<span id="L169" class="LineNr"> 169 </span>  <span class="Conceal">¦</span> width:num <span class="Special">&lt;-</span> subtract right, left
+<span id="L170" class="LineNr"> 170 </span>  <span class="Conceal">¦</span> wrap?:bool <span class="Special">&lt;-</span> greater-than end-of-line, width
+<span id="L171" class="LineNr"> 171 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L172" class="LineNr"> 172 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> wrap?
+<span id="L173" class="LineNr"> 173 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> _, column-offset:num <span class="Special">&lt;-</span> divide-with-remainder end-of-line, width
+<span id="L174" class="LineNr"> 174 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> add left, column-offset
+<span id="L175" class="LineNr"> 175 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
+<span id="L176" class="LineNr"> 176 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L177" class="LineNr"> 177 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L178" class="LineNr"> 178 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> wrap?
+<span id="L179" class="LineNr"> 179 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> add left, end-of-line
+<span id="L180" class="LineNr"> 180 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
+<span id="L181" class="LineNr"> 181 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L182" class="LineNr"> 182 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
 <span id="L183" class="LineNr"> 183 </span>  <span class="Delimiter">}</span>
 <span id="L184" class="LineNr"> 184 </span>  <span class="Comment"># case 2: if previous-character was not newline, we're just at a wrapped line</span>
 <span id="L185" class="LineNr"> 185 </span>  trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[wrapping to previous line]</span>
@@ -258,15 +259,15 @@ if ('onhashchange' in window) {
 <span id="L198" class="LineNr"> 198 </span>  at-start?:bool <span class="Special">&lt;-</span> equal curr, start
 <span id="L199" class="LineNr"> 199 </span>  <span class="muControl">return-if</span> at-start?
 <span id="L200" class="LineNr"> 200 </span>  <span class="Delimiter">{</span>
-<span id="L201" class="LineNr"> 201 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> curr
-<span id="L202" class="LineNr"> 202 </span>    <span class="muControl">break-unless</span> curr
-<span id="L203" class="LineNr"> 203 </span>    at-start?:bool <span class="Special">&lt;-</span> equal curr, start
-<span id="L204" class="LineNr"> 204 </span>    <span class="muControl">break-if</span> at-start?
-<span id="L205" class="LineNr"> 205 </span>    c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
-<span id="L206" class="LineNr"> 206 </span>    at-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
-<span id="L207" class="LineNr"> 207 </span>    <span class="muControl">break-if</span> at-newline?
-<span id="L208" class="LineNr"> 208 </span>    result <span class="Special">&lt;-</span> add result,<span class="Constant"> 1</span>
-<span id="L209" class="LineNr"> 209 </span>    <span class="muControl">loop</span>
+<span id="L201" class="LineNr"> 201 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> curr
+<span id="L202" class="LineNr"> 202 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> curr
+<span id="L203" class="LineNr"> 203 </span>  <span class="Conceal">¦</span> at-start?:bool <span class="Special">&lt;-</span> equal curr, start
+<span id="L204" class="LineNr"> 204 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-start?
+<span id="L205" class="LineNr"> 205 </span>  <span class="Conceal">¦</span> c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
+<span id="L206" class="LineNr"> 206 </span>  <span class="Conceal">¦</span> at-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
+<span id="L207" class="LineNr"> 207 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-newline?
+<span id="L208" class="LineNr"> 208 </span>  <span class="Conceal">¦</span> result <span class="Special">&lt;-</span> add result,<span class="Constant"> 1</span>
+<span id="L209" class="LineNr"> 209 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L210" class="LineNr"> 210 </span>  <span class="Delimiter">}</span>
 <span id="L211" class="LineNr"> 211 </span>]
 <span id="L212" class="LineNr"> 212 </span>
@@ -278,23 +279,23 @@ if ('onhashchange' in window) {
 <span id="L218" class="LineNr"> 218 </span><span class="Constant">cd]</span>
 <span id="L219" class="LineNr"> 219 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L220" class="LineNr"> 220 </span>  assume-console [
-<span id="L221" class="LineNr"> 221 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>  <span class="Comment"># cursor at only character in final line</span>
-<span id="L222" class="LineNr"> 222 </span>    press backspace
+<span id="L221" class="LineNr"> 221 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>  <span class="Comment"># cursor at only character in final line</span>
+<span id="L222" class="LineNr"> 222 </span>  <span class="Conceal">¦</span> press backspace
 <span id="L223" class="LineNr"> 223 </span>  ]
 <span id="L224" class="LineNr"> 224 </span>  run [
-<span id="L225" class="LineNr"> 225 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L226" class="LineNr"> 226 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L227" class="LineNr"> 227 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L225" class="LineNr"> 225 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L226" class="LineNr"> 226 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L227" class="LineNr"> 227 </span>  <span class="Conceal">¦</span> 5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L228" class="LineNr"> 228 </span>  ]
 <span id="L229" class="LineNr"> 229 </span>  screen-should-contain [
-<span id="L230" class="LineNr"> 230 </span>   <span class="Constant"> .          .</span>
-<span id="L231" class="LineNr"> 231 </span>   <span class="Constant"> .abcd      .</span>
-<span id="L232" class="LineNr"> 232 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L233" class="LineNr"> 233 </span>   <span class="Constant"> .          .</span>
+<span id="L230" class="LineNr"> 230 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L231" class="LineNr"> 231 </span>  <span class="Conceal">¦</span><span class="Constant"> .abcd      .</span>
+<span id="L232" class="LineNr"> 232 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L233" class="LineNr"> 233 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L234" class="LineNr"> 234 </span>  ]
 <span id="L235" class="LineNr"> 235 </span>  memory-should-contain [
-<span id="L236" class="LineNr"> 236 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L237" class="LineNr"> 237 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L236" class="LineNr"> 236 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L237" class="LineNr"> 237 </span>  <span class="Conceal">¦</span><span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
 <span id="L238" class="LineNr"> 238 </span>  ]
 <span id="L239" class="LineNr"> 239 </span>]
 <span id="L240" class="LineNr"> 240 </span>
@@ -309,19 +310,19 @@ if ('onhashchange' in window) {
 <span id="L249" class="LineNr"> 249 </span>  $clear-trace
 <span id="L250" class="LineNr"> 250 </span>  <span class="Comment"># position the cursor at the start of the second and hit backspace</span>
 <span id="L251" class="LineNr"> 251 </span>  assume-console [
-<span id="L252" class="LineNr"> 252 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
-<span id="L253" class="LineNr"> 253 </span>    press backspace
+<span id="L252" class="LineNr"> 252 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
+<span id="L253" class="LineNr"> 253 </span>  <span class="Conceal">¦</span> press backspace
 <span id="L254" class="LineNr"> 254 </span>  ]
 <span id="L255" class="LineNr"> 255 </span>  run [
-<span id="L256" class="LineNr"> 256 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L256" class="LineNr"> 256 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L257" class="LineNr"> 257 </span>  ]
 <span id="L258" class="LineNr"> 258 </span>  <span class="Comment"># resulting single line should wrap correctly</span>
 <span id="L259" class="LineNr"> 259 </span>  screen-should-contain [
-<span id="L260" class="LineNr"> 260 </span>   <span class="Constant"> .          .</span>
-<span id="L261" class="LineNr"> 261 </span>   <span class="Constant"> .abc defgh↩.</span>
-<span id="L262" class="LineNr"> 262 </span>   <span class="Constant"> .i jkl     .</span>
-<span id="L263" class="LineNr"> 263 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L264" class="LineNr"> 264 </span>   <span class="Constant"> .          .</span>
+<span id="L260" class="LineNr"> 260 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L261" class="LineNr"> 261 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc defgh↩.</span>
+<span id="L262" class="LineNr"> 262 </span>  <span class="Conceal">¦</span><span class="Constant"> .i jkl     .</span>
+<span id="L263" class="LineNr"> 263 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L264" class="LineNr"> 264 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L265" class="LineNr"> 265 </span>  ]
 <span id="L266" class="LineNr"> 266 </span>]
 <span id="L267" class="LineNr"> 267 </span>
@@ -333,27 +334,27 @@ if ('onhashchange' in window) {
 <span id="L273" class="LineNr"> 273 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L274" class="LineNr"> 274 </span>  <span class="Comment"># confirm that it wraps</span>
 <span id="L275" class="LineNr"> 275 </span>  screen-should-contain [
-<span id="L276" class="LineNr"> 276 </span>   <span class="Constant"> .          .</span>
-<span id="L277" class="LineNr"> 277 </span>   <span class="Constant"> .abc def↩  .</span>
-<span id="L278" class="LineNr"> 278 </span>   <span class="Constant"> . ghij     .</span>
-<span id="L279" class="LineNr"> 279 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌  .</span>
+<span id="L276" class="LineNr"> 276 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L277" class="LineNr"> 277 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc def↩  .</span>
+<span id="L278" class="LineNr"> 278 </span>  <span class="Conceal">¦</span><span class="Constant"> . ghij     .</span>
+<span id="L279" class="LineNr"> 279 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌  .</span>
 <span id="L280" class="LineNr"> 280 </span>  ]
 <span id="L281" class="LineNr"> 281 </span>  $clear-trace
 <span id="L282" class="LineNr"> 282 </span>  <span class="Comment"># position the cursor somewhere in the middle of the top screen line and hit backspace</span>
 <span id="L283" class="LineNr"> 283 </span>  assume-console [
-<span id="L284" class="LineNr"> 284 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 4</span>
-<span id="L285" class="LineNr"> 285 </span>    press backspace
+<span id="L284" class="LineNr"> 284 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 4</span>
+<span id="L285" class="LineNr"> 285 </span>  <span class="Conceal">¦</span> press backspace
 <span id="L286" class="LineNr"> 286 </span>  ]
 <span id="L287" class="LineNr"> 287 </span>  run [
-<span id="L288" class="LineNr"> 288 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L288" class="LineNr"> 288 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L289" class="LineNr"> 289 </span>  ]
 <span id="L290" class="LineNr"> 290 </span>  <span class="Comment"># resulting single line should wrap correctly and not overflow its bounds</span>
 <span id="L291" class="LineNr"> 291 </span>  screen-should-contain [
-<span id="L292" class="LineNr"> 292 </span>   <span class="Constant"> .          .</span>
-<span id="L293" class="LineNr"> 293 </span>   <span class="Constant"> .abcdef ↩  .</span>
-<span id="L294" class="LineNr"> 294 </span>   <span class="Constant"> .ghij      .</span>
-<span id="L295" class="LineNr"> 295 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌  .</span>
-<span id="L296" class="LineNr"> 296 </span>   <span class="Constant"> .          .</span>
+<span id="L292" class="LineNr"> 292 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L293" class="LineNr"> 293 </span>  <span class="Conceal">¦</span><span class="Constant"> .abcdef ↩  .</span>
+<span id="L294" class="LineNr"> 294 </span>  <span class="Conceal">¦</span><span class="Constant"> .ghij      .</span>
+<span id="L295" class="LineNr"> 295 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌  .</span>
+<span id="L296" class="LineNr"> 296 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L297" class="LineNr"> 297 </span>  ]
 <span id="L298" class="LineNr"> 298 </span>]
 <span id="L299" class="LineNr"> 299 </span>
@@ -366,42 +367,42 @@ if ('onhashchange' in window) {
 <span id="L306" class="LineNr"> 306 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L307" class="LineNr"> 307 </span>  $clear-trace
 <span id="L308" class="LineNr"> 308 </span>  assume-console [
-<span id="L309" class="LineNr"> 309 </span>    press delete
+<span id="L309" class="LineNr"> 309 </span>  <span class="Conceal">¦</span> press delete
 <span id="L310" class="LineNr"> 310 </span>  ]
 <span id="L311" class="LineNr"> 311 </span>  run [
-<span id="L312" class="LineNr"> 312 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L312" class="LineNr"> 312 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L313" class="LineNr"> 313 </span>  ]
 <span id="L314" class="LineNr"> 314 </span>  screen-should-contain [
-<span id="L315" class="LineNr"> 315 </span>   <span class="Constant"> .          .</span>
-<span id="L316" class="LineNr"> 316 </span>   <span class="Constant"> .bc        .</span>
-<span id="L317" class="LineNr"> 317 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L318" class="LineNr"> 318 </span>   <span class="Constant"> .          .</span>
+<span id="L315" class="LineNr"> 315 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L316" class="LineNr"> 316 </span>  <span class="Conceal">¦</span><span class="Constant"> .bc        .</span>
+<span id="L317" class="LineNr"> 317 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L318" class="LineNr"> 318 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L319" class="LineNr"> 319 </span>  ]
 <span id="L320" class="LineNr"> 320 </span>  check-trace-count-for-label<span class="Constant"> 3</span>, <span class="Constant">[print-character]</span>  <span class="Comment"># length of original line to overwrite</span>
 <span id="L321" class="LineNr"> 321 </span>  $clear-trace
 <span id="L322" class="LineNr"> 322 </span>  assume-console [
-<span id="L323" class="LineNr"> 323 </span>    press delete
+<span id="L323" class="LineNr"> 323 </span>  <span class="Conceal">¦</span> press delete
 <span id="L324" class="LineNr"> 324 </span>  ]
 <span id="L325" class="LineNr"> 325 </span>  run [
-<span id="L326" class="LineNr"> 326 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L326" class="LineNr"> 326 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L327" class="LineNr"> 327 </span>  ]
 <span id="L328" class="LineNr"> 328 </span>  screen-should-contain [
-<span id="L329" class="LineNr"> 329 </span>   <span class="Constant"> .          .</span>
-<span id="L330" class="LineNr"> 330 </span>   <span class="Constant"> .c         .</span>
-<span id="L331" class="LineNr"> 331 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L332" class="LineNr"> 332 </span>   <span class="Constant"> .          .</span>
+<span id="L329" class="LineNr"> 329 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L330" class="LineNr"> 330 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
+<span id="L331" class="LineNr"> 331 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L332" class="LineNr"> 332 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L333" class="LineNr"> 333 </span>  ]
 <span id="L334" class="LineNr"> 334 </span>  check-trace-count-for-label<span class="Constant"> 2</span>, <span class="Constant">[print-character]</span>  <span class="Comment"># new length to overwrite</span>
 <span id="L335" class="LineNr"> 335 </span>]
 <span id="L336" class="LineNr"> 336 </span>
 <span id="L337" class="LineNr"> 337 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L197'>&lt;handle-special-key&gt;</a></span> [
 <span id="L338" class="LineNr"> 338 </span>  <span class="Delimiter">{</span>
-<span id="L339" class="LineNr"> 339 </span>    delete-next-character?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65522/delete</span>
-<span id="L340" class="LineNr"> 340 </span>    <span class="muControl">break-unless</span> delete-next-character?
-<span id="L341" class="LineNr"> 341 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L341'>&lt;delete-character-begin&gt;</a></span>
-<span id="L342" class="LineNr"> 342 </span>    go-render?:bool, deleted-cell:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L348'>delete-at-cursor</a> editor, <a href='../081print.mu.html#L4'>screen</a>
-<span id="L343" class="LineNr"> 343 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L343'>&lt;delete-character-end&gt;</a></span>
-<span id="L344" class="LineNr"> 344 </span>    <span class="muControl">return</span>
+<span id="L339" class="LineNr"> 339 </span>  <span class="Conceal">¦</span> delete-next-character?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65522/delete</span>
+<span id="L340" class="LineNr"> 340 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> delete-next-character?
+<span id="L341" class="LineNr"> 341 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> <a href='003-shortcuts.mu.html#L341'>&lt;delete-character-begin&gt;</a></span>
+<span id="L342" class="LineNr"> 342 </span>  <span class="Conceal">¦</span> go-render?:bool, deleted-cell:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L348'>delete-at-cursor</a> editor, <a href='../081print.mu.html#L4'>screen</a>
+<span id="L343" class="LineNr"> 343 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> <a href='003-shortcuts.mu.html#L343'>&lt;delete-character-end&gt;</a></span>
+<span id="L344" class="LineNr"> 344 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
 <span id="L345" class="LineNr"> 345 </span>  <span class="Delimiter">}</span>
 <span id="L346" class="LineNr"> 346 </span>]
 <span id="L347" class="LineNr"> 347 </span>
@@ -424,18 +425,18 @@ if ('onhashchange' in window) {
 <span id="L364" class="LineNr"> 364 </span>  curr-column:num <span class="Special">&lt;-</span> copy cursor-column
 <span id="L365" class="LineNr"> 365 </span>  <a href='../081print.mu.html#L581'>screen-width</a>:num <span class="Special">&lt;-</span> <a href='../081print.mu.html#L581'>screen-width</a> <a href='../081print.mu.html#L4'>screen</a>
 <span id="L366" class="LineNr"> 366 </span>  <span class="Delimiter">{</span>
-<span id="L367" class="LineNr"> 367 </span>    <span class="Comment"># hit right margin? give up and let caller render</span>
-<span id="L368" class="LineNr"> 368 </span>    at-right?:bool <span class="Special">&lt;-</span> greater-or-equal curr-column, <a href='../081print.mu.html#L581'>screen-width</a>
-<span id="L369" class="LineNr"> 369 </span>    <span class="muControl">return-if</span> at-right?, <span class="Constant">1/go-render</span>
-<span id="L370" class="LineNr"> 370 </span>    <span class="muControl">break-unless</span> curr
-<span id="L371" class="LineNr"> 371 </span>    <span class="Comment"># newline? done.</span>
-<span id="L372" class="LineNr"> 372 </span>    currc:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
-<span id="L373" class="LineNr"> 373 </span>    at-newline?:bool <span class="Special">&lt;-</span> equal currc, <span class="Constant">10/newline</span>
-<span id="L374" class="LineNr"> 374 </span>    <span class="muControl">break-if</span> at-newline?
-<span id="L375" class="LineNr"> 375 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> print <a href='../081print.mu.html#L4'>screen</a>, currc
-<span id="L376" class="LineNr"> 376 </span>    curr-column <span class="Special">&lt;-</span> add curr-column,<span class="Constant"> 1</span>
-<span id="L377" class="LineNr"> 377 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
-<span id="L378" class="LineNr"> 378 </span>    <span class="muControl">loop</span>
+<span id="L367" class="LineNr"> 367 </span>  <span class="Conceal">¦</span> <span class="Comment"># hit right margin? give up and let caller render</span>
+<span id="L368" class="LineNr"> 368 </span>  <span class="Conceal">¦</span> at-right?:bool <span class="Special">&lt;-</span> greater-or-equal curr-column, <a href='../081print.mu.html#L581'>screen-width</a>
+<span id="L369" class="LineNr"> 369 </span>  <span class="Conceal">¦</span> <span class="muControl">return-if</span> at-right?, <span class="Constant">1/go-render</span>
+<span id="L370" class="LineNr"> 370 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> curr
+<span id="L371" class="LineNr"> 371 </span>  <span class="Conceal">¦</span> <span class="Comment"># newline? done.</span>
+<span id="L372" class="LineNr"> 372 </span>  <span class="Conceal">¦</span> currc:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
+<span id="L373" class="LineNr"> 373 </span>  <span class="Conceal">¦</span> at-newline?:bool <span class="Special">&lt;-</span> equal currc, <span class="Constant">10/newline</span>
+<span id="L374" class="LineNr"> 374 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-newline?
+<span id="L375" class="LineNr"> 375 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> print <a href='../081print.mu.html#L4'>screen</a>, currc
+<span id="L376" class="LineNr"> 376 </span>  <span class="Conceal">¦</span> curr-column <span class="Special">&lt;-</span> add curr-column,<span class="Constant"> 1</span>
+<span id="L377" class="LineNr"> 377 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L378" class="LineNr"> 378 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L379" class="LineNr"> 379 </span>  <span class="Delimiter">}</span>
 <span id="L380" class="LineNr"> 380 </span>  <span class="Comment"># we're guaranteed not to be at the right margin</span>
 <span id="L381" class="LineNr"> 381 </span>  space:char <span class="Special">&lt;-</span> copy <span class="Constant">32/space</span>
@@ -452,37 +453,37 @@ if ('onhashchange' in window) {
 <span id="L392" class="LineNr"> 392 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L393" class="LineNr"> 393 </span>  $clear-trace
 <span id="L394" class="LineNr"> 394 </span>  assume-console [
-<span id="L395" class="LineNr"> 395 </span>    press right-arrow
-<span id="L396" class="LineNr"> 396 </span>    type <span class="Constant">[0]</span>
+<span id="L395" class="LineNr"> 395 </span>  <span class="Conceal">¦</span> press right-arrow
+<span id="L396" class="LineNr"> 396 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
 <span id="L397" class="LineNr"> 397 </span>  ]
 <span id="L398" class="LineNr"> 398 </span>  run [
-<span id="L399" class="LineNr"> 399 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L399" class="LineNr"> 399 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L400" class="LineNr"> 400 </span>  ]
 <span id="L401" class="LineNr"> 401 </span>  screen-should-contain [
-<span id="L402" class="LineNr"> 402 </span>   <span class="Constant"> .          .</span>
-<span id="L403" class="LineNr"> 403 </span>   <span class="Constant"> .a0bc      .</span>
-<span id="L404" class="LineNr"> 404 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L405" class="LineNr"> 405 </span>   <span class="Constant"> .          .</span>
+<span id="L402" class="LineNr"> 402 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L403" class="LineNr"> 403 </span>  <span class="Conceal">¦</span><span class="Constant"> .a0bc      .</span>
+<span id="L404" class="LineNr"> 404 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L405" class="LineNr"> 405 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L406" class="LineNr"> 406 </span>  ]
 <span id="L407" class="LineNr"> 407 </span>  check-trace-count-for-label<span class="Constant"> 3</span>, <span class="Constant">[print-character]</span>  <span class="Comment"># 0 and following characters</span>
 <span id="L408" class="LineNr"> 408 </span>]
 <span id="L409" class="LineNr"> 409 </span>
 <span id="L410" class="LineNr"> 410 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L197'>&lt;handle-special-key&gt;</a></span> [
 <span id="L411" class="LineNr"> 411 </span>  <span class="Delimiter">{</span>
-<span id="L412" class="LineNr"> 412 </span>    move-to-next-character?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65514/right-arrow</span>
-<span id="L413" class="LineNr"> 413 </span>    <span class="muControl">break-unless</span> move-to-next-character?
-<span id="L414" class="LineNr"> 414 </span>    <span class="Comment"># if not at end of text</span>
-<span id="L415" class="LineNr"> 415 </span>    next-cursor:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
-<span id="L416" class="LineNr"> 416 </span>    <span class="muControl">break-unless</span> next-cursor
-<span id="L417" class="LineNr"> 417 </span>    <span class="Comment"># scan to next character</span>
-<span id="L418" class="LineNr"> 418 </span><span class="Constant">    &lt;move-cursor-begin&gt;</span>
-<span id="L419" class="LineNr"> 419 </span>    before-cursor <span class="Special">&lt;-</span> copy next-cursor
-<span id="L420" class="LineNr"> 420 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
-<span id="L421" class="LineNr"> 421 </span>    go-render?:bool <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L429'>move-cursor-coordinates-right</a> editor, <a href='../081print.mu.html#L594'>screen-height</a>
-<span id="L422" class="LineNr"> 422 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, cursor-row, cursor-column
-<span id="L423" class="LineNr"> 423 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">2/right-arrow</span>
-<span id="L424" class="LineNr"> 424 </span><span class="Constant">    &lt;move-cursor-end&gt;</span>
-<span id="L425" class="LineNr"> 425 </span>    <span class="muControl">return</span>
+<span id="L412" class="LineNr"> 412 </span>  <span class="Conceal">¦</span> move-to-next-character?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65514/right-arrow</span>
+<span id="L413" class="LineNr"> 413 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> move-to-next-character?
+<span id="L414" class="LineNr"> 414 </span>  <span class="Conceal">¦</span> <span class="Comment"># if not at end of text</span>
+<span id="L415" class="LineNr"> 415 </span>  <span class="Conceal">¦</span> next-cursor:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L416" class="LineNr"> 416 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> next-cursor
+<span id="L417" class="LineNr"> 417 </span>  <span class="Conceal">¦</span> <span class="Comment"># scan to next character</span>
+<span id="L418" class="LineNr"> 418 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-begin&gt;</span>
+<span id="L419" class="LineNr"> 419 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy next-cursor
+<span id="L420" class="LineNr"> 420 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
+<span id="L421" class="LineNr"> 421 </span>  <span class="Conceal">¦</span> go-render?:bool <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L429'>move-cursor-coordinates-right</a> editor, <a href='../081print.mu.html#L594'>screen-height</a>
+<span id="L422" class="LineNr"> 422 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, cursor-row, cursor-column
+<span id="L423" class="LineNr"> 423 </span>  <span class="Conceal">¦</span> undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">2/right-arrow</span>
+<span id="L424" class="LineNr"> 424 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-end&gt;</span>
+<span id="L425" class="LineNr"> 425 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
 <span id="L426" class="LineNr"> 426 </span>  <span class="Delimiter">}</span>
 <span id="L427" class="LineNr"> 427 </span>]
 <span id="L428" class="LineNr"> 428 </span>
@@ -496,42 +497,42 @@ if ('onhashchange' in window) {
 <span id="L436" class="LineNr"> 436 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
 <span id="L437" class="LineNr"> 437 </span>  <span class="Comment"># if crossed a newline, move cursor to start of next row</span>
 <span id="L438" class="LineNr"> 438 </span>  <span class="Delimiter">{</span>
-<span id="L439" class="LineNr"> 439 </span>    old-cursor-character:char <span class="Special">&lt;-</span> get *before-cursor, <span class="Constant">value:offset</span>
-<span id="L440" class="LineNr"> 440 </span>    was-at-newline?:bool <span class="Special">&lt;-</span> equal old-cursor-character, <span class="Constant">10/newline</span>
-<span id="L441" class="LineNr"> 441 </span>    <span class="muControl">break-unless</span> was-at-newline?
-<span id="L442" class="LineNr"> 442 </span>    cursor-row <span class="Special">&lt;-</span> add cursor-row,<span class="Constant"> 1</span>
-<span id="L443" class="LineNr"> 443 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
-<span id="L444" class="LineNr"> 444 </span>    cursor-column <span class="Special">&lt;-</span> copy left
-<span id="L445" class="LineNr"> 445 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
-<span id="L446" class="LineNr"> 446 </span>    below-screen?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-row, <a href='../081print.mu.html#L594'>screen-height</a>  <span class="Comment"># must be equal</span>
-<span id="L447" class="LineNr"> 447 </span>    <span class="muControl">return-unless</span> below-screen?, <span class="Constant">0/don't-render</span>
-<span id="L448" class="LineNr"> 448 </span><span class="Constant">    &lt;scroll-down&gt;</span>
-<span id="L449" class="LineNr"> 449 </span>    cursor-row <span class="Special">&lt;-</span> subtract cursor-row,<span class="Constant"> 1</span>  <span class="Comment"># bring back into screen range</span>
-<span id="L450" class="LineNr"> 450 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
-<span id="L451" class="LineNr"> 451 </span>    <span class="muControl">return</span> <span class="Constant">1/go-render</span>
+<span id="L439" class="LineNr"> 439 </span>  <span class="Conceal">¦</span> old-cursor-character:char <span class="Special">&lt;-</span> get *before-cursor, <span class="Constant">value:offset</span>
+<span id="L440" class="LineNr"> 440 </span>  <span class="Conceal">¦</span> was-at-newline?:bool <span class="Special">&lt;-</span> equal old-cursor-character, <span class="Constant">10/newline</span>
+<span id="L441" class="LineNr"> 441 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> was-at-newline?
+<span id="L442" class="LineNr"> 442 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> add cursor-row,<span class="Constant"> 1</span>
+<span id="L443" class="LineNr"> 443 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
+<span id="L444" class="LineNr"> 444 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> copy left
+<span id="L445" class="LineNr"> 445 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
+<span id="L446" class="LineNr"> 446 </span>  <span class="Conceal">¦</span> below-screen?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-row, <a href='../081print.mu.html#L594'>screen-height</a>  <span class="Comment"># must be equal</span>
+<span id="L447" class="LineNr"> 447 </span>  <span class="Conceal">¦</span> <span class="muControl">return-unless</span> below-screen?, <span class="Constant">0/don't-render</span>
+<span id="L448" class="LineNr"> 448 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;scroll-down&gt;</span>
+<span id="L449" class="LineNr"> 449 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> subtract cursor-row,<span class="Constant"> 1</span>  <span class="Comment"># bring back into screen range</span>
+<span id="L450" class="LineNr"> 450 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
+<span id="L451" class="LineNr"> 451 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">1/go-render</span>
 <span id="L452" class="LineNr"> 452 </span>  <span class="Delimiter">}</span>
 <span id="L453" class="LineNr"> 453 </span>  <span class="Comment"># if the line wraps, move cursor to start of next row</span>
 <span id="L454" class="LineNr"> 454 </span>  <span class="Delimiter">{</span>
-<span id="L455" class="LineNr"> 455 </span>    <span class="Comment"># if we're at the column just before the wrap indicator</span>
-<span id="L456" class="LineNr"> 456 </span>    wrap-column:num <span class="Special">&lt;-</span> subtract right,<span class="Constant"> 1</span>
-<span id="L457" class="LineNr"> 457 </span>    at-wrap?:bool <span class="Special">&lt;-</span> equal cursor-column, wrap-column
-<span id="L458" class="LineNr"> 458 </span>    <span class="muControl">break-unless</span> at-wrap?
-<span id="L459" class="LineNr"> 459 </span>    <span class="Comment"># and if next character isn't newline</span>
-<span id="L460" class="LineNr"> 460 </span>    <a href='../065duplex_list.mu.html#L29'>next</a>:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
-<span id="L461" class="LineNr"> 461 </span>    <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L29'>next</a>
-<span id="L462" class="LineNr"> 462 </span>    next-character:char <span class="Special">&lt;-</span> get *next, <span class="Constant">value:offset</span>
-<span id="L463" class="LineNr"> 463 </span>    newline?:bool <span class="Special">&lt;-</span> equal next-character, <span class="Constant">10/newline</span>
-<span id="L464" class="LineNr"> 464 </span>    <span class="muControl">break-if</span> newline?
-<span id="L465" class="LineNr"> 465 </span>    cursor-row <span class="Special">&lt;-</span> add cursor-row,<span class="Constant"> 1</span>
-<span id="L466" class="LineNr"> 466 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
-<span id="L467" class="LineNr"> 467 </span>    cursor-column <span class="Special">&lt;-</span> copy left
-<span id="L468" class="LineNr"> 468 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
-<span id="L469" class="LineNr"> 469 </span>    below-screen?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-row, <a href='../081print.mu.html#L594'>screen-height</a>  <span class="Comment"># must be equal</span>
-<span id="L470" class="LineNr"> 470 </span>    <span class="muControl">return-unless</span> below-screen?, <span class="Constant">0/no-more-render</span>
-<span id="L471" class="LineNr"> 471 </span><span class="Constant">    &lt;scroll-down&gt;</span>
-<span id="L472" class="LineNr"> 472 </span>    cursor-row <span class="Special">&lt;-</span> subtract cursor-row,<span class="Constant"> 1</span>  <span class="Comment"># bring back into screen range</span>
-<span id="L473" class="LineNr"> 473 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
-<span id="L474" class="LineNr"> 474 </span>    <span class="muControl">return</span> <span class="Constant">1/go-render</span>
+<span id="L455" class="LineNr"> 455 </span>  <span class="Conceal">¦</span> <span class="Comment"># if we're at the column just before the wrap indicator</span>
+<span id="L456" class="LineNr"> 456 </span>  <span class="Conceal">¦</span> wrap-column:num <span class="Special">&lt;-</span> subtract right,<span class="Constant"> 1</span>
+<span id="L457" class="LineNr"> 457 </span>  <span class="Conceal">¦</span> at-wrap?:bool <span class="Special">&lt;-</span> equal cursor-column, wrap-column
+<span id="L458" class="LineNr"> 458 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-wrap?
+<span id="L459" class="LineNr"> 459 </span>  <span class="Conceal">¦</span> <span class="Comment"># and if next character isn't newline</span>
+<span id="L460" class="LineNr"> 460 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L29'>next</a>:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L461" class="LineNr"> 461 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L29'>next</a>
+<span id="L462" class="LineNr"> 462 </span>  <span class="Conceal">¦</span> next-character:char <span class="Special">&lt;-</span> get *next, <span class="Constant">value:offset</span>
+<span id="L463" class="LineNr"> 463 </span>  <span class="Conceal">¦</span> newline?:bool <span class="Special">&lt;-</span> equal next-character, <span class="Constant">10/newline</span>
+<span id="L464" class="LineNr"> 464 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> newline?
+<span id="L465" class="LineNr"> 465 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> add cursor-row,<span class="Constant"> 1</span>
+<span id="L466" class="LineNr"> 466 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
+<span id="L467" class="LineNr"> 467 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> copy left
+<span id="L468" class="LineNr"> 468 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
+<span id="L469" class="LineNr"> 469 </span>  <span class="Conceal">¦</span> below-screen?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-row, <a href='../081print.mu.html#L594'>screen-height</a>  <span class="Comment"># must be equal</span>
+<span id="L470" class="LineNr"> 470 </span>  <span class="Conceal">¦</span> <span class="muControl">return-unless</span> below-screen?, <span class="Constant">0/no-more-render</span>
+<span id="L471" class="LineNr"> 471 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;scroll-down&gt;</span>
+<span id="L472" class="LineNr"> 472 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> subtract cursor-row,<span class="Constant"> 1</span>  <span class="Comment"># bring back into screen range</span>
+<span id="L473" class="LineNr"> 473 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
+<span id="L474" class="LineNr"> 474 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">1/go-render</span>
 <span id="L475" class="LineNr"> 475 </span>  <span class="Delimiter">}</span>
 <span id="L476" class="LineNr"> 476 </span>  <span class="Comment"># otherwise move cursor one character right</span>
 <span id="L477" class="LineNr"> 477 </span>  cursor-column <span class="Special">&lt;-</span> add cursor-column,<span class="Constant"> 1</span>
@@ -549,28 +550,28 @@ if ('onhashchange' in window) {
 <span id="L489" class="LineNr"> 489 </span>  $clear-trace
 <span id="L490" class="LineNr"> 490 </span>  <span class="Comment"># type right-arrow a few times to get to start of second line</span>
 <span id="L491" class="LineNr"> 491 </span>  assume-console [
-<span id="L492" class="LineNr"> 492 </span>    press right-arrow
-<span id="L493" class="LineNr"> 493 </span>    press right-arrow
-<span id="L494" class="LineNr"> 494 </span>    press right-arrow
-<span id="L495" class="LineNr"> 495 </span>    press right-arrow  <span class="Comment"># next line</span>
+<span id="L492" class="LineNr"> 492 </span>  <span class="Conceal">¦</span> press right-arrow
+<span id="L493" class="LineNr"> 493 </span>  <span class="Conceal">¦</span> press right-arrow
+<span id="L494" class="LineNr"> 494 </span>  <span class="Conceal">¦</span> press right-arrow
+<span id="L495" class="LineNr"> 495 </span>  <span class="Conceal">¦</span> press right-arrow  <span class="Comment"># next line</span>
 <span id="L496" class="LineNr"> 496 </span>  ]
 <span id="L497" class="LineNr"> 497 </span>  run [
-<span id="L498" class="LineNr"> 498 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L498" class="LineNr"> 498 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L499" class="LineNr"> 499 </span>  ]
 <span id="L500" class="LineNr"> 500 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L501" class="LineNr"> 501 </span>  <span class="Comment"># type something and ensure it goes where it should</span>
 <span id="L502" class="LineNr"> 502 </span>  assume-console [
-<span id="L503" class="LineNr"> 503 </span>    type <span class="Constant">[0]</span>
+<span id="L503" class="LineNr"> 503 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
 <span id="L504" class="LineNr"> 504 </span>  ]
 <span id="L505" class="LineNr"> 505 </span>  run [
-<span id="L506" class="LineNr"> 506 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L506" class="LineNr"> 506 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L507" class="LineNr"> 507 </span>  ]
 <span id="L508" class="LineNr"> 508 </span>  screen-should-contain [
-<span id="L509" class="LineNr"> 509 </span>   <span class="Constant"> .          .</span>
-<span id="L510" class="LineNr"> 510 </span>   <span class="Constant"> .abc       .</span>
-<span id="L511" class="LineNr"> 511 </span>   <span class="Constant"> .0d        .</span>
-<span id="L512" class="LineNr"> 512 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L513" class="LineNr"> 513 </span>   <span class="Constant"> .          .</span>
+<span id="L509" class="LineNr"> 509 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L510" class="LineNr"> 510 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L511" class="LineNr"> 511 </span>  <span class="Conceal">¦</span><span class="Constant"> .0d        .</span>
+<span id="L512" class="LineNr"> 512 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L513" class="LineNr"> 513 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L514" class="LineNr"> 514 </span>  ]
 <span id="L515" class="LineNr"> 515 </span>  check-trace-count-for-label<span class="Constant"> 2</span>, <span class="Constant">[print-character]</span>  <span class="Comment"># new length of second line</span>
 <span id="L516" class="LineNr"> 516 </span>]
@@ -583,21 +584,21 @@ if ('onhashchange' in window) {
 <span id="L523" class="LineNr"> 523 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">1/left</span>, <span class="Constant">10/right</span>
 <span id="L524" class="LineNr"> 524 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L525" class="LineNr"> 525 </span>  assume-console [
-<span id="L526" class="LineNr"> 526 </span>    press right-arrow
-<span id="L527" class="LineNr"> 527 </span>    press right-arrow
-<span id="L528" class="LineNr"> 528 </span>    press right-arrow
-<span id="L529" class="LineNr"> 529 </span>    press right-arrow  <span class="Comment"># next line</span>
-<span id="L530" class="LineNr"> 530 </span>    type <span class="Constant">[0]</span>
+<span id="L526" class="LineNr"> 526 </span>  <span class="Conceal">¦</span> press right-arrow
+<span id="L527" class="LineNr"> 527 </span>  <span class="Conceal">¦</span> press right-arrow
+<span id="L528" class="LineNr"> 528 </span>  <span class="Conceal">¦</span> press right-arrow
+<span id="L529" class="LineNr"> 529 </span>  <span class="Conceal">¦</span> press right-arrow  <span class="Comment"># next line</span>
+<span id="L530" class="LineNr"> 530 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
 <span id="L531" class="LineNr"> 531 </span>  ]
 <span id="L532" class="LineNr"> 532 </span>  run [
-<span id="L533" class="LineNr"> 533 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L533" class="LineNr"> 533 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L534" class="LineNr"> 534 </span>  ]
 <span id="L535" class="LineNr"> 535 </span>  screen-should-contain [
-<span id="L536" class="LineNr"> 536 </span>   <span class="Constant"> .          .</span>
-<span id="L537" class="LineNr"> 537 </span>   <span class="Constant"> . abc      .</span>
-<span id="L538" class="LineNr"> 538 </span>   <span class="Constant"> . 0d       .</span>
-<span id="L539" class="LineNr"> 539 </span>   <span class="Constant"> . ╌╌╌╌╌╌╌╌╌.</span>
-<span id="L540" class="LineNr"> 540 </span>   <span class="Constant"> .          .</span>
+<span id="L536" class="LineNr"> 536 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L537" class="LineNr"> 537 </span>  <span class="Conceal">¦</span><span class="Constant"> . abc      .</span>
+<span id="L538" class="LineNr"> 538 </span>  <span class="Conceal">¦</span><span class="Constant"> . 0d       .</span>
+<span id="L539" class="LineNr"> 539 </span>  <span class="Conceal">¦</span><span class="Constant"> . ╌╌╌╌╌╌╌╌╌.</span>
+<span id="L540" class="LineNr"> 540 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L541" class="LineNr"> 541 </span>  ]
 <span id="L542" class="LineNr"> 542 </span>]
 <span id="L543" class="LineNr"> 543 </span>
@@ -608,24 +609,24 @@ if ('onhashchange' in window) {
 <span id="L548" class="LineNr"> 548 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L549" class="LineNr"> 549 </span>  $clear-trace
 <span id="L550" class="LineNr"> 550 </span>  assume-console [
-<span id="L551" class="LineNr"> 551 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
-<span id="L552" class="LineNr"> 552 </span>    press right-arrow
+<span id="L551" class="LineNr"> 551 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
+<span id="L552" class="LineNr"> 552 </span>  <span class="Conceal">¦</span> press right-arrow
 <span id="L553" class="LineNr"> 553 </span>  ]
 <span id="L554" class="LineNr"> 554 </span>  run [
-<span id="L555" class="LineNr"> 555 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L556" class="LineNr"> 556 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L557" class="LineNr"> 557 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L555" class="LineNr"> 555 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L556" class="LineNr"> 556 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L557" class="LineNr"> 557 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L558" class="LineNr"> 558 </span>  ]
 <span id="L559" class="LineNr"> 559 </span>  screen-should-contain [
-<span id="L560" class="LineNr"> 560 </span>   <span class="Constant"> .          .</span>
-<span id="L561" class="LineNr"> 561 </span>   <span class="Constant"> .abcd↩     .</span>
-<span id="L562" class="LineNr"> 562 </span>   <span class="Constant"> .ef        .</span>
-<span id="L563" class="LineNr"> 563 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
-<span id="L564" class="LineNr"> 564 </span>   <span class="Constant"> .          .</span>
+<span id="L560" class="LineNr"> 560 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L561" class="LineNr"> 561 </span>  <span class="Conceal">¦</span><span class="Constant"> .abcd↩     .</span>
+<span id="L562" class="LineNr"> 562 </span>  <span class="Conceal">¦</span><span class="Constant"> .ef        .</span>
+<span id="L563" class="LineNr"> 563 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌     .</span>
+<span id="L564" class="LineNr"> 564 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L565" class="LineNr"> 565 </span>  ]
 <span id="L566" class="LineNr"> 566 </span>  memory-should-contain [
-<span id="L567" class="LineNr"> 567 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
-<span id="L568" class="LineNr"> 568 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
+<span id="L567" class="LineNr"> 567 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L568" class="LineNr"> 568 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
 <span id="L569" class="LineNr"> 569 </span>  ]
 <span id="L570" class="LineNr"> 570 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L571" class="LineNr"> 571 </span>]
@@ -639,30 +640,30 @@ if ('onhashchange' in window) {
 <span id="L579" class="LineNr"> 579 </span>  $clear-trace
 <span id="L580" class="LineNr"> 580 </span>  <span class="Comment"># position cursor at last character before wrap and hit right-arrow</span>
 <span id="L581" class="LineNr"> 581 </span>  assume-console [
-<span id="L582" class="LineNr"> 582 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
-<span id="L583" class="LineNr"> 583 </span>    press right-arrow
+<span id="L582" class="LineNr"> 582 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
+<span id="L583" class="LineNr"> 583 </span>  <span class="Conceal">¦</span> press right-arrow
 <span id="L584" class="LineNr"> 584 </span>  ]
 <span id="L585" class="LineNr"> 585 </span>  run [
-<span id="L586" class="LineNr"> 586 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L587" class="LineNr"> 587 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L588" class="LineNr"> 588 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L586" class="LineNr"> 586 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L587" class="LineNr"> 587 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L588" class="LineNr"> 588 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L589" class="LineNr"> 589 </span>  ]
 <span id="L590" class="LineNr"> 590 </span>  memory-should-contain [
-<span id="L591" class="LineNr"> 591 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
-<span id="L592" class="LineNr"> 592 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
+<span id="L591" class="LineNr"> 591 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L592" class="LineNr"> 592 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
 <span id="L593" class="LineNr"> 593 </span>  ]
 <span id="L594" class="LineNr"> 594 </span>  <span class="Comment"># now hit right arrow again</span>
 <span id="L595" class="LineNr"> 595 </span>  assume-console [
-<span id="L596" class="LineNr"> 596 </span>    press right-arrow
+<span id="L596" class="LineNr"> 596 </span>  <span class="Conceal">¦</span> press right-arrow
 <span id="L597" class="LineNr"> 597 </span>  ]
 <span id="L598" class="LineNr"> 598 </span>  run [
-<span id="L599" class="LineNr"> 599 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L600" class="LineNr"> 600 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L601" class="LineNr"> 601 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L599" class="LineNr"> 599 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L600" class="LineNr"> 600 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L601" class="LineNr"> 601 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L602" class="LineNr"> 602 </span>  ]
 <span id="L603" class="LineNr"> 603 </span>  memory-should-contain [
-<span id="L604" class="LineNr"> 604 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
-<span id="L605" class="LineNr"> 605 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L604" class="LineNr"> 604 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L605" class="LineNr"> 605 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L606" class="LineNr"> 606 </span>  ]
 <span id="L607" class="LineNr"> 607 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L608" class="LineNr"> 608 </span>]
@@ -674,24 +675,24 @@ if ('onhashchange' in window) {
 <span id="L614" class="LineNr"> 614 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L615" class="LineNr"> 615 </span>  $clear-trace
 <span id="L616" class="LineNr"> 616 </span>  assume-console [
-<span id="L617" class="LineNr"> 617 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 4</span>
-<span id="L618" class="LineNr"> 618 </span>    press right-arrow
+<span id="L617" class="LineNr"> 617 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 4</span>
+<span id="L618" class="LineNr"> 618 </span>  <span class="Conceal">¦</span> press right-arrow
 <span id="L619" class="LineNr"> 619 </span>  ]
 <span id="L620" class="LineNr"> 620 </span>  run [
-<span id="L621" class="LineNr"> 621 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L622" class="LineNr"> 622 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L623" class="LineNr"> 623 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L621" class="LineNr"> 621 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L622" class="LineNr"> 622 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L623" class="LineNr"> 623 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L624" class="LineNr"> 624 </span>  ]
 <span id="L625" class="LineNr"> 625 </span>  screen-should-contain [
-<span id="L626" class="LineNr"> 626 </span>   <span class="Constant"> .          .</span>
-<span id="L627" class="LineNr"> 627 </span>   <span class="Constant"> . abcd↩    .</span>
-<span id="L628" class="LineNr"> 628 </span>   <span class="Constant"> . ef       .</span>
-<span id="L629" class="LineNr"> 629 </span>   <span class="Constant"> . ╌╌╌╌╌    .</span>
-<span id="L630" class="LineNr"> 630 </span>   <span class="Constant"> .          .</span>
+<span id="L626" class="LineNr"> 626 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L627" class="LineNr"> 627 </span>  <span class="Conceal">¦</span><span class="Constant"> . abcd↩    .</span>
+<span id="L628" class="LineNr"> 628 </span>  <span class="Conceal">¦</span><span class="Constant"> . ef       .</span>
+<span id="L629" class="LineNr"> 629 </span>  <span class="Conceal">¦</span><span class="Constant"> . ╌╌╌╌╌    .</span>
+<span id="L630" class="LineNr"> 630 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L631" class="LineNr"> 631 </span>  ]
 <span id="L632" class="LineNr"> 632 </span>  memory-should-contain [
-<span id="L633" class="LineNr"> 633 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
-<span id="L634" class="LineNr"> 634 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L633" class="LineNr"> 633 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L634" class="LineNr"> 634 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L635" class="LineNr"> 635 </span>  ]
 <span id="L636" class="LineNr"> 636 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L637" class="LineNr"> 637 </span>]
@@ -706,20 +707,20 @@ if ('onhashchange' in window) {
 <span id="L646" class="LineNr"> 646 </span>  $clear-trace
 <span id="L647" class="LineNr"> 647 </span>  <span class="Comment"># move to end of line, press right-arrow, type a character</span>
 <span id="L648" class="LineNr"> 648 </span>  assume-console [
-<span id="L649" class="LineNr"> 649 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
-<span id="L650" class="LineNr"> 650 </span>    press right-arrow
-<span id="L651" class="LineNr"> 651 </span>    type <span class="Constant">[0]</span>
+<span id="L649" class="LineNr"> 649 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
+<span id="L650" class="LineNr"> 650 </span>  <span class="Conceal">¦</span> press right-arrow
+<span id="L651" class="LineNr"> 651 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
 <span id="L652" class="LineNr"> 652 </span>  ]
 <span id="L653" class="LineNr"> 653 </span>  run [
-<span id="L654" class="LineNr"> 654 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L654" class="LineNr"> 654 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L655" class="LineNr"> 655 </span>  ]
 <span id="L656" class="LineNr"> 656 </span>  <span class="Comment"># new character should be in next line</span>
 <span id="L657" class="LineNr"> 657 </span>  screen-should-contain [
-<span id="L658" class="LineNr"> 658 </span>   <span class="Constant"> .          .</span>
-<span id="L659" class="LineNr"> 659 </span>   <span class="Constant"> .abc       .</span>
-<span id="L660" class="LineNr"> 660 </span>   <span class="Constant"> .0d        .</span>
-<span id="L661" class="LineNr"> 661 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L662" class="LineNr"> 662 </span>   <span class="Constant"> .          .</span>
+<span id="L658" class="LineNr"> 658 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L659" class="LineNr"> 659 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L660" class="LineNr"> 660 </span>  <span class="Conceal">¦</span><span class="Constant"> .0d        .</span>
+<span id="L661" class="LineNr"> 661 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L662" class="LineNr"> 662 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L663" class="LineNr"> 663 </span>  ]
 <span id="L664" class="LineNr"> 664 </span>  check-trace-count-for-label<span class="Constant"> 2</span>, <span class="Constant">[print-character]</span>
 <span id="L665" class="LineNr"> 665 </span>]
@@ -735,37 +736,37 @@ if ('onhashchange' in window) {
 <span id="L675" class="LineNr"> 675 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L676" class="LineNr"> 676 </span>  $clear-trace
 <span id="L677" class="LineNr"> 677 </span>  assume-console [
-<span id="L678" class="LineNr"> 678 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 2</span>
-<span id="L679" class="LineNr"> 679 </span>    press left-arrow
-<span id="L680" class="LineNr"> 680 </span>    type <span class="Constant">[0]</span>
+<span id="L678" class="LineNr"> 678 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 2</span>
+<span id="L679" class="LineNr"> 679 </span>  <span class="Conceal">¦</span> press left-arrow
+<span id="L680" class="LineNr"> 680 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
 <span id="L681" class="LineNr"> 681 </span>  ]
 <span id="L682" class="LineNr"> 682 </span>  run [
-<span id="L683" class="LineNr"> 683 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L683" class="LineNr"> 683 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L684" class="LineNr"> 684 </span>  ]
 <span id="L685" class="LineNr"> 685 </span>  screen-should-contain [
-<span id="L686" class="LineNr"> 686 </span>   <span class="Constant"> .          .</span>
-<span id="L687" class="LineNr"> 687 </span>   <span class="Constant"> .a0bc      .</span>
-<span id="L688" class="LineNr"> 688 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L689" class="LineNr"> 689 </span>   <span class="Constant"> .          .</span>
+<span id="L686" class="LineNr"> 686 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L687" class="LineNr"> 687 </span>  <span class="Conceal">¦</span><span class="Constant"> .a0bc      .</span>
+<span id="L688" class="LineNr"> 688 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L689" class="LineNr"> 689 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L690" class="LineNr"> 690 </span>  ]
 <span id="L691" class="LineNr"> 691 </span>  check-trace-count-for-label<span class="Constant"> 3</span>, <span class="Constant">[print-character]</span>
 <span id="L692" class="LineNr"> 692 </span>]
 <span id="L693" class="LineNr"> 693 </span>
 <span id="L694" class="LineNr"> 694 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L197'>&lt;handle-special-key&gt;</a></span> [
 <span id="L695" class="LineNr"> 695 </span>  <span class="Delimiter">{</span>
-<span id="L696" class="LineNr"> 696 </span>    move-to-previous-character?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65515/left-arrow</span>
-<span id="L697" class="LineNr"> 697 </span>    <span class="muControl">break-unless</span> move-to-previous-character?
-<span id="L698" class="LineNr"> 698 </span>    trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[left arrow]</span>
-<span id="L699" class="LineNr"> 699 </span>    <span class="Comment"># if not at start of text (before-cursor at § sentinel)</span>
-<span id="L700" class="LineNr"> 700 </span>    <a href='../065duplex_list.mu.html#L36'>prev</a>:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> before-cursor
-<span id="L701" class="LineNr"> 701 </span>    <span class="muControl">return-unless</span> <a href='../065duplex_list.mu.html#L36'>prev</a>, <span class="Constant">0/don't-render</span>
-<span id="L702" class="LineNr"> 702 </span><span class="Constant">    &lt;move-cursor-begin&gt;</span>
-<span id="L703" class="LineNr"> 703 </span>    go-render? <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L130'>move-cursor-coordinates-left</a> editor
-<span id="L704" class="LineNr"> 704 </span>    before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
-<span id="L705" class="LineNr"> 705 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
-<span id="L706" class="LineNr"> 706 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">1/left-arrow</span>
-<span id="L707" class="LineNr"> 707 </span><span class="Constant">    &lt;move-cursor-end&gt;</span>
-<span id="L708" class="LineNr"> 708 </span>    <span class="muControl">return</span>
+<span id="L696" class="LineNr"> 696 </span>  <span class="Conceal">¦</span> move-to-previous-character?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65515/left-arrow</span>
+<span id="L697" class="LineNr"> 697 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> move-to-previous-character?
+<span id="L698" class="LineNr"> 698 </span>  <span class="Conceal">¦</span> trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[left arrow]</span>
+<span id="L699" class="LineNr"> 699 </span>  <span class="Conceal">¦</span> <span class="Comment"># if not at start of text (before-cursor at § sentinel)</span>
+<span id="L700" class="LineNr"> 700 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a>:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> before-cursor
+<span id="L701" class="LineNr"> 701 </span>  <span class="Conceal">¦</span> <span class="muControl">return-unless</span> <a href='../065duplex_list.mu.html#L36'>prev</a>, <span class="Constant">0/don't-render</span>
+<span id="L702" class="LineNr"> 702 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-begin&gt;</span>
+<span id="L703" class="LineNr"> 703 </span>  <span class="Conceal">¦</span> go-render? <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L130'>move-cursor-coordinates-left</a> editor
+<span id="L704" class="LineNr"> 704 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L705" class="LineNr"> 705 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
+<span id="L706" class="LineNr"> 706 </span>  <span class="Conceal">¦</span> undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">1/left-arrow</span>
+<span id="L707" class="LineNr"> 707 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-end&gt;</span>
+<span id="L708" class="LineNr"> 708 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
 <span id="L709" class="LineNr"> 709 </span>  <span class="Delimiter">}</span>
 <span id="L710" class="LineNr"> 710 </span>]
 <span id="L711" class="LineNr"> 711 </span>
@@ -780,17 +781,17 @@ if ('onhashchange' in window) {
 <span id="L720" class="LineNr"> 720 </span>  $clear-trace
 <span id="L721" class="LineNr"> 721 </span>  <span class="Comment"># position cursor at start of second line (so there's no previous newline)</span>
 <span id="L722" class="LineNr"> 722 </span>  assume-console [
-<span id="L723" class="LineNr"> 723 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
-<span id="L724" class="LineNr"> 724 </span>    press left-arrow
+<span id="L723" class="LineNr"> 723 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
+<span id="L724" class="LineNr"> 724 </span>  <span class="Conceal">¦</span> press left-arrow
 <span id="L725" class="LineNr"> 725 </span>  ]
 <span id="L726" class="LineNr"> 726 </span>  run [
-<span id="L727" class="LineNr"> 727 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L728" class="LineNr"> 728 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L729" class="LineNr"> 729 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
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+<span id="L728" class="LineNr"> 728 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L729" class="LineNr"> 729 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L730" class="LineNr"> 730 </span>  ]
 <span id="L731" class="LineNr"> 731 </span>  memory-should-contain [
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-<span id="L733" class="LineNr"> 733 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L732" class="LineNr"> 732 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L733" class="LineNr"> 733 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
 <span id="L734" class="LineNr"> 734 </span>  ]
 <span id="L735" class="LineNr"> 735 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L736" class="LineNr"> 736 </span>]
@@ -808,19 +809,19 @@ if ('onhashchange' in window) {
 <span id="L748" class="LineNr"> 748 </span>  <span class="Comment"># position cursor further down (so there's a newline before the character at</span>
 <span id="L749" class="LineNr"> 749 </span>  <span class="Comment"># the cursor)</span>
 <span id="L750" class="LineNr"> 750 </span>  assume-console [
-<span id="L751" class="LineNr"> 751 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L752" class="LineNr"> 752 </span>    press left-arrow
-<span id="L753" class="LineNr"> 753 </span>    type <span class="Constant">[0]</span>
+<span id="L751" class="LineNr"> 751 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L752" class="LineNr"> 752 </span>  <span class="Conceal">¦</span> press left-arrow
+<span id="L753" class="LineNr"> 753 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
 <span id="L754" class="LineNr"> 754 </span>  ]
 <span id="L755" class="LineNr"> 755 </span>  run [
-<span id="L756" class="LineNr"> 756 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L756" class="LineNr"> 756 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L757" class="LineNr"> 757 </span>  ]
 <span id="L758" class="LineNr"> 758 </span>  screen-should-contain [
-<span id="L759" class="LineNr"> 759 </span>   <span class="Constant"> .          .</span>
-<span id="L760" class="LineNr"> 760 </span>   <span class="Constant"> .abc       .</span>
-<span id="L761" class="LineNr"> 761 </span>   <span class="Constant"> .def0      .</span>
-<span id="L762" class="LineNr"> 762 </span>   <span class="Constant"> .g         .</span>
-<span id="L763" class="LineNr"> 763 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L759" class="LineNr"> 759 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L760" class="LineNr"> 760 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L761" class="LineNr"> 761 </span>  <span class="Conceal">¦</span><span class="Constant"> .def0      .</span>
+<span id="L762" class="LineNr"> 762 </span>  <span class="Conceal">¦</span><span class="Constant"> .g         .</span>
+<span id="L763" class="LineNr"> 763 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
 <span id="L764" class="LineNr"> 764 </span>  ]
 <span id="L765" class="LineNr"> 765 </span>  check-trace-count-for-label<span class="Constant"> 1</span>, <span class="Constant">[print-character]</span>  <span class="Comment"># just the '0'</span>
 <span id="L766" class="LineNr"> 766 </span>]
@@ -836,20 +837,20 @@ if ('onhashchange' in window) {
 <span id="L776" class="LineNr"> 776 </span>  $clear-trace
 <span id="L777" class="LineNr"> 777 </span>  <span class="Comment"># position cursor at start of text, press left-arrow, then type a character</span>
 <span id="L778" class="LineNr"> 778 </span>  assume-console [
-<span id="L779" class="LineNr"> 779 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 0</span>
-<span id="L780" class="LineNr"> 780 </span>    press left-arrow
-<span id="L781" class="LineNr"> 781 </span>    type <span class="Constant">[0]</span>
+<span id="L779" class="LineNr"> 779 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 0</span>
+<span id="L780" class="LineNr"> 780 </span>  <span class="Conceal">¦</span> press left-arrow
+<span id="L781" class="LineNr"> 781 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
 <span id="L782" class="LineNr"> 782 </span>  ]
 <span id="L783" class="LineNr"> 783 </span>  run [
-<span id="L784" class="LineNr"> 784 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L784" class="LineNr"> 784 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L785" class="LineNr"> 785 </span>  ]
 <span id="L786" class="LineNr"> 786 </span>  <span class="Comment"># left-arrow should have had no effect</span>
 <span id="L787" class="LineNr"> 787 </span>  screen-should-contain [
-<span id="L788" class="LineNr"> 788 </span>   <span class="Constant"> .          .</span>
-<span id="L789" class="LineNr"> 789 </span>   <span class="Constant"> .0abc      .</span>
-<span id="L790" class="LineNr"> 790 </span>   <span class="Constant"> .def       .</span>
-<span id="L791" class="LineNr"> 791 </span>   <span class="Constant"> .g         .</span>
-<span id="L792" class="LineNr"> 792 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L788" class="LineNr"> 788 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L789" class="LineNr"> 789 </span>  <span class="Conceal">¦</span><span class="Constant"> .0abc      .</span>
+<span id="L790" class="LineNr"> 790 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
+<span id="L791" class="LineNr"> 791 </span>  <span class="Conceal">¦</span><span class="Constant"> .g         .</span>
+<span id="L792" class="LineNr"> 792 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
 <span id="L793" class="LineNr"> 793 </span>  ]
 <span id="L794" class="LineNr"> 794 </span>  check-trace-count-for-label<span class="Constant"> 4</span>, <span class="Constant">[print-character]</span>  <span class="Comment"># length of first line</span>
 <span id="L795" class="LineNr"> 795 </span>]
@@ -866,19 +867,19 @@ if ('onhashchange' in window) {
 <span id="L806" class="LineNr"> 806 </span>  $clear-trace
 <span id="L807" class="LineNr"> 807 </span>  <span class="Comment"># position cursor right after empty line</span>
 <span id="L808" class="LineNr"> 808 </span>  assume-console [
-<span id="L809" class="LineNr"> 809 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L810" class="LineNr"> 810 </span>    press left-arrow
-<span id="L811" class="LineNr"> 811 </span>    type <span class="Constant">[0]</span>
+<span id="L809" class="LineNr"> 809 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L810" class="LineNr"> 810 </span>  <span class="Conceal">¦</span> press left-arrow
+<span id="L811" class="LineNr"> 811 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
 <span id="L812" class="LineNr"> 812 </span>  ]
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-<span id="L814" class="LineNr"> 814 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L814" class="LineNr"> 814 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L815" class="LineNr"> 815 </span>  ]
 <span id="L816" class="LineNr"> 816 </span>  screen-should-contain [
-<span id="L817" class="LineNr"> 817 </span>   <span class="Constant"> .          .</span>
-<span id="L818" class="LineNr"> 818 </span>   <span class="Constant"> .abc       .</span>
-<span id="L819" class="LineNr"> 819 </span>   <span class="Constant"> .0         .</span>
-<span id="L820" class="LineNr"> 820 </span>   <span class="Constant"> .d         .</span>
-<span id="L821" class="LineNr"> 821 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L817" class="LineNr"> 817 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L818" class="LineNr"> 818 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L819" class="LineNr"> 819 </span>  <span class="Conceal">¦</span><span class="Constant"> .0         .</span>
+<span id="L820" class="LineNr"> 820 </span>  <span class="Conceal">¦</span><span class="Constant"> .d         .</span>
+<span id="L821" class="LineNr"> 821 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
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 <span id="L823" class="LineNr"> 823 </span>  check-trace-count-for-label<span class="Constant"> 1</span>, <span class="Constant">[print-character]</span>  <span class="Comment"># just the '0'</span>
 <span id="L824" class="LineNr"> 824 </span>]
@@ -891,25 +892,25 @@ if ('onhashchange' in window) {
 <span id="L831" class="LineNr"> 831 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L832" class="LineNr"> 832 </span>  $clear-trace
 <span id="L833" class="LineNr"> 833 </span>  screen-should-contain [
-<span id="L834" class="LineNr"> 834 </span>   <span class="Constant"> .          .</span>
-<span id="L835" class="LineNr"> 835 </span>   <span class="Constant"> .abcd↩     .</span>
-<span id="L836" class="LineNr"> 836 </span>   <span class="Constant"> .ef        .</span>
-<span id="L837" class="LineNr"> 837 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
-<span id="L838" class="LineNr"> 838 </span>   <span class="Constant"> .          .</span>
+<span id="L834" class="LineNr"> 834 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L835" class="LineNr"> 835 </span>  <span class="Conceal">¦</span><span class="Constant"> .abcd↩     .</span>
+<span id="L836" class="LineNr"> 836 </span>  <span class="Conceal">¦</span><span class="Constant"> .ef        .</span>
+<span id="L837" class="LineNr"> 837 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌     .</span>
+<span id="L838" class="LineNr"> 838 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L839" class="LineNr"> 839 </span>  ]
 <span id="L840" class="LineNr"> 840 </span>  <span class="Comment"># position cursor right after empty line</span>
 <span id="L841" class="LineNr"> 841 </span>  assume-console [
-<span id="L842" class="LineNr"> 842 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
-<span id="L843" class="LineNr"> 843 </span>    press left-arrow
+<span id="L842" class="LineNr"> 842 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
+<span id="L843" class="LineNr"> 843 </span>  <span class="Conceal">¦</span> press left-arrow
 <span id="L844" class="LineNr"> 844 </span>  ]
 <span id="L845" class="LineNr"> 845 </span>  run [
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-<span id="L847" class="LineNr"> 847 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L848" class="LineNr"> 848 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L846" class="LineNr"> 846 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L847" class="LineNr"> 847 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L848" class="LineNr"> 848 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L849" class="LineNr"> 849 </span>  ]
 <span id="L850" class="LineNr"> 850 </span>  memory-should-contain [
-<span id="L851" class="LineNr"> 851 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># previous row</span>
-<span id="L852" class="LineNr"> 852 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>  <span class="Comment"># right margin except wrap icon</span>
+<span id="L851" class="LineNr"> 851 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># previous row</span>
+<span id="L852" class="LineNr"> 852 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>  <span class="Comment"># right margin except wrap icon</span>
 <span id="L853" class="LineNr"> 853 </span>  ]
 <span id="L854" class="LineNr"> 854 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L855" class="LineNr"> 855 </span>]
@@ -924,25 +925,25 @@ if ('onhashchange' in window) {
 <span id="L864" class="LineNr"> 864 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L865" class="LineNr"> 865 </span>  $clear-trace
 <span id="L866" class="LineNr"> 866 </span>  screen-should-contain [
-<span id="L867" class="LineNr"> 867 </span>   <span class="Constant"> .          .</span>
-<span id="L868" class="LineNr"> 868 </span>   <span class="Constant"> .abcd↩     .</span>
-<span id="L869" class="LineNr"> 869 </span>   <span class="Constant"> .ef        .</span>
-<span id="L870" class="LineNr"> 870 </span>   <span class="Constant"> .g         .</span>
-<span id="L871" class="LineNr"> 871 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
+<span id="L867" class="LineNr"> 867 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L868" class="LineNr"> 868 </span>  <span class="Conceal">¦</span><span class="Constant"> .abcd↩     .</span>
+<span id="L869" class="LineNr"> 869 </span>  <span class="Conceal">¦</span><span class="Constant"> .ef        .</span>
+<span id="L870" class="LineNr"> 870 </span>  <span class="Conceal">¦</span><span class="Constant"> .g         .</span>
+<span id="L871" class="LineNr"> 871 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌     .</span>
 <span id="L872" class="LineNr"> 872 </span>  ]
 <span id="L873" class="LineNr"> 873 </span>  <span class="Comment"># position cursor right after empty line</span>
 <span id="L874" class="LineNr"> 874 </span>  assume-console [
-<span id="L875" class="LineNr"> 875 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L876" class="LineNr"> 876 </span>    press left-arrow
+<span id="L875" class="LineNr"> 875 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L876" class="LineNr"> 876 </span>  <span class="Conceal">¦</span> press left-arrow
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-<span id="L879" class="LineNr"> 879 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L880" class="LineNr"> 880 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L881" class="LineNr"> 881 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L879" class="LineNr"> 879 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L880" class="LineNr"> 880 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L881" class="LineNr"> 881 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L882" class="LineNr"> 882 </span>  ]
 <span id="L883" class="LineNr"> 883 </span>  memory-should-contain [
-<span id="L884" class="LineNr"> 884 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>  <span class="Comment"># previous row</span>
-<span id="L885" class="LineNr"> 885 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>  <span class="Comment"># end of wrapped line</span>
+<span id="L884" class="LineNr"> 884 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>  <span class="Comment"># previous row</span>
+<span id="L885" class="LineNr"> 885 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>  <span class="Comment"># end of wrapped line</span>
 <span id="L886" class="LineNr"> 886 </span>  ]
 <span id="L887" class="LineNr"> 887 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L888" class="LineNr"> 888 </span>]
@@ -957,25 +958,25 @@ if ('onhashchange' in window) {
 <span id="L897" class="LineNr"> 897 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L898" class="LineNr"> 898 </span>  $clear-trace
 <span id="L899" class="LineNr"> 899 </span>  screen-should-contain [
-<span id="L900" class="LineNr"> 900 </span>   <span class="Constant"> .          .</span>
-<span id="L901" class="LineNr"> 901 </span>   <span class="Constant"> .abcd      .</span>
-<span id="L902" class="LineNr"> 902 </span>   <span class="Constant"> .e         .</span>
-<span id="L903" class="LineNr"> 903 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
-<span id="L904" class="LineNr"> 904 </span>   <span class="Constant"> .          .</span>
+<span id="L900" class="LineNr"> 900 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L901" class="LineNr"> 901 </span>  <span class="Conceal">¦</span><span class="Constant"> .abcd      .</span>
+<span id="L902" class="LineNr"> 902 </span>  <span class="Conceal">¦</span><span class="Constant"> .e         .</span>
+<span id="L903" class="LineNr"> 903 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌     .</span>
+<span id="L904" class="LineNr"> 904 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L905" class="LineNr"> 905 </span>  ]
 <span id="L906" class="LineNr"> 906 </span>  <span class="Comment"># position cursor right after empty line</span>
 <span id="L907" class="LineNr"> 907 </span>  assume-console [
-<span id="L908" class="LineNr"> 908 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
-<span id="L909" class="LineNr"> 909 </span>    press left-arrow
+<span id="L908" class="LineNr"> 908 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
+<span id="L909" class="LineNr"> 909 </span>  <span class="Conceal">¦</span> press left-arrow
 <span id="L910" class="LineNr"> 910 </span>  ]
 <span id="L911" class="LineNr"> 911 </span>  run [
-<span id="L912" class="LineNr"> 912 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L913" class="LineNr"> 913 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L914" class="LineNr"> 914 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L912" class="LineNr"> 912 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L913" class="LineNr"> 913 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L914" class="LineNr"> 914 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L915" class="LineNr"> 915 </span>  ]
 <span id="L916" class="LineNr"> 916 </span>  memory-should-contain [
-<span id="L917" class="LineNr"> 917 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># previous row</span>
-<span id="L918" class="LineNr"> 918 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>  <span class="Comment"># end of wrapped line</span>
+<span id="L917" class="LineNr"> 917 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># previous row</span>
+<span id="L918" class="LineNr"> 918 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>  <span class="Comment"># end of wrapped line</span>
 <span id="L919" class="LineNr"> 919 </span>  ]
 <span id="L920" class="LineNr"> 920 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L921" class="LineNr"> 921 </span>]
@@ -993,43 +994,43 @@ if ('onhashchange' in window) {
 <span id="L933" class="LineNr"> 933 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L934" class="LineNr"> 934 </span>  $clear-trace
 <span id="L935" class="LineNr"> 935 </span>  assume-console [
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-<span id="L937" class="LineNr"> 937 </span>    press up-arrow
+<span id="L936" class="LineNr"> 936 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
+<span id="L937" class="LineNr"> 937 </span>  <span class="Conceal">¦</span> press up-arrow
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+<span id="L940" class="LineNr"> 940 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L941" class="LineNr"> 941 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L942" class="LineNr"> 942 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L943" class="LineNr"> 943 </span>  ]
 <span id="L944" class="LineNr"> 944 </span>  memory-should-contain [
-<span id="L945" class="LineNr"> 945 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L946" class="LineNr"> 946 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L945" class="LineNr"> 945 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L946" class="LineNr"> 946 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L947" class="LineNr"> 947 </span>  ]
 <span id="L948" class="LineNr"> 948 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L949" class="LineNr"> 949 </span>  assume-console [
-<span id="L950" class="LineNr"> 950 </span>    type <span class="Constant">[0]</span>
+<span id="L950" class="LineNr"> 950 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
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 <span id="L952" class="LineNr"> 952 </span>  run [
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+<span id="L953" class="LineNr"> 953 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L954" class="LineNr"> 954 </span>  ]
 <span id="L955" class="LineNr"> 955 </span>  screen-should-contain [
-<span id="L956" class="LineNr"> 956 </span>   <span class="Constant"> .          .</span>
-<span id="L957" class="LineNr"> 957 </span>   <span class="Constant"> .a0bc      .</span>
-<span id="L958" class="LineNr"> 958 </span>   <span class="Constant"> .def       .</span>
-<span id="L959" class="LineNr"> 959 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L960" class="LineNr"> 960 </span>   <span class="Constant"> .          .</span>
+<span id="L956" class="LineNr"> 956 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L957" class="LineNr"> 957 </span>  <span class="Conceal">¦</span><span class="Constant"> .a0bc      .</span>
+<span id="L958" class="LineNr"> 958 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
+<span id="L959" class="LineNr"> 959 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L960" class="LineNr"> 960 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L961" class="LineNr"> 961 </span>  ]
 <span id="L962" class="LineNr"> 962 </span>]
 <span id="L963" class="LineNr"> 963 </span>
 <span id="L964" class="LineNr"> 964 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L197'>&lt;handle-special-key&gt;</a></span> [
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-<span id="L967" class="LineNr"> 967 </span>    <span class="muControl">break-unless</span> move-to-previous-line?
-<span id="L968" class="LineNr"> 968 </span><span class="Constant">    &lt;move-cursor-begin&gt;</span>
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-<span id="L970" class="LineNr"> 970 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">3/up-arrow</span>
-<span id="L971" class="LineNr"> 971 </span><span class="Constant">    &lt;move-cursor-end&gt;</span>
-<span id="L972" class="LineNr"> 972 </span>    <span class="muControl">return</span>
+<span id="L966" class="LineNr"> 966 </span>  <span class="Conceal">¦</span> move-to-previous-line?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65517/up-arrow</span>
+<span id="L967" class="LineNr"> 967 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> move-to-previous-line?
+<span id="L968" class="LineNr"> 968 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-begin&gt;</span>
+<span id="L969" class="LineNr"> 969 </span>  <span class="Conceal">¦</span> go-render? <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L976'>move-to-previous-line</a> editor
+<span id="L970" class="LineNr"> 970 </span>  <span class="Conceal">¦</span> undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">3/up-arrow</span>
+<span id="L971" class="LineNr"> 971 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-end&gt;</span>
+<span id="L972" class="LineNr"> 972 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
 <span id="L973" class="LineNr"> 973 </span>  <span class="Delimiter">}</span>
 <span id="L974" class="LineNr"> 974 </span>]
 <span id="L975" class="LineNr"> 975 </span>
@@ -1044,57 +1045,57 @@ if ('onhashchange' in window) {
 <span id="L984" class="LineNr"> 984 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
 <span id="L985" class="LineNr"> 985 </span>  already-at-top?:bool <span class="Special">&lt;-</span> lesser-or-equal cursor-row, <span class="Constant">1/top</span>
 <span id="L986" class="LineNr"> 986 </span>  <span class="Delimiter">{</span>
-<span id="L987" class="LineNr"> 987 </span>    <span class="Comment"># if cursor not at top, move it</span>
-<span id="L988" class="LineNr"> 988 </span>    <span class="muControl">break-if</span> already-at-top?
-<span id="L989" class="LineNr"> 989 </span>    <span class="Comment"># if not at newline, move to start of line (previous newline)</span>
-<span id="L990" class="LineNr"> 990 </span>    <span class="Comment"># then scan back another line</span>
-<span id="L991" class="LineNr"> 991 </span>    <span class="Comment"># if either step fails, give up without modifying cursor or coordinates</span>
-<span id="L992" class="LineNr"> 992 </span>    curr:&amp;:duplex-list:char <span class="Special">&lt;-</span> copy before-cursor
-<span id="L993" class="LineNr"> 993 </span>    <span class="Delimiter">{</span>
-<span id="L994" class="LineNr"> 994 </span>      old:&amp;:duplex-list:char <span class="Special">&lt;-</span> copy curr
-<span id="L995" class="LineNr"> 995 </span>      c2:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
-<span id="L996" class="LineNr"> 996 </span>      at-newline?:bool <span class="Special">&lt;-</span> equal c2, <span class="Constant">10/newline</span>
-<span id="L997" class="LineNr"> 997 </span>      <span class="muControl">break-if</span> at-newline?
-<span id="L998" class="LineNr"> 998 </span>      curr:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2367'>before-previous-line</a> curr, editor
-<span id="L999" class="LineNr"> 999 </span>      no-motion?:bool <span class="Special">&lt;-</span> equal curr, old
-<span id="L1000" class="LineNr">1000 </span>      <span class="muControl">return-if</span> no-motion?
-<span id="L1001" class="LineNr">1001 </span>    <span class="Delimiter">}</span>
-<span id="L1002" class="LineNr">1002 </span>    <span class="Delimiter">{</span>
-<span id="L1003" class="LineNr">1003 </span>      old <span class="Special">&lt;-</span> copy curr
-<span id="L1004" class="LineNr">1004 </span>      curr <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2367'>before-previous-line</a> curr, editor
-<span id="L1005" class="LineNr">1005 </span>      no-motion?:bool <span class="Special">&lt;-</span> equal curr, old
-<span id="L1006" class="LineNr">1006 </span>      <span class="muControl">return-if</span> no-motion?
-<span id="L1007" class="LineNr">1007 </span>    <span class="Delimiter">}</span>
-<span id="L1008" class="LineNr">1008 </span>    before-cursor <span class="Special">&lt;-</span> copy curr
-<span id="L1009" class="LineNr">1009 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
-<span id="L1010" class="LineNr">1010 </span>    cursor-row <span class="Special">&lt;-</span> subtract cursor-row,<span class="Constant"> 1</span>
-<span id="L1011" class="LineNr">1011 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
-<span id="L1012" class="LineNr">1012 </span>    <span class="Comment"># scan ahead to right column or until end of line</span>
-<span id="L1013" class="LineNr">1013 </span>    target-column:num <span class="Special">&lt;-</span> copy cursor-column
-<span id="L1014" class="LineNr">1014 </span>    cursor-column <span class="Special">&lt;-</span> copy left
-<span id="L1015" class="LineNr">1015 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
-<span id="L1016" class="LineNr">1016 </span>    <span class="Delimiter">{</span>
-<span id="L1017" class="LineNr">1017 </span>      done?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-column, target-column
-<span id="L1018" class="LineNr">1018 </span>      <span class="muControl">break-if</span> done?
-<span id="L1019" class="LineNr">1019 </span>      curr:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
-<span id="L1020" class="LineNr">1020 </span>      <span class="muControl">break-unless</span> curr
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-<span id="L1022" class="LineNr">1022 </span>      at-newline?:bool <span class="Special">&lt;-</span> equal currc, <span class="Constant">10/newline</span>
-<span id="L1023" class="LineNr">1023 </span>      <span class="muControl">break-if</span> at-newline?
-<span id="L1024" class="LineNr">1024 </span>      <span class="Comment">#</span>
-<span id="L1025" class="LineNr">1025 </span>      before-cursor <span class="Special">&lt;-</span> copy curr
-<span id="L1026" class="LineNr">1026 </span>      *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
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-<span id="L1028" class="LineNr">1028 </span>      *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
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-<span id="L1030" class="LineNr">1030 </span>    <span class="Delimiter">}</span>
-<span id="L1031" class="LineNr">1031 </span>    <span class="muControl">return</span>
+<span id="L987" class="LineNr"> 987 </span>  <span class="Conceal">¦</span> <span class="Comment"># if cursor not at top, move it</span>
+<span id="L988" class="LineNr"> 988 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> already-at-top?
+<span id="L989" class="LineNr"> 989 </span>  <span class="Conceal">¦</span> <span class="Comment"># if not at newline, move to start of line (previous newline)</span>
+<span id="L990" class="LineNr"> 990 </span>  <span class="Conceal">¦</span> <span class="Comment"># then scan back another line</span>
+<span id="L991" class="LineNr"> 991 </span>  <span class="Conceal">¦</span> <span class="Comment"># if either step fails, give up without modifying cursor or coordinates</span>
+<span id="L992" class="LineNr"> 992 </span>  <span class="Conceal">¦</span> curr:&amp;:duplex-list:char <span class="Special">&lt;-</span> copy before-cursor
+<span id="L993" class="LineNr"> 993 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L994" class="LineNr"> 994 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> old:&amp;:duplex-list:char <span class="Special">&lt;-</span> copy curr
+<span id="L995" class="LineNr"> 995 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> c2:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
+<span id="L996" class="LineNr"> 996 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-newline?:bool <span class="Special">&lt;-</span> equal c2, <span class="Constant">10/newline</span>
+<span id="L997" class="LineNr"> 997 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-newline?
+<span id="L998" class="LineNr"> 998 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2367'>before-previous-line</a> curr, editor
+<span id="L999" class="LineNr"> 999 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> no-motion?:bool <span class="Special">&lt;-</span> equal curr, old
+<span id="L1000" class="LineNr">1000 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">return-if</span> no-motion?
+<span id="L1001" class="LineNr">1001 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L1002" class="LineNr">1002 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L1003" class="LineNr">1003 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> old <span class="Special">&lt;-</span> copy curr
+<span id="L1004" class="LineNr">1004 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2367'>before-previous-line</a> curr, editor
+<span id="L1005" class="LineNr">1005 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> no-motion?:bool <span class="Special">&lt;-</span> equal curr, old
+<span id="L1006" class="LineNr">1006 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">return-if</span> no-motion?
+<span id="L1007" class="LineNr">1007 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L1008" class="LineNr">1008 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy curr
+<span id="L1009" class="LineNr">1009 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
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+<span id="L1011" class="LineNr">1011 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
+<span id="L1012" class="LineNr">1012 </span>  <span class="Conceal">¦</span> <span class="Comment"># scan ahead to right column or until end of line</span>
+<span id="L1013" class="LineNr">1013 </span>  <span class="Conceal">¦</span> target-column:num <span class="Special">&lt;-</span> copy cursor-column
+<span id="L1014" class="LineNr">1014 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> copy left
+<span id="L1015" class="LineNr">1015 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
+<span id="L1016" class="LineNr">1016 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L1017" class="LineNr">1017 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> done?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-column, target-column
+<span id="L1018" class="LineNr">1018 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
+<span id="L1019" class="LineNr">1019 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L1020" class="LineNr">1020 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> curr
+<span id="L1021" class="LineNr">1021 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> currc:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
+<span id="L1022" class="LineNr">1022 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-newline?:bool <span class="Special">&lt;-</span> equal currc, <span class="Constant">10/newline</span>
+<span id="L1023" class="LineNr">1023 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-newline?
+<span id="L1024" class="LineNr">1024 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment">#</span>
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+<span id="L1028" class="LineNr">1028 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
+<span id="L1029" class="LineNr">1029 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span>
+<span id="L1030" class="LineNr">1030 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L1031" class="LineNr">1031 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
 <span id="L1032" class="LineNr">1032 </span>  <span class="Delimiter">}</span>
 <span id="L1033" class="LineNr">1033 </span>  <span class="Delimiter">{</span>
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-<span id="L1035" class="LineNr">1035 </span>    <span class="muControl">break-unless</span> already-at-top?
-<span id="L1036" class="LineNr">1036 </span><span class="Constant">    &lt;scroll-up&gt;</span>
-<span id="L1037" class="LineNr">1037 </span>    <span class="muControl">return</span> <span class="Constant">1/go-render</span>
+<span id="L1034" class="LineNr">1034 </span>  <span class="Conceal">¦</span> <span class="Comment"># if cursor already at top, scroll up</span>
+<span id="L1035" class="LineNr">1035 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> already-at-top?
+<span id="L1036" class="LineNr">1036 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;scroll-up&gt;</span>
+<span id="L1037" class="LineNr">1037 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">1/go-render</span>
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 <span id="L1039" class="LineNr">1039 </span>]
 <span id="L1040" class="LineNr">1040 </span>
@@ -1107,31 +1108,31 @@ if ('onhashchange' in window) {
 <span id="L1047" class="LineNr">1047 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L1048" class="LineNr">1048 </span>  $clear-trace
 <span id="L1049" class="LineNr">1049 </span>  assume-console [
-<span id="L1050" class="LineNr">1050 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
-<span id="L1051" class="LineNr">1051 </span>    press up-arrow
+<span id="L1050" class="LineNr">1050 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
+<span id="L1051" class="LineNr">1051 </span>  <span class="Conceal">¦</span> press up-arrow
 <span id="L1052" class="LineNr">1052 </span>  ]
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+<span id="L1054" class="LineNr">1054 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1055" class="LineNr">1055 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L1056" class="LineNr">1056 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1057" class="LineNr">1057 </span>  ]
 <span id="L1058" class="LineNr">1058 </span>  memory-should-contain [
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-<span id="L1060" class="LineNr">1060 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L1059" class="LineNr">1059 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1060" class="LineNr">1060 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
 <span id="L1061" class="LineNr">1061 </span>  ]
 <span id="L1062" class="LineNr">1062 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L1063" class="LineNr">1063 </span>  assume-console [
-<span id="L1064" class="LineNr">1064 </span>    type <span class="Constant">[0]</span>
+<span id="L1064" class="LineNr">1064 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
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+<span id="L1067" class="LineNr">1067 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1068" class="LineNr">1068 </span>  ]
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-<span id="L1074" class="LineNr">1074 </span>   <span class="Constant"> .          .</span>
+<span id="L1070" class="LineNr">1070 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1071" class="LineNr">1071 </span>  <span class="Conceal">¦</span><span class="Constant"> .ab0       .</span>
+<span id="L1072" class="LineNr">1072 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
+<span id="L1073" class="LineNr">1073 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1074" class="LineNr">1074 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
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 <span id="L1076" class="LineNr">1076 </span>]
 <span id="L1077" class="LineNr">1077 </span>
@@ -1144,31 +1145,31 @@ if ('onhashchange' in window) {
 <span id="L1084" class="LineNr">1084 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L1085" class="LineNr">1085 </span>  $clear-trace
 <span id="L1086" class="LineNr">1086 </span>  assume-console [
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-<span id="L1088" class="LineNr">1088 </span>    press up-arrow
+<span id="L1087" class="LineNr">1087 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
+<span id="L1088" class="LineNr">1088 </span>  <span class="Conceal">¦</span> press up-arrow
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+<span id="L1091" class="LineNr">1091 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
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+<span id="L1093" class="LineNr">1093 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1094" class="LineNr">1094 </span>  ]
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-<span id="L1097" class="LineNr">1097 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
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 <span id="L1100" class="LineNr">1100 </span>  assume-console [
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+<span id="L1101" class="LineNr">1101 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
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+<span id="L1104" class="LineNr">1104 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
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-<span id="L1111" class="LineNr">1111 </span>   <span class="Constant"> .          .</span>
+<span id="L1107" class="LineNr">1107 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1108" class="LineNr">1108 </span>  <span class="Conceal">¦</span><span class="Constant"> .0         .</span>
+<span id="L1109" class="LineNr">1109 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
+<span id="L1110" class="LineNr">1110 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1111" class="LineNr">1111 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
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 <span id="L1114" class="LineNr">1114 </span>
@@ -1184,31 +1185,31 @@ if ('onhashchange' in window) {
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-<span id="L1128" class="LineNr">1128 </span>    press up-arrow
+<span id="L1127" class="LineNr">1127 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
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+<span id="L1131" class="LineNr">1131 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
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+<span id="L1133" class="LineNr">1133 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
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-<span id="L1137" class="LineNr">1137 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
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+<span id="L1144" class="LineNr">1144 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
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-<span id="L1150" class="LineNr">1150 </span>   <span class="Constant"> .ghi       .</span>
-<span id="L1151" class="LineNr">1151 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1147" class="LineNr">1147 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1148" class="LineNr">1148 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L1149" class="LineNr">1149 </span>  <span class="Conceal">¦</span><span class="Constant"> .0def      .</span>
+<span id="L1150" class="LineNr">1150 </span>  <span class="Conceal">¦</span><span class="Constant"> .ghi       .</span>
+<span id="L1151" class="LineNr">1151 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
 <span id="L1152" class="LineNr">1152 </span>  ]
 <span id="L1153" class="LineNr">1153 </span>]
 <span id="L1154" class="LineNr">1154 </span>
@@ -1224,43 +1225,43 @@ if ('onhashchange' in window) {
 <span id="L1164" class="LineNr">1164 </span>  $clear-trace
 <span id="L1165" class="LineNr">1165 </span>  <span class="Comment"># cursor starts out at (1, 0)</span>
 <span id="L1166" class="LineNr">1166 </span>  assume-console [
-<span id="L1167" class="LineNr">1167 </span>    press down-arrow
+<span id="L1167" class="LineNr">1167 </span>  <span class="Conceal">¦</span> press down-arrow
 <span id="L1168" class="LineNr">1168 </span>  ]
 <span id="L1169" class="LineNr">1169 </span>  run [
-<span id="L1170" class="LineNr">1170 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L1171" class="LineNr">1171 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L1172" class="LineNr">1172 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L1170" class="LineNr">1170 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1171" class="LineNr">1171 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L1172" class="LineNr">1172 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1173" class="LineNr">1173 </span>  ]
 <span id="L1174" class="LineNr">1174 </span>  <span class="Comment"># ..and ends at (2, 0)</span>
 <span id="L1175" class="LineNr">1175 </span>  memory-should-contain [
-<span id="L1176" class="LineNr">1176 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
-<span id="L1177" class="LineNr">1177 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
+<span id="L1176" class="LineNr">1176 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L1177" class="LineNr">1177 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
 <span id="L1178" class="LineNr">1178 </span>  ]
 <span id="L1179" class="LineNr">1179 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L1180" class="LineNr">1180 </span>  assume-console [
-<span id="L1181" class="LineNr">1181 </span>    type <span class="Constant">[0]</span>
+<span id="L1181" class="LineNr">1181 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
 <span id="L1182" class="LineNr">1182 </span>  ]
 <span id="L1183" class="LineNr">1183 </span>  run [
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+<span id="L1184" class="LineNr">1184 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1185" class="LineNr">1185 </span>  ]
 <span id="L1186" class="LineNr">1186 </span>  screen-should-contain [
-<span id="L1187" class="LineNr">1187 </span>   <span class="Constant"> .          .</span>
-<span id="L1188" class="LineNr">1188 </span>   <span class="Constant"> .abc       .</span>
-<span id="L1189" class="LineNr">1189 </span>   <span class="Constant"> .0def      .</span>
-<span id="L1190" class="LineNr">1190 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1191" class="LineNr">1191 </span>   <span class="Constant"> .          .</span>
+<span id="L1187" class="LineNr">1187 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1188" class="LineNr">1188 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L1189" class="LineNr">1189 </span>  <span class="Conceal">¦</span><span class="Constant"> .0def      .</span>
+<span id="L1190" class="LineNr">1190 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1191" class="LineNr">1191 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1192" class="LineNr">1192 </span>  ]
 <span id="L1193" class="LineNr">1193 </span>]
 <span id="L1194" class="LineNr">1194 </span>
 <span id="L1195" class="LineNr">1195 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L197'>&lt;handle-special-key&gt;</a></span> [
 <span id="L1196" class="LineNr">1196 </span>  <span class="Delimiter">{</span>
-<span id="L1197" class="LineNr">1197 </span>    move-to-next-line?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65516/down-arrow</span>
-<span id="L1198" class="LineNr">1198 </span>    <span class="muControl">break-unless</span> move-to-next-line?
-<span id="L1199" class="LineNr">1199 </span><span class="Constant">    &lt;move-cursor-begin&gt;</span>
-<span id="L1200" class="LineNr">1200 </span>    go-render? <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1207'>move-to-next-line</a> editor, <a href='../081print.mu.html#L594'>screen-height</a>
-<span id="L1201" class="LineNr">1201 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">4/down-arrow</span>
-<span id="L1202" class="LineNr">1202 </span><span class="Constant">    &lt;move-cursor-end&gt;</span>
-<span id="L1203" class="LineNr">1203 </span>    <span class="muControl">return</span>
+<span id="L1197" class="LineNr">1197 </span>  <span class="Conceal">¦</span> move-to-next-line?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65516/down-arrow</span>
+<span id="L1198" class="LineNr">1198 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> move-to-next-line?
+<span id="L1199" class="LineNr">1199 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-begin&gt;</span>
+<span id="L1200" class="LineNr">1200 </span>  <span class="Conceal">¦</span> go-render? <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1207'>move-to-next-line</a> editor, <a href='../081print.mu.html#L594'>screen-height</a>
+<span id="L1201" class="LineNr">1201 </span>  <span class="Conceal">¦</span> undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">4/down-arrow</span>
+<span id="L1202" class="LineNr">1202 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-end&gt;</span>
+<span id="L1203" class="LineNr">1203 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
 <span id="L1204" class="LineNr">1204 </span>  <span class="Delimiter">}</span>
 <span id="L1205" class="LineNr">1205 </span>]
 <span id="L1206" class="LineNr">1206 </span>
@@ -1275,43 +1276,43 @@ if ('onhashchange' in window) {
 <span id="L1215" class="LineNr">1215 </span>  last-line:num <span class="Special">&lt;-</span> subtract <a href='../081print.mu.html#L594'>screen-height</a>,<span class="Constant"> 1</span>
 <span id="L1216" class="LineNr">1216 </span>  already-at-bottom?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-row, last-line
 <span id="L1217" class="LineNr">1217 </span>  <span class="Delimiter">{</span>
-<span id="L1218" class="LineNr">1218 </span>    <span class="Comment"># if cursor not at bottom, move it</span>
-<span id="L1219" class="LineNr">1219 </span>    <span class="muControl">break-if</span> already-at-bottom?
-<span id="L1220" class="LineNr">1220 </span>    <span class="Comment"># scan to start of next line, then to right column or until end of line</span>
-<span id="L1221" class="LineNr">1221 </span>    max:num <span class="Special">&lt;-</span> subtract right, left
-<span id="L1222" class="LineNr">1222 </span>    next-line:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1988'>before-start-of-next-line</a> before-cursor, max
-<span id="L1223" class="LineNr">1223 </span>    <span class="Delimiter">{</span>
-<span id="L1224" class="LineNr">1224 </span>      <span class="Comment"># already at end of buffer? try to scroll up (so we can see more</span>
-<span id="L1225" class="LineNr">1225 </span>      <span class="Comment"># warnings or sandboxes below)</span>
-<span id="L1226" class="LineNr">1226 </span>      no-motion?:bool <span class="Special">&lt;-</span> equal next-line, before-cursor
-<span id="L1227" class="LineNr">1227 </span>      <span class="muControl">break-unless</span> no-motion?
-<span id="L1228" class="LineNr">1228 </span>      scroll?:bool <span class="Special">&lt;-</span> greater-than cursor-row,<span class="Constant"> 1</span>
-<span id="L1229" class="LineNr">1229 </span>      <span class="muControl">break-if</span> scroll?, <span class="Constant">+try-to-scroll</span>
-<span id="L1230" class="LineNr">1230 </span>      <span class="muControl">return</span> <span class="Constant">0/don't-render</span>
-<span id="L1231" class="LineNr">1231 </span>    <span class="Delimiter">}</span>
-<span id="L1232" class="LineNr">1232 </span>    cursor-row <span class="Special">&lt;-</span> add cursor-row,<span class="Constant"> 1</span>
-<span id="L1233" class="LineNr">1233 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
-<span id="L1234" class="LineNr">1234 </span>    before-cursor <span class="Special">&lt;-</span> copy next-line
-<span id="L1235" class="LineNr">1235 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
-<span id="L1236" class="LineNr">1236 </span>    target-column:num <span class="Special">&lt;-</span> copy cursor-column
-<span id="L1237" class="LineNr">1237 </span>    cursor-column <span class="Special">&lt;-</span> copy left
-<span id="L1238" class="LineNr">1238 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
-<span id="L1239" class="LineNr">1239 </span>    <span class="Delimiter">{</span>
-<span id="L1240" class="LineNr">1240 </span>      done?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-column, target-column
-<span id="L1241" class="LineNr">1241 </span>      <span class="muControl">break-if</span> done?
-<span id="L1242" class="LineNr">1242 </span>      curr:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
-<span id="L1243" class="LineNr">1243 </span>      <span class="muControl">break-unless</span> curr
-<span id="L1244" class="LineNr">1244 </span>      currc:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
-<span id="L1245" class="LineNr">1245 </span>      at-newline?:bool <span class="Special">&lt;-</span> equal currc, <span class="Constant">10/newline</span>
-<span id="L1246" class="LineNr">1246 </span>      <span class="muControl">break-if</span> at-newline?
-<span id="L1247" class="LineNr">1247 </span>      <span class="Comment">#</span>
-<span id="L1248" class="LineNr">1248 </span>      before-cursor <span class="Special">&lt;-</span> copy curr
-<span id="L1249" class="LineNr">1249 </span>      *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
-<span id="L1250" class="LineNr">1250 </span>      cursor-column <span class="Special">&lt;-</span> add cursor-column,<span class="Constant"> 1</span>
-<span id="L1251" class="LineNr">1251 </span>      *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
-<span id="L1252" class="LineNr">1252 </span>      <span class="muControl">loop</span>
-<span id="L1253" class="LineNr">1253 </span>    <span class="Delimiter">}</span>
-<span id="L1254" class="LineNr">1254 </span>    <span class="muControl">return</span> <span class="Constant">0/don't-render</span>
+<span id="L1218" class="LineNr">1218 </span>  <span class="Conceal">¦</span> <span class="Comment"># if cursor not at bottom, move it</span>
+<span id="L1219" class="LineNr">1219 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> already-at-bottom?
+<span id="L1220" class="LineNr">1220 </span>  <span class="Conceal">¦</span> <span class="Comment"># scan to start of next line, then to right column or until end of line</span>
+<span id="L1221" class="LineNr">1221 </span>  <span class="Conceal">¦</span> max:num <span class="Special">&lt;-</span> subtract right, left
+<span id="L1222" class="LineNr">1222 </span>  <span class="Conceal">¦</span> next-line:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1988'>before-start-of-next-line</a> before-cursor, max
+<span id="L1223" class="LineNr">1223 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L1224" class="LineNr">1224 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># already at end of buffer? try to scroll up (so we can see more</span>
+<span id="L1225" class="LineNr">1225 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># warnings or sandboxes below)</span>
+<span id="L1226" class="LineNr">1226 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> no-motion?:bool <span class="Special">&lt;-</span> equal next-line, before-cursor
+<span id="L1227" class="LineNr">1227 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> no-motion?
+<span id="L1228" class="LineNr">1228 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> scroll?:bool <span class="Special">&lt;-</span> greater-than cursor-row,<span class="Constant"> 1</span>
+<span id="L1229" class="LineNr">1229 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> scroll?, <span class="Constant">+try-to-scroll</span>
+<span id="L1230" class="LineNr">1230 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">0/don't-render</span>
+<span id="L1231" class="LineNr">1231 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L1232" class="LineNr">1232 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> add cursor-row,<span class="Constant"> 1</span>
+<span id="L1233" class="LineNr">1233 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
+<span id="L1234" class="LineNr">1234 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy next-line
+<span id="L1235" class="LineNr">1235 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
+<span id="L1236" class="LineNr">1236 </span>  <span class="Conceal">¦</span> target-column:num <span class="Special">&lt;-</span> copy cursor-column
+<span id="L1237" class="LineNr">1237 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> copy left
+<span id="L1238" class="LineNr">1238 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
+<span id="L1239" class="LineNr">1239 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L1240" class="LineNr">1240 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> done?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-column, target-column
+<span id="L1241" class="LineNr">1241 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
+<span id="L1242" class="LineNr">1242 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L1243" class="LineNr">1243 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> curr
+<span id="L1244" class="LineNr">1244 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> currc:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
+<span id="L1245" class="LineNr">1245 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-newline?:bool <span class="Special">&lt;-</span> equal currc, <span class="Constant">10/newline</span>
+<span id="L1246" class="LineNr">1246 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-newline?
+<span id="L1247" class="LineNr">1247 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment">#</span>
+<span id="L1248" class="LineNr">1248 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy curr
+<span id="L1249" class="LineNr">1249 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
+<span id="L1250" class="LineNr">1250 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> add cursor-column,<span class="Constant"> 1</span>
+<span id="L1251" class="LineNr">1251 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
+<span id="L1252" class="LineNr">1252 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span>
+<span id="L1253" class="LineNr">1253 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L1254" class="LineNr">1254 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">0/don't-render</span>
 <span id="L1255" class="LineNr">1255 </span>  <span class="Delimiter">}</span>
 <span id="L1256" class="LineNr">1256 </span><span class="Constant">  +try-to-scroll</span>
 <span id="L1257" class="LineNr">1257 </span><span class="Constant">  &lt;scroll-down&gt;</span>
@@ -1327,31 +1328,31 @@ if ('onhashchange' in window) {
 <span id="L1267" class="LineNr">1267 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
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 <span id="L1269" class="LineNr">1269 </span>  assume-console [
-<span id="L1270" class="LineNr">1270 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
-<span id="L1271" class="LineNr">1271 </span>    press down-arrow
+<span id="L1270" class="LineNr">1270 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
+<span id="L1271" class="LineNr">1271 </span>  <span class="Conceal">¦</span> press down-arrow
 <span id="L1272" class="LineNr">1272 </span>  ]
 <span id="L1273" class="LineNr">1273 </span>  run [
-<span id="L1274" class="LineNr">1274 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L1275" class="LineNr">1275 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L1276" class="LineNr">1276 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L1274" class="LineNr">1274 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1275" class="LineNr">1275 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L1276" class="LineNr">1276 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1277" class="LineNr">1277 </span>  ]
 <span id="L1278" class="LineNr">1278 </span>  memory-should-contain [
-<span id="L1279" class="LineNr">1279 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
-<span id="L1280" class="LineNr">1280 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L1279" class="LineNr">1279 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L1280" class="LineNr">1280 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
 <span id="L1281" class="LineNr">1281 </span>  ]
 <span id="L1282" class="LineNr">1282 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L1283" class="LineNr">1283 </span>  assume-console [
-<span id="L1284" class="LineNr">1284 </span>    type <span class="Constant">[0]</span>
+<span id="L1284" class="LineNr">1284 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
 <span id="L1285" class="LineNr">1285 </span>  ]
 <span id="L1286" class="LineNr">1286 </span>  run [
-<span id="L1287" class="LineNr">1287 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1287" class="LineNr">1287 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1288" class="LineNr">1288 </span>  ]
 <span id="L1289" class="LineNr">1289 </span>  screen-should-contain [
-<span id="L1290" class="LineNr">1290 </span>   <span class="Constant"> .          .</span>
-<span id="L1291" class="LineNr">1291 </span>   <span class="Constant"> .abc       .</span>
-<span id="L1292" class="LineNr">1292 </span>   <span class="Constant"> .de0       .</span>
-<span id="L1293" class="LineNr">1293 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1294" class="LineNr">1294 </span>   <span class="Constant"> .          .</span>
+<span id="L1290" class="LineNr">1290 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1291" class="LineNr">1291 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L1292" class="LineNr">1292 </span>  <span class="Conceal">¦</span><span class="Constant"> .de0       .</span>
+<span id="L1293" class="LineNr">1293 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1294" class="LineNr">1294 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1295" class="LineNr">1295 </span>  ]
 <span id="L1296" class="LineNr">1296 </span>]
 <span id="L1297" class="LineNr">1297 </span>
@@ -1367,43 +1368,43 @@ if ('onhashchange' in window) {
 <span id="L1307" class="LineNr">1307 </span>  $clear-trace
 <span id="L1308" class="LineNr">1308 </span>  <span class="Comment"># start on second line, press ctrl-a</span>
 <span id="L1309" class="LineNr">1309 </span>  assume-console [
-<span id="L1310" class="LineNr">1310 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
-<span id="L1311" class="LineNr">1311 </span>    press ctrl-a
+<span id="L1310" class="LineNr">1310 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
+<span id="L1311" class="LineNr">1311 </span>  <span class="Conceal">¦</span> press ctrl-a
 <span id="L1312" class="LineNr">1312 </span>  ]
 <span id="L1313" class="LineNr">1313 </span>  run [
-<span id="L1314" class="LineNr">1314 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L1315" class="LineNr">1315 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L1316" class="LineNr">1316 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L1314" class="LineNr">1314 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1315" class="LineNr">1315 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L1316" class="LineNr">1316 </span>  <span class="Conceal">¦</span> 5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1317" class="LineNr">1317 </span>  ]
 <span id="L1318" class="LineNr">1318 </span>  <span class="Comment"># cursor moves to start of line</span>
 <span id="L1319" class="LineNr">1319 </span>  memory-should-contain [
-<span id="L1320" class="LineNr">1320 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
-<span id="L1321" class="LineNr">1321 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
+<span id="L1320" class="LineNr">1320 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L1321" class="LineNr">1321 </span>  <span class="Conceal">¦</span><span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
 <span id="L1322" class="LineNr">1322 </span>  ]
 <span id="L1323" class="LineNr">1323 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L1324" class="LineNr">1324 </span>]
 <span id="L1325" class="LineNr">1325 </span>
 <span id="L1326" class="LineNr">1326 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L183'>&lt;handle-special-character&gt;</a></span> [
 <span id="L1327" class="LineNr">1327 </span>  <span class="Delimiter">{</span>
-<span id="L1328" class="LineNr">1328 </span>    move-to-start-of-line?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">1/ctrl-a</span>
-<span id="L1329" class="LineNr">1329 </span>    <span class="muControl">break-unless</span> move-to-start-of-line?
-<span id="L1330" class="LineNr">1330 </span><span class="Constant">    &lt;move-cursor-begin&gt;</span>
-<span id="L1331" class="LineNr">1331 </span>    <a href='003-shortcuts.mu.html#L1350'>move-to-start-of-line</a> editor
-<span id="L1332" class="LineNr">1332 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
-<span id="L1333" class="LineNr">1333 </span><span class="Constant">    &lt;move-cursor-end&gt;</span>
-<span id="L1334" class="LineNr">1334 </span>    <span class="muControl">return</span> <span class="Constant">0/don't-render</span>
+<span id="L1328" class="LineNr">1328 </span>  <span class="Conceal">¦</span> move-to-start-of-line?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">1/ctrl-a</span>
+<span id="L1329" class="LineNr">1329 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> move-to-start-of-line?
+<span id="L1330" class="LineNr">1330 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-begin&gt;</span>
+<span id="L1331" class="LineNr">1331 </span>  <span class="Conceal">¦</span> <a href='003-shortcuts.mu.html#L1350'>move-to-start-of-line</a> editor
+<span id="L1332" class="LineNr">1332 </span>  <span class="Conceal">¦</span> undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
+<span id="L1333" class="LineNr">1333 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-end&gt;</span>
+<span id="L1334" class="LineNr">1334 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">0/don't-render</span>
 <span id="L1335" class="LineNr">1335 </span>  <span class="Delimiter">}</span>
 <span id="L1336" class="LineNr">1336 </span>]
 <span id="L1337" class="LineNr">1337 </span>
 <span id="L1338" class="LineNr">1338 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L197'>&lt;handle-special-key&gt;</a></span> [
 <span id="L1339" class="LineNr">1339 </span>  <span class="Delimiter">{</span>
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-<span id="L1341" class="LineNr">1341 </span>    <span class="muControl">break-unless</span> move-to-start-of-line?
-<span id="L1342" class="LineNr">1342 </span><span class="Constant">    &lt;move-cursor-begin&gt;</span>
-<span id="L1343" class="LineNr">1343 </span>    <a href='003-shortcuts.mu.html#L1350'>move-to-start-of-line</a> editor
-<span id="L1344" class="LineNr">1344 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
-<span id="L1345" class="LineNr">1345 </span><span class="Constant">    &lt;move-cursor-end&gt;</span>
-<span id="L1346" class="LineNr">1346 </span>    <span class="muControl">return</span> <span class="Constant">0/don't-render</span>
+<span id="L1340" class="LineNr">1340 </span>  <span class="Conceal">¦</span> move-to-start-of-line?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65521/home</span>
+<span id="L1341" class="LineNr">1341 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> move-to-start-of-line?
+<span id="L1342" class="LineNr">1342 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-begin&gt;</span>
+<span id="L1343" class="LineNr">1343 </span>  <span class="Conceal">¦</span> <a href='003-shortcuts.mu.html#L1350'>move-to-start-of-line</a> editor
+<span id="L1344" class="LineNr">1344 </span>  <span class="Conceal">¦</span> undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
+<span id="L1345" class="LineNr">1345 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-end&gt;</span>
+<span id="L1346" class="LineNr">1346 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">0/don't-render</span>
 <span id="L1347" class="LineNr">1347 </span>  <span class="Delimiter">}</span>
 <span id="L1348" class="LineNr">1348 </span>]
 <span id="L1349" class="LineNr">1349 </span>
@@ -1419,15 +1420,15 @@ if ('onhashchange' in window) {
 <span id="L1359" class="LineNr">1359 </span>  init:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
 <span id="L1360" class="LineNr">1360 </span>  <span class="Comment"># while not at start of line, move</span>
 <span id="L1361" class="LineNr">1361 </span>  <span class="Delimiter">{</span>
-<span id="L1362" class="LineNr">1362 </span>    at-start-of-text?:bool <span class="Special">&lt;-</span> equal before-cursor, init
-<span id="L1363" class="LineNr">1363 </span>    <span class="muControl">break-if</span> at-start-of-text?
-<span id="L1364" class="LineNr">1364 </span>    <a href='../065duplex_list.mu.html#L36'>prev</a>:char <span class="Special">&lt;-</span> get *before-cursor, <span class="Constant">value:offset</span>
-<span id="L1365" class="LineNr">1365 </span>    at-start-of-line?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L36'>prev</a>, <span class="Constant">10/newline</span>
-<span id="L1366" class="LineNr">1366 </span>    <span class="muControl">break-if</span> at-start-of-line?
-<span id="L1367" class="LineNr">1367 </span>    before-cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> before-cursor
-<span id="L1368" class="LineNr">1368 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
-<span id="L1369" class="LineNr">1369 </span>    assert before-cursor, <span class="Constant">[move-to-start-of-line tried to move before start of text]</span>
-<span id="L1370" class="LineNr">1370 </span>    <span class="muControl">loop</span>
+<span id="L1362" class="LineNr">1362 </span>  <span class="Conceal">¦</span> at-start-of-text?:bool <span class="Special">&lt;-</span> equal before-cursor, init
+<span id="L1363" class="LineNr">1363 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-start-of-text?
+<span id="L1364" class="LineNr">1364 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a>:char <span class="Special">&lt;-</span> get *before-cursor, <span class="Constant">value:offset</span>
+<span id="L1365" class="LineNr">1365 </span>  <span class="Conceal">¦</span> at-start-of-line?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L36'>prev</a>, <span class="Constant">10/newline</span>
+<span id="L1366" class="LineNr">1366 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-start-of-line?
+<span id="L1367" class="LineNr">1367 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> before-cursor
+<span id="L1368" class="LineNr">1368 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
+<span id="L1369" class="LineNr">1369 </span>  <span class="Conceal">¦</span> assert before-cursor, <span class="Constant">[move-to-start-of-line tried to move before start of text]</span>
+<span id="L1370" class="LineNr">1370 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L1371" class="LineNr">1371 </span>  <span class="Delimiter">}</span>
 <span id="L1372" class="LineNr">1372 </span>]
 <span id="L1373" class="LineNr">1373 </span>
@@ -1441,18 +1442,18 @@ if ('onhashchange' in window) {
 <span id="L1381" class="LineNr">1381 </span>  $clear-trace
 <span id="L1382" class="LineNr">1382 </span>  <span class="Comment"># start on first line (no newline before), press ctrl-a</span>
 <span id="L1383" class="LineNr">1383 </span>  assume-console [
-<span id="L1384" class="LineNr">1384 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
-<span id="L1385" class="LineNr">1385 </span>    press ctrl-a
+<span id="L1384" class="LineNr">1384 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
+<span id="L1385" class="LineNr">1385 </span>  <span class="Conceal">¦</span> press ctrl-a
 <span id="L1386" class="LineNr">1386 </span>  ]
 <span id="L1387" class="LineNr">1387 </span>  run [
-<span id="L1388" class="LineNr">1388 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L1389" class="LineNr">1389 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L1390" class="LineNr">1390 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L1388" class="LineNr">1388 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1389" class="LineNr">1389 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L1390" class="LineNr">1390 </span>  <span class="Conceal">¦</span> 5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1391" class="LineNr">1391 </span>  ]
 <span id="L1392" class="LineNr">1392 </span>  <span class="Comment"># cursor moves to start of line</span>
 <span id="L1393" class="LineNr">1393 </span>  memory-should-contain [
-<span id="L1394" class="LineNr">1394 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1395" class="LineNr">1395 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
+<span id="L1394" class="LineNr">1394 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1395" class="LineNr">1395 </span>  <span class="Conceal">¦</span><span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
 <span id="L1396" class="LineNr">1396 </span>  ]
 <span id="L1397" class="LineNr">1397 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L1398" class="LineNr">1398 </span>]
@@ -1466,18 +1467,18 @@ if ('onhashchange' in window) {
 <span id="L1406" class="LineNr">1406 </span>  $clear-trace
 <span id="L1407" class="LineNr">1407 </span>  <span class="Comment"># start on second line, press 'home'</span>
 <span id="L1408" class="LineNr">1408 </span>  assume-console [
-<span id="L1409" class="LineNr">1409 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
-<span id="L1410" class="LineNr">1410 </span>    press home
+<span id="L1409" class="LineNr">1409 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
+<span id="L1410" class="LineNr">1410 </span>  <span class="Conceal">¦</span> press home
 <span id="L1411" class="LineNr">1411 </span>  ]
 <span id="L1412" class="LineNr">1412 </span>  run [
-<span id="L1413" class="LineNr">1413 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L1414" class="LineNr">1414 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L1415" class="LineNr">1415 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L1413" class="LineNr">1413 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
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 <span id="L1416" class="LineNr">1416 </span>  ]
 <span id="L1417" class="LineNr">1417 </span>  <span class="Comment"># cursor moves to start of line</span>
 <span id="L1418" class="LineNr">1418 </span>  memory-should-contain [
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-<span id="L1420" class="LineNr">1420 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
+<span id="L1419" class="LineNr">1419 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L1420" class="LineNr">1420 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
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 <span id="L1422" class="LineNr">1422 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L1423" class="LineNr">1423 </span>]
@@ -1492,18 +1493,18 @@ if ('onhashchange' in window) {
 <span id="L1432" class="LineNr">1432 </span>  $clear-trace
 <span id="L1433" class="LineNr">1433 </span>  <span class="Comment"># start on first line (no newline before), press 'home'</span>
 <span id="L1434" class="LineNr">1434 </span>  assume-console [
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-<span id="L1436" class="LineNr">1436 </span>    press home
+<span id="L1435" class="LineNr">1435 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
+<span id="L1436" class="LineNr">1436 </span>  <span class="Conceal">¦</span> press home
 <span id="L1437" class="LineNr">1437 </span>  ]
 <span id="L1438" class="LineNr">1438 </span>  run [
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-<span id="L1440" class="LineNr">1440 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L1441" class="LineNr">1441 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L1439" class="LineNr">1439 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
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+<span id="L1441" class="LineNr">1441 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
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 <span id="L1443" class="LineNr">1443 </span>  <span class="Comment"># cursor moves to start of line</span>
 <span id="L1444" class="LineNr">1444 </span>  memory-should-contain [
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-<span id="L1446" class="LineNr">1446 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
+<span id="L1445" class="LineNr">1445 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1446" class="LineNr">1446 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
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 <span id="L1448" class="LineNr">1448 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L1449" class="LineNr">1449 </span>]
@@ -1520,64 +1521,64 @@ if ('onhashchange' in window) {
 <span id="L1460" class="LineNr">1460 </span>  $clear-trace
 <span id="L1461" class="LineNr">1461 </span>  <span class="Comment"># start on first line, press ctrl-e</span>
 <span id="L1462" class="LineNr">1462 </span>  assume-console [
-<span id="L1463" class="LineNr">1463 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
-<span id="L1464" class="LineNr">1464 </span>    press ctrl-e
+<span id="L1463" class="LineNr">1463 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
+<span id="L1464" class="LineNr">1464 </span>  <span class="Conceal">¦</span> press ctrl-e
 <span id="L1465" class="LineNr">1465 </span>  ]
 <span id="L1466" class="LineNr">1466 </span>  run [
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-<span id="L1468" class="LineNr">1468 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L1469" class="LineNr">1469 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L1467" class="LineNr">1467 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1468" class="LineNr">1468 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L1469" class="LineNr">1469 </span>  <span class="Conceal">¦</span> 5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1470" class="LineNr">1470 </span>  ]
 <span id="L1471" class="LineNr">1471 </span>  <span class="Comment"># cursor moves to end of line</span>
 <span id="L1472" class="LineNr">1472 </span>  memory-should-contain [
-<span id="L1473" class="LineNr">1473 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1474" class="LineNr">1474 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L1473" class="LineNr">1473 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1474" class="LineNr">1474 </span>  <span class="Conceal">¦</span><span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
 <span id="L1475" class="LineNr">1475 </span>  ]
 <span id="L1476" class="LineNr">1476 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L1477" class="LineNr">1477 </span>  <span class="Comment"># editor inserts future characters at cursor</span>
 <span id="L1478" class="LineNr">1478 </span>  assume-console [
-<span id="L1479" class="LineNr">1479 </span>    type <span class="Constant">[z]</span>
+<span id="L1479" class="LineNr">1479 </span>  <span class="Conceal">¦</span> type <span class="Constant">[z]</span>
 <span id="L1480" class="LineNr">1480 </span>  ]
 <span id="L1481" class="LineNr">1481 </span>  run [
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-<span id="L1483" class="LineNr">1483 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L1484" class="LineNr">1484 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L1482" class="LineNr">1482 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1483" class="LineNr">1483 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L1484" class="LineNr">1484 </span>  <span class="Conceal">¦</span> 5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
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 <span id="L1486" class="LineNr">1486 </span>  memory-should-contain [
-<span id="L1487" class="LineNr">1487 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1488" class="LineNr">1488 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
+<span id="L1487" class="LineNr">1487 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1488" class="LineNr">1488 </span>  <span class="Conceal">¦</span><span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
 <span id="L1489" class="LineNr">1489 </span>  ]
 <span id="L1490" class="LineNr">1490 </span>  screen-should-contain [
-<span id="L1491" class="LineNr">1491 </span>   <span class="Constant"> .          .</span>
-<span id="L1492" class="LineNr">1492 </span>   <span class="Constant"> .123z      .</span>
-<span id="L1493" class="LineNr">1493 </span>   <span class="Constant"> .456       .</span>
-<span id="L1494" class="LineNr">1494 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1495" class="LineNr">1495 </span>   <span class="Constant"> .          .</span>
+<span id="L1491" class="LineNr">1491 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1492" class="LineNr">1492 </span>  <span class="Conceal">¦</span><span class="Constant"> .123z      .</span>
+<span id="L1493" class="LineNr">1493 </span>  <span class="Conceal">¦</span><span class="Constant"> .456       .</span>
+<span id="L1494" class="LineNr">1494 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1495" class="LineNr">1495 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1496" class="LineNr">1496 </span>  ]
 <span id="L1497" class="LineNr">1497 </span>  check-trace-count-for-label<span class="Constant"> 1</span>, <span class="Constant">[print-character]</span>
 <span id="L1498" class="LineNr">1498 </span>]
 <span id="L1499" class="LineNr">1499 </span>
 <span id="L1500" class="LineNr">1500 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L183'>&lt;handle-special-character&gt;</a></span> [
 <span id="L1501" class="LineNr">1501 </span>  <span class="Delimiter">{</span>
-<span id="L1502" class="LineNr">1502 </span>    move-to-end-of-line?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">5/ctrl-e</span>
-<span id="L1503" class="LineNr">1503 </span>    <span class="muControl">break-unless</span> move-to-end-of-line?
-<span id="L1504" class="LineNr">1504 </span><span class="Constant">    &lt;move-cursor-begin&gt;</span>
-<span id="L1505" class="LineNr">1505 </span>    <a href='003-shortcuts.mu.html#L1524'>move-to-end-of-line</a> editor
-<span id="L1506" class="LineNr">1506 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
-<span id="L1507" class="LineNr">1507 </span><span class="Constant">    &lt;move-cursor-end&gt;</span>
-<span id="L1508" class="LineNr">1508 </span>    <span class="muControl">return</span> <span class="Constant">0/don't-render</span>
+<span id="L1502" class="LineNr">1502 </span>  <span class="Conceal">¦</span> move-to-end-of-line?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">5/ctrl-e</span>
+<span id="L1503" class="LineNr">1503 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> move-to-end-of-line?
+<span id="L1504" class="LineNr">1504 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-begin&gt;</span>
+<span id="L1505" class="LineNr">1505 </span>  <span class="Conceal">¦</span> <a href='003-shortcuts.mu.html#L1524'>move-to-end-of-line</a> editor
+<span id="L1506" class="LineNr">1506 </span>  <span class="Conceal">¦</span> undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
+<span id="L1507" class="LineNr">1507 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-end&gt;</span>
+<span id="L1508" class="LineNr">1508 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">0/don't-render</span>
 <span id="L1509" class="LineNr">1509 </span>  <span class="Delimiter">}</span>
 <span id="L1510" class="LineNr">1510 </span>]
 <span id="L1511" class="LineNr">1511 </span>
 <span id="L1512" class="LineNr">1512 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L197'>&lt;handle-special-key&gt;</a></span> [
 <span id="L1513" class="LineNr">1513 </span>  <span class="Delimiter">{</span>
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-<span id="L1515" class="LineNr">1515 </span>    <span class="muControl">break-unless</span> move-to-end-of-line?
-<span id="L1516" class="LineNr">1516 </span><span class="Constant">    &lt;move-cursor-begin&gt;</span>
-<span id="L1517" class="LineNr">1517 </span>    <a href='003-shortcuts.mu.html#L1524'>move-to-end-of-line</a> editor
-<span id="L1518" class="LineNr">1518 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
-<span id="L1519" class="LineNr">1519 </span><span class="Constant">    &lt;move-cursor-end&gt;</span>
-<span id="L1520" class="LineNr">1520 </span>    <span class="muControl">return</span> <span class="Constant">0/don't-render</span>
+<span id="L1514" class="LineNr">1514 </span>  <span class="Conceal">¦</span> move-to-end-of-line?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65520/end</span>
+<span id="L1515" class="LineNr">1515 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> move-to-end-of-line?
+<span id="L1516" class="LineNr">1516 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-begin&gt;</span>
+<span id="L1517" class="LineNr">1517 </span>  <span class="Conceal">¦</span> <a href='003-shortcuts.mu.html#L1524'>move-to-end-of-line</a> editor
+<span id="L1518" class="LineNr">1518 </span>  <span class="Conceal">¦</span> undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
+<span id="L1519" class="LineNr">1519 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-end&gt;</span>
+<span id="L1520" class="LineNr">1520 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">0/don't-render</span>
 <span id="L1521" class="LineNr">1521 </span>  <span class="Delimiter">}</span>
 <span id="L1522" class="LineNr">1522 </span>]
 <span id="L1523" class="LineNr">1523 </span>
@@ -1588,16 +1589,16 @@ if ('onhashchange' in window) {
 <span id="L1528" class="LineNr">1528 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
 <span id="L1529" class="LineNr">1529 </span>  <span class="Comment"># while not at start of line, move</span>
 <span id="L1530" class="LineNr">1530 </span>  <span class="Delimiter">{</span>
-<span id="L1531" class="LineNr">1531 </span>    <a href='../065duplex_list.mu.html#L29'>next</a>:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
-<span id="L1532" class="LineNr">1532 </span>    <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L29'>next</a>  <span class="Comment"># end of text</span>
-<span id="L1533" class="LineNr">1533 </span>    nextc:char <span class="Special">&lt;-</span> get *next, <span class="Constant">value:offset</span>
-<span id="L1534" class="LineNr">1534 </span>    at-end-of-line?:bool <span class="Special">&lt;-</span> equal nextc, <span class="Constant">10/newline</span>
-<span id="L1535" class="LineNr">1535 </span>    <span class="muControl">break-if</span> at-end-of-line?
-<span id="L1536" class="LineNr">1536 </span>    before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L29'>next</a>
-<span id="L1537" class="LineNr">1537 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
-<span id="L1538" class="LineNr">1538 </span>    cursor-column <span class="Special">&lt;-</span> add cursor-column,<span class="Constant"> 1</span>
-<span id="L1539" class="LineNr">1539 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
-<span id="L1540" class="LineNr">1540 </span>    <span class="muControl">loop</span>
+<span id="L1531" class="LineNr">1531 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L29'>next</a>:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L1532" class="LineNr">1532 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L29'>next</a>  <span class="Comment"># end of text</span>
+<span id="L1533" class="LineNr">1533 </span>  <span class="Conceal">¦</span> nextc:char <span class="Special">&lt;-</span> get *next, <span class="Constant">value:offset</span>
+<span id="L1534" class="LineNr">1534 </span>  <span class="Conceal">¦</span> at-end-of-line?:bool <span class="Special">&lt;-</span> equal nextc, <span class="Constant">10/newline</span>
+<span id="L1535" class="LineNr">1535 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-end-of-line?
+<span id="L1536" class="LineNr">1536 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L29'>next</a>
+<span id="L1537" class="LineNr">1537 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
+<span id="L1538" class="LineNr">1538 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> add cursor-column,<span class="Constant"> 1</span>
+<span id="L1539" class="LineNr">1539 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
+<span id="L1540" class="LineNr">1540 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L1541" class="LineNr">1541 </span>  <span class="Delimiter">}</span>
 <span id="L1542" class="LineNr">1542 </span>]
 <span id="L1543" class="LineNr">1543 </span>
@@ -1611,18 +1612,18 @@ if ('onhashchange' in window) {
 <span id="L1551" class="LineNr">1551 </span>  $clear-trace
 <span id="L1552" class="LineNr">1552 </span>  <span class="Comment"># start on second line (no newline after), press ctrl-e</span>
 <span id="L1553" class="LineNr">1553 </span>  assume-console [
-<span id="L1554" class="LineNr">1554 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
-<span id="L1555" class="LineNr">1555 </span>    press ctrl-e
+<span id="L1554" class="LineNr">1554 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
+<span id="L1555" class="LineNr">1555 </span>  <span class="Conceal">¦</span> press ctrl-e
 <span id="L1556" class="LineNr">1556 </span>  ]
 <span id="L1557" class="LineNr">1557 </span>  run [
-<span id="L1558" class="LineNr">1558 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L1559" class="LineNr">1559 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L1560" class="LineNr">1560 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L1558" class="LineNr">1558 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1559" class="LineNr">1559 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L1560" class="LineNr">1560 </span>  <span class="Conceal">¦</span> 5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1561" class="LineNr">1561 </span>  ]
 <span id="L1562" class="LineNr">1562 </span>  <span class="Comment"># cursor moves to end of line</span>
 <span id="L1563" class="LineNr">1563 </span>  memory-should-contain [
-<span id="L1564" class="LineNr">1564 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
-<span id="L1565" class="LineNr">1565 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L1564" class="LineNr">1564 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L1565" class="LineNr">1565 </span>  <span class="Conceal">¦</span><span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
 <span id="L1566" class="LineNr">1566 </span>  ]
 <span id="L1567" class="LineNr">1567 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L1568" class="LineNr">1568 </span>]
@@ -1637,18 +1638,18 @@ if ('onhashchange' in window) {
 <span id="L1577" class="LineNr">1577 </span>  $clear-trace
 <span id="L1578" class="LineNr">1578 </span>  <span class="Comment"># start on first line, press 'end'</span>
 <span id="L1579" class="LineNr">1579 </span>  assume-console [
-<span id="L1580" class="LineNr">1580 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
-<span id="L1581" class="LineNr">1581 </span>    press end
+<span id="L1580" class="LineNr">1580 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
+<span id="L1581" class="LineNr">1581 </span>  <span class="Conceal">¦</span> press end
 <span id="L1582" class="LineNr">1582 </span>  ]
 <span id="L1583" class="LineNr">1583 </span>  run [
-<span id="L1584" class="LineNr">1584 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L1585" class="LineNr">1585 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L1586" class="LineNr">1586 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L1584" class="LineNr">1584 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1585" class="LineNr">1585 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L1586" class="LineNr">1586 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1587" class="LineNr">1587 </span>  ]
 <span id="L1588" class="LineNr">1588 </span>  <span class="Comment"># cursor moves to end of line</span>
 <span id="L1589" class="LineNr">1589 </span>  memory-should-contain [
-<span id="L1590" class="LineNr">1590 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1591" class="LineNr">1591 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L1590" class="LineNr">1590 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1591" class="LineNr">1591 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
 <span id="L1592" class="LineNr">1592 </span>  ]
 <span id="L1593" class="LineNr">1593 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L1594" class="LineNr">1594 </span>]
@@ -1663,18 +1664,18 @@ if ('onhashchange' in window) {
 <span id="L1603" class="LineNr">1603 </span>  $clear-trace
 <span id="L1604" class="LineNr">1604 </span>  <span class="Comment"># start on second line (no newline after), press 'end'</span>
 <span id="L1605" class="LineNr">1605 </span>  assume-console [
-<span id="L1606" class="LineNr">1606 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
-<span id="L1607" class="LineNr">1607 </span>    press end
+<span id="L1606" class="LineNr">1606 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
+<span id="L1607" class="LineNr">1607 </span>  <span class="Conceal">¦</span> press end
 <span id="L1608" class="LineNr">1608 </span>  ]
 <span id="L1609" class="LineNr">1609 </span>  run [
-<span id="L1610" class="LineNr">1610 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L1611" class="LineNr">1611 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L1612" class="LineNr">1612 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L1610" class="LineNr">1610 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1611" class="LineNr">1611 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L1612" class="LineNr">1612 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1613" class="LineNr">1613 </span>  ]
 <span id="L1614" class="LineNr">1614 </span>  <span class="Comment"># cursor moves to end of line</span>
 <span id="L1615" class="LineNr">1615 </span>  memory-should-contain [
-<span id="L1616" class="LineNr">1616 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
-<span id="L1617" class="LineNr">1617 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L1616" class="LineNr">1616 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L1617" class="LineNr">1617 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
 <span id="L1618" class="LineNr">1618 </span>  ]
 <span id="L1619" class="LineNr">1619 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L1620" class="LineNr">1620 </span>]
@@ -1689,30 +1690,30 @@ if ('onhashchange' in window) {
 <span id="L1629" class="LineNr">1629 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L1630" class="LineNr">1630 </span>  <span class="Comment"># start on second line, press ctrl-u</span>
 <span id="L1631" class="LineNr">1631 </span>  assume-console [
-<span id="L1632" class="LineNr">1632 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 2</span>
-<span id="L1633" class="LineNr">1633 </span>    press ctrl-u
+<span id="L1632" class="LineNr">1632 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 2</span>
+<span id="L1633" class="LineNr">1633 </span>  <span class="Conceal">¦</span> press ctrl-u
 <span id="L1634" class="LineNr">1634 </span>  ]
 <span id="L1635" class="LineNr">1635 </span>  run [
-<span id="L1636" class="LineNr">1636 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1636" class="LineNr">1636 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1637" class="LineNr">1637 </span>  ]
 <span id="L1638" class="LineNr">1638 </span>  <span class="Comment"># cursor deletes to start of line</span>
 <span id="L1639" class="LineNr">1639 </span>  screen-should-contain [
-<span id="L1640" class="LineNr">1640 </span>   <span class="Constant"> .          .</span>
-<span id="L1641" class="LineNr">1641 </span>   <span class="Constant"> .123       .</span>
-<span id="L1642" class="LineNr">1642 </span>   <span class="Constant"> .6         .</span>
-<span id="L1643" class="LineNr">1643 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1644" class="LineNr">1644 </span>   <span class="Constant"> .          .</span>
+<span id="L1640" class="LineNr">1640 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1641" class="LineNr">1641 </span>  <span class="Conceal">¦</span><span class="Constant"> .123       .</span>
+<span id="L1642" class="LineNr">1642 </span>  <span class="Conceal">¦</span><span class="Constant"> .6         .</span>
+<span id="L1643" class="LineNr">1643 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1644" class="LineNr">1644 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1645" class="LineNr">1645 </span>  ]
 <span id="L1646" class="LineNr">1646 </span>]
 <span id="L1647" class="LineNr">1647 </span>
 <span id="L1648" class="LineNr">1648 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L183'>&lt;handle-special-character&gt;</a></span> [
 <span id="L1649" class="LineNr">1649 </span>  <span class="Delimiter">{</span>
-<span id="L1650" class="LineNr">1650 </span>    delete-to-start-of-line?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">21/ctrl-u</span>
-<span id="L1651" class="LineNr">1651 </span>    <span class="muControl">break-unless</span> delete-to-start-of-line?
-<span id="L1652" class="LineNr">1652 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L1652'>&lt;delete-to-start-of-line-begin&gt;</a></span>
-<span id="L1653" class="LineNr">1653 </span>    deleted-cells:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1659'>delete-to-start-of-line</a> editor
-<span id="L1654" class="LineNr">1654 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L1654'>&lt;delete-to-start-of-line-end&gt;</a></span>
-<span id="L1655" class="LineNr">1655 </span>    <span class="muControl">return</span> <span class="Constant">1/go-render</span>
+<span id="L1650" class="LineNr">1650 </span>  <span class="Conceal">¦</span> delete-to-start-of-line?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">21/ctrl-u</span>
+<span id="L1651" class="LineNr">1651 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> delete-to-start-of-line?
+<span id="L1652" class="LineNr">1652 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> <a href='003-shortcuts.mu.html#L1652'>&lt;delete-to-start-of-line-begin&gt;</a></span>
+<span id="L1653" class="LineNr">1653 </span>  <span class="Conceal">¦</span> deleted-cells:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1659'>delete-to-start-of-line</a> editor
+<span id="L1654" class="LineNr">1654 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> <a href='003-shortcuts.mu.html#L1654'>&lt;delete-to-start-of-line-end&gt;</a></span>
+<span id="L1655" class="LineNr">1655 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">1/go-render</span>
 <span id="L1656" class="LineNr">1656 </span>  <span class="Delimiter">}</span>
 <span id="L1657" class="LineNr">1657 </span>]
 <span id="L1658" class="LineNr">1658 </span>
@@ -1725,14 +1726,14 @@ if ('onhashchange' in window) {
 <span id="L1665" class="LineNr">1665 </span>  start:&amp;:duplex-list:char <span class="Special">&lt;-</span> copy before-cursor
 <span id="L1666" class="LineNr">1666 </span>  end:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
 <span id="L1667" class="LineNr">1667 </span>  <span class="Delimiter">{</span>
-<span id="L1668" class="LineNr">1668 </span>    at-start-of-text?:bool <span class="Special">&lt;-</span> equal start, init
-<span id="L1669" class="LineNr">1669 </span>    <span class="muControl">break-if</span> at-start-of-text?
-<span id="L1670" class="LineNr">1670 </span>    curr:char <span class="Special">&lt;-</span> get *start, <span class="Constant">value:offset</span>
-<span id="L1671" class="LineNr">1671 </span>    at-start-of-line?:bool <span class="Special">&lt;-</span> equal curr, <span class="Constant">10/newline</span>
-<span id="L1672" class="LineNr">1672 </span>    <span class="muControl">break-if</span> at-start-of-line?
-<span id="L1673" class="LineNr">1673 </span>    start <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> start
-<span id="L1674" class="LineNr">1674 </span>    assert start, <span class="Constant">[delete-to-start-of-line tried to move before start of text]</span>
-<span id="L1675" class="LineNr">1675 </span>    <span class="muControl">loop</span>
+<span id="L1668" class="LineNr">1668 </span>  <span class="Conceal">¦</span> at-start-of-text?:bool <span class="Special">&lt;-</span> equal start, init
+<span id="L1669" class="LineNr">1669 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-start-of-text?
+<span id="L1670" class="LineNr">1670 </span>  <span class="Conceal">¦</span> curr:char <span class="Special">&lt;-</span> get *start, <span class="Constant">value:offset</span>
+<span id="L1671" class="LineNr">1671 </span>  <span class="Conceal">¦</span> at-start-of-line?:bool <span class="Special">&lt;-</span> equal curr, <span class="Constant">10/newline</span>
+<span id="L1672" class="LineNr">1672 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-start-of-line?
+<span id="L1673" class="LineNr">1673 </span>  <span class="Conceal">¦</span> start <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> start
+<span id="L1674" class="LineNr">1674 </span>  <span class="Conceal">¦</span> assert start, <span class="Constant">[delete-to-start-of-line tried to move before start of text]</span>
+<span id="L1675" class="LineNr">1675 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L1676" class="LineNr">1676 </span>  <span class="Delimiter">}</span>
 <span id="L1677" class="LineNr">1677 </span>  <span class="Comment"># snip it out</span>
 <span id="L1678" class="LineNr">1678 </span>  result:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> start
@@ -1752,19 +1753,19 @@ if ('onhashchange' in window) {
 <span id="L1692" class="LineNr">1692 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L1693" class="LineNr">1693 </span>  <span class="Comment"># start on first line (no newline before), press ctrl-u</span>
 <span id="L1694" class="LineNr">1694 </span>  assume-console [
-<span id="L1695" class="LineNr">1695 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 2</span>
-<span id="L1696" class="LineNr">1696 </span>    press ctrl-u
+<span id="L1695" class="LineNr">1695 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 2</span>
+<span id="L1696" class="LineNr">1696 </span>  <span class="Conceal">¦</span> press ctrl-u
 <span id="L1697" class="LineNr">1697 </span>  ]
 <span id="L1698" class="LineNr">1698 </span>  run [
-<span id="L1699" class="LineNr">1699 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1699" class="LineNr">1699 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1700" class="LineNr">1700 </span>  ]
 <span id="L1701" class="LineNr">1701 </span>  <span class="Comment"># cursor deletes to start of line</span>
 <span id="L1702" class="LineNr">1702 </span>  screen-should-contain [
-<span id="L1703" class="LineNr">1703 </span>   <span class="Constant"> .          .</span>
-<span id="L1704" class="LineNr">1704 </span>   <span class="Constant"> .3         .</span>
-<span id="L1705" class="LineNr">1705 </span>   <span class="Constant"> .456       .</span>
-<span id="L1706" class="LineNr">1706 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1707" class="LineNr">1707 </span>   <span class="Constant"> .          .</span>
+<span id="L1703" class="LineNr">1703 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1704" class="LineNr">1704 </span>  <span class="Conceal">¦</span><span class="Constant"> .3         .</span>
+<span id="L1705" class="LineNr">1705 </span>  <span class="Conceal">¦</span><span class="Constant"> .456       .</span>
+<span id="L1706" class="LineNr">1706 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1707" class="LineNr">1707 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1708" class="LineNr">1708 </span>  ]
 <span id="L1709" class="LineNr">1709 </span>]
 <span id="L1710" class="LineNr">1710 </span>
@@ -1776,19 +1777,19 @@ if ('onhashchange' in window) {
 <span id="L1716" class="LineNr">1716 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L1717" class="LineNr">1717 </span>  <span class="Comment"># start past end of line, press ctrl-u</span>
 <span id="L1718" class="LineNr">1718 </span>  assume-console [
-<span id="L1719" class="LineNr">1719 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
-<span id="L1720" class="LineNr">1720 </span>    press ctrl-u
+<span id="L1719" class="LineNr">1719 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
+<span id="L1720" class="LineNr">1720 </span>  <span class="Conceal">¦</span> press ctrl-u
 <span id="L1721" class="LineNr">1721 </span>  ]
 <span id="L1722" class="LineNr">1722 </span>  run [
-<span id="L1723" class="LineNr">1723 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1723" class="LineNr">1723 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1724" class="LineNr">1724 </span>  ]
 <span id="L1725" class="LineNr">1725 </span>  <span class="Comment"># cursor deletes to start of line</span>
 <span id="L1726" class="LineNr">1726 </span>  screen-should-contain [
-<span id="L1727" class="LineNr">1727 </span>   <span class="Constant"> .          .</span>
-<span id="L1728" class="LineNr">1728 </span>   <span class="Constant"> .          .</span>
-<span id="L1729" class="LineNr">1729 </span>   <span class="Constant"> .456       .</span>
-<span id="L1730" class="LineNr">1730 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1731" class="LineNr">1731 </span>   <span class="Constant"> .          .</span>
+<span id="L1727" class="LineNr">1727 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1728" class="LineNr">1728 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1729" class="LineNr">1729 </span>  <span class="Conceal">¦</span><span class="Constant"> .456       .</span>
+<span id="L1730" class="LineNr">1730 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1731" class="LineNr">1731 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1732" class="LineNr">1732 </span>  ]
 <span id="L1733" class="LineNr">1733 </span>]
 <span id="L1734" class="LineNr">1734 </span>
@@ -1800,19 +1801,19 @@ if ('onhashchange' in window) {
 <span id="L1740" class="LineNr">1740 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L1741" class="LineNr">1741 </span>  <span class="Comment"># start past end of final line, press ctrl-u</span>
 <span id="L1742" class="LineNr">1742 </span>  assume-console [
-<span id="L1743" class="LineNr">1743 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
-<span id="L1744" class="LineNr">1744 </span>    press ctrl-u
+<span id="L1743" class="LineNr">1743 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
+<span id="L1744" class="LineNr">1744 </span>  <span class="Conceal">¦</span> press ctrl-u
 <span id="L1745" class="LineNr">1745 </span>  ]
 <span id="L1746" class="LineNr">1746 </span>  run [
-<span id="L1747" class="LineNr">1747 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1747" class="LineNr">1747 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1748" class="LineNr">1748 </span>  ]
 <span id="L1749" class="LineNr">1749 </span>  <span class="Comment"># cursor deletes to start of line</span>
 <span id="L1750" class="LineNr">1750 </span>  screen-should-contain [
-<span id="L1751" class="LineNr">1751 </span>   <span class="Constant"> .          .</span>
-<span id="L1752" class="LineNr">1752 </span>   <span class="Constant"> .123       .</span>
-<span id="L1753" class="LineNr">1753 </span>   <span class="Constant"> .          .</span>
-<span id="L1754" class="LineNr">1754 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1755" class="LineNr">1755 </span>   <span class="Constant"> .          .</span>
+<span id="L1751" class="LineNr">1751 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1752" class="LineNr">1752 </span>  <span class="Conceal">¦</span><span class="Constant"> .123       .</span>
+<span id="L1753" class="LineNr">1753 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1754" class="LineNr">1754 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1755" class="LineNr">1755 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1756" class="LineNr">1756 </span>  ]
 <span id="L1757" class="LineNr">1757 </span>]
 <span id="L1758" class="LineNr">1758 </span>
@@ -1826,30 +1827,30 @@ if ('onhashchange' in window) {
 <span id="L1766" class="LineNr">1766 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L1767" class="LineNr">1767 </span>  <span class="Comment"># start on first line, press ctrl-k</span>
 <span id="L1768" class="LineNr">1768 </span>  assume-console [
-<span id="L1769" class="LineNr">1769 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
-<span id="L1770" class="LineNr">1770 </span>    press ctrl-k
+<span id="L1769" class="LineNr">1769 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
+<span id="L1770" class="LineNr">1770 </span>  <span class="Conceal">¦</span> press ctrl-k
 <span id="L1771" class="LineNr">1771 </span>  ]
 <span id="L1772" class="LineNr">1772 </span>  run [
-<span id="L1773" class="LineNr">1773 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1773" class="LineNr">1773 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1774" class="LineNr">1774 </span>  ]
 <span id="L1775" class="LineNr">1775 </span>  <span class="Comment"># cursor deletes to end of line</span>
 <span id="L1776" class="LineNr">1776 </span>  screen-should-contain [
-<span id="L1777" class="LineNr">1777 </span>   <span class="Constant"> .          .</span>
-<span id="L1778" class="LineNr">1778 </span>   <span class="Constant"> .1         .</span>
-<span id="L1779" class="LineNr">1779 </span>   <span class="Constant"> .456       .</span>
-<span id="L1780" class="LineNr">1780 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1781" class="LineNr">1781 </span>   <span class="Constant"> .          .</span>
+<span id="L1777" class="LineNr">1777 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1778" class="LineNr">1778 </span>  <span class="Conceal">¦</span><span class="Constant"> .1         .</span>
+<span id="L1779" class="LineNr">1779 </span>  <span class="Conceal">¦</span><span class="Constant"> .456       .</span>
+<span id="L1780" class="LineNr">1780 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1781" class="LineNr">1781 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1782" class="LineNr">1782 </span>  ]
 <span id="L1783" class="LineNr">1783 </span>]
 <span id="L1784" class="LineNr">1784 </span>
 <span id="L1785" class="LineNr">1785 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L183'>&lt;handle-special-character&gt;</a></span> [
 <span id="L1786" class="LineNr">1786 </span>  <span class="Delimiter">{</span>
-<span id="L1787" class="LineNr">1787 </span>    delete-to-end-of-line?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">11/ctrl-k</span>
-<span id="L1788" class="LineNr">1788 </span>    <span class="muControl">break-unless</span> delete-to-end-of-line?
-<span id="L1789" class="LineNr">1789 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L1789'>&lt;delete-to-end-of-line-begin&gt;</a></span>
-<span id="L1790" class="LineNr">1790 </span>    deleted-cells:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1796'>delete-to-end-of-line</a> editor
-<span id="L1791" class="LineNr">1791 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L1791'>&lt;delete-to-end-of-line-end&gt;</a></span>
-<span id="L1792" class="LineNr">1792 </span>    <span class="muControl">return</span> <span class="Constant">1/go-render</span>
+<span id="L1787" class="LineNr">1787 </span>  <span class="Conceal">¦</span> delete-to-end-of-line?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">11/ctrl-k</span>
+<span id="L1788" class="LineNr">1788 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> delete-to-end-of-line?
+<span id="L1789" class="LineNr">1789 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> <a href='003-shortcuts.mu.html#L1789'>&lt;delete-to-end-of-line-begin&gt;</a></span>
+<span id="L1790" class="LineNr">1790 </span>  <span class="Conceal">¦</span> deleted-cells:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1796'>delete-to-end-of-line</a> editor
+<span id="L1791" class="LineNr">1791 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> <a href='003-shortcuts.mu.html#L1791'>&lt;delete-to-end-of-line-end&gt;</a></span>
+<span id="L1792" class="LineNr">1792 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">1/go-render</span>
 <span id="L1793" class="LineNr">1793 </span>  <span class="Delimiter">}</span>
 <span id="L1794" class="LineNr">1794 </span>]
 <span id="L1795" class="LineNr">1795 </span>
@@ -1860,13 +1861,13 @@ if ('onhashchange' in window) {
 <span id="L1800" class="LineNr">1800 </span>  start:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
 <span id="L1801" class="LineNr">1801 </span>  end:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> start
 <span id="L1802" class="LineNr">1802 </span>  <span class="Delimiter">{</span>
-<span id="L1803" class="LineNr">1803 </span>    at-end-of-text?:bool <span class="Special">&lt;-</span> equal end, <span class="Constant">0/null</span>
-<span id="L1804" class="LineNr">1804 </span>    <span class="muControl">break-if</span> at-end-of-text?
-<span id="L1805" class="LineNr">1805 </span>    curr:char <span class="Special">&lt;-</span> get *end, <span class="Constant">value:offset</span>
-<span id="L1806" class="LineNr">1806 </span>    at-end-of-line?:bool <span class="Special">&lt;-</span> equal curr, <span class="Constant">10/newline</span>
-<span id="L1807" class="LineNr">1807 </span>    <span class="muControl">break-if</span> at-end-of-line?
-<span id="L1808" class="LineNr">1808 </span>    end <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> end
-<span id="L1809" class="LineNr">1809 </span>    <span class="muControl">loop</span>
+<span id="L1803" class="LineNr">1803 </span>  <span class="Conceal">¦</span> at-end-of-text?:bool <span class="Special">&lt;-</span> equal end, <span class="Constant">0/null</span>
+<span id="L1804" class="LineNr">1804 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-end-of-text?
+<span id="L1805" class="LineNr">1805 </span>  <span class="Conceal">¦</span> curr:char <span class="Special">&lt;-</span> get *end, <span class="Constant">value:offset</span>
+<span id="L1806" class="LineNr">1806 </span>  <span class="Conceal">¦</span> at-end-of-line?:bool <span class="Special">&lt;-</span> equal curr, <span class="Constant">10/newline</span>
+<span id="L1807" class="LineNr">1807 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-end-of-line?
+<span id="L1808" class="LineNr">1808 </span>  <span class="Conceal">¦</span> end <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> end
+<span id="L1809" class="LineNr">1809 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L1810" class="LineNr">1810 </span>  <span class="Delimiter">}</span>
 <span id="L1811" class="LineNr">1811 </span>  <span class="Comment"># snip it out</span>
 <span id="L1812" class="LineNr">1812 </span>  result <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> start
@@ -1881,19 +1882,19 @@ if ('onhashchange' in window) {
 <span id="L1821" class="LineNr">1821 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L1822" class="LineNr">1822 </span>  <span class="Comment"># start on second line (no newline after), press ctrl-k</span>
 <span id="L1823" class="LineNr">1823 </span>  assume-console [
-<span id="L1824" class="LineNr">1824 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
-<span id="L1825" class="LineNr">1825 </span>    press ctrl-k
+<span id="L1824" class="LineNr">1824 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
+<span id="L1825" class="LineNr">1825 </span>  <span class="Conceal">¦</span> press ctrl-k
 <span id="L1826" class="LineNr">1826 </span>  ]
 <span id="L1827" class="LineNr">1827 </span>  run [
-<span id="L1828" class="LineNr">1828 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1828" class="LineNr">1828 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1829" class="LineNr">1829 </span>  ]
 <span id="L1830" class="LineNr">1830 </span>  <span class="Comment"># cursor deletes to end of line</span>
 <span id="L1831" class="LineNr">1831 </span>  screen-should-contain [
-<span id="L1832" class="LineNr">1832 </span>   <span class="Constant"> .          .</span>
-<span id="L1833" class="LineNr">1833 </span>   <span class="Constant"> .123       .</span>
-<span id="L1834" class="LineNr">1834 </span>   <span class="Constant"> .4         .</span>
-<span id="L1835" class="LineNr">1835 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1836" class="LineNr">1836 </span>   <span class="Constant"> .          .</span>
+<span id="L1832" class="LineNr">1832 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1833" class="LineNr">1833 </span>  <span class="Conceal">¦</span><span class="Constant"> .123       .</span>
+<span id="L1834" class="LineNr">1834 </span>  <span class="Conceal">¦</span><span class="Constant"> .4         .</span>
+<span id="L1835" class="LineNr">1835 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1836" class="LineNr">1836 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1837" class="LineNr">1837 </span>  ]
 <span id="L1838" class="LineNr">1838 </span>]
 <span id="L1839" class="LineNr">1839 </span>
@@ -1905,19 +1906,19 @@ if ('onhashchange' in window) {
 <span id="L1845" class="LineNr">1845 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L1846" class="LineNr">1846 </span>  <span class="Comment"># start at end of line</span>
 <span id="L1847" class="LineNr">1847 </span>  assume-console [
-<span id="L1848" class="LineNr">1848 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 2</span>
-<span id="L1849" class="LineNr">1849 </span>    press ctrl-k
+<span id="L1848" class="LineNr">1848 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 2</span>
+<span id="L1849" class="LineNr">1849 </span>  <span class="Conceal">¦</span> press ctrl-k
 <span id="L1850" class="LineNr">1850 </span>  ]
 <span id="L1851" class="LineNr">1851 </span>  run [
-<span id="L1852" class="LineNr">1852 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1852" class="LineNr">1852 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1853" class="LineNr">1853 </span>  ]
 <span id="L1854" class="LineNr">1854 </span>  <span class="Comment"># cursor deletes just last character</span>
 <span id="L1855" class="LineNr">1855 </span>  screen-should-contain [
-<span id="L1856" class="LineNr">1856 </span>   <span class="Constant"> .          .</span>
-<span id="L1857" class="LineNr">1857 </span>   <span class="Constant"> .12        .</span>
-<span id="L1858" class="LineNr">1858 </span>   <span class="Constant"> .456       .</span>
-<span id="L1859" class="LineNr">1859 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1860" class="LineNr">1860 </span>   <span class="Constant"> .          .</span>
+<span id="L1856" class="LineNr">1856 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1857" class="LineNr">1857 </span>  <span class="Conceal">¦</span><span class="Constant"> .12        .</span>
+<span id="L1858" class="LineNr">1858 </span>  <span class="Conceal">¦</span><span class="Constant"> .456       .</span>
+<span id="L1859" class="LineNr">1859 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1860" class="LineNr">1860 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1861" class="LineNr">1861 </span>  ]
 <span id="L1862" class="LineNr">1862 </span>]
 <span id="L1863" class="LineNr">1863 </span>
@@ -1929,19 +1930,19 @@ if ('onhashchange' in window) {
 <span id="L1869" class="LineNr">1869 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L1870" class="LineNr">1870 </span>  <span class="Comment"># start past end of line</span>
 <span id="L1871" class="LineNr">1871 </span>  assume-console [
-<span id="L1872" class="LineNr">1872 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
-<span id="L1873" class="LineNr">1873 </span>    press ctrl-k
+<span id="L1872" class="LineNr">1872 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
+<span id="L1873" class="LineNr">1873 </span>  <span class="Conceal">¦</span> press ctrl-k
 <span id="L1874" class="LineNr">1874 </span>  ]
 <span id="L1875" class="LineNr">1875 </span>  run [
-<span id="L1876" class="LineNr">1876 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1876" class="LineNr">1876 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1877" class="LineNr">1877 </span>  ]
 <span id="L1878" class="LineNr">1878 </span>  <span class="Comment"># cursor deletes nothing</span>
 <span id="L1879" class="LineNr">1879 </span>  screen-should-contain [
-<span id="L1880" class="LineNr">1880 </span>   <span class="Constant"> .          .</span>
-<span id="L1881" class="LineNr">1881 </span>   <span class="Constant"> .123       .</span>
-<span id="L1882" class="LineNr">1882 </span>   <span class="Constant"> .456       .</span>
-<span id="L1883" class="LineNr">1883 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1884" class="LineNr">1884 </span>   <span class="Constant"> .          .</span>
+<span id="L1880" class="LineNr">1880 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1881" class="LineNr">1881 </span>  <span class="Conceal">¦</span><span class="Constant"> .123       .</span>
+<span id="L1882" class="LineNr">1882 </span>  <span class="Conceal">¦</span><span class="Constant"> .456       .</span>
+<span id="L1883" class="LineNr">1883 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1884" class="LineNr">1884 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1885" class="LineNr">1885 </span>  ]
 <span id="L1886" class="LineNr">1886 </span>]
 <span id="L1887" class="LineNr">1887 </span>
@@ -1953,19 +1954,19 @@ if ('onhashchange' in window) {
 <span id="L1893" class="LineNr">1893 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L1894" class="LineNr">1894 </span>  <span class="Comment"># start at end of text</span>
 <span id="L1895" class="LineNr">1895 </span>  assume-console [
-<span id="L1896" class="LineNr">1896 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 2</span>
-<span id="L1897" class="LineNr">1897 </span>    press ctrl-k
+<span id="L1896" class="LineNr">1896 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 2</span>
+<span id="L1897" class="LineNr">1897 </span>  <span class="Conceal">¦</span> press ctrl-k
 <span id="L1898" class="LineNr">1898 </span>  ]
 <span id="L1899" class="LineNr">1899 </span>  run [
-<span id="L1900" class="LineNr">1900 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1900" class="LineNr">1900 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1901" class="LineNr">1901 </span>  ]
 <span id="L1902" class="LineNr">1902 </span>  <span class="Comment"># cursor deletes just the final character</span>
 <span id="L1903" class="LineNr">1903 </span>  screen-should-contain [
-<span id="L1904" class="LineNr">1904 </span>   <span class="Constant"> .          .</span>
-<span id="L1905" class="LineNr">1905 </span>   <span class="Constant"> .123       .</span>
-<span id="L1906" class="LineNr">1906 </span>   <span class="Constant"> .45        .</span>
-<span id="L1907" class="LineNr">1907 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1908" class="LineNr">1908 </span>   <span class="Constant"> .          .</span>
+<span id="L1904" class="LineNr">1904 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1905" class="LineNr">1905 </span>  <span class="Conceal">¦</span><span class="Constant"> .123       .</span>
+<span id="L1906" class="LineNr">1906 </span>  <span class="Conceal">¦</span><span class="Constant"> .45        .</span>
+<span id="L1907" class="LineNr">1907 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1908" class="LineNr">1908 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1909" class="LineNr">1909 </span>  ]
 <span id="L1910" class="LineNr">1910 </span>]
 <span id="L1911" class="LineNr">1911 </span>
@@ -1977,19 +1978,19 @@ if ('onhashchange' in window) {
 <span id="L1917" class="LineNr">1917 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L1918" class="LineNr">1918 </span>  <span class="Comment"># start past end of text</span>
 <span id="L1919" class="LineNr">1919 </span>  assume-console [
-<span id="L1920" class="LineNr">1920 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
-<span id="L1921" class="LineNr">1921 </span>    press ctrl-k
+<span id="L1920" class="LineNr">1920 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
+<span id="L1921" class="LineNr">1921 </span>  <span class="Conceal">¦</span> press ctrl-k
 <span id="L1922" class="LineNr">1922 </span>  ]
 <span id="L1923" class="LineNr">1923 </span>  run [
-<span id="L1924" class="LineNr">1924 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1924" class="LineNr">1924 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1925" class="LineNr">1925 </span>  ]
 <span id="L1926" class="LineNr">1926 </span>  <span class="Comment"># cursor deletes nothing</span>
 <span id="L1927" class="LineNr">1927 </span>  screen-should-contain [
-<span id="L1928" class="LineNr">1928 </span>   <span class="Constant"> .          .</span>
-<span id="L1929" class="LineNr">1929 </span>   <span class="Constant"> .123       .</span>
-<span id="L1930" class="LineNr">1930 </span>   <span class="Constant"> .456       .</span>
-<span id="L1931" class="LineNr">1931 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1932" class="LineNr">1932 </span>   <span class="Constant"> .          .</span>
+<span id="L1928" class="LineNr">1928 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1929" class="LineNr">1929 </span>  <span class="Conceal">¦</span><span class="Constant"> .123       .</span>
+<span id="L1930" class="LineNr">1930 </span>  <span class="Conceal">¦</span><span class="Constant"> .456       .</span>
+<span id="L1931" class="LineNr">1931 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1932" class="LineNr">1932 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1933" class="LineNr">1933 </span>  ]
 <span id="L1934" class="LineNr">1934 </span>]
 <span id="L1935" class="LineNr">1935 </span>
@@ -2007,25 +2008,25 @@ if ('onhashchange' in window) {
 <span id="L1947" class="LineNr">1947 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L1948" class="LineNr">1948 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L1949" class="LineNr">1949 </span>  screen-should-contain [
-<span id="L1950" class="LineNr">1950 </span>   <span class="Constant"> .          .</span>
-<span id="L1951" class="LineNr">1951 </span>   <span class="Constant"> .a         .</span>
-<span id="L1952" class="LineNr">1952 </span>   <span class="Constant"> .b         .</span>
-<span id="L1953" class="LineNr">1953 </span>   <span class="Constant"> .c         .</span>
+<span id="L1950" class="LineNr">1950 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1951" class="LineNr">1951 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L1952" class="LineNr">1952 </span>  <span class="Conceal">¦</span><span class="Constant"> .b         .</span>
+<span id="L1953" class="LineNr">1953 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
 <span id="L1954" class="LineNr">1954 </span>  ]
 <span id="L1955" class="LineNr">1955 </span>  <span class="Comment"># position cursor at last line, then try to move further down</span>
 <span id="L1956" class="LineNr">1956 </span>  assume-console [
-<span id="L1957" class="LineNr">1957 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L1958" class="LineNr">1958 </span>    press down-arrow
+<span id="L1957" class="LineNr">1957 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L1958" class="LineNr">1958 </span>  <span class="Conceal">¦</span> press down-arrow
 <span id="L1959" class="LineNr">1959 </span>  ]
 <span id="L1960" class="LineNr">1960 </span>  run [
-<span id="L1961" class="LineNr">1961 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1961" class="LineNr">1961 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1962" class="LineNr">1962 </span>  ]
 <span id="L1963" class="LineNr">1963 </span>  <span class="Comment"># screen slides by one line</span>
 <span id="L1964" class="LineNr">1964 </span>  screen-should-contain [
-<span id="L1965" class="LineNr">1965 </span>   <span class="Constant"> .          .</span>
-<span id="L1966" class="LineNr">1966 </span>   <span class="Constant"> .b         .</span>
-<span id="L1967" class="LineNr">1967 </span>   <span class="Constant"> .c         .</span>
-<span id="L1968" class="LineNr">1968 </span>   <span class="Constant"> .d         .</span>
+<span id="L1965" class="LineNr">1965 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1966" class="LineNr">1966 </span>  <span class="Conceal">¦</span><span class="Constant"> .b         .</span>
+<span id="L1967" class="LineNr">1967 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
+<span id="L1968" class="LineNr">1968 </span>  <span class="Conceal">¦</span><span class="Constant"> .d         .</span>
 <span id="L1969" class="LineNr">1969 </span>  ]
 <span id="L1970" class="LineNr">1970 </span>]
 <span id="L1971" class="LineNr">1971 </span>
@@ -2052,22 +2053,22 @@ if ('onhashchange' in window) {
 <span id="L1992" class="LineNr">1992 </span>  curr:&amp;:duplex-list:char <span class="Special">&lt;-</span> copy original
 <span id="L1993" class="LineNr">1993 </span>  <span class="Comment"># skip the initial newline if it exists</span>
 <span id="L1994" class="LineNr">1994 </span>  <span class="Delimiter">{</span>
-<span id="L1995" class="LineNr">1995 </span>    c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
-<span id="L1996" class="LineNr">1996 </span>    at-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
-<span id="L1997" class="LineNr">1997 </span>    <span class="muControl">break-unless</span> at-newline?
-<span id="L1998" class="LineNr">1998 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
-<span id="L1999" class="LineNr">1999 </span>    count <span class="Special">&lt;-</span> add count,<span class="Constant"> 1</span>
+<span id="L1995" class="LineNr">1995 </span>  <span class="Conceal">¦</span> c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
+<span id="L1996" class="LineNr">1996 </span>  <span class="Conceal">¦</span> at-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
+<span id="L1997" class="LineNr">1997 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-newline?
+<span id="L1998" class="LineNr">1998 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L1999" class="LineNr">1999 </span>  <span class="Conceal">¦</span> count <span class="Special">&lt;-</span> add count,<span class="Constant"> 1</span>
 <span id="L2000" class="LineNr">2000 </span>  <span class="Delimiter">}</span>
 <span id="L2001" class="LineNr">2001 </span>  <span class="Delimiter">{</span>
-<span id="L2002" class="LineNr">2002 </span>    <span class="muControl">return-unless</span> curr, original
-<span id="L2003" class="LineNr">2003 </span>    done?:bool <span class="Special">&lt;-</span> greater-or-equal count, max
-<span id="L2004" class="LineNr">2004 </span>    <span class="muControl">break-if</span> done?
-<span id="L2005" class="LineNr">2005 </span>    c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
-<span id="L2006" class="LineNr">2006 </span>    at-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
-<span id="L2007" class="LineNr">2007 </span>    <span class="muControl">break-if</span> at-newline?
-<span id="L2008" class="LineNr">2008 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
-<span id="L2009" class="LineNr">2009 </span>    count <span class="Special">&lt;-</span> add count,<span class="Constant"> 1</span>
-<span id="L2010" class="LineNr">2010 </span>    <span class="muControl">loop</span>
+<span id="L2002" class="LineNr">2002 </span>  <span class="Conceal">¦</span> <span class="muControl">return-unless</span> curr, original
+<span id="L2003" class="LineNr">2003 </span>  <span class="Conceal">¦</span> done?:bool <span class="Special">&lt;-</span> greater-or-equal count, max
+<span id="L2004" class="LineNr">2004 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
+<span id="L2005" class="LineNr">2005 </span>  <span class="Conceal">¦</span> c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
+<span id="L2006" class="LineNr">2006 </span>  <span class="Conceal">¦</span> at-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
+<span id="L2007" class="LineNr">2007 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-newline?
+<span id="L2008" class="LineNr">2008 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L2009" class="LineNr">2009 </span>  <span class="Conceal">¦</span> count <span class="Special">&lt;-</span> add count,<span class="Constant"> 1</span>
+<span id="L2010" class="LineNr">2010 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L2011" class="LineNr">2011 </span>  <span class="Delimiter">}</span>
 <span id="L2012" class="LineNr">2012 </span>  <span class="muControl">return-unless</span> curr, original
 <span id="L2013" class="LineNr">2013 </span>  <span class="muControl">return</span> curr
@@ -2086,25 +2087,25 @@ if ('onhashchange' in window) {
 <span id="L2026" class="LineNr">2026 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
 <span id="L2027" class="LineNr">2027 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L2028" class="LineNr">2028 </span>  screen-should-contain [
-<span id="L2029" class="LineNr">2029 </span>   <span class="Constant"> .          .</span>
-<span id="L2030" class="LineNr">2030 </span>   <span class="Constant"> .abcd↩     .</span>
-<span id="L2031" class="LineNr">2031 </span>   <span class="Constant"> .ef        .</span>
-<span id="L2032" class="LineNr">2032 </span>   <span class="Constant"> .g         .</span>
+<span id="L2029" class="LineNr">2029 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2030" class="LineNr">2030 </span>  <span class="Conceal">¦</span><span class="Constant"> .abcd↩     .</span>
+<span id="L2031" class="LineNr">2031 </span>  <span class="Conceal">¦</span><span class="Constant"> .ef        .</span>
+<span id="L2032" class="LineNr">2032 </span>  <span class="Conceal">¦</span><span class="Constant"> .g         .</span>
 <span id="L2033" class="LineNr">2033 </span>  ]
 <span id="L2034" class="LineNr">2034 </span>  <span class="Comment"># position cursor at last line, then try to move further down</span>
 <span id="L2035" class="LineNr">2035 </span>  assume-console [
-<span id="L2036" class="LineNr">2036 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L2037" class="LineNr">2037 </span>    press down-arrow
+<span id="L2036" class="LineNr">2036 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L2037" class="LineNr">2037 </span>  <span class="Conceal">¦</span> press down-arrow
 <span id="L2038" class="LineNr">2038 </span>  ]
 <span id="L2039" class="LineNr">2039 </span>  run [
-<span id="L2040" class="LineNr">2040 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2040" class="LineNr">2040 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2041" class="LineNr">2041 </span>  ]
 <span id="L2042" class="LineNr">2042 </span>  <span class="Comment"># screen shows partial wrapped line</span>
 <span id="L2043" class="LineNr">2043 </span>  screen-should-contain [
-<span id="L2044" class="LineNr">2044 </span>   <span class="Constant"> .          .</span>
-<span id="L2045" class="LineNr">2045 </span>   <span class="Constant"> .ef        .</span>
-<span id="L2046" class="LineNr">2046 </span>   <span class="Constant"> .g         .</span>
-<span id="L2047" class="LineNr">2047 </span>   <span class="Constant"> .h         .</span>
+<span id="L2044" class="LineNr">2044 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2045" class="LineNr">2045 </span>  <span class="Conceal">¦</span><span class="Constant"> .ef        .</span>
+<span id="L2046" class="LineNr">2046 </span>  <span class="Conceal">¦</span><span class="Constant"> .g         .</span>
+<span id="L2047" class="LineNr">2047 </span>  <span class="Conceal">¦</span><span class="Constant"> .h         .</span>
 <span id="L2048" class="LineNr">2048 </span>  ]
 <span id="L2049" class="LineNr">2049 </span>]
 <span id="L2050" class="LineNr">2050 </span>
@@ -2120,32 +2121,32 @@ if ('onhashchange' in window) {
 <span id="L2060" class="LineNr">2060 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
 <span id="L2061" class="LineNr">2061 </span>  <span class="Comment"># position cursor at last line, then try to move further down</span>
 <span id="L2062" class="LineNr">2062 </span>  assume-console [
-<span id="L2063" class="LineNr">2063 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L2064" class="LineNr">2064 </span>    press down-arrow
+<span id="L2063" class="LineNr">2063 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L2064" class="LineNr">2064 </span>  <span class="Conceal">¦</span> press down-arrow
 <span id="L2065" class="LineNr">2065 </span>  ]
 <span id="L2066" class="LineNr">2066 </span>  run [
-<span id="L2067" class="LineNr">2067 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2067" class="LineNr">2067 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2068" class="LineNr">2068 </span>  ]
 <span id="L2069" class="LineNr">2069 </span>  <span class="Comment"># screen shows partial wrapped line containing a wrap icon</span>
 <span id="L2070" class="LineNr">2070 </span>  screen-should-contain [
-<span id="L2071" class="LineNr">2071 </span>   <span class="Constant"> .          .</span>
-<span id="L2072" class="LineNr">2072 </span>   <span class="Constant"> .efgh↩     .</span>
-<span id="L2073" class="LineNr">2073 </span>   <span class="Constant"> .ij        .</span>
-<span id="L2074" class="LineNr">2074 </span>   <span class="Constant"> .k         .</span>
+<span id="L2071" class="LineNr">2071 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2072" class="LineNr">2072 </span>  <span class="Conceal">¦</span><span class="Constant"> .efgh↩     .</span>
+<span id="L2073" class="LineNr">2073 </span>  <span class="Conceal">¦</span><span class="Constant"> .ij        .</span>
+<span id="L2074" class="LineNr">2074 </span>  <span class="Conceal">¦</span><span class="Constant"> .k         .</span>
 <span id="L2075" class="LineNr">2075 </span>  ]
 <span id="L2076" class="LineNr">2076 </span>  <span class="Comment"># scroll down again</span>
 <span id="L2077" class="LineNr">2077 </span>  assume-console [
-<span id="L2078" class="LineNr">2078 </span>    press down-arrow
+<span id="L2078" class="LineNr">2078 </span>  <span class="Conceal">¦</span> press down-arrow
 <span id="L2079" class="LineNr">2079 </span>  ]
 <span id="L2080" class="LineNr">2080 </span>  run [
-<span id="L2081" class="LineNr">2081 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2081" class="LineNr">2081 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2082" class="LineNr">2082 </span>  ]
 <span id="L2083" class="LineNr">2083 </span>  <span class="Comment"># screen shows partial wrapped line</span>
 <span id="L2084" class="LineNr">2084 </span>  screen-should-contain [
-<span id="L2085" class="LineNr">2085 </span>   <span class="Constant"> .          .</span>
-<span id="L2086" class="LineNr">2086 </span>   <span class="Constant"> .ij        .</span>
-<span id="L2087" class="LineNr">2087 </span>   <span class="Constant"> .k         .</span>
-<span id="L2088" class="LineNr">2088 </span>   <span class="Constant"> .l         .</span>
+<span id="L2085" class="LineNr">2085 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2086" class="LineNr">2086 </span>  <span class="Conceal">¦</span><span class="Constant"> .ij        .</span>
+<span id="L2087" class="LineNr">2087 </span>  <span class="Conceal">¦</span><span class="Constant"> .k         .</span>
+<span id="L2088" class="LineNr">2088 </span>  <span class="Conceal">¦</span><span class="Constant"> .l         .</span>
 <span id="L2089" class="LineNr">2089 </span>  ]
 <span id="L2090" class="LineNr">2090 </span>]
 <span id="L2091" class="LineNr">2091 </span>
@@ -2160,24 +2161,24 @@ if ('onhashchange' in window) {
 <span id="L2100" class="LineNr">2100 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
 <span id="L2101" class="LineNr">2101 </span>  <span class="Comment"># position cursor at end, type a character</span>
 <span id="L2102" class="LineNr">2102 </span>  assume-console [
-<span id="L2103" class="LineNr">2103 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 4</span>
-<span id="L2104" class="LineNr">2104 </span>    type <span class="Constant">[g]</span>
+<span id="L2103" class="LineNr">2103 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 4</span>
+<span id="L2104" class="LineNr">2104 </span>  <span class="Conceal">¦</span> type <span class="Constant">[g]</span>
 <span id="L2105" class="LineNr">2105 </span>  ]
 <span id="L2106" class="LineNr">2106 </span>  run [
-<span id="L2107" class="LineNr">2107 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L2108" class="LineNr">2108 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L2109" class="LineNr">2109 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L2107" class="LineNr">2107 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2108" class="LineNr">2108 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L2109" class="LineNr">2109 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L2110" class="LineNr">2110 </span>  ]
 <span id="L2111" class="LineNr">2111 </span>  <span class="Comment"># screen scrolls</span>
 <span id="L2112" class="LineNr">2112 </span>  screen-should-contain [
-<span id="L2113" class="LineNr">2113 </span>   <span class="Constant"> .     .</span>
-<span id="L2114" class="LineNr">2114 </span>   <span class="Constant"> .b    .</span>
-<span id="L2115" class="LineNr">2115 </span><span class="Constant">    .cdef↩.</span>
-<span id="L2116" class="LineNr">2116 </span>   <span class="Constant"> .g    .</span>
+<span id="L2113" class="LineNr">2113 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L2114" class="LineNr">2114 </span>  <span class="Conceal">¦</span><span class="Constant"> .b    .</span>
+<span id="L2115" class="LineNr">2115 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .cdef↩.</span>
+<span id="L2116" class="LineNr">2116 </span>  <span class="Conceal">¦</span><span class="Constant"> .g    .</span>
 <span id="L2117" class="LineNr">2117 </span>  ]
 <span id="L2118" class="LineNr">2118 </span>  memory-should-contain [
-<span id="L2119" class="LineNr">2119 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
-<span id="L2120" class="LineNr">2120 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L2119" class="LineNr">2119 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L2120" class="LineNr">2120 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L2121" class="LineNr">2121 </span>  ]
 <span id="L2122" class="LineNr">2122 </span>]
 <span id="L2123" class="LineNr">2123 </span>
@@ -2190,25 +2191,25 @@ if ('onhashchange' in window) {
 <span id="L2130" class="LineNr">2130 </span><span class="Constant">c]</span>
 <span id="L2131" class="LineNr">2131 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
 <span id="L2132" class="LineNr">2132 </span>  assume-console [
-<span id="L2133" class="LineNr">2133 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 4</span>
-<span id="L2134" class="LineNr">2134 </span>    type [
+<span id="L2133" class="LineNr">2133 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 4</span>
+<span id="L2134" class="LineNr">2134 </span>  <span class="Conceal">¦</span> type [
 <span id="L2135" class="LineNr">2135 </span>]
 <span id="L2136" class="LineNr">2136 </span>  ]
 <span id="L2137" class="LineNr">2137 </span>  run [
-<span id="L2138" class="LineNr">2138 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L2139" class="LineNr">2139 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L2140" class="LineNr">2140 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L2138" class="LineNr">2138 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2139" class="LineNr">2139 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L2140" class="LineNr">2140 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L2141" class="LineNr">2141 </span>  ]
 <span id="L2142" class="LineNr">2142 </span>  <span class="Comment"># screen scrolls</span>
 <span id="L2143" class="LineNr">2143 </span>  screen-should-contain [
-<span id="L2144" class="LineNr">2144 </span>   <span class="Constant"> .     .</span>
-<span id="L2145" class="LineNr">2145 </span>   <span class="Constant"> .b    .</span>
-<span id="L2146" class="LineNr">2146 </span>   <span class="Constant"> .c    .</span>
-<span id="L2147" class="LineNr">2147 </span>   <span class="Constant"> .     .</span>
+<span id="L2144" class="LineNr">2144 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L2145" class="LineNr">2145 </span>  <span class="Conceal">¦</span><span class="Constant"> .b    .</span>
+<span id="L2146" class="LineNr">2146 </span>  <span class="Conceal">¦</span><span class="Constant"> .c    .</span>
+<span id="L2147" class="LineNr">2147 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
 <span id="L2148" class="LineNr">2148 </span>  ]
 <span id="L2149" class="LineNr">2149 </span>  memory-should-contain [
-<span id="L2150" class="LineNr">2150 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
-<span id="L2151" class="LineNr">2151 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
+<span id="L2150" class="LineNr">2150 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L2151" class="LineNr">2151 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
 <span id="L2152" class="LineNr">2152 </span>  ]
 <span id="L2153" class="LineNr">2153 </span>]
 <span id="L2154" class="LineNr">2154 </span>
@@ -2223,24 +2224,24 @@ if ('onhashchange' in window) {
 <span id="L2163" class="LineNr">2163 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
 <span id="L2164" class="LineNr">2164 </span>  <span class="Comment"># position cursor at end of screen and try to move right</span>
 <span id="L2165" class="LineNr">2165 </span>  assume-console [
-<span id="L2166" class="LineNr">2166 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 3</span>
-<span id="L2167" class="LineNr">2167 </span>    press right-arrow
+<span id="L2166" class="LineNr">2166 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 3</span>
+<span id="L2167" class="LineNr">2167 </span>  <span class="Conceal">¦</span> press right-arrow
 <span id="L2168" class="LineNr">2168 </span>  ]
 <span id="L2169" class="LineNr">2169 </span>  run [
-<span id="L2170" class="LineNr">2170 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L2171" class="LineNr">2171 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L2172" class="LineNr">2172 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L2170" class="LineNr">2170 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2171" class="LineNr">2171 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L2172" class="LineNr">2172 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L2173" class="LineNr">2173 </span>  ]
 <span id="L2174" class="LineNr">2174 </span>  <span class="Comment"># screen scrolls</span>
 <span id="L2175" class="LineNr">2175 </span>  screen-should-contain [
-<span id="L2176" class="LineNr">2176 </span>   <span class="Constant"> .     .</span>
-<span id="L2177" class="LineNr">2177 </span>   <span class="Constant"> .b    .</span>
-<span id="L2178" class="LineNr">2178 </span><span class="Constant">    .cdef↩.</span>
-<span id="L2179" class="LineNr">2179 </span>   <span class="Constant"> .gh   .</span>
+<span id="L2176" class="LineNr">2176 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L2177" class="LineNr">2177 </span>  <span class="Conceal">¦</span><span class="Constant"> .b    .</span>
+<span id="L2178" class="LineNr">2178 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .cdef↩.</span>
+<span id="L2179" class="LineNr">2179 </span>  <span class="Conceal">¦</span><span class="Constant"> .gh   .</span>
 <span id="L2180" class="LineNr">2180 </span>  ]
 <span id="L2181" class="LineNr">2181 </span>  memory-should-contain [
-<span id="L2182" class="LineNr">2182 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
-<span id="L2183" class="LineNr">2183 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
+<span id="L2182" class="LineNr">2182 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L2183" class="LineNr">2183 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
 <span id="L2184" class="LineNr">2184 </span>  ]
 <span id="L2185" class="LineNr">2185 </span>]
 <span id="L2186" class="LineNr">2186 </span>
@@ -2256,24 +2257,24 @@ if ('onhashchange' in window) {
 <span id="L2196" class="LineNr">2196 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
 <span id="L2197" class="LineNr">2197 </span>  <span class="Comment"># position cursor at end of screen and try to move right</span>
 <span id="L2198" class="LineNr">2198 </span>  assume-console [
-<span id="L2199" class="LineNr">2199 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 3</span>
-<span id="L2200" class="LineNr">2200 </span>    press right-arrow
+<span id="L2199" class="LineNr">2199 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 3</span>
+<span id="L2200" class="LineNr">2200 </span>  <span class="Conceal">¦</span> press right-arrow
 <span id="L2201" class="LineNr">2201 </span>  ]
 <span id="L2202" class="LineNr">2202 </span>  run [
-<span id="L2203" class="LineNr">2203 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L2204" class="LineNr">2204 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L2205" class="LineNr">2205 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L2203" class="LineNr">2203 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2204" class="LineNr">2204 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L2205" class="LineNr">2205 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L2206" class="LineNr">2206 </span>  ]
 <span id="L2207" class="LineNr">2207 </span>  <span class="Comment"># screen scrolls</span>
 <span id="L2208" class="LineNr">2208 </span>  screen-should-contain [
-<span id="L2209" class="LineNr">2209 </span>   <span class="Constant"> .     .</span>
-<span id="L2210" class="LineNr">2210 </span>   <span class="Constant"> .b    .</span>
-<span id="L2211" class="LineNr">2211 </span>   <span class="Constant"> .c    .</span>
-<span id="L2212" class="LineNr">2212 </span>   <span class="Constant"> .d    .</span>
+<span id="L2209" class="LineNr">2209 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L2210" class="LineNr">2210 </span>  <span class="Conceal">¦</span><span class="Constant"> .b    .</span>
+<span id="L2211" class="LineNr">2211 </span>  <span class="Conceal">¦</span><span class="Constant"> .c    .</span>
+<span id="L2212" class="LineNr">2212 </span>  <span class="Conceal">¦</span><span class="Constant"> .d    .</span>
 <span id="L2213" class="LineNr">2213 </span>  ]
 <span id="L2214" class="LineNr">2214 </span>  memory-should-contain [
-<span id="L2215" class="LineNr">2215 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
-<span id="L2216" class="LineNr">2216 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
+<span id="L2215" class="LineNr">2215 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L2216" class="LineNr">2216 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
 <span id="L2217" class="LineNr">2217 </span>  ]
 <span id="L2218" class="LineNr">2218 </span>]
 <span id="L2219" class="LineNr">2219 </span>
@@ -2287,59 +2288,59 @@ if ('onhashchange' in window) {
 <span id="L2227" class="LineNr">2227 </span>  $clear-trace
 <span id="L2228" class="LineNr">2228 </span>  <span class="Comment"># try to move down past end of text</span>
 <span id="L2229" class="LineNr">2229 </span>  assume-console [
-<span id="L2230" class="LineNr">2230 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
-<span id="L2231" class="LineNr">2231 </span>    press down-arrow
+<span id="L2230" class="LineNr">2230 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
+<span id="L2231" class="LineNr">2231 </span>  <span class="Conceal">¦</span> press down-arrow
 <span id="L2232" class="LineNr">2232 </span>  ]
 <span id="L2233" class="LineNr">2233 </span>  run [
-<span id="L2234" class="LineNr">2234 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L2235" class="LineNr">2235 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L2236" class="LineNr">2236 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L2234" class="LineNr">2234 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2235" class="LineNr">2235 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L2236" class="LineNr">2236 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L2237" class="LineNr">2237 </span>  ]
 <span id="L2238" class="LineNr">2238 </span>  <span class="Comment"># screen should scroll, moving cursor to end of text</span>
 <span id="L2239" class="LineNr">2239 </span>  memory-should-contain [
-<span id="L2240" class="LineNr">2240 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L2241" class="LineNr">2241 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L2240" class="LineNr">2240 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L2241" class="LineNr">2241 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
 <span id="L2242" class="LineNr">2242 </span>  ]
 <span id="L2243" class="LineNr">2243 </span>  assume-console [
-<span id="L2244" class="LineNr">2244 </span>    type <span class="Constant">[0]</span>
+<span id="L2244" class="LineNr">2244 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
 <span id="L2245" class="LineNr">2245 </span>  ]
 <span id="L2246" class="LineNr">2246 </span>  run [
-<span id="L2247" class="LineNr">2247 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2247" class="LineNr">2247 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2248" class="LineNr">2248 </span>  ]
 <span id="L2249" class="LineNr">2249 </span>  screen-should-contain [
-<span id="L2250" class="LineNr">2250 </span>   <span class="Constant"> .          .</span>
-<span id="L2251" class="LineNr">2251 </span>   <span class="Constant"> .de0       .</span>
-<span id="L2252" class="LineNr">2252 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L2253" class="LineNr">2253 </span>   <span class="Constant"> .          .</span>
+<span id="L2250" class="LineNr">2250 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2251" class="LineNr">2251 </span>  <span class="Conceal">¦</span><span class="Constant"> .de0       .</span>
+<span id="L2252" class="LineNr">2252 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L2253" class="LineNr">2253 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L2254" class="LineNr">2254 </span>  ]
 <span id="L2255" class="LineNr">2255 </span>  <span class="Comment"># try to move down again</span>
 <span id="L2256" class="LineNr">2256 </span>  $clear-trace
 <span id="L2257" class="LineNr">2257 </span>  assume-console [
-<span id="L2258" class="LineNr">2258 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
-<span id="L2259" class="LineNr">2259 </span>    press down-arrow
+<span id="L2258" class="LineNr">2258 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
+<span id="L2259" class="LineNr">2259 </span>  <span class="Conceal">¦</span> press down-arrow
 <span id="L2260" class="LineNr">2260 </span>  ]
 <span id="L2261" class="LineNr">2261 </span>  run [
-<span id="L2262" class="LineNr">2262 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L2263" class="LineNr">2263 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L2264" class="LineNr">2264 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L2262" class="LineNr">2262 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2263" class="LineNr">2263 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L2264" class="LineNr">2264 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L2265" class="LineNr">2265 </span>  ]
 <span id="L2266" class="LineNr">2266 </span>  <span class="Comment"># screen stops scrolling because cursor is already at top</span>
 <span id="L2267" class="LineNr">2267 </span>  memory-should-contain [
-<span id="L2268" class="LineNr">2268 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L2269" class="LineNr">2269 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L2268" class="LineNr">2268 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L2269" class="LineNr">2269 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
 <span id="L2270" class="LineNr">2270 </span>  ]
 <span id="L2271" class="LineNr">2271 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
 <span id="L2272" class="LineNr">2272 </span>  assume-console [
-<span id="L2273" class="LineNr">2273 </span>    type <span class="Constant">[1]</span>
+<span id="L2273" class="LineNr">2273 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
 <span id="L2274" class="LineNr">2274 </span>  ]
 <span id="L2275" class="LineNr">2275 </span>  run [
-<span id="L2276" class="LineNr">2276 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2276" class="LineNr">2276 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2277" class="LineNr">2277 </span>  ]
 <span id="L2278" class="LineNr">2278 </span>  screen-should-contain [
-<span id="L2279" class="LineNr">2279 </span>   <span class="Constant"> .          .</span>
-<span id="L2280" class="LineNr">2280 </span>   <span class="Constant"> .de01      .</span>
-<span id="L2281" class="LineNr">2281 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L2282" class="LineNr">2282 </span>   <span class="Constant"> .          .</span>
+<span id="L2279" class="LineNr">2279 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2280" class="LineNr">2280 </span>  <span class="Conceal">¦</span><span class="Constant"> .de01      .</span>
+<span id="L2281" class="LineNr">2281 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L2282" class="LineNr">2282 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L2283" class="LineNr">2283 </span>  ]
 <span id="L2284" class="LineNr">2284 </span>]
 <span id="L2285" class="LineNr">2285 </span>
@@ -2359,19 +2360,19 @@ if ('onhashchange' in window) {
 <span id="L2299" class="LineNr">2299 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L2300" class="LineNr">2300 </span>  <span class="Comment"># scroll down one page and one line</span>
 <span id="L2301" class="LineNr">2301 </span>  assume-console [
-<span id="L2302" class="LineNr">2302 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
-<span id="L2303" class="LineNr">2303 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L2304" class="LineNr">2304 </span>    press down-arrow
+<span id="L2302" class="LineNr">2302 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L2303" class="LineNr">2303 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L2304" class="LineNr">2304 </span>  <span class="Conceal">¦</span> press down-arrow
 <span id="L2305" class="LineNr">2305 </span>  ]
 <span id="L2306" class="LineNr">2306 </span>  run [
-<span id="L2307" class="LineNr">2307 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2307" class="LineNr">2307 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2308" class="LineNr">2308 </span>  ]
 <span id="L2309" class="LineNr">2309 </span>  <span class="Comment"># screen scrolls down 3 lines</span>
 <span id="L2310" class="LineNr">2310 </span>  screen-should-contain [
-<span id="L2311" class="LineNr">2311 </span>   <span class="Constant"> .          .</span>
-<span id="L2312" class="LineNr">2312 </span>   <span class="Constant"> .d         .</span>
-<span id="L2313" class="LineNr">2313 </span>   <span class="Constant"> .e         .</span>
-<span id="L2314" class="LineNr">2314 </span>   <span class="Constant"> .f         .</span>
+<span id="L2311" class="LineNr">2311 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2312" class="LineNr">2312 </span>  <span class="Conceal">¦</span><span class="Constant"> .d         .</span>
+<span id="L2313" class="LineNr">2313 </span>  <span class="Conceal">¦</span><span class="Constant"> .e         .</span>
+<span id="L2314" class="LineNr">2314 </span>  <span class="Conceal">¦</span><span class="Constant"> .f         .</span>
 <span id="L2315" class="LineNr">2315 </span>  ]
 <span id="L2316" class="LineNr">2316 </span>]
 <span id="L2317" class="LineNr">2317 </span>
@@ -2389,25 +2390,25 @@ if ('onhashchange' in window) {
 <span id="L2329" class="LineNr">2329 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L2330" class="LineNr">2330 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L2331" class="LineNr">2331 </span>  screen-should-contain [
-<span id="L2332" class="LineNr">2332 </span>   <span class="Constant"> .          .</span>
-<span id="L2333" class="LineNr">2333 </span>   <span class="Constant"> .a         .</span>
-<span id="L2334" class="LineNr">2334 </span>   <span class="Constant"> .b         .</span>
-<span id="L2335" class="LineNr">2335 </span>   <span class="Constant"> .c         .</span>
+<span id="L2332" class="LineNr">2332 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2333" class="LineNr">2333 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L2334" class="LineNr">2334 </span>  <span class="Conceal">¦</span><span class="Constant"> .b         .</span>
+<span id="L2335" class="LineNr">2335 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
 <span id="L2336" class="LineNr">2336 </span>  ]
 <span id="L2337" class="LineNr">2337 </span>  <span class="Comment"># position cursor at top of second page, then try to move up</span>
 <span id="L2338" class="LineNr">2338 </span>  assume-console [
-<span id="L2339" class="LineNr">2339 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
-<span id="L2340" class="LineNr">2340 </span>    press up-arrow
+<span id="L2339" class="LineNr">2339 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L2340" class="LineNr">2340 </span>  <span class="Conceal">¦</span> press up-arrow
 <span id="L2341" class="LineNr">2341 </span>  ]
 <span id="L2342" class="LineNr">2342 </span>  run [
-<span id="L2343" class="LineNr">2343 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2343" class="LineNr">2343 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2344" class="LineNr">2344 </span>  ]
 <span id="L2345" class="LineNr">2345 </span>  <span class="Comment"># screen slides by one line</span>
 <span id="L2346" class="LineNr">2346 </span>  screen-should-contain [
-<span id="L2347" class="LineNr">2347 </span>   <span class="Constant"> .          .</span>
-<span id="L2348" class="LineNr">2348 </span>   <span class="Constant"> .b         .</span>
-<span id="L2349" class="LineNr">2349 </span>   <span class="Constant"> .c         .</span>
-<span id="L2350" class="LineNr">2350 </span>   <span class="Constant"> .d         .</span>
+<span id="L2347" class="LineNr">2347 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2348" class="LineNr">2348 </span>  <span class="Conceal">¦</span><span class="Constant"> .b         .</span>
+<span id="L2349" class="LineNr">2349 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
+<span id="L2350" class="LineNr">2350 </span>  <span class="Conceal">¦</span><span class="Constant"> .d         .</span>
 <span id="L2351" class="LineNr">2351 </span>  ]
 <span id="L2352" class="LineNr">2352 </span>]
 <span id="L2353" class="LineNr">2353 </span>
@@ -2438,29 +2439,29 @@ if ('onhashchange' in window) {
 <span id="L2378" class="LineNr">2378 </span>  sentinel:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
 <span id="L2379" class="LineNr">2379 </span>  len:num <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L193'>previous-line-length</a> curr, sentinel
 <span id="L2380" class="LineNr">2380 </span>  <span class="Delimiter">{</span>
-<span id="L2381" class="LineNr">2381 </span>    <span class="muControl">break-if</span> len
-<span id="L2382" class="LineNr">2382 </span>    <span class="Comment"># empty line; just skip this newline</span>
-<span id="L2383" class="LineNr">2383 </span>    <a href='../065duplex_list.mu.html#L36'>prev</a>:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> curr
-<span id="L2384" class="LineNr">2384 </span>    <span class="muControl">return-unless</span> <a href='../065duplex_list.mu.html#L36'>prev</a>, curr
-<span id="L2385" class="LineNr">2385 </span>    <span class="muControl">return</span> <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L2381" class="LineNr">2381 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> len
+<span id="L2382" class="LineNr">2382 </span>  <span class="Conceal">¦</span> <span class="Comment"># empty line; just skip this newline</span>
+<span id="L2383" class="LineNr">2383 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a>:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> curr
+<span id="L2384" class="LineNr">2384 </span>  <span class="Conceal">¦</span> <span class="muControl">return-unless</span> <a href='../065duplex_list.mu.html#L36'>prev</a>, curr
+<span id="L2385" class="LineNr">2385 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <a href='../065duplex_list.mu.html#L36'>prev</a>
 <span id="L2386" class="LineNr">2386 </span>  <span class="Delimiter">}</span>
 <span id="L2387" class="LineNr">2387 </span>  _, max:num <span class="Special">&lt;-</span> divide-with-remainder len, max-line-length
 <span id="L2388" class="LineNr">2388 </span>  <span class="Comment"># remainder 0 =&gt; scan one width-worth</span>
 <span id="L2389" class="LineNr">2389 </span>  <span class="Delimiter">{</span>
-<span id="L2390" class="LineNr">2390 </span>    <span class="muControl">break-if</span> max
-<span id="L2391" class="LineNr">2391 </span>    max <span class="Special">&lt;-</span> copy max-line-length
+<span id="L2390" class="LineNr">2390 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> max
+<span id="L2391" class="LineNr">2391 </span>  <span class="Conceal">¦</span> max <span class="Special">&lt;-</span> copy max-line-length
 <span id="L2392" class="LineNr">2392 </span>  <span class="Delimiter">}</span>
 <span id="L2393" class="LineNr">2393 </span>  max <span class="Special">&lt;-</span> add max,<span class="Constant"> 1</span>
 <span id="L2394" class="LineNr">2394 </span>  count:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
 <span id="L2395" class="LineNr">2395 </span>  <span class="Comment"># skip 'max' characters</span>
 <span id="L2396" class="LineNr">2396 </span>  <span class="Delimiter">{</span>
-<span id="L2397" class="LineNr">2397 </span>    done?:bool <span class="Special">&lt;-</span> greater-or-equal count, max
-<span id="L2398" class="LineNr">2398 </span>    <span class="muControl">break-if</span> done?
-<span id="L2399" class="LineNr">2399 </span>    <a href='../065duplex_list.mu.html#L36'>prev</a>:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> curr
-<span id="L2400" class="LineNr">2400 </span>    <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L36'>prev</a>
-<span id="L2401" class="LineNr">2401 </span>    curr <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
-<span id="L2402" class="LineNr">2402 </span>    count <span class="Special">&lt;-</span> add count,<span class="Constant"> 1</span>
-<span id="L2403" class="LineNr">2403 </span>    <span class="muControl">loop</span>
+<span id="L2397" class="LineNr">2397 </span>  <span class="Conceal">¦</span> done?:bool <span class="Special">&lt;-</span> greater-or-equal count, max
+<span id="L2398" class="LineNr">2398 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
+<span id="L2399" class="LineNr">2399 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a>:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> curr
+<span id="L2400" class="LineNr">2400 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L2401" class="LineNr">2401 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L2402" class="LineNr">2402 </span>  <span class="Conceal">¦</span> count <span class="Special">&lt;-</span> add count,<span class="Constant"> 1</span>
+<span id="L2403" class="LineNr">2403 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L2404" class="LineNr">2404 </span>  <span class="Delimiter">}</span>
 <span id="L2405" class="LineNr">2405 </span>  <span class="muControl">return</span> curr
 <span id="L2406" class="LineNr">2406 </span>]
@@ -2478,37 +2479,37 @@ if ('onhashchange' in window) {
 <span id="L2418" class="LineNr">2418 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
 <span id="L2419" class="LineNr">2419 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L2420" class="LineNr">2420 </span>  screen-should-contain [
-<span id="L2421" class="LineNr">2421 </span>   <span class="Constant"> .          .</span>
-<span id="L2422" class="LineNr">2422 </span>   <span class="Constant"> .abcd↩     .</span>
-<span id="L2423" class="LineNr">2423 </span>   <span class="Constant"> .ef        .</span>
-<span id="L2424" class="LineNr">2424 </span>   <span class="Constant"> .g         .</span>
+<span id="L2421" class="LineNr">2421 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2422" class="LineNr">2422 </span>  <span class="Conceal">¦</span><span class="Constant"> .abcd↩     .</span>
+<span id="L2423" class="LineNr">2423 </span>  <span class="Conceal">¦</span><span class="Constant"> .ef        .</span>
+<span id="L2424" class="LineNr">2424 </span>  <span class="Conceal">¦</span><span class="Constant"> .g         .</span>
 <span id="L2425" class="LineNr">2425 </span>  ]
 <span id="L2426" class="LineNr">2426 </span>  <span class="Comment"># position cursor at top of second page, just below wrapped line</span>
 <span id="L2427" class="LineNr">2427 </span>  assume-console [
-<span id="L2428" class="LineNr">2428 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L2428" class="LineNr">2428 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L2429" class="LineNr">2429 </span>  ]
 <span id="L2430" class="LineNr">2430 </span>  run [
-<span id="L2431" class="LineNr">2431 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2431" class="LineNr">2431 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2432" class="LineNr">2432 </span>  ]
 <span id="L2433" class="LineNr">2433 </span>  screen-should-contain [
-<span id="L2434" class="LineNr">2434 </span>   <span class="Constant"> .          .</span>
-<span id="L2435" class="LineNr">2435 </span>   <span class="Constant"> .g         .</span>
-<span id="L2436" class="LineNr">2436 </span>   <span class="Constant"> .h         .</span>
-<span id="L2437" class="LineNr">2437 </span>   <span class="Constant"> .i         .</span>
+<span id="L2434" class="LineNr">2434 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2435" class="LineNr">2435 </span>  <span class="Conceal">¦</span><span class="Constant"> .g         .</span>
+<span id="L2436" class="LineNr">2436 </span>  <span class="Conceal">¦</span><span class="Constant"> .h         .</span>
+<span id="L2437" class="LineNr">2437 </span>  <span class="Conceal">¦</span><span class="Constant"> .i         .</span>
 <span id="L2438" class="LineNr">2438 </span>  ]
 <span id="L2439" class="LineNr">2439 </span>  <span class="Comment"># now move up one line</span>
 <span id="L2440" class="LineNr">2440 </span>  assume-console [
-<span id="L2441" class="LineNr">2441 </span>    press up-arrow
+<span id="L2441" class="LineNr">2441 </span>  <span class="Conceal">¦</span> press up-arrow
 <span id="L2442" class="LineNr">2442 </span>  ]
 <span id="L2443" class="LineNr">2443 </span>  run [
-<span id="L2444" class="LineNr">2444 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2444" class="LineNr">2444 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2445" class="LineNr">2445 </span>  ]
 <span id="L2446" class="LineNr">2446 </span>  <span class="Comment"># screen shows partial wrapped line</span>
 <span id="L2447" class="LineNr">2447 </span>  screen-should-contain [
-<span id="L2448" class="LineNr">2448 </span>   <span class="Constant"> .          .</span>
-<span id="L2449" class="LineNr">2449 </span>   <span class="Constant"> .ef        .</span>
-<span id="L2450" class="LineNr">2450 </span>   <span class="Constant"> .g         .</span>
-<span id="L2451" class="LineNr">2451 </span>   <span class="Constant"> .h         .</span>
+<span id="L2448" class="LineNr">2448 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2449" class="LineNr">2449 </span>  <span class="Conceal">¦</span><span class="Constant"> .ef        .</span>
+<span id="L2450" class="LineNr">2450 </span>  <span class="Conceal">¦</span><span class="Constant"> .g         .</span>
+<span id="L2451" class="LineNr">2451 </span>  <span class="Conceal">¦</span><span class="Constant"> .h         .</span>
 <span id="L2452" class="LineNr">2452 </span>  ]
 <span id="L2453" class="LineNr">2453 </span>]
 <span id="L2454" class="LineNr">2454 </span>
@@ -2525,62 +2526,62 @@ if ('onhashchange' in window) {
 <span id="L2465" class="LineNr">2465 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L2466" class="LineNr">2466 </span>  <span class="Comment"># position cursor at top of second page</span>
 <span id="L2467" class="LineNr">2467 </span>  assume-console [
-<span id="L2468" class="LineNr">2468 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L2468" class="LineNr">2468 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L2469" class="LineNr">2469 </span>  ]
 <span id="L2470" class="LineNr">2470 </span>  run [
-<span id="L2471" class="LineNr">2471 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2471" class="LineNr">2471 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2472" class="LineNr">2472 </span>  ]
 <span id="L2473" class="LineNr">2473 </span>  screen-should-contain [
-<span id="L2474" class="LineNr">2474 </span>   <span class="Constant"> .          .</span>
-<span id="L2475" class="LineNr">2475 </span>   <span class="Constant"> .k         .</span>
-<span id="L2476" class="LineNr">2476 </span>   <span class="Constant"> .l         .</span>
-<span id="L2477" class="LineNr">2477 </span>   <span class="Constant"> .m         .</span>
-<span id="L2478" class="LineNr">2478 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
+<span id="L2474" class="LineNr">2474 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2475" class="LineNr">2475 </span>  <span class="Conceal">¦</span><span class="Constant"> .k         .</span>
+<span id="L2476" class="LineNr">2476 </span>  <span class="Conceal">¦</span><span class="Constant"> .l         .</span>
+<span id="L2477" class="LineNr">2477 </span>  <span class="Conceal">¦</span><span class="Constant"> .m         .</span>
+<span id="L2478" class="LineNr">2478 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌     .</span>
 <span id="L2479" class="LineNr">2479 </span>  ]
 <span id="L2480" class="LineNr">2480 </span>  <span class="Comment"># move up one line</span>
 <span id="L2481" class="LineNr">2481 </span>  assume-console [
-<span id="L2482" class="LineNr">2482 </span>    press up-arrow
+<span id="L2482" class="LineNr">2482 </span>  <span class="Conceal">¦</span> press up-arrow
 <span id="L2483" class="LineNr">2483 </span>  ]
 <span id="L2484" class="LineNr">2484 </span>  run [
-<span id="L2485" class="LineNr">2485 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2485" class="LineNr">2485 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2486" class="LineNr">2486 </span>  ]
 <span id="L2487" class="LineNr">2487 </span>  <span class="Comment"># screen shows partial wrapped line</span>
 <span id="L2488" class="LineNr">2488 </span>  screen-should-contain [
-<span id="L2489" class="LineNr">2489 </span>   <span class="Constant"> .          .</span>
-<span id="L2490" class="LineNr">2490 </span>   <span class="Constant"> .ij        .</span>
-<span id="L2491" class="LineNr">2491 </span>   <span class="Constant"> .k         .</span>
-<span id="L2492" class="LineNr">2492 </span>   <span class="Constant"> .l         .</span>
-<span id="L2493" class="LineNr">2493 </span>   <span class="Constant"> .m         .</span>
+<span id="L2489" class="LineNr">2489 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2490" class="LineNr">2490 </span>  <span class="Conceal">¦</span><span class="Constant"> .ij        .</span>
+<span id="L2491" class="LineNr">2491 </span>  <span class="Conceal">¦</span><span class="Constant"> .k         .</span>
+<span id="L2492" class="LineNr">2492 </span>  <span class="Conceal">¦</span><span class="Constant"> .l         .</span>
+<span id="L2493" class="LineNr">2493 </span>  <span class="Conceal">¦</span><span class="Constant"> .m         .</span>
 <span id="L2494" class="LineNr">2494 </span>  ]
 <span id="L2495" class="LineNr">2495 </span>  <span class="Comment"># move up a second line</span>
 <span id="L2496" class="LineNr">2496 </span>  assume-console [
-<span id="L2497" class="LineNr">2497 </span>    press up-arrow
+<span id="L2497" class="LineNr">2497 </span>  <span class="Conceal">¦</span> press up-arrow
 <span id="L2498" class="LineNr">2498 </span>  ]
 <span id="L2499" class="LineNr">2499 </span>  run [
-<span id="L2500" class="LineNr">2500 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2500" class="LineNr">2500 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2501" class="LineNr">2501 </span>  ]
 <span id="L2502" class="LineNr">2502 </span>  <span class="Comment"># screen shows partial wrapped line</span>
 <span id="L2503" class="LineNr">2503 </span>  screen-should-contain [
-<span id="L2504" class="LineNr">2504 </span>   <span class="Constant"> .          .</span>
-<span id="L2505" class="LineNr">2505 </span>   <span class="Constant"> .efgh↩     .</span>
-<span id="L2506" class="LineNr">2506 </span>   <span class="Constant"> .ij        .</span>
-<span id="L2507" class="LineNr">2507 </span>   <span class="Constant"> .k         .</span>
-<span id="L2508" class="LineNr">2508 </span>   <span class="Constant"> .l         .</span>
+<span id="L2504" class="LineNr">2504 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2505" class="LineNr">2505 </span>  <span class="Conceal">¦</span><span class="Constant"> .efgh↩     .</span>
+<span id="L2506" class="LineNr">2506 </span>  <span class="Conceal">¦</span><span class="Constant"> .ij        .</span>
+<span id="L2507" class="LineNr">2507 </span>  <span class="Conceal">¦</span><span class="Constant"> .k         .</span>
+<span id="L2508" class="LineNr">2508 </span>  <span class="Conceal">¦</span><span class="Constant"> .l         .</span>
 <span id="L2509" class="LineNr">2509 </span>  ]
 <span id="L2510" class="LineNr">2510 </span>  <span class="Comment"># move up a third line</span>
 <span id="L2511" class="LineNr">2511 </span>  assume-console [
-<span id="L2512" class="LineNr">2512 </span>    press up-arrow
+<span id="L2512" class="LineNr">2512 </span>  <span class="Conceal">¦</span> press up-arrow
 <span id="L2513" class="LineNr">2513 </span>  ]
 <span id="L2514" class="LineNr">2514 </span>  run [
-<span id="L2515" class="LineNr">2515 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2515" class="LineNr">2515 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2516" class="LineNr">2516 </span>  ]
 <span id="L2517" class="LineNr">2517 </span>  <span class="Comment"># screen shows partial wrapped line</span>
 <span id="L2518" class="LineNr">2518 </span>  screen-should-contain [
-<span id="L2519" class="LineNr">2519 </span>   <span class="Constant"> .          .</span>
-<span id="L2520" class="LineNr">2520 </span>   <span class="Constant"> .abcd↩     .</span>
-<span id="L2521" class="LineNr">2521 </span>   <span class="Constant"> .efgh↩     .</span>
-<span id="L2522" class="LineNr">2522 </span>   <span class="Constant"> .ij        .</span>
-<span id="L2523" class="LineNr">2523 </span>   <span class="Constant"> .k         .</span>
+<span id="L2519" class="LineNr">2519 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2520" class="LineNr">2520 </span>  <span class="Conceal">¦</span><span class="Constant"> .abcd↩     .</span>
+<span id="L2521" class="LineNr">2521 </span>  <span class="Conceal">¦</span><span class="Constant"> .efgh↩     .</span>
+<span id="L2522" class="LineNr">2522 </span>  <span class="Conceal">¦</span><span class="Constant"> .ij        .</span>
+<span id="L2523" class="LineNr">2523 </span>  <span class="Conceal">¦</span><span class="Constant"> .k         .</span>
 <span id="L2524" class="LineNr">2524 </span>  ]
 <span id="L2525" class="LineNr">2525 </span>]
 <span id="L2526" class="LineNr">2526 </span>
@@ -2599,37 +2600,37 @@ if ('onhashchange' in window) {
 <span id="L2539" class="LineNr">2539 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">6/right</span>
 <span id="L2540" class="LineNr">2540 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L2541" class="LineNr">2541 </span>  screen-should-contain [
-<span id="L2542" class="LineNr">2542 </span>   <span class="Constant"> .          .</span>
-<span id="L2543" class="LineNr">2543 </span>   <span class="Constant"> .abcde↩    .</span>
-<span id="L2544" class="LineNr">2544 </span>   <span class="Constant"> .f         .</span>
-<span id="L2545" class="LineNr">2545 </span>   <span class="Constant"> .g         .</span>
+<span id="L2542" class="LineNr">2542 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2543" class="LineNr">2543 </span>  <span class="Conceal">¦</span><span class="Constant"> .abcde↩    .</span>
+<span id="L2544" class="LineNr">2544 </span>  <span class="Conceal">¦</span><span class="Constant"> .f         .</span>
+<span id="L2545" class="LineNr">2545 </span>  <span class="Conceal">¦</span><span class="Constant"> .g         .</span>
 <span id="L2546" class="LineNr">2546 </span>  ]
 <span id="L2547" class="LineNr">2547 </span>  <span class="Comment"># position cursor at top of second page, just below wrapped line</span>
 <span id="L2548" class="LineNr">2548 </span>  assume-console [
-<span id="L2549" class="LineNr">2549 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L2549" class="LineNr">2549 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L2550" class="LineNr">2550 </span>  ]
 <span id="L2551" class="LineNr">2551 </span>  run [
-<span id="L2552" class="LineNr">2552 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2552" class="LineNr">2552 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2553" class="LineNr">2553 </span>  ]
 <span id="L2554" class="LineNr">2554 </span>  screen-should-contain [
-<span id="L2555" class="LineNr">2555 </span>   <span class="Constant"> .          .</span>
-<span id="L2556" class="LineNr">2556 </span>   <span class="Constant"> .g         .</span>
-<span id="L2557" class="LineNr">2557 </span>   <span class="Constant"> .h         .</span>
-<span id="L2558" class="LineNr">2558 </span>   <span class="Constant"> .i         .</span>
+<span id="L2555" class="LineNr">2555 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2556" class="LineNr">2556 </span>  <span class="Conceal">¦</span><span class="Constant"> .g         .</span>
+<span id="L2557" class="LineNr">2557 </span>  <span class="Conceal">¦</span><span class="Constant"> .h         .</span>
+<span id="L2558" class="LineNr">2558 </span>  <span class="Conceal">¦</span><span class="Constant"> .i         .</span>
 <span id="L2559" class="LineNr">2559 </span>  ]
 <span id="L2560" class="LineNr">2560 </span>  <span class="Comment"># now move up one line</span>
 <span id="L2561" class="LineNr">2561 </span>  assume-console [
-<span id="L2562" class="LineNr">2562 </span>    press up-arrow
+<span id="L2562" class="LineNr">2562 </span>  <span class="Conceal">¦</span> press up-arrow
 <span id="L2563" class="LineNr">2563 </span>  ]
 <span id="L2564" class="LineNr">2564 </span>  run [
-<span id="L2565" class="LineNr">2565 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2565" class="LineNr">2565 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2566" class="LineNr">2566 </span>  ]
 <span id="L2567" class="LineNr">2567 </span>  <span class="Comment"># screen shows partial wrapped line</span>
 <span id="L2568" class="LineNr">2568 </span>  screen-should-contain [
-<span id="L2569" class="LineNr">2569 </span>   <span class="Constant"> .          .</span>
-<span id="L2570" class="LineNr">2570 </span>   <span class="Constant"> .f         .</span>
-<span id="L2571" class="LineNr">2571 </span>   <span class="Constant"> .g         .</span>
-<span id="L2572" class="LineNr">2572 </span>   <span class="Constant"> .h         .</span>
+<span id="L2569" class="LineNr">2569 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2570" class="LineNr">2570 </span>  <span class="Conceal">¦</span><span class="Constant"> .f         .</span>
+<span id="L2571" class="LineNr">2571 </span>  <span class="Conceal">¦</span><span class="Constant"> .g         .</span>
+<span id="L2572" class="LineNr">2572 </span>  <span class="Conceal">¦</span><span class="Constant"> .h         .</span>
 <span id="L2573" class="LineNr">2573 </span>  ]
 <span id="L2574" class="LineNr">2574 </span>]
 <span id="L2575" class="LineNr">2575 </span>
@@ -2647,40 +2648,40 @@ if ('onhashchange' in window) {
 <span id="L2587" class="LineNr">2587 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">6/right</span>
 <span id="L2588" class="LineNr">2588 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L2589" class="LineNr">2589 </span>  assume-console [
-<span id="L2590" class="LineNr">2590 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L2590" class="LineNr">2590 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L2591" class="LineNr">2591 </span>  ]
 <span id="L2592" class="LineNr">2592 </span>  run [
-<span id="L2593" class="LineNr">2593 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2593" class="LineNr">2593 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2594" class="LineNr">2594 </span>  ]
 <span id="L2595" class="LineNr">2595 </span>  screen-should-contain [
-<span id="L2596" class="LineNr">2596 </span>   <span class="Constant"> .          .</span>
-<span id="L2597" class="LineNr">2597 </span>   <span class="Constant"> .          .</span>
-<span id="L2598" class="LineNr">2598 </span>   <span class="Constant"> .c         .</span>
-<span id="L2599" class="LineNr">2599 </span>   <span class="Constant"> .d         .</span>
+<span id="L2596" class="LineNr">2596 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2597" class="LineNr">2597 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2598" class="LineNr">2598 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
+<span id="L2599" class="LineNr">2599 </span>  <span class="Conceal">¦</span><span class="Constant"> .d         .</span>
 <span id="L2600" class="LineNr">2600 </span>  ]
 <span id="L2601" class="LineNr">2601 </span>  assume-console [
-<span id="L2602" class="LineNr">2602 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L2602" class="LineNr">2602 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L2603" class="LineNr">2603 </span>  ]
 <span id="L2604" class="LineNr">2604 </span>  run [
-<span id="L2605" class="LineNr">2605 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2605" class="LineNr">2605 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2606" class="LineNr">2606 </span>  ]
 <span id="L2607" class="LineNr">2607 </span>  screen-should-contain [
-<span id="L2608" class="LineNr">2608 </span>   <span class="Constant"> .          .</span>
-<span id="L2609" class="LineNr">2609 </span>   <span class="Constant"> .d         .</span>
-<span id="L2610" class="LineNr">2610 </span>   <span class="Constant"> .e         .</span>
-<span id="L2611" class="LineNr">2611 </span>   <span class="Constant"> .╌╌╌╌╌╌    .</span>
+<span id="L2608" class="LineNr">2608 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2609" class="LineNr">2609 </span>  <span class="Conceal">¦</span><span class="Constant"> .d         .</span>
+<span id="L2610" class="LineNr">2610 </span>  <span class="Conceal">¦</span><span class="Constant"> .e         .</span>
+<span id="L2611" class="LineNr">2611 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌    .</span>
 <span id="L2612" class="LineNr">2612 </span>  ]
 <span id="L2613" class="LineNr">2613 </span>  assume-console [
-<span id="L2614" class="LineNr">2614 </span>    press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
+<span id="L2614" class="LineNr">2614 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
 <span id="L2615" class="LineNr">2615 </span>  ]
 <span id="L2616" class="LineNr">2616 </span>  run [
-<span id="L2617" class="LineNr">2617 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2617" class="LineNr">2617 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2618" class="LineNr">2618 </span>  ]
 <span id="L2619" class="LineNr">2619 </span>  screen-should-contain [
-<span id="L2620" class="LineNr">2620 </span>   <span class="Constant"> .          .</span>
-<span id="L2621" class="LineNr">2621 </span>   <span class="Constant"> .          .</span>
-<span id="L2622" class="LineNr">2622 </span>   <span class="Constant"> .c         .</span>
-<span id="L2623" class="LineNr">2623 </span>   <span class="Constant"> .d         .</span>
+<span id="L2620" class="LineNr">2620 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2621" class="LineNr">2621 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2622" class="LineNr">2622 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
+<span id="L2623" class="LineNr">2623 </span>  <span class="Conceal">¦</span><span class="Constant"> .d         .</span>
 <span id="L2624" class="LineNr">2624 </span>  ]
 <span id="L2625" class="LineNr">2625 </span>]
 <span id="L2626" class="LineNr">2626 </span>
@@ -2698,36 +2699,36 @@ if ('onhashchange' in window) {
 <span id="L2638" class="LineNr">2638 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L2639" class="LineNr">2639 </span>  <span class="Comment"># position cursor at top of second page</span>
 <span id="L2640" class="LineNr">2640 </span>  assume-console [
-<span id="L2641" class="LineNr">2641 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L2641" class="LineNr">2641 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L2642" class="LineNr">2642 </span>  ]
 <span id="L2643" class="LineNr">2643 </span>  run [
-<span id="L2644" class="LineNr">2644 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2644" class="LineNr">2644 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2645" class="LineNr">2645 </span>  ]
 <span id="L2646" class="LineNr">2646 </span>  screen-should-contain [
-<span id="L2647" class="LineNr">2647 </span>   <span class="Constant"> .     .</span>
-<span id="L2648" class="LineNr">2648 </span>   <span class="Constant"> .c    .</span>
-<span id="L2649" class="LineNr">2649 </span>   <span class="Constant"> .d    .</span>
-<span id="L2650" class="LineNr">2650 </span>   <span class="Constant"> .e    .</span>
+<span id="L2647" class="LineNr">2647 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L2648" class="LineNr">2648 </span>  <span class="Conceal">¦</span><span class="Constant"> .c    .</span>
+<span id="L2649" class="LineNr">2649 </span>  <span class="Conceal">¦</span><span class="Constant"> .d    .</span>
+<span id="L2650" class="LineNr">2650 </span>  <span class="Conceal">¦</span><span class="Constant"> .e    .</span>
 <span id="L2651" class="LineNr">2651 </span>  ]
 <span id="L2652" class="LineNr">2652 </span>  <span class="Comment"># now try to move left</span>
 <span id="L2653" class="LineNr">2653 </span>  assume-console [
-<span id="L2654" class="LineNr">2654 </span>    press left-arrow
+<span id="L2654" class="LineNr">2654 </span>  <span class="Conceal">¦</span> press left-arrow
 <span id="L2655" class="LineNr">2655 </span>  ]
 <span id="L2656" class="LineNr">2656 </span>  run [
-<span id="L2657" class="LineNr">2657 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L2658" class="LineNr">2658 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L2659" class="LineNr">2659 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L2657" class="LineNr">2657 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2658" class="LineNr">2658 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L2659" class="LineNr">2659 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L2660" class="LineNr">2660 </span>  ]
 <span id="L2661" class="LineNr">2661 </span>  <span class="Comment"># screen scrolls</span>
 <span id="L2662" class="LineNr">2662 </span>  screen-should-contain [
-<span id="L2663" class="LineNr">2663 </span>   <span class="Constant"> .     .</span>
-<span id="L2664" class="LineNr">2664 </span>   <span class="Constant"> .b    .</span>
-<span id="L2665" class="LineNr">2665 </span>   <span class="Constant"> .c    .</span>
-<span id="L2666" class="LineNr">2666 </span>   <span class="Constant"> .d    .</span>
+<span id="L2663" class="LineNr">2663 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L2664" class="LineNr">2664 </span>  <span class="Conceal">¦</span><span class="Constant"> .b    .</span>
+<span id="L2665" class="LineNr">2665 </span>  <span class="Conceal">¦</span><span class="Constant"> .c    .</span>
+<span id="L2666" class="LineNr">2666 </span>  <span class="Conceal">¦</span><span class="Constant"> .d    .</span>
 <span id="L2667" class="LineNr">2667 </span>  ]
 <span id="L2668" class="LineNr">2668 </span>  memory-should-contain [
-<span id="L2669" class="LineNr">2669 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L2670" class="LineNr">2670 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L2669" class="LineNr">2669 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L2670" class="LineNr">2670 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L2671" class="LineNr">2671 </span>  ]
 <span id="L2672" class="LineNr">2672 </span>]
 <span id="L2673" class="LineNr">2673 </span>
@@ -2743,41 +2744,41 @@ if ('onhashchange' in window) {
 <span id="L2683" class="LineNr">2683 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L2684" class="LineNr">2684 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L2685" class="LineNr">2685 </span>  screen-should-contain [
-<span id="L2686" class="LineNr">2686 </span>   <span class="Constant"> .          .</span>
-<span id="L2687" class="LineNr">2687 </span>   <span class="Constant"> .a         .</span>
-<span id="L2688" class="LineNr">2688 </span>   <span class="Constant"> .b         .</span>
-<span id="L2689" class="LineNr">2689 </span>   <span class="Constant"> .c         .</span>
+<span id="L2686" class="LineNr">2686 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2687" class="LineNr">2687 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L2688" class="LineNr">2688 </span>  <span class="Conceal">¦</span><span class="Constant"> .b         .</span>
+<span id="L2689" class="LineNr">2689 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
 <span id="L2690" class="LineNr">2690 </span>  ]
 <span id="L2691" class="LineNr">2691 </span>  <span class="Comment"># position cursor at top of second page, then try to move up to start of</span>
 <span id="L2692" class="LineNr">2692 </span>  <span class="Comment"># text</span>
 <span id="L2693" class="LineNr">2693 </span>  assume-console [
-<span id="L2694" class="LineNr">2694 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
-<span id="L2695" class="LineNr">2695 </span>    press up-arrow
-<span id="L2696" class="LineNr">2696 </span>    press up-arrow
+<span id="L2694" class="LineNr">2694 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L2695" class="LineNr">2695 </span>  <span class="Conceal">¦</span> press up-arrow
+<span id="L2696" class="LineNr">2696 </span>  <span class="Conceal">¦</span> press up-arrow
 <span id="L2697" class="LineNr">2697 </span>  ]
 <span id="L2698" class="LineNr">2698 </span>  run [
-<span id="L2699" class="LineNr">2699 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2699" class="LineNr">2699 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2700" class="LineNr">2700 </span>  ]
 <span id="L2701" class="LineNr">2701 </span>  <span class="Comment"># screen slides by one line</span>
 <span id="L2702" class="LineNr">2702 </span>  screen-should-contain [
-<span id="L2703" class="LineNr">2703 </span>   <span class="Constant"> .          .</span>
-<span id="L2704" class="LineNr">2704 </span>   <span class="Constant"> .a         .</span>
-<span id="L2705" class="LineNr">2705 </span>   <span class="Constant"> .b         .</span>
-<span id="L2706" class="LineNr">2706 </span>   <span class="Constant"> .c         .</span>
+<span id="L2703" class="LineNr">2703 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2704" class="LineNr">2704 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L2705" class="LineNr">2705 </span>  <span class="Conceal">¦</span><span class="Constant"> .b         .</span>
+<span id="L2706" class="LineNr">2706 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
 <span id="L2707" class="LineNr">2707 </span>  ]
 <span id="L2708" class="LineNr">2708 </span>  <span class="Comment"># try to move up again</span>
 <span id="L2709" class="LineNr">2709 </span>  assume-console [
-<span id="L2710" class="LineNr">2710 </span>    press up-arrow
+<span id="L2710" class="LineNr">2710 </span>  <span class="Conceal">¦</span> press up-arrow
 <span id="L2711" class="LineNr">2711 </span>  ]
 <span id="L2712" class="LineNr">2712 </span>  run [
-<span id="L2713" class="LineNr">2713 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2713" class="LineNr">2713 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2714" class="LineNr">2714 </span>  ]
 <span id="L2715" class="LineNr">2715 </span>  <span class="Comment"># screen remains unchanged</span>
 <span id="L2716" class="LineNr">2716 </span>  screen-should-contain [
-<span id="L2717" class="LineNr">2717 </span>   <span class="Constant"> .          .</span>
-<span id="L2718" class="LineNr">2718 </span>   <span class="Constant"> .a         .</span>
-<span id="L2719" class="LineNr">2719 </span>   <span class="Constant"> .b         .</span>
-<span id="L2720" class="LineNr">2720 </span>   <span class="Constant"> .c         .</span>
+<span id="L2717" class="LineNr">2717 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2718" class="LineNr">2718 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L2719" class="LineNr">2719 </span>  <span class="Conceal">¦</span><span class="Constant"> .b         .</span>
+<span id="L2720" class="LineNr">2720 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
 <span id="L2721" class="LineNr">2721 </span>  ]
 <span id="L2722" class="LineNr">2722 </span>]
 <span id="L2723" class="LineNr">2723 </span>
@@ -2793,54 +2794,54 @@ if ('onhashchange' in window) {
 <span id="L2733" class="LineNr">2733 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L2734" class="LineNr">2734 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L2735" class="LineNr">2735 </span>  screen-should-contain [
-<span id="L2736" class="LineNr">2736 </span>   <span class="Constant"> .          .</span>
-<span id="L2737" class="LineNr">2737 </span>   <span class="Constant"> .a         .</span>
-<span id="L2738" class="LineNr">2738 </span>   <span class="Constant"> .b         .</span>
-<span id="L2739" class="LineNr">2739 </span>   <span class="Constant"> .c         .</span>
+<span id="L2736" class="LineNr">2736 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2737" class="LineNr">2737 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L2738" class="LineNr">2738 </span>  <span class="Conceal">¦</span><span class="Constant"> .b         .</span>
+<span id="L2739" class="LineNr">2739 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
 <span id="L2740" class="LineNr">2740 </span>  ]
 <span id="L2741" class="LineNr">2741 </span>  <span class="Comment"># scroll down</span>
 <span id="L2742" class="LineNr">2742 </span>  assume-console [
-<span id="L2743" class="LineNr">2743 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L2743" class="LineNr">2743 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L2744" class="LineNr">2744 </span>  ]
 <span id="L2745" class="LineNr">2745 </span>  run [
-<span id="L2746" class="LineNr">2746 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2746" class="LineNr">2746 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2747" class="LineNr">2747 </span>  ]
 <span id="L2748" class="LineNr">2748 </span>  <span class="Comment"># screen shows next page</span>
 <span id="L2749" class="LineNr">2749 </span>  screen-should-contain [
-<span id="L2750" class="LineNr">2750 </span>   <span class="Constant"> .          .</span>
-<span id="L2751" class="LineNr">2751 </span>   <span class="Constant"> .c         .</span>
-<span id="L2752" class="LineNr">2752 </span>   <span class="Constant"> .d         .</span>
-<span id="L2753" class="LineNr">2753 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L2750" class="LineNr">2750 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2751" class="LineNr">2751 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
+<span id="L2752" class="LineNr">2752 </span>  <span class="Conceal">¦</span><span class="Constant"> .d         .</span>
+<span id="L2753" class="LineNr">2753 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
 <span id="L2754" class="LineNr">2754 </span>  ]
 <span id="L2755" class="LineNr">2755 </span>]
 <span id="L2756" class="LineNr">2756 </span>
 <span id="L2757" class="LineNr">2757 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L183'>&lt;handle-special-character&gt;</a></span> [
 <span id="L2758" class="LineNr">2758 </span>  <span class="Delimiter">{</span>
-<span id="L2759" class="LineNr">2759 </span>    page-down?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">6/ctrl-f</span>
-<span id="L2760" class="LineNr">2760 </span>    <span class="muControl">break-unless</span> page-down?
-<span id="L2761" class="LineNr">2761 </span>    old-top:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
-<span id="L2762" class="LineNr">2762 </span><span class="Constant">    &lt;move-cursor-begin&gt;</span>
-<span id="L2763" class="LineNr">2763 </span>    <a href='003-shortcuts.mu.html#L2789'>page-down</a> editor
-<span id="L2764" class="LineNr">2764 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
-<span id="L2765" class="LineNr">2765 </span><span class="Constant">    &lt;move-cursor-end&gt;</span>
-<span id="L2766" class="LineNr">2766 </span>    top-of-screen:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
-<span id="L2767" class="LineNr">2767 </span>    movement?:bool <span class="Special">&lt;-</span> not-equal top-of-screen, old-top
-<span id="L2768" class="LineNr">2768 </span>    <span class="muControl">return</span> movement?/go-render
+<span id="L2759" class="LineNr">2759 </span>  <span class="Conceal">¦</span> page-down?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">6/ctrl-f</span>
+<span id="L2760" class="LineNr">2760 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> page-down?
+<span id="L2761" class="LineNr">2761 </span>  <span class="Conceal">¦</span> old-top:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
+<span id="L2762" class="LineNr">2762 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-begin&gt;</span>
+<span id="L2763" class="LineNr">2763 </span>  <span class="Conceal">¦</span> <a href='003-shortcuts.mu.html#L2789'>page-down</a> editor
+<span id="L2764" class="LineNr">2764 </span>  <span class="Conceal">¦</span> undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
+<span id="L2765" class="LineNr">2765 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-end&gt;</span>
+<span id="L2766" class="LineNr">2766 </span>  <span class="Conceal">¦</span> top-of-screen:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
+<span id="L2767" class="LineNr">2767 </span>  <span class="Conceal">¦</span> movement?:bool <span class="Special">&lt;-</span> not-equal top-of-screen, old-top
+<span id="L2768" class="LineNr">2768 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> movement?/go-render
 <span id="L2769" class="LineNr">2769 </span>  <span class="Delimiter">}</span>
 <span id="L2770" class="LineNr">2770 </span>]
 <span id="L2771" class="LineNr">2771 </span>
 <span id="L2772" class="LineNr">2772 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L197'>&lt;handle-special-key&gt;</a></span> [
 <span id="L2773" class="LineNr">2773 </span>  <span class="Delimiter">{</span>
-<span id="L2774" class="LineNr">2774 </span>    page-down?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65518/page-down</span>
-<span id="L2775" class="LineNr">2775 </span>    <span class="muControl">break-unless</span> page-down?
-<span id="L2776" class="LineNr">2776 </span>    old-top:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
-<span id="L2777" class="LineNr">2777 </span><span class="Constant">    &lt;move-cursor-begin&gt;</span>
-<span id="L2778" class="LineNr">2778 </span>    <a href='003-shortcuts.mu.html#L2789'>page-down</a> editor
-<span id="L2779" class="LineNr">2779 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
-<span id="L2780" class="LineNr">2780 </span><span class="Constant">    &lt;move-cursor-end&gt;</span>
-<span id="L2781" class="LineNr">2781 </span>    top-of-screen:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
-<span id="L2782" class="LineNr">2782 </span>    movement?:bool <span class="Special">&lt;-</span> not-equal top-of-screen, old-top
-<span id="L2783" class="LineNr">2783 </span>    <span class="muControl">return</span> movement?/go-render
+<span id="L2774" class="LineNr">2774 </span>  <span class="Conceal">¦</span> page-down?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65518/page-down</span>
+<span id="L2775" class="LineNr">2775 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> page-down?
+<span id="L2776" class="LineNr">2776 </span>  <span class="Conceal">¦</span> old-top:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
+<span id="L2777" class="LineNr">2777 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-begin&gt;</span>
+<span id="L2778" class="LineNr">2778 </span>  <span class="Conceal">¦</span> <a href='003-shortcuts.mu.html#L2789'>page-down</a> editor
+<span id="L2779" class="LineNr">2779 </span>  <span class="Conceal">¦</span> undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
+<span id="L2780" class="LineNr">2780 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-end&gt;</span>
+<span id="L2781" class="LineNr">2781 </span>  <span class="Conceal">¦</span> top-of-screen:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
+<span id="L2782" class="LineNr">2782 </span>  <span class="Conceal">¦</span> movement?:bool <span class="Special">&lt;-</span> not-equal top-of-screen, old-top
+<span id="L2783" class="LineNr">2783 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> movement?/go-render
 <span id="L2784" class="LineNr">2784 </span>  <span class="Delimiter">}</span>
 <span id="L2785" class="LineNr">2785 </span>]
 <span id="L2786" class="LineNr">2786 </span>
@@ -2858,11 +2859,11 @@ if ('onhashchange' in window) {
 <span id="L2798" class="LineNr">2798 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
 <span id="L2799" class="LineNr">2799 </span>  <span class="Comment"># keep one line in common with previous page</span>
 <span id="L2800" class="LineNr">2800 </span>  <span class="Delimiter">{</span>
-<span id="L2801" class="LineNr">2801 </span>    <a href='../065duplex_list.mu.html#L516'>last</a>:char <span class="Special">&lt;-</span> get *before-cursor, <span class="Constant">value:offset</span>
-<span id="L2802" class="LineNr">2802 </span>    newline?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L516'>last</a>, <span class="Constant">10/newline</span>
-<span id="L2803" class="LineNr">2803 </span>    <span class="muControl">break-unless</span> newline?:bool
-<span id="L2804" class="LineNr">2804 </span>    before-cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> before-cursor
-<span id="L2805" class="LineNr">2805 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
+<span id="L2801" class="LineNr">2801 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L516'>last</a>:char <span class="Special">&lt;-</span> get *before-cursor, <span class="Constant">value:offset</span>
+<span id="L2802" class="LineNr">2802 </span>  <span class="Conceal">¦</span> newline?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L516'>last</a>, <span class="Constant">10/newline</span>
+<span id="L2803" class="LineNr">2803 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> newline?:bool
+<span id="L2804" class="LineNr">2804 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> before-cursor
+<span id="L2805" class="LineNr">2805 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
 <span id="L2806" class="LineNr">2806 </span>  <span class="Delimiter">}</span>
 <span id="L2807" class="LineNr">2807 </span>  <span class="Comment"># move cursor and top-of-screen to start of that line</span>
 <span id="L2808" class="LineNr">2808 </span>  <a href='003-shortcuts.mu.html#L1350'>move-to-start-of-line</a> editor
@@ -2878,24 +2879,24 @@ if ('onhashchange' in window) {
 <span id="L2818" class="LineNr">2818 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L2819" class="LineNr">2819 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L2820" class="LineNr">2820 </span>  screen-should-contain [
-<span id="L2821" class="LineNr">2821 </span>   <span class="Constant"> .          .</span>
-<span id="L2822" class="LineNr">2822 </span>   <span class="Constant"> .a         .</span>
-<span id="L2823" class="LineNr">2823 </span>   <span class="Constant"> .b         .</span>
-<span id="L2824" class="LineNr">2824 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L2821" class="LineNr">2821 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2822" class="LineNr">2822 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L2823" class="LineNr">2823 </span>  <span class="Conceal">¦</span><span class="Constant"> .b         .</span>
+<span id="L2824" class="LineNr">2824 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
 <span id="L2825" class="LineNr">2825 </span>  ]
 <span id="L2826" class="LineNr">2826 </span>  <span class="Comment"># scroll down</span>
 <span id="L2827" class="LineNr">2827 </span>  assume-console [
-<span id="L2828" class="LineNr">2828 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L2828" class="LineNr">2828 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L2829" class="LineNr">2829 </span>  ]
 <span id="L2830" class="LineNr">2830 </span>  run [
-<span id="L2831" class="LineNr">2831 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2831" class="LineNr">2831 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2832" class="LineNr">2832 </span>  ]
 <span id="L2833" class="LineNr">2833 </span>  <span class="Comment"># screen remains unmodified</span>
 <span id="L2834" class="LineNr">2834 </span>  screen-should-contain [
-<span id="L2835" class="LineNr">2835 </span>   <span class="Constant"> .          .</span>
-<span id="L2836" class="LineNr">2836 </span>   <span class="Constant"> .a         .</span>
-<span id="L2837" class="LineNr">2837 </span>   <span class="Constant"> .b         .</span>
-<span id="L2838" class="LineNr">2838 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L2835" class="LineNr">2835 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2836" class="LineNr">2836 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L2837" class="LineNr">2837 </span>  <span class="Conceal">¦</span><span class="Constant"> .b         .</span>
+<span id="L2838" class="LineNr">2838 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
 <span id="L2839" class="LineNr">2839 </span>  ]
 <span id="L2840" class="LineNr">2840 </span>]
 <span id="L2841" class="LineNr">2841 </span>
@@ -2912,24 +2913,24 @@ if ('onhashchange' in window) {
 <span id="L2852" class="LineNr">2852 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L2853" class="LineNr">2853 </span>  <span class="Comment"># some part of last line is not displayed</span>
 <span id="L2854" class="LineNr">2854 </span>  screen-should-contain [
-<span id="L2855" class="LineNr">2855 </span>   <span class="Constant"> .          .</span>
-<span id="L2856" class="LineNr">2856 </span>   <span class="Constant"> .a         .</span>
-<span id="L2857" class="LineNr">2857 </span>   <span class="Constant"> .b         .</span>
-<span id="L2858" class="LineNr">2858 </span>   <span class="Constant"> .cde↩      .</span>
+<span id="L2855" class="LineNr">2855 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2856" class="LineNr">2856 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L2857" class="LineNr">2857 </span>  <span class="Conceal">¦</span><span class="Constant"> .b         .</span>
+<span id="L2858" class="LineNr">2858 </span>  <span class="Conceal">¦</span><span class="Constant"> .cde↩      .</span>
 <span id="L2859" class="LineNr">2859 </span>  ]
 <span id="L2860" class="LineNr">2860 </span>  <span class="Comment"># scroll down</span>
 <span id="L2861" class="LineNr">2861 </span>  assume-console [
-<span id="L2862" class="LineNr">2862 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L2862" class="LineNr">2862 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L2863" class="LineNr">2863 </span>  ]
 <span id="L2864" class="LineNr">2864 </span>  run [
-<span id="L2865" class="LineNr">2865 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2865" class="LineNr">2865 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2866" class="LineNr">2866 </span>  ]
 <span id="L2867" class="LineNr">2867 </span>  <span class="Comment"># screen shows entire wrapped line</span>
 <span id="L2868" class="LineNr">2868 </span>  screen-should-contain [
-<span id="L2869" class="LineNr">2869 </span>   <span class="Constant"> .          .</span>
-<span id="L2870" class="LineNr">2870 </span>   <span class="Constant"> .cde↩      .</span>
-<span id="L2871" class="LineNr">2871 </span>   <span class="Constant"> .fgh       .</span>
-<span id="L2872" class="LineNr">2872 </span>   <span class="Constant"> .╌╌╌╌      .</span>
+<span id="L2869" class="LineNr">2869 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2870" class="LineNr">2870 </span>  <span class="Conceal">¦</span><span class="Constant"> .cde↩      .</span>
+<span id="L2871" class="LineNr">2871 </span>  <span class="Conceal">¦</span><span class="Constant"> .fgh       .</span>
+<span id="L2872" class="LineNr">2872 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌      .</span>
 <span id="L2873" class="LineNr">2873 </span>  ]
 <span id="L2874" class="LineNr">2874 </span>]
 <span id="L2875" class="LineNr">2875 </span>
@@ -2945,24 +2946,24 @@ if ('onhashchange' in window) {
 <span id="L2885" class="LineNr">2885 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L2886" class="LineNr">2886 </span>  <span class="Comment"># some part of last line is not displayed</span>
 <span id="L2887" class="LineNr">2887 </span>  screen-should-contain [
-<span id="L2888" class="LineNr">2888 </span>   <span class="Constant"> .          .</span>
-<span id="L2889" class="LineNr">2889 </span>   <span class="Constant"> .a         .</span>
-<span id="L2890" class="LineNr">2890 </span>   <span class="Constant"> .bcd↩      .</span>
-<span id="L2891" class="LineNr">2891 </span>   <span class="Constant"> .efg↩      .</span>
+<span id="L2888" class="LineNr">2888 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2889" class="LineNr">2889 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L2890" class="LineNr">2890 </span>  <span class="Conceal">¦</span><span class="Constant"> .bcd↩      .</span>
+<span id="L2891" class="LineNr">2891 </span>  <span class="Conceal">¦</span><span class="Constant"> .efg↩      .</span>
 <span id="L2892" class="LineNr">2892 </span>  ]
 <span id="L2893" class="LineNr">2893 </span>  <span class="Comment"># scroll down</span>
 <span id="L2894" class="LineNr">2894 </span>  assume-console [
-<span id="L2895" class="LineNr">2895 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L2895" class="LineNr">2895 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L2896" class="LineNr">2896 </span>  ]
 <span id="L2897" class="LineNr">2897 </span>  run [
-<span id="L2898" class="LineNr">2898 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2898" class="LineNr">2898 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2899" class="LineNr">2899 </span>  ]
 <span id="L2900" class="LineNr">2900 </span>  <span class="Comment"># screen shows entire wrapped line</span>
 <span id="L2901" class="LineNr">2901 </span>  screen-should-contain [
-<span id="L2902" class="LineNr">2902 </span>   <span class="Constant"> .          .</span>
-<span id="L2903" class="LineNr">2903 </span>   <span class="Constant"> .bcd↩      .</span>
-<span id="L2904" class="LineNr">2904 </span>   <span class="Constant"> .efg↩      .</span>
-<span id="L2905" class="LineNr">2905 </span>   <span class="Constant"> .h         .</span>
+<span id="L2902" class="LineNr">2902 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2903" class="LineNr">2903 </span>  <span class="Conceal">¦</span><span class="Constant"> .bcd↩      .</span>
+<span id="L2904" class="LineNr">2904 </span>  <span class="Conceal">¦</span><span class="Constant"> .efg↩      .</span>
+<span id="L2905" class="LineNr">2905 </span>  <span class="Conceal">¦</span><span class="Constant"> .h         .</span>
 <span id="L2906" class="LineNr">2906 </span>  ]
 <span id="L2907" class="LineNr">2907 </span>]
 <span id="L2908" class="LineNr">2908 </span>
@@ -2978,69 +2979,69 @@ if ('onhashchange' in window) {
 <span id="L2918" class="LineNr">2918 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L2919" class="LineNr">2919 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L2920" class="LineNr">2920 </span>  screen-should-contain [
-<span id="L2921" class="LineNr">2921 </span>   <span class="Constant"> .          .</span>
-<span id="L2922" class="LineNr">2922 </span>   <span class="Constant"> .a         .</span>
-<span id="L2923" class="LineNr">2923 </span>   <span class="Constant"> .b         .</span>
-<span id="L2924" class="LineNr">2924 </span>   <span class="Constant"> .c         .</span>
+<span id="L2921" class="LineNr">2921 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2922" class="LineNr">2922 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L2923" class="LineNr">2923 </span>  <span class="Conceal">¦</span><span class="Constant"> .b         .</span>
+<span id="L2924" class="LineNr">2924 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
 <span id="L2925" class="LineNr">2925 </span>  ]
 <span id="L2926" class="LineNr">2926 </span>  <span class="Comment"># scroll down</span>
 <span id="L2927" class="LineNr">2927 </span>  assume-console [
-<span id="L2928" class="LineNr">2928 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L2928" class="LineNr">2928 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L2929" class="LineNr">2929 </span>  ]
 <span id="L2930" class="LineNr">2930 </span>  run [
-<span id="L2931" class="LineNr">2931 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2931" class="LineNr">2931 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2932" class="LineNr">2932 </span>  ]
 <span id="L2933" class="LineNr">2933 </span>  <span class="Comment"># screen shows next page</span>
 <span id="L2934" class="LineNr">2934 </span>  screen-should-contain [
-<span id="L2935" class="LineNr">2935 </span>   <span class="Constant"> .          .</span>
-<span id="L2936" class="LineNr">2936 </span>   <span class="Constant"> .c         .</span>
-<span id="L2937" class="LineNr">2937 </span>   <span class="Constant"> .d         .</span>
-<span id="L2938" class="LineNr">2938 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L2935" class="LineNr">2935 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2936" class="LineNr">2936 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
+<span id="L2937" class="LineNr">2937 </span>  <span class="Conceal">¦</span><span class="Constant"> .d         .</span>
+<span id="L2938" class="LineNr">2938 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
 <span id="L2939" class="LineNr">2939 </span>  ]
 <span id="L2940" class="LineNr">2940 </span>  <span class="Comment"># scroll back up</span>
 <span id="L2941" class="LineNr">2941 </span>  assume-console [
-<span id="L2942" class="LineNr">2942 </span>    press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
+<span id="L2942" class="LineNr">2942 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
 <span id="L2943" class="LineNr">2943 </span>  ]
 <span id="L2944" class="LineNr">2944 </span>  run [
-<span id="L2945" class="LineNr">2945 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2945" class="LineNr">2945 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2946" class="LineNr">2946 </span>  ]
 <span id="L2947" class="LineNr">2947 </span>  <span class="Comment"># screen shows original page again</span>
 <span id="L2948" class="LineNr">2948 </span>  screen-should-contain [
-<span id="L2949" class="LineNr">2949 </span>   <span class="Constant"> .          .</span>
-<span id="L2950" class="LineNr">2950 </span>   <span class="Constant"> .a         .</span>
-<span id="L2951" class="LineNr">2951 </span>   <span class="Constant"> .b         .</span>
-<span id="L2952" class="LineNr">2952 </span>   <span class="Constant"> .c         .</span>
+<span id="L2949" class="LineNr">2949 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2950" class="LineNr">2950 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L2951" class="LineNr">2951 </span>  <span class="Conceal">¦</span><span class="Constant"> .b         .</span>
+<span id="L2952" class="LineNr">2952 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
 <span id="L2953" class="LineNr">2953 </span>  ]
 <span id="L2954" class="LineNr">2954 </span>]
 <span id="L2955" class="LineNr">2955 </span>
 <span id="L2956" class="LineNr">2956 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L183'>&lt;handle-special-character&gt;</a></span> [
 <span id="L2957" class="LineNr">2957 </span>  <span class="Delimiter">{</span>
-<span id="L2958" class="LineNr">2958 </span>    page-up?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">2/ctrl-b</span>
-<span id="L2959" class="LineNr">2959 </span>    <span class="muControl">break-unless</span> page-up?
-<span id="L2960" class="LineNr">2960 </span>    old-top:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
-<span id="L2961" class="LineNr">2961 </span><span class="Constant">    &lt;move-cursor-begin&gt;</span>
-<span id="L2962" class="LineNr">2962 </span>    editor <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2987'>page-up</a> editor, <a href='../081print.mu.html#L594'>screen-height</a>
-<span id="L2963" class="LineNr">2963 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
-<span id="L2964" class="LineNr">2964 </span><span class="Constant">    &lt;move-cursor-end&gt;</span>
-<span id="L2965" class="LineNr">2965 </span>    top-of-screen:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
-<span id="L2966" class="LineNr">2966 </span>    movement?:bool <span class="Special">&lt;-</span> not-equal top-of-screen, old-top
-<span id="L2967" class="LineNr">2967 </span>    <span class="muControl">return</span> movement?/go-render
+<span id="L2958" class="LineNr">2958 </span>  <span class="Conceal">¦</span> page-up?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">2/ctrl-b</span>
+<span id="L2959" class="LineNr">2959 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> page-up?
+<span id="L2960" class="LineNr">2960 </span>  <span class="Conceal">¦</span> old-top:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
+<span id="L2961" class="LineNr">2961 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-begin&gt;</span>
+<span id="L2962" class="LineNr">2962 </span>  <span class="Conceal">¦</span> editor <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2987'>page-up</a> editor, <a href='../081print.mu.html#L594'>screen-height</a>
+<span id="L2963" class="LineNr">2963 </span>  <span class="Conceal">¦</span> undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
+<span id="L2964" class="LineNr">2964 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-end&gt;</span>
+<span id="L2965" class="LineNr">2965 </span>  <span class="Conceal">¦</span> top-of-screen:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
+<span id="L2966" class="LineNr">2966 </span>  <span class="Conceal">¦</span> movement?:bool <span class="Special">&lt;-</span> not-equal top-of-screen, old-top
+<span id="L2967" class="LineNr">2967 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> movement?/go-render
 <span id="L2968" class="LineNr">2968 </span>  <span class="Delimiter">}</span>
 <span id="L2969" class="LineNr">2969 </span>]
 <span id="L2970" class="LineNr">2970 </span>
 <span id="L2971" class="LineNr">2971 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L197'>&lt;handle-special-key&gt;</a></span> [
 <span id="L2972" class="LineNr">2972 </span>  <span class="Delimiter">{</span>
-<span id="L2973" class="LineNr">2973 </span>    page-up?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65519/page-up</span>
-<span id="L2974" class="LineNr">2974 </span>    <span class="muControl">break-unless</span> page-up?
-<span id="L2975" class="LineNr">2975 </span>    old-top:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
-<span id="L2976" class="LineNr">2976 </span><span class="Constant">    &lt;move-cursor-begin&gt;</span>
-<span id="L2977" class="LineNr">2977 </span>    editor <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2987'>page-up</a> editor, <a href='../081print.mu.html#L594'>screen-height</a>
-<span id="L2978" class="LineNr">2978 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
-<span id="L2979" class="LineNr">2979 </span><span class="Constant">    &lt;move-cursor-end&gt;</span>
-<span id="L2980" class="LineNr">2980 </span>    top-of-screen:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
-<span id="L2981" class="LineNr">2981 </span>    movement?:bool <span class="Special">&lt;-</span> not-equal top-of-screen, old-top
-<span id="L2982" class="LineNr">2982 </span>    <span class="Comment"># don't bother re-rendering if nothing changed. todo: test this</span>
-<span id="L2983" class="LineNr">2983 </span>    <span class="muControl">return</span> movement?/go-render
+<span id="L2973" class="LineNr">2973 </span>  <span class="Conceal">¦</span> page-up?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65519/page-up</span>
+<span id="L2974" class="LineNr">2974 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> page-up?
+<span id="L2975" class="LineNr">2975 </span>  <span class="Conceal">¦</span> old-top:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
+<span id="L2976" class="LineNr">2976 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-begin&gt;</span>
+<span id="L2977" class="LineNr">2977 </span>  <span class="Conceal">¦</span> editor <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2987'>page-up</a> editor, <a href='../081print.mu.html#L594'>screen-height</a>
+<span id="L2978" class="LineNr">2978 </span>  <span class="Conceal">¦</span> undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
+<span id="L2979" class="LineNr">2979 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;move-cursor-end&gt;</span>
+<span id="L2980" class="LineNr">2980 </span>  <span class="Conceal">¦</span> top-of-screen:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
+<span id="L2981" class="LineNr">2981 </span>  <span class="Conceal">¦</span> movement?:bool <span class="Special">&lt;-</span> not-equal top-of-screen, old-top
+<span id="L2982" class="LineNr">2982 </span>  <span class="Conceal">¦</span> <span class="Comment"># don't bother re-rendering if nothing changed. todo: test this</span>
+<span id="L2983" class="LineNr">2983 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> movement?/go-render
 <span id="L2984" class="LineNr">2984 </span>  <span class="Delimiter">}</span>
 <span id="L2985" class="LineNr">2985 </span>]
 <span id="L2986" class="LineNr">2986 </span>
@@ -3051,14 +3052,14 @@ if ('onhashchange' in window) {
 <span id="L2991" class="LineNr">2991 </span>  count:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
 <span id="L2992" class="LineNr">2992 </span>  top-of-screen:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
 <span id="L2993" class="LineNr">2993 </span>  <span class="Delimiter">{</span>
-<span id="L2994" class="LineNr">2994 </span>    done?:bool <span class="Special">&lt;-</span> greater-or-equal count, max
-<span id="L2995" class="LineNr">2995 </span>    <span class="muControl">break-if</span> done?
-<span id="L2996" class="LineNr">2996 </span>    <a href='../065duplex_list.mu.html#L36'>prev</a>:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2367'>before-previous-line</a> top-of-screen, editor
-<span id="L2997" class="LineNr">2997 </span>    <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L36'>prev</a>
-<span id="L2998" class="LineNr">2998 </span>    top-of-screen <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
-<span id="L2999" class="LineNr">2999 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top-of-screen
-<span id="L3000" class="LineNr">3000 </span>    count <span class="Special">&lt;-</span> add count,<span class="Constant"> 1</span>
-<span id="L3001" class="LineNr">3001 </span>    <span class="muControl">loop</span>
+<span id="L2994" class="LineNr">2994 </span>  <span class="Conceal">¦</span> done?:bool <span class="Special">&lt;-</span> greater-or-equal count, max
+<span id="L2995" class="LineNr">2995 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
+<span id="L2996" class="LineNr">2996 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a>:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2367'>before-previous-line</a> top-of-screen, editor
+<span id="L2997" class="LineNr">2997 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L2998" class="LineNr">2998 </span>  <span class="Conceal">¦</span> top-of-screen <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L2999" class="LineNr">2999 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top-of-screen
+<span id="L3000" class="LineNr">3000 </span>  <span class="Conceal">¦</span> count <span class="Special">&lt;-</span> add count,<span class="Constant"> 1</span>
+<span id="L3001" class="LineNr">3001 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L3002" class="LineNr">3002 </span>  <span class="Delimiter">}</span>
 <span id="L3003" class="LineNr">3003 </span>]
 <span id="L3004" class="LineNr">3004 </span>
@@ -3078,53 +3079,53 @@ if ('onhashchange' in window) {
 <span id="L3018" class="LineNr">3018 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L3019" class="LineNr">3019 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L3020" class="LineNr">3020 </span>  screen-should-contain [
-<span id="L3021" class="LineNr">3021 </span>   <span class="Constant"> .          .</span>
-<span id="L3022" class="LineNr">3022 </span>   <span class="Constant"> .a         .</span>
-<span id="L3023" class="LineNr">3023 </span>   <span class="Constant"> .b         .</span>
-<span id="L3024" class="LineNr">3024 </span>   <span class="Constant"> .c         .</span>
+<span id="L3021" class="LineNr">3021 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L3022" class="LineNr">3022 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L3023" class="LineNr">3023 </span>  <span class="Conceal">¦</span><span class="Constant"> .b         .</span>
+<span id="L3024" class="LineNr">3024 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
 <span id="L3025" class="LineNr">3025 </span>  ]
 <span id="L3026" class="LineNr">3026 </span>  <span class="Comment"># scroll down two pages</span>
 <span id="L3027" class="LineNr">3027 </span>  assume-console [
-<span id="L3028" class="LineNr">3028 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
-<span id="L3029" class="LineNr">3029 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L3028" class="LineNr">3028 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L3029" class="LineNr">3029 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L3030" class="LineNr">3030 </span>  ]
 <span id="L3031" class="LineNr">3031 </span>  run [
-<span id="L3032" class="LineNr">3032 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L3032" class="LineNr">3032 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L3033" class="LineNr">3033 </span>  ]
 <span id="L3034" class="LineNr">3034 </span>  <span class="Comment"># screen shows third page</span>
 <span id="L3035" class="LineNr">3035 </span>  screen-should-contain [
-<span id="L3036" class="LineNr">3036 </span>   <span class="Constant"> .          .</span>
-<span id="L3037" class="LineNr">3037 </span>   <span class="Constant"> .e         .</span>
-<span id="L3038" class="LineNr">3038 </span>   <span class="Constant"> .f         .</span>
-<span id="L3039" class="LineNr">3039 </span>   <span class="Constant"> .g         .</span>
+<span id="L3036" class="LineNr">3036 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L3037" class="LineNr">3037 </span>  <span class="Conceal">¦</span><span class="Constant"> .e         .</span>
+<span id="L3038" class="LineNr">3038 </span>  <span class="Conceal">¦</span><span class="Constant"> .f         .</span>
+<span id="L3039" class="LineNr">3039 </span>  <span class="Conceal">¦</span><span class="Constant"> .g         .</span>
 <span id="L3040" class="LineNr">3040 </span>  ]
 <span id="L3041" class="LineNr">3041 </span>  <span class="Comment"># scroll up</span>
 <span id="L3042" class="LineNr">3042 </span>  assume-console [
-<span id="L3043" class="LineNr">3043 </span>    press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
+<span id="L3043" class="LineNr">3043 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
 <span id="L3044" class="LineNr">3044 </span>  ]
 <span id="L3045" class="LineNr">3045 </span>  run [
-<span id="L3046" class="LineNr">3046 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L3046" class="LineNr">3046 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L3047" class="LineNr">3047 </span>  ]
 <span id="L3048" class="LineNr">3048 </span>  <span class="Comment"># screen shows second page</span>
 <span id="L3049" class="LineNr">3049 </span>  screen-should-contain [
-<span id="L3050" class="LineNr">3050 </span>   <span class="Constant"> .          .</span>
-<span id="L3051" class="LineNr">3051 </span>   <span class="Constant"> .c         .</span>
-<span id="L3052" class="LineNr">3052 </span>   <span class="Constant"> .d         .</span>
-<span id="L3053" class="LineNr">3053 </span>   <span class="Constant"> .e         .</span>
+<span id="L3050" class="LineNr">3050 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L3051" class="LineNr">3051 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
+<span id="L3052" class="LineNr">3052 </span>  <span class="Conceal">¦</span><span class="Constant"> .d         .</span>
+<span id="L3053" class="LineNr">3053 </span>  <span class="Conceal">¦</span><span class="Constant"> .e         .</span>
 <span id="L3054" class="LineNr">3054 </span>  ]
 <span id="L3055" class="LineNr">3055 </span>  <span class="Comment"># scroll up again</span>
 <span id="L3056" class="LineNr">3056 </span>  assume-console [
-<span id="L3057" class="LineNr">3057 </span>    press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
+<span id="L3057" class="LineNr">3057 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
 <span id="L3058" class="LineNr">3058 </span>  ]
 <span id="L3059" class="LineNr">3059 </span>  run [
-<span id="L3060" class="LineNr">3060 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L3060" class="LineNr">3060 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L3061" class="LineNr">3061 </span>  ]
 <span id="L3062" class="LineNr">3062 </span>  <span class="Comment"># screen shows original page again</span>
 <span id="L3063" class="LineNr">3063 </span>  screen-should-contain [
-<span id="L3064" class="LineNr">3064 </span>   <span class="Constant"> .          .</span>
-<span id="L3065" class="LineNr">3065 </span>   <span class="Constant"> .a         .</span>
-<span id="L3066" class="LineNr">3066 </span>   <span class="Constant"> .b         .</span>
-<span id="L3067" class="LineNr">3067 </span>   <span class="Constant"> .c         .</span>
+<span id="L3064" class="LineNr">3064 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L3065" class="LineNr">3065 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L3066" class="LineNr">3066 </span>  <span class="Conceal">¦</span><span class="Constant"> .b         .</span>
+<span id="L3067" class="LineNr">3067 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
 <span id="L3068" class="LineNr">3068 </span>  ]
 <span id="L3069" class="LineNr">3069 </span>]
 <span id="L3070" class="LineNr">3070 </span>
@@ -3148,46 +3149,46 @@ if ('onhashchange' in window) {
 <span id="L3088" class="LineNr">3088 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L3089" class="LineNr">3089 </span>  <span class="Comment"># some part of last line is not displayed</span>
 <span id="L3090" class="LineNr">3090 </span>  screen-should-contain [
-<span id="L3091" class="LineNr">3091 </span>   <span class="Constant"> .          .</span>
-<span id="L3092" class="LineNr">3092 </span>   <span class="Constant"> .a         .</span>
-<span id="L3093" class="LineNr">3093 </span>   <span class="Constant"> .b         .</span>
-<span id="L3094" class="LineNr">3094 </span>   <span class="Constant"> .cde↩      .</span>
-<span id="L3095" class="LineNr">3095 </span>   <span class="Constant"> .fgh       .</span>
-<span id="L3096" class="LineNr">3096 </span>   <span class="Constant"> .i         .</span>
+<span id="L3091" class="LineNr">3091 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L3092" class="LineNr">3092 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L3093" class="LineNr">3093 </span>  <span class="Conceal">¦</span><span class="Constant"> .b         .</span>
+<span id="L3094" class="LineNr">3094 </span>  <span class="Conceal">¦</span><span class="Constant"> .cde↩      .</span>
+<span id="L3095" class="LineNr">3095 </span>  <span class="Conceal">¦</span><span class="Constant"> .fgh       .</span>
+<span id="L3096" class="LineNr">3096 </span>  <span class="Conceal">¦</span><span class="Constant"> .i         .</span>
 <span id="L3097" class="LineNr">3097 </span>  ]
 <span id="L3098" class="LineNr">3098 </span>  <span class="Comment"># scroll down a page and a line</span>
 <span id="L3099" class="LineNr">3099 </span>  assume-console [
-<span id="L3100" class="LineNr">3100 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
-<span id="L3101" class="LineNr">3101 </span>    left-click<span class="Constant"> 5</span>,<span class="Constant"> 0</span>
-<span id="L3102" class="LineNr">3102 </span>    press down-arrow
+<span id="L3100" class="LineNr">3100 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L3101" class="LineNr">3101 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 5</span>,<span class="Constant"> 0</span>
+<span id="L3102" class="LineNr">3102 </span>  <span class="Conceal">¦</span> press down-arrow
 <span id="L3103" class="LineNr">3103 </span>  ]
 <span id="L3104" class="LineNr">3104 </span>  run [
-<span id="L3105" class="LineNr">3105 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L3105" class="LineNr">3105 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L3106" class="LineNr">3106 </span>  ]
 <span id="L3107" class="LineNr">3107 </span>  <span class="Comment"># screen shows entire wrapped line</span>
 <span id="L3108" class="LineNr">3108 </span>  screen-should-contain [
-<span id="L3109" class="LineNr">3109 </span>   <span class="Constant"> .          .</span>
-<span id="L3110" class="LineNr">3110 </span>   <span class="Constant"> .j         .</span>
-<span id="L3111" class="LineNr">3111 </span>   <span class="Constant"> .k         .</span>
-<span id="L3112" class="LineNr">3112 </span>   <span class="Constant"> .l         .</span>
-<span id="L3113" class="LineNr">3113 </span>   <span class="Constant"> .m         .</span>
-<span id="L3114" class="LineNr">3114 </span>   <span class="Constant"> .n         .</span>
+<span id="L3109" class="LineNr">3109 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L3110" class="LineNr">3110 </span>  <span class="Conceal">¦</span><span class="Constant"> .j         .</span>
+<span id="L3111" class="LineNr">3111 </span>  <span class="Conceal">¦</span><span class="Constant"> .k         .</span>
+<span id="L3112" class="LineNr">3112 </span>  <span class="Conceal">¦</span><span class="Constant"> .l         .</span>
+<span id="L3113" class="LineNr">3113 </span>  <span class="Conceal">¦</span><span class="Constant"> .m         .</span>
+<span id="L3114" class="LineNr">3114 </span>  <span class="Conceal">¦</span><span class="Constant"> .n         .</span>
 <span id="L3115" class="LineNr">3115 </span>  ]
 <span id="L3116" class="LineNr">3116 </span>  <span class="Comment"># now scroll up one page</span>
 <span id="L3117" class="LineNr">3117 </span>  assume-console [
-<span id="L3118" class="LineNr">3118 </span>    press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
+<span id="L3118" class="LineNr">3118 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
 <span id="L3119" class="LineNr">3119 </span>  ]
 <span id="L3120" class="LineNr">3120 </span>  run [
-<span id="L3121" class="LineNr">3121 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L3121" class="LineNr">3121 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L3122" class="LineNr">3122 </span>  ]
 <span id="L3123" class="LineNr">3123 </span>  <span class="Comment"># screen resets</span>
 <span id="L3124" class="LineNr">3124 </span>  screen-should-contain [
-<span id="L3125" class="LineNr">3125 </span>   <span class="Constant"> .          .</span>
-<span id="L3126" class="LineNr">3126 </span>   <span class="Constant"> .b         .</span>
-<span id="L3127" class="LineNr">3127 </span>   <span class="Constant"> .cde↩      .</span>
-<span id="L3128" class="LineNr">3128 </span>   <span class="Constant"> .fgh       .</span>
-<span id="L3129" class="LineNr">3129 </span>   <span class="Constant"> .i         .</span>
-<span id="L3130" class="LineNr">3130 </span>   <span class="Constant"> .j         .</span>
+<span id="L3125" class="LineNr">3125 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L3126" class="LineNr">3126 </span>  <span class="Conceal">¦</span><span class="Constant"> .b         .</span>
+<span id="L3127" class="LineNr">3127 </span>  <span class="Conceal">¦</span><span class="Constant"> .cde↩      .</span>
+<span id="L3128" class="LineNr">3128 </span>  <span class="Conceal">¦</span><span class="Constant"> .fgh       .</span>
+<span id="L3129" class="LineNr">3129 </span>  <span class="Conceal">¦</span><span class="Constant"> .i         .</span>
+<span id="L3130" class="LineNr">3130 </span>  <span class="Conceal">¦</span><span class="Constant"> .j         .</span>
 <span id="L3131" class="LineNr">3131 </span>  ]
 <span id="L3132" class="LineNr">3132 </span>]
 <span id="L3133" class="LineNr">3133 </span>
@@ -3203,38 +3204,38 @@ if ('onhashchange' in window) {
 <span id="L3143" class="LineNr">3143 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L3144" class="LineNr">3144 </span>  <span class="Comment"># some part of last line is not displayed</span>
 <span id="L3145" class="LineNr">3145 </span>  screen-should-contain [
-<span id="L3146" class="LineNr">3146 </span>   <span class="Constant"> .          .</span>
-<span id="L3147" class="LineNr">3147 </span>   <span class="Constant"> .a         .</span>
-<span id="L3148" class="LineNr">3148 </span>   <span class="Constant"> .bcd↩      .</span>
-<span id="L3149" class="LineNr">3149 </span>   <span class="Constant"> .efg↩      .</span>
+<span id="L3146" class="LineNr">3146 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L3147" class="LineNr">3147 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L3148" class="LineNr">3148 </span>  <span class="Conceal">¦</span><span class="Constant"> .bcd↩      .</span>
+<span id="L3149" class="LineNr">3149 </span>  <span class="Conceal">¦</span><span class="Constant"> .efg↩      .</span>
 <span id="L3150" class="LineNr">3150 </span>  ]
 <span id="L3151" class="LineNr">3151 </span>  <span class="Comment"># scroll down</span>
 <span id="L3152" class="LineNr">3152 </span>  assume-console [
-<span id="L3153" class="LineNr">3153 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L3153" class="LineNr">3153 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L3154" class="LineNr">3154 </span>  ]
 <span id="L3155" class="LineNr">3155 </span>  run [
-<span id="L3156" class="LineNr">3156 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L3156" class="LineNr">3156 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L3157" class="LineNr">3157 </span>  ]
 <span id="L3158" class="LineNr">3158 </span>  <span class="Comment"># screen shows entire wrapped line</span>
 <span id="L3159" class="LineNr">3159 </span>  screen-should-contain [
-<span id="L3160" class="LineNr">3160 </span>   <span class="Constant"> .          .</span>
-<span id="L3161" class="LineNr">3161 </span>   <span class="Constant"> .bcd↩      .</span>
-<span id="L3162" class="LineNr">3162 </span>   <span class="Constant"> .efg↩      .</span>
-<span id="L3163" class="LineNr">3163 </span>   <span class="Constant"> .h         .</span>
+<span id="L3160" class="LineNr">3160 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L3161" class="LineNr">3161 </span>  <span class="Conceal">¦</span><span class="Constant"> .bcd↩      .</span>
+<span id="L3162" class="LineNr">3162 </span>  <span class="Conceal">¦</span><span class="Constant"> .efg↩      .</span>
+<span id="L3163" class="LineNr">3163 </span>  <span class="Conceal">¦</span><span class="Constant"> .h         .</span>
 <span id="L3164" class="LineNr">3164 </span>  ]
 <span id="L3165" class="LineNr">3165 </span>  <span class="Comment"># scroll back up</span>
 <span id="L3166" class="LineNr">3166 </span>  assume-console [
-<span id="L3167" class="LineNr">3167 </span>    press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
+<span id="L3167" class="LineNr">3167 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
 <span id="L3168" class="LineNr">3168 </span>  ]
 <span id="L3169" class="LineNr">3169 </span>  run [
-<span id="L3170" class="LineNr">3170 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L3170" class="LineNr">3170 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L3171" class="LineNr">3171 </span>  ]
 <span id="L3172" class="LineNr">3172 </span>  <span class="Comment"># screen resets</span>
 <span id="L3173" class="LineNr">3173 </span>  screen-should-contain [
-<span id="L3174" class="LineNr">3174 </span>   <span class="Constant"> .          .</span>
-<span id="L3175" class="LineNr">3175 </span>   <span class="Constant"> .a         .</span>
-<span id="L3176" class="LineNr">3176 </span>   <span class="Constant"> .bcd↩      .</span>
-<span id="L3177" class="LineNr">3177 </span>   <span class="Constant"> .efg↩      .</span>
+<span id="L3174" class="LineNr">3174 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L3175" class="LineNr">3175 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L3176" class="LineNr">3176 </span>  <span class="Conceal">¦</span><span class="Constant"> .bcd↩      .</span>
+<span id="L3177" class="LineNr">3177 </span>  <span class="Conceal">¦</span><span class="Constant"> .efg↩      .</span>
 <span id="L3178" class="LineNr">3178 </span>  ]
 <span id="L3179" class="LineNr">3179 </span>]
 <span id="L3180" class="LineNr">3180 </span>
@@ -3254,47 +3255,47 @@ if ('onhashchange' in window) {
 <span id="L3194" class="LineNr">3194 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">4/right</span>
 <span id="L3195" class="LineNr">3195 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L3196" class="LineNr">3196 </span>  screen-should-contain [
-<span id="L3197" class="LineNr">3197 </span>   <span class="Constant"> .          .</span>
-<span id="L3198" class="LineNr">3198 </span>   <span class="Constant"> .axx       .</span>
-<span id="L3199" class="LineNr">3199 </span>   <span class="Constant"> .bxx       .</span>
-<span id="L3200" class="LineNr">3200 </span>   <span class="Constant"> .cxx       .</span>
+<span id="L3197" class="LineNr">3197 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L3198" class="LineNr">3198 </span>  <span class="Conceal">¦</span><span class="Constant"> .axx       .</span>
+<span id="L3199" class="LineNr">3199 </span>  <span class="Conceal">¦</span><span class="Constant"> .bxx       .</span>
+<span id="L3200" class="LineNr">3200 </span>  <span class="Conceal">¦</span><span class="Constant"> .cxx       .</span>
 <span id="L3201" class="LineNr">3201 </span>  ]
 <span id="L3202" class="LineNr">3202 </span>  assume-console [
-<span id="L3203" class="LineNr">3203 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L3203" class="LineNr">3203 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L3204" class="LineNr">3204 </span>  ]
 <span id="L3205" class="LineNr">3205 </span>  run [
-<span id="L3206" class="LineNr">3206 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L3206" class="LineNr">3206 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L3207" class="LineNr">3207 </span>  ]
 <span id="L3208" class="LineNr">3208 </span>  screen-should-contain [
-<span id="L3209" class="LineNr">3209 </span>   <span class="Constant"> .          .</span>
-<span id="L3210" class="LineNr">3210 </span>   <span class="Constant"> .cxx       .</span>
-<span id="L3211" class="LineNr">3211 </span>   <span class="Constant"> .dxx       .</span>
-<span id="L3212" class="LineNr">3212 </span>   <span class="Constant"> .exx       .</span>
+<span id="L3209" class="LineNr">3209 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L3210" class="LineNr">3210 </span>  <span class="Conceal">¦</span><span class="Constant"> .cxx       .</span>
+<span id="L3211" class="LineNr">3211 </span>  <span class="Conceal">¦</span><span class="Constant"> .dxx       .</span>
+<span id="L3212" class="LineNr">3212 </span>  <span class="Conceal">¦</span><span class="Constant"> .exx       .</span>
 <span id="L3213" class="LineNr">3213 </span>  ]
 <span id="L3214" class="LineNr">3214 </span>  assume-console [
-<span id="L3215" class="LineNr">3215 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L3215" class="LineNr">3215 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L3216" class="LineNr">3216 </span>  ]
 <span id="L3217" class="LineNr">3217 </span>  run [
-<span id="L3218" class="LineNr">3218 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L3218" class="LineNr">3218 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L3219" class="LineNr">3219 </span>  ]
 <span id="L3220" class="LineNr">3220 </span>  screen-should-contain [
-<span id="L3221" class="LineNr">3221 </span>   <span class="Constant"> .          .</span>
-<span id="L3222" class="LineNr">3222 </span>   <span class="Constant"> .exx       .</span>
-<span id="L3223" class="LineNr">3223 </span>   <span class="Constant"> .fxx       .</span>
-<span id="L3224" class="LineNr">3224 </span>   <span class="Constant"> .gxx       .</span>
+<span id="L3221" class="LineNr">3221 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L3222" class="LineNr">3222 </span>  <span class="Conceal">¦</span><span class="Constant"> .exx       .</span>
+<span id="L3223" class="LineNr">3223 </span>  <span class="Conceal">¦</span><span class="Constant"> .fxx       .</span>
+<span id="L3224" class="LineNr">3224 </span>  <span class="Conceal">¦</span><span class="Constant"> .gxx       .</span>
 <span id="L3225" class="LineNr">3225 </span>  ]
 <span id="L3226" class="LineNr">3226 </span>  <span class="Comment"># scroll back up past empty line</span>
 <span id="L3227" class="LineNr">3227 </span>  assume-console [
-<span id="L3228" class="LineNr">3228 </span>    press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
+<span id="L3228" class="LineNr">3228 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
 <span id="L3229" class="LineNr">3229 </span>  ]
 <span id="L3230" class="LineNr">3230 </span>  run [
-<span id="L3231" class="LineNr">3231 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L3231" class="LineNr">3231 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L3232" class="LineNr">3232 </span>  ]
 <span id="L3233" class="LineNr">3233 </span>  screen-should-contain [
-<span id="L3234" class="LineNr">3234 </span>   <span class="Constant"> .          .</span>
-<span id="L3235" class="LineNr">3235 </span>   <span class="Constant"> .cxx       .</span>
-<span id="L3236" class="LineNr">3236 </span>   <span class="Constant"> .dxx       .</span>
-<span id="L3237" class="LineNr">3237 </span>   <span class="Constant"> .exx       .</span>
+<span id="L3234" class="LineNr">3234 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L3235" class="LineNr">3235 </span>  <span class="Conceal">¦</span><span class="Constant"> .cxx       .</span>
+<span id="L3236" class="LineNr">3236 </span>  <span class="Conceal">¦</span><span class="Constant"> .dxx       .</span>
+<span id="L3237" class="LineNr">3237 </span>  <span class="Conceal">¦</span><span class="Constant"> .exx       .</span>
 <span id="L3238" class="LineNr">3238 </span>  ]
 <span id="L3239" class="LineNr">3239 </span>]
 <span id="L3240" class="LineNr">3240 </span>
@@ -3314,47 +3315,47 @@ if ('onhashchange' in window) {
 <span id="L3254" class="LineNr">3254 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">4/right</span>
 <span id="L3255" class="LineNr">3255 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L3256" class="LineNr">3256 </span>  screen-should-contain [
-<span id="L3257" class="LineNr">3257 </span>   <span class="Constant"> .          .</span>
-<span id="L3258" class="LineNr">3258 </span>   <span class="Constant"> .axy       .</span>
-<span id="L3259" class="LineNr">3259 </span>   <span class="Constant"> .bxy       .</span>
-<span id="L3260" class="LineNr">3260 </span>   <span class="Constant"> .cxy       .</span>
+<span id="L3257" class="LineNr">3257 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L3258" class="LineNr">3258 </span>  <span class="Conceal">¦</span><span class="Constant"> .axy       .</span>
+<span id="L3259" class="LineNr">3259 </span>  <span class="Conceal">¦</span><span class="Constant"> .bxy       .</span>
+<span id="L3260" class="LineNr">3260 </span>  <span class="Conceal">¦</span><span class="Constant"> .cxy       .</span>
 <span id="L3261" class="LineNr">3261 </span>  ]
 <span id="L3262" class="LineNr">3262 </span>  assume-console [
-<span id="L3263" class="LineNr">3263 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L3263" class="LineNr">3263 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L3264" class="LineNr">3264 </span>  ]
 <span id="L3265" class="LineNr">3265 </span>  run [
-<span id="L3266" class="LineNr">3266 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L3266" class="LineNr">3266 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L3267" class="LineNr">3267 </span>  ]
 <span id="L3268" class="LineNr">3268 </span>  screen-should-contain [
-<span id="L3269" class="LineNr">3269 </span>   <span class="Constant"> .          .</span>
-<span id="L3270" class="LineNr">3270 </span>   <span class="Constant"> .cxy       .</span>
-<span id="L3271" class="LineNr">3271 </span>   <span class="Constant"> .          .</span>
-<span id="L3272" class="LineNr">3272 </span>   <span class="Constant"> .dxy       .</span>
+<span id="L3269" class="LineNr">3269 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L3270" class="LineNr">3270 </span>  <span class="Conceal">¦</span><span class="Constant"> .cxy       .</span>
+<span id="L3271" class="LineNr">3271 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L3272" class="LineNr">3272 </span>  <span class="Conceal">¦</span><span class="Constant"> .dxy       .</span>
 <span id="L3273" class="LineNr">3273 </span>  ]
 <span id="L3274" class="LineNr">3274 </span>  assume-console [
-<span id="L3275" class="LineNr">3275 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L3275" class="LineNr">3275 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L3276" class="LineNr">3276 </span>  ]
 <span id="L3277" class="LineNr">3277 </span>  run [
-<span id="L3278" class="LineNr">3278 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L3278" class="LineNr">3278 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L3279" class="LineNr">3279 </span>  ]
 <span id="L3280" class="LineNr">3280 </span>  screen-should-contain [
-<span id="L3281" class="LineNr">3281 </span>   <span class="Constant"> .          .</span>
-<span id="L3282" class="LineNr">3282 </span>   <span class="Constant"> .dxy       .</span>
-<span id="L3283" class="LineNr">3283 </span>   <span class="Constant"> .exy       .</span>
-<span id="L3284" class="LineNr">3284 </span>   <span class="Constant"> .fxy       .</span>
+<span id="L3281" class="LineNr">3281 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L3282" class="LineNr">3282 </span>  <span class="Conceal">¦</span><span class="Constant"> .dxy       .</span>
+<span id="L3283" class="LineNr">3283 </span>  <span class="Conceal">¦</span><span class="Constant"> .exy       .</span>
+<span id="L3284" class="LineNr">3284 </span>  <span class="Conceal">¦</span><span class="Constant"> .fxy       .</span>
 <span id="L3285" class="LineNr">3285 </span>  ]
 <span id="L3286" class="LineNr">3286 </span>  <span class="Comment"># scroll back up past empty line</span>
 <span id="L3287" class="LineNr">3287 </span>  assume-console [
-<span id="L3288" class="LineNr">3288 </span>    press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
+<span id="L3288" class="LineNr">3288 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
 <span id="L3289" class="LineNr">3289 </span>  ]
 <span id="L3290" class="LineNr">3290 </span>  run [
-<span id="L3291" class="LineNr">3291 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L3291" class="LineNr">3291 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L3292" class="LineNr">3292 </span>  ]
 <span id="L3293" class="LineNr">3293 </span>  screen-should-contain [
-<span id="L3294" class="LineNr">3294 </span>   <span class="Constant"> .          .</span>
-<span id="L3295" class="LineNr">3295 </span>   <span class="Constant"> .cxy       .</span>
-<span id="L3296" class="LineNr">3296 </span>   <span class="Constant"> .          .</span>
-<span id="L3297" class="LineNr">3297 </span>   <span class="Constant"> .dxy       .</span>
+<span id="L3294" class="LineNr">3294 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L3295" class="LineNr">3295 </span>  <span class="Conceal">¦</span><span class="Constant"> .cxy       .</span>
+<span id="L3296" class="LineNr">3296 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L3297" class="LineNr">3297 </span>  <span class="Conceal">¦</span><span class="Constant"> .dxy       .</span>
 <span id="L3298" class="LineNr">3298 </span>  ]
 <span id="L3299" class="LineNr">3299 </span>]
 </pre>
diff --git a/html/edit/004-programming-environment.mu.html b/html/edit/004-programming-environment.mu.html
index 86601105..350af5ac 100644
--- a/html/edit/004-programming-environment.mu.html
+++ b/html/edit/004-programming-environment.mu.html
@@ -15,16 +15,17 @@ body { font-size: 12pt; font-family: monospace; color: #eeeeee; background-color
 a { text-decoration: none; }
 a:hover { text-decoration: underline; }
 * { font-size: 12pt; font-size: 1em; }
-.muData { color: #ffff00; }
-.muControl { color: #c0a020; }
+.muRecipe { color: #ff8700; }
+.muScenario { color: #00af00; }
 .Special { color: #c00000; }
+.Conceal { color: #4e4e4e; }
 .Delimiter { color: #800080; }
 .SalientComment { color: #00ffff; }
 .Constant { color: #00a0a0; }
 .LineNr { color: #444444; }
 .Comment { color: #9090ff; }
-.muRecipe { color: #ff8700; }
-.muScenario { color: #00af00; }
+.muControl { color: #c0a020; }
+.muData { color: #ffff00; }
 -->
 </style>
 
@@ -108,128 +109,128 @@ if ('onhashchange' in window) {
 <span id="L47" class="LineNr"> 47 </span>  <span class="Comment"># todo: test this</span>
 <span id="L48" class="LineNr"> 48 </span>  render-all-on-no-more-events?:bool <span class="Special">&lt;-</span> copy <span class="Constant">0/false</span>
 <span id="L49" class="LineNr"> 49 </span>  <span class="Delimiter">{</span>
-<span id="L50" class="LineNr"> 50 </span>    <span class="Comment"># looping over each (keyboard or touch) event as it occurs</span>
-<span id="L51" class="LineNr"> 51 </span><span class="Constant">    +next-event</span>
-<span id="L52" class="LineNr"> 52 </span>    e:<a href='../084console.mu.html#L4'>event</a>, found?:bool, quit?:bool, <a href='../084console.mu.html#L23'>console</a> <span class="Special">&lt;-</span> <a href='../084console.mu.html#L35'>read-event</a> <a href='../084console.mu.html#L23'>console</a>
-<span id="L53" class="LineNr"> 53 </span>    <span class="muControl">loop-unless</span> found?
-<span id="L54" class="LineNr"> 54 </span>    <span class="muControl">break-if</span> quit?  <span class="Comment"># only in tests</span>
-<span id="L55" class="LineNr"> 55 </span>    trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[next-event]</span>
-<span id="L56" class="LineNr"> 56 </span><span class="Constant">    <a href='004-programming-environment.mu.html#L56'>&lt;handle-event&gt;</a></span>
-<span id="L57" class="LineNr"> 57 </span>    <span class="Comment"># check for global events that will trigger regardless of which editor has focus</span>
-<span id="L58" class="LineNr"> 58 </span>    <span class="Delimiter">{</span>
-<span id="L59" class="LineNr"> 59 </span>      k:num, is-keycode?:bool <span class="Special">&lt;-</span> maybe-convert e:<a href='../084console.mu.html#L4'>event</a>, <span class="Constant">keycode:variant</span>
-<span id="L60" class="LineNr"> 60 </span>      <span class="muControl">break-unless</span> is-keycode?
-<span id="L61" class="LineNr"> 61 </span><span class="Constant">      <a href='004-programming-environment.mu.html#L61'>&lt;global-keypress&gt;</a></span>
-<span id="L62" class="LineNr"> 62 </span>    <span class="Delimiter">}</span>
-<span id="L63" class="LineNr"> 63 </span>    <span class="Delimiter">{</span>
-<span id="L64" class="LineNr"> 64 </span>      c:char, is-unicode?:bool <span class="Special">&lt;-</span> maybe-convert e:<a href='../084console.mu.html#L4'>event</a>, <span class="Constant">text:variant</span>
-<span id="L65" class="LineNr"> 65 </span>      <span class="muControl">break-unless</span> is-unicode?
-<span id="L66" class="LineNr"> 66 </span><span class="Constant">      <a href='004-programming-environment.mu.html#L66'>&lt;global-type&gt;</a></span>
-<span id="L67" class="LineNr"> 67 </span>    <span class="Delimiter">}</span>
-<span id="L68" class="LineNr"> 68 </span>    <span class="Comment"># 'touch' event - send to both sides, see what picks it up</span>
-<span id="L69" class="LineNr"> 69 </span>    <span class="Delimiter">{</span>
-<span id="L70" class="LineNr"> 70 </span>      t:<a href='../084console.mu.html#L12'>touch-event</a>, is-touch?:bool <span class="Special">&lt;-</span> maybe-convert e:<a href='../084console.mu.html#L4'>event</a>, <span class="Constant">touch:variant</span>
-<span id="L71" class="LineNr"> 71 </span>      <span class="muControl">break-unless</span> is-touch?
-<span id="L72" class="LineNr"> 72 </span>      <span class="Comment"># ignore all but 'left-click' events for now</span>
-<span id="L73" class="LineNr"> 73 </span>      <span class="Comment"># todo: test this</span>
-<span id="L74" class="LineNr"> 74 </span>      touch-type:num <span class="Special">&lt;-</span> get t, <span class="Constant">type:offset</span>
-<span id="L75" class="LineNr"> 75 </span>      is-left-click?:bool <span class="Special">&lt;-</span> equal touch-type, <span class="Constant">65513/mouse-left</span>
-<span id="L76" class="LineNr"> 76 </span>      <span class="muControl">loop-unless</span> is-left-click?, <span class="Constant">+next-event</span>
-<span id="L77" class="LineNr"> 77 </span>      click-row:num <span class="Special">&lt;-</span> get t, <span class="Constant">row:offset</span>
-<span id="L78" class="LineNr"> 78 </span>      click-column:num <span class="Special">&lt;-</span> get t, <span class="Constant">column:offset</span>
-<span id="L79" class="LineNr"> 79 </span>      <span class="Comment"># later exceptions for non-editor touches will go here</span>
-<span id="L80" class="LineNr"> 80 </span><span class="Constant">      <a href='004-programming-environment.mu.html#L80'>&lt;global-touch&gt;</a></span>
-<span id="L81" class="LineNr"> 81 </span>      <span class="Comment"># send to both editors</span>
-<span id="L82" class="LineNr"> 82 </span>      _ <span class="Special">&lt;-</span> <a href='002-typing.mu.html#L48'>move-cursor-in-editor</a> <a href='../081print.mu.html#L4'>screen</a>, recipes, t
-<span id="L83" class="LineNr"> 83 </span>      sandbox-in-focus?:bool <span class="Special">&lt;-</span> <a href='002-typing.mu.html#L48'>move-cursor-in-editor</a> <a href='../081print.mu.html#L4'>screen</a>, current-sandbox, t
-<span id="L84" class="LineNr"> 84 </span>      *env <span class="Special">&lt;-</span> put *env, <span class="Constant">sandbox-in-focus?:offset</span>, sandbox-in-focus?
-<span id="L85" class="LineNr"> 85 </span>      <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L511'>update-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, recipes, current-sandbox, sandbox-in-focus?, env
-<span id="L86" class="LineNr"> 86 </span>      <span class="muControl">loop</span> <span class="Constant">+next-event</span>
-<span id="L87" class="LineNr"> 87 </span>    <span class="Delimiter">}</span>
-<span id="L88" class="LineNr"> 88 </span>    <span class="Comment"># 'resize' event - redraw editor</span>
-<span id="L89" class="LineNr"> 89 </span>    <span class="Comment"># todo: test this after supporting resize in assume-console</span>
-<span id="L90" class="LineNr"> 90 </span>    <span class="Delimiter">{</span>
-<span id="L91" class="LineNr"> 91 </span>      r:<a href='../084console.mu.html#L18'>resize-event</a>, is-resize?:bool <span class="Special">&lt;-</span> maybe-convert e:<a href='../084console.mu.html#L4'>event</a>, <span class="Constant"><a href='004-programming-environment.mu.html#L175'>resize</a>:variant</span>
-<span id="L92" class="LineNr"> 92 </span>      <span class="muControl">break-unless</span> is-resize?
-<span id="L93" class="LineNr"> 93 </span>      <span class="Comment"># if more events, we're still resizing; wait until we stop</span>
-<span id="L94" class="LineNr"> 94 </span>      more-events?:bool <span class="Special">&lt;-</span> <a href='../084console.mu.html#L100'>has-more-events?</a> <a href='../084console.mu.html#L23'>console</a>
-<span id="L95" class="LineNr"> 95 </span>      <span class="Delimiter">{</span>
-<span id="L96" class="LineNr"> 96 </span>        <span class="muControl">break-unless</span> more-events?
-<span id="L97" class="LineNr"> 97 </span>        render-all-on-no-more-events? <span class="Special">&lt;-</span> copy <span class="Constant">1/true</span>  <span class="Comment"># no rendering now, full rendering on some future event</span>
-<span id="L98" class="LineNr"> 98 </span>      <span class="Delimiter">}</span>
-<span id="L99" class="LineNr"> 99 </span>      <span class="Delimiter">{</span>
-<span id="L100" class="LineNr">100 </span>        <span class="muControl">break-if</span> more-events?
-<span id="L101" class="LineNr">101 </span>        env, <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L175'>resize</a> <a href='../081print.mu.html#L4'>screen</a>, env
-<span id="L102" class="LineNr">102 </span>        <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='004-programming-environment.mu.html#L202'>render-without-moving-cursor</a>
-<span id="L103" class="LineNr">103 </span>        render-all-on-no-more-events? <span class="Special">&lt;-</span> copy <span class="Constant">0/false</span>  <span class="Comment"># full render done</span>
-<span id="L104" class="LineNr">104 </span>      <span class="Delimiter">}</span>
-<span id="L105" class="LineNr">105 </span>      <span class="muControl">loop</span> <span class="Constant">+next-event</span>
-<span id="L106" class="LineNr">106 </span>    <span class="Delimiter">}</span>
-<span id="L107" class="LineNr">107 </span>    <span class="Comment"># if it's not global and not a touch event, send to appropriate editor</span>
-<span id="L108" class="LineNr">108 </span>    <span class="Delimiter">{</span>
-<span id="L109" class="LineNr">109 </span>      <a href='../081print.mu.html#L623'>hide-screen</a> <a href='../081print.mu.html#L4'>screen</a>
-<span id="L110" class="LineNr">110 </span>      sandbox-in-focus?:bool <span class="Special">&lt;-</span> get *env, <span class="Constant">sandbox-in-focus?:offset</span>
-<span id="L111" class="LineNr">111 </span>      <span class="Delimiter">{</span>
-<span id="L112" class="LineNr">112 </span>        <span class="muControl">break-if</span> sandbox-in-focus?
-<span id="L113" class="LineNr">113 </span>        render?:bool <span class="Special">&lt;-</span> <a href='002-typing.mu.html#L164'>handle-keyboard-event</a> <a href='../081print.mu.html#L4'>screen</a>, recipes, e:<a href='../084console.mu.html#L4'>event</a>
-<span id="L114" class="LineNr">114 </span>        <span class="Comment"># refresh screen only if no more events</span>
-<span id="L115" class="LineNr">115 </span>        <span class="Comment"># if there are more events to process, wait for them to clear up, then make sure you render-all afterward.</span>
-<span id="L116" class="LineNr">116 </span>        more-events?:bool <span class="Special">&lt;-</span> <a href='../084console.mu.html#L100'>has-more-events?</a> <a href='../084console.mu.html#L23'>console</a>
-<span id="L117" class="LineNr">117 </span>        <span class="Delimiter">{</span>
-<span id="L118" class="LineNr">118 </span>          <span class="muControl">break-unless</span> more-events?
-<span id="L119" class="LineNr">119 </span>          render-all-on-no-more-events? <span class="Special">&lt;-</span> copy <span class="Constant">1/true</span>  <span class="Comment"># no rendering now, full rendering on some future event</span>
-<span id="L120" class="LineNr">120 </span>          <span class="muControl">jump</span> <span class="Constant">+finish-event</span>
-<span id="L121" class="LineNr">121 </span>        <span class="Delimiter">}</span>
-<span id="L122" class="LineNr">122 </span>        <span class="Delimiter">{</span>
-<span id="L123" class="LineNr">123 </span>          <span class="muControl">break-if</span> more-events?
-<span id="L124" class="LineNr">124 </span>          <span class="Delimiter">{</span>
-<span id="L125" class="LineNr">125 </span>            <span class="muControl">break-unless</span> render-all-on-no-more-events?
-<span id="L126" class="LineNr">126 </span>            <span class="Comment"># no more events, and we have to force render</span>
-<span id="L127" class="LineNr">127 </span>            <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
-<span id="L128" class="LineNr">128 </span>            render-all-on-no-more-events? <span class="Special">&lt;-</span> copy <span class="Constant">0/false</span>
-<span id="L129" class="LineNr">129 </span>            <span class="muControl">jump</span> <span class="Constant">+finish-event</span>
-<span id="L130" class="LineNr">130 </span>          <span class="Delimiter">}</span>
-<span id="L131" class="LineNr">131 </span>          <span class="Comment"># no more events, no force render</span>
-<span id="L132" class="LineNr">132 </span>          <span class="Delimiter">{</span>
-<span id="L133" class="LineNr">133 </span>            <span class="muControl">break-unless</span> render?
-<span id="L134" class="LineNr">134 </span>            <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L477'>render-recipes</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
-<span id="L135" class="LineNr">135 </span>            <span class="muControl">jump</span> <span class="Constant">+finish-event</span>
-<span id="L136" class="LineNr">136 </span>          <span class="Delimiter">}</span>
-<span id="L137" class="LineNr">137 </span>        <span class="Delimiter">}</span>
-<span id="L138" class="LineNr">138 </span>      <span class="Delimiter">}</span>
-<span id="L139" class="LineNr">139 </span>      <span class="Delimiter">{</span>
-<span id="L140" class="LineNr">140 </span>        <span class="muControl">break-unless</span> sandbox-in-focus?
-<span id="L141" class="LineNr">141 </span>        render?:bool <span class="Special">&lt;-</span> <a href='002-typing.mu.html#L164'>handle-keyboard-event</a> <a href='../081print.mu.html#L4'>screen</a>, current-sandbox, e:<a href='../084console.mu.html#L4'>event</a>
-<span id="L142" class="LineNr">142 </span>        <span class="Comment"># refresh screen only if no more events</span>
-<span id="L143" class="LineNr">143 </span>        <span class="Comment"># if there are more events to process, wait for them to clear up, then make sure you render-all afterward.</span>
-<span id="L144" class="LineNr">144 </span>        more-events?:bool <span class="Special">&lt;-</span> <a href='../084console.mu.html#L100'>has-more-events?</a> <a href='../084console.mu.html#L23'>console</a>
-<span id="L145" class="LineNr">145 </span>        <span class="Delimiter">{</span>
-<span id="L146" class="LineNr">146 </span>          <span class="muControl">break-unless</span> more-events?
-<span id="L147" class="LineNr">147 </span>          render-all-on-no-more-events? <span class="Special">&lt;-</span> copy <span class="Constant">1/true</span>  <span class="Comment"># no rendering now, full rendering on some future event</span>
-<span id="L148" class="LineNr">148 </span>          <span class="muControl">jump</span> <span class="Constant">+finish-event</span>
-<span id="L149" class="LineNr">149 </span>        <span class="Delimiter">}</span>
-<span id="L150" class="LineNr">150 </span>        <span class="Delimiter">{</span>
-<span id="L151" class="LineNr">151 </span>          <span class="muControl">break-if</span> more-events?
-<span id="L152" class="LineNr">152 </span>          <span class="Delimiter">{</span>
-<span id="L153" class="LineNr">153 </span>            <span class="muControl">break-unless</span> render-all-on-no-more-events?
-<span id="L154" class="LineNr">154 </span>            <span class="Comment"># no more events, and we have to force render</span>
-<span id="L155" class="LineNr">155 </span>            <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
-<span id="L156" class="LineNr">156 </span>            render-all-on-no-more-events? <span class="Special">&lt;-</span> copy <span class="Constant">0/false</span>
-<span id="L157" class="LineNr">157 </span>            <span class="muControl">jump</span> <span class="Constant">+finish-event</span>
-<span id="L158" class="LineNr">158 </span>          <span class="Delimiter">}</span>
-<span id="L159" class="LineNr">159 </span>          <span class="Comment"># no more events, no force render</span>
-<span id="L160" class="LineNr">160 </span>          <span class="Delimiter">{</span>
-<span id="L161" class="LineNr">161 </span>            <span class="muControl">break-unless</span> render?
-<span id="L162" class="LineNr">162 </span>            <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> render-sandbox-side <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
-<span id="L163" class="LineNr">163 </span>            <span class="muControl">jump</span> <span class="Constant">+finish-event</span>
-<span id="L164" class="LineNr">164 </span>          <span class="Delimiter">}</span>
-<span id="L165" class="LineNr">165 </span>        <span class="Delimiter">}</span>
-<span id="L166" class="LineNr">166 </span>      <span class="Delimiter">}</span>
-<span id="L167" class="LineNr">167 </span><span class="Constant">      +finish-event</span>
-<span id="L168" class="LineNr">168 </span>      <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L511'>update-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, recipes, current-sandbox, sandbox-in-focus?, env
-<span id="L169" class="LineNr">169 </span>      <a href='../081print.mu.html#L631'>show-screen</a> <a href='../081print.mu.html#L4'>screen</a>
-<span id="L170" class="LineNr">170 </span>    <span class="Delimiter">}</span>
-<span id="L171" class="LineNr">171 </span>    <span class="muControl">loop</span>
+<span id="L50" class="LineNr"> 50 </span>  <span class="Conceal">¦</span> <span class="Comment"># looping over each (keyboard or touch) event as it occurs</span>
+<span id="L51" class="LineNr"> 51 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> +next-event</span>
+<span id="L52" class="LineNr"> 52 </span>  <span class="Conceal">¦</span> e:<a href='../084console.mu.html#L4'>event</a>, found?:bool, quit?:bool, <a href='../084console.mu.html#L23'>console</a> <span class="Special">&lt;-</span> <a href='../084console.mu.html#L35'>read-event</a> <a href='../084console.mu.html#L23'>console</a>
+<span id="L53" class="LineNr"> 53 </span>  <span class="Conceal">¦</span> <span class="muControl">loop-unless</span> found?
+<span id="L54" class="LineNr"> 54 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> quit?  <span class="Comment"># only in tests</span>
+<span id="L55" class="LineNr"> 55 </span>  <span class="Conceal">¦</span> trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[next-event]</span>
+<span id="L56" class="LineNr"> 56 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> <a href='004-programming-environment.mu.html#L56'>&lt;handle-event&gt;</a></span>
+<span id="L57" class="LineNr"> 57 </span>  <span class="Conceal">¦</span> <span class="Comment"># check for global events that will trigger regardless of which editor has focus</span>
+<span id="L58" class="LineNr"> 58 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L59" class="LineNr"> 59 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> k:num, is-keycode?:bool <span class="Special">&lt;-</span> maybe-convert e:<a href='../084console.mu.html#L4'>event</a>, <span class="Constant">keycode:variant</span>
+<span id="L60" class="LineNr"> 60 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-keycode?
+<span id="L61" class="LineNr"> 61 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> <a href='004-programming-environment.mu.html#L61'>&lt;global-keypress&gt;</a></span>
+<span id="L62" class="LineNr"> 62 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L63" class="LineNr"> 63 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L64" class="LineNr"> 64 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> c:char, is-unicode?:bool <span class="Special">&lt;-</span> maybe-convert e:<a href='../084console.mu.html#L4'>event</a>, <span class="Constant">text:variant</span>
+<span id="L65" class="LineNr"> 65 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-unicode?
+<span id="L66" class="LineNr"> 66 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> <a href='004-programming-environment.mu.html#L66'>&lt;global-type&gt;</a></span>
+<span id="L67" class="LineNr"> 67 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L68" class="LineNr"> 68 </span>  <span class="Conceal">¦</span> <span class="Comment"># 'touch' event - send to both sides, see what picks it up</span>
+<span id="L69" class="LineNr"> 69 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L70" class="LineNr"> 70 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> t:<a href='../084console.mu.html#L12'>touch-event</a>, is-touch?:bool <span class="Special">&lt;-</span> maybe-convert e:<a href='../084console.mu.html#L4'>event</a>, <span class="Constant">touch:variant</span>
+<span id="L71" class="LineNr"> 71 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-touch?
+<span id="L72" class="LineNr"> 72 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># ignore all but 'left-click' events for now</span>
+<span id="L73" class="LineNr"> 73 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># todo: test this</span>
+<span id="L74" class="LineNr"> 74 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> touch-type:num <span class="Special">&lt;-</span> get t, <span class="Constant">type:offset</span>
+<span id="L75" class="LineNr"> 75 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> is-left-click?:bool <span class="Special">&lt;-</span> equal touch-type, <span class="Constant">65513/mouse-left</span>
+<span id="L76" class="LineNr"> 76 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop-unless</span> is-left-click?, <span class="Constant">+next-event</span>
+<span id="L77" class="LineNr"> 77 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> click-row:num <span class="Special">&lt;-</span> get t, <span class="Constant">row:offset</span>
+<span id="L78" class="LineNr"> 78 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> click-column:num <span class="Special">&lt;-</span> get t, <span class="Constant">column:offset</span>
+<span id="L79" class="LineNr"> 79 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># later exceptions for non-editor touches will go here</span>
+<span id="L80" class="LineNr"> 80 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> <a href='004-programming-environment.mu.html#L80'>&lt;global-touch&gt;</a></span>
+<span id="L81" class="LineNr"> 81 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># send to both editors</span>
+<span id="L82" class="LineNr"> 82 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> _ <span class="Special">&lt;-</span> <a href='002-typing.mu.html#L48'>move-cursor-in-editor</a> <a href='../081print.mu.html#L4'>screen</a>, recipes, t
+<span id="L83" class="LineNr"> 83 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> sandbox-in-focus?:bool <span class="Special">&lt;-</span> <a href='002-typing.mu.html#L48'>move-cursor-in-editor</a> <a href='../081print.mu.html#L4'>screen</a>, current-sandbox, t
+<span id="L84" class="LineNr"> 84 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> *env <span class="Special">&lt;-</span> put *env, <span class="Constant">sandbox-in-focus?:offset</span>, sandbox-in-focus?
+<span id="L85" class="LineNr"> 85 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L511'>update-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, recipes, current-sandbox, sandbox-in-focus?, env
+<span id="L86" class="LineNr"> 86 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-event</span>
+<span id="L87" class="LineNr"> 87 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L88" class="LineNr"> 88 </span>  <span class="Conceal">¦</span> <span class="Comment"># 'resize' event - redraw editor</span>
+<span id="L89" class="LineNr"> 89 </span>  <span class="Conceal">¦</span> <span class="Comment"># todo: test this after supporting resize in assume-console</span>
+<span id="L90" class="LineNr"> 90 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L91" class="LineNr"> 91 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> r:<a href='../084console.mu.html#L18'>resize-event</a>, is-resize?:bool <span class="Special">&lt;-</span> maybe-convert e:<a href='../084console.mu.html#L4'>event</a>, <span class="Constant"><a href='004-programming-environment.mu.html#L175'>resize</a>:variant</span>
+<span id="L92" class="LineNr"> 92 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-resize?
+<span id="L93" class="LineNr"> 93 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># if more events, we're still resizing; wait until we stop</span>
+<span id="L94" class="LineNr"> 94 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> more-events?:bool <span class="Special">&lt;-</span> <a href='../084console.mu.html#L100'>has-more-events?</a> <a href='../084console.mu.html#L23'>console</a>
+<span id="L95" class="LineNr"> 95 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L96" class="LineNr"> 96 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> more-events?
+<span id="L97" class="LineNr"> 97 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> render-all-on-no-more-events? <span class="Special">&lt;-</span> copy <span class="Constant">1/true</span>  <span class="Comment"># no rendering now, full rendering on some future event</span>
+<span id="L98" class="LineNr"> 98 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L99" class="LineNr"> 99 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L100" class="LineNr">100 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> more-events?
+<span id="L101" class="LineNr">101 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> env, <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L175'>resize</a> <a href='../081print.mu.html#L4'>screen</a>, env
+<span id="L102" class="LineNr">102 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='004-programming-environment.mu.html#L202'>render-without-moving-cursor</a>
+<span id="L103" class="LineNr">103 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> render-all-on-no-more-events? <span class="Special">&lt;-</span> copy <span class="Constant">0/false</span>  <span class="Comment"># full render done</span>
+<span id="L104" class="LineNr">104 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L105" class="LineNr">105 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-event</span>
+<span id="L106" class="LineNr">106 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L107" class="LineNr">107 </span>  <span class="Conceal">¦</span> <span class="Comment"># if it's not global and not a touch event, send to appropriate editor</span>
+<span id="L108" class="LineNr">108 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L109" class="LineNr">109 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../081print.mu.html#L623'>hide-screen</a> <a href='../081print.mu.html#L4'>screen</a>
+<span id="L110" class="LineNr">110 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> sandbox-in-focus?:bool <span class="Special">&lt;-</span> get *env, <span class="Constant">sandbox-in-focus?:offset</span>
+<span id="L111" class="LineNr">111 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L112" class="LineNr">112 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> sandbox-in-focus?
+<span id="L113" class="LineNr">113 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> render?:bool <span class="Special">&lt;-</span> <a href='002-typing.mu.html#L164'>handle-keyboard-event</a> <a href='../081print.mu.html#L4'>screen</a>, recipes, e:<a href='../084console.mu.html#L4'>event</a>
+<span id="L114" class="LineNr">114 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># refresh screen only if no more events</span>
+<span id="L115" class="LineNr">115 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># if there are more events to process, wait for them to clear up, then make sure you render-all afterward.</span>
+<span id="L116" class="LineNr">116 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> more-events?:bool <span class="Special">&lt;-</span> <a href='../084console.mu.html#L100'>has-more-events?</a> <a href='../084console.mu.html#L23'>console</a>
+<span id="L117" class="LineNr">117 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L118" class="LineNr">118 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> more-events?
+<span id="L119" class="LineNr">119 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> render-all-on-no-more-events? <span class="Special">&lt;-</span> copy <span class="Constant">1/true</span>  <span class="Comment"># no rendering now, full rendering on some future event</span>
+<span id="L120" class="LineNr">120 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">jump</span> <span class="Constant">+finish-event</span>
+<span id="L121" class="LineNr">121 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L122" class="LineNr">122 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L123" class="LineNr">123 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> more-events?
+<span id="L124" class="LineNr">124 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L125" class="LineNr">125 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> render-all-on-no-more-events?
+<span id="L126" class="LineNr">126 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># no more events, and we have to force render</span>
+<span id="L127" class="LineNr">127 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
+<span id="L128" class="LineNr">128 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> render-all-on-no-more-events? <span class="Special">&lt;-</span> copy <span class="Constant">0/false</span>
+<span id="L129" class="LineNr">129 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">jump</span> <span class="Constant">+finish-event</span>
+<span id="L130" class="LineNr">130 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L131" class="LineNr">131 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># no more events, no force render</span>
+<span id="L132" class="LineNr">132 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L133" class="LineNr">133 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> render?
+<span id="L134" class="LineNr">134 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L477'>render-recipes</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
+<span id="L135" class="LineNr">135 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">jump</span> <span class="Constant">+finish-event</span>
+<span id="L136" class="LineNr">136 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L137" class="LineNr">137 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L138" class="LineNr">138 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L139" class="LineNr">139 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L140" class="LineNr">140 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> sandbox-in-focus?
+<span id="L141" class="LineNr">141 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> render?:bool <span class="Special">&lt;-</span> <a href='002-typing.mu.html#L164'>handle-keyboard-event</a> <a href='../081print.mu.html#L4'>screen</a>, current-sandbox, e:<a href='../084console.mu.html#L4'>event</a>
+<span id="L142" class="LineNr">142 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># refresh screen only if no more events</span>
+<span id="L143" class="LineNr">143 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># if there are more events to process, wait for them to clear up, then make sure you render-all afterward.</span>
+<span id="L144" class="LineNr">144 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> more-events?:bool <span class="Special">&lt;-</span> <a href='../084console.mu.html#L100'>has-more-events?</a> <a href='../084console.mu.html#L23'>console</a>
+<span id="L145" class="LineNr">145 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L146" class="LineNr">146 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> more-events?
+<span id="L147" class="LineNr">147 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> render-all-on-no-more-events? <span class="Special">&lt;-</span> copy <span class="Constant">1/true</span>  <span class="Comment"># no rendering now, full rendering on some future event</span>
+<span id="L148" class="LineNr">148 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">jump</span> <span class="Constant">+finish-event</span>
+<span id="L149" class="LineNr">149 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L150" class="LineNr">150 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L151" class="LineNr">151 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> more-events?
+<span id="L152" class="LineNr">152 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L153" class="LineNr">153 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> render-all-on-no-more-events?
+<span id="L154" class="LineNr">154 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># no more events, and we have to force render</span>
+<span id="L155" class="LineNr">155 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
+<span id="L156" class="LineNr">156 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> render-all-on-no-more-events? <span class="Special">&lt;-</span> copy <span class="Constant">0/false</span>
+<span id="L157" class="LineNr">157 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">jump</span> <span class="Constant">+finish-event</span>
+<span id="L158" class="LineNr">158 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L159" class="LineNr">159 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># no more events, no force render</span>
+<span id="L160" class="LineNr">160 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L161" class="LineNr">161 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> render?
+<span id="L162" class="LineNr">162 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> render-sandbox-side <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
+<span id="L163" class="LineNr">163 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">jump</span> <span class="Constant">+finish-event</span>
+<span id="L164" class="LineNr">164 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L165" class="LineNr">165 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L166" class="LineNr">166 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L167" class="LineNr">167 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> +finish-event</span>
+<span id="L168" class="LineNr">168 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L511'>update-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, recipes, current-sandbox, sandbox-in-focus?, env
+<span id="L169" class="LineNr">169 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../081print.mu.html#L631'>show-screen</a> <a href='../081print.mu.html#L4'>screen</a>
+<span id="L170" class="LineNr">170 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L171" class="LineNr">171 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L172" class="LineNr">172 </span>  <span class="Delimiter">}</span>
 <span id="L173" class="LineNr">173 </span>]
 <span id="L174" class="LineNr">174 </span>
@@ -284,55 +285,55 @@ if ('onhashchange' in window) {
 <span id="L223" class="LineNr">223 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, top-of-screen
 <span id="L224" class="LineNr">224 </span>  <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, column
 <span id="L225" class="LineNr">225 </span>  <span class="Delimiter">{</span>
-<span id="L226" class="LineNr">226 </span><span class="Constant">    +next-character</span>
-<span id="L227" class="LineNr">227 </span>    <span class="muControl">break-unless</span> curr
-<span id="L228" class="LineNr">228 </span>    off-screen?:bool <span class="Special">&lt;-</span> greater-or-equal row, <a href='../081print.mu.html#L594'>screen-height</a>
-<span id="L229" class="LineNr">229 </span>    <span class="muControl">break-if</span> off-screen?
-<span id="L230" class="LineNr">230 </span>    <span class="Comment"># if we find old-before-cursor still on the new resized screen, update</span>
-<span id="L231" class="LineNr">231 </span>    <span class="Comment"># editor.cursor-row and editor.cursor-column based on</span>
-<span id="L232" class="LineNr">232 </span>    <span class="Comment"># old-before-cursor</span>
-<span id="L233" class="LineNr">233 </span>    <span class="Delimiter">{</span>
-<span id="L234" class="LineNr">234 </span>      at-cursor?:bool <span class="Special">&lt;-</span> equal old-before-cursor, <a href='../065duplex_list.mu.html#L36'>prev</a>
-<span id="L235" class="LineNr">235 </span>      <span class="muControl">break-unless</span> at-cursor?
-<span id="L236" class="LineNr">236 </span>      *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, row
-<span id="L237" class="LineNr">237 </span>      *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, column
-<span id="L238" class="LineNr">238 </span>      *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, old-before-cursor
-<span id="L239" class="LineNr">239 </span>    <span class="Delimiter">}</span>
-<span id="L240" class="LineNr">240 </span>    c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
-<span id="L241" class="LineNr">241 </span><span class="Constant">    &lt;character-c-received&gt;</span>
-<span id="L242" class="LineNr">242 </span>    <span class="Delimiter">{</span>
-<span id="L243" class="LineNr">243 </span>      <span class="Comment"># newline? move to left rather than 0</span>
-<span id="L244" class="LineNr">244 </span>      newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
-<span id="L245" class="LineNr">245 </span>      <span class="muControl">break-unless</span> newline?
-<span id="L246" class="LineNr">246 </span>      <span class="Comment"># clear rest of line in this window</span>
-<span id="L247" class="LineNr">247 </span>      <a href='../081print.mu.html#L408'>clear-line-until</a> <a href='../081print.mu.html#L4'>screen</a>, right
-<span id="L248" class="LineNr">248 </span>      <span class="Comment"># skip to next line</span>
-<span id="L249" class="LineNr">249 </span>      row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
-<span id="L250" class="LineNr">250 </span>      column <span class="Special">&lt;-</span> copy left
-<span id="L251" class="LineNr">251 </span>      <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, column
-<span id="L252" class="LineNr">252 </span>      curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
-<span id="L253" class="LineNr">253 </span>      <a href='../065duplex_list.mu.html#L36'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> <a href='../065duplex_list.mu.html#L36'>prev</a>
-<span id="L254" class="LineNr">254 </span>      <span class="muControl">loop</span> <span class="Constant">+next-character</span>
-<span id="L255" class="LineNr">255 </span>    <span class="Delimiter">}</span>
-<span id="L256" class="LineNr">256 </span>    <span class="Delimiter">{</span>
-<span id="L257" class="LineNr">257 </span>      <span class="Comment"># at right? wrap. even if there's only one more letter left; we need</span>
-<span id="L258" class="LineNr">258 </span>      <span class="Comment"># room for clicking on the cursor after it.</span>
-<span id="L259" class="LineNr">259 </span>      at-right?:bool <span class="Special">&lt;-</span> equal column, right
-<span id="L260" class="LineNr">260 </span>      <span class="muControl">break-unless</span> at-right?
-<span id="L261" class="LineNr">261 </span>      <span class="Comment"># print wrap icon</span>
-<span id="L262" class="LineNr">262 </span>      wrap-icon:char <span class="Special">&lt;-</span> copy <span class="Constant">8617/loop-back-to-left</span>
-<span id="L263" class="LineNr">263 </span>      print <a href='../081print.mu.html#L4'>screen</a>, wrap-icon, <span class="Constant">245/grey</span>
-<span id="L264" class="LineNr">264 </span>      column <span class="Special">&lt;-</span> copy left
-<span id="L265" class="LineNr">265 </span>      row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
-<span id="L266" class="LineNr">266 </span>      <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, column
-<span id="L267" class="LineNr">267 </span>      <span class="Comment"># don't increment curr</span>
-<span id="L268" class="LineNr">268 </span>      <span class="muControl">loop</span> <span class="Constant">+next-character</span>
-<span id="L269" class="LineNr">269 </span>    <span class="Delimiter">}</span>
-<span id="L270" class="LineNr">270 </span>    print <a href='../081print.mu.html#L4'>screen</a>, c, color
-<span id="L271" class="LineNr">271 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
-<span id="L272" class="LineNr">272 </span>    <a href='../065duplex_list.mu.html#L36'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> <a href='../065duplex_list.mu.html#L36'>prev</a>
-<span id="L273" class="LineNr">273 </span>    column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
-<span id="L274" class="LineNr">274 </span>    <span class="muControl">loop</span>
+<span id="L226" class="LineNr">226 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> +next-character</span>
+<span id="L227" class="LineNr">227 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> curr
+<span id="L228" class="LineNr">228 </span>  <span class="Conceal">¦</span> off-screen?:bool <span class="Special">&lt;-</span> greater-or-equal row, <a href='../081print.mu.html#L594'>screen-height</a>
+<span id="L229" class="LineNr">229 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> off-screen?
+<span id="L230" class="LineNr">230 </span>  <span class="Conceal">¦</span> <span class="Comment"># if we find old-before-cursor still on the new resized screen, update</span>
+<span id="L231" class="LineNr">231 </span>  <span class="Conceal">¦</span> <span class="Comment"># editor.cursor-row and editor.cursor-column based on</span>
+<span id="L232" class="LineNr">232 </span>  <span class="Conceal">¦</span> <span class="Comment"># old-before-cursor</span>
+<span id="L233" class="LineNr">233 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L234" class="LineNr">234 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-cursor?:bool <span class="Special">&lt;-</span> equal old-before-cursor, <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L235" class="LineNr">235 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-cursor?
+<span id="L236" class="LineNr">236 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, row
+<span id="L237" class="LineNr">237 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, column
+<span id="L238" class="LineNr">238 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, old-before-cursor
+<span id="L239" class="LineNr">239 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L240" class="LineNr">240 </span>  <span class="Conceal">¦</span> c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
+<span id="L241" class="LineNr">241 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;character-c-received&gt;</span>
+<span id="L242" class="LineNr">242 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L243" class="LineNr">243 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># newline? move to left rather than 0</span>
+<span id="L244" class="LineNr">244 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
+<span id="L245" class="LineNr">245 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> newline?
+<span id="L246" class="LineNr">246 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># clear rest of line in this window</span>
+<span id="L247" class="LineNr">247 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../081print.mu.html#L408'>clear-line-until</a> <a href='../081print.mu.html#L4'>screen</a>, right
+<span id="L248" class="LineNr">248 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># skip to next line</span>
+<span id="L249" class="LineNr">249 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
+<span id="L250" class="LineNr">250 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> copy left
+<span id="L251" class="LineNr">251 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, column
+<span id="L252" class="LineNr">252 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L253" class="LineNr">253 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L254" class="LineNr">254 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-character</span>
+<span id="L255" class="LineNr">255 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L256" class="LineNr">256 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L257" class="LineNr">257 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># at right? wrap. even if there's only one more letter left; we need</span>
+<span id="L258" class="LineNr">258 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># room for clicking on the cursor after it.</span>
+<span id="L259" class="LineNr">259 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-right?:bool <span class="Special">&lt;-</span> equal column, right
+<span id="L260" class="LineNr">260 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-right?
+<span id="L261" class="LineNr">261 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># print wrap icon</span>
+<span id="L262" class="LineNr">262 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> wrap-icon:char <span class="Special">&lt;-</span> copy <span class="Constant">8617/loop-back-to-left</span>
+<span id="L263" class="LineNr">263 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, wrap-icon, <span class="Constant">245/grey</span>
+<span id="L264" class="LineNr">264 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> copy left
+<span id="L265" class="LineNr">265 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
+<span id="L266" class="LineNr">266 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, column
+<span id="L267" class="LineNr">267 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># don't increment curr</span>
+<span id="L268" class="LineNr">268 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-character</span>
+<span id="L269" class="LineNr">269 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L270" class="LineNr">270 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, c, color
+<span id="L271" class="LineNr">271 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L272" class="LineNr">272 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L273" class="LineNr">273 </span>  <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
+<span id="L274" class="LineNr">274 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L275" class="LineNr">275 </span>  <span class="Delimiter">}</span>
 <span id="L276" class="LineNr">276 </span>  <span class="Comment"># save first character off-screen</span>
 <span id="L277" class="LineNr">277 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">bottom-of-screen:offset</span>, curr
@@ -346,27 +347,27 @@ if ('onhashchange' in window) {
 <span id="L285" class="LineNr">285 </span>  assume-screen <span class="Constant">30/width</span>, <span class="Constant">5/height</span>
 <span id="L286" class="LineNr">286 </span>  <span class="Comment"># initialize both halves of screen</span>
 <span id="L287" class="LineNr">287 </span>  assume-resources [
-<span id="L288" class="LineNr">288 </span>    <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
-<span id="L289" class="LineNr">289 </span><span class="Constant">      |abc|</span>
-<span id="L290" class="LineNr">290 </span>    ]
+<span id="L288" class="LineNr">288 </span>  <span class="Conceal">¦</span> <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
+<span id="L289" class="LineNr">289 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |abc|</span>
+<span id="L290" class="LineNr">290 </span>  <span class="Conceal">¦</span> ]
 <span id="L291" class="LineNr">291 </span>  ]
 <span id="L292" class="LineNr">292 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[def]</span>  <span class="Comment"># contents of sandbox editor</span>
 <span id="L293" class="LineNr">293 </span>  <span class="Comment"># focus on both sides</span>
 <span id="L294" class="LineNr">294 </span>  assume-console [
-<span id="L295" class="LineNr">295 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
-<span id="L296" class="LineNr">296 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 17</span>
+<span id="L295" class="LineNr">295 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
+<span id="L296" class="LineNr">296 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 17</span>
 <span id="L297" class="LineNr">297 </span>  ]
 <span id="L298" class="LineNr">298 </span>  <span class="Comment"># check cursor column in each</span>
 <span id="L299" class="LineNr">299 </span>  run [
-<span id="L300" class="LineNr">300 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
-<span id="L301" class="LineNr">301 </span>    recipes:&amp;:editor <span class="Special">&lt;-</span> get *env, <span class="Constant">recipes:offset</span>
-<span id="L302" class="LineNr">302 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *recipes, <span class="Constant">cursor-column:offset</span>
-<span id="L303" class="LineNr">303 </span>    sandbox:&amp;:editor <span class="Special">&lt;-</span> get *env, <span class="Constant">current-sandbox:offset</span>
-<span id="L304" class="LineNr">304 </span>    7:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">cursor-column:offset</span>
+<span id="L300" class="LineNr">300 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L301" class="LineNr">301 </span>  <span class="Conceal">¦</span> recipes:&amp;:editor <span class="Special">&lt;-</span> get *env, <span class="Constant">recipes:offset</span>
+<span id="L302" class="LineNr">302 </span>  <span class="Conceal">¦</span> 5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *recipes, <span class="Constant">cursor-column:offset</span>
+<span id="L303" class="LineNr">303 </span>  <span class="Conceal">¦</span> sandbox:&amp;:editor <span class="Special">&lt;-</span> get *env, <span class="Constant">current-sandbox:offset</span>
+<span id="L304" class="LineNr">304 </span>  <span class="Conceal">¦</span> 7:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">cursor-column:offset</span>
 <span id="L305" class="LineNr">305 </span>  ]
 <span id="L306" class="LineNr">306 </span>  memory-should-contain [
-<span id="L307" class="LineNr">307 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L308" class="LineNr">308 </span>   <span class="Constant"> 7</span> <span class="Special">&lt;-</span><span class="Constant"> 17</span>
+<span id="L307" class="LineNr">307 </span>  <span class="Conceal">¦</span><span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L308" class="LineNr">308 </span>  <span class="Conceal">¦</span><span class="Constant"> 7</span> <span class="Special">&lt;-</span><span class="Constant"> 17</span>
 <span id="L309" class="LineNr">309 </span>  ]
 <span id="L310" class="LineNr">310 </span>]
 <span id="L311" class="LineNr">311 </span>
@@ -376,48 +377,48 @@ if ('onhashchange' in window) {
 <span id="L315" class="LineNr">315 </span>  assume-screen <span class="Constant">30/width</span>, <span class="Constant">5/height</span>
 <span id="L316" class="LineNr">316 </span>  <span class="Comment"># initialize both halves of screen</span>
 <span id="L317" class="LineNr">317 </span>  assume-resources [
-<span id="L318" class="LineNr">318 </span>    <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
-<span id="L319" class="LineNr">319 </span><span class="Constant">      |abc|</span>
-<span id="L320" class="LineNr">320 </span>    ]
+<span id="L318" class="LineNr">318 </span>  <span class="Conceal">¦</span> <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
+<span id="L319" class="LineNr">319 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |abc|</span>
+<span id="L320" class="LineNr">320 </span>  <span class="Conceal">¦</span> ]
 <span id="L321" class="LineNr">321 </span>  ]
 <span id="L322" class="LineNr">322 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[def]</span>  <span class="Comment"># contents of sandbox</span>
 <span id="L323" class="LineNr">323 </span>  <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
 <span id="L324" class="LineNr">324 </span>  <span class="Comment"># type one letter in each of them</span>
 <span id="L325" class="LineNr">325 </span>  assume-console [
-<span id="L326" class="LineNr">326 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
-<span id="L327" class="LineNr">327 </span>    type <span class="Constant">[0]</span>
-<span id="L328" class="LineNr">328 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 17</span>
-<span id="L329" class="LineNr">329 </span>    type <span class="Constant">[1]</span>
+<span id="L326" class="LineNr">326 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
+<span id="L327" class="LineNr">327 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
+<span id="L328" class="LineNr">328 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 17</span>
+<span id="L329" class="LineNr">329 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
 <span id="L330" class="LineNr">330 </span>  ]
 <span id="L331" class="LineNr">331 </span>  run [
-<span id="L332" class="LineNr">332 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
-<span id="L333" class="LineNr">333 </span>    recipes:&amp;:editor <span class="Special">&lt;-</span> get *env, <span class="Constant">recipes:offset</span>
-<span id="L334" class="LineNr">334 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *recipes, <span class="Constant">cursor-column:offset</span>
-<span id="L335" class="LineNr">335 </span>    sandbox:&amp;:editor <span class="Special">&lt;-</span> get *env, <span class="Constant">current-sandbox:offset</span>
-<span id="L336" class="LineNr">336 </span>    7:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">cursor-column:offset</span>
+<span id="L332" class="LineNr">332 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L333" class="LineNr">333 </span>  <span class="Conceal">¦</span> recipes:&amp;:editor <span class="Special">&lt;-</span> get *env, <span class="Constant">recipes:offset</span>
+<span id="L334" class="LineNr">334 </span>  <span class="Conceal">¦</span> 5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *recipes, <span class="Constant">cursor-column:offset</span>
+<span id="L335" class="LineNr">335 </span>  <span class="Conceal">¦</span> sandbox:&amp;:editor <span class="Special">&lt;-</span> get *env, <span class="Constant">current-sandbox:offset</span>
+<span id="L336" class="LineNr">336 </span>  <span class="Conceal">¦</span> 7:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">cursor-column:offset</span>
 <span id="L337" class="LineNr">337 </span>  ]
 <span id="L338" class="LineNr">338 </span>  screen-should-contain [
-<span id="L339" class="LineNr">339 </span>   <span class="Constant"> .           run (F4)           .  # this line has a different background, but we don't test that yet</span>
-<span id="L340" class="LineNr">340 </span>   <span class="Constant"> .a0bc           ╎d1ef          .</span>
-<span id="L341" class="LineNr">341 </span>   <span class="Constant"> .               ╎──────────────.</span>
-<span id="L342" class="LineNr">342 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎              .</span>
-<span id="L343" class="LineNr">343 </span>   <span class="Constant"> .               ╎              .</span>
+<span id="L339" class="LineNr">339 </span>  <span class="Conceal">¦</span><span class="Constant"> .           run (F4)           .  # this line has a different background, but we don't test that yet</span>
+<span id="L340" class="LineNr">340 </span>  <span class="Conceal">¦</span><span class="Constant"> .a0bc           ╎d1ef          .</span>
+<span id="L341" class="LineNr">341 </span>  <span class="Conceal">¦</span><span class="Constant"> .               ╎──────────────.</span>
+<span id="L342" class="LineNr">342 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎              .</span>
+<span id="L343" class="LineNr">343 </span>  <span class="Conceal">¦</span><span class="Constant"> .               ╎              .</span>
 <span id="L344" class="LineNr">344 </span>  ]
 <span id="L345" class="LineNr">345 </span>  memory-should-contain [
-<span id="L346" class="LineNr">346 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>  <span class="Comment"># cursor column of recipe editor</span>
-<span id="L347" class="LineNr">347 </span>   <span class="Constant"> 7</span> <span class="Special">&lt;-</span><span class="Constant"> 18</span>  <span class="Comment"># cursor column of sandbox editor</span>
+<span id="L346" class="LineNr">346 </span>  <span class="Conceal">¦</span><span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>  <span class="Comment"># cursor column of recipe editor</span>
+<span id="L347" class="LineNr">347 </span>  <span class="Conceal">¦</span><span class="Constant"> 7</span> <span class="Special">&lt;-</span><span class="Constant"> 18</span>  <span class="Comment"># cursor column of sandbox editor</span>
 <span id="L348" class="LineNr">348 </span>  ]
 <span id="L349" class="LineNr">349 </span>  <span class="Comment"># show the cursor at the right window</span>
 <span id="L350" class="LineNr">350 </span>  run [
-<span id="L351" class="LineNr">351 </span>    cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
-<span id="L352" class="LineNr">352 </span>    print <a href='../081print.mu.html#L4'>screen</a>, cursor
+<span id="L351" class="LineNr">351 </span>  <span class="Conceal">¦</span> cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
+<span id="L352" class="LineNr">352 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, cursor
 <span id="L353" class="LineNr">353 </span>  ]
 <span id="L354" class="LineNr">354 </span>  screen-should-contain [
-<span id="L355" class="LineNr">355 </span>   <span class="Constant"> .           run (F4)           .</span>
-<span id="L356" class="LineNr">356 </span>   <span class="Constant"> .a0bc           ╎d1␣f          .</span>
-<span id="L357" class="LineNr">357 </span>   <span class="Constant"> .               ╎──────────────.</span>
-<span id="L358" class="LineNr">358 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎              .</span>
-<span id="L359" class="LineNr">359 </span>   <span class="Constant"> .               ╎              .</span>
+<span id="L355" class="LineNr">355 </span>  <span class="Conceal">¦</span><span class="Constant"> .           run (F4)           .</span>
+<span id="L356" class="LineNr">356 </span>  <span class="Conceal">¦</span><span class="Constant"> .a0bc           ╎d1␣f          .</span>
+<span id="L357" class="LineNr">357 </span>  <span class="Conceal">¦</span><span class="Constant"> .               ╎──────────────.</span>
+<span id="L358" class="LineNr">358 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎              .</span>
+<span id="L359" class="LineNr">359 </span>  <span class="Conceal">¦</span><span class="Constant"> .               ╎              .</span>
 <span id="L360" class="LineNr">360 </span>  ]
 <span id="L361" class="LineNr">361 </span>]
 <span id="L362" class="LineNr">362 </span>
@@ -426,43 +427,43 @@ if ('onhashchange' in window) {
 <span id="L365" class="LineNr">365 </span>  trace-until <span class="Constant">100/app</span>  <span class="Comment"># trace too long</span>
 <span id="L366" class="LineNr">366 </span>  assume-screen <span class="Constant">30/width</span>, <span class="Constant">5/height</span>
 <span id="L367" class="LineNr">367 </span>  assume-resources [
-<span id="L368" class="LineNr">368 </span>    <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
-<span id="L369" class="LineNr">369 </span><span class="Constant">      |abc|</span>
-<span id="L370" class="LineNr">370 </span>    ]
+<span id="L368" class="LineNr">368 </span>  <span class="Conceal">¦</span> <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
+<span id="L369" class="LineNr">369 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |abc|</span>
+<span id="L370" class="LineNr">370 </span>  <span class="Conceal">¦</span> ]
 <span id="L371" class="LineNr">371 </span>  ]
 <span id="L372" class="LineNr">372 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[def]</span>
 <span id="L373" class="LineNr">373 </span>  <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
 <span id="L374" class="LineNr">374 </span>  <span class="Comment"># initialize programming environment and highlight cursor</span>
 <span id="L375" class="LineNr">375 </span>  assume-console <span class="Constant">[]</span>
 <span id="L376" class="LineNr">376 </span>  run [
-<span id="L377" class="LineNr">377 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
-<span id="L378" class="LineNr">378 </span>    cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
-<span id="L379" class="LineNr">379 </span>    print <a href='../081print.mu.html#L4'>screen</a>, cursor
+<span id="L377" class="LineNr">377 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L378" class="LineNr">378 </span>  <span class="Conceal">¦</span> cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
+<span id="L379" class="LineNr">379 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, cursor
 <span id="L380" class="LineNr">380 </span>  ]
 <span id="L381" class="LineNr">381 </span>  <span class="Comment"># is cursor at the right place?</span>
 <span id="L382" class="LineNr">382 </span>  screen-should-contain [
-<span id="L383" class="LineNr">383 </span>   <span class="Constant"> .           run (F4)           .</span>
-<span id="L384" class="LineNr">384 </span>   <span class="Constant"> .␣bc            ╎def           .</span>
-<span id="L385" class="LineNr">385 </span>   <span class="Constant"> .               ╎──────────────.</span>
-<span id="L386" class="LineNr">386 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎              .</span>
-<span id="L387" class="LineNr">387 </span>   <span class="Constant"> .               ╎              .</span>
+<span id="L383" class="LineNr">383 </span>  <span class="Conceal">¦</span><span class="Constant"> .           run (F4)           .</span>
+<span id="L384" class="LineNr">384 </span>  <span class="Conceal">¦</span><span class="Constant"> .␣bc            ╎def           .</span>
+<span id="L385" class="LineNr">385 </span>  <span class="Conceal">¦</span><span class="Constant"> .               ╎──────────────.</span>
+<span id="L386" class="LineNr">386 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎              .</span>
+<span id="L387" class="LineNr">387 </span>  <span class="Conceal">¦</span><span class="Constant"> .               ╎              .</span>
 <span id="L388" class="LineNr">388 </span>  ]
 <span id="L389" class="LineNr">389 </span>  <span class="Comment"># now try typing a letter</span>
 <span id="L390" class="LineNr">390 </span>  assume-console [
-<span id="L391" class="LineNr">391 </span>    type <span class="Constant">[z]</span>
+<span id="L391" class="LineNr">391 </span>  <span class="Conceal">¦</span> type <span class="Constant">[z]</span>
 <span id="L392" class="LineNr">392 </span>  ]
 <span id="L393" class="LineNr">393 </span>  run [
-<span id="L394" class="LineNr">394 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
-<span id="L395" class="LineNr">395 </span>    cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
-<span id="L396" class="LineNr">396 </span>    print <a href='../081print.mu.html#L4'>screen</a>, cursor
+<span id="L394" class="LineNr">394 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L395" class="LineNr">395 </span>  <span class="Conceal">¦</span> cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
+<span id="L396" class="LineNr">396 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, cursor
 <span id="L397" class="LineNr">397 </span>  ]
 <span id="L398" class="LineNr">398 </span>  <span class="Comment"># cursor should still be right</span>
 <span id="L399" class="LineNr">399 </span>  screen-should-contain [
-<span id="L400" class="LineNr">400 </span>   <span class="Constant"> .           run (F4)           .</span>
-<span id="L401" class="LineNr">401 </span>   <span class="Constant"> .z␣bc           ╎def           .</span>
-<span id="L402" class="LineNr">402 </span>   <span class="Constant"> .               ╎──────────────.</span>
-<span id="L403" class="LineNr">403 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎              .</span>
-<span id="L404" class="LineNr">404 </span>   <span class="Constant"> .               ╎              .</span>
+<span id="L400" class="LineNr">400 </span>  <span class="Conceal">¦</span><span class="Constant"> .           run (F4)           .</span>
+<span id="L401" class="LineNr">401 </span>  <span class="Conceal">¦</span><span class="Constant"> .z␣bc           ╎def           .</span>
+<span id="L402" class="LineNr">402 </span>  <span class="Conceal">¦</span><span class="Constant"> .               ╎──────────────.</span>
+<span id="L403" class="LineNr">403 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎              .</span>
+<span id="L404" class="LineNr">404 </span>  <span class="Conceal">¦</span><span class="Constant"> .               ╎              .</span>
 <span id="L405" class="LineNr">405 </span>  ]
 <span id="L406" class="LineNr">406 </span>]
 <span id="L407" class="LineNr">407 </span>
@@ -478,28 +479,28 @@ if ('onhashchange' in window) {
 <span id="L417" class="LineNr">417 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, test-sandbox-editor-contents
 <span id="L418" class="LineNr">418 </span>  <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
 <span id="L419" class="LineNr">419 </span>  screen-should-contain [
-<span id="L420" class="LineNr">420 </span>   <span class="Constant"> .           run (F4)           .</span>
-<span id="L421" class="LineNr">421 </span>   <span class="Constant"> .               ╎abc           .</span>
-<span id="L422" class="LineNr">422 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎def           .</span>
-<span id="L423" class="LineNr">423 </span>   <span class="Constant"> .               ╎──────────────.</span>
-<span id="L424" class="LineNr">424 </span>   <span class="Constant"> .               ╎              .</span>
+<span id="L420" class="LineNr">420 </span>  <span class="Conceal">¦</span><span class="Constant"> .           run (F4)           .</span>
+<span id="L421" class="LineNr">421 </span>  <span class="Conceal">¦</span><span class="Constant"> .               ╎abc           .</span>
+<span id="L422" class="LineNr">422 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎def           .</span>
+<span id="L423" class="LineNr">423 </span>  <span class="Conceal">¦</span><span class="Constant"> .               ╎──────────────.</span>
+<span id="L424" class="LineNr">424 </span>  <span class="Conceal">¦</span><span class="Constant"> .               ╎              .</span>
 <span id="L425" class="LineNr">425 </span>  ]
 <span id="L426" class="LineNr">426 </span>  <span class="Comment"># position cursor at start of second line and hit backspace</span>
 <span id="L427" class="LineNr">427 </span>  assume-console [
-<span id="L428" class="LineNr">428 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 16</span>
-<span id="L429" class="LineNr">429 </span>    press backspace
+<span id="L428" class="LineNr">428 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 16</span>
+<span id="L429" class="LineNr">429 </span>  <span class="Conceal">¦</span> press backspace
 <span id="L430" class="LineNr">430 </span>  ]
 <span id="L431" class="LineNr">431 </span>  run [
-<span id="L432" class="LineNr">432 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
-<span id="L433" class="LineNr">433 </span>    cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
-<span id="L434" class="LineNr">434 </span>    print <a href='../081print.mu.html#L4'>screen</a>, cursor
+<span id="L432" class="LineNr">432 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L433" class="LineNr">433 </span>  <span class="Conceal">¦</span> cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
+<span id="L434" class="LineNr">434 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, cursor
 <span id="L435" class="LineNr">435 </span>  ]
 <span id="L436" class="LineNr">436 </span>  <span class="Comment"># cursor moves to end of old line</span>
 <span id="L437" class="LineNr">437 </span>  screen-should-contain [
-<span id="L438" class="LineNr">438 </span>   <span class="Constant"> .           run (F4)           .</span>
-<span id="L439" class="LineNr">439 </span>   <span class="Constant"> .               ╎abc␣ef        .</span>
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+<span id="L439" class="LineNr">439 </span>  <span class="Conceal">¦</span><span class="Constant"> .               ╎abc␣ef        .</span>
+<span id="L440" class="LineNr">440 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎──────────────.</span>
+<span id="L441" class="LineNr">441 </span>  <span class="Conceal">¦</span><span class="Constant"> .               ╎              .</span>
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+<span id="L516" class="LineNr">516 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> sandbox-in-focus?
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+<span id="L518" class="LineNr">518 </span>  <span class="Conceal">¦</span> cursor-column:num <span class="Special">&lt;-</span> get *recipes, <span class="Constant">cursor-column:offset</span>
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+<span id="L548" class="LineNr">548 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># at right? wrap.</span>
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-<span id="L613" class="LineNr">613 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L511'>update-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, recipes, current-sandbox, sandbox-in-focus?, env
-<span id="L614" class="LineNr">614 </span>    <span class="muControl">loop</span> <span class="Constant">+next-event</span>
+<span id="L608" class="LineNr">608 </span>  <span class="Conceal">¦</span> switch-side?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">14/ctrl-n</span>
+<span id="L609" class="LineNr">609 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> switch-side?
+<span id="L610" class="LineNr">610 </span>  <span class="Conceal">¦</span> sandbox-in-focus?:bool <span class="Special">&lt;-</span> get *env, <span class="Constant">sandbox-in-focus?:offset</span>
+<span id="L611" class="LineNr">611 </span>  <span class="Conceal">¦</span> sandbox-in-focus? <span class="Special">&lt;-</span> not sandbox-in-focus?
+<span id="L612" class="LineNr">612 </span>  <span class="Conceal">¦</span> *env <span class="Special">&lt;-</span> put *env, <span class="Constant">sandbox-in-focus?:offset</span>, sandbox-in-focus?
+<span id="L613" class="LineNr">613 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L511'>update-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, recipes, current-sandbox, sandbox-in-focus?, env
+<span id="L614" class="LineNr">614 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-event</span>
 <span id="L615" class="LineNr">615 </span>  <span class="Delimiter">}</span>
 <span id="L616" class="LineNr">616 </span>]
 <span id="L617" class="LineNr">617 </span>
@@ -683,22 +684,22 @@ if ('onhashchange' in window) {
 <span id="L622" class="LineNr">622 </span>  <span class="Constant">load-ingredients</span>
 <span id="L623" class="LineNr">623 </span>  style:char, style-found?:bool <span class="Special">&lt;-</span> <span class="Constant">next-ingredient</span>
 <span id="L624" class="LineNr">624 </span>  <span class="Delimiter">{</span>
-<span id="L625" class="LineNr">625 </span>    <span class="muControl">break-if</span> style-found?
-<span id="L626" class="LineNr">626 </span>    style <span class="Special">&lt;-</span> copy <span class="Constant">9474/vertical</span>
+<span id="L625" class="LineNr">625 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> style-found?
+<span id="L626" class="LineNr">626 </span>  <span class="Conceal">¦</span> style <span class="Special">&lt;-</span> copy <span class="Constant">9474/vertical</span>
 <span id="L627" class="LineNr">627 </span>  <span class="Delimiter">}</span>
 <span id="L628" class="LineNr">628 </span>  color:num, color-found?:bool <span class="Special">&lt;-</span> <span class="Constant">next-ingredient</span>
 <span id="L629" class="LineNr">629 </span>  <span class="Delimiter">{</span>
-<span id="L630" class="LineNr">630 </span>    <span class="Comment"># default color to white</span>
-<span id="L631" class="LineNr">631 </span>    <span class="muControl">break-if</span> color-found?
-<span id="L632" class="LineNr">632 </span>    color <span class="Special">&lt;-</span> copy <span class="Constant">245/grey</span>
+<span id="L630" class="LineNr">630 </span>  <span class="Conceal">¦</span> <span class="Comment"># default color to white</span>
+<span id="L631" class="LineNr">631 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> color-found?
+<span id="L632" class="LineNr">632 </span>  <span class="Conceal">¦</span> color <span class="Special">&lt;-</span> copy <span class="Constant">245/grey</span>
 <span id="L633" class="LineNr">633 </span>  <span class="Delimiter">}</span>
 <span id="L634" class="LineNr">634 </span>  <span class="Delimiter">{</span>
-<span id="L635" class="LineNr">635 </span>    continue?:bool <span class="Special">&lt;-</span> lesser-than y, bottom
-<span id="L636" class="LineNr">636 </span>    <span class="muControl">break-unless</span> continue?
-<span id="L637" class="LineNr">637 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, y, col
-<span id="L638" class="LineNr">638 </span>    print <a href='../081print.mu.html#L4'>screen</a>, style, color
-<span id="L639" class="LineNr">639 </span>    y <span class="Special">&lt;-</span> add y,<span class="Constant"> 1</span>
-<span id="L640" class="LineNr">640 </span>    <span class="muControl">loop</span>
+<span id="L635" class="LineNr">635 </span>  <span class="Conceal">¦</span> continue?:bool <span class="Special">&lt;-</span> lesser-than y, bottom
+<span id="L636" class="LineNr">636 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> continue?
+<span id="L637" class="LineNr">637 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, y, col
+<span id="L638" class="LineNr">638 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, style, color
+<span id="L639" class="LineNr">639 </span>  <span class="Conceal">¦</span> y <span class="Special">&lt;-</span> add y,<span class="Constant"> 1</span>
+<span id="L640" class="LineNr">640 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L641" class="LineNr">641 </span>  <span class="Delimiter">}</span>
 <span id="L642" class="LineNr">642 </span>]
 </pre>
diff --git a/html/edit/005-sandbox.mu.html b/html/edit/005-sandbox.mu.html
index e25d4a82..1e77e54e 100644
--- a/html/edit/005-sandbox.mu.html
+++ b/html/edit/005-sandbox.mu.html
@@ -15,16 +15,17 @@ body { font-size: 12pt; font-family: monospace; color: #eeeeee; background-color
 a { text-decoration: none; }
 a:hover { text-decoration: underline; }
 * { font-size: 12pt; font-size: 1em; }
-.muData { color: #ffff00; }
-.muControl { color: #c0a020; }
+.muRecipe { color: #ff8700; }
+.muScenario { color: #00af00; }
 .Special { color: #c00000; }
+.Conceal { color: #4e4e4e; }
 .Delimiter { color: #800080; }
 .SalientComment { color: #00ffff; }
 .Constant { color: #00a0a0; }
 .LineNr { color: #444444; }
 .Comment { color: #9090ff; }
-.muRecipe { color: #ff8700; }
-.muScenario { color: #00af00; }
+.muControl { color: #c0a020; }
+.muData { color: #ffff00; }
 -->
 </style>
 
@@ -110,94 +111,94 @@ if ('onhashchange' in window) {
 <span id="L49" class="LineNr">  49 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[divide-with-remainder 11, 3]</span>
 <span id="L50" class="LineNr">  50 </span>  <span class="Comment"># run the code in the editors</span>
 <span id="L51" class="LineNr">  51 </span>  assume-console [
-<span id="L52" class="LineNr">  52 </span>    press F4
+<span id="L52" class="LineNr">  52 </span>  <span class="Conceal">¦</span> press F4
 <span id="L53" class="LineNr">  53 </span>  ]
 <span id="L54" class="LineNr">  54 </span>  run [
-<span id="L55" class="LineNr">  55 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L55" class="LineNr">  55 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L56" class="LineNr">  56 </span>  ]
 <span id="L57" class="LineNr">  57 </span>  <span class="Comment"># check that screen prints the results</span>
 <span id="L58" class="LineNr">  58 </span>  screen-should-contain [
-<span id="L59" class="LineNr">  59 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L60" class="LineNr">  60 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L61" class="LineNr">  61 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L62" class="LineNr">  62 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L63" class="LineNr">  63 </span>   <span class="Constant"> .                                                  ╎divide-with-remainder 11, 3                      .</span>
-<span id="L64" class="LineNr">  64 </span>   <span class="Constant"> .                                                  ╎3                                                .</span>
-<span id="L65" class="LineNr">  65 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L66" class="LineNr">  66 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L67" class="LineNr">  67 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L59" class="LineNr">  59 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L60" class="LineNr">  60 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L61" class="LineNr">  61 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L62" class="LineNr">  62 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L63" class="LineNr">  63 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎divide-with-remainder 11, 3                      .</span>
+<span id="L64" class="LineNr">  64 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎3                                                .</span>
+<span id="L65" class="LineNr">  65 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L66" class="LineNr">  66 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L67" class="LineNr">  67 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L68" class="LineNr">  68 </span>  ]
 <span id="L69" class="LineNr">  69 </span>  screen-should-contain-in-color <span class="Constant">7/white</span>, [
-<span id="L70" class="LineNr">  70 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L71" class="LineNr">  71 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L72" class="LineNr">  72 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L73" class="LineNr">  73 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L74" class="LineNr">  74 </span>   <span class="Constant"> .                                                   divide-with-remainder 11, 3                      .</span>
-<span id="L75" class="LineNr">  75 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L76" class="LineNr">  76 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L77" class="LineNr">  77 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L78" class="LineNr">  78 </span>   <span class="Constant"> .                                                                                                    .</span>
+<span id="L70" class="LineNr">  70 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L71" class="LineNr">  71 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L72" class="LineNr">  72 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L73" class="LineNr">  73 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L74" class="LineNr">  74 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                   divide-with-remainder 11, 3                      .</span>
+<span id="L75" class="LineNr">  75 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L76" class="LineNr">  76 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L77" class="LineNr">  77 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L78" class="LineNr">  78 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
 <span id="L79" class="LineNr">  79 </span>  ]
 <span id="L80" class="LineNr">  80 </span>  screen-should-contain-in-color <span class="Constant">245/grey</span>, [
-<span id="L81" class="LineNr">  81 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L82" class="LineNr">  82 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L83" class="LineNr">  83 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L84" class="LineNr">  84 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L85" class="LineNr">  85 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L86" class="LineNr">  86 </span>   <span class="Constant"> .                                                  ╎3                                                .</span>
-<span id="L87" class="LineNr">  87 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L88" class="LineNr">  88 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L89" class="LineNr">  89 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L81" class="LineNr">  81 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L82" class="LineNr">  82 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L83" class="LineNr">  83 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L84" class="LineNr">  84 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L85" class="LineNr">  85 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L86" class="LineNr">  86 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎3                                                .</span>
+<span id="L87" class="LineNr">  87 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L88" class="LineNr">  88 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L89" class="LineNr">  89 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L90" class="LineNr">  90 </span>  ]
 <span id="L91" class="LineNr">  91 </span>  <span class="Comment"># sandbox menu in reverse video</span>
 <span id="L92" class="LineNr">  92 </span>  screen-should-contain-in-color <span class="Constant">232/black</span>, [
-<span id="L93" class="LineNr">  93 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L94" class="LineNr">  94 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L95" class="LineNr">  95 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L96" class="LineNr">  96 </span>   <span class="Constant"> .                                                   0   edit          copy            delete         .</span>
+<span id="L93" class="LineNr">  93 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L94" class="LineNr">  94 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L95" class="LineNr">  95 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L96" class="LineNr">  96 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                   0   edit          copy            delete         .</span>
 <span id="L97" class="LineNr">  97 </span>  ]
 <span id="L98" class="LineNr">  98 </span>  <span class="Comment"># run another command</span>
 <span id="L99" class="LineNr">  99 </span>  assume-console [
-<span id="L100" class="LineNr"> 100 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 80</span>
-<span id="L101" class="LineNr"> 101 </span>    type <span class="Constant">[add 2, 2]</span>
-<span id="L102" class="LineNr"> 102 </span>    press F4
+<span id="L100" class="LineNr"> 100 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 80</span>
+<span id="L101" class="LineNr"> 101 </span>  <span class="Conceal">¦</span> type <span class="Constant">[add 2, 2]</span>
+<span id="L102" class="LineNr"> 102 </span>  <span class="Conceal">¦</span> press F4
 <span id="L103" class="LineNr"> 103 </span>  ]
 <span id="L104" class="LineNr"> 104 </span>  run [
-<span id="L105" class="LineNr"> 105 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L105" class="LineNr"> 105 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L106" class="LineNr"> 106 </span>  ]
 <span id="L107" class="LineNr"> 107 </span>  <span class="Comment"># check that screen prints both sandboxes</span>
 <span id="L108" class="LineNr"> 108 </span>  screen-should-contain [
-<span id="L109" class="LineNr"> 109 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L110" class="LineNr"> 110 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L111" class="LineNr"> 111 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L112" class="LineNr"> 112 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L113" class="LineNr"> 113 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L114" class="LineNr"> 114 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
-<span id="L115" class="LineNr"> 115 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L116" class="LineNr"> 116 </span>   <span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
-<span id="L117" class="LineNr"> 117 </span>   <span class="Constant"> .                                                  ╎divide-with-remainder 11, 3                      .</span>
-<span id="L118" class="LineNr"> 118 </span>   <span class="Constant"> .                                                  ╎3                                                .</span>
-<span id="L119" class="LineNr"> 119 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L120" class="LineNr"> 120 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L121" class="LineNr"> 121 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L109" class="LineNr"> 109 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L110" class="LineNr"> 110 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L111" class="LineNr"> 111 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L112" class="LineNr"> 112 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L113" class="LineNr"> 113 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L114" class="LineNr"> 114 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L115" class="LineNr"> 115 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L116" class="LineNr"> 116 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
+<span id="L117" class="LineNr"> 117 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎divide-with-remainder 11, 3                      .</span>
+<span id="L118" class="LineNr"> 118 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎3                                                .</span>
+<span id="L119" class="LineNr"> 119 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L120" class="LineNr"> 120 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L121" class="LineNr"> 121 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L122" class="LineNr"> 122 </span>  ]
 <span id="L123" class="LineNr"> 123 </span>]
 <span id="L124" class="LineNr"> 124 </span>
 <span id="L125" class="LineNr"> 125 </span><span class="muRecipe">after</span> <span class="Constant"><a href='004-programming-environment.mu.html#L61'>&lt;global-keypress&gt;</a></span> [
 <span id="L126" class="LineNr"> 126 </span>  <span class="Comment"># F4? load all code and run all sandboxes.</span>
 <span id="L127" class="LineNr"> 127 </span>  <span class="Delimiter">{</span>
-<span id="L128" class="LineNr"> 128 </span>    do-run?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65532/F4</span>
-<span id="L129" class="LineNr"> 129 </span>    <span class="muControl">break-unless</span> do-run?
-<span id="L130" class="LineNr"> 130 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L208'>update-status</a> <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[running...       ]</span>, <span class="Constant">245/grey</span>
-<span id="L131" class="LineNr"> 131 </span>    error?:bool <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L143'>run-sandboxes</a> env, <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>
-<span id="L132" class="LineNr"> 132 </span>    <span class="Comment"># F4 might update warnings and results on both sides</span>
-<span id="L133" class="LineNr"> 133 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
-<span id="L134" class="LineNr"> 134 </span>    <span class="Delimiter">{</span>
-<span id="L135" class="LineNr"> 135 </span>      <span class="muControl">break-if</span> error?
-<span id="L136" class="LineNr"> 136 </span>      <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L208'>update-status</a> <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[                 ]</span>, <span class="Constant">245/grey</span>
-<span id="L137" class="LineNr"> 137 </span>    <span class="Delimiter">}</span>
-<span id="L138" class="LineNr"> 138 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L511'>update-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, recipes, current-sandbox, sandbox-in-focus?, env
-<span id="L139" class="LineNr"> 139 </span>    <span class="muControl">loop</span> <span class="Constant">+next-event</span>
+<span id="L128" class="LineNr"> 128 </span>  <span class="Conceal">¦</span> do-run?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65532/F4</span>
+<span id="L129" class="LineNr"> 129 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> do-run?
+<span id="L130" class="LineNr"> 130 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L208'>update-status</a> <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[running...       ]</span>, <span class="Constant">245/grey</span>
+<span id="L131" class="LineNr"> 131 </span>  <span class="Conceal">¦</span> error?:bool <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L143'>run-sandboxes</a> env, <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>
+<span id="L132" class="LineNr"> 132 </span>  <span class="Conceal">¦</span> <span class="Comment"># F4 might update warnings and results on both sides</span>
+<span id="L133" class="LineNr"> 133 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
+<span id="L134" class="LineNr"> 134 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L135" class="LineNr"> 135 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> error?
+<span id="L136" class="LineNr"> 136 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L208'>update-status</a> <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[                 ]</span>, <span class="Constant">245/grey</span>
+<span id="L137" class="LineNr"> 137 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L138" class="LineNr"> 138 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L511'>update-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, recipes, current-sandbox, sandbox-in-focus?, env
+<span id="L139" class="LineNr"> 139 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-event</span>
 <span id="L140" class="LineNr"> 140 </span>  <span class="Delimiter">}</span>
 <span id="L141" class="LineNr"> 141 </span>]
 <span id="L142" class="LineNr"> 142 </span>
@@ -210,24 +211,24 @@ if ('onhashchange' in window) {
 <span id="L149" class="LineNr"> 149 </span><span class="Constant">  <a href='005-sandbox.mu.html#L149'>&lt;run-sandboxes-begin&gt;</a></span>
 <span id="L150" class="LineNr"> 150 </span>  current-sandbox:&amp;:editor <span class="Special">&lt;-</span> get *env, <span class="Constant">current-sandbox:offset</span>
 <span id="L151" class="LineNr"> 151 </span>  <span class="Delimiter">{</span>
-<span id="L152" class="LineNr"> 152 </span>    sandbox-contents:text <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L609'>editor-contents</a> current-sandbox
-<span id="L153" class="LineNr"> 153 </span>    <span class="muControl">break-unless</span> sandbox-contents
-<span id="L154" class="LineNr"> 154 </span>    <span class="Comment"># if contents exist, first save them</span>
-<span id="L155" class="LineNr"> 155 </span>    <span class="Comment"># run them and turn them into a new sandbox</span>
-<span id="L156" class="LineNr"> 156 </span>    new-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> new <span class="Constant">sandbox:type</span>
-<span id="L157" class="LineNr"> 157 </span>    *new-sandbox <span class="Special">&lt;-</span> put *new-sandbox, <span class="Constant">data:offset</span>, sandbox-contents
-<span id="L158" class="LineNr"> 158 </span>    <span class="Comment"># push to head of sandbox list</span>
-<span id="L159" class="LineNr"> 159 </span>    dest:&amp;:sandbox <span class="Special">&lt;-</span> get *env, <span class="Constant">sandbox:offset</span>
-<span id="L160" class="LineNr"> 160 </span>    *new-sandbox <span class="Special">&lt;-</span> put *new-sandbox, <span class="Constant">next-sandbox:offset</span>, dest
-<span id="L161" class="LineNr"> 161 </span>    *env <span class="Special">&lt;-</span> put *env, <span class="Constant">sandbox:offset</span>, new-sandbox
-<span id="L162" class="LineNr"> 162 </span>    <span class="Comment"># update sandbox count</span>
-<span id="L163" class="LineNr"> 163 </span>    sandbox-count:num <span class="Special">&lt;-</span> get *env, <span class="Constant">number-of-sandboxes:offset</span>
-<span id="L164" class="LineNr"> 164 </span>    sandbox-count <span class="Special">&lt;-</span> add sandbox-count,<span class="Constant"> 1</span>
-<span id="L165" class="LineNr"> 165 </span>    *env <span class="Special">&lt;-</span> put *env, <span class="Constant">number-of-sandboxes:offset</span>, sandbox-count
-<span id="L166" class="LineNr"> 166 </span>    <span class="Comment"># clear sandbox editor</span>
-<span id="L167" class="LineNr"> 167 </span>    init:&amp;:duplex-list:char <span class="Special">&lt;-</span> push <span class="Constant">167/§</span>, <span class="Constant">0/tail</span>
-<span id="L168" class="LineNr"> 168 </span>    *current-sandbox <span class="Special">&lt;-</span> put *current-sandbox, <span class="Constant">data:offset</span>, init
-<span id="L169" class="LineNr"> 169 </span>    *current-sandbox <span class="Special">&lt;-</span> put *current-sandbox, <span class="Constant">top-of-screen:offset</span>, init
+<span id="L152" class="LineNr"> 152 </span>  <span class="Conceal">¦</span> sandbox-contents:text <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L609'>editor-contents</a> current-sandbox
+<span id="L153" class="LineNr"> 153 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> sandbox-contents
+<span id="L154" class="LineNr"> 154 </span>  <span class="Conceal">¦</span> <span class="Comment"># if contents exist, first save them</span>
+<span id="L155" class="LineNr"> 155 </span>  <span class="Conceal">¦</span> <span class="Comment"># run them and turn them into a new sandbox</span>
+<span id="L156" class="LineNr"> 156 </span>  <span class="Conceal">¦</span> new-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> new <span class="Constant">sandbox:type</span>
+<span id="L157" class="LineNr"> 157 </span>  <span class="Conceal">¦</span> *new-sandbox <span class="Special">&lt;-</span> put *new-sandbox, <span class="Constant">data:offset</span>, sandbox-contents
+<span id="L158" class="LineNr"> 158 </span>  <span class="Conceal">¦</span> <span class="Comment"># push to head of sandbox list</span>
+<span id="L159" class="LineNr"> 159 </span>  <span class="Conceal">¦</span> dest:&amp;:sandbox <span class="Special">&lt;-</span> get *env, <span class="Constant">sandbox:offset</span>
+<span id="L160" class="LineNr"> 160 </span>  <span class="Conceal">¦</span> *new-sandbox <span class="Special">&lt;-</span> put *new-sandbox, <span class="Constant">next-sandbox:offset</span>, dest
+<span id="L161" class="LineNr"> 161 </span>  <span class="Conceal">¦</span> *env <span class="Special">&lt;-</span> put *env, <span class="Constant">sandbox:offset</span>, new-sandbox
+<span id="L162" class="LineNr"> 162 </span>  <span class="Conceal">¦</span> <span class="Comment"># update sandbox count</span>
+<span id="L163" class="LineNr"> 163 </span>  <span class="Conceal">¦</span> sandbox-count:num <span class="Special">&lt;-</span> get *env, <span class="Constant">number-of-sandboxes:offset</span>
+<span id="L164" class="LineNr"> 164 </span>  <span class="Conceal">¦</span> sandbox-count <span class="Special">&lt;-</span> add sandbox-count,<span class="Constant"> 1</span>
+<span id="L165" class="LineNr"> 165 </span>  <span class="Conceal">¦</span> *env <span class="Special">&lt;-</span> put *env, <span class="Constant">number-of-sandboxes:offset</span>, sandbox-count
+<span id="L166" class="LineNr"> 166 </span>  <span class="Conceal">¦</span> <span class="Comment"># clear sandbox editor</span>
+<span id="L167" class="LineNr"> 167 </span>  <span class="Conceal">¦</span> init:&amp;:duplex-list:char <span class="Special">&lt;-</span> push <span class="Constant">167/§</span>, <span class="Constant">0/tail</span>
+<span id="L168" class="LineNr"> 168 </span>  <span class="Conceal">¦</span> *current-sandbox <span class="Special">&lt;-</span> put *current-sandbox, <span class="Constant">data:offset</span>, init
+<span id="L169" class="LineNr"> 169 </span>  <span class="Conceal">¦</span> *current-sandbox <span class="Special">&lt;-</span> put *current-sandbox, <span class="Constant">top-of-screen:offset</span>, init
 <span id="L170" class="LineNr"> 170 </span>  <span class="Delimiter">}</span>
 <span id="L171" class="LineNr"> 171 </span>  <span class="Comment"># save all sandboxes before running, just in case we die when running</span>
 <span id="L172" class="LineNr"> 172 </span>  <a href='005-sandbox.mu.html#L215'>save-sandboxes</a> env, <a href='../088file.mu.html#L11'>resources</a>
@@ -235,11 +236,11 @@ if ('onhashchange' in window) {
 <span id="L174" class="LineNr"> 174 </span>  curr:&amp;:sandbox <span class="Special">&lt;-</span> get *env, <span class="Constant">sandbox:offset</span>
 <span id="L175" class="LineNr"> 175 </span>  idx:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
 <span id="L176" class="LineNr"> 176 </span>  <span class="Delimiter">{</span>
-<span id="L177" class="LineNr"> 177 </span>    <span class="muControl">break-unless</span> curr
-<span id="L178" class="LineNr"> 178 </span>    curr <span class="Special">&lt;-</span> update-sandbox curr, env, idx
-<span id="L179" class="LineNr"> 179 </span>    curr <span class="Special">&lt;-</span> get *curr, <span class="Constant">next-sandbox:offset</span>
-<span id="L180" class="LineNr"> 180 </span>    idx <span class="Special">&lt;-</span> add idx,<span class="Constant"> 1</span>
-<span id="L181" class="LineNr"> 181 </span>    <span class="muControl">loop</span>
+<span id="L177" class="LineNr"> 177 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> curr
+<span id="L178" class="LineNr"> 178 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> update-sandbox curr, env, idx
+<span id="L179" class="LineNr"> 179 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> get *curr, <span class="Constant">next-sandbox:offset</span>
+<span id="L180" class="LineNr"> 180 </span>  <span class="Conceal">¦</span> idx <span class="Special">&lt;-</span> add idx,<span class="Constant"> 1</span>
+<span id="L181" class="LineNr"> 181 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L182" class="LineNr"> 182 </span>  <span class="Delimiter">}</span>
 <span id="L183" class="LineNr"> 183 </span><span class="Constant">  <a href='005-sandbox.mu.html#L183'>&lt;run-sandboxes-end&gt;</a></span>
 <span id="L184" class="LineNr"> 184 </span>]
@@ -282,14 +283,14 @@ if ('onhashchange' in window) {
 <span id="L221" class="LineNr"> 221 </span>  curr:&amp;:sandbox <span class="Special">&lt;-</span> get *env, <span class="Constant">sandbox:offset</span>
 <span id="L222" class="LineNr"> 222 </span>  idx:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
 <span id="L223" class="LineNr"> 223 </span>  <span class="Delimiter">{</span>
-<span id="L224" class="LineNr"> 224 </span>    <span class="muControl">break-unless</span> curr
-<span id="L225" class="LineNr"> 225 </span>    data:text <span class="Special">&lt;-</span> get *curr, <span class="Constant">data:offset</span>
-<span id="L226" class="LineNr"> 226 </span>    filename:text <span class="Special">&lt;-</span> append <span class="Constant">[lesson/]</span>, idx
-<span id="L227" class="LineNr"> 227 </span>    <a href='../088file.mu.html#L11'>resources</a> <span class="Special">&lt;-</span> <a href='../088file.mu.html#L127'>dump</a> <a href='../088file.mu.html#L11'>resources</a>, filename, data
-<span id="L228" class="LineNr"> 228 </span><span class="Constant">    <a href='005-sandbox.mu.html#L228'>&lt;end-save-sandbox&gt;</a></span>
-<span id="L229" class="LineNr"> 229 </span>    idx <span class="Special">&lt;-</span> add idx,<span class="Constant"> 1</span>
-<span id="L230" class="LineNr"> 230 </span>    curr <span class="Special">&lt;-</span> get *curr, <span class="Constant">next-sandbox:offset</span>
-<span id="L231" class="LineNr"> 231 </span>    <span class="muControl">loop</span>
+<span id="L224" class="LineNr"> 224 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> curr
+<span id="L225" class="LineNr"> 225 </span>  <span class="Conceal">¦</span> data:text <span class="Special">&lt;-</span> get *curr, <span class="Constant">data:offset</span>
+<span id="L226" class="LineNr"> 226 </span>  <span class="Conceal">¦</span> filename:text <span class="Special">&lt;-</span> append <span class="Constant">[lesson/]</span>, idx
+<span id="L227" class="LineNr"> 227 </span>  <span class="Conceal">¦</span> <a href='../088file.mu.html#L11'>resources</a> <span class="Special">&lt;-</span> <a href='../088file.mu.html#L127'>dump</a> <a href='../088file.mu.html#L11'>resources</a>, filename, data
+<span id="L228" class="LineNr"> 228 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> <a href='005-sandbox.mu.html#L228'>&lt;end-save-sandbox&gt;</a></span>
+<span id="L229" class="LineNr"> 229 </span>  <span class="Conceal">¦</span> idx <span class="Special">&lt;-</span> add idx,<span class="Constant"> 1</span>
+<span id="L230" class="LineNr"> 230 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> get *curr, <span class="Constant">next-sandbox:offset</span>
+<span id="L231" class="LineNr"> 231 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L232" class="LineNr"> 232 </span>  <span class="Delimiter">}</span>
 <span id="L233" class="LineNr"> 233 </span>]
 <span id="L234" class="LineNr"> 234 </span>
@@ -304,11 +305,11 @@ if ('onhashchange' in window) {
 <span id="L243" class="LineNr"> 243 </span>  <span class="Comment"># render sandbox editor</span>
 <span id="L244" class="LineNr"> 244 </span>  render-from:num <span class="Special">&lt;-</span> get *env, <span class="Constant">render-from:offset</span>
 <span id="L245" class="LineNr"> 245 </span>  <span class="Delimiter">{</span>
-<span id="L246" class="LineNr"> 246 </span>    render-current-sandbox?:bool <span class="Special">&lt;-</span> equal render-from,<span class="Constant"> -1</span>
-<span id="L247" class="LineNr"> 247 </span>    <span class="muControl">break-unless</span> render-current-sandbox?
-<span id="L248" class="LineNr"> 248 </span>    row, column, <a href='../081print.mu.html#L4'>screen</a>, current-sandbox <span class="Special">&lt;-</span> call render-editor, <a href='../081print.mu.html#L4'>screen</a>, current-sandbox
-<span id="L249" class="LineNr"> 249 </span>    <a href='001-editor.mu.html#L224'>clear-screen-from</a> <a href='../081print.mu.html#L4'>screen</a>, row, column, left, right
-<span id="L250" class="LineNr"> 250 </span>    row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
+<span id="L246" class="LineNr"> 246 </span>  <span class="Conceal">¦</span> render-current-sandbox?:bool <span class="Special">&lt;-</span> equal render-from,<span class="Constant"> -1</span>
+<span id="L247" class="LineNr"> 247 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> render-current-sandbox?
+<span id="L248" class="LineNr"> 248 </span>  <span class="Conceal">¦</span> row, column, <a href='../081print.mu.html#L4'>screen</a>, current-sandbox <span class="Special">&lt;-</span> call render-editor, <a href='../081print.mu.html#L4'>screen</a>, current-sandbox
+<span id="L249" class="LineNr"> 249 </span>  <span class="Conceal">¦</span> <a href='001-editor.mu.html#L224'>clear-screen-from</a> <a href='../081print.mu.html#L4'>screen</a>, row, column, left, right
+<span id="L250" class="LineNr"> 250 </span>  <span class="Conceal">¦</span> row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
 <span id="L251" class="LineNr"> 251 </span>  <span class="Delimiter">}</span>
 <span id="L252" class="LineNr"> 252 </span>  <span class="Comment"># render sandboxes</span>
 <span id="L253" class="LineNr"> 253 </span>  <a href='002-typing.mu.html#L1056'>draw-horizontal</a> <a href='../081print.mu.html#L4'>screen</a>, row, left, right
@@ -326,45 +327,45 @@ if ('onhashchange' in window) {
 <span id="L265" class="LineNr"> 265 </span>  <span class="muControl">return-if</span> at-bottom?:bool
 <span id="L266" class="LineNr"> 266 </span>  hidden?:bool <span class="Special">&lt;-</span> lesser-than idx, render-from
 <span id="L267" class="LineNr"> 267 </span>  <span class="Delimiter">{</span>
-<span id="L268" class="LineNr"> 268 </span>    <span class="muControl">break-if</span> hidden?
-<span id="L269" class="LineNr"> 269 </span>    <span class="Comment"># render sandbox menu</span>
-<span id="L270" class="LineNr"> 270 </span>    row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
-<span id="L271" class="LineNr"> 271 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, left
-<span id="L272" class="LineNr"> 272 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L314'>render-sandbox-menu</a> <a href='../081print.mu.html#L4'>screen</a>, idx, left, right
-<span id="L273" class="LineNr"> 273 </span>    <span class="Comment"># save menu row so we can detect clicks to it later</span>
-<span id="L274" class="LineNr"> 274 </span>    *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">starting-row-on-screen:offset</span>, row
-<span id="L275" class="LineNr"> 275 </span>    <span class="Comment"># render sandbox contents</span>
-<span id="L276" class="LineNr"> 276 </span>    row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
-<span id="L277" class="LineNr"> 277 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, left
-<span id="L278" class="LineNr"> 278 </span>    sandbox-data:text <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">data:offset</span>
-<span id="L279" class="LineNr"> 279 </span>    row, <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L529'>render-code</a> <a href='../081print.mu.html#L4'>screen</a>, sandbox-data, left, right, row
-<span id="L280" class="LineNr"> 280 </span>    *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">code-ending-row-on-screen:offset</span>, row
-<span id="L281" class="LineNr"> 281 </span>    <span class="Comment"># render sandbox warnings, screen or response, in that order</span>
-<span id="L282" class="LineNr"> 282 </span>    sandbox-response:text <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">response:offset</span>
-<span id="L283" class="LineNr"> 283 </span><span class="Constant">    <a href='005-sandbox.mu.html#L283'>&lt;render-sandbox-results&gt;</a></span>
-<span id="L284" class="LineNr"> 284 </span>    <span class="Delimiter">{</span>
-<span id="L285" class="LineNr"> 285 </span>      sandbox-screen:&amp;:<a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> get *sandbox, <span class="Constant"><a href='../081print.mu.html#L4'>screen</a>:offset</span>
-<span id="L286" class="LineNr"> 286 </span>      empty-screen?:bool <span class="Special">&lt;-</span> <a href='../081print.mu.html#L60'>fake-screen-is-empty?</a> sandbox-screen
-<span id="L287" class="LineNr"> 287 </span>      <span class="muControl">break-if</span> empty-screen?
-<span id="L288" class="LineNr"> 288 </span>      row, <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L451'>render-screen</a> <a href='../081print.mu.html#L4'>screen</a>, sandbox-screen, left, right, row
-<span id="L289" class="LineNr"> 289 </span>    <span class="Delimiter">}</span>
-<span id="L290" class="LineNr"> 290 </span>    <span class="Delimiter">{</span>
-<span id="L291" class="LineNr"> 291 </span>      <span class="muControl">break-unless</span> empty-screen?
-<span id="L292" class="LineNr"> 292 </span><span class="Constant">      <a href='005-sandbox.mu.html#L292'>&lt;render-sandbox-response&gt;</a></span>
-<span id="L293" class="LineNr"> 293 </span>      row, <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L356'>render-text</a> <a href='../081print.mu.html#L4'>screen</a>, sandbox-response, left, right, <span class="Constant">245/grey</span>, row
-<span id="L294" class="LineNr"> 294 </span>    <span class="Delimiter">}</span>
-<span id="L295" class="LineNr"> 295 </span><span class="Constant">    +render-sandbox-end</span>
-<span id="L296" class="LineNr"> 296 </span>    at-bottom?:bool <span class="Special">&lt;-</span> greater-or-equal row, <a href='../081print.mu.html#L594'>screen-height</a>
-<span id="L297" class="LineNr"> 297 </span>    <span class="muControl">return-if</span> at-bottom?
-<span id="L298" class="LineNr"> 298 </span>    <span class="Comment"># draw solid line after sandbox</span>
-<span id="L299" class="LineNr"> 299 </span>    <a href='002-typing.mu.html#L1056'>draw-horizontal</a> <a href='../081print.mu.html#L4'>screen</a>, row, left, right
+<span id="L268" class="LineNr"> 268 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> hidden?
+<span id="L269" class="LineNr"> 269 </span>  <span class="Conceal">¦</span> <span class="Comment"># render sandbox menu</span>
+<span id="L270" class="LineNr"> 270 </span>  <span class="Conceal">¦</span> row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
+<span id="L271" class="LineNr"> 271 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, left
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+<span id="L273" class="LineNr"> 273 </span>  <span class="Conceal">¦</span> <span class="Comment"># save menu row so we can detect clicks to it later</span>
+<span id="L274" class="LineNr"> 274 </span>  <span class="Conceal">¦</span> *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">starting-row-on-screen:offset</span>, row
+<span id="L275" class="LineNr"> 275 </span>  <span class="Conceal">¦</span> <span class="Comment"># render sandbox contents</span>
+<span id="L276" class="LineNr"> 276 </span>  <span class="Conceal">¦</span> row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
+<span id="L277" class="LineNr"> 277 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, left
+<span id="L278" class="LineNr"> 278 </span>  <span class="Conceal">¦</span> sandbox-data:text <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">data:offset</span>
+<span id="L279" class="LineNr"> 279 </span>  <span class="Conceal">¦</span> row, <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L529'>render-code</a> <a href='../081print.mu.html#L4'>screen</a>, sandbox-data, left, right, row
+<span id="L280" class="LineNr"> 280 </span>  <span class="Conceal">¦</span> *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">code-ending-row-on-screen:offset</span>, row
+<span id="L281" class="LineNr"> 281 </span>  <span class="Conceal">¦</span> <span class="Comment"># render sandbox warnings, screen or response, in that order</span>
+<span id="L282" class="LineNr"> 282 </span>  <span class="Conceal">¦</span> sandbox-response:text <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">response:offset</span>
+<span id="L283" class="LineNr"> 283 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> <a href='005-sandbox.mu.html#L283'>&lt;render-sandbox-results&gt;</a></span>
+<span id="L284" class="LineNr"> 284 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L285" class="LineNr"> 285 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> sandbox-screen:&amp;:<a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> get *sandbox, <span class="Constant"><a href='../081print.mu.html#L4'>screen</a>:offset</span>
+<span id="L286" class="LineNr"> 286 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> empty-screen?:bool <span class="Special">&lt;-</span> <a href='../081print.mu.html#L60'>fake-screen-is-empty?</a> sandbox-screen
+<span id="L287" class="LineNr"> 287 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> empty-screen?
+<span id="L288" class="LineNr"> 288 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> row, <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L451'>render-screen</a> <a href='../081print.mu.html#L4'>screen</a>, sandbox-screen, left, right, row
+<span id="L289" class="LineNr"> 289 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L290" class="LineNr"> 290 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L291" class="LineNr"> 291 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> empty-screen?
+<span id="L292" class="LineNr"> 292 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> <a href='005-sandbox.mu.html#L292'>&lt;render-sandbox-response&gt;</a></span>
+<span id="L293" class="LineNr"> 293 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> row, <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L356'>render-text</a> <a href='../081print.mu.html#L4'>screen</a>, sandbox-response, left, right, <span class="Constant">245/grey</span>, row
+<span id="L294" class="LineNr"> 294 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L295" class="LineNr"> 295 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> +render-sandbox-end</span>
+<span id="L296" class="LineNr"> 296 </span>  <span class="Conceal">¦</span> at-bottom?:bool <span class="Special">&lt;-</span> greater-or-equal row, <a href='../081print.mu.html#L594'>screen-height</a>
+<span id="L297" class="LineNr"> 297 </span>  <span class="Conceal">¦</span> <span class="muControl">return-if</span> at-bottom?
+<span id="L298" class="LineNr"> 298 </span>  <span class="Conceal">¦</span> <span class="Comment"># draw solid line after sandbox</span>
+<span id="L299" class="LineNr"> 299 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L1056'>draw-horizontal</a> <a href='../081print.mu.html#L4'>screen</a>, row, left, right
 <span id="L300" class="LineNr"> 300 </span>  <span class="Delimiter">}</span>
 <span id="L301" class="LineNr"> 301 </span>  <span class="Comment"># if hidden, reset row attributes</span>
 <span id="L302" class="LineNr"> 302 </span>  <span class="Delimiter">{</span>
-<span id="L303" class="LineNr"> 303 </span>    <span class="muControl">break-unless</span> hidden?
-<span id="L304" class="LineNr"> 304 </span>    *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">starting-row-on-screen:offset</span>,<span class="Constant"> 0</span>
-<span id="L305" class="LineNr"> 305 </span>    *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">code-ending-row-on-screen:offset</span>,<span class="Constant"> 0</span>
-<span id="L306" class="LineNr"> 306 </span><span class="Constant">    <a href='005-sandbox.mu.html#L306'>&lt;end-render-sandbox-reset-hidden&gt;</a></span>
+<span id="L303" class="LineNr"> 303 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> hidden?
+<span id="L304" class="LineNr"> 304 </span>  <span class="Conceal">¦</span> *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">starting-row-on-screen:offset</span>,<span class="Constant"> 0</span>
+<span id="L305" class="LineNr"> 305 </span>  <span class="Conceal">¦</span> *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">code-ending-row-on-screen:offset</span>,<span class="Constant"> 0</span>
+<span id="L306" class="LineNr"> 306 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> <a href='005-sandbox.mu.html#L306'>&lt;end-render-sandbox-reset-hidden&gt;</a></span>
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 <span id="L309" class="LineNr"> 309 </span>  next-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">next-sandbox:offset</span>
@@ -424,52 +425,52 @@ if ('onhashchange' in window) {
 <span id="L363" class="LineNr"> 363 </span>  i:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
 <span id="L364" class="LineNr"> 364 </span>  len:num <span class="Special">&lt;-</span> length *s
 <span id="L365" class="LineNr"> 365 </span>  <span class="Delimiter">{</span>
-<span id="L366" class="LineNr"> 366 </span><span class="Constant">    +next-character</span>
-<span id="L367" class="LineNr"> 367 </span>    done?:bool <span class="Special">&lt;-</span> greater-or-equal i, len
-<span id="L368" class="LineNr"> 368 </span>    <span class="muControl">break-if</span> done?
-<span id="L369" class="LineNr"> 369 </span>    done? <span class="Special">&lt;-</span> greater-or-equal row, <a href='../081print.mu.html#L594'>screen-height</a>
-<span id="L370" class="LineNr"> 370 </span>    <span class="muControl">break-if</span> done?
-<span id="L371" class="LineNr"> 371 </span>    c:char <span class="Special">&lt;-</span> index *s, i
-<span id="L372" class="LineNr"> 372 </span>    <span class="Delimiter">{</span>
-<span id="L373" class="LineNr"> 373 </span>      <span class="Comment"># at right? wrap.</span>
-<span id="L374" class="LineNr"> 374 </span>      at-right?:bool <span class="Special">&lt;-</span> equal column, right
-<span id="L375" class="LineNr"> 375 </span>      <span class="muControl">break-unless</span> at-right?
-<span id="L376" class="LineNr"> 376 </span>      <span class="Comment"># print wrap icon</span>
-<span id="L377" class="LineNr"> 377 </span>      wrap-icon:char <span class="Special">&lt;-</span> copy <span class="Constant">8617/loop-back-to-left</span>
-<span id="L378" class="LineNr"> 378 </span>      print <a href='../081print.mu.html#L4'>screen</a>, wrap-icon, <span class="Constant">245/grey</span>
-<span id="L379" class="LineNr"> 379 </span>      column <span class="Special">&lt;-</span> copy left
-<span id="L380" class="LineNr"> 380 </span>      row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
-<span id="L381" class="LineNr"> 381 </span>      <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, column
-<span id="L382" class="LineNr"> 382 </span>      <span class="muControl">loop</span> <span class="Constant">+next-character</span>  <span class="Comment"># retry i</span>
-<span id="L383" class="LineNr"> 383 </span>    <span class="Delimiter">}</span>
-<span id="L384" class="LineNr"> 384 </span>    i <span class="Special">&lt;-</span> add i,<span class="Constant"> 1</span>
-<span id="L385" class="LineNr"> 385 </span>    <span class="Delimiter">{</span>
-<span id="L386" class="LineNr"> 386 </span>      <span class="Comment"># newline? move to left rather than 0</span>
-<span id="L387" class="LineNr"> 387 </span>      newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
-<span id="L388" class="LineNr"> 388 </span>      <span class="muControl">break-unless</span> newline?
-<span id="L389" class="LineNr"> 389 </span>      <span class="Comment"># clear rest of line in this window</span>
-<span id="L390" class="LineNr"> 390 </span>      <span class="Delimiter">{</span>
-<span id="L391" class="LineNr"> 391 </span>        done?:bool <span class="Special">&lt;-</span> greater-than column, right
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-<span id="L393" class="LineNr"> 393 </span>        space:char <span class="Special">&lt;-</span> copy <span class="Constant">32/space</span>
-<span id="L394" class="LineNr"> 394 </span>        print <a href='../081print.mu.html#L4'>screen</a>, space
-<span id="L395" class="LineNr"> 395 </span>        column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
-<span id="L396" class="LineNr"> 396 </span>        <span class="muControl">loop</span>
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-<span id="L398" class="LineNr"> 398 </span>      row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
-<span id="L399" class="LineNr"> 399 </span>      column <span class="Special">&lt;-</span> copy left
-<span id="L400" class="LineNr"> 400 </span>      <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, column
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-<span id="L403" class="LineNr"> 403 </span>    print <a href='../081print.mu.html#L4'>screen</a>, c, color
-<span id="L404" class="LineNr"> 404 </span>    column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
-<span id="L405" class="LineNr"> 405 </span>    <span class="muControl">loop</span>
+<span id="L366" class="LineNr"> 366 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> +next-character</span>
+<span id="L367" class="LineNr"> 367 </span>  <span class="Conceal">¦</span> done?:bool <span class="Special">&lt;-</span> greater-or-equal i, len
+<span id="L368" class="LineNr"> 368 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
+<span id="L369" class="LineNr"> 369 </span>  <span class="Conceal">¦</span> done? <span class="Special">&lt;-</span> greater-or-equal row, <a href='../081print.mu.html#L594'>screen-height</a>
+<span id="L370" class="LineNr"> 370 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
+<span id="L371" class="LineNr"> 371 </span>  <span class="Conceal">¦</span> c:char <span class="Special">&lt;-</span> index *s, i
+<span id="L372" class="LineNr"> 372 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L373" class="LineNr"> 373 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># at right? wrap.</span>
+<span id="L374" class="LineNr"> 374 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-right?:bool <span class="Special">&lt;-</span> equal column, right
+<span id="L375" class="LineNr"> 375 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-right?
+<span id="L376" class="LineNr"> 376 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># print wrap icon</span>
+<span id="L377" class="LineNr"> 377 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> wrap-icon:char <span class="Special">&lt;-</span> copy <span class="Constant">8617/loop-back-to-left</span>
+<span id="L378" class="LineNr"> 378 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, wrap-icon, <span class="Constant">245/grey</span>
+<span id="L379" class="LineNr"> 379 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> copy left
+<span id="L380" class="LineNr"> 380 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
+<span id="L381" class="LineNr"> 381 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, column
+<span id="L382" class="LineNr"> 382 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-character</span>  <span class="Comment"># retry i</span>
+<span id="L383" class="LineNr"> 383 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L384" class="LineNr"> 384 </span>  <span class="Conceal">¦</span> i <span class="Special">&lt;-</span> add i,<span class="Constant"> 1</span>
+<span id="L385" class="LineNr"> 385 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L386" class="LineNr"> 386 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># newline? move to left rather than 0</span>
+<span id="L387" class="LineNr"> 387 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
+<span id="L388" class="LineNr"> 388 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> newline?
+<span id="L389" class="LineNr"> 389 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># clear rest of line in this window</span>
+<span id="L390" class="LineNr"> 390 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L391" class="LineNr"> 391 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> done?:bool <span class="Special">&lt;-</span> greater-than column, right
+<span id="L392" class="LineNr"> 392 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
+<span id="L393" class="LineNr"> 393 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> space:char <span class="Special">&lt;-</span> copy <span class="Constant">32/space</span>
+<span id="L394" class="LineNr"> 394 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, space
+<span id="L395" class="LineNr"> 395 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
+<span id="L396" class="LineNr"> 396 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span>
+<span id="L397" class="LineNr"> 397 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L398" class="LineNr"> 398 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
+<span id="L399" class="LineNr"> 399 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> copy left
+<span id="L400" class="LineNr"> 400 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, column
+<span id="L401" class="LineNr"> 401 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-character</span>
+<span id="L402" class="LineNr"> 402 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L403" class="LineNr"> 403 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, c, color
+<span id="L404" class="LineNr"> 404 </span>  <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
+<span id="L405" class="LineNr"> 405 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L406" class="LineNr"> 406 </span>  <span class="Delimiter">}</span>
 <span id="L407" class="LineNr"> 407 </span>  was-at-left?:bool <span class="Special">&lt;-</span> equal column, left
 <span id="L408" class="LineNr"> 408 </span>  <a href='../081print.mu.html#L408'>clear-line-until</a> <a href='../081print.mu.html#L4'>screen</a>, right
 <span id="L409" class="LineNr"> 409 </span>  <span class="Delimiter">{</span>
-<span id="L410" class="LineNr"> 410 </span>    <span class="muControl">break-if</span> was-at-left?
-<span id="L411" class="LineNr"> 411 </span>    row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
+<span id="L410" class="LineNr"> 410 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> was-at-left?
+<span id="L411" class="LineNr"> 411 </span>  <span class="Conceal">¦</span> row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
 <span id="L412" class="LineNr"> 412 </span>  <span class="Delimiter">}</span>
 <span id="L413" class="LineNr"> 413 </span>  <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, left
 <span id="L414" class="LineNr"> 414 </span>]
@@ -483,25 +484,25 @@ if ('onhashchange' in window) {
 <span id="L422" class="LineNr"> 422 </span>  curr:&amp;:sandbox <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
 <span id="L423" class="LineNr"> 423 </span>  <a href='../065duplex_list.mu.html#L36'>prev</a>:&amp;:sandbox <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
 <span id="L424" class="LineNr"> 424 </span>  <span class="Delimiter">{</span>
-<span id="L425" class="LineNr"> 425 </span>    filename:text <span class="Special">&lt;-</span> append <span class="Constant">[lesson/]</span>, idx
-<span id="L426" class="LineNr"> 426 </span>    contents:text <span class="Special">&lt;-</span> <a href='../088file.mu.html#L38'>slurp</a> <a href='../088file.mu.html#L11'>resources</a>, filename
-<span id="L427" class="LineNr"> 427 </span>    <span class="muControl">break-unless</span> contents  <span class="Comment"># stop at first error; assuming file didn't exist</span>
-<span id="L428" class="LineNr"> 428 </span>                           <span class="Comment"># todo: handle empty sandbox</span>
-<span id="L429" class="LineNr"> 429 </span>    <span class="Comment"># create new sandbox for file</span>
-<span id="L430" class="LineNr"> 430 </span>    curr <span class="Special">&lt;-</span> new <span class="Constant">sandbox:type</span>
-<span id="L431" class="LineNr"> 431 </span>    *curr <span class="Special">&lt;-</span> put *curr, <span class="Constant">data:offset</span>, contents
-<span id="L432" class="LineNr"> 432 </span><span class="Constant">    <a href='005-sandbox.mu.html#L432'>&lt;end-restore-sandbox&gt;</a></span>
-<span id="L433" class="LineNr"> 433 </span>    <span class="Delimiter">{</span>
-<span id="L434" class="LineNr"> 434 </span>      <span class="muControl">break-if</span> idx
-<span id="L435" class="LineNr"> 435 </span>      *env <span class="Special">&lt;-</span> put *env, <span class="Constant">sandbox:offset</span>, curr
-<span id="L436" class="LineNr"> 436 </span>    <span class="Delimiter">}</span>
-<span id="L437" class="LineNr"> 437 </span>    <span class="Delimiter">{</span>
-<span id="L438" class="LineNr"> 438 </span>      <span class="muControl">break-unless</span> idx
-<span id="L439" class="LineNr"> 439 </span>      *prev <span class="Special">&lt;-</span> put *prev, <span class="Constant">next-sandbox:offset</span>, curr
-<span id="L440" class="LineNr"> 440 </span>    <span class="Delimiter">}</span>
-<span id="L441" class="LineNr"> 441 </span>    idx <span class="Special">&lt;-</span> add idx,<span class="Constant"> 1</span>
-<span id="L442" class="LineNr"> 442 </span>    <a href='../065duplex_list.mu.html#L36'>prev</a> <span class="Special">&lt;-</span> copy curr
-<span id="L443" class="LineNr"> 443 </span>    <span class="muControl">loop</span>
+<span id="L425" class="LineNr"> 425 </span>  <span class="Conceal">¦</span> filename:text <span class="Special">&lt;-</span> append <span class="Constant">[lesson/]</span>, idx
+<span id="L426" class="LineNr"> 426 </span>  <span class="Conceal">¦</span> contents:text <span class="Special">&lt;-</span> <a href='../088file.mu.html#L38'>slurp</a> <a href='../088file.mu.html#L11'>resources</a>, filename
+<span id="L427" class="LineNr"> 427 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> contents  <span class="Comment"># stop at first error; assuming file didn't exist</span>
+<span id="L428" class="LineNr"> 428 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span>      <span class="Comment"># todo: handle empty sandbox</span>
+<span id="L429" class="LineNr"> 429 </span>  <span class="Conceal">¦</span> <span class="Comment"># create new sandbox for file</span>
+<span id="L430" class="LineNr"> 430 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> new <span class="Constant">sandbox:type</span>
+<span id="L431" class="LineNr"> 431 </span>  <span class="Conceal">¦</span> *curr <span class="Special">&lt;-</span> put *curr, <span class="Constant">data:offset</span>, contents
+<span id="L432" class="LineNr"> 432 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> <a href='005-sandbox.mu.html#L432'>&lt;end-restore-sandbox&gt;</a></span>
+<span id="L433" class="LineNr"> 433 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L434" class="LineNr"> 434 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> idx
+<span id="L435" class="LineNr"> 435 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> *env <span class="Special">&lt;-</span> put *env, <span class="Constant">sandbox:offset</span>, curr
+<span id="L436" class="LineNr"> 436 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L437" class="LineNr"> 437 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L438" class="LineNr"> 438 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> idx
+<span id="L439" class="LineNr"> 439 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> *prev <span class="Special">&lt;-</span> put *prev, <span class="Constant">next-sandbox:offset</span>, curr
+<span id="L440" class="LineNr"> 440 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L441" class="LineNr"> 441 </span>  <span class="Conceal">¦</span> idx <span class="Special">&lt;-</span> add idx,<span class="Constant"> 1</span>
+<span id="L442" class="LineNr"> 442 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a> <span class="Special">&lt;-</span> copy curr
+<span id="L443" class="LineNr"> 443 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L444" class="LineNr"> 444 </span>  <span class="Delimiter">}</span>
 <span id="L445" class="LineNr"> 445 </span>  <span class="Comment"># update sandbox count</span>
 <span id="L446" class="LineNr"> 446 </span>  *env <span class="Special">&lt;-</span> put *env, <span class="Constant">number-of-sandboxes:offset</span>, idx
@@ -527,50 +528,50 @@ if ('onhashchange' in window) {
 <span id="L466" class="LineNr"> 466 </span>  len:num <span class="Special">&lt;-</span> length *buf
 <span id="L467" class="LineNr"> 467 </span>  <a href='../081print.mu.html#L594'>screen-height</a>:num <span class="Special">&lt;-</span> <a href='../081print.mu.html#L594'>screen-height</a> <a href='../081print.mu.html#L4'>screen</a>
 <span id="L468" class="LineNr"> 468 </span>  <span class="Delimiter">{</span>
-<span id="L469" class="LineNr"> 469 </span>    done?:bool <span class="Special">&lt;-</span> greater-or-equal i, len
-<span id="L470" class="LineNr"> 470 </span>    <span class="muControl">break-if</span> done?
-<span id="L471" class="LineNr"> 471 </span>    done? <span class="Special">&lt;-</span> greater-or-equal row, <a href='../081print.mu.html#L594'>screen-height</a>
-<span id="L472" class="LineNr"> 472 </span>    <span class="muControl">break-if</span> done?
-<span id="L473" class="LineNr"> 473 </span>    column <span class="Special">&lt;-</span> copy left
-<span id="L474" class="LineNr"> 474 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, column
-<span id="L475" class="LineNr"> 475 </span>    <span class="Comment"># initial leader for each row: two spaces and a '.'</span>
-<span id="L476" class="LineNr"> 476 </span>    space:char <span class="Special">&lt;-</span> copy <span class="Constant">32/space</span>
-<span id="L477" class="LineNr"> 477 </span>    print <a href='../081print.mu.html#L4'>screen</a>, space, <span class="Constant">245/grey</span>
-<span id="L478" class="LineNr"> 478 </span>    print <a href='../081print.mu.html#L4'>screen</a>, space, <span class="Constant">245/grey</span>
-<span id="L479" class="LineNr"> 479 </span>    full-stop:char <span class="Special">&lt;-</span> copy <span class="Constant">46/period</span>
-<span id="L480" class="LineNr"> 480 </span>    print <a href='../081print.mu.html#L4'>screen</a>, full-stop, <span class="Constant">245/grey</span>
-<span id="L481" class="LineNr"> 481 </span>    column <span class="Special">&lt;-</span> add left,<span class="Constant"> 3</span>
-<span id="L482" class="LineNr"> 482 </span>    <span class="Delimiter">{</span>
-<span id="L483" class="LineNr"> 483 </span>      <span class="Comment"># print row</span>
-<span id="L484" class="LineNr"> 484 </span>      row-done?:bool <span class="Special">&lt;-</span> greater-or-equal column, max-column
-<span id="L485" class="LineNr"> 485 </span>      <span class="muControl">break-if</span> row-done?
-<span id="L486" class="LineNr"> 486 </span>      curr:<a href='../081print.mu.html#L12'>screen-cell</a> <span class="Special">&lt;-</span> index *buf, i
-<span id="L487" class="LineNr"> 487 </span>      c:char <span class="Special">&lt;-</span> get curr, <span class="Constant">contents:offset</span>
-<span id="L488" class="LineNr"> 488 </span>      color:num <span class="Special">&lt;-</span> get curr, <span class="Constant">color:offset</span>
-<span id="L489" class="LineNr"> 489 </span>      <span class="Delimiter">{</span>
-<span id="L490" class="LineNr"> 490 </span>        <span class="Comment"># damp whites down to grey</span>
-<span id="L491" class="LineNr"> 491 </span>        white?:bool <span class="Special">&lt;-</span> equal color, <span class="Constant">7/white</span>
-<span id="L492" class="LineNr"> 492 </span>        <span class="muControl">break-unless</span> white?
-<span id="L493" class="LineNr"> 493 </span>        color <span class="Special">&lt;-</span> copy <span class="Constant">245/grey</span>
-<span id="L494" class="LineNr"> 494 </span>      <span class="Delimiter">}</span>
-<span id="L495" class="LineNr"> 495 </span>      print <a href='../081print.mu.html#L4'>screen</a>, c, color
-<span id="L496" class="LineNr"> 496 </span>      column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
-<span id="L497" class="LineNr"> 497 </span>      i <span class="Special">&lt;-</span> add i,<span class="Constant"> 1</span>
-<span id="L498" class="LineNr"> 498 </span>      <span class="muControl">loop</span>
-<span id="L499" class="LineNr"> 499 </span>    <span class="Delimiter">}</span>
-<span id="L500" class="LineNr"> 500 </span>    <span class="Comment"># print final '.'</span>
-<span id="L501" class="LineNr"> 501 </span>    print <a href='../081print.mu.html#L4'>screen</a>, full-stop, <span class="Constant">245/grey</span>
-<span id="L502" class="LineNr"> 502 </span>    column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
-<span id="L503" class="LineNr"> 503 </span>    <span class="Delimiter">{</span>
-<span id="L504" class="LineNr"> 504 </span>      <span class="Comment"># clear rest of current line</span>
-<span id="L505" class="LineNr"> 505 </span>      line-done?:bool <span class="Special">&lt;-</span> greater-than column, right
-<span id="L506" class="LineNr"> 506 </span>      <span class="muControl">break-if</span> line-done?
-<span id="L507" class="LineNr"> 507 </span>      print <a href='../081print.mu.html#L4'>screen</a>, space
-<span id="L508" class="LineNr"> 508 </span>      column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
-<span id="L509" class="LineNr"> 509 </span>      <span class="muControl">loop</span>
-<span id="L510" class="LineNr"> 510 </span>    <span class="Delimiter">}</span>
-<span id="L511" class="LineNr"> 511 </span>    row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
-<span id="L512" class="LineNr"> 512 </span>    <span class="muControl">loop</span>
+<span id="L469" class="LineNr"> 469 </span>  <span class="Conceal">¦</span> done?:bool <span class="Special">&lt;-</span> greater-or-equal i, len
+<span id="L470" class="LineNr"> 470 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
+<span id="L471" class="LineNr"> 471 </span>  <span class="Conceal">¦</span> done? <span class="Special">&lt;-</span> greater-or-equal row, <a href='../081print.mu.html#L594'>screen-height</a>
+<span id="L472" class="LineNr"> 472 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
+<span id="L473" class="LineNr"> 473 </span>  <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> copy left
+<span id="L474" class="LineNr"> 474 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, row, column
+<span id="L475" class="LineNr"> 475 </span>  <span class="Conceal">¦</span> <span class="Comment"># initial leader for each row: two spaces and a '.'</span>
+<span id="L476" class="LineNr"> 476 </span>  <span class="Conceal">¦</span> space:char <span class="Special">&lt;-</span> copy <span class="Constant">32/space</span>
+<span id="L477" class="LineNr"> 477 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, space, <span class="Constant">245/grey</span>
+<span id="L478" class="LineNr"> 478 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, space, <span class="Constant">245/grey</span>
+<span id="L479" class="LineNr"> 479 </span>  <span class="Conceal">¦</span> full-stop:char <span class="Special">&lt;-</span> copy <span class="Constant">46/period</span>
+<span id="L480" class="LineNr"> 480 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, full-stop, <span class="Constant">245/grey</span>
+<span id="L481" class="LineNr"> 481 </span>  <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> add left,<span class="Constant"> 3</span>
+<span id="L482" class="LineNr"> 482 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L483" class="LineNr"> 483 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># print row</span>
+<span id="L484" class="LineNr"> 484 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> row-done?:bool <span class="Special">&lt;-</span> greater-or-equal column, max-column
+<span id="L485" class="LineNr"> 485 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> row-done?
+<span id="L486" class="LineNr"> 486 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr:<a href='../081print.mu.html#L12'>screen-cell</a> <span class="Special">&lt;-</span> index *buf, i
+<span id="L487" class="LineNr"> 487 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> c:char <span class="Special">&lt;-</span> get curr, <span class="Constant">contents:offset</span>
+<span id="L488" class="LineNr"> 488 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> color:num <span class="Special">&lt;-</span> get curr, <span class="Constant">color:offset</span>
+<span id="L489" class="LineNr"> 489 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L490" class="LineNr"> 490 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># damp whites down to grey</span>
+<span id="L491" class="LineNr"> 491 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> white?:bool <span class="Special">&lt;-</span> equal color, <span class="Constant">7/white</span>
+<span id="L492" class="LineNr"> 492 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> white?
+<span id="L493" class="LineNr"> 493 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> color <span class="Special">&lt;-</span> copy <span class="Constant">245/grey</span>
+<span id="L494" class="LineNr"> 494 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L495" class="LineNr"> 495 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, c, color
+<span id="L496" class="LineNr"> 496 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
+<span id="L497" class="LineNr"> 497 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> i <span class="Special">&lt;-</span> add i,<span class="Constant"> 1</span>
+<span id="L498" class="LineNr"> 498 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span>
+<span id="L499" class="LineNr"> 499 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L500" class="LineNr"> 500 </span>  <span class="Conceal">¦</span> <span class="Comment"># print final '.'</span>
+<span id="L501" class="LineNr"> 501 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, full-stop, <span class="Constant">245/grey</span>
+<span id="L502" class="LineNr"> 502 </span>  <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
+<span id="L503" class="LineNr"> 503 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L504" class="LineNr"> 504 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># clear rest of current line</span>
+<span id="L505" class="LineNr"> 505 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> line-done?:bool <span class="Special">&lt;-</span> greater-than column, right
+<span id="L506" class="LineNr"> 506 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> line-done?
+<span id="L507" class="LineNr"> 507 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, space
+<span id="L508" class="LineNr"> 508 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
+<span id="L509" class="LineNr"> 509 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span>
+<span id="L510" class="LineNr"> 510 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L511" class="LineNr"> 511 </span>  <span class="Conceal">¦</span> row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
+<span id="L512" class="LineNr"> 512 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L513" class="LineNr"> 513 </span>  <span class="Delimiter">}</span>
 <span id="L514" class="LineNr"> 514 </span>]
 <span id="L515" class="LineNr"> 515 </span>
@@ -580,56 +581,56 @@ if ('onhashchange' in window) {
 <span id="L519" class="LineNr"> 519 </span>  assume-screen <span class="Constant">100/width</span>, <span class="Constant">12/height</span>
 <span id="L520" class="LineNr"> 520 </span>  <span class="Comment"># define a recipe (no indent for the 'add' line below so column numbers are more obvious)</span>
 <span id="L521" class="LineNr"> 521 </span>  assume-resources [
-<span id="L522" class="LineNr"> 522 </span>    <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
-<span id="L523" class="LineNr"> 523 </span><span class="Constant">      ||</span>
-<span id="L524" class="LineNr"> 524 </span>      <span class="Constant">|recipe</span> foo <span class="Constant">[|</span>
-<span id="L525" class="LineNr"> 525 </span><span class="Constant">      |  local-scope|</span>
-<span id="L526" class="LineNr"> 526 </span><span class="Constant">      |  z:num &lt;- add 2, 2|</span>
-<span id="L527" class="LineNr"> 527 </span><span class="Constant">      |  reply z|</span>
-<span id="L528" class="LineNr"> 528 </span><span class="Constant">      |]</span>|
-<span id="L529" class="LineNr"> 529 </span>    ]
+<span id="L522" class="LineNr"> 522 </span>  <span class="Conceal">¦</span> <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
+<span id="L523" class="LineNr"> 523 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> ||</span>
+<span id="L524" class="LineNr"> 524 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Constant">|recipe</span> foo <span class="Constant">[|</span>
+<span id="L525" class="LineNr"> 525 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  local-scope|</span>
+<span id="L526" class="LineNr"> 526 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  z:num &lt;- add 2, 2|</span>
+<span id="L527" class="LineNr"> 527 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  reply z|</span>
+<span id="L528" class="LineNr"> 528 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |]</span>|
+<span id="L529" class="LineNr"> 529 </span>  <span class="Conceal">¦</span> ]
 <span id="L530" class="LineNr"> 530 </span>  ]
 <span id="L531" class="LineNr"> 531 </span>  <span class="Comment"># sandbox editor contains an instruction without storing outputs</span>
 <span id="L532" class="LineNr"> 532 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[foo]</span>  <span class="Comment"># contents of sandbox editor</span>
 <span id="L533" class="LineNr"> 533 </span>  <span class="Comment"># run the code in the editors</span>
 <span id="L534" class="LineNr"> 534 </span>  assume-console [
-<span id="L535" class="LineNr"> 535 </span>    press F4
+<span id="L535" class="LineNr"> 535 </span>  <span class="Conceal">¦</span> press F4
 <span id="L536" class="LineNr"> 536 </span>  ]
 <span id="L537" class="LineNr"> 537 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L538" class="LineNr"> 538 </span>  screen-should-contain [
-<span id="L539" class="LineNr"> 539 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L540" class="LineNr"> 540 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L541" class="LineNr"> 541 </span>   <span class="Constant"> .recipe foo [                                      ╎─────────────────────────────────────────────────.</span>
-<span id="L542" class="LineNr"> 542 </span>   <span class="Constant"> .  local-scope                                     ╎0   edit          copy            delete         .</span>
-<span id="L543" class="LineNr"> 543 </span>   <span class="Constant"> .  z:num &lt;- add 2, 2                               ╎foo                                              .</span>
-<span id="L544" class="LineNr"> 544 </span>   <span class="Constant"> .  reply z                                         ╎4                                                .</span>
-<span id="L545" class="LineNr"> 545 </span>   <span class="Constant"> .]                                                 ╎─────────────────────────────────────────────────.</span>
-<span id="L546" class="LineNr"> 546 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L547" class="LineNr"> 547 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
-<span id="L548" class="LineNr"> 548 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L539" class="LineNr"> 539 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L540" class="LineNr"> 540 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L541" class="LineNr"> 541 </span>  <span class="Conceal">¦</span><span class="Constant"> .recipe foo [                                      ╎─────────────────────────────────────────────────.</span>
+<span id="L542" class="LineNr"> 542 </span>  <span class="Conceal">¦</span><span class="Constant"> .  local-scope                                     ╎0   edit          copy            delete         .</span>
+<span id="L543" class="LineNr"> 543 </span>  <span class="Conceal">¦</span><span class="Constant"> .  z:num &lt;- add 2, 2                               ╎foo                                              .</span>
+<span id="L544" class="LineNr"> 544 </span>  <span class="Conceal">¦</span><span class="Constant"> .  reply z                                         ╎4                                                .</span>
+<span id="L545" class="LineNr"> 545 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎─────────────────────────────────────────────────.</span>
+<span id="L546" class="LineNr"> 546 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L547" class="LineNr"> 547 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
+<span id="L548" class="LineNr"> 548 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L549" class="LineNr"> 549 </span>  ]
 <span id="L550" class="LineNr"> 550 </span>  <span class="Comment"># make a change (incrementing one of the args to 'add'), then rerun</span>
 <span id="L551" class="LineNr"> 551 </span>  assume-console [
-<span id="L552" class="LineNr"> 552 </span>    left-click<span class="Constant"> 4</span>,<span class="Constant"> 28</span>  <span class="Comment"># one past the value of the second arg</span>
-<span id="L553" class="LineNr"> 553 </span>    press backspace
-<span id="L554" class="LineNr"> 554 </span>    type <span class="Constant">[3]</span>
-<span id="L555" class="LineNr"> 555 </span>    press F4
+<span id="L552" class="LineNr"> 552 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 4</span>,<span class="Constant"> 28</span>  <span class="Comment"># one past the value of the second arg</span>
+<span id="L553" class="LineNr"> 553 </span>  <span class="Conceal">¦</span> press backspace
+<span id="L554" class="LineNr"> 554 </span>  <span class="Conceal">¦</span> type <span class="Constant">[3]</span>
+<span id="L555" class="LineNr"> 555 </span>  <span class="Conceal">¦</span> press F4
 <span id="L556" class="LineNr"> 556 </span>  ]
 <span id="L557" class="LineNr"> 557 </span>  run [
-<span id="L558" class="LineNr"> 558 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L558" class="LineNr"> 558 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L559" class="LineNr"> 559 </span>  ]
 <span id="L560" class="LineNr"> 560 </span>  <span class="Comment"># check that screen updates the result on the right</span>
 <span id="L561" class="LineNr"> 561 </span>  screen-should-contain [
-<span id="L562" class="LineNr"> 562 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L563" class="LineNr"> 563 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L564" class="LineNr"> 564 </span>   <span class="Constant"> .recipe foo [                                      ╎─────────────────────────────────────────────────.</span>
-<span id="L565" class="LineNr"> 565 </span>   <span class="Constant"> .  local-scope                                     ╎0   edit          copy            delete         .</span>
-<span id="L566" class="LineNr"> 566 </span>   <span class="Constant"> .  z:num &lt;- add 2, 3                               ╎foo                                              .</span>
-<span id="L567" class="LineNr"> 567 </span>   <span class="Constant"> .  reply z                                         ╎5                                                .</span>
-<span id="L568" class="LineNr"> 568 </span>   <span class="Constant"> .]                                                 ╎─────────────────────────────────────────────────.</span>
-<span id="L569" class="LineNr"> 569 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L570" class="LineNr"> 570 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
-<span id="L571" class="LineNr"> 571 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L562" class="LineNr"> 562 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L563" class="LineNr"> 563 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L564" class="LineNr"> 564 </span>  <span class="Conceal">¦</span><span class="Constant"> .recipe foo [                                      ╎─────────────────────────────────────────────────.</span>
+<span id="L565" class="LineNr"> 565 </span>  <span class="Conceal">¦</span><span class="Constant"> .  local-scope                                     ╎0   edit          copy            delete         .</span>
+<span id="L566" class="LineNr"> 566 </span>  <span class="Conceal">¦</span><span class="Constant"> .  z:num &lt;- add 2, 3                               ╎foo                                              .</span>
+<span id="L567" class="LineNr"> 567 </span>  <span class="Conceal">¦</span><span class="Constant"> .  reply z                                         ╎5                                                .</span>
+<span id="L568" class="LineNr"> 568 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎─────────────────────────────────────────────────.</span>
+<span id="L569" class="LineNr"> 569 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L570" class="LineNr"> 570 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
+<span id="L571" class="LineNr"> 571 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L572" class="LineNr"> 572 </span>  ]
 <span id="L573" class="LineNr"> 573 </span>]
 <span id="L574" class="LineNr"> 574 </span>
@@ -644,26 +645,26 @@ if ('onhashchange' in window) {
 <span id="L583" class="LineNr"> 583 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[print <a href='../081print.mu.html#L4'>screen</a>, 4]</span>  <span class="Comment"># contents of sandbox editor</span>
 <span id="L584" class="LineNr"> 584 </span>  <span class="Comment"># run the code in the editor</span>
 <span id="L585" class="LineNr"> 585 </span>  assume-console [
-<span id="L586" class="LineNr"> 586 </span>    press F4
+<span id="L586" class="LineNr"> 586 </span>  <span class="Conceal">¦</span> press F4
 <span id="L587" class="LineNr"> 587 </span>  ]
 <span id="L588" class="LineNr"> 588 </span>  run [
-<span id="L589" class="LineNr"> 589 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L589" class="LineNr"> 589 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L590" class="LineNr"> 590 </span>  ]
 <span id="L591" class="LineNr"> 591 </span>  <span class="Comment"># check that it prints a little toy screen</span>
 <span id="L592" class="LineNr"> 592 </span>  screen-should-contain [
-<span id="L593" class="LineNr"> 593 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L594" class="LineNr"> 594 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L595" class="LineNr"> 595 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L596" class="LineNr"> 596 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L597" class="LineNr"> 597 </span>   <span class="Constant"> .                                                  ╎print <a href='../081print.mu.html#L4'>screen</a>, 4                                  .</span>
-<span id="L598" class="LineNr"> 598 </span>   <span class="Constant"> .                                                  ╎screen:                                          .</span>
-<span id="L599" class="LineNr"> 599 </span>   <span class="Constant"> .                                                  ╎  .4                             .               .</span>
-<span id="L600" class="LineNr"> 600 </span>   <span class="Constant"> .                                                  ╎  .                              .               .</span>
-<span id="L601" class="LineNr"> 601 </span>   <span class="Constant"> .                                                  ╎  .                              .               .</span>
-<span id="L602" class="LineNr"> 602 </span>   <span class="Constant"> .                                                  ╎  .                              .               .</span>
-<span id="L603" class="LineNr"> 603 </span>   <span class="Constant"> .                                                  ╎  .                              .               .</span>
-<span id="L604" class="LineNr"> 604 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L605" class="LineNr"> 605 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L593" class="LineNr"> 593 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L594" class="LineNr"> 594 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L595" class="LineNr"> 595 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L596" class="LineNr"> 596 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L597" class="LineNr"> 597 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎print <a href='../081print.mu.html#L4'>screen</a>, 4                                  .</span>
+<span id="L598" class="LineNr"> 598 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎screen:                                          .</span>
+<span id="L599" class="LineNr"> 599 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎  .4                             .               .</span>
+<span id="L600" class="LineNr"> 600 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎  .                              .               .</span>
+<span id="L601" class="LineNr"> 601 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎  .                              .               .</span>
+<span id="L602" class="LineNr"> 602 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎  .                              .               .</span>
+<span id="L603" class="LineNr"> 603 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎  .                              .               .</span>
+<span id="L604" class="LineNr"> 604 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L605" class="LineNr"> 605 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L606" class="LineNr"> 606 </span>  ]
 <span id="L607" class="LineNr"> 607 </span>]
 <span id="L608" class="LineNr"> 608 </span>
@@ -677,11 +678,11 @@ if ('onhashchange' in window) {
 <span id="L616" class="LineNr"> 616 </span>  curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
 <span id="L617" class="LineNr"> 617 </span>  <span class="muControl">return-unless</span> curr,<span class="Constant"> 0</span>
 <span id="L618" class="LineNr"> 618 </span>  <span class="Delimiter">{</span>
-<span id="L619" class="LineNr"> 619 </span>    <span class="muControl">break-unless</span> curr
-<span id="L620" class="LineNr"> 620 </span>    c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
-<span id="L621" class="LineNr"> 621 </span>    buf <span class="Special">&lt;-</span> append buf, c
-<span id="L622" class="LineNr"> 622 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
-<span id="L623" class="LineNr"> 623 </span>    <span class="muControl">loop</span>
+<span id="L619" class="LineNr"> 619 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> curr
+<span id="L620" class="LineNr"> 620 </span>  <span class="Conceal">¦</span> c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
+<span id="L621" class="LineNr"> 621 </span>  <span class="Conceal">¦</span> buf <span class="Special">&lt;-</span> append buf, c
+<span id="L622" class="LineNr"> 622 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L623" class="LineNr"> 623 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L624" class="LineNr"> 624 </span>  <span class="Delimiter">}</span>
 <span id="L625" class="LineNr"> 625 </span>  result <span class="Special">&lt;-</span> <a href='../061text.mu.html#L329'>buffer-to-array</a> buf
 <span id="L626" class="LineNr"> 626 </span>]
@@ -691,16 +692,16 @@ if ('onhashchange' in window) {
 <span id="L630" class="LineNr"> 630 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
 <span id="L631" class="LineNr"> 631 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> <span class="Constant">[abc]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L632" class="LineNr"> 632 </span>  assume-console [
-<span id="L633" class="LineNr"> 633 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 2</span>
-<span id="L634" class="LineNr"> 634 </span>    type <span class="Constant">[def]</span>
+<span id="L633" class="LineNr"> 633 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 2</span>
+<span id="L634" class="LineNr"> 634 </span>  <span class="Conceal">¦</span> type <span class="Constant">[def]</span>
 <span id="L635" class="LineNr"> 635 </span>  ]
 <span id="L636" class="LineNr"> 636 </span>  run [
-<span id="L637" class="LineNr"> 637 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L638" class="LineNr"> 638 </span>    s:text <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L609'>editor-contents</a> e
-<span id="L639" class="LineNr"> 639 </span>    1:@:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> copy *s
+<span id="L637" class="LineNr"> 637 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L638" class="LineNr"> 638 </span>  <span class="Conceal">¦</span> s:text <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L609'>editor-contents</a> e
+<span id="L639" class="LineNr"> 639 </span>  <span class="Conceal">¦</span> 1:@:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> copy *s
 <span id="L640" class="LineNr"> 640 </span>  ]
 <span id="L641" class="LineNr"> 641 </span>  memory-should-contain [
-<span id="L642" class="LineNr"> 642 </span>    1:array:character <span class="Special">&lt;-</span> <span class="Constant">[abdefc]</span>
+<span id="L642" class="LineNr"> 642 </span>  <span class="Conceal">¦</span> 1:array:character <span class="Special">&lt;-</span> <span class="Constant">[abdefc]</span>
 <span id="L643" class="LineNr"> 643 </span>  ]
 <span id="L644" class="LineNr"> 644 </span>]
 <span id="L645" class="LineNr"> 645 </span>
@@ -715,17 +716,17 @@ if ('onhashchange' in window) {
 <span id="L654" class="LineNr"> 654 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[]</span>
 <span id="L655" class="LineNr"> 655 </span>  <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
 <span id="L656" class="LineNr"> 656 </span>  assume-console [
-<span id="L657" class="LineNr"> 657 </span>    press enter
-<span id="L658" class="LineNr"> 658 </span>    press down-arrow
+<span id="L657" class="LineNr"> 657 </span>  <span class="Conceal">¦</span> press enter
+<span id="L658" class="LineNr"> 658 </span>  <span class="Conceal">¦</span> press down-arrow
 <span id="L659" class="LineNr"> 659 </span>  ]
 <span id="L660" class="LineNr"> 660 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L661" class="LineNr"> 661 </span>  <span class="Comment"># no scroll</span>
 <span id="L662" class="LineNr"> 662 </span>  screen-should-contain [
-<span id="L663" class="LineNr"> 663 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L664" class="LineNr"> 664 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L665" class="LineNr"> 665 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L666" class="LineNr"> 666 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
-<span id="L667" class="LineNr"> 667 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L663" class="LineNr"> 663 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L664" class="LineNr"> 664 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L665" class="LineNr"> 665 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L666" class="LineNr"> 666 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
+<span id="L667" class="LineNr"> 667 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L668" class="LineNr"> 668 </span>  ]
 <span id="L669" class="LineNr"> 669 </span>]
 <span id="L670" class="LineNr"> 670 </span>
@@ -738,20 +739,20 @@ if ('onhashchange' in window) {
 <span id="L677" class="LineNr"> 677 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[]</span>
 <span id="L678" class="LineNr"> 678 </span>  <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
 <span id="L679" class="LineNr"> 679 </span>  assume-console [
-<span id="L680" class="LineNr"> 680 </span>    press enter
-<span id="L681" class="LineNr"> 681 </span>    press up-arrow
-<span id="L682" class="LineNr"> 682 </span>    press down-arrow  <span class="Comment"># while cursor isn't at bottom</span>
+<span id="L680" class="LineNr"> 680 </span>  <span class="Conceal">¦</span> press enter
+<span id="L681" class="LineNr"> 681 </span>  <span class="Conceal">¦</span> press up-arrow
+<span id="L682" class="LineNr"> 682 </span>  <span class="Conceal">¦</span> press down-arrow  <span class="Comment"># while cursor isn't at bottom</span>
 <span id="L683" class="LineNr"> 683 </span>  ]
 <span id="L684" class="LineNr"> 684 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L685" class="LineNr"> 685 </span>  cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
 <span id="L686" class="LineNr"> 686 </span>  print <a href='../081print.mu.html#L4'>screen</a>, cursor
 <span id="L687" class="LineNr"> 687 </span>  <span class="Comment"># cursor moves back to bottom</span>
 <span id="L688" class="LineNr"> 688 </span>  screen-should-contain [
-<span id="L689" class="LineNr"> 689 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L690" class="LineNr"> 690 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L691" class="LineNr"> 691 </span>   <span class="Constant"> .␣                                                 ╎─────────────────────────────────────────────────.</span>
-<span id="L692" class="LineNr"> 692 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
-<span id="L693" class="LineNr"> 693 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L689" class="LineNr"> 689 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L690" class="LineNr"> 690 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L691" class="LineNr"> 691 </span>  <span class="Conceal">¦</span><span class="Constant"> .␣                                                 ╎─────────────────────────────────────────────────.</span>
+<span id="L692" class="LineNr"> 692 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
+<span id="L693" class="LineNr"> 693 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L694" class="LineNr"> 694 </span>  ]
 <span id="L695" class="LineNr"> 695 </span>]
 <span id="L696" class="LineNr"> 696 </span>
@@ -768,36 +769,36 @@ if ('onhashchange' in window) {
 <span id="L707" class="LineNr"> 707 </span>
 <span id="L708" class="LineNr"> 708 </span><span class="muRecipe">after</span> <span class="Constant"><a href='004-programming-environment.mu.html#L61'>&lt;global-keypress&gt;</a></span> [
 <span id="L709" class="LineNr"> 709 </span>  <span class="Delimiter">{</span>
-<span id="L710" class="LineNr"> 710 </span>    <span class="muControl">break-if</span> sandbox-in-focus?
-<span id="L711" class="LineNr"> 711 </span>    down-arrow?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65516/down-arrow</span>
-<span id="L712" class="LineNr"> 712 </span>    <span class="muControl">break-unless</span> down-arrow?
-<span id="L713" class="LineNr"> 713 </span>    recipe-editor:&amp;:editor <span class="Special">&lt;-</span> get *env, <span class="Constant">recipes:offset</span>
-<span id="L714" class="LineNr"> 714 </span>    recipe-cursor-row:num <span class="Special">&lt;-</span> get *recipe-editor, <span class="Constant">cursor-row:offset</span>
-<span id="L715" class="LineNr"> 715 </span>    recipe-editor-bottom:num <span class="Special">&lt;-</span> get *recipe-editor, <span class="Constant">bottom:offset</span>
-<span id="L716" class="LineNr"> 716 </span>    at-bottom-of-editor?:bool <span class="Special">&lt;-</span> greater-or-equal recipe-cursor-row, recipe-editor-bottom
-<span id="L717" class="LineNr"> 717 </span>    <span class="muControl">break-unless</span> at-bottom-of-editor?
-<span id="L718" class="LineNr"> 718 </span>    <a href='005-sandbox.mu.html#L743'>more-to-scroll?</a>:bool <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L743'>more-to-scroll?</a> env, <a href='../081print.mu.html#L4'>screen</a>
-<span id="L719" class="LineNr"> 719 </span>    <span class="muControl">break-if</span> <a href='005-sandbox.mu.html#L743'>more-to-scroll?</a>
-<span id="L720" class="LineNr"> 720 </span>    <span class="muControl">loop</span> <span class="Constant">+next-event</span>
+<span id="L710" class="LineNr"> 710 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> sandbox-in-focus?
+<span id="L711" class="LineNr"> 711 </span>  <span class="Conceal">¦</span> down-arrow?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65516/down-arrow</span>
+<span id="L712" class="LineNr"> 712 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> down-arrow?
+<span id="L713" class="LineNr"> 713 </span>  <span class="Conceal">¦</span> recipe-editor:&amp;:editor <span class="Special">&lt;-</span> get *env, <span class="Constant">recipes:offset</span>
+<span id="L714" class="LineNr"> 714 </span>  <span class="Conceal">¦</span> recipe-cursor-row:num <span class="Special">&lt;-</span> get *recipe-editor, <span class="Constant">cursor-row:offset</span>
+<span id="L715" class="LineNr"> 715 </span>  <span class="Conceal">¦</span> recipe-editor-bottom:num <span class="Special">&lt;-</span> get *recipe-editor, <span class="Constant">bottom:offset</span>
+<span id="L716" class="LineNr"> 716 </span>  <span class="Conceal">¦</span> at-bottom-of-editor?:bool <span class="Special">&lt;-</span> greater-or-equal recipe-cursor-row, recipe-editor-bottom
+<span id="L717" class="LineNr"> 717 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-bottom-of-editor?
+<span id="L718" class="LineNr"> 718 </span>  <span class="Conceal">¦</span> <a href='005-sandbox.mu.html#L743'>more-to-scroll?</a>:bool <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L743'>more-to-scroll?</a> env, <a href='../081print.mu.html#L4'>screen</a>
+<span id="L719" class="LineNr"> 719 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> <a href='005-sandbox.mu.html#L743'>more-to-scroll?</a>
+<span id="L720" class="LineNr"> 720 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-event</span>
 <span id="L721" class="LineNr"> 721 </span>  <span class="Delimiter">}</span>
 <span id="L722" class="LineNr"> 722 </span>  <span class="Delimiter">{</span>
-<span id="L723" class="LineNr"> 723 </span>    <span class="muControl">break-if</span> sandbox-in-focus?
-<span id="L724" class="LineNr"> 724 </span>    page-down?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65518/page-down</span>
-<span id="L725" class="LineNr"> 725 </span>    <span class="muControl">break-unless</span> page-down?
-<span id="L726" class="LineNr"> 726 </span>    <a href='005-sandbox.mu.html#L743'>more-to-scroll?</a>:bool <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L743'>more-to-scroll?</a> env, <a href='../081print.mu.html#L4'>screen</a>
-<span id="L727" class="LineNr"> 727 </span>    <span class="muControl">break-if</span> <a href='005-sandbox.mu.html#L743'>more-to-scroll?</a>
-<span id="L728" class="LineNr"> 728 </span>    <span class="muControl">loop</span> <span class="Constant">+next-event</span>
+<span id="L723" class="LineNr"> 723 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> sandbox-in-focus?
+<span id="L724" class="LineNr"> 724 </span>  <span class="Conceal">¦</span> page-down?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65518/page-down</span>
+<span id="L725" class="LineNr"> 725 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> page-down?
+<span id="L726" class="LineNr"> 726 </span>  <span class="Conceal">¦</span> <a href='005-sandbox.mu.html#L743'>more-to-scroll?</a>:bool <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L743'>more-to-scroll?</a> env, <a href='../081print.mu.html#L4'>screen</a>
+<span id="L727" class="LineNr"> 727 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> <a href='005-sandbox.mu.html#L743'>more-to-scroll?</a>
+<span id="L728" class="LineNr"> 728 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-event</span>
 <span id="L729" class="LineNr"> 729 </span>  <span class="Delimiter">}</span>
 <span id="L730" class="LineNr"> 730 </span>]
 <span id="L731" class="LineNr"> 731 </span>
 <span id="L732" class="LineNr"> 732 </span><span class="muRecipe">after</span> <span class="Constant"><a href='004-programming-environment.mu.html#L66'>&lt;global-type&gt;</a></span> [
 <span id="L733" class="LineNr"> 733 </span>  <span class="Delimiter">{</span>
-<span id="L734" class="LineNr"> 734 </span>    <span class="muControl">break-if</span> sandbox-in-focus?
-<span id="L735" class="LineNr"> 735 </span>    page-down?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">6/ctrl-f</span>
-<span id="L736" class="LineNr"> 736 </span>    <span class="muControl">break-unless</span> page-down?
-<span id="L737" class="LineNr"> 737 </span>    <a href='005-sandbox.mu.html#L743'>more-to-scroll?</a>:bool <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L743'>more-to-scroll?</a> env, <a href='../081print.mu.html#L4'>screen</a>
-<span id="L738" class="LineNr"> 738 </span>    <span class="muControl">break-if</span> <a href='005-sandbox.mu.html#L743'>more-to-scroll?</a>
-<span id="L739" class="LineNr"> 739 </span>    <span class="muControl">loop</span> <span class="Constant">+next-event</span>
+<span id="L734" class="LineNr"> 734 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> sandbox-in-focus?
+<span id="L735" class="LineNr"> 735 </span>  <span class="Conceal">¦</span> page-down?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">6/ctrl-f</span>
+<span id="L736" class="LineNr"> 736 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> page-down?
+<span id="L737" class="LineNr"> 737 </span>  <span class="Conceal">¦</span> <a href='005-sandbox.mu.html#L743'>more-to-scroll?</a>:bool <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L743'>more-to-scroll?</a> env, <a href='../081print.mu.html#L4'>screen</a>
+<span id="L738" class="LineNr"> 738 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> <a href='005-sandbox.mu.html#L743'>more-to-scroll?</a>
+<span id="L739" class="LineNr"> 739 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-event</span>
 <span id="L740" class="LineNr"> 740 </span>  <span class="Delimiter">}</span>
 <span id="L741" class="LineNr"> 741 </span>]
 <span id="L742" class="LineNr"> 742 </span>
@@ -818,21 +819,21 @@ if ('onhashchange' in window) {
 <span id="L757" class="LineNr"> 757 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[]</span>
 <span id="L758" class="LineNr"> 758 </span>  <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
 <span id="L759" class="LineNr"> 759 </span>  assume-console [
-<span id="L760" class="LineNr"> 760 </span>    <span class="Comment"># add a line</span>
-<span id="L761" class="LineNr"> 761 </span>    press enter
-<span id="L762" class="LineNr"> 762 </span>    <span class="Comment"># cursor back to top line</span>
-<span id="L763" class="LineNr"> 763 </span>    press up-arrow
-<span id="L764" class="LineNr"> 764 </span>    <span class="Comment"># try to scroll</span>
-<span id="L765" class="LineNr"> 765 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>  <span class="Comment"># or ctrl-f</span>
+<span id="L760" class="LineNr"> 760 </span>  <span class="Conceal">¦</span> <span class="Comment"># add a line</span>
+<span id="L761" class="LineNr"> 761 </span>  <span class="Conceal">¦</span> press enter
+<span id="L762" class="LineNr"> 762 </span>  <span class="Conceal">¦</span> <span class="Comment"># cursor back to top line</span>
+<span id="L763" class="LineNr"> 763 </span>  <span class="Conceal">¦</span> press up-arrow
+<span id="L764" class="LineNr"> 764 </span>  <span class="Conceal">¦</span> <span class="Comment"># try to scroll</span>
+<span id="L765" class="LineNr"> 765 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>  <span class="Comment"># or ctrl-f</span>
 <span id="L766" class="LineNr"> 766 </span>  ]
 <span id="L767" class="LineNr"> 767 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L768" class="LineNr"> 768 </span>  <span class="Comment"># no scroll, and cursor remains at top line</span>
 <span id="L769" class="LineNr"> 769 </span>  screen-should-contain [
-<span id="L770" class="LineNr"> 770 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L771" class="LineNr"> 771 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L772" class="LineNr"> 772 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L773" class="LineNr"> 773 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
-<span id="L774" class="LineNr"> 774 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L770" class="LineNr"> 770 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L771" class="LineNr"> 771 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L772" class="LineNr"> 772 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L773" class="LineNr"> 773 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
+<span id="L774" class="LineNr"> 774 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L775" class="LineNr"> 775 </span>  ]
 <span id="L776" class="LineNr"> 776 </span>]
 <span id="L777" class="LineNr"> 777 </span>
@@ -846,23 +847,23 @@ if ('onhashchange' in window) {
 <span id="L785" class="LineNr"> 785 </span><span class="Constant">cd]</span>
 <span id="L786" class="LineNr"> 786 </span>  <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
 <span id="L787" class="LineNr"> 787 </span>  assume-console [
-<span id="L788" class="LineNr"> 788 </span>    <span class="Comment"># add a line</span>
-<span id="L789" class="LineNr"> 789 </span>    press enter
-<span id="L790" class="LineNr"> 790 </span>    <span class="Comment"># switch to sandbox</span>
-<span id="L791" class="LineNr"> 791 </span>    press ctrl-n
-<span id="L792" class="LineNr"> 792 </span>    <span class="Comment"># move cursor</span>
-<span id="L793" class="LineNr"> 793 </span>    press down-arrow
+<span id="L788" class="LineNr"> 788 </span>  <span class="Conceal">¦</span> <span class="Comment"># add a line</span>
+<span id="L789" class="LineNr"> 789 </span>  <span class="Conceal">¦</span> press enter
+<span id="L790" class="LineNr"> 790 </span>  <span class="Conceal">¦</span> <span class="Comment"># switch to sandbox</span>
+<span id="L791" class="LineNr"> 791 </span>  <span class="Conceal">¦</span> press ctrl-n
+<span id="L792" class="LineNr"> 792 </span>  <span class="Conceal">¦</span> <span class="Comment"># move cursor</span>
+<span id="L793" class="LineNr"> 793 </span>  <span class="Conceal">¦</span> press down-arrow
 <span id="L794" class="LineNr"> 794 </span>  ]
 <span id="L795" class="LineNr"> 795 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L796" class="LineNr"> 796 </span>  cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
 <span id="L797" class="LineNr"> 797 </span>  print <a href='../081print.mu.html#L4'>screen</a>, cursor
 <span id="L798" class="LineNr"> 798 </span>  <span class="Comment"># no scroll on recipe side, cursor moves on sandbox side</span>
 <span id="L799" class="LineNr"> 799 </span>  screen-should-contain [
-<span id="L800" class="LineNr"> 800 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L801" class="LineNr"> 801 </span>   <span class="Constant"> .                                                  ╎ab                                               .</span>
-<span id="L802" class="LineNr"> 802 </span>   <span class="Constant"> .                                                  ╎␣d                                               .</span>
-<span id="L803" class="LineNr"> 803 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L804" class="LineNr"> 804 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L800" class="LineNr"> 800 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L801" class="LineNr"> 801 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎ab                                               .</span>
+<span id="L802" class="LineNr"> 802 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎␣d                                               .</span>
+<span id="L803" class="LineNr"> 803 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L804" class="LineNr"> 804 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L805" class="LineNr"> 805 </span>  ]
 <span id="L806" class="LineNr"> 806 </span>]
 <span id="L807" class="LineNr"> 807 </span>
@@ -878,108 +879,108 @@ if ('onhashchange' in window) {
 <span id="L817" class="LineNr"> 817 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[add 2, 2]</span>
 <span id="L818" class="LineNr"> 818 </span>  <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
 <span id="L819" class="LineNr"> 819 </span>  assume-console [
-<span id="L820" class="LineNr"> 820 </span>    <span class="Comment"># create a sandbox</span>
-<span id="L821" class="LineNr"> 821 </span>    press F4
+<span id="L820" class="LineNr"> 820 </span>  <span class="Conceal">¦</span> <span class="Comment"># create a sandbox</span>
+<span id="L821" class="LineNr"> 821 </span>  <span class="Conceal">¦</span> press F4
 <span id="L822" class="LineNr"> 822 </span>  ]
 <span id="L823" class="LineNr"> 823 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L824" class="LineNr"> 824 </span>  screen-should-contain [
-<span id="L825" class="LineNr"> 825 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L826" class="LineNr"> 826 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L827" class="LineNr"> 827 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L828" class="LineNr"> 828 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L829" class="LineNr"> 829 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L825" class="LineNr"> 825 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L826" class="LineNr"> 826 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L827" class="LineNr"> 827 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L828" class="LineNr"> 828 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L829" class="LineNr"> 829 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
 <span id="L830" class="LineNr"> 830 </span>  ]
 <span id="L831" class="LineNr"> 831 </span>  <span class="Comment"># switch to sandbox window and hit 'page-down'</span>
 <span id="L832" class="LineNr"> 832 </span>  assume-console [
-<span id="L833" class="LineNr"> 833 </span>    press ctrl-n
-<span id="L834" class="LineNr"> 834 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L833" class="LineNr"> 833 </span>  <span class="Conceal">¦</span> press ctrl-n
+<span id="L834" class="LineNr"> 834 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L835" class="LineNr"> 835 </span>  ]
 <span id="L836" class="LineNr"> 836 </span>  run [
-<span id="L837" class="LineNr"> 837 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
-<span id="L838" class="LineNr"> 838 </span>    cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
-<span id="L839" class="LineNr"> 839 </span>    print <a href='../081print.mu.html#L4'>screen</a>, cursor
+<span id="L837" class="LineNr"> 837 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L838" class="LineNr"> 838 </span>  <span class="Conceal">¦</span> cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
+<span id="L839" class="LineNr"> 839 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, cursor
 <span id="L840" class="LineNr"> 840 </span>  ]
 <span id="L841" class="LineNr"> 841 </span>  <span class="Comment"># sandbox editor hidden; first sandbox displayed</span>
 <span id="L842" class="LineNr"> 842 </span>  <span class="Comment"># cursor moves to first sandbox</span>
 <span id="L843" class="LineNr"> 843 </span>  screen-should-contain [
-<span id="L844" class="LineNr"> 844 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L845" class="LineNr"> 845 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L846" class="LineNr"> 846 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎␣   edit          copy            delete         .</span>
-<span id="L847" class="LineNr"> 847 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L848" class="LineNr"> 848 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L844" class="LineNr"> 844 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L845" class="LineNr"> 845 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L846" class="LineNr"> 846 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎␣   edit          copy            delete         .</span>
+<span id="L847" class="LineNr"> 847 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L848" class="LineNr"> 848 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
 <span id="L849" class="LineNr"> 849 </span>  ]
 <span id="L850" class="LineNr"> 850 </span>  <span class="Comment"># hit 'page-up'</span>
 <span id="L851" class="LineNr"> 851 </span>  assume-console [
-<span id="L852" class="LineNr"> 852 </span>    press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
+<span id="L852" class="LineNr"> 852 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
 <span id="L853" class="LineNr"> 853 </span>  ]
 <span id="L854" class="LineNr"> 854 </span>  run [
-<span id="L855" class="LineNr"> 855 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
-<span id="L856" class="LineNr"> 856 </span>    cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
-<span id="L857" class="LineNr"> 857 </span>    print <a href='../081print.mu.html#L4'>screen</a>, cursor
+<span id="L855" class="LineNr"> 855 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L856" class="LineNr"> 856 </span>  <span class="Conceal">¦</span> cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
+<span id="L857" class="LineNr"> 857 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, cursor
 <span id="L858" class="LineNr"> 858 </span>  ]
 <span id="L859" class="LineNr"> 859 </span>  <span class="Comment"># sandbox editor displays again, cursor is in editor</span>
 <span id="L860" class="LineNr"> 860 </span>  screen-should-contain [
-<span id="L861" class="LineNr"> 861 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L862" class="LineNr"> 862 </span>   <span class="Constant"> .                                                  ╎␣                                                .</span>
-<span id="L863" class="LineNr"> 863 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L864" class="LineNr"> 864 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L865" class="LineNr"> 865 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L861" class="LineNr"> 861 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L862" class="LineNr"> 862 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎␣                                                .</span>
+<span id="L863" class="LineNr"> 863 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L864" class="LineNr"> 864 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L865" class="LineNr"> 865 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
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 <span id="L867" class="LineNr"> 867 </span>]
 <span id="L868" class="LineNr"> 868 </span>
 <span id="L869" class="LineNr"> 869 </span><span class="Comment"># page-down on sandbox side updates render-from to scroll sandboxes</span>
 <span id="L870" class="LineNr"> 870 </span><span class="muRecipe">after</span> <span class="Constant"><a href='004-programming-environment.mu.html#L61'>&lt;global-keypress&gt;</a></span> [
 <span id="L871" class="LineNr"> 871 </span>  <span class="Delimiter">{</span>
-<span id="L872" class="LineNr"> 872 </span>    <span class="muControl">break-unless</span> sandbox-in-focus?
-<span id="L873" class="LineNr"> 873 </span>    page-down?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65518/page-down</span>
-<span id="L874" class="LineNr"> 874 </span>    <span class="muControl">break-unless</span> page-down?
-<span id="L875" class="LineNr"> 875 </span>    sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *env, <span class="Constant">sandbox:offset</span>
-<span id="L876" class="LineNr"> 876 </span>    <span class="muControl">break-unless</span> sandbox
-<span id="L877" class="LineNr"> 877 </span>    <span class="Comment"># slide down if possible</span>
-<span id="L878" class="LineNr"> 878 </span>    <span class="Delimiter">{</span>
-<span id="L879" class="LineNr"> 879 </span>      render-from:num <span class="Special">&lt;-</span> get *env, <span class="Constant">render-from:offset</span>
-<span id="L880" class="LineNr"> 880 </span>      number-of-sandboxes:num <span class="Special">&lt;-</span> get *env, <span class="Constant">number-of-sandboxes:offset</span>
-<span id="L881" class="LineNr"> 881 </span>      max:num <span class="Special">&lt;-</span> subtract number-of-sandboxes,<span class="Constant"> 1</span>
-<span id="L882" class="LineNr"> 882 </span>      at-end?:bool <span class="Special">&lt;-</span> greater-or-equal render-from, max
-<span id="L883" class="LineNr"> 883 </span>      <span class="muControl">jump-if</span> at-end?, <span class="Constant">+finish-event</span>  <span class="Comment"># render nothing</span>
-<span id="L884" class="LineNr"> 884 </span>      render-from <span class="Special">&lt;-</span> add render-from,<span class="Constant"> 1</span>
-<span id="L885" class="LineNr"> 885 </span>      *env <span class="Special">&lt;-</span> put *env, <span class="Constant">render-from:offset</span>, render-from
-<span id="L886" class="LineNr"> 886 </span>    <span class="Delimiter">}</span>
-<span id="L887" class="LineNr"> 887 </span>    <a href='../081print.mu.html#L623'>hide-screen</a> <a href='../081print.mu.html#L4'>screen</a>
-<span id="L888" class="LineNr"> 888 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> render-sandbox-side <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
-<span id="L889" class="LineNr"> 889 </span>    <a href='../081print.mu.html#L631'>show-screen</a> <a href='../081print.mu.html#L4'>screen</a>
-<span id="L890" class="LineNr"> 890 </span>    <span class="muControl">jump</span> <span class="Constant">+finish-event</span>
+<span id="L872" class="LineNr"> 872 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> sandbox-in-focus?
+<span id="L873" class="LineNr"> 873 </span>  <span class="Conceal">¦</span> page-down?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65518/page-down</span>
+<span id="L874" class="LineNr"> 874 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> page-down?
+<span id="L875" class="LineNr"> 875 </span>  <span class="Conceal">¦</span> sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *env, <span class="Constant">sandbox:offset</span>
+<span id="L876" class="LineNr"> 876 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> sandbox
+<span id="L877" class="LineNr"> 877 </span>  <span class="Conceal">¦</span> <span class="Comment"># slide down if possible</span>
+<span id="L878" class="LineNr"> 878 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L879" class="LineNr"> 879 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> render-from:num <span class="Special">&lt;-</span> get *env, <span class="Constant">render-from:offset</span>
+<span id="L880" class="LineNr"> 880 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> number-of-sandboxes:num <span class="Special">&lt;-</span> get *env, <span class="Constant">number-of-sandboxes:offset</span>
+<span id="L881" class="LineNr"> 881 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> max:num <span class="Special">&lt;-</span> subtract number-of-sandboxes,<span class="Constant"> 1</span>
+<span id="L882" class="LineNr"> 882 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-end?:bool <span class="Special">&lt;-</span> greater-or-equal render-from, max
+<span id="L883" class="LineNr"> 883 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">jump-if</span> at-end?, <span class="Constant">+finish-event</span>  <span class="Comment"># render nothing</span>
+<span id="L884" class="LineNr"> 884 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> render-from <span class="Special">&lt;-</span> add render-from,<span class="Constant"> 1</span>
+<span id="L885" class="LineNr"> 885 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> *env <span class="Special">&lt;-</span> put *env, <span class="Constant">render-from:offset</span>, render-from
+<span id="L886" class="LineNr"> 886 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L887" class="LineNr"> 887 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L623'>hide-screen</a> <a href='../081print.mu.html#L4'>screen</a>
+<span id="L888" class="LineNr"> 888 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> render-sandbox-side <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
+<span id="L889" class="LineNr"> 889 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L631'>show-screen</a> <a href='../081print.mu.html#L4'>screen</a>
+<span id="L890" class="LineNr"> 890 </span>  <span class="Conceal">¦</span> <span class="muControl">jump</span> <span class="Constant">+finish-event</span>
 <span id="L891" class="LineNr"> 891 </span>  <span class="Delimiter">}</span>
 <span id="L892" class="LineNr"> 892 </span>]
 <span id="L893" class="LineNr"> 893 </span>
 <span id="L894" class="LineNr"> 894 </span><span class="Comment"># update-cursor takes render-from into account</span>
 <span id="L895" class="LineNr"> 895 </span><span class="muRecipe">after</span> <span class="Constant"><a href='004-programming-environment.mu.html#L514'>&lt;update-cursor-special-cases&gt;</a></span> [
 <span id="L896" class="LineNr"> 896 </span>  <span class="Delimiter">{</span>
-<span id="L897" class="LineNr"> 897 </span>    <span class="muControl">break-unless</span> sandbox-in-focus?
-<span id="L898" class="LineNr"> 898 </span>    render-from:num <span class="Special">&lt;-</span> get *env, <span class="Constant">render-from:offset</span>
-<span id="L899" class="LineNr"> 899 </span>    scrolling?:bool <span class="Special">&lt;-</span> greater-or-equal render-from,<span class="Constant"> 0</span>
-<span id="L900" class="LineNr"> 900 </span>    <span class="muControl">break-unless</span> scrolling?
-<span id="L901" class="LineNr"> 901 </span>    cursor-column:num <span class="Special">&lt;-</span> get *current-sandbox, <span class="Constant">left:offset</span>
-<span id="L902" class="LineNr"> 902 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">2/row</span>, cursor-column  <span class="Comment"># highlighted sandbox will always start at row 2</span>
-<span id="L903" class="LineNr"> 903 </span>    <span class="muControl">return</span>
+<span id="L897" class="LineNr"> 897 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> sandbox-in-focus?
+<span id="L898" class="LineNr"> 898 </span>  <span class="Conceal">¦</span> render-from:num <span class="Special">&lt;-</span> get *env, <span class="Constant">render-from:offset</span>
+<span id="L899" class="LineNr"> 899 </span>  <span class="Conceal">¦</span> scrolling?:bool <span class="Special">&lt;-</span> greater-or-equal render-from,<span class="Constant"> 0</span>
+<span id="L900" class="LineNr"> 900 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> scrolling?
+<span id="L901" class="LineNr"> 901 </span>  <span class="Conceal">¦</span> cursor-column:num <span class="Special">&lt;-</span> get *current-sandbox, <span class="Constant">left:offset</span>
+<span id="L902" class="LineNr"> 902 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='../081print.mu.html#L442'>move-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">2/row</span>, cursor-column  <span class="Comment"># highlighted sandbox will always start at row 2</span>
+<span id="L903" class="LineNr"> 903 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
 <span id="L904" class="LineNr"> 904 </span>  <span class="Delimiter">}</span>
 <span id="L905" class="LineNr"> 905 </span>]
 <span id="L906" class="LineNr"> 906 </span>
 <span id="L907" class="LineNr"> 907 </span><span class="Comment"># 'page-up' on sandbox side is like 'page-down': updates render-from when necessary</span>
 <span id="L908" class="LineNr"> 908 </span><span class="muRecipe">after</span> <span class="Constant"><a href='004-programming-environment.mu.html#L61'>&lt;global-keypress&gt;</a></span> [
 <span id="L909" class="LineNr"> 909 </span>  <span class="Delimiter">{</span>
-<span id="L910" class="LineNr"> 910 </span>    <span class="muControl">break-unless</span> sandbox-in-focus?
-<span id="L911" class="LineNr"> 911 </span>    page-up?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65519/page-up</span>
-<span id="L912" class="LineNr"> 912 </span>    <span class="muControl">break-unless</span> page-up?
-<span id="L913" class="LineNr"> 913 </span>    render-from:num <span class="Special">&lt;-</span> get *env, <span class="Constant">render-from:offset</span>
-<span id="L914" class="LineNr"> 914 </span>    at-beginning?:bool <span class="Special">&lt;-</span> equal render-from,<span class="Constant"> -1</span>
-<span id="L915" class="LineNr"> 915 </span>    <span class="muControl">break-if</span> at-beginning?
-<span id="L916" class="LineNr"> 916 </span>    render-from <span class="Special">&lt;-</span> subtract render-from,<span class="Constant"> 1</span>
-<span id="L917" class="LineNr"> 917 </span>    *env <span class="Special">&lt;-</span> put *env, <span class="Constant">render-from:offset</span>, render-from
-<span id="L918" class="LineNr"> 918 </span>    <a href='../081print.mu.html#L623'>hide-screen</a> <a href='../081print.mu.html#L4'>screen</a>
-<span id="L919" class="LineNr"> 919 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> render-sandbox-side <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
-<span id="L920" class="LineNr"> 920 </span>    <a href='../081print.mu.html#L631'>show-screen</a> <a href='../081print.mu.html#L4'>screen</a>
-<span id="L921" class="LineNr"> 921 </span>    <span class="muControl">jump</span> <span class="Constant">+finish-event</span>
+<span id="L910" class="LineNr"> 910 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> sandbox-in-focus?
+<span id="L911" class="LineNr"> 911 </span>  <span class="Conceal">¦</span> page-up?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65519/page-up</span>
+<span id="L912" class="LineNr"> 912 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> page-up?
+<span id="L913" class="LineNr"> 913 </span>  <span class="Conceal">¦</span> render-from:num <span class="Special">&lt;-</span> get *env, <span class="Constant">render-from:offset</span>
+<span id="L914" class="LineNr"> 914 </span>  <span class="Conceal">¦</span> at-beginning?:bool <span class="Special">&lt;-</span> equal render-from,<span class="Constant"> -1</span>
+<span id="L915" class="LineNr"> 915 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-beginning?
+<span id="L916" class="LineNr"> 916 </span>  <span class="Conceal">¦</span> render-from <span class="Special">&lt;-</span> subtract render-from,<span class="Constant"> 1</span>
+<span id="L917" class="LineNr"> 917 </span>  <span class="Conceal">¦</span> *env <span class="Special">&lt;-</span> put *env, <span class="Constant">render-from:offset</span>, render-from
+<span id="L918" class="LineNr"> 918 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L623'>hide-screen</a> <a href='../081print.mu.html#L4'>screen</a>
+<span id="L919" class="LineNr"> 919 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> render-sandbox-side <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
+<span id="L920" class="LineNr"> 920 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L631'>show-screen</a> <a href='../081print.mu.html#L4'>screen</a>
+<span id="L921" class="LineNr"> 921 </span>  <span class="Conceal">¦</span> <span class="muControl">jump</span> <span class="Constant">+finish-event</span>
 <span id="L922" class="LineNr"> 922 </span>  <span class="Delimiter">}</span>
 <span id="L923" class="LineNr"> 923 </span>]
 <span id="L924" class="LineNr"> 924 </span>
@@ -992,12 +993,12 @@ if ('onhashchange' in window) {
 <span id="L931" class="LineNr"> 931 </span>  <span class="muControl">return-unless</span> curr, <span class="Constant">0/nil</span>
 <span id="L932" class="LineNr"> 932 </span>  <a href='../065duplex_list.mu.html#L29'>next</a>:&amp;:sandbox <span class="Special">&lt;-</span> get *curr, <span class="Constant">next-sandbox:offset</span>
 <span id="L933" class="LineNr"> 933 </span>  <span class="Delimiter">{</span>
-<span id="L934" class="LineNr"> 934 </span>    <span class="muControl">return-unless</span> <a href='../065duplex_list.mu.html#L29'>next</a>, <span class="Constant">0/nil</span>
-<span id="L935" class="LineNr"> 935 </span>    found?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L29'>next</a>, in
-<span id="L936" class="LineNr"> 936 </span>    <span class="muControl">break-if</span> found?
-<span id="L937" class="LineNr"> 937 </span>    curr <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L29'>next</a>
-<span id="L938" class="LineNr"> 938 </span>    <a href='../065duplex_list.mu.html#L29'>next</a> <span class="Special">&lt;-</span> get *curr, <span class="Constant">next-sandbox:offset</span>
-<span id="L939" class="LineNr"> 939 </span>    <span class="muControl">loop</span>
+<span id="L934" class="LineNr"> 934 </span>  <span class="Conceal">¦</span> <span class="muControl">return-unless</span> <a href='../065duplex_list.mu.html#L29'>next</a>, <span class="Constant">0/nil</span>
+<span id="L935" class="LineNr"> 935 </span>  <span class="Conceal">¦</span> found?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L29'>next</a>, in
+<span id="L936" class="LineNr"> 936 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> found?
+<span id="L937" class="LineNr"> 937 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L29'>next</a>
+<span id="L938" class="LineNr"> 938 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L29'>next</a> <span class="Special">&lt;-</span> get *curr, <span class="Constant">next-sandbox:offset</span>
+<span id="L939" class="LineNr"> 939 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L940" class="LineNr"> 940 </span>  <span class="Delimiter">}</span>
 <span id="L941" class="LineNr"> 941 </span>  <span class="muControl">return</span> curr
 <span id="L942" class="LineNr"> 942 </span>]
@@ -1008,33 +1009,33 @@ if ('onhashchange' in window) {
 <span id="L947" class="LineNr"> 947 </span>  assume-screen <span class="Constant">100/width</span>, <span class="Constant">10/height</span>
 <span id="L948" class="LineNr"> 948 </span>  <span class="Comment"># initialize sandbox side and create a sandbox</span>
 <span id="L949" class="LineNr"> 949 </span>  assume-resources [
-<span id="L950" class="LineNr"> 950 </span>    <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
-<span id="L951" class="LineNr"> 951 </span>      <span class="Constant">||</span>  <span class="Comment"># file containing just a newline</span>
-<span id="L952" class="LineNr"> 952 </span>    ]
+<span id="L950" class="LineNr"> 950 </span>  <span class="Conceal">¦</span> <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
+<span id="L951" class="LineNr"> 951 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Constant">||</span>  <span class="Comment"># file containing just a newline</span>
+<span id="L952" class="LineNr"> 952 </span>  <span class="Conceal">¦</span> ]
 <span id="L953" class="LineNr"> 953 </span>  ]
 <span id="L954" class="LineNr"> 954 </span>  <span class="Comment"># create a sandbox</span>
 <span id="L955" class="LineNr"> 955 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[add 2, 2]</span>
 <span id="L956" class="LineNr"> 956 </span>  <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
 <span id="L957" class="LineNr"> 957 </span>  assume-console [
-<span id="L958" class="LineNr"> 958 </span>    press F4
+<span id="L958" class="LineNr"> 958 </span>  <span class="Conceal">¦</span> press F4
 <span id="L959" class="LineNr"> 959 </span>  ]
 <span id="L960" class="LineNr"> 960 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L961" class="LineNr"> 961 </span>  <span class="Comment"># hit 'down' in recipe editor</span>
 <span id="L962" class="LineNr"> 962 </span>  assume-console [
-<span id="L963" class="LineNr"> 963 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L963" class="LineNr"> 963 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L964" class="LineNr"> 964 </span>  ]
 <span id="L965" class="LineNr"> 965 </span>  run [
-<span id="L966" class="LineNr"> 966 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
-<span id="L967" class="LineNr"> 967 </span>    cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
-<span id="L968" class="LineNr"> 968 </span>    print <a href='../081print.mu.html#L4'>screen</a>, cursor
+<span id="L966" class="LineNr"> 966 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L967" class="LineNr"> 967 </span>  <span class="Conceal">¦</span> cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
+<span id="L968" class="LineNr"> 968 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, cursor
 <span id="L969" class="LineNr"> 969 </span>  ]
 <span id="L970" class="LineNr"> 970 </span>  <span class="Comment"># cursor doesn't move when the end is already on-screen</span>
 <span id="L971" class="LineNr"> 971 </span>  screen-should-contain [
-<span id="L972" class="LineNr"> 972 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L973" class="LineNr"> 973 </span>   <span class="Constant"> .␣                                                 ╎                                                 .</span>
-<span id="L974" class="LineNr"> 974 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L975" class="LineNr"> 975 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎0   edit          copy            delete         .</span>
-<span id="L976" class="LineNr"> 976 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L972" class="LineNr"> 972 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L973" class="LineNr"> 973 </span>  <span class="Conceal">¦</span><span class="Constant"> .␣                                                 ╎                                                 .</span>
+<span id="L974" class="LineNr"> 974 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L975" class="LineNr"> 975 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎0   edit          copy            delete         .</span>
+<span id="L976" class="LineNr"> 976 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
 <span id="L977" class="LineNr"> 977 </span>  ]
 <span id="L978" class="LineNr"> 978 </span>]
 <span id="L979" class="LineNr"> 979 </span>
@@ -1049,145 +1050,145 @@ if ('onhashchange' in window) {
 <span id="L988" class="LineNr"> 988 </span>  <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
 <span id="L989" class="LineNr"> 989 </span>  <span class="Comment"># create 2 sandboxes</span>
 <span id="L990" class="LineNr"> 990 </span>  assume-console [
-<span id="L991" class="LineNr"> 991 </span>    press ctrl-n
-<span id="L992" class="LineNr"> 992 </span>    type <span class="Constant">[add 2, 2]</span>
-<span id="L993" class="LineNr"> 993 </span>    press F4
-<span id="L994" class="LineNr"> 994 </span>    type <span class="Constant">[add 1, 1]</span>
-<span id="L995" class="LineNr"> 995 </span>    press F4
+<span id="L991" class="LineNr"> 991 </span>  <span class="Conceal">¦</span> press ctrl-n
+<span id="L992" class="LineNr"> 992 </span>  <span class="Conceal">¦</span> type <span class="Constant">[add 2, 2]</span>
+<span id="L993" class="LineNr"> 993 </span>  <span class="Conceal">¦</span> press F4
+<span id="L994" class="LineNr"> 994 </span>  <span class="Conceal">¦</span> type <span class="Constant">[add 1, 1]</span>
+<span id="L995" class="LineNr"> 995 </span>  <span class="Conceal">¦</span> press F4
 <span id="L996" class="LineNr"> 996 </span>  ]
 <span id="L997" class="LineNr"> 997 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L998" class="LineNr"> 998 </span>  cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
 <span id="L999" class="LineNr"> 999 </span>  print <a href='../081print.mu.html#L4'>screen</a>, cursor
 <span id="L1000" class="LineNr">1000 </span>  screen-should-contain [
-<span id="L1001" class="LineNr">1001 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L1002" class="LineNr">1002 </span>   <span class="Constant"> .                                                  ╎␣                                                .</span>
-<span id="L1003" class="LineNr">1003 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L1004" class="LineNr">1004 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L1005" class="LineNr">1005 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L1006" class="LineNr">1006 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L1007" class="LineNr">1007 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L1008" class="LineNr">1008 </span>   <span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
-<span id="L1009" class="LineNr">1009 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L1010" class="LineNr">1010 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L1001" class="LineNr">1001 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L1002" class="LineNr">1002 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎␣                                                .</span>
+<span id="L1003" class="LineNr">1003 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L1004" class="LineNr">1004 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L1005" class="LineNr">1005 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L1006" class="LineNr">1006 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L1007" class="LineNr">1007 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L1008" class="LineNr">1008 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
+<span id="L1009" class="LineNr">1009 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L1010" class="LineNr">1010 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
 <span id="L1011" class="LineNr">1011 </span>  ]
 <span id="L1012" class="LineNr">1012 </span>  <span class="Comment"># hit 'page-down'</span>
 <span id="L1013" class="LineNr">1013 </span>  assume-console [
-<span id="L1014" class="LineNr">1014 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L1014" class="LineNr">1014 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L1015" class="LineNr">1015 </span>  ]
 <span id="L1016" class="LineNr">1016 </span>  run [
-<span id="L1017" class="LineNr">1017 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
-<span id="L1018" class="LineNr">1018 </span>    cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
-<span id="L1019" class="LineNr">1019 </span>    print <a href='../081print.mu.html#L4'>screen</a>, cursor
+<span id="L1017" class="LineNr">1017 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L1018" class="LineNr">1018 </span>  <span class="Conceal">¦</span> cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
+<span id="L1019" class="LineNr">1019 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, cursor
 <span id="L1020" class="LineNr">1020 </span>  ]
 <span id="L1021" class="LineNr">1021 </span>  <span class="Comment"># sandbox editor hidden; first sandbox displayed</span>
 <span id="L1022" class="LineNr">1022 </span>  <span class="Comment"># cursor moves to first sandbox</span>
 <span id="L1023" class="LineNr">1023 </span>  screen-should-contain [
-<span id="L1024" class="LineNr">1024 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L1025" class="LineNr">1025 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L1026" class="LineNr">1026 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎␣   edit          copy            delete         .</span>
-<span id="L1027" class="LineNr">1027 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L1028" class="LineNr">1028 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L1029" class="LineNr">1029 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L1030" class="LineNr">1030 </span>   <span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
-<span id="L1031" class="LineNr">1031 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L1032" class="LineNr">1032 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L1024" class="LineNr">1024 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L1025" class="LineNr">1025 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L1026" class="LineNr">1026 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎␣   edit          copy            delete         .</span>
+<span id="L1027" class="LineNr">1027 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L1028" class="LineNr">1028 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L1029" class="LineNr">1029 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L1030" class="LineNr">1030 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
+<span id="L1031" class="LineNr">1031 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L1032" class="LineNr">1032 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
 <span id="L1033" class="LineNr">1033 </span>  ]
 <span id="L1034" class="LineNr">1034 </span>  <span class="Comment"># hit 'page-down' again</span>
 <span id="L1035" class="LineNr">1035 </span>  assume-console [
-<span id="L1036" class="LineNr">1036 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L1036" class="LineNr">1036 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L1037" class="LineNr">1037 </span>  ]
 <span id="L1038" class="LineNr">1038 </span>  run [
-<span id="L1039" class="LineNr">1039 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L1039" class="LineNr">1039 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L1040" class="LineNr">1040 </span>  ]
 <span id="L1041" class="LineNr">1041 </span>  <span class="Comment"># just second sandbox displayed</span>
 <span id="L1042" class="LineNr">1042 </span>  screen-should-contain [
-<span id="L1043" class="LineNr">1043 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L1044" class="LineNr">1044 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L1045" class="LineNr">1045 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎1   edit          copy            delete         .</span>
-<span id="L1046" class="LineNr">1046 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L1047" class="LineNr">1047 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
-<span id="L1048" class="LineNr">1048 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L1049" class="LineNr">1049 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L1043" class="LineNr">1043 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L1044" class="LineNr">1044 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L1045" class="LineNr">1045 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎1   edit          copy            delete         .</span>
+<span id="L1046" class="LineNr">1046 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L1047" class="LineNr">1047 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L1048" class="LineNr">1048 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L1049" class="LineNr">1049 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L1050" class="LineNr">1050 </span>  ]
 <span id="L1051" class="LineNr">1051 </span>  <span class="Comment"># hit 'page-down' again</span>
 <span id="L1052" class="LineNr">1052 </span>  assume-console [
-<span id="L1053" class="LineNr">1053 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L1053" class="LineNr">1053 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L1054" class="LineNr">1054 </span>  ]
 <span id="L1055" class="LineNr">1055 </span>  run [
-<span id="L1056" class="LineNr">1056 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L1056" class="LineNr">1056 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L1057" class="LineNr">1057 </span>  ]
 <span id="L1058" class="LineNr">1058 </span>  <span class="Comment"># no change</span>
 <span id="L1059" class="LineNr">1059 </span>  screen-should-contain [
-<span id="L1060" class="LineNr">1060 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L1061" class="LineNr">1061 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L1062" class="LineNr">1062 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎1   edit          copy            delete         .</span>
-<span id="L1063" class="LineNr">1063 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L1064" class="LineNr">1064 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
-<span id="L1065" class="LineNr">1065 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L1066" class="LineNr">1066 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L1060" class="LineNr">1060 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L1061" class="LineNr">1061 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L1062" class="LineNr">1062 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎1   edit          copy            delete         .</span>
+<span id="L1063" class="LineNr">1063 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L1064" class="LineNr">1064 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L1065" class="LineNr">1065 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L1066" class="LineNr">1066 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L1067" class="LineNr">1067 </span>  ]
 <span id="L1068" class="LineNr">1068 </span>  <span class="Comment"># hit 'page-up'</span>
 <span id="L1069" class="LineNr">1069 </span>  assume-console [
-<span id="L1070" class="LineNr">1070 </span>    press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
+<span id="L1070" class="LineNr">1070 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
 <span id="L1071" class="LineNr">1071 </span>  ]
 <span id="L1072" class="LineNr">1072 </span>  run [
-<span id="L1073" class="LineNr">1073 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L1073" class="LineNr">1073 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L1074" class="LineNr">1074 </span>  ]
 <span id="L1075" class="LineNr">1075 </span>  <span class="Comment"># back to displaying both sandboxes without editor</span>
 <span id="L1076" class="LineNr">1076 </span>  screen-should-contain [
-<span id="L1077" class="LineNr">1077 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L1078" class="LineNr">1078 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L1079" class="LineNr">1079 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎0   edit          copy            delete         .</span>
-<span id="L1080" class="LineNr">1080 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L1081" class="LineNr">1081 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L1082" class="LineNr">1082 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L1083" class="LineNr">1083 </span>   <span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
-<span id="L1084" class="LineNr">1084 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L1085" class="LineNr">1085 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L1077" class="LineNr">1077 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L1078" class="LineNr">1078 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L1079" class="LineNr">1079 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎0   edit          copy            delete         .</span>
+<span id="L1080" class="LineNr">1080 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L1081" class="LineNr">1081 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L1082" class="LineNr">1082 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L1083" class="LineNr">1083 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
+<span id="L1084" class="LineNr">1084 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L1085" class="LineNr">1085 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
 <span id="L1086" class="LineNr">1086 </span>  ]
 <span id="L1087" class="LineNr">1087 </span>  <span class="Comment"># hit 'page-up' again</span>
 <span id="L1088" class="LineNr">1088 </span>  assume-console [
-<span id="L1089" class="LineNr">1089 </span>    press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
+<span id="L1089" class="LineNr">1089 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
 <span id="L1090" class="LineNr">1090 </span>  ]
 <span id="L1091" class="LineNr">1091 </span>  run [
-<span id="L1092" class="LineNr">1092 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
-<span id="L1093" class="LineNr">1093 </span>    cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
-<span id="L1094" class="LineNr">1094 </span>    print <a href='../081print.mu.html#L4'>screen</a>, cursor
+<span id="L1092" class="LineNr">1092 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L1093" class="LineNr">1093 </span>  <span class="Conceal">¦</span> cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
+<span id="L1094" class="LineNr">1094 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, cursor
 <span id="L1095" class="LineNr">1095 </span>  ]
 <span id="L1096" class="LineNr">1096 </span>  <span class="Comment"># back to displaying both sandboxes as well as editor</span>
 <span id="L1097" class="LineNr">1097 </span>  screen-should-contain [
-<span id="L1098" class="LineNr">1098 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L1099" class="LineNr">1099 </span>   <span class="Constant"> .                                                  ╎␣                                                .</span>
-<span id="L1100" class="LineNr">1100 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L1101" class="LineNr">1101 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L1102" class="LineNr">1102 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L1103" class="LineNr">1103 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L1104" class="LineNr">1104 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L1105" class="LineNr">1105 </span>   <span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
-<span id="L1106" class="LineNr">1106 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L1107" class="LineNr">1107 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L1098" class="LineNr">1098 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L1099" class="LineNr">1099 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎␣                                                .</span>
+<span id="L1100" class="LineNr">1100 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L1101" class="LineNr">1101 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L1102" class="LineNr">1102 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L1103" class="LineNr">1103 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L1104" class="LineNr">1104 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L1105" class="LineNr">1105 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
+<span id="L1106" class="LineNr">1106 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L1107" class="LineNr">1107 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
 <span id="L1108" class="LineNr">1108 </span>  ]
 <span id="L1109" class="LineNr">1109 </span>  <span class="Comment"># hit 'page-up' again</span>
 <span id="L1110" class="LineNr">1110 </span>  assume-console [
-<span id="L1111" class="LineNr">1111 </span>    press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
+<span id="L1111" class="LineNr">1111 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
 <span id="L1112" class="LineNr">1112 </span>  ]
 <span id="L1113" class="LineNr">1113 </span>  run [
-<span id="L1114" class="LineNr">1114 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
-<span id="L1115" class="LineNr">1115 </span>    cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
-<span id="L1116" class="LineNr">1116 </span>    print <a href='../081print.mu.html#L4'>screen</a>, cursor
+<span id="L1114" class="LineNr">1114 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L1115" class="LineNr">1115 </span>  <span class="Conceal">¦</span> cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
+<span id="L1116" class="LineNr">1116 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, cursor
 <span id="L1117" class="LineNr">1117 </span>  ]
 <span id="L1118" class="LineNr">1118 </span>  <span class="Comment"># no change</span>
 <span id="L1119" class="LineNr">1119 </span>  screen-should-contain [
-<span id="L1120" class="LineNr">1120 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L1121" class="LineNr">1121 </span>   <span class="Constant"> .                                                  ╎␣                                                .</span>
-<span id="L1122" class="LineNr">1122 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L1123" class="LineNr">1123 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L1124" class="LineNr">1124 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L1125" class="LineNr">1125 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L1126" class="LineNr">1126 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L1127" class="LineNr">1127 </span>   <span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
-<span id="L1128" class="LineNr">1128 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L1129" class="LineNr">1129 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L1120" class="LineNr">1120 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L1121" class="LineNr">1121 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎␣                                                .</span>
+<span id="L1122" class="LineNr">1122 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L1123" class="LineNr">1123 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L1124" class="LineNr">1124 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L1125" class="LineNr">1125 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L1126" class="LineNr">1126 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L1127" class="LineNr">1127 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
+<span id="L1128" class="LineNr">1128 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L1129" class="LineNr">1129 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
 <span id="L1130" class="LineNr">1130 </span>  ]
 <span id="L1131" class="LineNr">1131 </span>]
 <span id="L1132" class="LineNr">1132 </span>
@@ -1202,74 +1203,74 @@ if ('onhashchange' in window) {
 <span id="L1141" class="LineNr">1141 </span>  <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
 <span id="L1142" class="LineNr">1142 </span>  <span class="Comment"># create a sandbox</span>
 <span id="L1143" class="LineNr">1143 </span>  assume-console [
-<span id="L1144" class="LineNr">1144 </span>    press ctrl-n
-<span id="L1145" class="LineNr">1145 </span>    type <span class="Constant">[add 1, 1]</span>
-<span id="L1146" class="LineNr">1146 </span>    press F4
+<span id="L1144" class="LineNr">1144 </span>  <span class="Conceal">¦</span> press ctrl-n
+<span id="L1145" class="LineNr">1145 </span>  <span class="Conceal">¦</span> type <span class="Constant">[add 1, 1]</span>
+<span id="L1146" class="LineNr">1146 </span>  <span class="Conceal">¦</span> press F4
 <span id="L1147" class="LineNr">1147 </span>  ]
 <span id="L1148" class="LineNr">1148 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L1149" class="LineNr">1149 </span>  screen-should-contain [
-<span id="L1150" class="LineNr">1150 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L1151" class="LineNr">1151 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L1152" class="LineNr">1152 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L1153" class="LineNr">1153 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L1154" class="LineNr">1154 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L1155" class="LineNr">1155 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L1156" class="LineNr">1156 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L1157" class="LineNr">1157 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L1150" class="LineNr">1150 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L1151" class="LineNr">1151 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L1152" class="LineNr">1152 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L1153" class="LineNr">1153 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L1154" class="LineNr">1154 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L1155" class="LineNr">1155 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L1156" class="LineNr">1156 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L1157" class="LineNr">1157 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L1158" class="LineNr">1158 </span>  ]
 <span id="L1159" class="LineNr">1159 </span>  <span class="Comment"># hit 'page-down' and 'page-up' a couple of times. sandbox index should be stable</span>
 <span id="L1160" class="LineNr">1160 </span>  assume-console [
-<span id="L1161" class="LineNr">1161 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L1161" class="LineNr">1161 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L1162" class="LineNr">1162 </span>  ]
 <span id="L1163" class="LineNr">1163 </span>  run [
-<span id="L1164" class="LineNr">1164 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L1164" class="LineNr">1164 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L1165" class="LineNr">1165 </span>  ]
 <span id="L1166" class="LineNr">1166 </span>  <span class="Comment"># sandbox editor hidden; first sandbox displayed</span>
 <span id="L1167" class="LineNr">1167 </span>  <span class="Comment"># cursor moves to first sandbox</span>
 <span id="L1168" class="LineNr">1168 </span>  screen-should-contain [
-<span id="L1169" class="LineNr">1169 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L1170" class="LineNr">1170 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L1171" class="LineNr">1171 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎0   edit          copy            delete         .</span>
-<span id="L1172" class="LineNr">1172 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L1173" class="LineNr">1173 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L1174" class="LineNr">1174 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L1175" class="LineNr">1175 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L1169" class="LineNr">1169 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L1170" class="LineNr">1170 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L1171" class="LineNr">1171 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎0   edit          copy            delete         .</span>
+<span id="L1172" class="LineNr">1172 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L1173" class="LineNr">1173 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L1174" class="LineNr">1174 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L1175" class="LineNr">1175 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L1176" class="LineNr">1176 </span>  ]
 <span id="L1177" class="LineNr">1177 </span>  <span class="Comment"># hit 'page-up' again</span>
 <span id="L1178" class="LineNr">1178 </span>  assume-console [
-<span id="L1179" class="LineNr">1179 </span>    press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
+<span id="L1179" class="LineNr">1179 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
 <span id="L1180" class="LineNr">1180 </span>  ]
 <span id="L1181" class="LineNr">1181 </span>  run [
-<span id="L1182" class="LineNr">1182 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L1182" class="LineNr">1182 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L1183" class="LineNr">1183 </span>  ]
 <span id="L1184" class="LineNr">1184 </span>  <span class="Comment"># back to displaying both sandboxes as well as editor</span>
 <span id="L1185" class="LineNr">1185 </span>  screen-should-contain [
-<span id="L1186" class="LineNr">1186 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L1187" class="LineNr">1187 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L1188" class="LineNr">1188 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L1189" class="LineNr">1189 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L1190" class="LineNr">1190 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L1191" class="LineNr">1191 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L1192" class="LineNr">1192 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L1193" class="LineNr">1193 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L1186" class="LineNr">1186 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L1187" class="LineNr">1187 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L1188" class="LineNr">1188 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L1189" class="LineNr">1189 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L1190" class="LineNr">1190 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L1191" class="LineNr">1191 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L1192" class="LineNr">1192 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L1193" class="LineNr">1193 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L1194" class="LineNr">1194 </span>  ]
 <span id="L1195" class="LineNr">1195 </span>  <span class="Comment"># hit 'page-down'</span>
 <span id="L1196" class="LineNr">1196 </span>  assume-console [
-<span id="L1197" class="LineNr">1197 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L1197" class="LineNr">1197 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L1198" class="LineNr">1198 </span>  ]
 <span id="L1199" class="LineNr">1199 </span>  run [
-<span id="L1200" class="LineNr">1200 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L1200" class="LineNr">1200 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L1201" class="LineNr">1201 </span>  ]
 <span id="L1202" class="LineNr">1202 </span>  <span class="Comment"># sandbox editor hidden; first sandbox displayed</span>
 <span id="L1203" class="LineNr">1203 </span>  <span class="Comment"># cursor moves to first sandbox</span>
 <span id="L1204" class="LineNr">1204 </span>  screen-should-contain [
-<span id="L1205" class="LineNr">1205 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L1206" class="LineNr">1206 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L1207" class="LineNr">1207 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎0   edit          copy            delete         .</span>
-<span id="L1208" class="LineNr">1208 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L1209" class="LineNr">1209 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L1210" class="LineNr">1210 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L1211" class="LineNr">1211 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L1205" class="LineNr">1205 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L1206" class="LineNr">1206 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L1207" class="LineNr">1207 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎0   edit          copy            delete         .</span>
+<span id="L1208" class="LineNr">1208 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L1209" class="LineNr">1209 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L1210" class="LineNr">1210 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L1211" class="LineNr">1211 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L1212" class="LineNr">1212 </span>  ]
 <span id="L1213" class="LineNr">1213 </span>]
 </pre>
diff --git a/html/edit/006-sandbox-copy.mu.html b/html/edit/006-sandbox-copy.mu.html
index b5c5bb85..3ece6b06 100644
--- a/html/edit/006-sandbox-copy.mu.html
+++ b/html/edit/006-sandbox-copy.mu.html
@@ -15,15 +15,16 @@ body { font-size: 12pt; font-family: monospace; color: #eeeeee; background-color
 a { text-decoration: none; }
 a:hover { text-decoration: underline; }
 * { font-size: 12pt; font-size: 1em; }
-.Delimiter { color: #800080; }
-.muControl { color: #c0a020; }
+.Conceal { color: #4e4e4e; }
+.muScenario { color: #00af00; }
 .Special { color: #c00000; }
+.Delimiter { color: #800080; }
 .SalientComment { color: #00ffff; }
 .Constant { color: #00a0a0; }
 .LineNr { color: #444444; }
-.Comment { color: #9090ff; }
 .muRecipe { color: #ff8700; }
-.muScenario { color: #00af00; }
+.Comment { color: #9090ff; }
+.muControl { color: #c0a020; }
 -->
 </style>
 
@@ -71,53 +72,53 @@ if ('onhashchange' in window) {
 <span id="L11" class="LineNr"> 11 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[add 1, 1]</span>  <span class="Comment"># contents of sandbox editor</span>
 <span id="L12" class="LineNr"> 12 </span>  <span class="Comment"># run it</span>
 <span id="L13" class="LineNr"> 13 </span>  assume-console [
-<span id="L14" class="LineNr"> 14 </span>    press F4
+<span id="L14" class="LineNr"> 14 </span>  <span class="Conceal">¦</span> press F4
 <span id="L15" class="LineNr"> 15 </span>  ]
 <span id="L16" class="LineNr"> 16 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L17" class="LineNr"> 17 </span>  screen-should-contain [
-<span id="L18" class="LineNr"> 18 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L19" class="LineNr"> 19 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L20" class="LineNr"> 20 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L21" class="LineNr"> 21 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L22" class="LineNr"> 22 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L23" class="LineNr"> 23 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L24" class="LineNr"> 24 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L25" class="LineNr"> 25 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L18" class="LineNr"> 18 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L19" class="LineNr"> 19 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L20" class="LineNr"> 20 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L21" class="LineNr"> 21 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L22" class="LineNr"> 22 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L23" class="LineNr"> 23 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L24" class="LineNr"> 24 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L25" class="LineNr"> 25 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L26" class="LineNr"> 26 </span>  ]
 <span id="L27" class="LineNr"> 27 </span>  <span class="Comment"># click at left edge of 'copy' button</span>
 <span id="L28" class="LineNr"> 28 </span>  assume-console [
-<span id="L29" class="LineNr"> 29 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 69</span>
+<span id="L29" class="LineNr"> 29 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 69</span>
 <span id="L30" class="LineNr"> 30 </span>  ]
 <span id="L31" class="LineNr"> 31 </span>  run [
-<span id="L32" class="LineNr"> 32 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L32" class="LineNr"> 32 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L33" class="LineNr"> 33 </span>  ]
 <span id="L34" class="LineNr"> 34 </span>  <span class="Comment"># it copies into editor</span>
 <span id="L35" class="LineNr"> 35 </span>  screen-should-contain [
-<span id="L36" class="LineNr"> 36 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L37" class="LineNr"> 37 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L38" class="LineNr"> 38 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L39" class="LineNr"> 39 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L40" class="LineNr"> 40 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L41" class="LineNr"> 41 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L42" class="LineNr"> 42 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L43" class="LineNr"> 43 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L36" class="LineNr"> 36 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L37" class="LineNr"> 37 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L38" class="LineNr"> 38 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L39" class="LineNr"> 39 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L40" class="LineNr"> 40 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L41" class="LineNr"> 41 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L42" class="LineNr"> 42 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L43" class="LineNr"> 43 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L44" class="LineNr"> 44 </span>  ]
 <span id="L45" class="LineNr"> 45 </span>  <span class="Comment"># cursor should be in the right place</span>
 <span id="L46" class="LineNr"> 46 </span>  assume-console [
-<span id="L47" class="LineNr"> 47 </span>    type <span class="Constant">[0]</span>
+<span id="L47" class="LineNr"> 47 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
 <span id="L48" class="LineNr"> 48 </span>  ]
 <span id="L49" class="LineNr"> 49 </span>  run [
-<span id="L50" class="LineNr"> 50 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L50" class="LineNr"> 50 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L51" class="LineNr"> 51 </span>  ]
 <span id="L52" class="LineNr"> 52 </span>  screen-should-contain [
-<span id="L53" class="LineNr"> 53 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L54" class="LineNr"> 54 </span>   <span class="Constant"> .                                                  ╎0add 1, 1                                        .</span>
-<span id="L55" class="LineNr"> 55 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L56" class="LineNr"> 56 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L57" class="LineNr"> 57 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L58" class="LineNr"> 58 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L59" class="LineNr"> 59 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L60" class="LineNr"> 60 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L53" class="LineNr"> 53 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L54" class="LineNr"> 54 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0add 1, 1                                        .</span>
+<span id="L55" class="LineNr"> 55 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L56" class="LineNr"> 56 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L57" class="LineNr"> 57 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L58" class="LineNr"> 58 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L59" class="LineNr"> 59 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L60" class="LineNr"> 60 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L61" class="LineNr"> 61 </span>  ]
 <span id="L62" class="LineNr"> 62 </span>]
 <span id="L63" class="LineNr"> 63 </span>
@@ -131,68 +132,68 @@ if ('onhashchange' in window) {
 <span id="L71" class="LineNr"> 71 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[add 1, 1]</span>  <span class="Comment"># contents of sandbox editor</span>
 <span id="L72" class="LineNr"> 72 </span>  <span class="Comment"># run it</span>
 <span id="L73" class="LineNr"> 73 </span>  assume-console [
-<span id="L74" class="LineNr"> 74 </span>    press F4
+<span id="L74" class="LineNr"> 74 </span>  <span class="Conceal">¦</span> press F4
 <span id="L75" class="LineNr"> 75 </span>  ]
 <span id="L76" class="LineNr"> 76 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L77" class="LineNr"> 77 </span>  screen-should-contain [
-<span id="L78" class="LineNr"> 78 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L79" class="LineNr"> 79 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L80" class="LineNr"> 80 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L81" class="LineNr"> 81 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L82" class="LineNr"> 82 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L83" class="LineNr"> 83 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L84" class="LineNr"> 84 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L85" class="LineNr"> 85 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L78" class="LineNr"> 78 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L79" class="LineNr"> 79 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L80" class="LineNr"> 80 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L81" class="LineNr"> 81 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L82" class="LineNr"> 82 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L83" class="LineNr"> 83 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L84" class="LineNr"> 84 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L85" class="LineNr"> 85 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L86" class="LineNr"> 86 </span>  ]
 <span id="L87" class="LineNr"> 87 </span>  <span class="Comment"># click at right edge of 'copy' button (just before 'delete')</span>
 <span id="L88" class="LineNr"> 88 </span>  assume-console [
-<span id="L89" class="LineNr"> 89 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 84</span>
+<span id="L89" class="LineNr"> 89 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 84</span>
 <span id="L90" class="LineNr"> 90 </span>  ]
 <span id="L91" class="LineNr"> 91 </span>  run [
-<span id="L92" class="LineNr"> 92 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L92" class="LineNr"> 92 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L93" class="LineNr"> 93 </span>  ]
 <span id="L94" class="LineNr"> 94 </span>  <span class="Comment"># it copies into editor</span>
 <span id="L95" class="LineNr"> 95 </span>  screen-should-contain [
-<span id="L96" class="LineNr"> 96 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L97" class="LineNr"> 97 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L98" class="LineNr"> 98 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L99" class="LineNr"> 99 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L100" class="LineNr">100 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L101" class="LineNr">101 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L102" class="LineNr">102 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L103" class="LineNr">103 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L96" class="LineNr"> 96 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L97" class="LineNr"> 97 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L98" class="LineNr"> 98 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L99" class="LineNr"> 99 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L100" class="LineNr">100 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L101" class="LineNr">101 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L102" class="LineNr">102 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L103" class="LineNr">103 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L104" class="LineNr">104 </span>  ]
 <span id="L105" class="LineNr">105 </span>  <span class="Comment"># cursor should be in the right place</span>
 <span id="L106" class="LineNr">106 </span>  assume-console [
-<span id="L107" class="LineNr">107 </span>    type <span class="Constant">[0]</span>
+<span id="L107" class="LineNr">107 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
 <span id="L108" class="LineNr">108 </span>  ]
 <span id="L109" class="LineNr">109 </span>  run [
-<span id="L110" class="LineNr">110 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L110" class="LineNr">110 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L111" class="LineNr">111 </span>  ]
 <span id="L112" class="LineNr">112 </span>  screen-should-contain [
-<span id="L113" class="LineNr">113 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L114" class="LineNr">114 </span>   <span class="Constant"> .                                                  ╎0add 1, 1                                        .</span>
-<span id="L115" class="LineNr">115 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L116" class="LineNr">116 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L117" class="LineNr">117 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L118" class="LineNr">118 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L119" class="LineNr">119 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L120" class="LineNr">120 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L113" class="LineNr">113 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L114" class="LineNr">114 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0add 1, 1                                        .</span>
+<span id="L115" class="LineNr">115 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L116" class="LineNr">116 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L117" class="LineNr">117 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L118" class="LineNr">118 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L119" class="LineNr">119 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L120" class="LineNr">120 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L121" class="LineNr">121 </span>  ]
 <span id="L122" class="LineNr">122 </span>]
 <span id="L123" class="LineNr">123 </span>
 <span id="L124" class="LineNr">124 </span><span class="muRecipe">after</span> <span class="Constant"><a href='004-programming-environment.mu.html#L80'>&lt;global-touch&gt;</a></span> [
 <span id="L125" class="LineNr">125 </span>  <span class="Comment"># support 'copy' button</span>
 <span id="L126" class="LineNr">126 </span>  <span class="Delimiter">{</span>
-<span id="L127" class="LineNr">127 </span>    copy?:bool <span class="Special">&lt;-</span> <a href='006-sandbox-copy.mu.html#L140'>should-attempt-copy?</a> click-row, click-column, env
-<span id="L128" class="LineNr">128 </span>    <span class="muControl">break-unless</span> copy?
-<span id="L129" class="LineNr">129 </span>    copy?, env <span class="Special">&lt;-</span> <a href='006-sandbox-copy.mu.html#L159'>try-copy-sandbox</a> click-row, env
-<span id="L130" class="LineNr">130 </span>    <span class="muControl">break-unless</span> copy?
-<span id="L131" class="LineNr">131 </span>    <a href='../081print.mu.html#L623'>hide-screen</a> <a href='../081print.mu.html#L4'>screen</a>
-<span id="L132" class="LineNr">132 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> render-sandbox-side <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
-<span id="L133" class="LineNr">133 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L511'>update-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, recipes, current-sandbox, sandbox-in-focus?, env
-<span id="L134" class="LineNr">134 </span>    <a href='../081print.mu.html#L631'>show-screen</a> <a href='../081print.mu.html#L4'>screen</a>
-<span id="L135" class="LineNr">135 </span>    <span class="muControl">loop</span> <span class="Constant">+next-event</span>
+<span id="L127" class="LineNr">127 </span>  <span class="Conceal">¦</span> copy?:bool <span class="Special">&lt;-</span> <a href='006-sandbox-copy.mu.html#L140'>should-attempt-copy?</a> click-row, click-column, env
+<span id="L128" class="LineNr">128 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> copy?
+<span id="L129" class="LineNr">129 </span>  <span class="Conceal">¦</span> copy?, env <span class="Special">&lt;-</span> <a href='006-sandbox-copy.mu.html#L159'>try-copy-sandbox</a> click-row, env
+<span id="L130" class="LineNr">130 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> copy?
+<span id="L131" class="LineNr">131 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L623'>hide-screen</a> <a href='../081print.mu.html#L4'>screen</a>
+<span id="L132" class="LineNr">132 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> render-sandbox-side <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
+<span id="L133" class="LineNr">133 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L511'>update-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, recipes, current-sandbox, sandbox-in-focus?, env
+<span id="L134" class="LineNr">134 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L631'>show-screen</a> <a href='../081print.mu.html#L4'>screen</a>
+<span id="L135" class="LineNr">135 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-event</span>
 <span id="L136" class="LineNr">136 </span>  <span class="Delimiter">}</span>
 <span id="L137" class="LineNr">137 </span>]
 <span id="L138" class="LineNr">138 </span>
@@ -237,12 +238,12 @@ if ('onhashchange' in window) {
 <span id="L177" class="LineNr">177 </span>  <span class="Constant">load-ingredients</span>
 <span id="L178" class="LineNr">178 </span>  curr-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *env, <span class="Constant">sandbox:offset</span>
 <span id="L179" class="LineNr">179 </span>  <span class="Delimiter">{</span>
-<span id="L180" class="LineNr">180 </span>    <span class="muControl">break-unless</span> curr-sandbox
-<span id="L181" class="LineNr">181 </span>    start:num <span class="Special">&lt;-</span> get *curr-sandbox, <span class="Constant">starting-row-on-screen:offset</span>
-<span id="L182" class="LineNr">182 </span>    found?:bool <span class="Special">&lt;-</span> equal click-row, start
-<span id="L183" class="LineNr">183 </span>    <span class="muControl">return-if</span> found?, curr-sandbox
-<span id="L184" class="LineNr">184 </span>    curr-sandbox <span class="Special">&lt;-</span> get *curr-sandbox, <span class="Constant">next-sandbox:offset</span>
-<span id="L185" class="LineNr">185 </span>    <span class="muControl">loop</span>
+<span id="L180" class="LineNr">180 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> curr-sandbox
+<span id="L181" class="LineNr">181 </span>  <span class="Conceal">¦</span> start:num <span class="Special">&lt;-</span> get *curr-sandbox, <span class="Constant">starting-row-on-screen:offset</span>
+<span id="L182" class="LineNr">182 </span>  <span class="Conceal">¦</span> found?:bool <span class="Special">&lt;-</span> equal click-row, start
+<span id="L183" class="LineNr">183 </span>  <span class="Conceal">¦</span> <span class="muControl">return-if</span> found?, curr-sandbox
+<span id="L184" class="LineNr">184 </span>  <span class="Conceal">¦</span> curr-sandbox <span class="Special">&lt;-</span> get *curr-sandbox, <span class="Constant">next-sandbox:offset</span>
+<span id="L185" class="LineNr">185 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L186" class="LineNr">186 </span>  <span class="Delimiter">}</span>
 <span id="L187" class="LineNr">187 </span>  <span class="muControl">return</span> <span class="Constant">0/not-found</span>
 <span id="L188" class="LineNr">188 </span>]
@@ -286,55 +287,55 @@ if ('onhashchange' in window) {
 <span id="L226" class="LineNr">226 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[add 1, 1]</span>  <span class="Comment"># contents of sandbox editor</span>
 <span id="L227" class="LineNr">227 </span>  <span class="Comment"># run it</span>
 <span id="L228" class="LineNr">228 </span>  assume-console [
-<span id="L229" class="LineNr">229 </span>    press F4
+<span id="L229" class="LineNr">229 </span>  <span class="Conceal">¦</span> press F4
 <span id="L230" class="LineNr">230 </span>  ]
 <span id="L231" class="LineNr">231 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L232" class="LineNr">232 </span>  screen-should-contain [
-<span id="L233" class="LineNr">233 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L234" class="LineNr">234 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L235" class="LineNr">235 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L236" class="LineNr">236 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L237" class="LineNr">237 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L238" class="LineNr">238 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L239" class="LineNr">239 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L240" class="LineNr">240 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L233" class="LineNr">233 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L234" class="LineNr">234 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L235" class="LineNr">235 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L236" class="LineNr">236 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L237" class="LineNr">237 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L238" class="LineNr">238 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L239" class="LineNr">239 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L240" class="LineNr">240 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L241" class="LineNr">241 </span>  ]
 <span id="L242" class="LineNr">242 </span>  <span class="Comment"># type something into the sandbox editor, then click on the 'copy' button</span>
 <span id="L243" class="LineNr">243 </span>  assume-console [
-<span id="L244" class="LineNr">244 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 70</span>  <span class="Comment"># put cursor in sandbox editor</span>
-<span id="L245" class="LineNr">245 </span>    type <span class="Constant">[0]</span>  <span class="Comment"># type something</span>
-<span id="L246" class="LineNr">246 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 70</span>  <span class="Comment"># click 'copy' button</span>
+<span id="L244" class="LineNr">244 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 70</span>  <span class="Comment"># put cursor in sandbox editor</span>
+<span id="L245" class="LineNr">245 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>  <span class="Comment"># type something</span>
+<span id="L246" class="LineNr">246 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 70</span>  <span class="Comment"># click 'copy' button</span>
 <span id="L247" class="LineNr">247 </span>  ]
 <span id="L248" class="LineNr">248 </span>  run [
-<span id="L249" class="LineNr">249 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L249" class="LineNr">249 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L250" class="LineNr">250 </span>  ]
 <span id="L251" class="LineNr">251 </span>  <span class="Comment"># copy doesn't happen</span>
 <span id="L252" class="LineNr">252 </span>  screen-should-contain [
-<span id="L253" class="LineNr">253 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L254" class="LineNr">254 </span>   <span class="Constant"> .                                                  ╎0                                                .</span>
-<span id="L255" class="LineNr">255 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L256" class="LineNr">256 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L257" class="LineNr">257 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L258" class="LineNr">258 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L259" class="LineNr">259 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L260" class="LineNr">260 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L253" class="LineNr">253 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L254" class="LineNr">254 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0                                                .</span>
+<span id="L255" class="LineNr">255 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L256" class="LineNr">256 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L257" class="LineNr">257 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L258" class="LineNr">258 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L259" class="LineNr">259 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L260" class="LineNr">260 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L261" class="LineNr">261 </span>  ]
 <span id="L262" class="LineNr">262 </span>  <span class="Comment"># cursor should be in the right place</span>
 <span id="L263" class="LineNr">263 </span>  assume-console [
-<span id="L264" class="LineNr">264 </span>    type <span class="Constant">[1]</span>
+<span id="L264" class="LineNr">264 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
 <span id="L265" class="LineNr">265 </span>  ]
 <span id="L266" class="LineNr">266 </span>  run [
-<span id="L267" class="LineNr">267 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L267" class="LineNr">267 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L268" class="LineNr">268 </span>  ]
 <span id="L269" class="LineNr">269 </span>  screen-should-contain [
-<span id="L270" class="LineNr">270 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L271" class="LineNr">271 </span>   <span class="Constant"> .                                                  ╎01                                               .</span>
-<span id="L272" class="LineNr">272 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L273" class="LineNr">273 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L274" class="LineNr">274 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L275" class="LineNr">275 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L276" class="LineNr">276 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L277" class="LineNr">277 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L270" class="LineNr">270 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L271" class="LineNr">271 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎01                                               .</span>
+<span id="L272" class="LineNr">272 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L273" class="LineNr">273 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L274" class="LineNr">274 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L275" class="LineNr">275 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L276" class="LineNr">276 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L277" class="LineNr">277 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L278" class="LineNr">278 </span>  ]
 <span id="L279" class="LineNr">279 </span>]
 </pre>
diff --git a/html/edit/007-sandbox-delete.mu.html b/html/edit/007-sandbox-delete.mu.html
index f8292598..f9371d93 100644
--- a/html/edit/007-sandbox-delete.mu.html
+++ b/html/edit/007-sandbox-delete.mu.html
@@ -15,15 +15,16 @@ body { font-size: 12pt; font-family: monospace; color: #eeeeee; background-color
 a { text-decoration: none; }
 a:hover { text-decoration: underline; }
 * { font-size: 12pt; font-size: 1em; }
-.Delimiter { color: #800080; }
-.muControl { color: #c0a020; }
+.Conceal { color: #4e4e4e; }
+.muScenario { color: #00af00; }
 .Special { color: #c00000; }
+.Delimiter { color: #800080; }
 .SalientComment { color: #00ffff; }
 .Constant { color: #00a0a0; }
 .LineNr { color: #444444; }
-.Comment { color: #9090ff; }
 .muRecipe { color: #ff8700; }
-.muScenario { color: #00af00; }
+.Comment { color: #9090ff; }
+.muControl { color: #c0a020; }
 -->
 </style>
 
@@ -69,74 +70,74 @@ if ('onhashchange' in window) {
 <span id="L9" class="LineNr">  9 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[]</span>
 <span id="L10" class="LineNr"> 10 </span>  <span class="Comment"># run a few commands</span>
 <span id="L11" class="LineNr"> 11 </span>  assume-console [
-<span id="L12" class="LineNr"> 12 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 80</span>
-<span id="L13" class="LineNr"> 13 </span>    type <span class="Constant">[divide-with-remainder 11, 3]</span>
-<span id="L14" class="LineNr"> 14 </span>    press F4
-<span id="L15" class="LineNr"> 15 </span>    type <span class="Constant">[add 2, 2]</span>
-<span id="L16" class="LineNr"> 16 </span>    press F4
+<span id="L12" class="LineNr"> 12 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 80</span>
+<span id="L13" class="LineNr"> 13 </span>  <span class="Conceal">¦</span> type <span class="Constant">[divide-with-remainder 11, 3]</span>
+<span id="L14" class="LineNr"> 14 </span>  <span class="Conceal">¦</span> press F4
+<span id="L15" class="LineNr"> 15 </span>  <span class="Conceal">¦</span> type <span class="Constant">[add 2, 2]</span>
+<span id="L16" class="LineNr"> 16 </span>  <span class="Conceal">¦</span> press F4
 <span id="L17" class="LineNr"> 17 </span>  ]
 <span id="L18" class="LineNr"> 18 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L19" class="LineNr"> 19 </span>  screen-should-contain [
-<span id="L20" class="LineNr"> 20 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L21" class="LineNr"> 21 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L22" class="LineNr"> 22 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L23" class="LineNr"> 23 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L24" class="LineNr"> 24 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L25" class="LineNr"> 25 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
-<span id="L26" class="LineNr"> 26 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L27" class="LineNr"> 27 </span>   <span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
-<span id="L28" class="LineNr"> 28 </span>   <span class="Constant"> .                                                  ╎divide-with-remainder 11, 3                      .</span>
-<span id="L29" class="LineNr"> 29 </span>   <span class="Constant"> .                                                  ╎3                                                .</span>
-<span id="L30" class="LineNr"> 30 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L31" class="LineNr"> 31 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L32" class="LineNr"> 32 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L20" class="LineNr"> 20 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L21" class="LineNr"> 21 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L22" class="LineNr"> 22 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L23" class="LineNr"> 23 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L24" class="LineNr"> 24 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L25" class="LineNr"> 25 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L26" class="LineNr"> 26 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L27" class="LineNr"> 27 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
+<span id="L28" class="LineNr"> 28 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎divide-with-remainder 11, 3                      .</span>
+<span id="L29" class="LineNr"> 29 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎3                                                .</span>
+<span id="L30" class="LineNr"> 30 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L31" class="LineNr"> 31 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L32" class="LineNr"> 32 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L33" class="LineNr"> 33 </span>  ]
 <span id="L34" class="LineNr"> 34 </span>  <span class="Comment"># delete second sandbox by clicking on left edge of 'delete' button</span>
 <span id="L35" class="LineNr"> 35 </span>  assume-console [
-<span id="L36" class="LineNr"> 36 </span>    left-click<span class="Constant"> 7</span>,<span class="Constant"> 85</span>
+<span id="L36" class="LineNr"> 36 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 7</span>,<span class="Constant"> 85</span>
 <span id="L37" class="LineNr"> 37 </span>  ]
 <span id="L38" class="LineNr"> 38 </span>  run [
-<span id="L39" class="LineNr"> 39 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L39" class="LineNr"> 39 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L40" class="LineNr"> 40 </span>  ]
 <span id="L41" class="LineNr"> 41 </span>  screen-should-contain [
-<span id="L42" class="LineNr"> 42 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L43" class="LineNr"> 43 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L44" class="LineNr"> 44 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L45" class="LineNr"> 45 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L46" class="LineNr"> 46 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L47" class="LineNr"> 47 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
-<span id="L48" class="LineNr"> 48 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L49" class="LineNr"> 49 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L50" class="LineNr"> 50 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L42" class="LineNr"> 42 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L43" class="LineNr"> 43 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L44" class="LineNr"> 44 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L45" class="LineNr"> 45 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L46" class="LineNr"> 46 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L47" class="LineNr"> 47 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L48" class="LineNr"> 48 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L49" class="LineNr"> 49 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L50" class="LineNr"> 50 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L51" class="LineNr"> 51 </span>  ]
 <span id="L52" class="LineNr"> 52 </span>  <span class="Comment"># delete first sandbox by clicking at right edge of 'delete' button</span>
 <span id="L53" class="LineNr"> 53 </span>  assume-console [
-<span id="L54" class="LineNr"> 54 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 99</span>
+<span id="L54" class="LineNr"> 54 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 99</span>
 <span id="L55" class="LineNr"> 55 </span>  ]
 <span id="L56" class="LineNr"> 56 </span>  run [
-<span id="L57" class="LineNr"> 57 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L57" class="LineNr"> 57 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L58" class="LineNr"> 58 </span>  ]
 <span id="L59" class="LineNr"> 59 </span>  screen-should-contain [
-<span id="L60" class="LineNr"> 60 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L61" class="LineNr"> 61 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L62" class="LineNr"> 62 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L63" class="LineNr"> 63 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L64" class="LineNr"> 64 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L60" class="LineNr"> 60 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L61" class="LineNr"> 61 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L62" class="LineNr"> 62 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L63" class="LineNr"> 63 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L64" class="LineNr"> 64 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L65" class="LineNr"> 65 </span>  ]
 <span id="L66" class="LineNr"> 66 </span>]
 <span id="L67" class="LineNr"> 67 </span>
 <span id="L68" class="LineNr"> 68 </span><span class="muRecipe">after</span> <span class="Constant"><a href='004-programming-environment.mu.html#L80'>&lt;global-touch&gt;</a></span> [
 <span id="L69" class="LineNr"> 69 </span>  <span class="Comment"># support 'delete' button</span>
 <span id="L70" class="LineNr"> 70 </span>  <span class="Delimiter">{</span>
-<span id="L71" class="LineNr"> 71 </span>    delete?:bool <span class="Special">&lt;-</span> <a href='007-sandbox-delete.mu.html#L84'>should-attempt-delete?</a> click-row, click-column, env
-<span id="L72" class="LineNr"> 72 </span>    <span class="muControl">break-unless</span> delete?
-<span id="L73" class="LineNr"> 73 </span>    delete?, env <span class="Special">&lt;-</span> <a href='007-sandbox-delete.mu.html#L99'>try-delete-sandbox</a> click-row, env
-<span id="L74" class="LineNr"> 74 </span>    <span class="muControl">break-unless</span> delete?
-<span id="L75" class="LineNr"> 75 </span>    <a href='../081print.mu.html#L623'>hide-screen</a> <a href='../081print.mu.html#L4'>screen</a>
-<span id="L76" class="LineNr"> 76 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> render-sandbox-side <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
-<span id="L77" class="LineNr"> 77 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L511'>update-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, recipes, current-sandbox, sandbox-in-focus?, env
-<span id="L78" class="LineNr"> 78 </span>    <a href='../081print.mu.html#L631'>show-screen</a> <a href='../081print.mu.html#L4'>screen</a>
-<span id="L79" class="LineNr"> 79 </span>    <span class="muControl">loop</span> <span class="Constant">+next-event</span>
+<span id="L71" class="LineNr"> 71 </span>  <span class="Conceal">¦</span> delete?:bool <span class="Special">&lt;-</span> <a href='007-sandbox-delete.mu.html#L84'>should-attempt-delete?</a> click-row, click-column, env
+<span id="L72" class="LineNr"> 72 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> delete?
+<span id="L73" class="LineNr"> 73 </span>  <span class="Conceal">¦</span> delete?, env <span class="Special">&lt;-</span> <a href='007-sandbox-delete.mu.html#L99'>try-delete-sandbox</a> click-row, env
+<span id="L74" class="LineNr"> 74 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> delete?
+<span id="L75" class="LineNr"> 75 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L623'>hide-screen</a> <a href='../081print.mu.html#L4'>screen</a>
+<span id="L76" class="LineNr"> 76 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> render-sandbox-side <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
+<span id="L77" class="LineNr"> 77 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L511'>update-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, recipes, current-sandbox, sandbox-in-focus?, env
+<span id="L78" class="LineNr"> 78 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L631'>show-screen</a> <a href='../081print.mu.html#L4'>screen</a>
+<span id="L79" class="LineNr"> 79 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-event</span>
 <span id="L80" class="LineNr"> 80 </span>  <span class="Delimiter">}</span>
 <span id="L81" class="LineNr"> 81 </span>]
 <span id="L82" class="LineNr"> 82 </span>
@@ -172,27 +173,27 @@ if ('onhashchange' in window) {
 <span id="L112" class="LineNr">112 </span>  curr-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *env, <span class="Constant">sandbox:offset</span>
 <span id="L113" class="LineNr">113 </span>  first-sandbox?:bool <span class="Special">&lt;-</span> equal curr-sandbox, sandbox
 <span id="L114" class="LineNr">114 </span>  <span class="Delimiter">{</span>
-<span id="L115" class="LineNr">115 </span>    <span class="Comment"># first sandbox? pop</span>
-<span id="L116" class="LineNr">116 </span>    <span class="muControl">break-unless</span> first-sandbox?
-<span id="L117" class="LineNr">117 </span>    next-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *curr-sandbox, <span class="Constant">next-sandbox:offset</span>
-<span id="L118" class="LineNr">118 </span>    *env <span class="Special">&lt;-</span> put *env, <span class="Constant">sandbox:offset</span>, next-sandbox
+<span id="L115" class="LineNr">115 </span>  <span class="Conceal">¦</span> <span class="Comment"># first sandbox? pop</span>
+<span id="L116" class="LineNr">116 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> first-sandbox?
+<span id="L117" class="LineNr">117 </span>  <span class="Conceal">¦</span> next-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *curr-sandbox, <span class="Constant">next-sandbox:offset</span>
+<span id="L118" class="LineNr">118 </span>  <span class="Conceal">¦</span> *env <span class="Special">&lt;-</span> put *env, <span class="Constant">sandbox:offset</span>, next-sandbox
 <span id="L119" class="LineNr">119 </span>  <span class="Delimiter">}</span>
 <span id="L120" class="LineNr">120 </span>  <span class="Delimiter">{</span>
-<span id="L121" class="LineNr">121 </span>    <span class="Comment"># not first sandbox?</span>
-<span id="L122" class="LineNr">122 </span>    <span class="muControl">break-if</span> first-sandbox?
-<span id="L123" class="LineNr">123 </span>    prev-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> copy curr-sandbox
-<span id="L124" class="LineNr">124 </span>    curr-sandbox <span class="Special">&lt;-</span> get *curr-sandbox, <span class="Constant">next-sandbox:offset</span>
-<span id="L125" class="LineNr">125 </span>    <span class="Delimiter">{</span>
-<span id="L126" class="LineNr">126 </span>      assert curr-sandbox, <span class="Constant">[sandbox not found! something is wrong.]</span>
-<span id="L127" class="LineNr">127 </span>      found?:bool <span class="Special">&lt;-</span> equal curr-sandbox, sandbox
-<span id="L128" class="LineNr">128 </span>      <span class="muControl">break-if</span> found?
-<span id="L129" class="LineNr">129 </span>      prev-sandbox <span class="Special">&lt;-</span> copy curr-sandbox
-<span id="L130" class="LineNr">130 </span>      curr-sandbox <span class="Special">&lt;-</span> get *curr-sandbox, <span class="Constant">next-sandbox:offset</span>
-<span id="L131" class="LineNr">131 </span>      <span class="muControl">loop</span>
-<span id="L132" class="LineNr">132 </span>    <span class="Delimiter">}</span>
-<span id="L133" class="LineNr">133 </span>    <span class="Comment"># snip sandbox out of its list</span>
-<span id="L134" class="LineNr">134 </span>    next-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *curr-sandbox, <span class="Constant">next-sandbox:offset</span>
-<span id="L135" class="LineNr">135 </span>    *prev-sandbox <span class="Special">&lt;-</span> put *prev-sandbox, <span class="Constant">next-sandbox:offset</span>, next-sandbox
+<span id="L121" class="LineNr">121 </span>  <span class="Conceal">¦</span> <span class="Comment"># not first sandbox?</span>
+<span id="L122" class="LineNr">122 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> first-sandbox?
+<span id="L123" class="LineNr">123 </span>  <span class="Conceal">¦</span> prev-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> copy curr-sandbox
+<span id="L124" class="LineNr">124 </span>  <span class="Conceal">¦</span> curr-sandbox <span class="Special">&lt;-</span> get *curr-sandbox, <span class="Constant">next-sandbox:offset</span>
+<span id="L125" class="LineNr">125 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L126" class="LineNr">126 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> assert curr-sandbox, <span class="Constant">[sandbox not found! something is wrong.]</span>
+<span id="L127" class="LineNr">127 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> found?:bool <span class="Special">&lt;-</span> equal curr-sandbox, sandbox
+<span id="L128" class="LineNr">128 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> found?
+<span id="L129" class="LineNr">129 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> prev-sandbox <span class="Special">&lt;-</span> copy curr-sandbox
+<span id="L130" class="LineNr">130 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr-sandbox <span class="Special">&lt;-</span> get *curr-sandbox, <span class="Constant">next-sandbox:offset</span>
+<span id="L131" class="LineNr">131 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span>
+<span id="L132" class="LineNr">132 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L133" class="LineNr">133 </span>  <span class="Conceal">¦</span> <span class="Comment"># snip sandbox out of its list</span>
+<span id="L134" class="LineNr">134 </span>  <span class="Conceal">¦</span> next-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *curr-sandbox, <span class="Constant">next-sandbox:offset</span>
+<span id="L135" class="LineNr">135 </span>  <span class="Conceal">¦</span> *prev-sandbox <span class="Special">&lt;-</span> put *prev-sandbox, <span class="Constant">next-sandbox:offset</span>, next-sandbox
 <span id="L136" class="LineNr">136 </span>  <span class="Delimiter">}</span>
 <span id="L137" class="LineNr">137 </span>  <span class="Comment"># update sandbox count</span>
 <span id="L138" class="LineNr">138 </span>  sandbox-count:num <span class="Special">&lt;-</span> get *env, <span class="Constant">number-of-sandboxes:offset</span>
@@ -200,11 +201,11 @@ if ('onhashchange' in window) {
 <span id="L140" class="LineNr">140 </span>  *env <span class="Special">&lt;-</span> put *env, <span class="Constant">number-of-sandboxes:offset</span>, sandbox-count
 <span id="L141" class="LineNr">141 </span>  <span class="Comment"># reset scroll if deleted sandbox was last</span>
 <span id="L142" class="LineNr">142 </span>  <span class="Delimiter">{</span>
-<span id="L143" class="LineNr">143 </span>    <span class="muControl">break-if</span> next-sandbox
-<span id="L144" class="LineNr">144 </span>    render-from:num <span class="Special">&lt;-</span> get *env, <span class="Constant">render-from:offset</span>
-<span id="L145" class="LineNr">145 </span>    reset-scroll?:bool <span class="Special">&lt;-</span> equal render-from, sandbox-count
-<span id="L146" class="LineNr">146 </span>    <span class="muControl">break-unless</span> reset-scroll?
-<span id="L147" class="LineNr">147 </span>    *env <span class="Special">&lt;-</span> put *env, <span class="Constant">render-from:offset</span>,<span class="Constant"> -1</span>
+<span id="L143" class="LineNr">143 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> next-sandbox
+<span id="L144" class="LineNr">144 </span>  <span class="Conceal">¦</span> render-from:num <span class="Special">&lt;-</span> get *env, <span class="Constant">render-from:offset</span>
+<span id="L145" class="LineNr">145 </span>  <span class="Conceal">¦</span> reset-scroll?:bool <span class="Special">&lt;-</span> equal render-from, sandbox-count
+<span id="L146" class="LineNr">146 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> reset-scroll?
+<span id="L147" class="LineNr">147 </span>  <span class="Conceal">¦</span> *env <span class="Special">&lt;-</span> put *env, <span class="Constant">render-from:offset</span>,<span class="Constant"> -1</span>
 <span id="L148" class="LineNr">148 </span>  <span class="Delimiter">}</span>
 <span id="L149" class="LineNr">149 </span>]
 <span id="L150" class="LineNr">150 </span>
@@ -219,39 +220,39 @@ if ('onhashchange' in window) {
 <span id="L159" class="LineNr">159 </span>  <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
 <span id="L160" class="LineNr">160 </span>  <span class="Comment"># create 2 sandboxes and scroll to second</span>
 <span id="L161" class="LineNr">161 </span>  assume-console [
-<span id="L162" class="LineNr">162 </span>    press ctrl-n
-<span id="L163" class="LineNr">163 </span>    type <span class="Constant">[add 2, 2]</span>
-<span id="L164" class="LineNr">164 </span>    press F4
-<span id="L165" class="LineNr">165 </span>    type <span class="Constant">[add 1, 1]</span>
-<span id="L166" class="LineNr">166 </span>    press F4
-<span id="L167" class="LineNr">167 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L162" class="LineNr">162 </span>  <span class="Conceal">¦</span> press ctrl-n
+<span id="L163" class="LineNr">163 </span>  <span class="Conceal">¦</span> type <span class="Constant">[add 2, 2]</span>
+<span id="L164" class="LineNr">164 </span>  <span class="Conceal">¦</span> press F4
+<span id="L165" class="LineNr">165 </span>  <span class="Conceal">¦</span> type <span class="Constant">[add 1, 1]</span>
+<span id="L166" class="LineNr">166 </span>  <span class="Conceal">¦</span> press F4
+<span id="L167" class="LineNr">167 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L168" class="LineNr">168 </span>  ]
 <span id="L169" class="LineNr">169 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L170" class="LineNr">170 </span>  screen-should-contain [
-<span id="L171" class="LineNr">171 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L172" class="LineNr">172 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L173" class="LineNr">173 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎0   edit          copy            delete         .</span>
-<span id="L174" class="LineNr">174 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L175" class="LineNr">175 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L176" class="LineNr">176 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L177" class="LineNr">177 </span>   <span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
+<span id="L171" class="LineNr">171 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L172" class="LineNr">172 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L173" class="LineNr">173 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎0   edit          copy            delete         .</span>
+<span id="L174" class="LineNr">174 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L175" class="LineNr">175 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L176" class="LineNr">176 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L177" class="LineNr">177 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
 <span id="L178" class="LineNr">178 </span>  ]
 <span id="L179" class="LineNr">179 </span>  <span class="Comment"># delete the second sandbox</span>
 <span id="L180" class="LineNr">180 </span>  assume-console [
-<span id="L181" class="LineNr">181 </span>    left-click<span class="Constant"> 6</span>,<span class="Constant"> 99</span>
+<span id="L181" class="LineNr">181 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 6</span>,<span class="Constant"> 99</span>
 <span id="L182" class="LineNr">182 </span>  ]
 <span id="L183" class="LineNr">183 </span>  run [
-<span id="L184" class="LineNr">184 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L184" class="LineNr">184 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L185" class="LineNr">185 </span>  ]
 <span id="L186" class="LineNr">186 </span>  <span class="Comment"># second sandbox shows in editor; scroll resets to display first sandbox</span>
 <span id="L187" class="LineNr">187 </span>  screen-should-contain [
-<span id="L188" class="LineNr">188 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L189" class="LineNr">189 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L190" class="LineNr">190 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎0   edit          copy            delete         .</span>
-<span id="L191" class="LineNr">191 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L192" class="LineNr">192 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L193" class="LineNr">193 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L194" class="LineNr">194 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L188" class="LineNr">188 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L189" class="LineNr">189 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L190" class="LineNr">190 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎0   edit          copy            delete         .</span>
+<span id="L191" class="LineNr">191 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L192" class="LineNr">192 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L193" class="LineNr">193 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L194" class="LineNr">194 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L195" class="LineNr">195 </span>  ]
 <span id="L196" class="LineNr">196 </span>]
 <span id="L197" class="LineNr">197 </span>
@@ -266,39 +267,39 @@ if ('onhashchange' in window) {
 <span id="L206" class="LineNr">206 </span>  <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
 <span id="L207" class="LineNr">207 </span>  <span class="Comment"># create 2 sandboxes and scroll to second</span>
 <span id="L208" class="LineNr">208 </span>  assume-console [
-<span id="L209" class="LineNr">209 </span>    press ctrl-n
-<span id="L210" class="LineNr">210 </span>    type <span class="Constant">[add 2, 2]</span>
-<span id="L211" class="LineNr">211 </span>    press F4
-<span id="L212" class="LineNr">212 </span>    type <span class="Constant">[add 1, 1]</span>
-<span id="L213" class="LineNr">213 </span>    press F4
-<span id="L214" class="LineNr">214 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L209" class="LineNr">209 </span>  <span class="Conceal">¦</span> press ctrl-n
+<span id="L210" class="LineNr">210 </span>  <span class="Conceal">¦</span> type <span class="Constant">[add 2, 2]</span>
+<span id="L211" class="LineNr">211 </span>  <span class="Conceal">¦</span> press F4
+<span id="L212" class="LineNr">212 </span>  <span class="Conceal">¦</span> type <span class="Constant">[add 1, 1]</span>
+<span id="L213" class="LineNr">213 </span>  <span class="Conceal">¦</span> press F4
+<span id="L214" class="LineNr">214 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L215" class="LineNr">215 </span>  ]
 <span id="L216" class="LineNr">216 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L217" class="LineNr">217 </span>  screen-should-contain [
-<span id="L218" class="LineNr">218 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L219" class="LineNr">219 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L220" class="LineNr">220 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎0   edit          copy            delete         .</span>
-<span id="L221" class="LineNr">221 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L222" class="LineNr">222 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L223" class="LineNr">223 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L224" class="LineNr">224 </span>   <span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
+<span id="L218" class="LineNr">218 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L219" class="LineNr">219 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L220" class="LineNr">220 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎0   edit          copy            delete         .</span>
+<span id="L221" class="LineNr">221 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L222" class="LineNr">222 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L223" class="LineNr">223 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L224" class="LineNr">224 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
 <span id="L225" class="LineNr">225 </span>  ]
 <span id="L226" class="LineNr">226 </span>  <span class="Comment"># delete the second sandbox</span>
 <span id="L227" class="LineNr">227 </span>  assume-console [
-<span id="L228" class="LineNr">228 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 99</span>
+<span id="L228" class="LineNr">228 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 99</span>
 <span id="L229" class="LineNr">229 </span>  ]
 <span id="L230" class="LineNr">230 </span>  run [
-<span id="L231" class="LineNr">231 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L231" class="LineNr">231 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L232" class="LineNr">232 </span>  ]
 <span id="L233" class="LineNr">233 </span>  <span class="Comment"># second sandbox shows in editor; scroll resets to display first sandbox</span>
 <span id="L234" class="LineNr">234 </span>  screen-should-contain [
-<span id="L235" class="LineNr">235 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L236" class="LineNr">236 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L237" class="LineNr">237 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎0   edit          copy            delete         .</span>
-<span id="L238" class="LineNr">238 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L239" class="LineNr">239 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
-<span id="L240" class="LineNr">240 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L241" class="LineNr">241 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L235" class="LineNr">235 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L236" class="LineNr">236 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L237" class="LineNr">237 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎0   edit          copy            delete         .</span>
+<span id="L238" class="LineNr">238 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L239" class="LineNr">239 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L240" class="LineNr">240 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L241" class="LineNr">241 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L242" class="LineNr">242 </span>  ]
 <span id="L243" class="LineNr">243 </span>]
 <span id="L244" class="LineNr">244 </span>
@@ -313,41 +314,41 @@ if ('onhashchange' in window) {
 <span id="L253" class="LineNr">253 </span>  <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
 <span id="L254" class="LineNr">254 </span>  <span class="Comment"># create 2 sandboxes and scroll to second</span>
 <span id="L255" class="LineNr">255 </span>  assume-console [
-<span id="L256" class="LineNr">256 </span>    press ctrl-n
-<span id="L257" class="LineNr">257 </span>    type <span class="Constant">[add 2, 2]</span>
-<span id="L258" class="LineNr">258 </span>    press F4
-<span id="L259" class="LineNr">259 </span>    type <span class="Constant">[add 1, 1]</span>
-<span id="L260" class="LineNr">260 </span>    press F4
-<span id="L261" class="LineNr">261 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
-<span id="L262" class="LineNr">262 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L256" class="LineNr">256 </span>  <span class="Conceal">¦</span> press ctrl-n
+<span id="L257" class="LineNr">257 </span>  <span class="Conceal">¦</span> type <span class="Constant">[add 2, 2]</span>
+<span id="L258" class="LineNr">258 </span>  <span class="Conceal">¦</span> press F4
+<span id="L259" class="LineNr">259 </span>  <span class="Conceal">¦</span> type <span class="Constant">[add 1, 1]</span>
+<span id="L260" class="LineNr">260 </span>  <span class="Conceal">¦</span> press F4
+<span id="L261" class="LineNr">261 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L262" class="LineNr">262 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L263" class="LineNr">263 </span>  ]
 <span id="L264" class="LineNr">264 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L265" class="LineNr">265 </span>  screen-should-contain [
-<span id="L266" class="LineNr">266 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L267" class="LineNr">267 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L268" class="LineNr">268 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎1   edit          copy            delete         .</span>
-<span id="L269" class="LineNr">269 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L270" class="LineNr">270 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
-<span id="L271" class="LineNr">271 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L272" class="LineNr">272 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L266" class="LineNr">266 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L267" class="LineNr">267 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L268" class="LineNr">268 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎1   edit          copy            delete         .</span>
+<span id="L269" class="LineNr">269 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L270" class="LineNr">270 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L271" class="LineNr">271 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L272" class="LineNr">272 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L273" class="LineNr">273 </span>  ]
 <span id="L274" class="LineNr">274 </span>  <span class="Comment"># delete the second sandbox</span>
 <span id="L275" class="LineNr">275 </span>  assume-console [
-<span id="L276" class="LineNr">276 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 99</span>
+<span id="L276" class="LineNr">276 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 99</span>
 <span id="L277" class="LineNr">277 </span>  ]
 <span id="L278" class="LineNr">278 </span>  run [
-<span id="L279" class="LineNr">279 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L279" class="LineNr">279 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L280" class="LineNr">280 </span>  ]
 <span id="L281" class="LineNr">281 </span>  <span class="Comment"># implicitly scroll up to first sandbox</span>
 <span id="L282" class="LineNr">282 </span>  screen-should-contain [
-<span id="L283" class="LineNr">283 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L284" class="LineNr">284 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L285" class="LineNr">285 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L286" class="LineNr">286 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L287" class="LineNr">287 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L288" class="LineNr">288 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L289" class="LineNr">289 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L290" class="LineNr">290 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L283" class="LineNr">283 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L284" class="LineNr">284 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L285" class="LineNr">285 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L286" class="LineNr">286 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L287" class="LineNr">287 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L288" class="LineNr">288 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L289" class="LineNr">289 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L290" class="LineNr">290 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L291" class="LineNr">291 </span>  ]
 <span id="L292" class="LineNr">292 </span>]
 <span id="L293" class="LineNr">293 </span>
@@ -362,43 +363,43 @@ if ('onhashchange' in window) {
 <span id="L302" class="LineNr">302 </span>  <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
 <span id="L303" class="LineNr">303 </span>  <span class="Comment"># create 2 sandboxes</span>
 <span id="L304" class="LineNr">304 </span>  assume-console [
-<span id="L305" class="LineNr">305 </span>    press ctrl-n
-<span id="L306" class="LineNr">306 </span>    type <span class="Constant">[add 2, 2]</span>
-<span id="L307" class="LineNr">307 </span>    press F4
-<span id="L308" class="LineNr">308 </span>    type <span class="Constant">[add 1, 1]</span>
-<span id="L309" class="LineNr">309 </span>    press F4
+<span id="L305" class="LineNr">305 </span>  <span class="Conceal">¦</span> press ctrl-n
+<span id="L306" class="LineNr">306 </span>  <span class="Conceal">¦</span> type <span class="Constant">[add 2, 2]</span>
+<span id="L307" class="LineNr">307 </span>  <span class="Conceal">¦</span> press F4
+<span id="L308" class="LineNr">308 </span>  <span class="Conceal">¦</span> type <span class="Constant">[add 1, 1]</span>
+<span id="L309" class="LineNr">309 </span>  <span class="Conceal">¦</span> press F4
 <span id="L310" class="LineNr">310 </span>  ]
 <span id="L311" class="LineNr">311 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L312" class="LineNr">312 </span>  screen-should-contain [
-<span id="L313" class="LineNr">313 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L314" class="LineNr">314 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L315" class="LineNr">315 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L316" class="LineNr">316 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L317" class="LineNr">317 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L318" class="LineNr">318 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L319" class="LineNr">319 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L320" class="LineNr">320 </span>   <span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
-<span id="L321" class="LineNr">321 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L322" class="LineNr">322 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L313" class="LineNr">313 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L314" class="LineNr">314 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L315" class="LineNr">315 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L316" class="LineNr">316 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L317" class="LineNr">317 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L318" class="LineNr">318 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L319" class="LineNr">319 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L320" class="LineNr">320 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
+<span id="L321" class="LineNr">321 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L322" class="LineNr">322 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
 <span id="L323" class="LineNr">323 </span>  ]
 <span id="L324" class="LineNr">324 </span>  <span class="Comment"># delete the second sandbox, then try to scroll down twice</span>
 <span id="L325" class="LineNr">325 </span>  assume-console [
-<span id="L326" class="LineNr">326 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 99</span>
-<span id="L327" class="LineNr">327 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
-<span id="L328" class="LineNr">328 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L326" class="LineNr">326 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 99</span>
+<span id="L327" class="LineNr">327 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L328" class="LineNr">328 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L329" class="LineNr">329 </span>  ]
 <span id="L330" class="LineNr">330 </span>  run [
-<span id="L331" class="LineNr">331 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L331" class="LineNr">331 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L332" class="LineNr">332 </span>  ]
 <span id="L333" class="LineNr">333 </span>  <span class="Comment"># shouldn't go past last sandbox</span>
 <span id="L334" class="LineNr">334 </span>  screen-should-contain [
-<span id="L335" class="LineNr">335 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L336" class="LineNr">336 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L337" class="LineNr">337 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎0   edit          copy            delete         .</span>
-<span id="L338" class="LineNr">338 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L339" class="LineNr">339 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
-<span id="L340" class="LineNr">340 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L341" class="LineNr">341 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L335" class="LineNr">335 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L336" class="LineNr">336 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L337" class="LineNr">337 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎0   edit          copy            delete         .</span>
+<span id="L338" class="LineNr">338 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L339" class="LineNr">339 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L340" class="LineNr">340 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L341" class="LineNr">341 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L342" class="LineNr">342 </span>  ]
 <span id="L343" class="LineNr">343 </span>]
 </pre>
diff --git a/html/edit/008-sandbox-edit.mu.html b/html/edit/008-sandbox-edit.mu.html
index e253a4c5..e1a3ecc6 100644
--- a/html/edit/008-sandbox-edit.mu.html
+++ b/html/edit/008-sandbox-edit.mu.html
@@ -15,15 +15,16 @@ body { font-size: 12pt; font-family: monospace; color: #eeeeee; background-color
 a { text-decoration: none; }
 a:hover { text-decoration: underline; }
 * { font-size: 12pt; font-size: 1em; }
-.Delimiter { color: #800080; }
-.muControl { color: #c0a020; }
+.Conceal { color: #4e4e4e; }
+.muScenario { color: #00af00; }
 .Special { color: #c00000; }
+.Delimiter { color: #800080; }
 .SalientComment { color: #00ffff; }
 .Constant { color: #00a0a0; }
 .LineNr { color: #444444; }
-.Comment { color: #9090ff; }
 .muRecipe { color: #ff8700; }
-.muScenario { color: #00af00; }
+.Comment { color: #9090ff; }
+.muControl { color: #c0a020; }
 -->
 </style>
 
@@ -70,45 +71,45 @@ if ('onhashchange' in window) {
 <span id="L10" class="LineNr"> 10 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[add 2, 2]</span>
 <span id="L11" class="LineNr"> 11 </span>  <span class="Comment"># run it</span>
 <span id="L12" class="LineNr"> 12 </span>  assume-console [
-<span id="L13" class="LineNr"> 13 </span>    press F4
+<span id="L13" class="LineNr"> 13 </span>  <span class="Conceal">¦</span> press F4
 <span id="L14" class="LineNr"> 14 </span>  ]
 <span id="L15" class="LineNr"> 15 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L16" class="LineNr"> 16 </span>  screen-should-contain [
-<span id="L17" class="LineNr"> 17 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L18" class="LineNr"> 18 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L19" class="LineNr"> 19 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L20" class="LineNr"> 20 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L21" class="LineNr"> 21 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L22" class="LineNr"> 22 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
-<span id="L23" class="LineNr"> 23 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L24" class="LineNr"> 24 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L17" class="LineNr"> 17 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L18" class="LineNr"> 18 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L19" class="LineNr"> 19 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L20" class="LineNr"> 20 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L21" class="LineNr"> 21 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L22" class="LineNr"> 22 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L23" class="LineNr"> 23 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L24" class="LineNr"> 24 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L25" class="LineNr"> 25 </span>  ]
 <span id="L26" class="LineNr"> 26 </span>  <span class="Comment"># click at left edge of 'edit' button</span>
 <span id="L27" class="LineNr"> 27 </span>  assume-console [
-<span id="L28" class="LineNr"> 28 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 55</span>
+<span id="L28" class="LineNr"> 28 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 55</span>
 <span id="L29" class="LineNr"> 29 </span>  ]
 <span id="L30" class="LineNr"> 30 </span>  run [
-<span id="L31" class="LineNr"> 31 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L31" class="LineNr"> 31 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L32" class="LineNr"> 32 </span>  ]
 <span id="L33" class="LineNr"> 33 </span>  <span class="Comment"># it pops back into editor</span>
 <span id="L34" class="LineNr"> 34 </span>  screen-should-contain [
-<span id="L35" class="LineNr"> 35 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L36" class="LineNr"> 36 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L37" class="LineNr"> 37 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L38" class="LineNr"> 38 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L35" class="LineNr"> 35 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L36" class="LineNr"> 36 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L37" class="LineNr"> 37 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L38" class="LineNr"> 38 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L39" class="LineNr"> 39 </span>  ]
 <span id="L40" class="LineNr"> 40 </span>  <span class="Comment"># cursor should be in the right place</span>
 <span id="L41" class="LineNr"> 41 </span>  assume-console [
-<span id="L42" class="LineNr"> 42 </span>    type <span class="Constant">[0]</span>
+<span id="L42" class="LineNr"> 42 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
 <span id="L43" class="LineNr"> 43 </span>  ]
 <span id="L44" class="LineNr"> 44 </span>  run [
-<span id="L45" class="LineNr"> 45 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L45" class="LineNr"> 45 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L46" class="LineNr"> 46 </span>  ]
 <span id="L47" class="LineNr"> 47 </span>  screen-should-contain [
-<span id="L48" class="LineNr"> 48 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L49" class="LineNr"> 49 </span>   <span class="Constant"> .                                                  ╎0add 2, 2                                        .</span>
-<span id="L50" class="LineNr"> 50 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L51" class="LineNr"> 51 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L48" class="LineNr"> 48 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L49" class="LineNr"> 49 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0add 2, 2                                        .</span>
+<span id="L50" class="LineNr"> 50 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L51" class="LineNr"> 51 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L52" class="LineNr"> 52 </span>  ]
 <span id="L53" class="LineNr"> 53 </span>]
 <span id="L54" class="LineNr"> 54 </span>
@@ -122,60 +123,60 @@ if ('onhashchange' in window) {
 <span id="L62" class="LineNr"> 62 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[add 2, 2]</span>
 <span id="L63" class="LineNr"> 63 </span>  <span class="Comment"># run it</span>
 <span id="L64" class="LineNr"> 64 </span>  assume-console [
-<span id="L65" class="LineNr"> 65 </span>    press F4
+<span id="L65" class="LineNr"> 65 </span>  <span class="Conceal">¦</span> press F4
 <span id="L66" class="LineNr"> 66 </span>  ]
 <span id="L67" class="LineNr"> 67 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L68" class="LineNr"> 68 </span>  screen-should-contain [
-<span id="L69" class="LineNr"> 69 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L70" class="LineNr"> 70 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L71" class="LineNr"> 71 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L72" class="LineNr"> 72 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L73" class="LineNr"> 73 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L74" class="LineNr"> 74 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
-<span id="L75" class="LineNr"> 75 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L76" class="LineNr"> 76 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L69" class="LineNr"> 69 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L70" class="LineNr"> 70 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L71" class="LineNr"> 71 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L72" class="LineNr"> 72 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L73" class="LineNr"> 73 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L74" class="LineNr"> 74 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L75" class="LineNr"> 75 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L76" class="LineNr"> 76 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L77" class="LineNr"> 77 </span>  ]
 <span id="L78" class="LineNr"> 78 </span>  <span class="Comment"># click at right edge of 'edit' button (just before 'copy')</span>
 <span id="L79" class="LineNr"> 79 </span>  assume-console [
-<span id="L80" class="LineNr"> 80 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 68</span>
+<span id="L80" class="LineNr"> 80 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 68</span>
 <span id="L81" class="LineNr"> 81 </span>  ]
 <span id="L82" class="LineNr"> 82 </span>  run [
-<span id="L83" class="LineNr"> 83 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L83" class="LineNr"> 83 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L84" class="LineNr"> 84 </span>  ]
 <span id="L85" class="LineNr"> 85 </span>  <span class="Comment"># it pops back into editor</span>
 <span id="L86" class="LineNr"> 86 </span>  screen-should-contain [
-<span id="L87" class="LineNr"> 87 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L88" class="LineNr"> 88 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L89" class="LineNr"> 89 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L90" class="LineNr"> 90 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L87" class="LineNr"> 87 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L88" class="LineNr"> 88 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L89" class="LineNr"> 89 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L90" class="LineNr"> 90 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L91" class="LineNr"> 91 </span>  ]
 <span id="L92" class="LineNr"> 92 </span>  <span class="Comment"># cursor should be in the right place</span>
 <span id="L93" class="LineNr"> 93 </span>  assume-console [
-<span id="L94" class="LineNr"> 94 </span>    type <span class="Constant">[0]</span>
+<span id="L94" class="LineNr"> 94 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
 <span id="L95" class="LineNr"> 95 </span>  ]
 <span id="L96" class="LineNr"> 96 </span>  run [
-<span id="L97" class="LineNr"> 97 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L97" class="LineNr"> 97 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L98" class="LineNr"> 98 </span>  ]
 <span id="L99" class="LineNr"> 99 </span>  screen-should-contain [
-<span id="L100" class="LineNr">100 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L101" class="LineNr">101 </span>   <span class="Constant"> .                                                  ╎0add 2, 2                                        .</span>
-<span id="L102" class="LineNr">102 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L103" class="LineNr">103 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L100" class="LineNr">100 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L101" class="LineNr">101 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0add 2, 2                                        .</span>
+<span id="L102" class="LineNr">102 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L103" class="LineNr">103 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L104" class="LineNr">104 </span>  ]
 <span id="L105" class="LineNr">105 </span>]
 <span id="L106" class="LineNr">106 </span>
 <span id="L107" class="LineNr">107 </span><span class="muRecipe">after</span> <span class="Constant"><a href='004-programming-environment.mu.html#L80'>&lt;global-touch&gt;</a></span> [
 <span id="L108" class="LineNr">108 </span>  <span class="Comment"># support 'edit' button</span>
 <span id="L109" class="LineNr">109 </span>  <span class="Delimiter">{</span>
-<span id="L110" class="LineNr">110 </span>    edit?:bool <span class="Special">&lt;-</span> <a href='008-sandbox-edit.mu.html#L123'>should-attempt-edit?</a> click-row, click-column, env
-<span id="L111" class="LineNr">111 </span>    <span class="muControl">break-unless</span> edit?
-<span id="L112" class="LineNr">112 </span>    edit?, env <span class="Special">&lt;-</span> <a href='008-sandbox-edit.mu.html#L142'>try-edit-sandbox</a> click-row, env
-<span id="L113" class="LineNr">113 </span>    <span class="muControl">break-unless</span> edit?
-<span id="L114" class="LineNr">114 </span>    <a href='../081print.mu.html#L623'>hide-screen</a> <a href='../081print.mu.html#L4'>screen</a>
-<span id="L115" class="LineNr">115 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> render-sandbox-side <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
-<span id="L116" class="LineNr">116 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L511'>update-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, recipes, current-sandbox, sandbox-in-focus?, env
-<span id="L117" class="LineNr">117 </span>    <a href='../081print.mu.html#L631'>show-screen</a> <a href='../081print.mu.html#L4'>screen</a>
-<span id="L118" class="LineNr">118 </span>    <span class="muControl">loop</span> <span class="Constant">+next-event</span>
+<span id="L110" class="LineNr">110 </span>  <span class="Conceal">¦</span> edit?:bool <span class="Special">&lt;-</span> <a href='008-sandbox-edit.mu.html#L123'>should-attempt-edit?</a> click-row, click-column, env
+<span id="L111" class="LineNr">111 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> edit?
+<span id="L112" class="LineNr">112 </span>  <span class="Conceal">¦</span> edit?, env <span class="Special">&lt;-</span> <a href='008-sandbox-edit.mu.html#L142'>try-edit-sandbox</a> click-row, env
+<span id="L113" class="LineNr">113 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> edit?
+<span id="L114" class="LineNr">114 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L623'>hide-screen</a> <a href='../081print.mu.html#L4'>screen</a>
+<span id="L115" class="LineNr">115 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> render-sandbox-side <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
+<span id="L116" class="LineNr">116 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L511'>update-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, recipes, current-sandbox, sandbox-in-focus?, env
+<span id="L117" class="LineNr">117 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L631'>show-screen</a> <a href='../081print.mu.html#L4'>screen</a>
+<span id="L118" class="LineNr">118 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-event</span>
 <span id="L119" class="LineNr">119 </span>  <span class="Delimiter">}</span>
 <span id="L120" class="LineNr">120 </span>]
 <span id="L121" class="LineNr">121 </span>
@@ -228,37 +229,37 @@ if ('onhashchange' in window) {
 <span id="L168" class="LineNr">168 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[print <a href='../081print.mu.html#L4'>screen</a>, 4]</span>
 <span id="L169" class="LineNr">169 </span>  <span class="Comment"># run the sandbox</span>
 <span id="L170" class="LineNr">170 </span>  assume-console [
-<span id="L171" class="LineNr">171 </span>    press F4
+<span id="L171" class="LineNr">171 </span>  <span class="Conceal">¦</span> press F4
 <span id="L172" class="LineNr">172 </span>  ]
 <span id="L173" class="LineNr">173 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L174" class="LineNr">174 </span>  screen-should-contain [
-<span id="L175" class="LineNr">175 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L176" class="LineNr">176 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L177" class="LineNr">177 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L178" class="LineNr">178 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L179" class="LineNr">179 </span>   <span class="Constant"> .                                                  ╎print <a href='../081print.mu.html#L4'>screen</a>, 4                                  .</span>
-<span id="L180" class="LineNr">180 </span>   <span class="Constant"> .                                                  ╎screen:                                          .</span>
-<span id="L181" class="LineNr">181 </span>   <span class="Constant"> .                                                  ╎  .4                             .               .</span>
-<span id="L182" class="LineNr">182 </span>   <span class="Constant"> .                                                  ╎  .                              .               .</span>
-<span id="L183" class="LineNr">183 </span>   <span class="Constant"> .                                                  ╎  .                              .               .</span>
-<span id="L184" class="LineNr">184 </span>   <span class="Constant"> .                                                  ╎  .                              .               .</span>
-<span id="L185" class="LineNr">185 </span>   <span class="Constant"> .                                                  ╎  .                              .               .</span>
-<span id="L186" class="LineNr">186 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L187" class="LineNr">187 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L175" class="LineNr">175 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L176" class="LineNr">176 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L177" class="LineNr">177 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L178" class="LineNr">178 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L179" class="LineNr">179 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎print <a href='../081print.mu.html#L4'>screen</a>, 4                                  .</span>
+<span id="L180" class="LineNr">180 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎screen:                                          .</span>
+<span id="L181" class="LineNr">181 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎  .4                             .               .</span>
+<span id="L182" class="LineNr">182 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎  .                              .               .</span>
+<span id="L183" class="LineNr">183 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎  .                              .               .</span>
+<span id="L184" class="LineNr">184 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎  .                              .               .</span>
+<span id="L185" class="LineNr">185 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎  .                              .               .</span>
+<span id="L186" class="LineNr">186 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L187" class="LineNr">187 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L188" class="LineNr">188 </span>  ]
 <span id="L189" class="LineNr">189 </span>  <span class="Comment"># edit the sandbox</span>
 <span id="L190" class="LineNr">190 </span>  assume-console [
-<span id="L191" class="LineNr">191 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 65</span>
+<span id="L191" class="LineNr">191 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 65</span>
 <span id="L192" class="LineNr">192 </span>  ]
 <span id="L193" class="LineNr">193 </span>  run [
-<span id="L194" class="LineNr">194 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L194" class="LineNr">194 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L195" class="LineNr">195 </span>  ]
 <span id="L196" class="LineNr">196 </span>  screen-should-contain [
-<span id="L197" class="LineNr">197 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L198" class="LineNr">198 </span>   <span class="Constant"> .                                                  ╎print <a href='../081print.mu.html#L4'>screen</a>, 4                                  .</span>
-<span id="L199" class="LineNr">199 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L200" class="LineNr">200 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L201" class="LineNr">201 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L197" class="LineNr">197 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L198" class="LineNr">198 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎print <a href='../081print.mu.html#L4'>screen</a>, 4                                  .</span>
+<span id="L199" class="LineNr">199 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L200" class="LineNr">200 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L201" class="LineNr">201 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L202" class="LineNr">202 </span>  ]
 <span id="L203" class="LineNr">203 </span>]
 <span id="L204" class="LineNr">204 </span>
@@ -273,41 +274,41 @@ if ('onhashchange' in window) {
 <span id="L213" class="LineNr">213 </span>  <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
 <span id="L214" class="LineNr">214 </span>  <span class="Comment"># create 2 sandboxes and scroll to second</span>
 <span id="L215" class="LineNr">215 </span>  assume-console [
-<span id="L216" class="LineNr">216 </span>    press ctrl-n
-<span id="L217" class="LineNr">217 </span>    type <span class="Constant">[add 2, 2]</span>
-<span id="L218" class="LineNr">218 </span>    press F4
-<span id="L219" class="LineNr">219 </span>    type <span class="Constant">[add 1, 1]</span>
-<span id="L220" class="LineNr">220 </span>    press F4
-<span id="L221" class="LineNr">221 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
-<span id="L222" class="LineNr">222 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L216" class="LineNr">216 </span>  <span class="Conceal">¦</span> press ctrl-n
+<span id="L217" class="LineNr">217 </span>  <span class="Conceal">¦</span> type <span class="Constant">[add 2, 2]</span>
+<span id="L218" class="LineNr">218 </span>  <span class="Conceal">¦</span> press F4
+<span id="L219" class="LineNr">219 </span>  <span class="Conceal">¦</span> type <span class="Constant">[add 1, 1]</span>
+<span id="L220" class="LineNr">220 </span>  <span class="Conceal">¦</span> press F4
+<span id="L221" class="LineNr">221 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L222" class="LineNr">222 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L223" class="LineNr">223 </span>  ]
 <span id="L224" class="LineNr">224 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L225" class="LineNr">225 </span>  screen-should-contain [
-<span id="L226" class="LineNr">226 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L227" class="LineNr">227 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L228" class="LineNr">228 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎1   edit          copy            delete         .</span>
-<span id="L229" class="LineNr">229 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L230" class="LineNr">230 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
-<span id="L231" class="LineNr">231 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L232" class="LineNr">232 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L226" class="LineNr">226 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L227" class="LineNr">227 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L228" class="LineNr">228 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎1   edit          copy            delete         .</span>
+<span id="L229" class="LineNr">229 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L230" class="LineNr">230 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L231" class="LineNr">231 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L232" class="LineNr">232 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L233" class="LineNr">233 </span>  ]
 <span id="L234" class="LineNr">234 </span>  <span class="Comment"># edit the second sandbox</span>
 <span id="L235" class="LineNr">235 </span>  assume-console [
-<span id="L236" class="LineNr">236 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 55</span>
+<span id="L236" class="LineNr">236 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 55</span>
 <span id="L237" class="LineNr">237 </span>  ]
 <span id="L238" class="LineNr">238 </span>  run [
-<span id="L239" class="LineNr">239 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L239" class="LineNr">239 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L240" class="LineNr">240 </span>  ]
 <span id="L241" class="LineNr">241 </span>  <span class="Comment"># second sandbox shows in editor; scroll resets to display first sandbox</span>
 <span id="L242" class="LineNr">242 </span>  screen-should-contain [
-<span id="L243" class="LineNr">243 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L244" class="LineNr">244 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L245" class="LineNr">245 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L246" class="LineNr">246 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L247" class="LineNr">247 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L248" class="LineNr">248 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L249" class="LineNr">249 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L250" class="LineNr">250 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L243" class="LineNr">243 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L244" class="LineNr">244 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L245" class="LineNr">245 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L246" class="LineNr">246 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L247" class="LineNr">247 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L248" class="LineNr">248 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L249" class="LineNr">249 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L250" class="LineNr">250 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L251" class="LineNr">251 </span>  ]
 <span id="L252" class="LineNr">252 </span>]
 <span id="L253" class="LineNr">253 </span>
@@ -322,64 +323,64 @@ if ('onhashchange' in window) {
 <span id="L262" class="LineNr">262 </span>  <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
 <span id="L263" class="LineNr">263 </span>  <span class="Comment"># create 2 sandboxes</span>
 <span id="L264" class="LineNr">264 </span>  assume-console [
-<span id="L265" class="LineNr">265 </span>    press ctrl-n
-<span id="L266" class="LineNr">266 </span>    type <span class="Constant">[add 2, 2]</span>
-<span id="L267" class="LineNr">267 </span>    press F4
-<span id="L268" class="LineNr">268 </span>    type <span class="Constant">[add 1, 1]</span>
-<span id="L269" class="LineNr">269 </span>    press F4
+<span id="L265" class="LineNr">265 </span>  <span class="Conceal">¦</span> press ctrl-n
+<span id="L266" class="LineNr">266 </span>  <span class="Conceal">¦</span> type <span class="Constant">[add 2, 2]</span>
+<span id="L267" class="LineNr">267 </span>  <span class="Conceal">¦</span> press F4
+<span id="L268" class="LineNr">268 </span>  <span class="Conceal">¦</span> type <span class="Constant">[add 1, 1]</span>
+<span id="L269" class="LineNr">269 </span>  <span class="Conceal">¦</span> press F4
 <span id="L270" class="LineNr">270 </span>  ]
 <span id="L271" class="LineNr">271 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L272" class="LineNr">272 </span>  screen-should-contain [
-<span id="L273" class="LineNr">273 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L274" class="LineNr">274 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L275" class="LineNr">275 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L276" class="LineNr">276 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L277" class="LineNr">277 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L278" class="LineNr">278 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L279" class="LineNr">279 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L280" class="LineNr">280 </span>   <span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
-<span id="L281" class="LineNr">281 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L282" class="LineNr">282 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L273" class="LineNr">273 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L274" class="LineNr">274 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L275" class="LineNr">275 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L276" class="LineNr">276 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L277" class="LineNr">277 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L278" class="LineNr">278 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L279" class="LineNr">279 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L280" class="LineNr">280 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
+<span id="L281" class="LineNr">281 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L282" class="LineNr">282 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
 <span id="L283" class="LineNr">283 </span>  ]
 <span id="L284" class="LineNr">284 </span>  <span class="Comment"># edit the second sandbox, then resave</span>
 <span id="L285" class="LineNr">285 </span>  assume-console [
-<span id="L286" class="LineNr">286 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 60</span>
-<span id="L287" class="LineNr">287 </span>    press F4
+<span id="L286" class="LineNr">286 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 60</span>
+<span id="L287" class="LineNr">287 </span>  <span class="Conceal">¦</span> press F4
 <span id="L288" class="LineNr">288 </span>  ]
 <span id="L289" class="LineNr">289 </span>  run [
-<span id="L290" class="LineNr">290 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L290" class="LineNr">290 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L291" class="LineNr">291 </span>  ]
 <span id="L292" class="LineNr">292 </span>  <span class="Comment"># no change in contents</span>
 <span id="L293" class="LineNr">293 </span>  screen-should-contain [
-<span id="L294" class="LineNr">294 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L295" class="LineNr">295 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L296" class="LineNr">296 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L297" class="LineNr">297 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L298" class="LineNr">298 </span>   <span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
-<span id="L299" class="LineNr">299 </span>   <span class="Constant"> .                                                  ╎2                                                .</span>
-<span id="L300" class="LineNr">300 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L301" class="LineNr">301 </span>   <span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
-<span id="L302" class="LineNr">302 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L303" class="LineNr">303 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L294" class="LineNr">294 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L295" class="LineNr">295 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L296" class="LineNr">296 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L297" class="LineNr">297 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L298" class="LineNr">298 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 1, 1                                         .</span>
+<span id="L299" class="LineNr">299 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎2                                                .</span>
+<span id="L300" class="LineNr">300 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L301" class="LineNr">301 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎1   edit          copy            delete         .</span>
+<span id="L302" class="LineNr">302 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L303" class="LineNr">303 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
 <span id="L304" class="LineNr">304 </span>  ]
 <span id="L305" class="LineNr">305 </span>  <span class="Comment"># now try to scroll past end</span>
 <span id="L306" class="LineNr">306 </span>  assume-console [
-<span id="L307" class="LineNr">307 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
-<span id="L308" class="LineNr">308 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
-<span id="L309" class="LineNr">309 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L307" class="LineNr">307 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L308" class="LineNr">308 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L309" class="LineNr">309 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L310" class="LineNr">310 </span>  ]
 <span id="L311" class="LineNr">311 </span>  run [
-<span id="L312" class="LineNr">312 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L312" class="LineNr">312 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L313" class="LineNr">313 </span>  ]
 <span id="L314" class="LineNr">314 </span>  <span class="Comment"># screen should show just final sandbox with the right index (1)</span>
 <span id="L315" class="LineNr">315 </span>  screen-should-contain [
-<span id="L316" class="LineNr">316 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L317" class="LineNr">317 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L318" class="LineNr">318 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎1   edit          copy            delete         .</span>
-<span id="L319" class="LineNr">319 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L320" class="LineNr">320 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
-<span id="L321" class="LineNr">321 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L322" class="LineNr">322 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L316" class="LineNr">316 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L317" class="LineNr">317 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L318" class="LineNr">318 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎1   edit          copy            delete         .</span>
+<span id="L319" class="LineNr">319 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L320" class="LineNr">320 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L321" class="LineNr">321 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L322" class="LineNr">322 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L323" class="LineNr">323 </span>  ]
 <span id="L324" class="LineNr">324 </span>]
 </pre>
diff --git a/html/edit/009-sandbox-test.mu.html b/html/edit/009-sandbox-test.mu.html
index 578ffb9f..40dd1013 100644
--- a/html/edit/009-sandbox-test.mu.html
+++ b/html/edit/009-sandbox-test.mu.html
@@ -15,16 +15,17 @@ body { font-size: 12pt; font-family: monospace; color: #eeeeee; background-color
 a { text-decoration: none; }
 a:hover { text-decoration: underline; }
 * { font-size: 12pt; font-size: 1em; }
-.muData { color: #ffff00; }
-.muControl { color: #c0a020; }
+.Conceal { color: #4e4e4e; }
+.muScenario { color: #00af00; }
 .Special { color: #c00000; }
 .Delimiter { color: #800080; }
 .SalientComment { color: #00ffff; }
 .Constant { color: #00a0a0; }
 .LineNr { color: #444444; }
-.Comment { color: #9090ff; }
 .muRecipe { color: #ff8700; }
-.muScenario { color: #00af00; }
+.Comment { color: #9090ff; }
+.muControl { color: #c0a020; }
+.muData { color: #ffff00; }
 -->
 </style>
 
@@ -67,82 +68,82 @@ if ('onhashchange' in window) {
 <span id="L6" class="LineNr">  6 </span>  assume-screen <span class="Constant">100/width</span>, <span class="Constant">10/height</span>
 <span id="L7" class="LineNr">  7 </span>  <span class="Comment"># basic recipe</span>
 <span id="L8" class="LineNr">  8 </span>  assume-resources [
-<span id="L9" class="LineNr">  9 </span>    <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
-<span id="L10" class="LineNr"> 10 </span>      <span class="Constant">|recipe</span> foo <span class="Constant">[|</span>
-<span id="L11" class="LineNr"> 11 </span><span class="Constant">      |  reply 4|</span>
-<span id="L12" class="LineNr"> 12 </span><span class="Constant">      |]</span>|
-<span id="L13" class="LineNr"> 13 </span>    ]
+<span id="L9" class="LineNr">  9 </span>  <span class="Conceal">¦</span> <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
+<span id="L10" class="LineNr"> 10 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Constant">|recipe</span> foo <span class="Constant">[|</span>
+<span id="L11" class="LineNr"> 11 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  reply 4|</span>
+<span id="L12" class="LineNr"> 12 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |]</span>|
+<span id="L13" class="LineNr"> 13 </span>  <span class="Conceal">¦</span> ]
 <span id="L14" class="LineNr"> 14 </span>  ]
 <span id="L15" class="LineNr"> 15 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[foo]</span>
 <span id="L16" class="LineNr"> 16 </span>  <span class="Comment"># run it</span>
 <span id="L17" class="LineNr"> 17 </span>  assume-console [
-<span id="L18" class="LineNr"> 18 </span>    press F4
+<span id="L18" class="LineNr"> 18 </span>  <span class="Conceal">¦</span> press F4
 <span id="L19" class="LineNr"> 19 </span>  ]
 <span id="L20" class="LineNr"> 20 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L21" class="LineNr"> 21 </span>  screen-should-contain [
-<span id="L22" class="LineNr"> 22 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L23" class="LineNr"> 23 </span>   <span class="Constant"> .recipe foo [                                      ╎                                                 .</span>
-<span id="L24" class="LineNr"> 24 </span>   <span class="Constant"> .  reply 4                                         ╎─────────────────────────────────────────────────.</span>
-<span id="L25" class="LineNr"> 25 </span>   <span class="Constant"> .]                                                 ╎0   edit          copy            delete         .</span>
-<span id="L26" class="LineNr"> 26 </span>   <span class="Constant"> .                                                  ╎foo                                              .</span>
-<span id="L27" class="LineNr"> 27 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎4                                                .</span>
-<span id="L28" class="LineNr"> 28 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L29" class="LineNr"> 29 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L22" class="LineNr"> 22 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L23" class="LineNr"> 23 </span>  <span class="Conceal">¦</span><span class="Constant"> .recipe foo [                                      ╎                                                 .</span>
+<span id="L24" class="LineNr"> 24 </span>  <span class="Conceal">¦</span><span class="Constant"> .  reply 4                                         ╎─────────────────────────────────────────────────.</span>
+<span id="L25" class="LineNr"> 25 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎0   edit          copy            delete         .</span>
+<span id="L26" class="LineNr"> 26 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎foo                                              .</span>
+<span id="L27" class="LineNr"> 27 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎4                                                .</span>
+<span id="L28" class="LineNr"> 28 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L29" class="LineNr"> 29 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L30" class="LineNr"> 30 </span>  ]
 <span id="L31" class="LineNr"> 31 </span>  <span class="Comment"># click on the '4' in the result</span>
 <span id="L32" class="LineNr"> 32 </span>  assume-console [
-<span id="L33" class="LineNr"> 33 </span>    left-click<span class="Constant"> 5</span>,<span class="Constant"> 51</span>
+<span id="L33" class="LineNr"> 33 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 5</span>,<span class="Constant"> 51</span>
 <span id="L34" class="LineNr"> 34 </span>  ]
 <span id="L35" class="LineNr"> 35 </span>  run [
-<span id="L36" class="LineNr"> 36 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L36" class="LineNr"> 36 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L37" class="LineNr"> 37 </span>  ]
 <span id="L38" class="LineNr"> 38 </span>  <span class="Comment"># color toggles to green</span>
 <span id="L39" class="LineNr"> 39 </span>  screen-should-contain-in-color <span class="Constant">2/green</span>, [
-<span id="L40" class="LineNr"> 40 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L41" class="LineNr"> 41 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L42" class="LineNr"> 42 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L43" class="LineNr"> 43 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L44" class="LineNr"> 44 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L45" class="LineNr"> 45 </span>   <span class="Constant"> .                                                   4                                                .</span>
-<span id="L46" class="LineNr"> 46 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L47" class="LineNr"> 47 </span>   <span class="Constant"> .                                                                                                    .</span>
+<span id="L40" class="LineNr"> 40 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L41" class="LineNr"> 41 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L42" class="LineNr"> 42 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L43" class="LineNr"> 43 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L44" class="LineNr"> 44 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L45" class="LineNr"> 45 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                   4                                                .</span>
+<span id="L46" class="LineNr"> 46 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L47" class="LineNr"> 47 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
 <span id="L48" class="LineNr"> 48 </span>  ]
 <span id="L49" class="LineNr"> 49 </span>  <span class="Comment"># cursor should remain unmoved</span>
 <span id="L50" class="LineNr"> 50 </span>  run [
-<span id="L51" class="LineNr"> 51 </span>    cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
-<span id="L52" class="LineNr"> 52 </span>    print <a href='../081print.mu.html#L4'>screen</a>, cursor
+<span id="L51" class="LineNr"> 51 </span>  <span class="Conceal">¦</span> cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
+<span id="L52" class="LineNr"> 52 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, cursor
 <span id="L53" class="LineNr"> 53 </span>  ]
 <span id="L54" class="LineNr"> 54 </span>  screen-should-contain [
-<span id="L55" class="LineNr"> 55 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L56" class="LineNr"> 56 </span>   <span class="Constant"> .␣ecipe foo [                                      ╎                                                 .</span>
-<span id="L57" class="LineNr"> 57 </span>   <span class="Constant"> .  reply 4                                         ╎─────────────────────────────────────────────────.</span>
-<span id="L58" class="LineNr"> 58 </span>   <span class="Constant"> .]                                                 ╎0   edit          copy            delete         .</span>
-<span id="L59" class="LineNr"> 59 </span>   <span class="Constant"> .                                                  ╎foo                                              .</span>
-<span id="L60" class="LineNr"> 60 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎4                                                .</span>
-<span id="L61" class="LineNr"> 61 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L62" class="LineNr"> 62 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L55" class="LineNr"> 55 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L56" class="LineNr"> 56 </span>  <span class="Conceal">¦</span><span class="Constant"> .␣ecipe foo [                                      ╎                                                 .</span>
+<span id="L57" class="LineNr"> 57 </span>  <span class="Conceal">¦</span><span class="Constant"> .  reply 4                                         ╎─────────────────────────────────────────────────.</span>
+<span id="L58" class="LineNr"> 58 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎0   edit          copy            delete         .</span>
+<span id="L59" class="LineNr"> 59 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎foo                                              .</span>
+<span id="L60" class="LineNr"> 60 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎4                                                .</span>
+<span id="L61" class="LineNr"> 61 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L62" class="LineNr"> 62 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L63" class="LineNr"> 63 </span>  ]
 <span id="L64" class="LineNr"> 64 </span>  <span class="Comment"># now change the result</span>
 <span id="L65" class="LineNr"> 65 </span>  <span class="Comment"># then rerun</span>
 <span id="L66" class="LineNr"> 66 </span>  assume-console [
-<span id="L67" class="LineNr"> 67 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 11</span>  <span class="Comment"># cursor to end of line</span>
-<span id="L68" class="LineNr"> 68 </span>    press backspace
-<span id="L69" class="LineNr"> 69 </span>    type <span class="Constant">[3]</span>
-<span id="L70" class="LineNr"> 70 </span>    press F4
+<span id="L67" class="LineNr"> 67 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 11</span>  <span class="Comment"># cursor to end of line</span>
+<span id="L68" class="LineNr"> 68 </span>  <span class="Conceal">¦</span> press backspace
+<span id="L69" class="LineNr"> 69 </span>  <span class="Conceal">¦</span> type <span class="Constant">[3]</span>
+<span id="L70" class="LineNr"> 70 </span>  <span class="Conceal">¦</span> press F4
 <span id="L71" class="LineNr"> 71 </span>  ]
 <span id="L72" class="LineNr"> 72 </span>  run [
-<span id="L73" class="LineNr"> 73 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L73" class="LineNr"> 73 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L74" class="LineNr"> 74 </span>  ]
 <span id="L75" class="LineNr"> 75 </span>  <span class="Comment"># result turns red</span>
 <span id="L76" class="LineNr"> 76 </span>  screen-should-contain-in-color <span class="Constant">1/red</span>, [
-<span id="L77" class="LineNr"> 77 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L78" class="LineNr"> 78 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L79" class="LineNr"> 79 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L80" class="LineNr"> 80 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L81" class="LineNr"> 81 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L82" class="LineNr"> 82 </span>   <span class="Constant"> .                                                   3                                                .</span>
-<span id="L83" class="LineNr"> 83 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L84" class="LineNr"> 84 </span>   <span class="Constant"> .                                                                                                    .</span>
+<span id="L77" class="LineNr"> 77 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L78" class="LineNr"> 78 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L79" class="LineNr"> 79 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L80" class="LineNr"> 80 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L81" class="LineNr"> 81 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L82" class="LineNr"> 82 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                   3                                                .</span>
+<span id="L83" class="LineNr"> 83 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L84" class="LineNr"> 84 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
 <span id="L85" class="LineNr"> 85 </span>  ]
 <span id="L86" class="LineNr"> 86 </span>]
 <span id="L87" class="LineNr"> 87 </span>
@@ -155,19 +156,19 @@ if ('onhashchange' in window) {
 <span id="L94" class="LineNr"> 94 </span><span class="Comment"># include expected response when saving or restoring a sandbox</span>
 <span id="L95" class="LineNr"> 95 </span><span class="muRecipe">before</span> <span class="Constant"><a href='005-sandbox.mu.html#L228'>&lt;end-save-sandbox&gt;</a></span> [
 <span id="L96" class="LineNr"> 96 </span>  <span class="Delimiter">{</span>
-<span id="L97" class="LineNr"> 97 </span>    expected-response:text <span class="Special">&lt;-</span> get *curr, <span class="Constant">expected-response:offset</span>
-<span id="L98" class="LineNr"> 98 </span>    <span class="muControl">break-unless</span> expected-response
-<span id="L99" class="LineNr"> 99 </span>    filename <span class="Special">&lt;-</span> append filename, <span class="Constant">[.out]</span>
-<span id="L100" class="LineNr">100 </span>    <a href='../088file.mu.html#L11'>resources</a> <span class="Special">&lt;-</span> <a href='../088file.mu.html#L127'>dump</a> <a href='../088file.mu.html#L11'>resources</a>, filename, expected-response
+<span id="L97" class="LineNr"> 97 </span>  <span class="Conceal">¦</span> expected-response:text <span class="Special">&lt;-</span> get *curr, <span class="Constant">expected-response:offset</span>
+<span id="L98" class="LineNr"> 98 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> expected-response
+<span id="L99" class="LineNr"> 99 </span>  <span class="Conceal">¦</span> filename <span class="Special">&lt;-</span> append filename, <span class="Constant">[.out]</span>
+<span id="L100" class="LineNr">100 </span>  <span class="Conceal">¦</span> <a href='../088file.mu.html#L11'>resources</a> <span class="Special">&lt;-</span> <a href='../088file.mu.html#L127'>dump</a> <a href='../088file.mu.html#L11'>resources</a>, filename, expected-response
 <span id="L101" class="LineNr">101 </span>  <span class="Delimiter">}</span>
 <span id="L102" class="LineNr">102 </span>]
 <span id="L103" class="LineNr">103 </span>
 <span id="L104" class="LineNr">104 </span><span class="muRecipe">before</span> <span class="Constant"><a href='005-sandbox.mu.html#L432'>&lt;end-restore-sandbox&gt;</a></span> [
 <span id="L105" class="LineNr">105 </span>  <span class="Delimiter">{</span>
-<span id="L106" class="LineNr">106 </span>    filename <span class="Special">&lt;-</span> append filename, <span class="Constant">[.out]</span>
-<span id="L107" class="LineNr">107 </span>    contents <span class="Special">&lt;-</span> <a href='../088file.mu.html#L38'>slurp</a> <a href='../088file.mu.html#L11'>resources</a>, filename
-<span id="L108" class="LineNr">108 </span>    <span class="muControl">break-unless</span> contents
-<span id="L109" class="LineNr">109 </span>    *curr <span class="Special">&lt;-</span> put *curr, <span class="Constant">expected-response:offset</span>, contents
+<span id="L106" class="LineNr">106 </span>  <span class="Conceal">¦</span> filename <span class="Special">&lt;-</span> append filename, <span class="Constant">[.out]</span>
+<span id="L107" class="LineNr">107 </span>  <span class="Conceal">¦</span> contents <span class="Special">&lt;-</span> <a href='../088file.mu.html#L38'>slurp</a> <a href='../088file.mu.html#L11'>resources</a>, filename
+<span id="L108" class="LineNr">108 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> contents
+<span id="L109" class="LineNr">109 </span>  <span class="Conceal">¦</span> *curr <span class="Special">&lt;-</span> put *curr, <span class="Constant">expected-response:offset</span>, contents
 <span id="L110" class="LineNr">110 </span>  <span class="Delimiter">}</span>
 <span id="L111" class="LineNr">111 </span>]
 <span id="L112" class="LineNr">112 </span>
@@ -175,28 +176,28 @@ if ('onhashchange' in window) {
 <span id="L114" class="LineNr">114 </span><span class="muRecipe">after</span> <span class="Constant"><a href='004-programming-environment.mu.html#L80'>&lt;global-touch&gt;</a></span> [
 <span id="L115" class="LineNr">115 </span>  <span class="Comment"># check if it's inside the output of any sandbox</span>
 <span id="L116" class="LineNr">116 </span>  <span class="Delimiter">{</span>
-<span id="L117" class="LineNr">117 </span>    sandbox-left-margin:num <span class="Special">&lt;-</span> get *current-sandbox, <span class="Constant">left:offset</span>
-<span id="L118" class="LineNr">118 </span>    click-column:num <span class="Special">&lt;-</span> get t, <span class="Constant">column:offset</span>
-<span id="L119" class="LineNr">119 </span>    on-sandbox-side?:bool <span class="Special">&lt;-</span> greater-or-equal click-column, sandbox-left-margin
-<span id="L120" class="LineNr">120 </span>    <span class="muControl">break-unless</span> on-sandbox-side?
-<span id="L121" class="LineNr">121 </span>    first-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *env, <span class="Constant">sandbox:offset</span>
-<span id="L122" class="LineNr">122 </span>    <span class="muControl">break-unless</span> first-sandbox
-<span id="L123" class="LineNr">123 </span>    first-sandbox-begins:num <span class="Special">&lt;-</span> get *first-sandbox, <span class="Constant">starting-row-on-screen:offset</span>
-<span id="L124" class="LineNr">124 </span>    click-row:num <span class="Special">&lt;-</span> get t, <span class="Constant">row:offset</span>
-<span id="L125" class="LineNr">125 </span>    below-sandbox-editor?:bool <span class="Special">&lt;-</span> greater-or-equal click-row, first-sandbox-begins
-<span id="L126" class="LineNr">126 </span>    <span class="muControl">break-unless</span> below-sandbox-editor?
-<span id="L127" class="LineNr">127 </span>    <span class="Comment"># identify the sandbox whose output is being clicked on</span>
-<span id="L128" class="LineNr">128 </span>    sandbox:&amp;:sandbox <span class="Special">&lt;-</span> <a href='009-sandbox-test.mu.html#L142'>find-click-in-sandbox-output</a> env, click-row
-<span id="L129" class="LineNr">129 </span>    <span class="muControl">break-unless</span> sandbox
-<span id="L130" class="LineNr">130 </span>    <span class="Comment"># toggle its expected-response, and save session</span>
-<span id="L131" class="LineNr">131 </span>    sandbox <span class="Special">&lt;-</span> <a href='009-sandbox-test.mu.html#L168'>toggle-expected-response</a> sandbox
-<span id="L132" class="LineNr">132 </span>    <a href='005-sandbox.mu.html#L215'>save-sandboxes</a> env, <a href='../088file.mu.html#L11'>resources</a>
-<span id="L133" class="LineNr">133 </span>    <a href='../081print.mu.html#L623'>hide-screen</a> <a href='../081print.mu.html#L4'>screen</a>
-<span id="L134" class="LineNr">134 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> render-sandbox-side <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
-<span id="L135" class="LineNr">135 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L511'>update-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, recipes, current-sandbox, sandbox-in-focus?, env
-<span id="L136" class="LineNr">136 </span>    <span class="Comment"># no change in cursor</span>
-<span id="L137" class="LineNr">137 </span>    <a href='../081print.mu.html#L631'>show-screen</a> <a href='../081print.mu.html#L4'>screen</a>
-<span id="L138" class="LineNr">138 </span>    <span class="muControl">loop</span> <span class="Constant">+next-event</span>
+<span id="L117" class="LineNr">117 </span>  <span class="Conceal">¦</span> sandbox-left-margin:num <span class="Special">&lt;-</span> get *current-sandbox, <span class="Constant">left:offset</span>
+<span id="L118" class="LineNr">118 </span>  <span class="Conceal">¦</span> click-column:num <span class="Special">&lt;-</span> get t, <span class="Constant">column:offset</span>
+<span id="L119" class="LineNr">119 </span>  <span class="Conceal">¦</span> on-sandbox-side?:bool <span class="Special">&lt;-</span> greater-or-equal click-column, sandbox-left-margin
+<span id="L120" class="LineNr">120 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> on-sandbox-side?
+<span id="L121" class="LineNr">121 </span>  <span class="Conceal">¦</span> first-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *env, <span class="Constant">sandbox:offset</span>
+<span id="L122" class="LineNr">122 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> first-sandbox
+<span id="L123" class="LineNr">123 </span>  <span class="Conceal">¦</span> first-sandbox-begins:num <span class="Special">&lt;-</span> get *first-sandbox, <span class="Constant">starting-row-on-screen:offset</span>
+<span id="L124" class="LineNr">124 </span>  <span class="Conceal">¦</span> click-row:num <span class="Special">&lt;-</span> get t, <span class="Constant">row:offset</span>
+<span id="L125" class="LineNr">125 </span>  <span class="Conceal">¦</span> below-sandbox-editor?:bool <span class="Special">&lt;-</span> greater-or-equal click-row, first-sandbox-begins
+<span id="L126" class="LineNr">126 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> below-sandbox-editor?
+<span id="L127" class="LineNr">127 </span>  <span class="Conceal">¦</span> <span class="Comment"># identify the sandbox whose output is being clicked on</span>
+<span id="L128" class="LineNr">128 </span>  <span class="Conceal">¦</span> sandbox:&amp;:sandbox <span class="Special">&lt;-</span> <a href='009-sandbox-test.mu.html#L142'>find-click-in-sandbox-output</a> env, click-row
+<span id="L129" class="LineNr">129 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> sandbox
+<span id="L130" class="LineNr">130 </span>  <span class="Conceal">¦</span> <span class="Comment"># toggle its expected-response, and save session</span>
+<span id="L131" class="LineNr">131 </span>  <span class="Conceal">¦</span> sandbox <span class="Special">&lt;-</span> <a href='009-sandbox-test.mu.html#L168'>toggle-expected-response</a> sandbox
+<span id="L132" class="LineNr">132 </span>  <span class="Conceal">¦</span> <a href='005-sandbox.mu.html#L215'>save-sandboxes</a> env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L133" class="LineNr">133 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L623'>hide-screen</a> <a href='../081print.mu.html#L4'>screen</a>
+<span id="L134" class="LineNr">134 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> render-sandbox-side <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
+<span id="L135" class="LineNr">135 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L511'>update-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, recipes, current-sandbox, sandbox-in-focus?, env
+<span id="L136" class="LineNr">136 </span>  <span class="Conceal">¦</span> <span class="Comment"># no change in cursor</span>
+<span id="L137" class="LineNr">137 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L631'>show-screen</a> <a href='../081print.mu.html#L4'>screen</a>
+<span id="L138" class="LineNr">138 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-event</span>
 <span id="L139" class="LineNr">139 </span>  <span class="Delimiter">}</span>
 <span id="L140" class="LineNr">140 </span>]
 <span id="L141" class="LineNr">141 </span>
@@ -210,13 +211,13 @@ if ('onhashchange' in window) {
 <span id="L149" class="LineNr">149 </span>  assert clicked-on-sandboxes?, <span class="Constant">[extract-sandbox called on click to sandbox editor]</span>
 <span id="L150" class="LineNr">150 </span>  <span class="Comment"># while click-row &lt; sandbox.next-sandbox.starting-row-on-screen</span>
 <span id="L151" class="LineNr">151 </span>  <span class="Delimiter">{</span>
-<span id="L152" class="LineNr">152 </span>    next-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">next-sandbox:offset</span>
-<span id="L153" class="LineNr">153 </span>    <span class="muControl">break-unless</span> next-sandbox
-<span id="L154" class="LineNr">154 </span>    next-start:num <span class="Special">&lt;-</span> get *next-sandbox, <span class="Constant">starting-row-on-screen:offset</span>
-<span id="L155" class="LineNr">155 </span>    found?:bool <span class="Special">&lt;-</span> lesser-than click-row, next-start
-<span id="L156" class="LineNr">156 </span>    <span class="muControl">break-if</span> found?
-<span id="L157" class="LineNr">157 </span>    sandbox <span class="Special">&lt;-</span> copy next-sandbox
-<span id="L158" class="LineNr">158 </span>    <span class="muControl">loop</span>
+<span id="L152" class="LineNr">152 </span>  <span class="Conceal">¦</span> next-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">next-sandbox:offset</span>
+<span id="L153" class="LineNr">153 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> next-sandbox
+<span id="L154" class="LineNr">154 </span>  <span class="Conceal">¦</span> next-start:num <span class="Special">&lt;-</span> get *next-sandbox, <span class="Constant">starting-row-on-screen:offset</span>
+<span id="L155" class="LineNr">155 </span>  <span class="Conceal">¦</span> found?:bool <span class="Special">&lt;-</span> lesser-than click-row, next-start
+<span id="L156" class="LineNr">156 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> found?
+<span id="L157" class="LineNr">157 </span>  <span class="Conceal">¦</span> sandbox <span class="Special">&lt;-</span> copy next-sandbox
+<span id="L158" class="LineNr">158 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L159" class="LineNr">159 </span>  <span class="Delimiter">}</span>
 <span id="L160" class="LineNr">160 </span>  <span class="Comment"># return sandbox if click is in its output region</span>
 <span id="L161" class="LineNr">161 </span>  response-starting-row:num <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">response-starting-row-on-screen:offset</span>
@@ -231,35 +232,35 @@ if ('onhashchange' in window) {
 <span id="L170" class="LineNr">170 </span>  <span class="Constant">load-ingredients</span>
 <span id="L171" class="LineNr">171 </span>  expected-response:text <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">expected-response:offset</span>
 <span id="L172" class="LineNr">172 </span>  <span class="Delimiter">{</span>
-<span id="L173" class="LineNr">173 </span>    <span class="Comment"># if expected-response is set, reset</span>
-<span id="L174" class="LineNr">174 </span>    <span class="muControl">break-unless</span> expected-response
-<span id="L175" class="LineNr">175 </span>    *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">expected-response:offset</span>,<span class="Constant"> 0</span>
+<span id="L173" class="LineNr">173 </span>  <span class="Conceal">¦</span> <span class="Comment"># if expected-response is set, reset</span>
+<span id="L174" class="LineNr">174 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> expected-response
+<span id="L175" class="LineNr">175 </span>  <span class="Conceal">¦</span> *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">expected-response:offset</span>,<span class="Constant"> 0</span>
 <span id="L176" class="LineNr">176 </span>  <span class="Delimiter">}</span>
 <span id="L177" class="LineNr">177 </span>  <span class="Delimiter">{</span>
-<span id="L178" class="LineNr">178 </span>    <span class="Comment"># if not, set expected response to the current response</span>
-<span id="L179" class="LineNr">179 </span>    <span class="muControl">break-if</span> expected-response
-<span id="L180" class="LineNr">180 </span>    response:text <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">response:offset</span>
-<span id="L181" class="LineNr">181 </span>    *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">expected-response:offset</span>, response
+<span id="L178" class="LineNr">178 </span>  <span class="Conceal">¦</span> <span class="Comment"># if not, set expected response to the current response</span>
+<span id="L179" class="LineNr">179 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> expected-response
+<span id="L180" class="LineNr">180 </span>  <span class="Conceal">¦</span> response:text <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">response:offset</span>
+<span id="L181" class="LineNr">181 </span>  <span class="Conceal">¦</span> *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">expected-response:offset</span>, response
 <span id="L182" class="LineNr">182 </span>  <span class="Delimiter">}</span>
 <span id="L183" class="LineNr">183 </span>]
 <span id="L184" class="LineNr">184 </span>
 <span id="L185" class="LineNr">185 </span><span class="Comment"># when rendering a sandbox, color it in red/green if expected response exists</span>
 <span id="L186" class="LineNr">186 </span><span class="muRecipe">after</span> <span class="Constant"><a href='005-sandbox.mu.html#L292'>&lt;render-sandbox-response&gt;</a></span> [
 <span id="L187" class="LineNr">187 </span>  <span class="Delimiter">{</span>
-<span id="L188" class="LineNr">188 </span>    <span class="muControl">break-unless</span> sandbox-response
-<span id="L189" class="LineNr">189 </span>    *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">response-starting-row-on-screen:offset</span>, row
-<span id="L190" class="LineNr">190 </span>    expected-response:text <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">expected-response:offset</span>
-<span id="L191" class="LineNr">191 </span>    <span class="muControl">break-unless</span> expected-response  <span class="Comment"># fall-through to print in grey</span>
-<span id="L192" class="LineNr">192 </span>    response-is-expected?:bool <span class="Special">&lt;-</span> equal expected-response, sandbox-response
-<span id="L193" class="LineNr">193 </span>    <span class="Delimiter">{</span>
-<span id="L194" class="LineNr">194 </span>      <span class="muControl">break-if</span> response-is-expected?:bool
-<span id="L195" class="LineNr">195 </span>      row, <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L356'>render-text</a> <a href='../081print.mu.html#L4'>screen</a>, sandbox-response, left, right, <span class="Constant">1/red</span>, row
-<span id="L196" class="LineNr">196 </span>    <span class="Delimiter">}</span>
-<span id="L197" class="LineNr">197 </span>    <span class="Delimiter">{</span>
-<span id="L198" class="LineNr">198 </span>      <span class="muControl">break-unless</span> response-is-expected?:bool
-<span id="L199" class="LineNr">199 </span>      row, <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L356'>render-text</a> <a href='../081print.mu.html#L4'>screen</a>, sandbox-response, left, right, <span class="Constant">2/green</span>, row
-<span id="L200" class="LineNr">200 </span>    <span class="Delimiter">}</span>
-<span id="L201" class="LineNr">201 </span>    <span class="muControl">jump</span> <span class="Constant">+render-sandbox-end</span>
+<span id="L188" class="LineNr">188 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> sandbox-response
+<span id="L189" class="LineNr">189 </span>  <span class="Conceal">¦</span> *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">response-starting-row-on-screen:offset</span>, row
+<span id="L190" class="LineNr">190 </span>  <span class="Conceal">¦</span> expected-response:text <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">expected-response:offset</span>
+<span id="L191" class="LineNr">191 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> expected-response  <span class="Comment"># fall-through to print in grey</span>
+<span id="L192" class="LineNr">192 </span>  <span class="Conceal">¦</span> response-is-expected?:bool <span class="Special">&lt;-</span> equal expected-response, sandbox-response
+<span id="L193" class="LineNr">193 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L194" class="LineNr">194 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> response-is-expected?:bool
+<span id="L195" class="LineNr">195 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> row, <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L356'>render-text</a> <a href='../081print.mu.html#L4'>screen</a>, sandbox-response, left, right, <span class="Constant">1/red</span>, row
+<span id="L196" class="LineNr">196 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L197" class="LineNr">197 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L198" class="LineNr">198 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> response-is-expected?:bool
+<span id="L199" class="LineNr">199 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> row, <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L356'>render-text</a> <a href='../081print.mu.html#L4'>screen</a>, sandbox-response, left, right, <span class="Constant">2/green</span>, row
+<span id="L200" class="LineNr">200 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L201" class="LineNr">201 </span>  <span class="Conceal">¦</span> <span class="muControl">jump</span> <span class="Constant">+render-sandbox-end</span>
 <span id="L202" class="LineNr">202 </span>  <span class="Delimiter">}</span>
 <span id="L203" class="LineNr">203 </span>]
 <span id="L204" class="LineNr">204 </span>
diff --git a/html/edit/010-sandbox-trace.mu.html b/html/edit/010-sandbox-trace.mu.html
index caafdea5..99709a40 100644
--- a/html/edit/010-sandbox-trace.mu.html
+++ b/html/edit/010-sandbox-trace.mu.html
@@ -15,16 +15,17 @@ body { font-size: 12pt; font-family: monospace; color: #eeeeee; background-color
 a { text-decoration: none; }
 a:hover { text-decoration: underline; }
 * { font-size: 12pt; font-size: 1em; }
-.muData { color: #ffff00; }
-.muControl { color: #c0a020; }
+.Conceal { color: #4e4e4e; }
+.muScenario { color: #00af00; }
 .Special { color: #c00000; }
 .Delimiter { color: #800080; }
 .SalientComment { color: #00ffff; }
 .Constant { color: #00a0a0; }
 .LineNr { color: #444444; }
-.Comment { color: #9090ff; }
 .muRecipe { color: #ff8700; }
-.muScenario { color: #00af00; }
+.Comment { color: #9090ff; }
+.muControl { color: #c0a020; }
+.muData { color: #ffff00; }
 -->
 </style>
 
@@ -67,70 +68,70 @@ if ('onhashchange' in window) {
 <span id="L6" class="LineNr">  6 </span>  assume-screen <span class="Constant">100/width</span>, <span class="Constant">10/height</span>
 <span id="L7" class="LineNr">  7 </span>  <span class="Comment"># basic recipe</span>
 <span id="L8" class="LineNr">  8 </span>  assume-resources [
-<span id="L9" class="LineNr">  9 </span>    <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
-<span id="L10" class="LineNr"> 10 </span>      <span class="Constant">|recipe</span> foo <span class="Constant">[|</span>
-<span id="L11" class="LineNr"> 11 </span><span class="Constant">      |  stash [abc]</span>|
-<span id="L12" class="LineNr"> 12 </span><span class="Constant">      |]|</span>
-<span id="L13" class="LineNr"> 13 </span>    ]
+<span id="L9" class="LineNr">  9 </span>  <span class="Conceal">¦</span> <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
+<span id="L10" class="LineNr"> 10 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Constant">|recipe</span> foo <span class="Constant">[|</span>
+<span id="L11" class="LineNr"> 11 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  stash [abc]</span>|
+<span id="L12" class="LineNr"> 12 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |]|</span>
+<span id="L13" class="LineNr"> 13 </span>  <span class="Conceal">¦</span> ]
 <span id="L14" class="LineNr"> 14 </span>  ]
 <span id="L15" class="LineNr"> 15 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[foo]</span>
 <span id="L16" class="LineNr"> 16 </span>  <span class="Comment"># run it</span>
 <span id="L17" class="LineNr"> 17 </span>  assume-console [
-<span id="L18" class="LineNr"> 18 </span>    press F4
+<span id="L18" class="LineNr"> 18 </span>  <span class="Conceal">¦</span> press F4
 <span id="L19" class="LineNr"> 19 </span>  ]
 <span id="L20" class="LineNr"> 20 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L21" class="LineNr"> 21 </span>  screen-should-contain [
-<span id="L22" class="LineNr"> 22 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L23" class="LineNr"> 23 </span>   <span class="Constant"> .recipe foo [                                      ╎                                                 .</span>
-<span id="L24" class="LineNr"> 24 </span>   <span class="Constant"> .  stash [abc]                                     ╎─────────────────────────────────────────────────.</span>
-<span id="L25" class="LineNr"> 25 </span>   <span class="Constant"> .]                                                 ╎0   edit          copy            delete         .</span>
-<span id="L26" class="LineNr"> 26 </span>   <span class="Constant"> .                                                  ╎foo                                              .</span>
-<span id="L27" class="LineNr"> 27 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L28" class="LineNr"> 28 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L22" class="LineNr"> 22 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L23" class="LineNr"> 23 </span>  <span class="Conceal">¦</span><span class="Constant"> .recipe foo [                                      ╎                                                 .</span>
+<span id="L24" class="LineNr"> 24 </span>  <span class="Conceal">¦</span><span class="Constant"> .  stash [abc]                                     ╎─────────────────────────────────────────────────.</span>
+<span id="L25" class="LineNr"> 25 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎0   edit          copy            delete         .</span>
+<span id="L26" class="LineNr"> 26 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎foo                                              .</span>
+<span id="L27" class="LineNr"> 27 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L28" class="LineNr"> 28 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L29" class="LineNr"> 29 </span>  ]
 <span id="L30" class="LineNr"> 30 </span>  <span class="Comment"># click on the code in the sandbox</span>
 <span id="L31" class="LineNr"> 31 </span>  assume-console [
-<span id="L32" class="LineNr"> 32 </span>    left-click<span class="Constant"> 4</span>,<span class="Constant"> 51</span>
+<span id="L32" class="LineNr"> 32 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 4</span>,<span class="Constant"> 51</span>
 <span id="L33" class="LineNr"> 33 </span>  ]
 <span id="L34" class="LineNr"> 34 </span>  run [
-<span id="L35" class="LineNr"> 35 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
-<span id="L36" class="LineNr"> 36 </span>    cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
-<span id="L37" class="LineNr"> 37 </span>    print <a href='../081print.mu.html#L4'>screen</a>, cursor
+<span id="L35" class="LineNr"> 35 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L36" class="LineNr"> 36 </span>  <span class="Conceal">¦</span> cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
+<span id="L37" class="LineNr"> 37 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, cursor
 <span id="L38" class="LineNr"> 38 </span>  ]
 <span id="L39" class="LineNr"> 39 </span>  <span class="Comment"># trace now printed and cursor shouldn't have budged</span>
 <span id="L40" class="LineNr"> 40 </span>  screen-should-contain [
-<span id="L41" class="LineNr"> 41 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L42" class="LineNr"> 42 </span>   <span class="Constant"> .␣ecipe foo [                                      ╎                                                 .</span>
-<span id="L43" class="LineNr"> 43 </span>   <span class="Constant"> .  stash [abc]                                     ╎─────────────────────────────────────────────────.</span>
-<span id="L44" class="LineNr"> 44 </span>   <span class="Constant"> .]                                                 ╎0   edit          copy            delete         .</span>
-<span id="L45" class="LineNr"> 45 </span>   <span class="Constant"> .                                                  ╎foo                                              .</span>
-<span id="L46" class="LineNr"> 46 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎abc                                              .</span>
+<span id="L41" class="LineNr"> 41 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L42" class="LineNr"> 42 </span>  <span class="Conceal">¦</span><span class="Constant"> .␣ecipe foo [                                      ╎                                                 .</span>
+<span id="L43" class="LineNr"> 43 </span>  <span class="Conceal">¦</span><span class="Constant"> .  stash [abc]                                     ╎─────────────────────────────────────────────────.</span>
+<span id="L44" class="LineNr"> 44 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎0   edit          copy            delete         .</span>
+<span id="L45" class="LineNr"> 45 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎foo                                              .</span>
+<span id="L46" class="LineNr"> 46 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎abc                                              .</span>
 <span id="L47" class="LineNr"> 47 </span>  ]
 <span id="L48" class="LineNr"> 48 </span>  screen-should-contain-in-color <span class="Constant">245/grey</span>, [
-<span id="L49" class="LineNr"> 49 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L50" class="LineNr"> 50 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L51" class="LineNr"> 51 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L52" class="LineNr"> 52 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L53" class="LineNr"> 53 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L54" class="LineNr"> 54 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎abc                                              .</span>
+<span id="L49" class="LineNr"> 49 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L50" class="LineNr"> 50 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L51" class="LineNr"> 51 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L52" class="LineNr"> 52 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L53" class="LineNr"> 53 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L54" class="LineNr"> 54 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎abc                                              .</span>
 <span id="L55" class="LineNr"> 55 </span>  ]
 <span id="L56" class="LineNr"> 56 </span>  <span class="Comment"># click again on the same region</span>
 <span id="L57" class="LineNr"> 57 </span>  assume-console [
-<span id="L58" class="LineNr"> 58 </span>    left-click<span class="Constant"> 4</span>,<span class="Constant"> 55</span>
+<span id="L58" class="LineNr"> 58 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 4</span>,<span class="Constant"> 55</span>
 <span id="L59" class="LineNr"> 59 </span>  ]
 <span id="L60" class="LineNr"> 60 </span>  run [
-<span id="L61" class="LineNr"> 61 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
-<span id="L62" class="LineNr"> 62 </span>    print <a href='../081print.mu.html#L4'>screen</a>, cursor
+<span id="L61" class="LineNr"> 61 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L62" class="LineNr"> 62 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L4'>screen</a>, cursor
 <span id="L63" class="LineNr"> 63 </span>  ]
 <span id="L64" class="LineNr"> 64 </span>  <span class="Comment"># trace hidden again</span>
 <span id="L65" class="LineNr"> 65 </span>  screen-should-contain [
-<span id="L66" class="LineNr"> 66 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L67" class="LineNr"> 67 </span>   <span class="Constant"> .␣ecipe foo [                                      ╎                                                 .</span>
-<span id="L68" class="LineNr"> 68 </span>   <span class="Constant"> .  stash [abc]                                     ╎─────────────────────────────────────────────────.</span>
-<span id="L69" class="LineNr"> 69 </span>   <span class="Constant"> .]                                                 ╎0   edit          copy            delete         .</span>
-<span id="L70" class="LineNr"> 70 </span>   <span class="Constant"> .                                                  ╎foo                                              .</span>
-<span id="L71" class="LineNr"> 71 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L72" class="LineNr"> 72 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L66" class="LineNr"> 66 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L67" class="LineNr"> 67 </span>  <span class="Conceal">¦</span><span class="Constant"> .␣ecipe foo [                                      ╎                                                 .</span>
+<span id="L68" class="LineNr"> 68 </span>  <span class="Conceal">¦</span><span class="Constant"> .  stash [abc]                                     ╎─────────────────────────────────────────────────.</span>
+<span id="L69" class="LineNr"> 69 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎0   edit          copy            delete         .</span>
+<span id="L70" class="LineNr"> 70 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎foo                                              .</span>
+<span id="L71" class="LineNr"> 71 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L72" class="LineNr"> 72 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L73" class="LineNr"> 73 </span>  ]
 <span id="L74" class="LineNr"> 74 </span>]
 <span id="L75" class="LineNr"> 75 </span>
@@ -140,48 +141,48 @@ if ('onhashchange' in window) {
 <span id="L79" class="LineNr"> 79 </span>  assume-screen <span class="Constant">100/width</span>, <span class="Constant">10/height</span>
 <span id="L80" class="LineNr"> 80 </span>  <span class="Comment"># basic recipe</span>
 <span id="L81" class="LineNr"> 81 </span>  assume-resources [
-<span id="L82" class="LineNr"> 82 </span>    <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
-<span id="L83" class="LineNr"> 83 </span>      <span class="Constant">|recipe</span> foo <span class="Constant">[|</span>
-<span id="L84" class="LineNr"> 84 </span><span class="Constant">      |  stash [abc]</span>|
-<span id="L85" class="LineNr"> 85 </span>      <span class="Constant">|</span>  <span class="muControl">reply</span> 4|
-<span id="L86" class="LineNr"> 86 </span><span class="Constant">      |]|</span>
-<span id="L87" class="LineNr"> 87 </span>    ]
+<span id="L82" class="LineNr"> 82 </span>  <span class="Conceal">¦</span> <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
+<span id="L83" class="LineNr"> 83 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Constant">|recipe</span> foo <span class="Constant">[|</span>
+<span id="L84" class="LineNr"> 84 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  stash [abc]</span>|
+<span id="L85" class="LineNr"> 85 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Constant">|</span>  <span class="muControl">reply</span> 4|
+<span id="L86" class="LineNr"> 86 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |]|</span>
+<span id="L87" class="LineNr"> 87 </span>  <span class="Conceal">¦</span> ]
 <span id="L88" class="LineNr"> 88 </span>  ]
 <span id="L89" class="LineNr"> 89 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[foo]</span>
 <span id="L90" class="LineNr"> 90 </span>  <span class="Comment"># run it</span>
 <span id="L91" class="LineNr"> 91 </span>  assume-console [
-<span id="L92" class="LineNr"> 92 </span>    press F4
+<span id="L92" class="LineNr"> 92 </span>  <span class="Conceal">¦</span> press F4
 <span id="L93" class="LineNr"> 93 </span>  ]
 <span id="L94" class="LineNr"> 94 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L95" class="LineNr"> 95 </span>  screen-should-contain [
-<span id="L96" class="LineNr"> 96 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L97" class="LineNr"> 97 </span>   <span class="Constant"> .recipe foo [                                      ╎                                                 .</span>
-<span id="L98" class="LineNr"> 98 </span>   <span class="Constant"> .  stash [abc]                                     ╎─────────────────────────────────────────────────.</span>
-<span id="L99" class="LineNr"> 99 </span>   <span class="Constant"> .  reply 4                                         ╎0   edit          copy            delete         .</span>
-<span id="L100" class="LineNr">100 </span>   <span class="Constant"> .]                                                 ╎foo                                              .</span>
-<span id="L101" class="LineNr">101 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
-<span id="L102" class="LineNr">102 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L103" class="LineNr">103 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L96" class="LineNr"> 96 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L97" class="LineNr"> 97 </span>  <span class="Conceal">¦</span><span class="Constant"> .recipe foo [                                      ╎                                                 .</span>
+<span id="L98" class="LineNr"> 98 </span>  <span class="Conceal">¦</span><span class="Constant"> .  stash [abc]                                     ╎─────────────────────────────────────────────────.</span>
+<span id="L99" class="LineNr"> 99 </span>  <span class="Conceal">¦</span><span class="Constant"> .  reply 4                                         ╎0   edit          copy            delete         .</span>
+<span id="L100" class="LineNr">100 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎foo                                              .</span>
+<span id="L101" class="LineNr">101 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L102" class="LineNr">102 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L103" class="LineNr">103 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L104" class="LineNr">104 </span>  ]
 <span id="L105" class="LineNr">105 </span>  <span class="Comment"># click on the code in the sandbox</span>
 <span id="L106" class="LineNr">106 </span>  assume-console [
-<span id="L107" class="LineNr">107 </span>    left-click<span class="Constant"> 4</span>,<span class="Constant"> 51</span>
+<span id="L107" class="LineNr">107 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 4</span>,<span class="Constant"> 51</span>
 <span id="L108" class="LineNr">108 </span>  ]
 <span id="L109" class="LineNr">109 </span>  run [
-<span id="L110" class="LineNr">110 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L110" class="LineNr">110 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L111" class="LineNr">111 </span>  ]
 <span id="L112" class="LineNr">112 </span>  <span class="Comment"># trace now printed above result</span>
 <span id="L113" class="LineNr">113 </span>  screen-should-contain [
-<span id="L114" class="LineNr">114 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L115" class="LineNr">115 </span>   <span class="Constant"> .recipe foo [                                      ╎                                                 .</span>
-<span id="L116" class="LineNr">116 </span>   <span class="Constant"> .  stash [abc]                                     ╎─────────────────────────────────────────────────.</span>
-<span id="L117" class="LineNr">117 </span>   <span class="Constant"> .  reply 4                                         ╎0   edit          copy            delete         .</span>
-<span id="L118" class="LineNr">118 </span>   <span class="Constant"> .]                                                 ╎foo                                              .</span>
-<span id="L119" class="LineNr">119 </span>   <span class="Constant"> .                                                  ╎abc                                              .</span>
-<span id="L120" class="LineNr">120 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎8 instructions run                               .</span>
-<span id="L121" class="LineNr">121 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
-<span id="L122" class="LineNr">122 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L123" class="LineNr">123 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L114" class="LineNr">114 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L115" class="LineNr">115 </span>  <span class="Conceal">¦</span><span class="Constant"> .recipe foo [                                      ╎                                                 .</span>
+<span id="L116" class="LineNr">116 </span>  <span class="Conceal">¦</span><span class="Constant"> .  stash [abc]                                     ╎─────────────────────────────────────────────────.</span>
+<span id="L117" class="LineNr">117 </span>  <span class="Conceal">¦</span><span class="Constant"> .  reply 4                                         ╎0   edit          copy            delete         .</span>
+<span id="L118" class="LineNr">118 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎foo                                              .</span>
+<span id="L119" class="LineNr">119 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎abc                                              .</span>
+<span id="L120" class="LineNr">120 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎8 instructions run                               .</span>
+<span id="L121" class="LineNr">121 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L122" class="LineNr">122 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L123" class="LineNr">123 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L124" class="LineNr">124 </span>  ]
 <span id="L125" class="LineNr">125 </span>]
 <span id="L126" class="LineNr">126 </span>
@@ -194,33 +195,33 @@ if ('onhashchange' in window) {
 <span id="L133" class="LineNr">133 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[stash 123456789]</span>
 <span id="L134" class="LineNr">134 </span>  <span class="Comment"># create and expand the trace</span>
 <span id="L135" class="LineNr">135 </span>  assume-console [
-<span id="L136" class="LineNr">136 </span>    press F4
-<span id="L137" class="LineNr">137 </span>    left-click<span class="Constant"> 4</span>,<span class="Constant"> 51</span>
+<span id="L136" class="LineNr">136 </span>  <span class="Conceal">¦</span> press F4
+<span id="L137" class="LineNr">137 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 4</span>,<span class="Constant"> 51</span>
 <span id="L138" class="LineNr">138 </span>  ]
 <span id="L139" class="LineNr">139 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L140" class="LineNr">140 </span>  screen-should-contain [
-<span id="L141" class="LineNr">141 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L142" class="LineNr">142 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L143" class="LineNr">143 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L144" class="LineNr">144 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L145" class="LineNr">145 </span>   <span class="Constant"> .                                                  ╎stash 123456789                                  .</span>
-<span id="L146" class="LineNr">146 </span>   <span class="Constant"> .                                                  ╎123456789                                        .</span>
+<span id="L141" class="LineNr">141 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L142" class="LineNr">142 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L143" class="LineNr">143 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L144" class="LineNr">144 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L145" class="LineNr">145 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎stash 123456789                                  .</span>
+<span id="L146" class="LineNr">146 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎123456789                                        .</span>
 <span id="L147" class="LineNr">147 </span>  ]
 <span id="L148" class="LineNr">148 </span>  <span class="Comment"># click on the stash under the edit-button region (or any of the other buttons, really)</span>
 <span id="L149" class="LineNr">149 </span>  assume-console [
-<span id="L150" class="LineNr">150 </span>    left-click<span class="Constant"> 5</span>,<span class="Constant"> 57</span>
+<span id="L150" class="LineNr">150 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 5</span>,<span class="Constant"> 57</span>
 <span id="L151" class="LineNr">151 </span>  ]
 <span id="L152" class="LineNr">152 </span>  run [
-<span id="L153" class="LineNr">153 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L153" class="LineNr">153 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L154" class="LineNr">154 </span>  ]
 <span id="L155" class="LineNr">155 </span>  <span class="Comment"># no change; doesn't die</span>
 <span id="L156" class="LineNr">156 </span>  screen-should-contain [
-<span id="L157" class="LineNr">157 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L158" class="LineNr">158 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L159" class="LineNr">159 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L160" class="LineNr">160 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L161" class="LineNr">161 </span>   <span class="Constant"> .                                                  ╎stash 123456789                                  .</span>
-<span id="L162" class="LineNr">162 </span>   <span class="Constant"> .                                                  ╎123456789                                        .</span>
+<span id="L157" class="LineNr">157 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L158" class="LineNr">158 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L159" class="LineNr">159 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L160" class="LineNr">160 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L161" class="LineNr">161 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎stash 123456789                                  .</span>
+<span id="L162" class="LineNr">162 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎123456789                                        .</span>
 <span id="L163" class="LineNr">163 </span>  ]
 <span id="L164" class="LineNr">164 </span>]
 <span id="L165" class="LineNr">165 </span>
@@ -244,29 +245,29 @@ if ('onhashchange' in window) {
 <span id="L183" class="LineNr">183 </span><span class="muRecipe">after</span> <span class="Constant"><a href='004-programming-environment.mu.html#L80'>&lt;global-touch&gt;</a></span> [
 <span id="L184" class="LineNr">184 </span>  <span class="Comment"># check if it's inside the code of any sandbox</span>
 <span id="L185" class="LineNr">185 </span>  <span class="Delimiter">{</span>
-<span id="L186" class="LineNr">186 </span>    sandbox-left-margin:num <span class="Special">&lt;-</span> get *current-sandbox, <span class="Constant">left:offset</span>
-<span id="L187" class="LineNr">187 </span>    click-column:num <span class="Special">&lt;-</span> get t, <span class="Constant">column:offset</span>
-<span id="L188" class="LineNr">188 </span>    on-sandbox-side?:bool <span class="Special">&lt;-</span> greater-or-equal click-column, sandbox-left-margin
-<span id="L189" class="LineNr">189 </span>    <span class="muControl">break-unless</span> on-sandbox-side?
-<span id="L190" class="LineNr">190 </span>    first-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *env, <span class="Constant">sandbox:offset</span>
-<span id="L191" class="LineNr">191 </span>    <span class="muControl">break-unless</span> first-sandbox
-<span id="L192" class="LineNr">192 </span>    first-sandbox-begins:num <span class="Special">&lt;-</span> get *first-sandbox, <span class="Constant">starting-row-on-screen:offset</span>
-<span id="L193" class="LineNr">193 </span>    click-row:num <span class="Special">&lt;-</span> get t, <span class="Constant">row:offset</span>
-<span id="L194" class="LineNr">194 </span>    below-sandbox-editor?:bool <span class="Special">&lt;-</span> greater-or-equal click-row, first-sandbox-begins
-<span id="L195" class="LineNr">195 </span>    <span class="muControl">break-unless</span> below-sandbox-editor?
-<span id="L196" class="LineNr">196 </span>    <span class="Comment"># identify the sandbox whose code is being clicked on</span>
-<span id="L197" class="LineNr">197 </span>    sandbox:&amp;:sandbox <span class="Special">&lt;-</span> <a href='010-sandbox-trace.mu.html#L212'>find-click-in-sandbox-code</a> env, click-row
-<span id="L198" class="LineNr">198 </span>    <span class="muControl">break-unless</span> sandbox
-<span id="L199" class="LineNr">199 </span>    <span class="Comment"># toggle its display-trace? property</span>
-<span id="L200" class="LineNr">200 </span>    x:bool <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">display-trace?:offset</span>
-<span id="L201" class="LineNr">201 </span>    x <span class="Special">&lt;-</span> not x
-<span id="L202" class="LineNr">202 </span>    *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">display-trace?:offset</span>, x
-<span id="L203" class="LineNr">203 </span>    <a href='../081print.mu.html#L623'>hide-screen</a> <a href='../081print.mu.html#L4'>screen</a>
-<span id="L204" class="LineNr">204 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> render-sandbox-side <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
-<span id="L205" class="LineNr">205 </span>    <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L511'>update-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, recipes, current-sandbox, sandbox-in-focus?, env
-<span id="L206" class="LineNr">206 </span>    <span class="Comment"># no change in cursor</span>
-<span id="L207" class="LineNr">207 </span>    <a href='../081print.mu.html#L631'>show-screen</a> <a href='../081print.mu.html#L4'>screen</a>
-<span id="L208" class="LineNr">208 </span>    <span class="muControl">loop</span> <span class="Constant">+next-event</span>
+<span id="L186" class="LineNr">186 </span>  <span class="Conceal">¦</span> sandbox-left-margin:num <span class="Special">&lt;-</span> get *current-sandbox, <span class="Constant">left:offset</span>
+<span id="L187" class="LineNr">187 </span>  <span class="Conceal">¦</span> click-column:num <span class="Special">&lt;-</span> get t, <span class="Constant">column:offset</span>
+<span id="L188" class="LineNr">188 </span>  <span class="Conceal">¦</span> on-sandbox-side?:bool <span class="Special">&lt;-</span> greater-or-equal click-column, sandbox-left-margin
+<span id="L189" class="LineNr">189 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> on-sandbox-side?
+<span id="L190" class="LineNr">190 </span>  <span class="Conceal">¦</span> first-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *env, <span class="Constant">sandbox:offset</span>
+<span id="L191" class="LineNr">191 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> first-sandbox
+<span id="L192" class="LineNr">192 </span>  <span class="Conceal">¦</span> first-sandbox-begins:num <span class="Special">&lt;-</span> get *first-sandbox, <span class="Constant">starting-row-on-screen:offset</span>
+<span id="L193" class="LineNr">193 </span>  <span class="Conceal">¦</span> click-row:num <span class="Special">&lt;-</span> get t, <span class="Constant">row:offset</span>
+<span id="L194" class="LineNr">194 </span>  <span class="Conceal">¦</span> below-sandbox-editor?:bool <span class="Special">&lt;-</span> greater-or-equal click-row, first-sandbox-begins
+<span id="L195" class="LineNr">195 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> below-sandbox-editor?
+<span id="L196" class="LineNr">196 </span>  <span class="Conceal">¦</span> <span class="Comment"># identify the sandbox whose code is being clicked on</span>
+<span id="L197" class="LineNr">197 </span>  <span class="Conceal">¦</span> sandbox:&amp;:sandbox <span class="Special">&lt;-</span> <a href='010-sandbox-trace.mu.html#L212'>find-click-in-sandbox-code</a> env, click-row
+<span id="L198" class="LineNr">198 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> sandbox
+<span id="L199" class="LineNr">199 </span>  <span class="Conceal">¦</span> <span class="Comment"># toggle its display-trace? property</span>
+<span id="L200" class="LineNr">200 </span>  <span class="Conceal">¦</span> x:bool <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">display-trace?:offset</span>
+<span id="L201" class="LineNr">201 </span>  <span class="Conceal">¦</span> x <span class="Special">&lt;-</span> not x
+<span id="L202" class="LineNr">202 </span>  <span class="Conceal">¦</span> *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">display-trace?:offset</span>, x
+<span id="L203" class="LineNr">203 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L623'>hide-screen</a> <a href='../081print.mu.html#L4'>screen</a>
+<span id="L204" class="LineNr">204 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> render-sandbox-side <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
+<span id="L205" class="LineNr">205 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L511'>update-cursor</a> <a href='../081print.mu.html#L4'>screen</a>, recipes, current-sandbox, sandbox-in-focus?, env
+<span id="L206" class="LineNr">206 </span>  <span class="Conceal">¦</span> <span class="Comment"># no change in cursor</span>
+<span id="L207" class="LineNr">207 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L631'>show-screen</a> <a href='../081print.mu.html#L4'>screen</a>
+<span id="L208" class="LineNr">208 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-event</span>
 <span id="L209" class="LineNr">209 </span>  <span class="Delimiter">}</span>
 <span id="L210" class="LineNr">210 </span>]
 <span id="L211" class="LineNr">211 </span>
@@ -280,13 +281,13 @@ if ('onhashchange' in window) {
 <span id="L219" class="LineNr">219 </span>  assert clicked-on-sandboxes?, <span class="Constant">[extract-sandbox called on click to sandbox editor]</span>
 <span id="L220" class="LineNr">220 </span>  <span class="Comment"># while click-row &lt; sandbox.next-sandbox.starting-row-on-screen</span>
 <span id="L221" class="LineNr">221 </span>  <span class="Delimiter">{</span>
-<span id="L222" class="LineNr">222 </span>    next-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">next-sandbox:offset</span>
-<span id="L223" class="LineNr">223 </span>    <span class="muControl">break-unless</span> next-sandbox
-<span id="L224" class="LineNr">224 </span>    next-start:num <span class="Special">&lt;-</span> get *next-sandbox, <span class="Constant">starting-row-on-screen:offset</span>
-<span id="L225" class="LineNr">225 </span>    found?:bool <span class="Special">&lt;-</span> lesser-than click-row, next-start
-<span id="L226" class="LineNr">226 </span>    <span class="muControl">break-if</span> found?
-<span id="L227" class="LineNr">227 </span>    sandbox <span class="Special">&lt;-</span> copy next-sandbox
-<span id="L228" class="LineNr">228 </span>    <span class="muControl">loop</span>
+<span id="L222" class="LineNr">222 </span>  <span class="Conceal">¦</span> next-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">next-sandbox:offset</span>
+<span id="L223" class="LineNr">223 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> next-sandbox
+<span id="L224" class="LineNr">224 </span>  <span class="Conceal">¦</span> next-start:num <span class="Special">&lt;-</span> get *next-sandbox, <span class="Constant">starting-row-on-screen:offset</span>
+<span id="L225" class="LineNr">225 </span>  <span class="Conceal">¦</span> found?:bool <span class="Special">&lt;-</span> lesser-than click-row, next-start
+<span id="L226" class="LineNr">226 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> found?
+<span id="L227" class="LineNr">227 </span>  <span class="Conceal">¦</span> sandbox <span class="Special">&lt;-</span> copy next-sandbox
+<span id="L228" class="LineNr">228 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L229" class="LineNr">229 </span>  <span class="Delimiter">}</span>
 <span id="L230" class="LineNr">230 </span>  <span class="Comment"># return sandbox if click is in its code region</span>
 <span id="L231" class="LineNr">231 </span>  code-ending-row:num <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">code-ending-row-on-screen:offset</span>
@@ -295,8 +296,8 @@ if ('onhashchange' in window) {
 <span id="L234" class="LineNr">234 </span>  click-below-menu?:bool <span class="Special">&lt;-</span> greater-than click-row, start
 <span id="L235" class="LineNr">235 </span>  click-on-sandbox-code?:bool <span class="Special">&lt;-</span> and click-above-response?, click-below-menu?
 <span id="L236" class="LineNr">236 </span>  <span class="Delimiter">{</span>
-<span id="L237" class="LineNr">237 </span>    <span class="muControl">break-if</span> click-on-sandbox-code?
-<span id="L238" class="LineNr">238 </span>    <span class="muControl">return</span> <span class="Constant">0/no-click-in-sandbox-output</span>
+<span id="L237" class="LineNr">237 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> click-on-sandbox-code?
+<span id="L238" class="LineNr">238 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">0/no-click-in-sandbox-output</span>
 <span id="L239" class="LineNr">239 </span>  <span class="Delimiter">}</span>
 <span id="L240" class="LineNr">240 </span>  <span class="muControl">return</span> sandbox
 <span id="L241" class="LineNr">241 </span>]
@@ -304,11 +305,11 @@ if ('onhashchange' in window) {
 <span id="L243" class="LineNr">243 </span><span class="Comment"># when rendering a sandbox, dump its trace before response/warning if display-trace? property is set</span>
 <span id="L244" class="LineNr">244 </span><span class="muRecipe">after</span> <span class="Constant"><a href='005-sandbox.mu.html#L283'>&lt;render-sandbox-results&gt;</a></span> [
 <span id="L245" class="LineNr">245 </span>  <span class="Delimiter">{</span>
-<span id="L246" class="LineNr">246 </span>    display-trace?:bool <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">display-trace?:offset</span>
-<span id="L247" class="LineNr">247 </span>    <span class="muControl">break-unless</span> display-trace?
-<span id="L248" class="LineNr">248 </span>    sandbox-trace:text <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">trace:offset</span>
-<span id="L249" class="LineNr">249 </span>    <span class="muControl">break-unless</span> sandbox-trace  <span class="Comment"># nothing to print; move on</span>
-<span id="L250" class="LineNr">250 </span>    row, <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L356'>render-text</a> <a href='../081print.mu.html#L4'>screen</a>, sandbox-trace, left, right, <span class="Constant">245/grey</span>, row
+<span id="L246" class="LineNr">246 </span>  <span class="Conceal">¦</span> display-trace?:bool <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">display-trace?:offset</span>
+<span id="L247" class="LineNr">247 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> display-trace?
+<span id="L248" class="LineNr">248 </span>  <span class="Conceal">¦</span> sandbox-trace:text <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">trace:offset</span>
+<span id="L249" class="LineNr">249 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> sandbox-trace  <span class="Comment"># nothing to print; move on</span>
+<span id="L250" class="LineNr">250 </span>  <span class="Conceal">¦</span> row, <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L356'>render-text</a> <a href='../081print.mu.html#L4'>screen</a>, sandbox-trace, left, right, <span class="Constant">245/grey</span>, row
 <span id="L251" class="LineNr">251 </span>  <span class="Delimiter">}</span>
 <span id="L252" class="LineNr">252 </span><span class="Constant">  <a href='010-sandbox-trace.mu.html#L252'>&lt;render-sandbox-trace-done&gt;</a></span>
 <span id="L253" class="LineNr">253 </span>]
diff --git a/html/edit/011-errors.mu.html b/html/edit/011-errors.mu.html
index c30f72a8..5a15e5ff 100644
--- a/html/edit/011-errors.mu.html
+++ b/html/edit/011-errors.mu.html
@@ -15,16 +15,17 @@ body { font-size: 12pt; font-family: monospace; color: #eeeeee; background-color
 a { text-decoration: none; }
 a:hover { text-decoration: underline; }
 * { font-size: 12pt; font-size: 1em; }
-.muData { color: #ffff00; }
-.muControl { color: #c0a020; }
+.muRecipe { color: #ff8700; }
+.muScenario { color: #00af00; }
 .Special { color: #c00000; }
+.Conceal { color: #4e4e4e; }
 .Delimiter { color: #800080; }
 .SalientComment { color: #00ffff; }
 .Constant { color: #00a0a0; }
 .LineNr { color: #444444; }
 .Comment { color: #9090ff; }
-.muRecipe { color: #ff8700; }
-.muScenario { color: #00af00; }
+.muControl { color: #c0a020; }
+.muData { color: #ffff00; }
 -->
 </style>
 
@@ -76,10 +77,10 @@ if ('onhashchange' in window) {
 <span id="L15" class="LineNr"> 15 </span>  *env <span class="Special">&lt;-</span> put *env, <span class="Constant">recipe-errors:offset</span>, recipe-errors
 <span id="L16" class="LineNr"> 16 </span>  <span class="Comment"># if recipe editor has errors, stop</span>
 <span id="L17" class="LineNr"> 17 </span>  <span class="Delimiter">{</span>
-<span id="L18" class="LineNr"> 18 </span>    <span class="muControl">break-unless</span> recipe-errors
-<span id="L19" class="LineNr"> 19 </span>    <a href='005-sandbox.mu.html#L208'>update-status</a> <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[errors found     ]</span>, <span class="Constant">1/red</span>
-<span id="L20" class="LineNr"> 20 </span>    errors-found? <span class="Special">&lt;-</span> copy <span class="Constant">1/true</span>
-<span id="L21" class="LineNr"> 21 </span>    <span class="muControl">return</span>
+<span id="L18" class="LineNr"> 18 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> recipe-errors
+<span id="L19" class="LineNr"> 19 </span>  <span class="Conceal">¦</span> <a href='005-sandbox.mu.html#L208'>update-status</a> <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[errors found     ]</span>, <span class="Constant">1/red</span>
+<span id="L20" class="LineNr"> 20 </span>  <span class="Conceal">¦</span> errors-found? <span class="Special">&lt;-</span> copy <span class="Constant">1/true</span>
+<span id="L21" class="LineNr"> 21 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
 <span id="L22" class="LineNr"> 22 </span>  <span class="Delimiter">}</span>
 <span id="L23" class="LineNr"> 23 </span>  errors-found? <span class="Special">&lt;-</span> copy <span class="Constant">0/false</span>
 <span id="L24" class="LineNr"> 24 </span>]
@@ -88,16 +89,16 @@ if ('onhashchange' in window) {
 <span id="L27" class="LineNr"> 27 </span>  trace<span class="Constant"> 11</span>, <span class="Constant">[app]</span>, <span class="Constant">[render status]</span>
 <span id="L28" class="LineNr"> 28 </span>  recipe-errors:text <span class="Special">&lt;-</span> get *env, <span class="Constant">recipe-errors:offset</span>
 <span id="L29" class="LineNr"> 29 </span>  <span class="Delimiter">{</span>
-<span id="L30" class="LineNr"> 30 </span>    <span class="muControl">break-unless</span> recipe-errors
-<span id="L31" class="LineNr"> 31 </span>    <a href='005-sandbox.mu.html#L208'>update-status</a> <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[errors found     ]</span>, <span class="Constant">1/red</span>
+<span id="L30" class="LineNr"> 30 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> recipe-errors
+<span id="L31" class="LineNr"> 31 </span>  <span class="Conceal">¦</span> <a href='005-sandbox.mu.html#L208'>update-status</a> <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[errors found     ]</span>, <span class="Constant">1/red</span>
 <span id="L32" class="LineNr"> 32 </span>  <span class="Delimiter">}</span>
 <span id="L33" class="LineNr"> 33 </span>]
 <span id="L34" class="LineNr"> 34 </span>
 <span id="L35" class="LineNr"> 35 </span><span class="muRecipe">before</span> <span class="Constant"><a href='004-programming-environment.mu.html#L488'>&lt;render-recipe-components-end&gt;</a></span> [
 <span id="L36" class="LineNr"> 36 </span>  <span class="Delimiter">{</span>
-<span id="L37" class="LineNr"> 37 </span>    recipe-errors:text <span class="Special">&lt;-</span> get *env, <span class="Constant">recipe-errors:offset</span>
-<span id="L38" class="LineNr"> 38 </span>    <span class="muControl">break-unless</span> recipe-errors
-<span id="L39" class="LineNr"> 39 </span>    row, <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L356'>render-text</a> <a href='../081print.mu.html#L4'>screen</a>, recipe-errors, left, right, <span class="Constant">1/red</span>, row
+<span id="L37" class="LineNr"> 37 </span>  <span class="Conceal">¦</span> recipe-errors:text <span class="Special">&lt;-</span> get *env, <span class="Constant">recipe-errors:offset</span>
+<span id="L38" class="LineNr"> 38 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> recipe-errors
+<span id="L39" class="LineNr"> 39 </span>  <span class="Conceal">¦</span> row, <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L356'>render-text</a> <a href='../081print.mu.html#L4'>screen</a>, recipe-errors, left, right, <span class="Constant">1/red</span>, row
 <span id="L40" class="LineNr"> 40 </span>  <span class="Delimiter">}</span>
 <span id="L41" class="LineNr"> 41 </span>]
 <span id="L42" class="LineNr"> 42 </span>
@@ -115,22 +116,22 @@ if ('onhashchange' in window) {
 <span id="L54" class="LineNr"> 54 </span>
 <span id="L55" class="LineNr"> 55 </span><span class="muRecipe">before</span> <span class="Constant"><a href='005-sandbox.mu.html#L183'>&lt;run-sandboxes-end&gt;</a></span> [
 <span id="L56" class="LineNr"> 56 </span>  <span class="Delimiter">{</span>
-<span id="L57" class="LineNr"> 57 </span>    error-index:num <span class="Special">&lt;-</span> get *env, <span class="Constant">error-index:offset</span>
-<span id="L58" class="LineNr"> 58 </span>    sandboxes-completed-successfully?:bool <span class="Special">&lt;-</span> equal error-index,<span class="Constant"> -1</span>
-<span id="L59" class="LineNr"> 59 </span>    <span class="muControl">break-if</span> sandboxes-completed-successfully?
-<span id="L60" class="LineNr"> 60 </span>    errors-found? <span class="Special">&lt;-</span> copy <span class="Constant">1/true</span>
+<span id="L57" class="LineNr"> 57 </span>  <span class="Conceal">¦</span> error-index:num <span class="Special">&lt;-</span> get *env, <span class="Constant">error-index:offset</span>
+<span id="L58" class="LineNr"> 58 </span>  <span class="Conceal">¦</span> sandboxes-completed-successfully?:bool <span class="Special">&lt;-</span> equal error-index,<span class="Constant"> -1</span>
+<span id="L59" class="LineNr"> 59 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> sandboxes-completed-successfully?
+<span id="L60" class="LineNr"> 60 </span>  <span class="Conceal">¦</span> errors-found? <span class="Special">&lt;-</span> copy <span class="Constant">1/true</span>
 <span id="L61" class="LineNr"> 61 </span>  <span class="Delimiter">}</span>
 <span id="L62" class="LineNr"> 62 </span>]
 <span id="L63" class="LineNr"> 63 </span>
 <span id="L64" class="LineNr"> 64 </span><span class="muRecipe">before</span> <span class="Constant"><a href='004-programming-environment.mu.html#L467'>&lt;render-components-end&gt;</a></span> [
 <span id="L65" class="LineNr"> 65 </span>  <span class="Delimiter">{</span>
-<span id="L66" class="LineNr"> 66 </span>    <span class="muControl">break-if</span> recipe-errors
-<span id="L67" class="LineNr"> 67 </span>    error-index:num <span class="Special">&lt;-</span> get *env, <span class="Constant">error-index:offset</span>
-<span id="L68" class="LineNr"> 68 </span>    sandboxes-completed-successfully?:bool <span class="Special">&lt;-</span> equal error-index,<span class="Constant"> -1</span>
-<span id="L69" class="LineNr"> 69 </span>    <span class="muControl">break-if</span> sandboxes-completed-successfully?
-<span id="L70" class="LineNr"> 70 </span>    error-index-text:text <span class="Special">&lt;-</span> to-text error-index
-<span id="L71" class="LineNr"> 71 </span>    status:text <span class="Special">&lt;-</span> <a href='../061text.mu.html#L506'>interpolate</a> <span class="Constant">[errors found (_)    ]</span>, error-index-text
-<span id="L72" class="LineNr"> 72 </span>    <a href='005-sandbox.mu.html#L208'>update-status</a> <a href='../081print.mu.html#L4'>screen</a>, status, <span class="Constant">1/red</span>
+<span id="L66" class="LineNr"> 66 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> recipe-errors
+<span id="L67" class="LineNr"> 67 </span>  <span class="Conceal">¦</span> error-index:num <span class="Special">&lt;-</span> get *env, <span class="Constant">error-index:offset</span>
+<span id="L68" class="LineNr"> 68 </span>  <span class="Conceal">¦</span> sandboxes-completed-successfully?:bool <span class="Special">&lt;-</span> equal error-index,<span class="Constant"> -1</span>
+<span id="L69" class="LineNr"> 69 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> sandboxes-completed-successfully?
+<span id="L70" class="LineNr"> 70 </span>  <span class="Conceal">¦</span> error-index-text:text <span class="Special">&lt;-</span> to-text error-index
+<span id="L71" class="LineNr"> 71 </span>  <span class="Conceal">¦</span> status:text <span class="Special">&lt;-</span> <a href='../061text.mu.html#L506'>interpolate</a> <span class="Constant">[errors found (_)    ]</span>, error-index-text
+<span id="L72" class="LineNr"> 72 </span>  <span class="Conceal">¦</span> <a href='005-sandbox.mu.html#L208'>update-status</a> <a href='../081print.mu.html#L4'>screen</a>, status, <span class="Constant">1/red</span>
 <span id="L73" class="LineNr"> 73 </span>  <span class="Delimiter">}</span>
 <span id="L74" class="LineNr"> 74 </span>]
 <span id="L75" class="LineNr"> 75 </span>
@@ -148,30 +149,30 @@ if ('onhashchange' in window) {
 <span id="L87" class="LineNr"> 87 </span>  *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant"><a href='../081print.mu.html#L4'>screen</a>:offset</span>, fake-screen
 <span id="L88" class="LineNr"> 88 </span>  *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">trace:offset</span>, trace
 <span id="L89" class="LineNr"> 89 </span>  <span class="Delimiter">{</span>
-<span id="L90" class="LineNr"> 90 </span>    <span class="muControl">break-if</span> errors
-<span id="L91" class="LineNr"> 91 </span>    <span class="muControl">break-if</span> completed?:bool
-<span id="L92" class="LineNr"> 92 </span>    errors <span class="Special">&lt;-</span> new <span class="Constant">[took too long!</span>
+<span id="L90" class="LineNr"> 90 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> errors
+<span id="L91" class="LineNr"> 91 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> completed?:bool
+<span id="L92" class="LineNr"> 92 </span>  <span class="Conceal">¦</span> errors <span class="Special">&lt;-</span> new <span class="Constant">[took too long!</span>
 <span id="L93" class="LineNr"> 93 </span><span class="Constant">]</span>
-<span id="L94" class="LineNr"> 94 </span>    *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">errors:offset</span>, errors
+<span id="L94" class="LineNr"> 94 </span>  <span class="Conceal">¦</span> *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">errors:offset</span>, errors
 <span id="L95" class="LineNr"> 95 </span>  <span class="Delimiter">}</span>
 <span id="L96" class="LineNr"> 96 </span>  <span class="Delimiter">{</span>
-<span id="L97" class="LineNr"> 97 </span>    <span class="muControl">break-unless</span> errors
-<span id="L98" class="LineNr"> 98 </span>    error-index:num <span class="Special">&lt;-</span> get *env, <span class="Constant">error-index:offset</span>
-<span id="L99" class="LineNr"> 99 </span>    error-not-set?:bool <span class="Special">&lt;-</span> equal error-index,<span class="Constant"> -1</span>
-<span id="L100" class="LineNr">100 </span>    <span class="muControl">break-unless</span> error-not-set?
-<span id="L101" class="LineNr">101 </span>    *env <span class="Special">&lt;-</span> put *env, <span class="Constant">error-index:offset</span>, idx
+<span id="L97" class="LineNr"> 97 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> errors
+<span id="L98" class="LineNr"> 98 </span>  <span class="Conceal">¦</span> error-index:num <span class="Special">&lt;-</span> get *env, <span class="Constant">error-index:offset</span>
+<span id="L99" class="LineNr"> 99 </span>  <span class="Conceal">¦</span> error-not-set?:bool <span class="Special">&lt;-</span> equal error-index,<span class="Constant"> -1</span>
+<span id="L100" class="LineNr">100 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> error-not-set?
+<span id="L101" class="LineNr">101 </span>  <span class="Conceal">¦</span> *env <span class="Special">&lt;-</span> put *env, <span class="Constant">error-index:offset</span>, idx
 <span id="L102" class="LineNr">102 </span>  <span class="Delimiter">}</span>
 <span id="L103" class="LineNr">103 </span>]
 <span id="L104" class="LineNr">104 </span>
 <span id="L105" class="LineNr">105 </span><span class="Comment"># make sure we render any trace</span>
 <span id="L106" class="LineNr">106 </span><span class="muRecipe">after</span> <span class="Constant"><a href='010-sandbox-trace.mu.html#L252'>&lt;render-sandbox-trace-done&gt;</a></span> [
 <span id="L107" class="LineNr">107 </span>  <span class="Delimiter">{</span>
-<span id="L108" class="LineNr">108 </span>    sandbox-errors:text <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">errors:offset</span>
-<span id="L109" class="LineNr">109 </span>    <span class="muControl">break-unless</span> sandbox-errors
-<span id="L110" class="LineNr">110 </span>    *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">response-starting-row-on-screen:offset</span>,<span class="Constant"> 0</span>  <span class="Comment"># no response</span>
-<span id="L111" class="LineNr">111 </span>    row, <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L356'>render-text</a> <a href='../081print.mu.html#L4'>screen</a>, sandbox-errors, left, right, <span class="Constant">1/red</span>, row
-<span id="L112" class="LineNr">112 </span>    <span class="Comment"># don't try to print anything more for this sandbox</span>
-<span id="L113" class="LineNr">113 </span>    <span class="muControl">jump</span> <span class="Constant">+render-sandbox-end</span>
+<span id="L108" class="LineNr">108 </span>  <span class="Conceal">¦</span> sandbox-errors:text <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">errors:offset</span>
+<span id="L109" class="LineNr">109 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> sandbox-errors
+<span id="L110" class="LineNr">110 </span>  <span class="Conceal">¦</span> *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">response-starting-row-on-screen:offset</span>,<span class="Constant"> 0</span>  <span class="Comment"># no response</span>
+<span id="L111" class="LineNr">111 </span>  <span class="Conceal">¦</span> row, <a href='../081print.mu.html#L4'>screen</a> <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L356'>render-text</a> <a href='../081print.mu.html#L4'>screen</a>, sandbox-errors, left, right, <span class="Constant">1/red</span>, row
+<span id="L112" class="LineNr">112 </span>  <span class="Conceal">¦</span> <span class="Comment"># don't try to print anything more for this sandbox</span>
+<span id="L113" class="LineNr">113 </span>  <span class="Conceal">¦</span> <span class="muControl">jump</span> <span class="Constant">+render-sandbox-end</span>
 <span id="L114" class="LineNr">114 </span>  <span class="Delimiter">}</span>
 <span id="L115" class="LineNr">115 </span>]
 <span id="L116" class="LineNr">116 </span>
@@ -180,51 +181,51 @@ if ('onhashchange' in window) {
 <span id="L119" class="LineNr">119 </span>  trace-until <span class="Constant">100/app</span>  <span class="Comment"># trace too long</span>
 <span id="L120" class="LineNr">120 </span>  assume-screen <span class="Constant">100/width</span>, <span class="Constant">15/height</span>
 <span id="L121" class="LineNr">121 </span>  assume-resources [
-<span id="L122" class="LineNr">122 </span>    <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
-<span id="L123" class="LineNr">123 </span>      <span class="Constant">|recipe</span> foo <span class="Constant">[|</span>
-<span id="L124" class="LineNr">124 </span><span class="Constant">      |  get 123:num, foo:offset|</span>
-<span id="L125" class="LineNr">125 </span><span class="Constant">      |]</span>|
-<span id="L126" class="LineNr">126 </span>    ]
+<span id="L122" class="LineNr">122 </span>  <span class="Conceal">¦</span> <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
+<span id="L123" class="LineNr">123 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Constant">|recipe</span> foo <span class="Constant">[|</span>
+<span id="L124" class="LineNr">124 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  get 123:num, foo:offset|</span>
+<span id="L125" class="LineNr">125 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |]</span>|
+<span id="L126" class="LineNr">126 </span>  <span class="Conceal">¦</span> ]
 <span id="L127" class="LineNr">127 </span>  ]
 <span id="L128" class="LineNr">128 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[foo]</span>
 <span id="L129" class="LineNr">129 </span>  <a href='004-programming-environment.mu.html#L445'>render-all</a> <a href='../081print.mu.html#L4'>screen</a>, env, <a href='001-editor.mu.html#L123'>render</a>
 <span id="L130" class="LineNr">130 </span>  screen-should-contain [
-<span id="L131" class="LineNr">131 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L132" class="LineNr">132 </span>   <span class="Constant"> .recipe foo [                                      ╎foo                                              .</span>
-<span id="L133" class="LineNr">133 </span>   <span class="Constant"> .  get 123:num, foo:offset                         ╎─────────────────────────────────────────────────.</span>
-<span id="L134" class="LineNr">134 </span>   <span class="Constant"> .]                                                 ╎                                                 .</span>
-<span id="L135" class="LineNr">135 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L136" class="LineNr">136 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
-<span id="L137" class="LineNr">137 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L131" class="LineNr">131 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L132" class="LineNr">132 </span>  <span class="Conceal">¦</span><span class="Constant"> .recipe foo [                                      ╎foo                                              .</span>
+<span id="L133" class="LineNr">133 </span>  <span class="Conceal">¦</span><span class="Constant"> .  get 123:num, foo:offset                         ╎─────────────────────────────────────────────────.</span>
+<span id="L134" class="LineNr">134 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎                                                 .</span>
+<span id="L135" class="LineNr">135 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L136" class="LineNr">136 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
+<span id="L137" class="LineNr">137 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L138" class="LineNr">138 </span>  ]
 <span id="L139" class="LineNr">139 </span>  assume-console [
-<span id="L140" class="LineNr">140 </span>    press F4
+<span id="L140" class="LineNr">140 </span>  <span class="Conceal">¦</span> press F4
 <span id="L141" class="LineNr">141 </span>  ]
 <span id="L142" class="LineNr">142 </span>  run [
-<span id="L143" class="LineNr">143 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L143" class="LineNr">143 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L144" class="LineNr">144 </span>  ]
 <span id="L145" class="LineNr">145 </span>  screen-should-contain [
-<span id="L146" class="LineNr">146 </span>   <span class="Constant"> .  errors found                                                                   run (F4)           .</span>
-<span id="L147" class="LineNr">147 </span>   <span class="Constant"> .recipe foo [                                      ╎foo                                              .</span>
-<span id="L148" class="LineNr">148 </span>   <span class="Constant"> .  get 123:num, foo:offset                         ╎─────────────────────────────────────────────────.</span>
-<span id="L149" class="LineNr">149 </span>   <span class="Constant"> .]                                                 ╎                                                 .</span>
-<span id="L150" class="LineNr">150 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L151" class="LineNr">151 </span>   <span class="Constant"> .foo: unknown element 'foo' in container 'number'  ╎                                                 .</span>
-<span id="L152" class="LineNr">152 </span>   <span class="Constant"> .foo: first ingredient of 'get' should be a contai↩╎                                                 .</span>
-<span id="L153" class="LineNr">153 </span>   <span class="Constant"> .ner, but got '123:num'                            ╎                                                 .</span>
-<span id="L154" class="LineNr">154 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
-<span id="L155" class="LineNr">155 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L146" class="LineNr">146 </span>  <span class="Conceal">¦</span><span class="Constant"> .  errors found                                                                   run (F4)           .</span>
+<span id="L147" class="LineNr">147 </span>  <span class="Conceal">¦</span><span class="Constant"> .recipe foo [                                      ╎foo                                              .</span>
+<span id="L148" class="LineNr">148 </span>  <span class="Conceal">¦</span><span class="Constant"> .  get 123:num, foo:offset                         ╎─────────────────────────────────────────────────.</span>
+<span id="L149" class="LineNr">149 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎                                                 .</span>
+<span id="L150" class="LineNr">150 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L151" class="LineNr">151 </span>  <span class="Conceal">¦</span><span class="Constant"> .foo: unknown element 'foo' in container 'number'  ╎                                                 .</span>
+<span id="L152" class="LineNr">152 </span>  <span class="Conceal">¦</span><span class="Constant"> .foo: first ingredient of 'get' should be a contai↩╎                                                 .</span>
+<span id="L153" class="LineNr">153 </span>  <span class="Conceal">¦</span><span class="Constant"> .ner, but got '123:num'                            ╎                                                 .</span>
+<span id="L154" class="LineNr">154 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
+<span id="L155" class="LineNr">155 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L156" class="LineNr">156 </span>  ]
 <span id="L157" class="LineNr">157 </span>  screen-should-contain-in-color <span class="Constant">1/red</span>, [
-<span id="L158" class="LineNr">158 </span>   <span class="Constant"> .  errors found                                                                                      .</span>
-<span id="L159" class="LineNr">159 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L160" class="LineNr">160 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L161" class="LineNr">161 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L162" class="LineNr">162 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L163" class="LineNr">163 </span>   <span class="Constant"> .foo: unknown element 'foo' in container 'number'                                                    .</span>
-<span id="L164" class="LineNr">164 </span>   <span class="Constant"> .foo: first ingredient of 'get' should be a contai                                                   .</span>
-<span id="L165" class="LineNr">165 </span>   <span class="Constant"> .ner, but got '123:num'                                                                              .</span>
-<span id="L166" class="LineNr">166 </span>   <span class="Constant"> .                                                                                                    .</span>
+<span id="L158" class="LineNr">158 </span>  <span class="Conceal">¦</span><span class="Constant"> .  errors found                                                                                      .</span>
+<span id="L159" class="LineNr">159 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L160" class="LineNr">160 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L161" class="LineNr">161 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L162" class="LineNr">162 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L163" class="LineNr">163 </span>  <span class="Conceal">¦</span><span class="Constant"> .foo: unknown element 'foo' in container 'number'                                                    .</span>
+<span id="L164" class="LineNr">164 </span>  <span class="Conceal">¦</span><span class="Constant"> .foo: first ingredient of 'get' should be a contai                                                   .</span>
+<span id="L165" class="LineNr">165 </span>  <span class="Conceal">¦</span><span class="Constant"> .ner, but got '123:num'                                                                              .</span>
+<span id="L166" class="LineNr">166 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
 <span id="L167" class="LineNr">167 </span>  ]
 <span id="L168" class="LineNr">168 </span>]
 <span id="L169" class="LineNr">169 </span>
@@ -236,20 +237,20 @@ if ('onhashchange' in window) {
 <span id="L175" class="LineNr">175 </span>  ]
 <span id="L176" class="LineNr">176 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[]</span>
 <span id="L177" class="LineNr">177 </span>  assume-console [
-<span id="L178" class="LineNr">178 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 80</span>
-<span id="L179" class="LineNr">179 </span>    <span class="Comment"># create invalid sandbox 1</span>
-<span id="L180" class="LineNr">180 </span>    type <span class="Constant">[get foo, x:offset]</span>
-<span id="L181" class="LineNr">181 </span>    press F4
-<span id="L182" class="LineNr">182 </span>    <span class="Comment"># create invalid sandbox 0</span>
-<span id="L183" class="LineNr">183 </span>    type <span class="Constant">[get foo, x:offset]</span>
-<span id="L184" class="LineNr">184 </span>    press F4
+<span id="L178" class="LineNr">178 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 80</span>
+<span id="L179" class="LineNr">179 </span>  <span class="Conceal">¦</span> <span class="Comment"># create invalid sandbox 1</span>
+<span id="L180" class="LineNr">180 </span>  <span class="Conceal">¦</span> type <span class="Constant">[get foo, x:offset]</span>
+<span id="L181" class="LineNr">181 </span>  <span class="Conceal">¦</span> press F4
+<span id="L182" class="LineNr">182 </span>  <span class="Conceal">¦</span> <span class="Comment"># create invalid sandbox 0</span>
+<span id="L183" class="LineNr">183 </span>  <span class="Conceal">¦</span> type <span class="Constant">[get foo, x:offset]</span>
+<span id="L184" class="LineNr">184 </span>  <span class="Conceal">¦</span> press F4
 <span id="L185" class="LineNr">185 </span>  ]
 <span id="L186" class="LineNr">186 </span>  run [
-<span id="L187" class="LineNr">187 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L187" class="LineNr">187 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L188" class="LineNr">188 </span>  ]
 <span id="L189" class="LineNr">189 </span>  <span class="Comment"># status line shows that error is in first sandbox</span>
 <span id="L190" class="LineNr">190 </span>  screen-should-contain [
-<span id="L191" class="LineNr">191 </span>   <span class="Constant"> .  errors found (0)                                                               run (F4)           .</span>
+<span id="L191" class="LineNr">191 </span>  <span class="Conceal">¦</span><span class="Constant"> .  errors found (0)                                                               run (F4)           .</span>
 <span id="L192" class="LineNr">192 </span>  ]
 <span id="L193" class="LineNr">193 </span>]
 <span id="L194" class="LineNr">194 </span>
@@ -261,23 +262,23 @@ if ('onhashchange' in window) {
 <span id="L200" class="LineNr">200 </span>  ]
 <span id="L201" class="LineNr">201 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[]</span>
 <span id="L202" class="LineNr">202 </span>  assume-console [
-<span id="L203" class="LineNr">203 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 80</span>
-<span id="L204" class="LineNr">204 </span>    <span class="Comment"># create invalid sandbox 2</span>
-<span id="L205" class="LineNr">205 </span>    type <span class="Constant">[get foo, x:offset]</span>
-<span id="L206" class="LineNr">206 </span>    press F4
-<span id="L207" class="LineNr">207 </span>    <span class="Comment"># create invalid sandbox 1</span>
-<span id="L208" class="LineNr">208 </span>    type <span class="Constant">[get foo, x:offset]</span>
-<span id="L209" class="LineNr">209 </span>    press F4
-<span id="L210" class="LineNr">210 </span>    <span class="Comment"># create valid sandbox 0</span>
-<span id="L211" class="LineNr">211 </span>    type <span class="Constant">[add 2, 2]</span>
-<span id="L212" class="LineNr">212 </span>    press F4
+<span id="L203" class="LineNr">203 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 80</span>
+<span id="L204" class="LineNr">204 </span>  <span class="Conceal">¦</span> <span class="Comment"># create invalid sandbox 2</span>
+<span id="L205" class="LineNr">205 </span>  <span class="Conceal">¦</span> type <span class="Constant">[get foo, x:offset]</span>
+<span id="L206" class="LineNr">206 </span>  <span class="Conceal">¦</span> press F4
+<span id="L207" class="LineNr">207 </span>  <span class="Conceal">¦</span> <span class="Comment"># create invalid sandbox 1</span>
+<span id="L208" class="LineNr">208 </span>  <span class="Conceal">¦</span> type <span class="Constant">[get foo, x:offset]</span>
+<span id="L209" class="LineNr">209 </span>  <span class="Conceal">¦</span> press F4
+<span id="L210" class="LineNr">210 </span>  <span class="Conceal">¦</span> <span class="Comment"># create valid sandbox 0</span>
+<span id="L211" class="LineNr">211 </span>  <span class="Conceal">¦</span> type <span class="Constant">[add 2, 2]</span>
+<span id="L212" class="LineNr">212 </span>  <span class="Conceal">¦</span> press F4
 <span id="L213" class="LineNr">213 </span>  ]
 <span id="L214" class="LineNr">214 </span>  run [
-<span id="L215" class="LineNr">215 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L215" class="LineNr">215 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L216" class="LineNr">216 </span>  ]
 <span id="L217" class="LineNr">217 </span>  <span class="Comment"># status line shows that error is in second sandbox</span>
 <span id="L218" class="LineNr">218 </span>  screen-should-contain [
-<span id="L219" class="LineNr">219 </span>   <span class="Constant"> .  errors found (1)                                                               run (F4)           .</span>
+<span id="L219" class="LineNr">219 </span>  <span class="Conceal">¦</span><span class="Constant"> .  errors found (1)                                                               run (F4)           .</span>
 <span id="L220" class="LineNr">220 </span>  ]
 <span id="L221" class="LineNr">221 </span>]
 <span id="L222" class="LineNr">222 </span>
@@ -289,28 +290,28 @@ if ('onhashchange' in window) {
 <span id="L228" class="LineNr">228 </span>  ]
 <span id="L229" class="LineNr">229 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[get foo, x:offset]</span>  <span class="Comment"># invalid</span>
 <span id="L230" class="LineNr">230 </span>  assume-console [
-<span id="L231" class="LineNr">231 </span>    press F4  <span class="Comment"># generate error</span>
+<span id="L231" class="LineNr">231 </span>  <span class="Conceal">¦</span> press F4  <span class="Comment"># generate error</span>
 <span id="L232" class="LineNr">232 </span>  ]
 <span id="L233" class="LineNr">233 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L234" class="LineNr">234 </span>  assume-console [
-<span id="L235" class="LineNr">235 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 58</span>
-<span id="L236" class="LineNr">236 </span>    press ctrl-k
-<span id="L237" class="LineNr">237 </span>    type <span class="Constant">[add 2, 2]</span>  <span class="Comment"># valid code</span>
-<span id="L238" class="LineNr">238 </span>    press F4  <span class="Comment"># update sandbox</span>
+<span id="L235" class="LineNr">235 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 58</span>
+<span id="L236" class="LineNr">236 </span>  <span class="Conceal">¦</span> press ctrl-k
+<span id="L237" class="LineNr">237 </span>  <span class="Conceal">¦</span> type <span class="Constant">[add 2, 2]</span>  <span class="Comment"># valid code</span>
+<span id="L238" class="LineNr">238 </span>  <span class="Conceal">¦</span> press F4  <span class="Comment"># update sandbox</span>
 <span id="L239" class="LineNr">239 </span>  ]
 <span id="L240" class="LineNr">240 </span>  run [
-<span id="L241" class="LineNr">241 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L241" class="LineNr">241 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L242" class="LineNr">242 </span>  ]
 <span id="L243" class="LineNr">243 </span>  <span class="Comment"># error should disappear</span>
 <span id="L244" class="LineNr">244 </span>  screen-should-contain [
-<span id="L245" class="LineNr">245 </span>   <span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L246" class="LineNr">246 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L247" class="LineNr">247 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L248" class="LineNr">248 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L249" class="LineNr">249 </span>   <span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
-<span id="L250" class="LineNr">250 </span>   <span class="Constant"> .                                                  ╎4                                                .</span>
-<span id="L251" class="LineNr">251 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L252" class="LineNr">252 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L245" class="LineNr">245 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L246" class="LineNr">246 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L247" class="LineNr">247 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L248" class="LineNr">248 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L249" class="LineNr">249 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎add 2, 2                                         .</span>
+<span id="L250" class="LineNr">250 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎4                                                .</span>
+<span id="L251" class="LineNr">251 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L252" class="LineNr">252 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L253" class="LineNr">253 </span>  ]
 <span id="L254" class="LineNr">254 </span>]
 <span id="L255" class="LineNr">255 </span>
@@ -320,51 +321,51 @@ if ('onhashchange' in window) {
 <span id="L259" class="LineNr">259 </span>  assume-screen <span class="Constant">100/width</span>, <span class="Constant">15/height</span>
 <span id="L260" class="LineNr">260 </span>  <span class="Comment"># define a shape-shifting recipe with an error</span>
 <span id="L261" class="LineNr">261 </span>  assume-resources [
-<span id="L262" class="LineNr">262 </span>    <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
-<span id="L263" class="LineNr">263 </span>      <span class="Constant">|recipe</span> foo x:_elem<span class="muRecipe"> -&gt; </span>z:_elem <span class="Constant">[|</span>
-<span id="L264" class="LineNr">264 </span><span class="Constant">      |  local-scope|</span>
-<span id="L265" class="LineNr">265 </span><span class="Constant">      |  load-ingredients|</span>
-<span id="L266" class="LineNr">266 </span><span class="Constant">      |  y:&amp;:num &lt;- copy 0|</span>
-<span id="L267" class="LineNr">267 </span><span class="Constant">      |  z &lt;- add x, y|</span>
-<span id="L268" class="LineNr">268 </span><span class="Constant">      |]</span>|
-<span id="L269" class="LineNr">269 </span>    ]
+<span id="L262" class="LineNr">262 </span>  <span class="Conceal">¦</span> <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
+<span id="L263" class="LineNr">263 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Constant">|recipe</span> foo x:_elem<span class="muRecipe"> -&gt; </span>z:_elem <span class="Constant">[|</span>
+<span id="L264" class="LineNr">264 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  local-scope|</span>
+<span id="L265" class="LineNr">265 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  load-ingredients|</span>
+<span id="L266" class="LineNr">266 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  y:&amp;:num &lt;- copy 0|</span>
+<span id="L267" class="LineNr">267 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  z &lt;- add x, y|</span>
+<span id="L268" class="LineNr">268 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |]</span>|
+<span id="L269" class="LineNr">269 </span>  <span class="Conceal">¦</span> ]
 <span id="L270" class="LineNr">270 </span>  ]
 <span id="L271" class="LineNr">271 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[foo 2]</span>
 <span id="L272" class="LineNr">272 </span>  assume-console [
-<span id="L273" class="LineNr">273 </span>    press F4
+<span id="L273" class="LineNr">273 </span>  <span class="Conceal">¦</span> press F4
 <span id="L274" class="LineNr">274 </span>  ]
 <span id="L275" class="LineNr">275 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L276" class="LineNr">276 </span>  screen-should-contain [
-<span id="L277" class="LineNr">277 </span>   <span class="Constant"> .  errors found (0)                                                               run (F4)           .</span>
-<span id="L278" class="LineNr">278 </span>   <span class="Constant"> .recipe foo x:_elem -&gt; z:_elem [                   ╎                                                 .</span>
-<span id="L279" class="LineNr">279 </span>   <span class="Constant"> .  local-scope                                     ╎─────────────────────────────────────────────────.</span>
-<span id="L280" class="LineNr">280 </span>   <span class="Constant"> .  load-ingredients                                ╎0   edit          copy            delete         .</span>
-<span id="L281" class="LineNr">281 </span>   <span class="Constant"> .  y:&amp;:num &lt;- copy 0                               ╎foo 2                                            .</span>
-<span id="L282" class="LineNr">282 </span>   <span class="Constant"> .  z &lt;- add x, y                                   ╎foo_2: 'add' requires number ingredients, but go↩.</span>
-<span id="L283" class="LineNr">283 </span>   <span class="Constant"> .]                                                 ╎t 'y'                                            .</span>
-<span id="L284" class="LineNr">284 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L285" class="LineNr">285 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
-<span id="L286" class="LineNr">286 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L277" class="LineNr">277 </span>  <span class="Conceal">¦</span><span class="Constant"> .  errors found (0)                                                               run (F4)           .</span>
+<span id="L278" class="LineNr">278 </span>  <span class="Conceal">¦</span><span class="Constant"> .recipe foo x:_elem -&gt; z:_elem [                   ╎                                                 .</span>
+<span id="L279" class="LineNr">279 </span>  <span class="Conceal">¦</span><span class="Constant"> .  local-scope                                     ╎─────────────────────────────────────────────────.</span>
+<span id="L280" class="LineNr">280 </span>  <span class="Conceal">¦</span><span class="Constant"> .  load-ingredients                                ╎0   edit          copy            delete         .</span>
+<span id="L281" class="LineNr">281 </span>  <span class="Conceal">¦</span><span class="Constant"> .  y:&amp;:num &lt;- copy 0                               ╎foo 2                                            .</span>
+<span id="L282" class="LineNr">282 </span>  <span class="Conceal">¦</span><span class="Constant"> .  z &lt;- add x, y                                   ╎foo_2: 'add' requires number ingredients, but go↩.</span>
+<span id="L283" class="LineNr">283 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎t 'y'                                            .</span>
+<span id="L284" class="LineNr">284 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L285" class="LineNr">285 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
+<span id="L286" class="LineNr">286 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L287" class="LineNr">287 </span>  ]
 <span id="L288" class="LineNr">288 </span>  <span class="Comment"># now rerun everything</span>
 <span id="L289" class="LineNr">289 </span>  assume-console [
-<span id="L290" class="LineNr">290 </span>    press F4
+<span id="L290" class="LineNr">290 </span>  <span class="Conceal">¦</span> press F4
 <span id="L291" class="LineNr">291 </span>  ]
 <span id="L292" class="LineNr">292 </span>  run [
-<span id="L293" class="LineNr">293 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L293" class="LineNr">293 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L294" class="LineNr">294 </span>  ]
 <span id="L295" class="LineNr">295 </span>  <span class="Comment"># error should remain unchanged</span>
 <span id="L296" class="LineNr">296 </span>  screen-should-contain [
-<span id="L297" class="LineNr">297 </span>   <span class="Constant"> .  errors found (0)                                                               run (F4)           .</span>
-<span id="L298" class="LineNr">298 </span>   <span class="Constant"> .recipe foo x:_elem -&gt; z:_elem [                   ╎                                                 .</span>
-<span id="L299" class="LineNr">299 </span>   <span class="Constant"> .  local-scope                                     ╎─────────────────────────────────────────────────.</span>
-<span id="L300" class="LineNr">300 </span>   <span class="Constant"> .  load-ingredients                                ╎0   edit          copy            delete         .</span>
-<span id="L301" class="LineNr">301 </span>   <span class="Constant"> .  y:&amp;:num &lt;- copy 0                               ╎foo 2                                            .</span>
-<span id="L302" class="LineNr">302 </span>   <span class="Constant"> .  z &lt;- add x, y                                   ╎foo_3: 'add' requires number ingredients, but go↩.</span>
-<span id="L303" class="LineNr">303 </span>   <span class="Constant"> .]                                                 ╎t 'y'                                            .</span>
-<span id="L304" class="LineNr">304 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L305" class="LineNr">305 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
-<span id="L306" class="LineNr">306 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L297" class="LineNr">297 </span>  <span class="Conceal">¦</span><span class="Constant"> .  errors found (0)                                                               run (F4)           .</span>
+<span id="L298" class="LineNr">298 </span>  <span class="Conceal">¦</span><span class="Constant"> .recipe foo x:_elem -&gt; z:_elem [                   ╎                                                 .</span>
+<span id="L299" class="LineNr">299 </span>  <span class="Conceal">¦</span><span class="Constant"> .  local-scope                                     ╎─────────────────────────────────────────────────.</span>
+<span id="L300" class="LineNr">300 </span>  <span class="Conceal">¦</span><span class="Constant"> .  load-ingredients                                ╎0   edit          copy            delete         .</span>
+<span id="L301" class="LineNr">301 </span>  <span class="Conceal">¦</span><span class="Constant"> .  y:&amp;:num &lt;- copy 0                               ╎foo 2                                            .</span>
+<span id="L302" class="LineNr">302 </span>  <span class="Conceal">¦</span><span class="Constant"> .  z &lt;- add x, y                                   ╎foo_3: 'add' requires number ingredients, but go↩.</span>
+<span id="L303" class="LineNr">303 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎t 'y'                                            .</span>
+<span id="L304" class="LineNr">304 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L305" class="LineNr">305 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
+<span id="L306" class="LineNr">306 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L307" class="LineNr">307 </span>  ]
 <span id="L308" class="LineNr">308 </span>]
 <span id="L309" class="LineNr">309 </span>
@@ -374,10 +375,10 @@ if ('onhashchange' in window) {
 <span id="L313" class="LineNr">313 </span>  assume-screen <span class="Constant">100/width</span>, <span class="Constant">15/height</span>
 <span id="L314" class="LineNr">314 </span>  <span class="Comment"># overload a well-known shape-shifting recipe</span>
 <span id="L315" class="LineNr">315 </span>  assume-resources [
-<span id="L316" class="LineNr">316 </span>    <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
-<span id="L317" class="LineNr">317 </span>      <span class="Constant">|recipe</span> length l:&amp;:list:_elem<span class="muRecipe"> -&gt; </span>n:num <span class="Constant">[|</span>
-<span id="L318" class="LineNr">318 </span><span class="Constant">      |]</span>|
-<span id="L319" class="LineNr">319 </span>    ]
+<span id="L316" class="LineNr">316 </span>  <span class="Conceal">¦</span> <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
+<span id="L317" class="LineNr">317 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Constant">|recipe</span> length l:&amp;:list:_elem<span class="muRecipe"> -&gt; </span>n:num <span class="Constant">[|</span>
+<span id="L318" class="LineNr">318 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |]</span>|
+<span id="L319" class="LineNr">319 </span>  <span class="Conceal">¦</span> ]
 <span id="L320" class="LineNr">320 </span>  ]
 <span id="L321" class="LineNr">321 </span>  <span class="Comment"># call code that uses other variants of it, but not it itself</span>
 <span id="L322" class="LineNr">322 </span>  test-sandbox:text <span class="Special">&lt;-</span> new <span class="Constant">[x:&amp;:list:num &lt;- copy 0</span>
@@ -385,51 +386,51 @@ if ('onhashchange' in window) {
 <span id="L324" class="LineNr">324 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, test-sandbox
 <span id="L325" class="LineNr">325 </span>  <span class="Comment"># run it once</span>
 <span id="L326" class="LineNr">326 </span>  assume-console [
-<span id="L327" class="LineNr">327 </span>    press F4
+<span id="L327" class="LineNr">327 </span>  <span class="Conceal">¦</span> press F4
 <span id="L328" class="LineNr">328 </span>  ]
 <span id="L329" class="LineNr">329 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L330" class="LineNr">330 </span>  <span class="Comment"># no errors anywhere on screen (can't check anything else, since to-text will return an address)</span>
 <span id="L331" class="LineNr">331 </span>  screen-should-contain-in-color <span class="Constant">1/red</span>, [
-<span id="L332" class="LineNr">332 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L333" class="LineNr">333 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L334" class="LineNr">334 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L335" class="LineNr">335 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L336" class="LineNr">336 </span>   <span class="Constant"> .                                                                &lt;-                                  .</span>
-<span id="L337" class="LineNr">337 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L338" class="LineNr">338 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L339" class="LineNr">339 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L340" class="LineNr">340 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L341" class="LineNr">341 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L342" class="LineNr">342 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L343" class="LineNr">343 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L344" class="LineNr">344 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L345" class="LineNr">345 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L346" class="LineNr">346 </span>   <span class="Constant"> .                                                                                                    .</span>
+<span id="L332" class="LineNr">332 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L333" class="LineNr">333 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L334" class="LineNr">334 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L335" class="LineNr">335 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L336" class="LineNr">336 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                &lt;-                                  .</span>
+<span id="L337" class="LineNr">337 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L338" class="LineNr">338 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L339" class="LineNr">339 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L340" class="LineNr">340 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L341" class="LineNr">341 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L342" class="LineNr">342 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L343" class="LineNr">343 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L344" class="LineNr">344 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L345" class="LineNr">345 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L346" class="LineNr">346 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
 <span id="L347" class="LineNr">347 </span>  ]
 <span id="L348" class="LineNr">348 </span>  <span class="Comment"># rerun everything</span>
 <span id="L349" class="LineNr">349 </span>  assume-console [
-<span id="L350" class="LineNr">350 </span>    press F4
+<span id="L350" class="LineNr">350 </span>  <span class="Conceal">¦</span> press F4
 <span id="L351" class="LineNr">351 </span>  ]
 <span id="L352" class="LineNr">352 </span>  run [
-<span id="L353" class="LineNr">353 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L353" class="LineNr">353 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L354" class="LineNr">354 </span>  ]
 <span id="L355" class="LineNr">355 </span>  <span class="Comment"># still no errors</span>
 <span id="L356" class="LineNr">356 </span>  screen-should-contain-in-color <span class="Constant">1/red</span>, [
-<span id="L357" class="LineNr">357 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L358" class="LineNr">358 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L359" class="LineNr">359 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L360" class="LineNr">360 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L361" class="LineNr">361 </span>   <span class="Constant"> .                                                                &lt;-                                  .</span>
-<span id="L362" class="LineNr">362 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L363" class="LineNr">363 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L364" class="LineNr">364 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L365" class="LineNr">365 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L366" class="LineNr">366 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L367" class="LineNr">367 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L368" class="LineNr">368 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L369" class="LineNr">369 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L370" class="LineNr">370 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L371" class="LineNr">371 </span>   <span class="Constant"> .                                                                                                    .</span>
+<span id="L357" class="LineNr">357 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L358" class="LineNr">358 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L359" class="LineNr">359 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L360" class="LineNr">360 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L361" class="LineNr">361 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                &lt;-                                  .</span>
+<span id="L362" class="LineNr">362 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L363" class="LineNr">363 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L364" class="LineNr">364 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L365" class="LineNr">365 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L366" class="LineNr">366 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L367" class="LineNr">367 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L368" class="LineNr">368 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L369" class="LineNr">369 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L370" class="LineNr">370 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L371" class="LineNr">371 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
 <span id="L372" class="LineNr">372 </span>  ]
 <span id="L373" class="LineNr">373 </span>]
 <span id="L374" class="LineNr">374 </span>
@@ -438,29 +439,29 @@ if ('onhashchange' in window) {
 <span id="L377" class="LineNr">377 </span>  trace-until <span class="Constant">100/app</span>  <span class="Comment"># trace too long</span>
 <span id="L378" class="LineNr">378 </span>  assume-screen <span class="Constant">100/width</span>, <span class="Constant">15/height</span>
 <span id="L379" class="LineNr">379 </span>  assume-resources [
-<span id="L380" class="LineNr">380 </span>    <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
-<span id="L381" class="LineNr">381 </span>      <span class="Constant">|recipe</span> foo <span class="Constant">[|</span>
-<span id="L382" class="LineNr">382 </span><span class="Constant">      |  x &lt;- copy 0|</span>
-<span id="L383" class="LineNr">383 </span><span class="Constant">      |]</span>|
-<span id="L384" class="LineNr">384 </span>    ]
+<span id="L380" class="LineNr">380 </span>  <span class="Conceal">¦</span> <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
+<span id="L381" class="LineNr">381 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Constant">|recipe</span> foo <span class="Constant">[|</span>
+<span id="L382" class="LineNr">382 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  x &lt;- copy 0|</span>
+<span id="L383" class="LineNr">383 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |]</span>|
+<span id="L384" class="LineNr">384 </span>  <span class="Conceal">¦</span> ]
 <span id="L385" class="LineNr">385 </span>  ]
 <span id="L386" class="LineNr">386 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[foo]</span>
 <span id="L387" class="LineNr">387 </span>  assume-console [
-<span id="L388" class="LineNr">388 </span>    press F4
+<span id="L388" class="LineNr">388 </span>  <span class="Conceal">¦</span> press F4
 <span id="L389" class="LineNr">389 </span>  ]
 <span id="L390" class="LineNr">390 </span>  run [
-<span id="L391" class="LineNr">391 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L391" class="LineNr">391 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L392" class="LineNr">392 </span>  ]
 <span id="L393" class="LineNr">393 </span>  screen-should-contain [
-<span id="L394" class="LineNr">394 </span>   <span class="Constant"> .  errors found                                                                   run (F4)           .</span>
-<span id="L395" class="LineNr">395 </span>   <span class="Constant"> .recipe foo [                                      ╎foo                                              .</span>
-<span id="L396" class="LineNr">396 </span>   <span class="Constant"> .  x &lt;- copy 0                                     ╎─────────────────────────────────────────────────.</span>
-<span id="L397" class="LineNr">397 </span>   <span class="Constant"> .]                                                 ╎                                                 .</span>
-<span id="L398" class="LineNr">398 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L399" class="LineNr">399 </span>   <span class="Constant"> .foo: missing type for 'x' in 'x &lt;- copy 0'        ╎                                                 .</span>
-<span id="L400" class="LineNr">400 </span>   <span class="Constant"> .foo: can't copy '0' to 'x'; types don't match     ╎                                                 .</span>
-<span id="L401" class="LineNr">401 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
-<span id="L402" class="LineNr">402 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L394" class="LineNr">394 </span>  <span class="Conceal">¦</span><span class="Constant"> .  errors found                                                                   run (F4)           .</span>
+<span id="L395" class="LineNr">395 </span>  <span class="Conceal">¦</span><span class="Constant"> .recipe foo [                                      ╎foo                                              .</span>
+<span id="L396" class="LineNr">396 </span>  <span class="Conceal">¦</span><span class="Constant"> .  x &lt;- copy 0                                     ╎─────────────────────────────────────────────────.</span>
+<span id="L397" class="LineNr">397 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎                                                 .</span>
+<span id="L398" class="LineNr">398 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L399" class="LineNr">399 </span>  <span class="Conceal">¦</span><span class="Constant"> .foo: missing type for 'x' in 'x &lt;- copy 0'        ╎                                                 .</span>
+<span id="L400" class="LineNr">400 </span>  <span class="Conceal">¦</span><span class="Constant"> .foo: can't copy '0' to 'x'; types don't match     ╎                                                 .</span>
+<span id="L401" class="LineNr">401 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
+<span id="L402" class="LineNr">402 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L403" class="LineNr">403 </span>  ]
 <span id="L404" class="LineNr">404 </span>]
 <span id="L405" class="LineNr">405 </span>
@@ -470,26 +471,26 @@ if ('onhashchange' in window) {
 <span id="L409" class="LineNr">409 </span>  assume-screen <span class="Constant">100/width</span>, <span class="Constant">15/height</span>
 <span id="L410" class="LineNr">410 </span>  <span class="Comment"># recipe is incomplete (unbalanced '[')</span>
 <span id="L411" class="LineNr">411 </span>  assume-resources [
-<span id="L412" class="LineNr">412 </span>    <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
-<span id="L413" class="LineNr">413 </span>      <span class="Constant">|recipe</span> foo \\\<span class="Constant">[|</span>
-<span id="L414" class="LineNr">414 </span><span class="Constant">      |  x &lt;- copy 0|</span>
-<span id="L415" class="LineNr">415 </span><span class="Constant">    ]</span>
+<span id="L412" class="LineNr">412 </span>  <span class="Conceal">¦</span> <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
+<span id="L413" class="LineNr">413 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Constant">|recipe</span> foo \\\<span class="Constant">[|</span>
+<span id="L414" class="LineNr">414 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  x &lt;- copy 0|</span>
+<span id="L415" class="LineNr">415 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> ]</span>
 <span id="L416" class="LineNr">416 </span>  ]
 <span id="L417" class="LineNr">417 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[foo]</span>
 <span id="L418" class="LineNr">418 </span>  assume-console [
-<span id="L419" class="LineNr">419 </span>    press F4
+<span id="L419" class="LineNr">419 </span>  <span class="Conceal">¦</span> press F4
 <span id="L420" class="LineNr">420 </span>  ]
 <span id="L421" class="LineNr">421 </span>  run [
-<span id="L422" class="LineNr">422 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L422" class="LineNr">422 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L423" class="LineNr">423 </span>  ]
 <span id="L424" class="LineNr">424 </span>  screen-should-contain [
-<span id="L425" class="LineNr">425 </span>   <span class="Constant"> .  errors found                                                                   run (F4)           .</span>
-<span id="L426" class="LineNr">426 </span>   <span class="Constant"> .recipe foo \\[                                      ╎foo                                              .</span>
-<span id="L427" class="LineNr">427 </span>   <span class="Constant"> .  x &lt;- copy 0                                     ╎─────────────────────────────────────────────────.</span>
-<span id="L428" class="LineNr">428 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L429" class="LineNr">429 </span>   <span class="Constant"> .9: unbalanced '\\[' for recipe                      ╎                                                 .</span>
-<span id="L430" class="LineNr">430 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
-<span id="L431" class="LineNr">431 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L425" class="LineNr">425 </span>  <span class="Conceal">¦</span><span class="Constant"> .  errors found                                                                   run (F4)           .</span>
+<span id="L426" class="LineNr">426 </span>  <span class="Conceal">¦</span><span class="Constant"> .recipe foo \\[                                      ╎foo                                              .</span>
+<span id="L427" class="LineNr">427 </span>  <span class="Conceal">¦</span><span class="Constant"> .  x &lt;- copy 0                                     ╎─────────────────────────────────────────────────.</span>
+<span id="L428" class="LineNr">428 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L429" class="LineNr">429 </span>  <span class="Conceal">¦</span><span class="Constant"> .9: unbalanced '\\[' for recipe                      ╎                                                 .</span>
+<span id="L430" class="LineNr">430 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
+<span id="L431" class="LineNr">431 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L432" class="LineNr">432 </span>  ]
 <span id="L433" class="LineNr">433 </span>]
 <span id="L434" class="LineNr">434 </span>
@@ -498,33 +499,33 @@ if ('onhashchange' in window) {
 <span id="L437" class="LineNr">437 </span>  trace-until <span class="Constant">100/app</span>  <span class="Comment"># trace too long</span>
 <span id="L438" class="LineNr">438 </span>  assume-screen <span class="Constant">100/width</span>, <span class="Constant">15/height</span>
 <span id="L439" class="LineNr">439 </span>  assume-resources [
-<span id="L440" class="LineNr">440 </span>    <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
-<span id="L441" class="LineNr">441 </span>      <span class="Constant">|recipe</span> foo <span class="Constant">[|</span>
-<span id="L442" class="LineNr">442 </span><span class="Constant">      |  local-scope|</span>
-<span id="L443" class="LineNr">443 </span><span class="Constant">      |  x:&amp;:point &lt;- new point:type|</span>
-<span id="L444" class="LineNr">444 </span><span class="Constant">      |  get x:&amp;:point, 1:offset|</span>
-<span id="L445" class="LineNr">445 </span><span class="Constant">      |]</span>|
-<span id="L446" class="LineNr">446 </span>    ]
+<span id="L440" class="LineNr">440 </span>  <span class="Conceal">¦</span> <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
+<span id="L441" class="LineNr">441 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Constant">|recipe</span> foo <span class="Constant">[|</span>
+<span id="L442" class="LineNr">442 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  local-scope|</span>
+<span id="L443" class="LineNr">443 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  x:&amp;:point &lt;- new point:type|</span>
+<span id="L444" class="LineNr">444 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  get x:&amp;:point, 1:offset|</span>
+<span id="L445" class="LineNr">445 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |]</span>|
+<span id="L446" class="LineNr">446 </span>  <span class="Conceal">¦</span> ]
 <span id="L447" class="LineNr">447 </span>  ]
 <span id="L448" class="LineNr">448 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[foo]</span>
 <span id="L449" class="LineNr">449 </span>  assume-console [
-<span id="L450" class="LineNr">450 </span>    press F4
+<span id="L450" class="LineNr">450 </span>  <span class="Conceal">¦</span> press F4
 <span id="L451" class="LineNr">451 </span>  ]
 <span id="L452" class="LineNr">452 </span>  run [
-<span id="L453" class="LineNr">453 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L453" class="LineNr">453 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L454" class="LineNr">454 </span>  ]
 <span id="L455" class="LineNr">455 </span>  screen-should-contain [
-<span id="L456" class="LineNr">456 </span>   <span class="Constant"> .  errors found                                                                   run (F4)           .</span>
-<span id="L457" class="LineNr">457 </span>   <span class="Constant"> .recipe foo [                                      ╎foo                                              .</span>
-<span id="L458" class="LineNr">458 </span>   <span class="Constant"> .  local-scope                                     ╎─────────────────────────────────────────────────.</span>
-<span id="L459" class="LineNr">459 </span>   <span class="Constant"> .  x:&amp;:point &lt;- new point:type                     ╎                                                 .</span>
-<span id="L460" class="LineNr">460 </span>   <span class="Constant"> .  get x:&amp;:point, 1:offset                         ╎                                                 .</span>
-<span id="L461" class="LineNr">461 </span>   <span class="Constant"> .]                                                 ╎                                                 .</span>
-<span id="L462" class="LineNr">462 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L463" class="LineNr">463 </span>   <span class="Constant"> .foo: first ingredient of 'get' should be a contai↩╎                                                 .</span>
-<span id="L464" class="LineNr">464 </span>   <span class="Constant"> .ner, but got 'x:&amp;:point'                          ╎                                                 .</span>
-<span id="L465" class="LineNr">465 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
-<span id="L466" class="LineNr">466 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L456" class="LineNr">456 </span>  <span class="Conceal">¦</span><span class="Constant"> .  errors found                                                                   run (F4)           .</span>
+<span id="L457" class="LineNr">457 </span>  <span class="Conceal">¦</span><span class="Constant"> .recipe foo [                                      ╎foo                                              .</span>
+<span id="L458" class="LineNr">458 </span>  <span class="Conceal">¦</span><span class="Constant"> .  local-scope                                     ╎─────────────────────────────────────────────────.</span>
+<span id="L459" class="LineNr">459 </span>  <span class="Conceal">¦</span><span class="Constant"> .  x:&amp;:point &lt;- new point:type                     ╎                                                 .</span>
+<span id="L460" class="LineNr">460 </span>  <span class="Conceal">¦</span><span class="Constant"> .  get x:&amp;:point, 1:offset                         ╎                                                 .</span>
+<span id="L461" class="LineNr">461 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎                                                 .</span>
+<span id="L462" class="LineNr">462 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L463" class="LineNr">463 </span>  <span class="Conceal">¦</span><span class="Constant"> .foo: first ingredient of 'get' should be a contai↩╎                                                 .</span>
+<span id="L464" class="LineNr">464 </span>  <span class="Conceal">¦</span><span class="Constant"> .ner, but got 'x:&amp;:point'                          ╎                                                 .</span>
+<span id="L465" class="LineNr">465 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
+<span id="L466" class="LineNr">466 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L467" class="LineNr">467 </span>  ]
 <span id="L468" class="LineNr">468 </span>]
 <span id="L469" class="LineNr">469 </span>
@@ -533,35 +534,35 @@ if ('onhashchange' in window) {
 <span id="L472" class="LineNr">472 </span>  trace-until <span class="Constant">100/app</span>  <span class="Comment"># trace too long</span>
 <span id="L473" class="LineNr">473 </span>  assume-screen <span class="Constant">100/width</span>, <span class="Constant">15/height</span>
 <span id="L474" class="LineNr">474 </span>  assume-resources [
-<span id="L475" class="LineNr">475 </span>    <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
-<span id="L476" class="LineNr">476 </span>      <span class="Constant">|recipe</span> foo <span class="Constant">[|</span>
-<span id="L477" class="LineNr">477 </span><span class="Constant">      |  local-scope|</span>
-<span id="L478" class="LineNr">478 </span><span class="Constant">      |  x:num &lt;- copy 0|</span>
-<span id="L479" class="LineNr">479 </span><span class="Constant">      |  y:&amp;:point &lt;- new point:type|</span>
-<span id="L480" class="LineNr">480 </span><span class="Constant">      |  get *y:&amp;:point, x:num|</span>
-<span id="L481" class="LineNr">481 </span><span class="Constant">      |]</span>|
-<span id="L482" class="LineNr">482 </span>    ]
+<span id="L475" class="LineNr">475 </span>  <span class="Conceal">¦</span> <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
+<span id="L476" class="LineNr">476 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Constant">|recipe</span> foo <span class="Constant">[|</span>
+<span id="L477" class="LineNr">477 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  local-scope|</span>
+<span id="L478" class="LineNr">478 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  x:num &lt;- copy 0|</span>
+<span id="L479" class="LineNr">479 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  y:&amp;:point &lt;- new point:type|</span>
+<span id="L480" class="LineNr">480 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  get *y:&amp;:point, x:num|</span>
+<span id="L481" class="LineNr">481 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |]</span>|
+<span id="L482" class="LineNr">482 </span>  <span class="Conceal">¦</span> ]
 <span id="L483" class="LineNr">483 </span>  ]
 <span id="L484" class="LineNr">484 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[foo]</span>
 <span id="L485" class="LineNr">485 </span>  assume-console [
-<span id="L486" class="LineNr">486 </span>    press F4
+<span id="L486" class="LineNr">486 </span>  <span class="Conceal">¦</span> press F4
 <span id="L487" class="LineNr">487 </span>  ]
 <span id="L488" class="LineNr">488 </span>  run [
-<span id="L489" class="LineNr">489 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L489" class="LineNr">489 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L490" class="LineNr">490 </span>  ]
 <span id="L491" class="LineNr">491 </span>  screen-should-contain [
-<span id="L492" class="LineNr">492 </span>   <span class="Constant"> .  errors found                                                                   run (F4)           .</span>
-<span id="L493" class="LineNr">493 </span>   <span class="Constant"> .recipe foo [                                      ╎foo                                              .</span>
-<span id="L494" class="LineNr">494 </span>   <span class="Constant"> .  local-scope                                     ╎─────────────────────────────────────────────────.</span>
-<span id="L495" class="LineNr">495 </span>   <span class="Constant"> .  x:num &lt;- copy 0                                 ╎                                                 .</span>
-<span id="L496" class="LineNr">496 </span>   <span class="Constant"> .  y:&amp;:point &lt;- new point:type                     ╎                                                 .</span>
-<span id="L497" class="LineNr">497 </span>   <span class="Constant"> .  get *y:&amp;:point, x:num                           ╎                                                 .</span>
-<span id="L498" class="LineNr">498 </span>   <span class="Constant"> .]                                                 ╎                                                 .</span>
-<span id="L499" class="LineNr">499 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L500" class="LineNr">500 </span>   <span class="Constant"> .foo: second ingredient of 'get' should have type ↩╎                                                 .</span>
-<span id="L501" class="LineNr">501 </span>   <span class="Constant"> .'offset', but got 'x:num'                         ╎                                                 .</span>
-<span id="L502" class="LineNr">502 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
-<span id="L503" class="LineNr">503 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L492" class="LineNr">492 </span>  <span class="Conceal">¦</span><span class="Constant"> .  errors found                                                                   run (F4)           .</span>
+<span id="L493" class="LineNr">493 </span>  <span class="Conceal">¦</span><span class="Constant"> .recipe foo [                                      ╎foo                                              .</span>
+<span id="L494" class="LineNr">494 </span>  <span class="Conceal">¦</span><span class="Constant"> .  local-scope                                     ╎─────────────────────────────────────────────────.</span>
+<span id="L495" class="LineNr">495 </span>  <span class="Conceal">¦</span><span class="Constant"> .  x:num &lt;- copy 0                                 ╎                                                 .</span>
+<span id="L496" class="LineNr">496 </span>  <span class="Conceal">¦</span><span class="Constant"> .  y:&amp;:point &lt;- new point:type                     ╎                                                 .</span>
+<span id="L497" class="LineNr">497 </span>  <span class="Conceal">¦</span><span class="Constant"> .  get *y:&amp;:point, x:num                           ╎                                                 .</span>
+<span id="L498" class="LineNr">498 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎                                                 .</span>
+<span id="L499" class="LineNr">499 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L500" class="LineNr">500 </span>  <span class="Conceal">¦</span><span class="Constant"> .foo: second ingredient of 'get' should have type ↩╎                                                 .</span>
+<span id="L501" class="LineNr">501 </span>  <span class="Conceal">¦</span><span class="Constant"> .'offset', but got 'x:num'                         ╎                                                 .</span>
+<span id="L502" class="LineNr">502 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
+<span id="L503" class="LineNr">503 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L504" class="LineNr">504 </span>  ]
 <span id="L505" class="LineNr">505 </span>]
 <span id="L506" class="LineNr">506 </span>
@@ -571,48 +572,48 @@ if ('onhashchange' in window) {
 <span id="L510" class="LineNr">510 </span>  assume-screen <span class="Constant">100/width</span>, <span class="Constant">15/height</span>
 <span id="L511" class="LineNr">511 </span>  <span class="Comment"># try to run a file with an error</span>
 <span id="L512" class="LineNr">512 </span>  assume-resources [
-<span id="L513" class="LineNr">513 </span>    <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
-<span id="L514" class="LineNr">514 </span>      <span class="Constant">|recipe</span> foo <span class="Constant">[|</span>
-<span id="L515" class="LineNr">515 </span><span class="Constant">      |  local-scope|</span>
-<span id="L516" class="LineNr">516 </span><span class="Constant">      |  x:num &lt;- copy y:num|</span>
-<span id="L517" class="LineNr">517 </span><span class="Constant">      |]</span>|
-<span id="L518" class="LineNr">518 </span>    ]
+<span id="L513" class="LineNr">513 </span>  <span class="Conceal">¦</span> <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
+<span id="L514" class="LineNr">514 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Constant">|recipe</span> foo <span class="Constant">[|</span>
+<span id="L515" class="LineNr">515 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  local-scope|</span>
+<span id="L516" class="LineNr">516 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  x:num &lt;- copy y:num|</span>
+<span id="L517" class="LineNr">517 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |]</span>|
+<span id="L518" class="LineNr">518 </span>  <span class="Conceal">¦</span> ]
 <span id="L519" class="LineNr">519 </span>  ]
 <span id="L520" class="LineNr">520 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[foo]</span>
 <span id="L521" class="LineNr">521 </span>  assume-console [
-<span id="L522" class="LineNr">522 </span>    press F4
+<span id="L522" class="LineNr">522 </span>  <span class="Conceal">¦</span> press F4
 <span id="L523" class="LineNr">523 </span>  ]
 <span id="L524" class="LineNr">524 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L525" class="LineNr">525 </span>  screen-should-contain [
-<span id="L526" class="LineNr">526 </span>   <span class="Constant"> .  errors found                                                                   run (F4)           .</span>
-<span id="L527" class="LineNr">527 </span>   <span class="Constant"> .recipe foo [                                      ╎foo                                              .</span>
-<span id="L528" class="LineNr">528 </span>   <span class="Constant"> .  local-scope                                     ╎─────────────────────────────────────────────────.</span>
-<span id="L529" class="LineNr">529 </span>   <span class="Constant"> .  x:num &lt;- copy y:num                             ╎                                                 .</span>
-<span id="L530" class="LineNr">530 </span>   <span class="Constant"> .]                                                 ╎                                                 .</span>
-<span id="L531" class="LineNr">531 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L532" class="LineNr">532 </span>   <span class="Constant"> .foo: tried to read ingredient 'y' in 'x:num &lt;- co↩╎                                                 .</span>
-<span id="L533" class="LineNr">533 </span>   <span class="Constant"> .py y:num' but it hasn't been written to yet       ╎                                                 .</span>
-<span id="L534" class="LineNr">534 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
-<span id="L535" class="LineNr">535 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L526" class="LineNr">526 </span>  <span class="Conceal">¦</span><span class="Constant"> .  errors found                                                                   run (F4)           .</span>
+<span id="L527" class="LineNr">527 </span>  <span class="Conceal">¦</span><span class="Constant"> .recipe foo [                                      ╎foo                                              .</span>
+<span id="L528" class="LineNr">528 </span>  <span class="Conceal">¦</span><span class="Constant"> .  local-scope                                     ╎─────────────────────────────────────────────────.</span>
+<span id="L529" class="LineNr">529 </span>  <span class="Conceal">¦</span><span class="Constant"> .  x:num &lt;- copy y:num                             ╎                                                 .</span>
+<span id="L530" class="LineNr">530 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎                                                 .</span>
+<span id="L531" class="LineNr">531 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L532" class="LineNr">532 </span>  <span class="Conceal">¦</span><span class="Constant"> .foo: tried to read ingredient 'y' in 'x:num &lt;- co↩╎                                                 .</span>
+<span id="L533" class="LineNr">533 </span>  <span class="Conceal">¦</span><span class="Constant"> .py y:num' but it hasn't been written to yet       ╎                                                 .</span>
+<span id="L534" class="LineNr">534 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
+<span id="L535" class="LineNr">535 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L536" class="LineNr">536 </span>  ]
 <span id="L537" class="LineNr">537 </span>  <span class="Comment"># rerun the file, check for the same error</span>
 <span id="L538" class="LineNr">538 </span>  assume-console [
-<span id="L539" class="LineNr">539 </span>    press F4
+<span id="L539" class="LineNr">539 </span>  <span class="Conceal">¦</span> press F4
 <span id="L540" class="LineNr">540 </span>  ]
 <span id="L541" class="LineNr">541 </span>  run [
-<span id="L542" class="LineNr">542 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L542" class="LineNr">542 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L543" class="LineNr">543 </span>  ]
 <span id="L544" class="LineNr">544 </span>  screen-should-contain [
-<span id="L545" class="LineNr">545 </span>   <span class="Constant"> .  errors found                                                                   run (F4)           .</span>
-<span id="L546" class="LineNr">546 </span>   <span class="Constant"> .recipe foo [                                      ╎foo                                              .</span>
-<span id="L547" class="LineNr">547 </span>   <span class="Constant"> .  local-scope                                     ╎─────────────────────────────────────────────────.</span>
-<span id="L548" class="LineNr">548 </span>   <span class="Constant"> .  x:num &lt;- copy y:num                             ╎                                                 .</span>
-<span id="L549" class="LineNr">549 </span>   <span class="Constant"> .]                                                 ╎                                                 .</span>
-<span id="L550" class="LineNr">550 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L551" class="LineNr">551 </span>   <span class="Constant"> .foo: tried to read ingredient 'y' in 'x:num &lt;- co↩╎                                                 .</span>
-<span id="L552" class="LineNr">552 </span>   <span class="Constant"> .py y:num' but it hasn't been written to yet       ╎                                                 .</span>
-<span id="L553" class="LineNr">553 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
-<span id="L554" class="LineNr">554 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L545" class="LineNr">545 </span>  <span class="Conceal">¦</span><span class="Constant"> .  errors found                                                                   run (F4)           .</span>
+<span id="L546" class="LineNr">546 </span>  <span class="Conceal">¦</span><span class="Constant"> .recipe foo [                                      ╎foo                                              .</span>
+<span id="L547" class="LineNr">547 </span>  <span class="Conceal">¦</span><span class="Constant"> .  local-scope                                     ╎─────────────────────────────────────────────────.</span>
+<span id="L548" class="LineNr">548 </span>  <span class="Conceal">¦</span><span class="Constant"> .  x:num &lt;- copy y:num                             ╎                                                 .</span>
+<span id="L549" class="LineNr">549 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎                                                 .</span>
+<span id="L550" class="LineNr">550 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L551" class="LineNr">551 </span>  <span class="Conceal">¦</span><span class="Constant"> .foo: tried to read ingredient 'y' in 'x:num &lt;- co↩╎                                                 .</span>
+<span id="L552" class="LineNr">552 </span>  <span class="Conceal">¦</span><span class="Constant"> .py y:num' but it hasn't been written to yet       ╎                                                 .</span>
+<span id="L553" class="LineNr">553 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
+<span id="L554" class="LineNr">554 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L555" class="LineNr">555 </span>  ]
 <span id="L556" class="LineNr">556 </span>]
 <span id="L557" class="LineNr">557 </span>
@@ -625,56 +626,56 @@ if ('onhashchange' in window) {
 <span id="L564" class="LineNr">564 </span>  <span class="Comment"># sandbox editor contains an illegal instruction</span>
 <span id="L565" class="LineNr">565 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[get 1234:num, foo:offset]</span>
 <span id="L566" class="LineNr">566 </span>  assume-console [
-<span id="L567" class="LineNr">567 </span>    press F4
+<span id="L567" class="LineNr">567 </span>  <span class="Conceal">¦</span> press F4
 <span id="L568" class="LineNr">568 </span>  ]
 <span id="L569" class="LineNr">569 </span>  run [
-<span id="L570" class="LineNr">570 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L570" class="LineNr">570 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L571" class="LineNr">571 </span>  ]
 <span id="L572" class="LineNr">572 </span>  <span class="Comment"># check that screen prints error message in red</span>
 <span id="L573" class="LineNr">573 </span>  screen-should-contain [
-<span id="L574" class="LineNr">574 </span>   <span class="Constant"> .  errors found (0)                                                               run (F4)           .</span>
-<span id="L575" class="LineNr">575 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L576" class="LineNr">576 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L577" class="LineNr">577 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L578" class="LineNr">578 </span>   <span class="Constant"> .                                                  ╎get 1234:num, foo:offset                         .</span>
-<span id="L579" class="LineNr">579 </span>   <span class="Constant"> .                                                  ╎unknown element 'foo' in container 'number'      .</span>
-<span id="L580" class="LineNr">580 </span>   <span class="Constant"> .                                                  ╎first ingredient of 'get' should be a container,↩.</span>
-<span id="L581" class="LineNr">581 </span>   <span class="Constant"> .                                                  ╎ but got '1234:num'                              .</span>
-<span id="L582" class="LineNr">582 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L583" class="LineNr">583 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L574" class="LineNr">574 </span>  <span class="Conceal">¦</span><span class="Constant"> .  errors found (0)                                                               run (F4)           .</span>
+<span id="L575" class="LineNr">575 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L576" class="LineNr">576 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L577" class="LineNr">577 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L578" class="LineNr">578 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎get 1234:num, foo:offset                         .</span>
+<span id="L579" class="LineNr">579 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎unknown element 'foo' in container 'number'      .</span>
+<span id="L580" class="LineNr">580 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎first ingredient of 'get' should be a container,↩.</span>
+<span id="L581" class="LineNr">581 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎ but got '1234:num'                              .</span>
+<span id="L582" class="LineNr">582 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L583" class="LineNr">583 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L584" class="LineNr">584 </span>  ]
 <span id="L585" class="LineNr">585 </span>  screen-should-contain-in-color <span class="Constant">7/white</span>, [
-<span id="L586" class="LineNr">586 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L587" class="LineNr">587 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L588" class="LineNr">588 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L589" class="LineNr">589 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L590" class="LineNr">590 </span>   <span class="Constant"> .                                                   get 1234:num, foo:offset                         .</span>
-<span id="L591" class="LineNr">591 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L592" class="LineNr">592 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L593" class="LineNr">593 </span>   <span class="Constant"> .                                                                                                    .</span>
+<span id="L586" class="LineNr">586 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L587" class="LineNr">587 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L588" class="LineNr">588 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L589" class="LineNr">589 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L590" class="LineNr">590 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                   get 1234:num, foo:offset                         .</span>
+<span id="L591" class="LineNr">591 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L592" class="LineNr">592 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L593" class="LineNr">593 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
 <span id="L594" class="LineNr">594 </span>  ]
 <span id="L595" class="LineNr">595 </span>  screen-should-contain-in-color <span class="Constant">1/red</span>, [
-<span id="L596" class="LineNr">596 </span>   <span class="Constant"> .  errors found (0)                                                                                  .</span>
-<span id="L597" class="LineNr">597 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L598" class="LineNr">598 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L599" class="LineNr">599 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L600" class="LineNr">600 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L601" class="LineNr">601 </span>   <span class="Constant"> .                                                   unknown element 'foo' in container 'number'      .</span>
-<span id="L602" class="LineNr">602 </span>   <span class="Constant"> .                                                   first ingredient of 'get' should be a container, .</span>
-<span id="L603" class="LineNr">603 </span>   <span class="Constant"> .                                                    but got '1234:num'                              .</span>
-<span id="L604" class="LineNr">604 </span>   <span class="Constant"> .                                                                                                    .</span>
+<span id="L596" class="LineNr">596 </span>  <span class="Conceal">¦</span><span class="Constant"> .  errors found (0)                                                                                  .</span>
+<span id="L597" class="LineNr">597 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L598" class="LineNr">598 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L599" class="LineNr">599 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L600" class="LineNr">600 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L601" class="LineNr">601 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                   unknown element 'foo' in container 'number'      .</span>
+<span id="L602" class="LineNr">602 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                   first ingredient of 'get' should be a container, .</span>
+<span id="L603" class="LineNr">603 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                    but got '1234:num'                              .</span>
+<span id="L604" class="LineNr">604 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
 <span id="L605" class="LineNr">605 </span>  ]
 <span id="L606" class="LineNr">606 </span>  screen-should-contain-in-color <span class="Constant">245/grey</span>, [
-<span id="L607" class="LineNr">607 </span>   <span class="Constant"> .                                                                                                    .</span>
-<span id="L608" class="LineNr">608 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L609" class="LineNr">609 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L610" class="LineNr">610 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L611" class="LineNr">611 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L612" class="LineNr">612 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L613" class="LineNr">613 </span>   <span class="Constant"> .                                                  ╎                                                ↩.</span>
-<span id="L614" class="LineNr">614 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L615" class="LineNr">615 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L616" class="LineNr">616 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L607" class="LineNr">607 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L608" class="LineNr">608 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L609" class="LineNr">609 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L610" class="LineNr">610 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L611" class="LineNr">611 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L612" class="LineNr">612 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L613" class="LineNr">613 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                ↩.</span>
+<span id="L614" class="LineNr">614 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L615" class="LineNr">615 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L616" class="LineNr">616 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L617" class="LineNr">617 </span>  ]
 <span id="L618" class="LineNr">618 </span>]
 <span id="L619" class="LineNr">619 </span>
@@ -688,24 +689,24 @@ if ('onhashchange' in window) {
 <span id="L627" class="LineNr">627 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[get 1234:num, foo:offset]</span>
 <span id="L628" class="LineNr">628 </span>  <span class="Comment"># run the code in the editors multiple times</span>
 <span id="L629" class="LineNr">629 </span>  assume-console [
-<span id="L630" class="LineNr">630 </span>    press F4
-<span id="L631" class="LineNr">631 </span>    press F4
+<span id="L630" class="LineNr">630 </span>  <span class="Conceal">¦</span> press F4
+<span id="L631" class="LineNr">631 </span>  <span class="Conceal">¦</span> press F4
 <span id="L632" class="LineNr">632 </span>  ]
 <span id="L633" class="LineNr">633 </span>  run [
-<span id="L634" class="LineNr">634 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L634" class="LineNr">634 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L635" class="LineNr">635 </span>  ]
 <span id="L636" class="LineNr">636 </span>  <span class="Comment"># check that screen prints error message just once</span>
 <span id="L637" class="LineNr">637 </span>  screen-should-contain [
-<span id="L638" class="LineNr">638 </span>   <span class="Constant"> .  errors found (0)                                                               run (F4)           .</span>
-<span id="L639" class="LineNr">639 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L640" class="LineNr">640 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
-<span id="L641" class="LineNr">641 </span>   <span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
-<span id="L642" class="LineNr">642 </span>   <span class="Constant"> .                                                  ╎get 1234:num, foo:offset                         .</span>
-<span id="L643" class="LineNr">643 </span>   <span class="Constant"> .                                                  ╎unknown element 'foo' in container 'number'      .</span>
-<span id="L644" class="LineNr">644 </span>   <span class="Constant"> .                                                  ╎first ingredient of 'get' should be a container,↩.</span>
-<span id="L645" class="LineNr">645 </span>   <span class="Constant"> .                                                  ╎ but got '1234:num'                              .</span>
-<span id="L646" class="LineNr">646 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L647" class="LineNr">647 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L638" class="LineNr">638 </span>  <span class="Conceal">¦</span><span class="Constant"> .  errors found (0)                                                               run (F4)           .</span>
+<span id="L639" class="LineNr">639 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L640" class="LineNr">640 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎─────────────────────────────────────────────────.</span>
+<span id="L641" class="LineNr">641 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎0   edit          copy            delete         .</span>
+<span id="L642" class="LineNr">642 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎get 1234:num, foo:offset                         .</span>
+<span id="L643" class="LineNr">643 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎unknown element 'foo' in container 'number'      .</span>
+<span id="L644" class="LineNr">644 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎first ingredient of 'get' should be a container,↩.</span>
+<span id="L645" class="LineNr">645 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎ but got '1234:num'                              .</span>
+<span id="L646" class="LineNr">646 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L647" class="LineNr">647 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L648" class="LineNr">648 </span>  ]
 <span id="L649" class="LineNr">649 </span>]
 <span id="L650" class="LineNr">650 </span>
@@ -715,32 +716,32 @@ if ('onhashchange' in window) {
 <span id="L654" class="LineNr">654 </span>  assume-screen <span class="Constant">100/width</span>, <span class="Constant">20/height</span>
 <span id="L655" class="LineNr">655 </span>  <span class="Comment"># sandbox editor will trigger an infinite loop</span>
 <span id="L656" class="LineNr">656 </span>  assume-resources [
-<span id="L657" class="LineNr">657 </span>    <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
-<span id="L658" class="LineNr">658 </span>      <span class="Constant">|recipe</span> foo <span class="Constant">[|</span>
-<span id="L659" class="LineNr">659 </span><span class="Constant">      |  {|</span>
-<span id="L660" class="LineNr">660 </span><span class="Constant">      |    loop|</span>
-<span id="L661" class="LineNr">661 </span><span class="Constant">      |  }|</span>
-<span id="L662" class="LineNr">662 </span><span class="Constant">      |]</span>|
-<span id="L663" class="LineNr">663 </span>    ]
+<span id="L657" class="LineNr">657 </span>  <span class="Conceal">¦</span> <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
+<span id="L658" class="LineNr">658 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Constant">|recipe</span> foo <span class="Constant">[|</span>
+<span id="L659" class="LineNr">659 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  {|</span>
+<span id="L660" class="LineNr">660 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |    loop|</span>
+<span id="L661" class="LineNr">661 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  }|</span>
+<span id="L662" class="LineNr">662 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |]</span>|
+<span id="L663" class="LineNr">663 </span>  <span class="Conceal">¦</span> ]
 <span id="L664" class="LineNr">664 </span>  ]
 <span id="L665" class="LineNr">665 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[foo]</span>
 <span id="L666" class="LineNr">666 </span>  <span class="Comment"># run the sandbox</span>
 <span id="L667" class="LineNr">667 </span>  assume-console [
-<span id="L668" class="LineNr">668 </span>    press F4
+<span id="L668" class="LineNr">668 </span>  <span class="Conceal">¦</span> press F4
 <span id="L669" class="LineNr">669 </span>  ]
 <span id="L670" class="LineNr">670 </span>  run [
-<span id="L671" class="LineNr">671 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L671" class="LineNr">671 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L672" class="LineNr">672 </span>  ]
 <span id="L673" class="LineNr">673 </span>  screen-should-contain [
-<span id="L674" class="LineNr">674 </span>   <span class="Constant"> .  errors found (0)                                                               run (F4)           .</span>
-<span id="L675" class="LineNr">675 </span>   <span class="Constant"> .recipe foo [                                      ╎                                                 .</span>
-<span id="L676" class="LineNr">676 </span>   <span class="Constant"> .  {                                               ╎─────────────────────────────────────────────────.</span>
-<span id="L677" class="LineNr">677 </span>   <span class="Constant"> .    loop                                          ╎0   edit          copy            delete         .</span>
-<span id="L678" class="LineNr">678 </span>   <span class="Constant"> .  }                                               ╎foo                                              .</span>
-<span id="L679" class="LineNr">679 </span>   <span class="Constant"> .]                                                 ╎took too long!                                   .</span>
-<span id="L680" class="LineNr">680 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L681" class="LineNr">681 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
-<span id="L682" class="LineNr">682 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L674" class="LineNr">674 </span>  <span class="Conceal">¦</span><span class="Constant"> .  errors found (0)                                                               run (F4)           .</span>
+<span id="L675" class="LineNr">675 </span>  <span class="Conceal">¦</span><span class="Constant"> .recipe foo [                                      ╎                                                 .</span>
+<span id="L676" class="LineNr">676 </span>  <span class="Conceal">¦</span><span class="Constant"> .  {                                               ╎─────────────────────────────────────────────────.</span>
+<span id="L677" class="LineNr">677 </span>  <span class="Conceal">¦</span><span class="Constant"> .    loop                                          ╎0   edit          copy            delete         .</span>
+<span id="L678" class="LineNr">678 </span>  <span class="Conceal">¦</span><span class="Constant"> .  }                                               ╎foo                                              .</span>
+<span id="L679" class="LineNr">679 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎took too long!                                   .</span>
+<span id="L680" class="LineNr">680 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L681" class="LineNr">681 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
+<span id="L682" class="LineNr">682 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L683" class="LineNr">683 </span>  ]
 <span id="L684" class="LineNr">684 </span>]
 <span id="L685" class="LineNr">685 </span>
@@ -750,55 +751,55 @@ if ('onhashchange' in window) {
 <span id="L689" class="LineNr">689 </span>  assume-screen <span class="Constant">100/width</span>, <span class="Constant">10/height</span>
 <span id="L690" class="LineNr">690 </span>  <span class="Comment"># generate a stash and a error</span>
 <span id="L691" class="LineNr">691 </span>  assume-resources [
-<span id="L692" class="LineNr">692 </span>    <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
-<span id="L693" class="LineNr">693 </span>      <span class="Constant">|recipe</span> foo <span class="Constant">[|</span>
-<span id="L694" class="LineNr">694 </span><span class="Constant">      |  local-scope|</span>
-<span id="L695" class="LineNr">695 </span><span class="Constant">      |  a:num &lt;- next-ingredient|</span>
-<span id="L696" class="LineNr">696 </span><span class="Constant">      |  b:num &lt;- next-ingredient|</span>
-<span id="L697" class="LineNr">697 </span><span class="Constant">      |  stash [dividing by]</span>, b|
-<span id="L698" class="LineNr">698 </span>      <span class="Constant">|</span>  _, c:num <span class="Special">&lt;-</span> divide-with-remainder a, b|
-<span id="L699" class="LineNr">699 </span>      <span class="Constant">|</span>  <span class="muControl">reply</span> b|
-<span id="L700" class="LineNr">700 </span><span class="Constant">      |]|</span>
-<span id="L701" class="LineNr">701 </span>    ]
+<span id="L692" class="LineNr">692 </span>  <span class="Conceal">¦</span> <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
+<span id="L693" class="LineNr">693 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Constant">|recipe</span> foo <span class="Constant">[|</span>
+<span id="L694" class="LineNr">694 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  local-scope|</span>
+<span id="L695" class="LineNr">695 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  a:num &lt;- next-ingredient|</span>
+<span id="L696" class="LineNr">696 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  b:num &lt;- next-ingredient|</span>
+<span id="L697" class="LineNr">697 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |  stash [dividing by]</span>, b|
+<span id="L698" class="LineNr">698 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Constant">|</span>  _, c:num <span class="Special">&lt;-</span> divide-with-remainder a, b|
+<span id="L699" class="LineNr">699 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Constant">|</span>  <span class="muControl">reply</span> b|
+<span id="L700" class="LineNr">700 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> |]|</span>
+<span id="L701" class="LineNr">701 </span>  <span class="Conceal">¦</span> ]
 <span id="L702" class="LineNr">702 </span>  ]
 <span id="L703" class="LineNr">703 </span>  env:&amp;:environment <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L21'>new-programming-environment</a> <a href='../088file.mu.html#L11'>resources</a>, <a href='../081print.mu.html#L4'>screen</a>, <span class="Constant">[foo 4, 0]</span>
 <span id="L704" class="LineNr">704 </span>  <span class="Comment"># run</span>
 <span id="L705" class="LineNr">705 </span>  assume-console [
-<span id="L706" class="LineNr">706 </span>    press F4
+<span id="L706" class="LineNr">706 </span>  <span class="Conceal">¦</span> press F4
 <span id="L707" class="LineNr">707 </span>  ]
 <span id="L708" class="LineNr">708 </span>  <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L709" class="LineNr">709 </span>  <span class="Comment"># screen prints error message</span>
 <span id="L710" class="LineNr">710 </span>  screen-should-contain [
-<span id="L711" class="LineNr">711 </span>   <span class="Constant"> .  errors found (0)                                                               run (F4)           .</span>
-<span id="L712" class="LineNr">712 </span>   <span class="Constant"> .recipe foo [                                      ╎                                                 .</span>
-<span id="L713" class="LineNr">713 </span>   <span class="Constant"> .  local-scope                                     ╎─────────────────────────────────────────────────.</span>
-<span id="L714" class="LineNr">714 </span>   <span class="Constant"> .  a:num &lt;- next-ingredient                        ╎0   edit          copy            delete         .</span>
-<span id="L715" class="LineNr">715 </span>   <span class="Constant"> .  b:num &lt;- next-ingredient                        ╎foo 4, 0                                         .</span>
-<span id="L716" class="LineNr">716 </span>   <span class="Constant"> .  stash [dividing by], b                          ╎foo: divide by zero in '_, c:num &lt;- divide-with-↩.</span>
-<span id="L717" class="LineNr">717 </span>   <span class="Constant"> .  _, c:num &lt;- divide-with-remainder a, b          ╎remainder a, b'                                  .</span>
-<span id="L718" class="LineNr">718 </span>   <span class="Constant"> .  reply b                                         ╎─────────────────────────────────────────────────.</span>
-<span id="L719" class="LineNr">719 </span>   <span class="Constant"> .]                                                 ╎                                                 .</span>
-<span id="L720" class="LineNr">720 </span>   <span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L711" class="LineNr">711 </span>  <span class="Conceal">¦</span><span class="Constant"> .  errors found (0)                                                               run (F4)           .</span>
+<span id="L712" class="LineNr">712 </span>  <span class="Conceal">¦</span><span class="Constant"> .recipe foo [                                      ╎                                                 .</span>
+<span id="L713" class="LineNr">713 </span>  <span class="Conceal">¦</span><span class="Constant"> .  local-scope                                     ╎─────────────────────────────────────────────────.</span>
+<span id="L714" class="LineNr">714 </span>  <span class="Conceal">¦</span><span class="Constant"> .  a:num &lt;- next-ingredient                        ╎0   edit          copy            delete         .</span>
+<span id="L715" class="LineNr">715 </span>  <span class="Conceal">¦</span><span class="Constant"> .  b:num &lt;- next-ingredient                        ╎foo 4, 0                                         .</span>
+<span id="L716" class="LineNr">716 </span>  <span class="Conceal">¦</span><span class="Constant"> .  stash [dividing by], b                          ╎foo: divide by zero in '_, c:num &lt;- divide-with-↩.</span>
+<span id="L717" class="LineNr">717 </span>  <span class="Conceal">¦</span><span class="Constant"> .  _, c:num &lt;- divide-with-remainder a, b          ╎remainder a, b'                                  .</span>
+<span id="L718" class="LineNr">718 </span>  <span class="Conceal">¦</span><span class="Constant"> .  reply b                                         ╎─────────────────────────────────────────────────.</span>
+<span id="L719" class="LineNr">719 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎                                                 .</span>
+<span id="L720" class="LineNr">720 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L721" class="LineNr">721 </span>  ]
 <span id="L722" class="LineNr">722 </span>  <span class="Comment"># click on the call in the sandbox</span>
 <span id="L723" class="LineNr">723 </span>  assume-console [
-<span id="L724" class="LineNr">724 </span>    left-click<span class="Constant"> 4</span>,<span class="Constant"> 55</span>
+<span id="L724" class="LineNr">724 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 4</span>,<span class="Constant"> 55</span>
 <span id="L725" class="LineNr">725 </span>  ]
 <span id="L726" class="LineNr">726 </span>  run [
-<span id="L727" class="LineNr">727 </span>    <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L727" class="LineNr">727 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
 <span id="L728" class="LineNr">728 </span>  ]
 <span id="L729" class="LineNr">729 </span>  <span class="Comment"># screen should expand trace</span>
 <span id="L730" class="LineNr">730 </span>  screen-should-contain [
-<span id="L731" class="LineNr">731 </span>   <span class="Constant"> .  errors found (0)                                                               run (F4)           .</span>
-<span id="L732" class="LineNr">732 </span>   <span class="Constant"> .recipe foo [                                      ╎                                                 .</span>
-<span id="L733" class="LineNr">733 </span>   <span class="Constant"> .  local-scope                                     ╎─────────────────────────────────────────────────.</span>
-<span id="L734" class="LineNr">734 </span>   <span class="Constant"> .  a:num &lt;- next-ingredient                        ╎0   edit          copy            delete         .</span>
-<span id="L735" class="LineNr">735 </span>   <span class="Constant"> .  b:num &lt;- next-ingredient                        ╎foo 4, 0                                         .</span>
-<span id="L736" class="LineNr">736 </span>   <span class="Constant"> .  stash [dividing by], b                          ╎dividing by 0                                    .</span>
-<span id="L737" class="LineNr">737 </span>   <span class="Constant"> .  _, c:num &lt;- divide-with-remainder a, b          ╎14 instructions run                              .</span>
-<span id="L738" class="LineNr">738 </span>   <span class="Constant"> .  reply b                                         ╎foo: divide by zero in '_, c:num &lt;- divide-with-↩.</span>
-<span id="L739" class="LineNr">739 </span>   <span class="Constant"> .]                                                 ╎remainder a, b'                                  .</span>
-<span id="L740" class="LineNr">740 </span>   <span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L731" class="LineNr">731 </span>  <span class="Conceal">¦</span><span class="Constant"> .  errors found (0)                                                               run (F4)           .</span>
+<span id="L732" class="LineNr">732 </span>  <span class="Conceal">¦</span><span class="Constant"> .recipe foo [                                      ╎                                                 .</span>
+<span id="L733" class="LineNr">733 </span>  <span class="Conceal">¦</span><span class="Constant"> .  local-scope                                     ╎─────────────────────────────────────────────────.</span>
+<span id="L734" class="LineNr">734 </span>  <span class="Conceal">¦</span><span class="Constant"> .  a:num &lt;- next-ingredient                        ╎0   edit          copy            delete         .</span>
+<span id="L735" class="LineNr">735 </span>  <span class="Conceal">¦</span><span class="Constant"> .  b:num &lt;- next-ingredient                        ╎foo 4, 0                                         .</span>
+<span id="L736" class="LineNr">736 </span>  <span class="Conceal">¦</span><span class="Constant"> .  stash [dividing by], b                          ╎dividing by 0                                    .</span>
+<span id="L737" class="LineNr">737 </span>  <span class="Conceal">¦</span><span class="Constant"> .  _, c:num &lt;- divide-with-remainder a, b          ╎14 instructions run                              .</span>
+<span id="L738" class="LineNr">738 </span>  <span class="Conceal">¦</span><span class="Constant"> .  reply b                                         ╎foo: divide by zero in '_, c:num &lt;- divide-with-↩.</span>
+<span id="L739" class="LineNr">739 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎remainder a, b'                                  .</span>
+<span id="L740" class="LineNr">740 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
 <span id="L741" class="LineNr">741 </span>  ]
 <span id="L742" class="LineNr">742 </span>]
 </pre>
diff --git a/html/edit/012-editor-undo.mu.html b/html/edit/012-editor-undo.mu.html
index 023ecc94..39255865 100644
--- a/html/edit/012-editor-undo.mu.html
+++ b/html/edit/012-editor-undo.mu.html
@@ -15,16 +15,17 @@ body { font-size: 12pt; font-family: monospace; color: #eeeeee; background-color
 a { text-decoration: none; }
 a:hover { text-decoration: underline; }
 * { font-size: 12pt; font-size: 1em; }
-.muData { color: #ffff00; }
-.muControl { color: #c0a020; }
+.Conceal { color: #4e4e4e; }
+.muRecipe { color: #ff8700; }
 .Special { color: #c00000; }
 .Delimiter { color: #800080; }
 .SalientComment { color: #00ffff; }
 .Constant { color: #00a0a0; }
 .LineNr { color: #444444; }
 .Comment { color: #9090ff; }
-.muRecipe { color: #ff8700; }
+.muControl { color: #c0a020; }
 .muScenario { color: #00af00; }
+.muData { color: #ffff00; }
 -->
 </style>
 
@@ -80,8 +81,8 @@ if ('onhashchange' in window) {
 <span id="L19" class="LineNr">  19 </span>  insert-from:&amp;:duplex-list:char
 <span id="L20" class="LineNr">  20 </span>  insert-until:&amp;:duplex-list:char
 <span id="L21" class="LineNr">  21 </span>  tag:num  <span class="Comment"># event causing this operation; might be used to coalesce runs of similar events</span>
-<span id="L22" class="LineNr">  22 </span>    <span class="Comment"># 0: no coalesce (enter+indent)</span>
-<span id="L23" class="LineNr">  23 </span>    <span class="Comment"># 1: regular alphanumeric characters</span>
+<span id="L22" class="LineNr">  22 </span>  <span class="Conceal">¦</span> <span class="Comment"># 0: no coalesce (enter+indent)</span>
+<span id="L23" class="LineNr">  23 </span>  <span class="Conceal">¦</span> <span class="Comment"># 1: regular alphanumeric characters</span>
 <span id="L24" class="LineNr">  24 </span>]
 <span id="L25" class="LineNr">  25 </span>
 <span id="L26" class="LineNr">  26 </span><span class="muData">container</span> <a href='012-editor-undo.mu.html#L26'>move-operation</a> [
@@ -92,11 +93,11 @@ if ('onhashchange' in window) {
 <span id="L31" class="LineNr">  31 </span>  after-column:num
 <span id="L32" class="LineNr">  32 </span>  after-top-of-screen:&amp;:duplex-list:char
 <span id="L33" class="LineNr">  33 </span>  tag:num  <span class="Comment"># event causing this operation; might be used to coalesce runs of similar events</span>
-<span id="L34" class="LineNr">  34 </span>    <span class="Comment"># 0: no coalesce (touch events, etc)</span>
-<span id="L35" class="LineNr">  35 </span>    <span class="Comment"># 1: left arrow</span>
-<span id="L36" class="LineNr">  36 </span>    <span class="Comment"># 2: right arrow</span>
-<span id="L37" class="LineNr">  37 </span>    <span class="Comment"># 3: up arrow</span>
-<span id="L38" class="LineNr">  38 </span>    <span class="Comment"># 4: down arrow</span>
+<span id="L34" class="LineNr">  34 </span>  <span class="Conceal">¦</span> <span class="Comment"># 0: no coalesce (touch events, etc)</span>
+<span id="L35" class="LineNr">  35 </span>  <span class="Conceal">¦</span> <span class="Comment"># 1: left arrow</span>
+<span id="L36" class="LineNr">  36 </span>  <span class="Conceal">¦</span> <span class="Comment"># 2: right arrow</span>
+<span id="L37" class="LineNr">  37 </span>  <span class="Conceal">¦</span> <span class="Comment"># 3: up arrow</span>
+<span id="L38" class="LineNr">  38 </span>  <span class="Conceal">¦</span> <span class="Comment"># 4: down arrow</span>
 <span id="L39" class="LineNr">  39 </span>]
 <span id="L40" class="LineNr">  40 </span>
 <span id="L41" class="LineNr">  41 </span><span class="muData">container</span> <a href='012-editor-undo.mu.html#L41'>delete-operation</a> [
@@ -110,9 +111,9 @@ if ('onhashchange' in window) {
 <span id="L49" class="LineNr">  49 </span>  delete-from:&amp;:duplex-list:char
 <span id="L50" class="LineNr">  50 </span>  delete-until:&amp;:duplex-list:char
 <span id="L51" class="LineNr">  51 </span>  tag:num  <span class="Comment"># event causing this operation; might be used to coalesce runs of similar events</span>
-<span id="L52" class="LineNr">  52 </span>    <span class="Comment"># 0: no coalesce (ctrl-k, ctrl-u)</span>
-<span id="L53" class="LineNr">  53 </span>    <span class="Comment"># 1: backspace</span>
-<span id="L54" class="LineNr">  54 </span>    <span class="Comment"># 2: delete</span>
+<span id="L52" class="LineNr">  52 </span>  <span class="Conceal">¦</span> <span class="Comment"># 0: no coalesce (ctrl-k, ctrl-u)</span>
+<span id="L53" class="LineNr">  53 </span>  <span class="Conceal">¦</span> <span class="Comment"># 1: backspace</span>
+<span id="L54" class="LineNr">  54 </span>  <span class="Conceal">¦</span> <span class="Comment"># 2: delete</span>
 <span id="L55" class="LineNr">  55 </span>]
 <span id="L56" class="LineNr">  56 </span>
 <span id="L57" class="LineNr">  57 </span><span class="Comment"># every editor accumulates a list of operations to undo/redo</span>
@@ -124,36 +125,36 @@ if ('onhashchange' in window) {
 <span id="L63" class="LineNr">  63 </span><span class="Comment"># ctrl-z - undo operation</span>
 <span id="L64" class="LineNr">  64 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L183'>&lt;handle-special-character&gt;</a></span> [
 <span id="L65" class="LineNr">  65 </span>  <span class="Delimiter">{</span>
-<span id="L66" class="LineNr">  66 </span>    undo?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">26/ctrl-z</span>
-<span id="L67" class="LineNr">  67 </span>    <span class="muControl">break-unless</span> undo?
-<span id="L68" class="LineNr">  68 </span>    undo:&amp;:list:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">undo:offset</span>
-<span id="L69" class="LineNr">  69 </span>    <span class="muControl">break-unless</span> undo
-<span id="L70" class="LineNr">  70 </span>    op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> first undo
-<span id="L71" class="LineNr">  71 </span>    undo <span class="Special">&lt;-</span> <a href='../064list.mu.html#L25'>rest</a> undo
-<span id="L72" class="LineNr">  72 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">undo:offset</span>, undo
-<span id="L73" class="LineNr">  73 </span>    redo:&amp;:list:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">redo:offset</span>
-<span id="L74" class="LineNr">  74 </span>    redo <span class="Special">&lt;-</span> push op, redo
-<span id="L75" class="LineNr">  75 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">redo:offset</span>, redo
-<span id="L76" class="LineNr">  76 </span><span class="Constant">    <a href='012-editor-undo.mu.html#L76'>&lt;handle-undo&gt;</a></span>
-<span id="L77" class="LineNr">  77 </span>    <span class="muControl">return</span> <span class="Constant">1/go-render</span>
+<span id="L66" class="LineNr">  66 </span>  <span class="Conceal">¦</span> undo?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">26/ctrl-z</span>
+<span id="L67" class="LineNr">  67 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> undo?
+<span id="L68" class="LineNr">  68 </span>  <span class="Conceal">¦</span> undo:&amp;:list:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">undo:offset</span>
+<span id="L69" class="LineNr">  69 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> undo
+<span id="L70" class="LineNr">  70 </span>  <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> first undo
+<span id="L71" class="LineNr">  71 </span>  <span class="Conceal">¦</span> undo <span class="Special">&lt;-</span> <a href='../064list.mu.html#L25'>rest</a> undo
+<span id="L72" class="LineNr">  72 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">undo:offset</span>, undo
+<span id="L73" class="LineNr">  73 </span>  <span class="Conceal">¦</span> redo:&amp;:list:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">redo:offset</span>
+<span id="L74" class="LineNr">  74 </span>  <span class="Conceal">¦</span> redo <span class="Special">&lt;-</span> push op, redo
+<span id="L75" class="LineNr">  75 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">redo:offset</span>, redo
+<span id="L76" class="LineNr">  76 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> <a href='012-editor-undo.mu.html#L76'>&lt;handle-undo&gt;</a></span>
+<span id="L77" class="LineNr">  77 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">1/go-render</span>
 <span id="L78" class="LineNr">  78 </span>  <span class="Delimiter">}</span>
 <span id="L79" class="LineNr">  79 </span>]
 <span id="L80" class="LineNr">  80 </span>
 <span id="L81" class="LineNr">  81 </span><span class="Comment"># ctrl-y - redo operation</span>
 <span id="L82" class="LineNr">  82 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L183'>&lt;handle-special-character&gt;</a></span> [
 <span id="L83" class="LineNr">  83 </span>  <span class="Delimiter">{</span>
-<span id="L84" class="LineNr">  84 </span>    redo?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">25/ctrl-y</span>
-<span id="L85" class="LineNr">  85 </span>    <span class="muControl">break-unless</span> redo?
-<span id="L86" class="LineNr">  86 </span>    redo:&amp;:list:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">redo:offset</span>
-<span id="L87" class="LineNr">  87 </span>    <span class="muControl">break-unless</span> redo
-<span id="L88" class="LineNr">  88 </span>    op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> first redo
-<span id="L89" class="LineNr">  89 </span>    redo <span class="Special">&lt;-</span> <a href='../064list.mu.html#L25'>rest</a> redo
-<span id="L90" class="LineNr">  90 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">redo:offset</span>, redo
-<span id="L91" class="LineNr">  91 </span>    undo:&amp;:list:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">undo:offset</span>
-<span id="L92" class="LineNr">  92 </span>    undo <span class="Special">&lt;-</span> push op, undo
-<span id="L93" class="LineNr">  93 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">undo:offset</span>, undo
-<span id="L94" class="LineNr">  94 </span><span class="Constant">    <a href='012-editor-undo.mu.html#L94'>&lt;handle-redo&gt;</a></span>
-<span id="L95" class="LineNr">  95 </span>    <span class="muControl">return</span> <span class="Constant">1/go-render</span>
+<span id="L84" class="LineNr">  84 </span>  <span class="Conceal">¦</span> redo?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">25/ctrl-y</span>
+<span id="L85" class="LineNr">  85 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> redo?
+<span id="L86" class="LineNr">  86 </span>  <span class="Conceal">¦</span> redo:&amp;:list:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">redo:offset</span>
+<span id="L87" class="LineNr">  87 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> redo
+<span id="L88" class="LineNr">  88 </span>  <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> first redo
+<span id="L89" class="LineNr">  89 </span>  <span class="Conceal">¦</span> redo <span class="Special">&lt;-</span> <a href='../064list.mu.html#L25'>rest</a> redo
+<span id="L90" class="LineNr">  90 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">redo:offset</span>, redo
+<span id="L91" class="LineNr">  91 </span>  <span class="Conceal">¦</span> undo:&amp;:list:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">undo:offset</span>
+<span id="L92" class="LineNr">  92 </span>  <span class="Conceal">¦</span> undo <span class="Special">&lt;-</span> push op, undo
+<span id="L93" class="LineNr">  93 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">undo:offset</span>, undo
+<span id="L94" class="LineNr">  94 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> <a href='012-editor-undo.mu.html#L94'>&lt;handle-redo&gt;</a></span>
+<span id="L95" class="LineNr">  95 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">1/go-render</span>
 <span id="L96" class="LineNr">  96 </span>  <span class="Delimiter">}</span>
 <span id="L97" class="LineNr">  97 </span>]
 <span id="L98" class="LineNr">  98 </span>
@@ -166,35 +167,35 @@ if ('onhashchange' in window) {
 <span id="L105" class="LineNr"> 105 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> <span class="Constant">[]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L106" class="LineNr"> 106 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L107" class="LineNr"> 107 </span>  assume-console [
-<span id="L108" class="LineNr"> 108 </span>    type <span class="Constant">[0]</span>
+<span id="L108" class="LineNr"> 108 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
 <span id="L109" class="LineNr"> 109 </span>  ]
 <span id="L110" class="LineNr"> 110 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L111" class="LineNr"> 111 </span>  <span class="Comment"># undo</span>
 <span id="L112" class="LineNr"> 112 </span>  assume-console [
-<span id="L113" class="LineNr"> 113 </span>    press ctrl-z
+<span id="L113" class="LineNr"> 113 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L114" class="LineNr"> 114 </span>  ]
 <span id="L115" class="LineNr"> 115 </span>  run [
-<span id="L116" class="LineNr"> 116 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L116" class="LineNr"> 116 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L117" class="LineNr"> 117 </span>  ]
 <span id="L118" class="LineNr"> 118 </span>  <span class="Comment"># character should be gone</span>
 <span id="L119" class="LineNr"> 119 </span>  screen-should-contain [
-<span id="L120" class="LineNr"> 120 </span>   <span class="Constant"> .          .</span>
-<span id="L121" class="LineNr"> 121 </span>   <span class="Constant"> .          .</span>
-<span id="L122" class="LineNr"> 122 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L123" class="LineNr"> 123 </span>   <span class="Constant"> .          .</span>
+<span id="L120" class="LineNr"> 120 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L121" class="LineNr"> 121 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L122" class="LineNr"> 122 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L123" class="LineNr"> 123 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L124" class="LineNr"> 124 </span>  ]
 <span id="L125" class="LineNr"> 125 </span>  <span class="Comment"># cursor should be in the right place</span>
 <span id="L126" class="LineNr"> 126 </span>  assume-console [
-<span id="L127" class="LineNr"> 127 </span>    type <span class="Constant">[1]</span>
+<span id="L127" class="LineNr"> 127 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
 <span id="L128" class="LineNr"> 128 </span>  ]
 <span id="L129" class="LineNr"> 129 </span>  run [
-<span id="L130" class="LineNr"> 130 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L130" class="LineNr"> 130 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L131" class="LineNr"> 131 </span>  ]
 <span id="L132" class="LineNr"> 132 </span>  screen-should-contain [
-<span id="L133" class="LineNr"> 133 </span>   <span class="Constant"> .          .</span>
-<span id="L134" class="LineNr"> 134 </span>   <span class="Constant"> .1         .</span>
-<span id="L135" class="LineNr"> 135 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L136" class="LineNr"> 136 </span>   <span class="Constant"> .          .</span>
+<span id="L133" class="LineNr"> 133 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L134" class="LineNr"> 134 </span>  <span class="Conceal">¦</span><span class="Constant"> .1         .</span>
+<span id="L135" class="LineNr"> 135 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L136" class="LineNr"> 136 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L137" class="LineNr"> 137 </span>  ]
 <span id="L138" class="LineNr"> 138 </span>]
 <span id="L139" class="LineNr"> 139 </span>
@@ -209,21 +210,21 @@ if ('onhashchange' in window) {
 <span id="L148" class="LineNr"> 148 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
 <span id="L149" class="LineNr"> 149 </span>  undo:&amp;:list:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">undo:offset</span>
 <span id="L150" class="LineNr"> 150 </span>  <span class="Delimiter">{</span>
-<span id="L151" class="LineNr"> 151 </span>    <span class="Comment"># if previous operation was an insert, coalesce this operation with it</span>
-<span id="L152" class="LineNr"> 152 </span>    <span class="muControl">break-unless</span> undo
-<span id="L153" class="LineNr"> 153 </span>    op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> first undo
-<span id="L154" class="LineNr"> 154 </span>    typing:<a href='012-editor-undo.mu.html#L11'>insert-operation</a>, is-insert?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">typing:variant</span>
-<span id="L155" class="LineNr"> 155 </span>    <span class="muControl">break-unless</span> is-insert?
-<span id="L156" class="LineNr"> 156 </span>    previous-coalesce-tag:num <span class="Special">&lt;-</span> get typing, <span class="Constant">tag:offset</span>
-<span id="L157" class="LineNr"> 157 </span>    <span class="muControl">break-unless</span> previous-coalesce-tag
-<span id="L158" class="LineNr"> 158 </span>    before-cursor:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
-<span id="L159" class="LineNr"> 159 </span>    insert-until:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
-<span id="L160" class="LineNr"> 160 </span>    typing <span class="Special">&lt;-</span> put typing, <span class="Constant">insert-until:offset</span>, insert-until
-<span id="L161" class="LineNr"> 161 </span>    typing <span class="Special">&lt;-</span> put typing, <span class="Constant">after-row:offset</span>, cursor-row
-<span id="L162" class="LineNr"> 162 </span>    typing <span class="Special">&lt;-</span> put typing, <span class="Constant">after-column:offset</span>, cursor-column
-<span id="L163" class="LineNr"> 163 </span>    typing <span class="Special">&lt;-</span> put typing, <span class="Constant">after-top-of-screen:offset</span>, top-after
-<span id="L164" class="LineNr"> 164 </span>    *op <span class="Special">&lt;-</span> merge <span class="Constant">0/insert-operation</span>, typing
-<span id="L165" class="LineNr"> 165 </span>    <span class="muControl">break</span> <span class="Constant">+done-adding-insert-operation</span>
+<span id="L151" class="LineNr"> 151 </span>  <span class="Conceal">¦</span> <span class="Comment"># if previous operation was an insert, coalesce this operation with it</span>
+<span id="L152" class="LineNr"> 152 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> undo
+<span id="L153" class="LineNr"> 153 </span>  <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> first undo
+<span id="L154" class="LineNr"> 154 </span>  <span class="Conceal">¦</span> typing:<a href='012-editor-undo.mu.html#L11'>insert-operation</a>, is-insert?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">typing:variant</span>
+<span id="L155" class="LineNr"> 155 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-insert?
+<span id="L156" class="LineNr"> 156 </span>  <span class="Conceal">¦</span> previous-coalesce-tag:num <span class="Special">&lt;-</span> get typing, <span class="Constant">tag:offset</span>
+<span id="L157" class="LineNr"> 157 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> previous-coalesce-tag
+<span id="L158" class="LineNr"> 158 </span>  <span class="Conceal">¦</span> before-cursor:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
+<span id="L159" class="LineNr"> 159 </span>  <span class="Conceal">¦</span> insert-until:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L160" class="LineNr"> 160 </span>  <span class="Conceal">¦</span> typing <span class="Special">&lt;-</span> put typing, <span class="Constant">insert-until:offset</span>, insert-until
+<span id="L161" class="LineNr"> 161 </span>  <span class="Conceal">¦</span> typing <span class="Special">&lt;-</span> put typing, <span class="Constant">after-row:offset</span>, cursor-row
+<span id="L162" class="LineNr"> 162 </span>  <span class="Conceal">¦</span> typing <span class="Special">&lt;-</span> put typing, <span class="Constant">after-column:offset</span>, cursor-column
+<span id="L163" class="LineNr"> 163 </span>  <span class="Conceal">¦</span> typing <span class="Special">&lt;-</span> put typing, <span class="Constant">after-top-of-screen:offset</span>, top-after
+<span id="L164" class="LineNr"> 164 </span>  <span class="Conceal">¦</span> *op <span class="Special">&lt;-</span> merge <span class="Constant">0/insert-operation</span>, typing
+<span id="L165" class="LineNr"> 165 </span>  <span class="Conceal">¦</span> <span class="muControl">break</span> <span class="Constant">+done-adding-insert-operation</span>
 <span id="L166" class="LineNr"> 166 </span>  <span class="Delimiter">}</span>
 <span id="L167" class="LineNr"> 167 </span>  <span class="Comment"># if not, create a new operation</span>
 <span id="L168" class="LineNr"> 168 </span>  insert-from:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> cursor-before
@@ -271,20 +272,20 @@ if ('onhashchange' in window) {
 <span id="L210" class="LineNr"> 210 </span>
 <span id="L211" class="LineNr"> 211 </span><span class="muRecipe">after</span> <span class="Constant"><a href='012-editor-undo.mu.html#L76'>&lt;handle-undo&gt;</a></span> [
 <span id="L212" class="LineNr"> 212 </span>  <span class="Delimiter">{</span>
-<span id="L213" class="LineNr"> 213 </span>    typing:<a href='012-editor-undo.mu.html#L11'>insert-operation</a>, is-insert?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">typing:variant</span>
-<span id="L214" class="LineNr"> 214 </span>    <span class="muControl">break-unless</span> is-insert?
-<span id="L215" class="LineNr"> 215 </span>    start:&amp;:duplex-list:char <span class="Special">&lt;-</span> get typing, <span class="Constant">insert-from:offset</span>
-<span id="L216" class="LineNr"> 216 </span>    end:&amp;:duplex-list:char <span class="Special">&lt;-</span> get typing, <span class="Constant">insert-until:offset</span>
-<span id="L217" class="LineNr"> 217 </span>    <span class="Comment"># assert cursor-row/cursor-column/top-of-screen match after-row/after-column/after-top-of-screen</span>
-<span id="L218" class="LineNr"> 218 </span>    before-cursor:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> start
-<span id="L219" class="LineNr"> 219 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
-<span id="L220" class="LineNr"> 220 </span>    <a href='../065duplex_list.mu.html#L345'>remove-between</a> before-cursor, end
-<span id="L221" class="LineNr"> 221 </span>    cursor-row <span class="Special">&lt;-</span> get typing, <span class="Constant">before-row:offset</span>
-<span id="L222" class="LineNr"> 222 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
-<span id="L223" class="LineNr"> 223 </span>    cursor-column <span class="Special">&lt;-</span> get typing, <span class="Constant">before-column:offset</span>
-<span id="L224" class="LineNr"> 224 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
-<span id="L225" class="LineNr"> 225 </span>    top:&amp;:duplex-list:char <span class="Special">&lt;-</span> get typing, <span class="Constant">before-top-of-screen:offset</span>
-<span id="L226" class="LineNr"> 226 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top
+<span id="L213" class="LineNr"> 213 </span>  <span class="Conceal">¦</span> typing:<a href='012-editor-undo.mu.html#L11'>insert-operation</a>, is-insert?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">typing:variant</span>
+<span id="L214" class="LineNr"> 214 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-insert?
+<span id="L215" class="LineNr"> 215 </span>  <span class="Conceal">¦</span> start:&amp;:duplex-list:char <span class="Special">&lt;-</span> get typing, <span class="Constant">insert-from:offset</span>
+<span id="L216" class="LineNr"> 216 </span>  <span class="Conceal">¦</span> end:&amp;:duplex-list:char <span class="Special">&lt;-</span> get typing, <span class="Constant">insert-until:offset</span>
+<span id="L217" class="LineNr"> 217 </span>  <span class="Conceal">¦</span> <span class="Comment"># assert cursor-row/cursor-column/top-of-screen match after-row/after-column/after-top-of-screen</span>
+<span id="L218" class="LineNr"> 218 </span>  <span class="Conceal">¦</span> before-cursor:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> start
+<span id="L219" class="LineNr"> 219 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
+<span id="L220" class="LineNr"> 220 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L345'>remove-between</a> before-cursor, end
+<span id="L221" class="LineNr"> 221 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> get typing, <span class="Constant">before-row:offset</span>
+<span id="L222" class="LineNr"> 222 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
+<span id="L223" class="LineNr"> 223 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> get typing, <span class="Constant">before-column:offset</span>
+<span id="L224" class="LineNr"> 224 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
+<span id="L225" class="LineNr"> 225 </span>  <span class="Conceal">¦</span> top:&amp;:duplex-list:char <span class="Special">&lt;-</span> get typing, <span class="Constant">before-top-of-screen:offset</span>
+<span id="L226" class="LineNr"> 226 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top
 <span id="L227" class="LineNr"> 227 </span>  <span class="Delimiter">}</span>
 <span id="L228" class="LineNr"> 228 </span>]
 <span id="L229" class="LineNr"> 229 </span>
@@ -295,22 +296,22 @@ if ('onhashchange' in window) {
 <span id="L234" class="LineNr"> 234 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> <span class="Constant">[]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L235" class="LineNr"> 235 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L236" class="LineNr"> 236 </span>  assume-console [
-<span id="L237" class="LineNr"> 237 </span>    type <span class="Constant">[012]</span>
+<span id="L237" class="LineNr"> 237 </span>  <span class="Conceal">¦</span> type <span class="Constant">[012]</span>
 <span id="L238" class="LineNr"> 238 </span>  ]
 <span id="L239" class="LineNr"> 239 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L240" class="LineNr"> 240 </span>  <span class="Comment"># undo</span>
 <span id="L241" class="LineNr"> 241 </span>  assume-console [
-<span id="L242" class="LineNr"> 242 </span>    press ctrl-z
+<span id="L242" class="LineNr"> 242 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L243" class="LineNr"> 243 </span>  ]
 <span id="L244" class="LineNr"> 244 </span>  run [
-<span id="L245" class="LineNr"> 245 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L245" class="LineNr"> 245 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L246" class="LineNr"> 246 </span>  ]
 <span id="L247" class="LineNr"> 247 </span>  <span class="Comment"># all characters must be gone</span>
 <span id="L248" class="LineNr"> 248 </span>  screen-should-contain [
-<span id="L249" class="LineNr"> 249 </span>   <span class="Constant"> .          .</span>
-<span id="L250" class="LineNr"> 250 </span>   <span class="Constant"> .          .</span>
-<span id="L251" class="LineNr"> 251 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L252" class="LineNr"> 252 </span>   <span class="Constant"> .          .</span>
+<span id="L249" class="LineNr"> 249 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L250" class="LineNr"> 250 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L251" class="LineNr"> 251 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L252" class="LineNr"> 252 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L253" class="LineNr"> 253 </span>  ]
 <span id="L254" class="LineNr"> 254 </span>]
 <span id="L255" class="LineNr"> 255 </span>
@@ -322,41 +323,41 @@ if ('onhashchange' in window) {
 <span id="L261" class="LineNr"> 261 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L262" class="LineNr"> 262 </span>  <span class="Comment"># type some characters</span>
 <span id="L263" class="LineNr"> 263 </span>  assume-console [
-<span id="L264" class="LineNr"> 264 </span>    type <span class="Constant">[012]</span>
+<span id="L264" class="LineNr"> 264 </span>  <span class="Conceal">¦</span> type <span class="Constant">[012]</span>
 <span id="L265" class="LineNr"> 265 </span>  ]
 <span id="L266" class="LineNr"> 266 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L267" class="LineNr"> 267 </span>  screen-should-contain [
-<span id="L268" class="LineNr"> 268 </span>   <span class="Constant"> .          .</span>
-<span id="L269" class="LineNr"> 269 </span>   <span class="Constant"> .012a      .</span>
-<span id="L270" class="LineNr"> 270 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L271" class="LineNr"> 271 </span>   <span class="Constant"> .          .</span>
+<span id="L268" class="LineNr"> 268 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L269" class="LineNr"> 269 </span>  <span class="Conceal">¦</span><span class="Constant"> .012a      .</span>
+<span id="L270" class="LineNr"> 270 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L271" class="LineNr"> 271 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L272" class="LineNr"> 272 </span>  ]
 <span id="L273" class="LineNr"> 273 </span>  <span class="Comment"># undo</span>
 <span id="L274" class="LineNr"> 274 </span>  assume-console [
-<span id="L275" class="LineNr"> 275 </span>    press ctrl-z
+<span id="L275" class="LineNr"> 275 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L276" class="LineNr"> 276 </span>  ]
 <span id="L277" class="LineNr"> 277 </span>  run [
-<span id="L278" class="LineNr"> 278 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L278" class="LineNr"> 278 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L279" class="LineNr"> 279 </span>  ]
 <span id="L280" class="LineNr"> 280 </span>  <span class="Comment"># back to original text</span>
 <span id="L281" class="LineNr"> 281 </span>  screen-should-contain [
-<span id="L282" class="LineNr"> 282 </span>   <span class="Constant"> .          .</span>
-<span id="L283" class="LineNr"> 283 </span>   <span class="Constant"> .a         .</span>
-<span id="L284" class="LineNr"> 284 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L285" class="LineNr"> 285 </span>   <span class="Constant"> .          .</span>
+<span id="L282" class="LineNr"> 282 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L283" class="LineNr"> 283 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L284" class="LineNr"> 284 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L285" class="LineNr"> 285 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L286" class="LineNr"> 286 </span>  ]
 <span id="L287" class="LineNr"> 287 </span>  <span class="Comment"># cursor should be in the right place</span>
 <span id="L288" class="LineNr"> 288 </span>  assume-console [
-<span id="L289" class="LineNr"> 289 </span>    type <span class="Constant">[3]</span>
+<span id="L289" class="LineNr"> 289 </span>  <span class="Conceal">¦</span> type <span class="Constant">[3]</span>
 <span id="L290" class="LineNr"> 290 </span>  ]
 <span id="L291" class="LineNr"> 291 </span>  run [
-<span id="L292" class="LineNr"> 292 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L292" class="LineNr"> 292 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L293" class="LineNr"> 293 </span>  ]
 <span id="L294" class="LineNr"> 294 </span>  screen-should-contain [
-<span id="L295" class="LineNr"> 295 </span>   <span class="Constant"> .          .</span>
-<span id="L296" class="LineNr"> 296 </span>   <span class="Constant"> .3a        .</span>
-<span id="L297" class="LineNr"> 297 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L298" class="LineNr"> 298 </span>   <span class="Constant"> .          .</span>
+<span id="L295" class="LineNr"> 295 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L296" class="LineNr"> 296 </span>  <span class="Conceal">¦</span><span class="Constant"> .3a        .</span>
+<span id="L297" class="LineNr"> 297 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L298" class="LineNr"> 298 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L299" class="LineNr"> 299 </span>  ]
 <span id="L300" class="LineNr"> 300 </span>]
 <span id="L301" class="LineNr"> 301 </span>
@@ -368,56 +369,56 @@ if ('onhashchange' in window) {
 <span id="L307" class="LineNr"> 307 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L308" class="LineNr"> 308 </span>  <span class="Comment"># new line</span>
 <span id="L309" class="LineNr"> 309 </span>  assume-console [
-<span id="L310" class="LineNr"> 310 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 8</span>
-<span id="L311" class="LineNr"> 311 </span>    press enter
+<span id="L310" class="LineNr"> 310 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 8</span>
+<span id="L311" class="LineNr"> 311 </span>  <span class="Conceal">¦</span> press enter
 <span id="L312" class="LineNr"> 312 </span>  ]
 <span id="L313" class="LineNr"> 313 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L314" class="LineNr"> 314 </span>  screen-should-contain [
-<span id="L315" class="LineNr"> 315 </span>   <span class="Constant"> .          .</span>
-<span id="L316" class="LineNr"> 316 </span>   <span class="Constant"> .  abc     .</span>
-<span id="L317" class="LineNr"> 317 </span>   <span class="Constant"> .          .</span>
-<span id="L318" class="LineNr"> 318 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L319" class="LineNr"> 319 </span>   <span class="Constant"> .          .</span>
+<span id="L315" class="LineNr"> 315 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L316" class="LineNr"> 316 </span>  <span class="Conceal">¦</span><span class="Constant"> .  abc     .</span>
+<span id="L317" class="LineNr"> 317 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L318" class="LineNr"> 318 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L319" class="LineNr"> 319 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L320" class="LineNr"> 320 </span>  ]
 <span id="L321" class="LineNr"> 321 </span>  <span class="Comment"># line is indented</span>
 <span id="L322" class="LineNr"> 322 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L323" class="LineNr"> 323 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L324" class="LineNr"> 324 </span>  memory-should-contain [
-<span id="L325" class="LineNr"> 325 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
-<span id="L326" class="LineNr"> 326 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L325" class="LineNr"> 325 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L326" class="LineNr"> 326 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
 <span id="L327" class="LineNr"> 327 </span>  ]
 <span id="L328" class="LineNr"> 328 </span>  <span class="Comment"># undo</span>
 <span id="L329" class="LineNr"> 329 </span>  assume-console [
-<span id="L330" class="LineNr"> 330 </span>    press ctrl-z
+<span id="L330" class="LineNr"> 330 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L331" class="LineNr"> 331 </span>  ]
 <span id="L332" class="LineNr"> 332 </span>  run [
-<span id="L333" class="LineNr"> 333 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L333" class="LineNr"> 333 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L334" class="LineNr"> 334 </span>  ]
 <span id="L335" class="LineNr"> 335 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L336" class="LineNr"> 336 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L337" class="LineNr"> 337 </span>  memory-should-contain [
-<span id="L338" class="LineNr"> 338 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L339" class="LineNr"> 339 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>
+<span id="L338" class="LineNr"> 338 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L339" class="LineNr"> 339 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>
 <span id="L340" class="LineNr"> 340 </span>  ]
 <span id="L341" class="LineNr"> 341 </span>  <span class="Comment"># back to original text</span>
 <span id="L342" class="LineNr"> 342 </span>  screen-should-contain [
-<span id="L343" class="LineNr"> 343 </span>   <span class="Constant"> .          .</span>
-<span id="L344" class="LineNr"> 344 </span>   <span class="Constant"> .  abc     .</span>
-<span id="L345" class="LineNr"> 345 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L346" class="LineNr"> 346 </span>   <span class="Constant"> .          .</span>
+<span id="L343" class="LineNr"> 343 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L344" class="LineNr"> 344 </span>  <span class="Conceal">¦</span><span class="Constant"> .  abc     .</span>
+<span id="L345" class="LineNr"> 345 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L346" class="LineNr"> 346 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L347" class="LineNr"> 347 </span>  ]
 <span id="L348" class="LineNr"> 348 </span>  <span class="Comment"># cursor should be at end of line</span>
 <span id="L349" class="LineNr"> 349 </span>  assume-console [
-<span id="L350" class="LineNr"> 350 </span>    type <span class="Constant">[1]</span>
+<span id="L350" class="LineNr"> 350 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
 <span id="L351" class="LineNr"> 351 </span>  ]
 <span id="L352" class="LineNr"> 352 </span>  run [
-<span id="L353" class="LineNr"> 353 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L353" class="LineNr"> 353 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L354" class="LineNr"> 354 </span>  ]
 <span id="L355" class="LineNr"> 355 </span>  screen-should-contain [
-<span id="L356" class="LineNr"> 356 </span>   <span class="Constant"> .          .</span>
-<span id="L357" class="LineNr"> 357 </span>   <span class="Constant"> .  abc1    .</span>
-<span id="L358" class="LineNr"> 358 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L359" class="LineNr"> 359 </span>   <span class="Constant"> .          .</span>
+<span id="L356" class="LineNr"> 356 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L357" class="LineNr"> 357 </span>  <span class="Conceal">¦</span><span class="Constant"> .  abc1    .</span>
+<span id="L358" class="LineNr"> 358 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L359" class="LineNr"> 359 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L360" class="LineNr"> 360 </span>  ]
 <span id="L361" class="LineNr"> 361 </span>]
 <span id="L362" class="LineNr"> 362 </span>
@@ -430,60 +431,60 @@ if ('onhashchange' in window) {
 <span id="L369" class="LineNr"> 369 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> <span class="Constant">[a]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L370" class="LineNr"> 370 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L371" class="LineNr"> 371 </span>  assume-console [
-<span id="L372" class="LineNr"> 372 </span>    type <span class="Constant">[012]</span>
-<span id="L373" class="LineNr"> 373 </span>    press ctrl-z
+<span id="L372" class="LineNr"> 372 </span>  <span class="Conceal">¦</span> type <span class="Constant">[012]</span>
+<span id="L373" class="LineNr"> 373 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L374" class="LineNr"> 374 </span>  ]
 <span id="L375" class="LineNr"> 375 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L376" class="LineNr"> 376 </span>  screen-should-contain [
-<span id="L377" class="LineNr"> 377 </span>   <span class="Constant"> .          .</span>
-<span id="L378" class="LineNr"> 378 </span>   <span class="Constant"> .a         .</span>
-<span id="L379" class="LineNr"> 379 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L380" class="LineNr"> 380 </span>   <span class="Constant"> .          .</span>
+<span id="L377" class="LineNr"> 377 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L378" class="LineNr"> 378 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L379" class="LineNr"> 379 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L380" class="LineNr"> 380 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L381" class="LineNr"> 381 </span>  ]
 <span id="L382" class="LineNr"> 382 </span>  <span class="Comment"># redo</span>
 <span id="L383" class="LineNr"> 383 </span>  assume-console [
-<span id="L384" class="LineNr"> 384 </span>    press ctrl-y
+<span id="L384" class="LineNr"> 384 </span>  <span class="Conceal">¦</span> press ctrl-y
 <span id="L385" class="LineNr"> 385 </span>  ]
 <span id="L386" class="LineNr"> 386 </span>  run [
-<span id="L387" class="LineNr"> 387 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L387" class="LineNr"> 387 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L388" class="LineNr"> 388 </span>  ]
 <span id="L389" class="LineNr"> 389 </span>  <span class="Comment"># all characters must be back</span>
 <span id="L390" class="LineNr"> 390 </span>  screen-should-contain [
-<span id="L391" class="LineNr"> 391 </span>   <span class="Constant"> .          .</span>
-<span id="L392" class="LineNr"> 392 </span>   <span class="Constant"> .012a      .</span>
-<span id="L393" class="LineNr"> 393 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L394" class="LineNr"> 394 </span>   <span class="Constant"> .          .</span>
+<span id="L391" class="LineNr"> 391 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L392" class="LineNr"> 392 </span>  <span class="Conceal">¦</span><span class="Constant"> .012a      .</span>
+<span id="L393" class="LineNr"> 393 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L394" class="LineNr"> 394 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L395" class="LineNr"> 395 </span>  ]
 <span id="L396" class="LineNr"> 396 </span>  <span class="Comment"># cursor should be in the right place</span>
 <span id="L397" class="LineNr"> 397 </span>  assume-console [
-<span id="L398" class="LineNr"> 398 </span>    type <span class="Constant">[3]</span>
+<span id="L398" class="LineNr"> 398 </span>  <span class="Conceal">¦</span> type <span class="Constant">[3]</span>
 <span id="L399" class="LineNr"> 399 </span>  ]
 <span id="L400" class="LineNr"> 400 </span>  run [
-<span id="L401" class="LineNr"> 401 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L401" class="LineNr"> 401 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L402" class="LineNr"> 402 </span>  ]
 <span id="L403" class="LineNr"> 403 </span>  screen-should-contain [
-<span id="L404" class="LineNr"> 404 </span>   <span class="Constant"> .          .</span>
-<span id="L405" class="LineNr"> 405 </span>   <span class="Constant"> .0123a     .</span>
-<span id="L406" class="LineNr"> 406 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L407" class="LineNr"> 407 </span>   <span class="Constant"> .          .</span>
+<span id="L404" class="LineNr"> 404 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L405" class="LineNr"> 405 </span>  <span class="Conceal">¦</span><span class="Constant"> .0123a     .</span>
+<span id="L406" class="LineNr"> 406 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L407" class="LineNr"> 407 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L408" class="LineNr"> 408 </span>  ]
 <span id="L409" class="LineNr"> 409 </span>]
 <span id="L410" class="LineNr"> 410 </span>
 <span id="L411" class="LineNr"> 411 </span><span class="muRecipe">after</span> <span class="Constant"><a href='012-editor-undo.mu.html#L94'>&lt;handle-redo&gt;</a></span> [
 <span id="L412" class="LineNr"> 412 </span>  <span class="Delimiter">{</span>
-<span id="L413" class="LineNr"> 413 </span>    typing:<a href='012-editor-undo.mu.html#L11'>insert-operation</a>, is-insert?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">typing:variant</span>
-<span id="L414" class="LineNr"> 414 </span>    <span class="muControl">break-unless</span> is-insert?
-<span id="L415" class="LineNr"> 415 </span>    before-cursor <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
-<span id="L416" class="LineNr"> 416 </span>    insert-from:&amp;:duplex-list:char <span class="Special">&lt;-</span> get typing, <span class="Constant">insert-from:offset</span>  <span class="Comment"># ignore insert-to because it's already been spliced away</span>
-<span id="L417" class="LineNr"> 417 </span>    <span class="Comment"># assert insert-to matches next(before-cursor)</span>
-<span id="L418" class="LineNr"> 418 </span>    <a href='../065duplex_list.mu.html#L485'>insert-range</a> before-cursor, insert-from
-<span id="L419" class="LineNr"> 419 </span>    <span class="Comment"># assert cursor-row/cursor-column/top-of-screen match after-row/after-column/after-top-of-screen</span>
-<span id="L420" class="LineNr"> 420 </span>    cursor-row <span class="Special">&lt;-</span> get typing, <span class="Constant">after-row:offset</span>
-<span id="L421" class="LineNr"> 421 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
-<span id="L422" class="LineNr"> 422 </span>    cursor-column <span class="Special">&lt;-</span> get typing, <span class="Constant">after-column:offset</span>
-<span id="L423" class="LineNr"> 423 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
-<span id="L424" class="LineNr"> 424 </span>    top:&amp;:duplex-list:char <span class="Special">&lt;-</span> get typing, <span class="Constant">after-top-of-screen:offset</span>
-<span id="L425" class="LineNr"> 425 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top
+<span id="L413" class="LineNr"> 413 </span>  <span class="Conceal">¦</span> typing:<a href='012-editor-undo.mu.html#L11'>insert-operation</a>, is-insert?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">typing:variant</span>
+<span id="L414" class="LineNr"> 414 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-insert?
+<span id="L415" class="LineNr"> 415 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
+<span id="L416" class="LineNr"> 416 </span>  <span class="Conceal">¦</span> insert-from:&amp;:duplex-list:char <span class="Special">&lt;-</span> get typing, <span class="Constant">insert-from:offset</span>  <span class="Comment"># ignore insert-to because it's already been spliced away</span>
+<span id="L417" class="LineNr"> 417 </span>  <span class="Conceal">¦</span> <span class="Comment"># assert insert-to matches next(before-cursor)</span>
+<span id="L418" class="LineNr"> 418 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L485'>insert-range</a> before-cursor, insert-from
+<span id="L419" class="LineNr"> 419 </span>  <span class="Conceal">¦</span> <span class="Comment"># assert cursor-row/cursor-column/top-of-screen match after-row/after-column/after-top-of-screen</span>
+<span id="L420" class="LineNr"> 420 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> get typing, <span class="Constant">after-row:offset</span>
+<span id="L421" class="LineNr"> 421 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
+<span id="L422" class="LineNr"> 422 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> get typing, <span class="Constant">after-column:offset</span>
+<span id="L423" class="LineNr"> 423 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
+<span id="L424" class="LineNr"> 424 </span>  <span class="Conceal">¦</span> top:&amp;:duplex-list:char <span class="Special">&lt;-</span> get typing, <span class="Constant">after-top-of-screen:offset</span>
+<span id="L425" class="LineNr"> 425 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top
 <span id="L426" class="LineNr"> 426 </span>  <span class="Delimiter">}</span>
 <span id="L427" class="LineNr"> 427 </span>]
 <span id="L428" class="LineNr"> 428 </span>
@@ -494,42 +495,42 @@ if ('onhashchange' in window) {
 <span id="L433" class="LineNr"> 433 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> <span class="Constant">[]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L434" class="LineNr"> 434 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L435" class="LineNr"> 435 </span>  assume-console [
-<span id="L436" class="LineNr"> 436 </span>    type <span class="Constant">[012]</span>
-<span id="L437" class="LineNr"> 437 </span>    press ctrl-z
+<span id="L436" class="LineNr"> 436 </span>  <span class="Conceal">¦</span> type <span class="Constant">[012]</span>
+<span id="L437" class="LineNr"> 437 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L438" class="LineNr"> 438 </span>  ]
 <span id="L439" class="LineNr"> 439 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L440" class="LineNr"> 440 </span>  screen-should-contain [
-<span id="L441" class="LineNr"> 441 </span>   <span class="Constant"> .          .</span>
-<span id="L442" class="LineNr"> 442 </span>   <span class="Constant"> .          .</span>
-<span id="L443" class="LineNr"> 443 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L444" class="LineNr"> 444 </span>   <span class="Constant"> .          .</span>
+<span id="L441" class="LineNr"> 441 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L442" class="LineNr"> 442 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L443" class="LineNr"> 443 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L444" class="LineNr"> 444 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L445" class="LineNr"> 445 </span>  ]
 <span id="L446" class="LineNr"> 446 </span>  <span class="Comment"># redo</span>
 <span id="L447" class="LineNr"> 447 </span>  assume-console [
-<span id="L448" class="LineNr"> 448 </span>    press ctrl-y
+<span id="L448" class="LineNr"> 448 </span>  <span class="Conceal">¦</span> press ctrl-y
 <span id="L449" class="LineNr"> 449 </span>  ]
 <span id="L450" class="LineNr"> 450 </span>  run [
-<span id="L451" class="LineNr"> 451 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L451" class="LineNr"> 451 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L452" class="LineNr"> 452 </span>  ]
 <span id="L453" class="LineNr"> 453 </span>  <span class="Comment"># all characters must be back</span>
 <span id="L454" class="LineNr"> 454 </span>  screen-should-contain [
-<span id="L455" class="LineNr"> 455 </span>   <span class="Constant"> .          .</span>
-<span id="L456" class="LineNr"> 456 </span>   <span class="Constant"> .012       .</span>
-<span id="L457" class="LineNr"> 457 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L458" class="LineNr"> 458 </span>   <span class="Constant"> .          .</span>
+<span id="L455" class="LineNr"> 455 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L456" class="LineNr"> 456 </span>  <span class="Conceal">¦</span><span class="Constant"> .012       .</span>
+<span id="L457" class="LineNr"> 457 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L458" class="LineNr"> 458 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L459" class="LineNr"> 459 </span>  ]
 <span id="L460" class="LineNr"> 460 </span>  <span class="Comment"># cursor should be in the right place</span>
 <span id="L461" class="LineNr"> 461 </span>  assume-console [
-<span id="L462" class="LineNr"> 462 </span>    type <span class="Constant">[3]</span>
+<span id="L462" class="LineNr"> 462 </span>  <span class="Conceal">¦</span> type <span class="Constant">[3]</span>
 <span id="L463" class="LineNr"> 463 </span>  ]
 <span id="L464" class="LineNr"> 464 </span>  run [
-<span id="L465" class="LineNr"> 465 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L465" class="LineNr"> 465 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L466" class="LineNr"> 466 </span>  ]
 <span id="L467" class="LineNr"> 467 </span>  screen-should-contain [
-<span id="L468" class="LineNr"> 468 </span>   <span class="Constant"> .          .</span>
-<span id="L469" class="LineNr"> 469 </span>   <span class="Constant"> .0123      .</span>
-<span id="L470" class="LineNr"> 470 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L471" class="LineNr"> 471 </span>   <span class="Constant"> .          .</span>
+<span id="L468" class="LineNr"> 468 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L469" class="LineNr"> 469 </span>  <span class="Conceal">¦</span><span class="Constant"> .0123      .</span>
+<span id="L470" class="LineNr"> 470 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L471" class="LineNr"> 471 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L472" class="LineNr"> 472 </span>  ]
 <span id="L473" class="LineNr"> 473 </span>]
 <span id="L474" class="LineNr"> 474 </span>
@@ -543,36 +544,36 @@ if ('onhashchange' in window) {
 <span id="L482" class="LineNr"> 482 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> contents, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L483" class="LineNr"> 483 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L484" class="LineNr"> 484 </span>  assume-console [
-<span id="L485" class="LineNr"> 485 </span>    type <span class="Constant">[1]</span>
-<span id="L486" class="LineNr"> 486 </span>    press ctrl-z
+<span id="L485" class="LineNr"> 485 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
+<span id="L486" class="LineNr"> 486 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L487" class="LineNr"> 487 </span>  ]
 <span id="L488" class="LineNr"> 488 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L489" class="LineNr"> 489 </span>  <span class="Comment"># do some more work</span>
 <span id="L490" class="LineNr"> 490 </span>  assume-console [
-<span id="L491" class="LineNr"> 491 </span>    type <span class="Constant">[0]</span>
+<span id="L491" class="LineNr"> 491 </span>  <span class="Conceal">¦</span> type <span class="Constant">[0]</span>
 <span id="L492" class="LineNr"> 492 </span>  ]
 <span id="L493" class="LineNr"> 493 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L494" class="LineNr"> 494 </span>  screen-should-contain [
-<span id="L495" class="LineNr"> 495 </span>   <span class="Constant"> .          .</span>
-<span id="L496" class="LineNr"> 496 </span>   <span class="Constant"> .0abc      .</span>
-<span id="L497" class="LineNr"> 497 </span>   <span class="Constant"> .def       .</span>
-<span id="L498" class="LineNr"> 498 </span>   <span class="Constant"> .ghi       .</span>
-<span id="L499" class="LineNr"> 499 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L495" class="LineNr"> 495 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L496" class="LineNr"> 496 </span>  <span class="Conceal">¦</span><span class="Constant"> .0abc      .</span>
+<span id="L497" class="LineNr"> 497 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
+<span id="L498" class="LineNr"> 498 </span>  <span class="Conceal">¦</span><span class="Constant"> .ghi       .</span>
+<span id="L499" class="LineNr"> 499 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
 <span id="L500" class="LineNr"> 500 </span>  ]
 <span id="L501" class="LineNr"> 501 </span>  <span class="Comment"># redo</span>
 <span id="L502" class="LineNr"> 502 </span>  assume-console [
-<span id="L503" class="LineNr"> 503 </span>    press ctrl-y
+<span id="L503" class="LineNr"> 503 </span>  <span class="Conceal">¦</span> press ctrl-y
 <span id="L504" class="LineNr"> 504 </span>  ]
 <span id="L505" class="LineNr"> 505 </span>  run [
-<span id="L506" class="LineNr"> 506 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L506" class="LineNr"> 506 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L507" class="LineNr"> 507 </span>  ]
 <span id="L508" class="LineNr"> 508 </span>  <span class="Comment"># nothing should happen</span>
 <span id="L509" class="LineNr"> 509 </span>  screen-should-contain [
-<span id="L510" class="LineNr"> 510 </span>   <span class="Constant"> .          .</span>
-<span id="L511" class="LineNr"> 511 </span>   <span class="Constant"> .0abc      .</span>
-<span id="L512" class="LineNr"> 512 </span>   <span class="Constant"> .def       .</span>
-<span id="L513" class="LineNr"> 513 </span>   <span class="Constant"> .ghi       .</span>
-<span id="L514" class="LineNr"> 514 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L510" class="LineNr"> 510 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L511" class="LineNr"> 511 </span>  <span class="Conceal">¦</span><span class="Constant"> .0abc      .</span>
+<span id="L512" class="LineNr"> 512 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
+<span id="L513" class="LineNr"> 513 </span>  <span class="Conceal">¦</span><span class="Constant"> .ghi       .</span>
+<span id="L514" class="LineNr"> 514 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
 <span id="L515" class="LineNr"> 515 </span>  ]
 <span id="L516" class="LineNr"> 516 </span>]
 <span id="L517" class="LineNr"> 517 </span>
@@ -584,150 +585,150 @@ if ('onhashchange' in window) {
 <span id="L523" class="LineNr"> 523 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L524" class="LineNr"> 524 </span>  <span class="Comment"># insert some text and tabs, hit enter, some more text and tabs</span>
 <span id="L525" class="LineNr"> 525 </span>  assume-console [
-<span id="L526" class="LineNr"> 526 </span>    press tab
-<span id="L527" class="LineNr"> 527 </span>    type <span class="Constant">[ab]</span>
-<span id="L528" class="LineNr"> 528 </span>    press tab
-<span id="L529" class="LineNr"> 529 </span>    type <span class="Constant">[cd]</span>
-<span id="L530" class="LineNr"> 530 </span>    press enter
-<span id="L531" class="LineNr"> 531 </span>    press tab
-<span id="L532" class="LineNr"> 532 </span>    type <span class="Constant">[efg]</span>
+<span id="L526" class="LineNr"> 526 </span>  <span class="Conceal">¦</span> press tab
+<span id="L527" class="LineNr"> 527 </span>  <span class="Conceal">¦</span> type <span class="Constant">[ab]</span>
+<span id="L528" class="LineNr"> 528 </span>  <span class="Conceal">¦</span> press tab
+<span id="L529" class="LineNr"> 529 </span>  <span class="Conceal">¦</span> type <span class="Constant">[cd]</span>
+<span id="L530" class="LineNr"> 530 </span>  <span class="Conceal">¦</span> press enter
+<span id="L531" class="LineNr"> 531 </span>  <span class="Conceal">¦</span> press tab
+<span id="L532" class="LineNr"> 532 </span>  <span class="Conceal">¦</span> type <span class="Constant">[efg]</span>
 <span id="L533" class="LineNr"> 533 </span>  ]
 <span id="L534" class="LineNr"> 534 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L535" class="LineNr"> 535 </span>  screen-should-contain [
-<span id="L536" class="LineNr"> 536 </span>   <span class="Constant"> .          .</span>
-<span id="L537" class="LineNr"> 537 </span>   <span class="Constant"> .  ab  cd  .</span>
-<span id="L538" class="LineNr"> 538 </span>   <span class="Constant"> .    efg   .</span>
-<span id="L539" class="LineNr"> 539 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L540" class="LineNr"> 540 </span>   <span class="Constant"> .          .</span>
+<span id="L536" class="LineNr"> 536 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L537" class="LineNr"> 537 </span>  <span class="Conceal">¦</span><span class="Constant"> .  ab  cd  .</span>
+<span id="L538" class="LineNr"> 538 </span>  <span class="Conceal">¦</span><span class="Constant"> .    efg   .</span>
+<span id="L539" class="LineNr"> 539 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L540" class="LineNr"> 540 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L541" class="LineNr"> 541 </span>  ]
 <span id="L542" class="LineNr"> 542 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L543" class="LineNr"> 543 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L544" class="LineNr"> 544 </span>  memory-should-contain [
-<span id="L545" class="LineNr"> 545 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
-<span id="L546" class="LineNr"> 546 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 7</span>
+<span id="L545" class="LineNr"> 545 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L546" class="LineNr"> 546 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 7</span>
 <span id="L547" class="LineNr"> 547 </span>  ]
 <span id="L548" class="LineNr"> 548 </span>  <span class="Comment"># undo</span>
 <span id="L549" class="LineNr"> 549 </span>  assume-console [
-<span id="L550" class="LineNr"> 550 </span>    press ctrl-z
+<span id="L550" class="LineNr"> 550 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L551" class="LineNr"> 551 </span>  ]
 <span id="L552" class="LineNr"> 552 </span>  run [
-<span id="L553" class="LineNr"> 553 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L553" class="LineNr"> 553 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L554" class="LineNr"> 554 </span>  ]
 <span id="L555" class="LineNr"> 555 </span>  <span class="Comment"># typing in second line deleted, but not indent</span>
 <span id="L556" class="LineNr"> 556 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L557" class="LineNr"> 557 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L558" class="LineNr"> 558 </span>  memory-should-contain [
-<span id="L559" class="LineNr"> 559 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
-<span id="L560" class="LineNr"> 560 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L559" class="LineNr"> 559 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L560" class="LineNr"> 560 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
 <span id="L561" class="LineNr"> 561 </span>  ]
 <span id="L562" class="LineNr"> 562 </span>  screen-should-contain [
-<span id="L563" class="LineNr"> 563 </span>   <span class="Constant"> .          .</span>
-<span id="L564" class="LineNr"> 564 </span>   <span class="Constant"> .  ab  cd  .</span>
-<span id="L565" class="LineNr"> 565 </span>   <span class="Constant"> .          .</span>
-<span id="L566" class="LineNr"> 566 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L567" class="LineNr"> 567 </span>   <span class="Constant"> .          .</span>
+<span id="L563" class="LineNr"> 563 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L564" class="LineNr"> 564 </span>  <span class="Conceal">¦</span><span class="Constant"> .  ab  cd  .</span>
+<span id="L565" class="LineNr"> 565 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L566" class="LineNr"> 566 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L567" class="LineNr"> 567 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L568" class="LineNr"> 568 </span>  ]
 <span id="L569" class="LineNr"> 569 </span>  <span class="Comment"># undo again</span>
 <span id="L570" class="LineNr"> 570 </span>  assume-console [
-<span id="L571" class="LineNr"> 571 </span>    press ctrl-z
+<span id="L571" class="LineNr"> 571 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L572" class="LineNr"> 572 </span>  ]
 <span id="L573" class="LineNr"> 573 </span>  run [
-<span id="L574" class="LineNr"> 574 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L574" class="LineNr"> 574 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L575" class="LineNr"> 575 </span>  ]
 <span id="L576" class="LineNr"> 576 </span>  <span class="Comment"># indent and newline deleted</span>
 <span id="L577" class="LineNr"> 577 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L578" class="LineNr"> 578 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L579" class="LineNr"> 579 </span>  memory-should-contain [
-<span id="L580" class="LineNr"> 580 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L581" class="LineNr"> 581 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 8</span>
+<span id="L580" class="LineNr"> 580 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L581" class="LineNr"> 581 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 8</span>
 <span id="L582" class="LineNr"> 582 </span>  ]
 <span id="L583" class="LineNr"> 583 </span>  screen-should-contain [
-<span id="L584" class="LineNr"> 584 </span>   <span class="Constant"> .          .</span>
-<span id="L585" class="LineNr"> 585 </span>   <span class="Constant"> .  ab  cd  .</span>
-<span id="L586" class="LineNr"> 586 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L587" class="LineNr"> 587 </span>   <span class="Constant"> .          .</span>
+<span id="L584" class="LineNr"> 584 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L585" class="LineNr"> 585 </span>  <span class="Conceal">¦</span><span class="Constant"> .  ab  cd  .</span>
+<span id="L586" class="LineNr"> 586 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L587" class="LineNr"> 587 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L588" class="LineNr"> 588 </span>  ]
 <span id="L589" class="LineNr"> 589 </span>  <span class="Comment"># undo again</span>
 <span id="L590" class="LineNr"> 590 </span>  assume-console [
-<span id="L591" class="LineNr"> 591 </span>    press ctrl-z
+<span id="L591" class="LineNr"> 591 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L592" class="LineNr"> 592 </span>  ]
 <span id="L593" class="LineNr"> 593 </span>  run [
-<span id="L594" class="LineNr"> 594 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L594" class="LineNr"> 594 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L595" class="LineNr"> 595 </span>  ]
 <span id="L596" class="LineNr"> 596 </span>  <span class="Comment"># empty screen</span>
 <span id="L597" class="LineNr"> 597 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L598" class="LineNr"> 598 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L599" class="LineNr"> 599 </span>  memory-should-contain [
-<span id="L600" class="LineNr"> 600 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L601" class="LineNr"> 601 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
+<span id="L600" class="LineNr"> 600 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L601" class="LineNr"> 601 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
 <span id="L602" class="LineNr"> 602 </span>  ]
 <span id="L603" class="LineNr"> 603 </span>  screen-should-contain [
-<span id="L604" class="LineNr"> 604 </span>   <span class="Constant"> .          .</span>
-<span id="L605" class="LineNr"> 605 </span>   <span class="Constant"> .          .</span>
-<span id="L606" class="LineNr"> 606 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L607" class="LineNr"> 607 </span>   <span class="Constant"> .          .</span>
+<span id="L604" class="LineNr"> 604 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L605" class="LineNr"> 605 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L606" class="LineNr"> 606 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L607" class="LineNr"> 607 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L608" class="LineNr"> 608 </span>  ]
 <span id="L609" class="LineNr"> 609 </span>  <span class="Comment"># redo</span>
 <span id="L610" class="LineNr"> 610 </span>  assume-console [
-<span id="L611" class="LineNr"> 611 </span>    press ctrl-y
+<span id="L611" class="LineNr"> 611 </span>  <span class="Conceal">¦</span> press ctrl-y
 <span id="L612" class="LineNr"> 612 </span>  ]
 <span id="L613" class="LineNr"> 613 </span>  run [
-<span id="L614" class="LineNr"> 614 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L614" class="LineNr"> 614 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L615" class="LineNr"> 615 </span>  ]
 <span id="L616" class="LineNr"> 616 </span>  <span class="Comment"># first line inserted</span>
 <span id="L617" class="LineNr"> 617 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L618" class="LineNr"> 618 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L619" class="LineNr"> 619 </span>  memory-should-contain [
-<span id="L620" class="LineNr"> 620 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L621" class="LineNr"> 621 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 8</span>
+<span id="L620" class="LineNr"> 620 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L621" class="LineNr"> 621 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 8</span>
 <span id="L622" class="LineNr"> 622 </span>  ]
 <span id="L623" class="LineNr"> 623 </span>  screen-should-contain [
-<span id="L624" class="LineNr"> 624 </span>   <span class="Constant"> .          .</span>
-<span id="L625" class="LineNr"> 625 </span>   <span class="Constant"> .  ab  cd  .</span>
-<span id="L626" class="LineNr"> 626 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L627" class="LineNr"> 627 </span>   <span class="Constant"> .          .</span>
+<span id="L624" class="LineNr"> 624 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L625" class="LineNr"> 625 </span>  <span class="Conceal">¦</span><span class="Constant"> .  ab  cd  .</span>
+<span id="L626" class="LineNr"> 626 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L627" class="LineNr"> 627 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L628" class="LineNr"> 628 </span>  ]
 <span id="L629" class="LineNr"> 629 </span>  <span class="Comment"># redo again</span>
 <span id="L630" class="LineNr"> 630 </span>  assume-console [
-<span id="L631" class="LineNr"> 631 </span>    press ctrl-y
+<span id="L631" class="LineNr"> 631 </span>  <span class="Conceal">¦</span> press ctrl-y
 <span id="L632" class="LineNr"> 632 </span>  ]
 <span id="L633" class="LineNr"> 633 </span>  run [
-<span id="L634" class="LineNr"> 634 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L634" class="LineNr"> 634 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L635" class="LineNr"> 635 </span>  ]
 <span id="L636" class="LineNr"> 636 </span>  <span class="Comment"># newline and indent inserted</span>
 <span id="L637" class="LineNr"> 637 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L638" class="LineNr"> 638 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L639" class="LineNr"> 639 </span>  memory-should-contain [
-<span id="L640" class="LineNr"> 640 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
-<span id="L641" class="LineNr"> 641 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L640" class="LineNr"> 640 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L641" class="LineNr"> 641 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
 <span id="L642" class="LineNr"> 642 </span>  ]
 <span id="L643" class="LineNr"> 643 </span>  screen-should-contain [
-<span id="L644" class="LineNr"> 644 </span>   <span class="Constant"> .          .</span>
-<span id="L645" class="LineNr"> 645 </span>   <span class="Constant"> .  ab  cd  .</span>
-<span id="L646" class="LineNr"> 646 </span>   <span class="Constant"> .          .</span>
-<span id="L647" class="LineNr"> 647 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L648" class="LineNr"> 648 </span>   <span class="Constant"> .          .</span>
+<span id="L644" class="LineNr"> 644 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L645" class="LineNr"> 645 </span>  <span class="Conceal">¦</span><span class="Constant"> .  ab  cd  .</span>
+<span id="L646" class="LineNr"> 646 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L647" class="LineNr"> 647 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L648" class="LineNr"> 648 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L649" class="LineNr"> 649 </span>  ]
 <span id="L650" class="LineNr"> 650 </span>  <span class="Comment"># redo again</span>
 <span id="L651" class="LineNr"> 651 </span>  assume-console [
-<span id="L652" class="LineNr"> 652 </span>    press ctrl-y
+<span id="L652" class="LineNr"> 652 </span>  <span class="Conceal">¦</span> press ctrl-y
 <span id="L653" class="LineNr"> 653 </span>  ]
 <span id="L654" class="LineNr"> 654 </span>  run [
-<span id="L655" class="LineNr"> 655 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L655" class="LineNr"> 655 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L656" class="LineNr"> 656 </span>  ]
 <span id="L657" class="LineNr"> 657 </span>  <span class="Comment"># indent and newline deleted</span>
 <span id="L658" class="LineNr"> 658 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L659" class="LineNr"> 659 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L660" class="LineNr"> 660 </span>  memory-should-contain [
-<span id="L661" class="LineNr"> 661 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
-<span id="L662" class="LineNr"> 662 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 7</span>
+<span id="L661" class="LineNr"> 661 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L662" class="LineNr"> 662 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 7</span>
 <span id="L663" class="LineNr"> 663 </span>  ]
 <span id="L664" class="LineNr"> 664 </span>  screen-should-contain [
-<span id="L665" class="LineNr"> 665 </span>   <span class="Constant"> .          .</span>
-<span id="L666" class="LineNr"> 666 </span>   <span class="Constant"> .  ab  cd  .</span>
-<span id="L667" class="LineNr"> 667 </span>   <span class="Constant"> .    efg   .</span>
-<span id="L668" class="LineNr"> 668 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L669" class="LineNr"> 669 </span>   <span class="Constant"> .          .</span>
+<span id="L665" class="LineNr"> 665 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L666" class="LineNr"> 666 </span>  <span class="Conceal">¦</span><span class="Constant"> .  ab  cd  .</span>
+<span id="L667" class="LineNr"> 667 </span>  <span class="Conceal">¦</span><span class="Constant"> .    efg   .</span>
+<span id="L668" class="LineNr"> 668 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L669" class="LineNr"> 669 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L670" class="LineNr"> 670 </span>  ]
 <span id="L671" class="LineNr"> 671 </span>]
 <span id="L672" class="LineNr"> 672 </span>
@@ -744,36 +745,36 @@ if ('onhashchange' in window) {
 <span id="L683" class="LineNr"> 683 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L684" class="LineNr"> 684 </span>  <span class="Comment"># move the cursor</span>
 <span id="L685" class="LineNr"> 685 </span>  assume-console [
-<span id="L686" class="LineNr"> 686 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 1</span>
+<span id="L686" class="LineNr"> 686 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 1</span>
 <span id="L687" class="LineNr"> 687 </span>  ]
 <span id="L688" class="LineNr"> 688 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L689" class="LineNr"> 689 </span>  <span class="Comment"># undo</span>
 <span id="L690" class="LineNr"> 690 </span>  assume-console [
-<span id="L691" class="LineNr"> 691 </span>    press ctrl-z
+<span id="L691" class="LineNr"> 691 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L692" class="LineNr"> 692 </span>  ]
 <span id="L693" class="LineNr"> 693 </span>  run [
-<span id="L694" class="LineNr"> 694 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L694" class="LineNr"> 694 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L695" class="LineNr"> 695 </span>  ]
 <span id="L696" class="LineNr"> 696 </span>  <span class="Comment"># click undone</span>
 <span id="L697" class="LineNr"> 697 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L698" class="LineNr"> 698 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L699" class="LineNr"> 699 </span>  memory-should-contain [
-<span id="L700" class="LineNr"> 700 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L701" class="LineNr"> 701 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
+<span id="L700" class="LineNr"> 700 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L701" class="LineNr"> 701 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
 <span id="L702" class="LineNr"> 702 </span>  ]
 <span id="L703" class="LineNr"> 703 </span>  <span class="Comment"># cursor should be in the right place</span>
 <span id="L704" class="LineNr"> 704 </span>  assume-console [
-<span id="L705" class="LineNr"> 705 </span>    type <span class="Constant">[1]</span>
+<span id="L705" class="LineNr"> 705 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
 <span id="L706" class="LineNr"> 706 </span>  ]
 <span id="L707" class="LineNr"> 707 </span>  run [
-<span id="L708" class="LineNr"> 708 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L708" class="LineNr"> 708 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L709" class="LineNr"> 709 </span>  ]
 <span id="L710" class="LineNr"> 710 </span>  screen-should-contain [
-<span id="L711" class="LineNr"> 711 </span>   <span class="Constant"> .          .</span>
-<span id="L712" class="LineNr"> 712 </span>   <span class="Constant"> .1abc      .</span>
-<span id="L713" class="LineNr"> 713 </span>   <span class="Constant"> .def       .</span>
-<span id="L714" class="LineNr"> 714 </span>   <span class="Constant"> .ghi       .</span>
-<span id="L715" class="LineNr"> 715 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L711" class="LineNr"> 711 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L712" class="LineNr"> 712 </span>  <span class="Conceal">¦</span><span class="Constant"> .1abc      .</span>
+<span id="L713" class="LineNr"> 713 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
+<span id="L714" class="LineNr"> 714 </span>  <span class="Conceal">¦</span><span class="Constant"> .ghi       .</span>
+<span id="L715" class="LineNr"> 715 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
 <span id="L716" class="LineNr"> 716 </span>  ]
 <span id="L717" class="LineNr"> 717 </span>]
 <span id="L718" class="LineNr"> 718 </span>
@@ -787,22 +788,22 @@ if ('onhashchange' in window) {
 <span id="L726" class="LineNr"> 726 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
 <span id="L727" class="LineNr"> 727 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
 <span id="L728" class="LineNr"> 728 </span>  <span class="Delimiter">{</span>
-<span id="L729" class="LineNr"> 729 </span>    <span class="muControl">break-unless</span> undo-coalesce-tag
-<span id="L730" class="LineNr"> 730 </span>    <span class="Comment"># if previous operation was also a move, and also had the same coalesce</span>
-<span id="L731" class="LineNr"> 731 </span>    <span class="Comment"># tag, coalesce with it</span>
-<span id="L732" class="LineNr"> 732 </span>    undo:&amp;:list:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">undo:offset</span>
-<span id="L733" class="LineNr"> 733 </span>    <span class="muControl">break-unless</span> undo
-<span id="L734" class="LineNr"> 734 </span>    op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> first undo
-<span id="L735" class="LineNr"> 735 </span>    move:<a href='012-editor-undo.mu.html#L26'>move-operation</a>, is-move?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">move:variant</span>
-<span id="L736" class="LineNr"> 736 </span>    <span class="muControl">break-unless</span> is-move?
-<span id="L737" class="LineNr"> 737 </span>    previous-coalesce-tag:num <span class="Special">&lt;-</span> get move, <span class="Constant">tag:offset</span>
-<span id="L738" class="LineNr"> 738 </span>    coalesce?:bool <span class="Special">&lt;-</span> equal undo-coalesce-tag, previous-coalesce-tag
-<span id="L739" class="LineNr"> 739 </span>    <span class="muControl">break-unless</span> coalesce?
-<span id="L740" class="LineNr"> 740 </span>    move <span class="Special">&lt;-</span> put move, <span class="Constant">after-row:offset</span>, cursor-row
-<span id="L741" class="LineNr"> 741 </span>    move <span class="Special">&lt;-</span> put move, <span class="Constant">after-column:offset</span>, cursor-column
-<span id="L742" class="LineNr"> 742 </span>    move <span class="Special">&lt;-</span> put move, <span class="Constant">after-top-of-screen:offset</span>, top-after
-<span id="L743" class="LineNr"> 743 </span>    *op <span class="Special">&lt;-</span> merge <span class="Constant">1/move-operation</span>, move
-<span id="L744" class="LineNr"> 744 </span>    <span class="muControl">break</span> <span class="Constant">+done-adding-move-operation</span>
+<span id="L729" class="LineNr"> 729 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> undo-coalesce-tag
+<span id="L730" class="LineNr"> 730 </span>  <span class="Conceal">¦</span> <span class="Comment"># if previous operation was also a move, and also had the same coalesce</span>
+<span id="L731" class="LineNr"> 731 </span>  <span class="Conceal">¦</span> <span class="Comment"># tag, coalesce with it</span>
+<span id="L732" class="LineNr"> 732 </span>  <span class="Conceal">¦</span> undo:&amp;:list:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">undo:offset</span>
+<span id="L733" class="LineNr"> 733 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> undo
+<span id="L734" class="LineNr"> 734 </span>  <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> first undo
+<span id="L735" class="LineNr"> 735 </span>  <span class="Conceal">¦</span> move:<a href='012-editor-undo.mu.html#L26'>move-operation</a>, is-move?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">move:variant</span>
+<span id="L736" class="LineNr"> 736 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-move?
+<span id="L737" class="LineNr"> 737 </span>  <span class="Conceal">¦</span> previous-coalesce-tag:num <span class="Special">&lt;-</span> get move, <span class="Constant">tag:offset</span>
+<span id="L738" class="LineNr"> 738 </span>  <span class="Conceal">¦</span> coalesce?:bool <span class="Special">&lt;-</span> equal undo-coalesce-tag, previous-coalesce-tag
+<span id="L739" class="LineNr"> 739 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> coalesce?
+<span id="L740" class="LineNr"> 740 </span>  <span class="Conceal">¦</span> move <span class="Special">&lt;-</span> put move, <span class="Constant">after-row:offset</span>, cursor-row
+<span id="L741" class="LineNr"> 741 </span>  <span class="Conceal">¦</span> move <span class="Special">&lt;-</span> put move, <span class="Constant">after-column:offset</span>, cursor-column
+<span id="L742" class="LineNr"> 742 </span>  <span class="Conceal">¦</span> move <span class="Special">&lt;-</span> put move, <span class="Constant">after-top-of-screen:offset</span>, top-after
+<span id="L743" class="LineNr"> 743 </span>  <span class="Conceal">¦</span> *op <span class="Special">&lt;-</span> merge <span class="Constant">1/move-operation</span>, move
+<span id="L744" class="LineNr"> 744 </span>  <span class="Conceal">¦</span> <span class="muControl">break</span> <span class="Constant">+done-adding-move-operation</span>
 <span id="L745" class="LineNr"> 745 </span>  <span class="Delimiter">}</span>
 <span id="L746" class="LineNr"> 746 </span>  op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> new <span class="Constant"><a href='012-editor-undo.mu.html#L5'>operation</a>:type</span>
 <span id="L747" class="LineNr"> 747 </span>  *op <span class="Special">&lt;-</span> merge <span class="Constant">1/move-operation</span>, cursor-row-before, cursor-column-before, top-before, cursor-row/after, cursor-column/after, top-after, undo-coalesce-tag
@@ -812,15 +813,15 @@ if ('onhashchange' in window) {
 <span id="L751" class="LineNr"> 751 </span>
 <span id="L752" class="LineNr"> 752 </span><span class="muRecipe">after</span> <span class="Constant"><a href='012-editor-undo.mu.html#L76'>&lt;handle-undo&gt;</a></span> [
 <span id="L753" class="LineNr"> 753 </span>  <span class="Delimiter">{</span>
-<span id="L754" class="LineNr"> 754 </span>    move:<a href='012-editor-undo.mu.html#L26'>move-operation</a>, is-move?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">move:variant</span>
-<span id="L755" class="LineNr"> 755 </span>    <span class="muControl">break-unless</span> is-move?
-<span id="L756" class="LineNr"> 756 </span>    <span class="Comment"># assert cursor-row/cursor-column/top-of-screen match after-row/after-column/after-top-of-screen</span>
-<span id="L757" class="LineNr"> 757 </span>    cursor-row <span class="Special">&lt;-</span> get move, <span class="Constant">before-row:offset</span>
-<span id="L758" class="LineNr"> 758 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
-<span id="L759" class="LineNr"> 759 </span>    cursor-column <span class="Special">&lt;-</span> get move, <span class="Constant">before-column:offset</span>
-<span id="L760" class="LineNr"> 760 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
-<span id="L761" class="LineNr"> 761 </span>    top:&amp;:duplex-list:char <span class="Special">&lt;-</span> get move, <span class="Constant">before-top-of-screen:offset</span>
-<span id="L762" class="LineNr"> 762 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top
+<span id="L754" class="LineNr"> 754 </span>  <span class="Conceal">¦</span> move:<a href='012-editor-undo.mu.html#L26'>move-operation</a>, is-move?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">move:variant</span>
+<span id="L755" class="LineNr"> 755 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-move?
+<span id="L756" class="LineNr"> 756 </span>  <span class="Conceal">¦</span> <span class="Comment"># assert cursor-row/cursor-column/top-of-screen match after-row/after-column/after-top-of-screen</span>
+<span id="L757" class="LineNr"> 757 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> get move, <span class="Constant">before-row:offset</span>
+<span id="L758" class="LineNr"> 758 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
+<span id="L759" class="LineNr"> 759 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> get move, <span class="Constant">before-column:offset</span>
+<span id="L760" class="LineNr"> 760 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
+<span id="L761" class="LineNr"> 761 </span>  <span class="Conceal">¦</span> top:&amp;:duplex-list:char <span class="Special">&lt;-</span> get move, <span class="Constant">before-top-of-screen:offset</span>
+<span id="L762" class="LineNr"> 762 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top
 <span id="L763" class="LineNr"> 763 </span>  <span class="Delimiter">}</span>
 <span id="L764" class="LineNr"> 764 </span>]
 <span id="L765" class="LineNr"> 765 </span>
@@ -835,56 +836,56 @@ if ('onhashchange' in window) {
 <span id="L774" class="LineNr"> 774 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> contents, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
 <span id="L775" class="LineNr"> 775 </span>  <span class="Comment"># position cursor at end of screen and try to move right</span>
 <span id="L776" class="LineNr"> 776 </span>  assume-console [
-<span id="L777" class="LineNr"> 777 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 3</span>
-<span id="L778" class="LineNr"> 778 </span>    press right-arrow
+<span id="L777" class="LineNr"> 777 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 3</span>
+<span id="L778" class="LineNr"> 778 </span>  <span class="Conceal">¦</span> press right-arrow
 <span id="L779" class="LineNr"> 779 </span>  ]
 <span id="L780" class="LineNr"> 780 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L781" class="LineNr"> 781 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L782" class="LineNr"> 782 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L783" class="LineNr"> 783 </span>  <span class="Comment"># screen scrolls</span>
 <span id="L784" class="LineNr"> 784 </span>  screen-should-contain [
-<span id="L785" class="LineNr"> 785 </span>   <span class="Constant"> .     .</span>
-<span id="L786" class="LineNr"> 786 </span>   <span class="Constant"> .b    .</span>
-<span id="L787" class="LineNr"> 787 </span><span class="Constant">    .cdef↩.</span>
-<span id="L788" class="LineNr"> 788 </span>   <span class="Constant"> .gh   .</span>
+<span id="L785" class="LineNr"> 785 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L786" class="LineNr"> 786 </span>  <span class="Conceal">¦</span><span class="Constant"> .b    .</span>
+<span id="L787" class="LineNr"> 787 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .cdef↩.</span>
+<span id="L788" class="LineNr"> 788 </span>  <span class="Conceal">¦</span><span class="Constant"> .gh   .</span>
 <span id="L789" class="LineNr"> 789 </span>  ]
 <span id="L790" class="LineNr"> 790 </span>  memory-should-contain [
-<span id="L791" class="LineNr"> 791 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
-<span id="L792" class="LineNr"> 792 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
+<span id="L791" class="LineNr"> 791 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L792" class="LineNr"> 792 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
 <span id="L793" class="LineNr"> 793 </span>  ]
 <span id="L794" class="LineNr"> 794 </span>  <span class="Comment"># undo</span>
 <span id="L795" class="LineNr"> 795 </span>  assume-console [
-<span id="L796" class="LineNr"> 796 </span>    press ctrl-z
+<span id="L796" class="LineNr"> 796 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L797" class="LineNr"> 797 </span>  ]
 <span id="L798" class="LineNr"> 798 </span>  run [
-<span id="L799" class="LineNr"> 799 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L799" class="LineNr"> 799 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L800" class="LineNr"> 800 </span>  ]
 <span id="L801" class="LineNr"> 801 </span>  <span class="Comment"># cursor moved back</span>
 <span id="L802" class="LineNr"> 802 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L803" class="LineNr"> 803 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L804" class="LineNr"> 804 </span>  memory-should-contain [
-<span id="L805" class="LineNr"> 805 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
-<span id="L806" class="LineNr"> 806 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L805" class="LineNr"> 805 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L806" class="LineNr"> 806 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
 <span id="L807" class="LineNr"> 807 </span>  ]
 <span id="L808" class="LineNr"> 808 </span>  <span class="Comment"># scroll undone</span>
 <span id="L809" class="LineNr"> 809 </span>  screen-should-contain [
-<span id="L810" class="LineNr"> 810 </span>   <span class="Constant"> .     .</span>
-<span id="L811" class="LineNr"> 811 </span>   <span class="Constant"> .a    .</span>
-<span id="L812" class="LineNr"> 812 </span>   <span class="Constant"> .b    .</span>
-<span id="L813" class="LineNr"> 813 </span><span class="Constant">    .cdef↩.</span>
+<span id="L810" class="LineNr"> 810 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L811" class="LineNr"> 811 </span>  <span class="Conceal">¦</span><span class="Constant"> .a    .</span>
+<span id="L812" class="LineNr"> 812 </span>  <span class="Conceal">¦</span><span class="Constant"> .b    .</span>
+<span id="L813" class="LineNr"> 813 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .cdef↩.</span>
 <span id="L814" class="LineNr"> 814 </span>  ]
 <span id="L815" class="LineNr"> 815 </span>  <span class="Comment"># cursor should be in the right place</span>
 <span id="L816" class="LineNr"> 816 </span>  assume-console [
-<span id="L817" class="LineNr"> 817 </span>    type <span class="Constant">[1]</span>
+<span id="L817" class="LineNr"> 817 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
 <span id="L818" class="LineNr"> 818 </span>  ]
 <span id="L819" class="LineNr"> 819 </span>  run [
-<span id="L820" class="LineNr"> 820 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L820" class="LineNr"> 820 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L821" class="LineNr"> 821 </span>  ]
 <span id="L822" class="LineNr"> 822 </span>  screen-should-contain [
-<span id="L823" class="LineNr"> 823 </span>   <span class="Constant"> .     .</span>
-<span id="L824" class="LineNr"> 824 </span>   <span class="Constant"> .b    .</span>
-<span id="L825" class="LineNr"> 825 </span><span class="Constant">    .cde1↩.</span>
-<span id="L826" class="LineNr"> 826 </span>   <span class="Constant"> .fgh  .</span>
+<span id="L823" class="LineNr"> 823 </span>  <span class="Conceal">¦</span><span class="Constant"> .     .</span>
+<span id="L824" class="LineNr"> 824 </span>  <span class="Conceal">¦</span><span class="Constant"> .b    .</span>
+<span id="L825" class="LineNr"> 825 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .cde1↩.</span>
+<span id="L826" class="LineNr"> 826 </span>  <span class="Conceal">¦</span><span class="Constant"> .fgh  .</span>
 <span id="L827" class="LineNr"> 827 </span>  ]
 <span id="L828" class="LineNr"> 828 </span>]
 <span id="L829" class="LineNr"> 829 </span>
@@ -899,37 +900,37 @@ if ('onhashchange' in window) {
 <span id="L838" class="LineNr"> 838 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L839" class="LineNr"> 839 </span>  <span class="Comment"># move the cursor</span>
 <span id="L840" class="LineNr"> 840 </span>  assume-console [
-<span id="L841" class="LineNr"> 841 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 1</span>
-<span id="L842" class="LineNr"> 842 </span>    press left-arrow
+<span id="L841" class="LineNr"> 841 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 1</span>
+<span id="L842" class="LineNr"> 842 </span>  <span class="Conceal">¦</span> press left-arrow
 <span id="L843" class="LineNr"> 843 </span>  ]
 <span id="L844" class="LineNr"> 844 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L845" class="LineNr"> 845 </span>  <span class="Comment"># undo</span>
 <span id="L846" class="LineNr"> 846 </span>  assume-console [
-<span id="L847" class="LineNr"> 847 </span>    press ctrl-z
+<span id="L847" class="LineNr"> 847 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L848" class="LineNr"> 848 </span>  ]
 <span id="L849" class="LineNr"> 849 </span>  run [
-<span id="L850" class="LineNr"> 850 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L850" class="LineNr"> 850 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L851" class="LineNr"> 851 </span>  ]
 <span id="L852" class="LineNr"> 852 </span>  <span class="Comment"># cursor moves back</span>
 <span id="L853" class="LineNr"> 853 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L854" class="LineNr"> 854 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L855" class="LineNr"> 855 </span>  memory-should-contain [
-<span id="L856" class="LineNr"> 856 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
-<span id="L857" class="LineNr"> 857 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L856" class="LineNr"> 856 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L857" class="LineNr"> 857 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L858" class="LineNr"> 858 </span>  ]
 <span id="L859" class="LineNr"> 859 </span>  <span class="Comment"># cursor should be in the right place</span>
 <span id="L860" class="LineNr"> 860 </span>  assume-console [
-<span id="L861" class="LineNr"> 861 </span>    type <span class="Constant">[1]</span>
+<span id="L861" class="LineNr"> 861 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
 <span id="L862" class="LineNr"> 862 </span>  ]
 <span id="L863" class="LineNr"> 863 </span>  run [
-<span id="L864" class="LineNr"> 864 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L864" class="LineNr"> 864 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L865" class="LineNr"> 865 </span>  ]
 <span id="L866" class="LineNr"> 866 </span>  screen-should-contain [
-<span id="L867" class="LineNr"> 867 </span>   <span class="Constant"> .          .</span>
-<span id="L868" class="LineNr"> 868 </span>   <span class="Constant"> .abc       .</span>
-<span id="L869" class="LineNr"> 869 </span>   <span class="Constant"> .def       .</span>
-<span id="L870" class="LineNr"> 870 </span>   <span class="Constant"> .g1hi      .</span>
-<span id="L871" class="LineNr"> 871 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L867" class="LineNr"> 867 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L868" class="LineNr"> 868 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L869" class="LineNr"> 869 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
+<span id="L870" class="LineNr"> 870 </span>  <span class="Conceal">¦</span><span class="Constant"> .g1hi      .</span>
+<span id="L871" class="LineNr"> 871 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
 <span id="L872" class="LineNr"> 872 </span>  ]
 <span id="L873" class="LineNr"> 873 </span>]
 <span id="L874" class="LineNr"> 874 </span>
@@ -944,43 +945,43 @@ if ('onhashchange' in window) {
 <span id="L883" class="LineNr"> 883 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L884" class="LineNr"> 884 </span>  <span class="Comment"># move the cursor</span>
 <span id="L885" class="LineNr"> 885 </span>  assume-console [
-<span id="L886" class="LineNr"> 886 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 1</span>
-<span id="L887" class="LineNr"> 887 </span>    press up-arrow
+<span id="L886" class="LineNr"> 886 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 1</span>
+<span id="L887" class="LineNr"> 887 </span>  <span class="Conceal">¦</span> press up-arrow
 <span id="L888" class="LineNr"> 888 </span>  ]
 <span id="L889" class="LineNr"> 889 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L890" class="LineNr"> 890 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L891" class="LineNr"> 891 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L892" class="LineNr"> 892 </span>  memory-should-contain [
-<span id="L893" class="LineNr"> 893 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
-<span id="L894" class="LineNr"> 894 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L893" class="LineNr"> 893 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L894" class="LineNr"> 894 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L895" class="LineNr"> 895 </span>  ]
 <span id="L896" class="LineNr"> 896 </span>  <span class="Comment"># undo</span>
 <span id="L897" class="LineNr"> 897 </span>  assume-console [
-<span id="L898" class="LineNr"> 898 </span>    press ctrl-z
+<span id="L898" class="LineNr"> 898 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L899" class="LineNr"> 899 </span>  ]
 <span id="L900" class="LineNr"> 900 </span>  run [
-<span id="L901" class="LineNr"> 901 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L901" class="LineNr"> 901 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L902" class="LineNr"> 902 </span>  ]
 <span id="L903" class="LineNr"> 903 </span>  <span class="Comment"># cursor moves back</span>
 <span id="L904" class="LineNr"> 904 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L905" class="LineNr"> 905 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L906" class="LineNr"> 906 </span>  memory-should-contain [
-<span id="L907" class="LineNr"> 907 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
-<span id="L908" class="LineNr"> 908 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L907" class="LineNr"> 907 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L908" class="LineNr"> 908 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L909" class="LineNr"> 909 </span>  ]
 <span id="L910" class="LineNr"> 910 </span>  <span class="Comment"># cursor should be in the right place</span>
 <span id="L911" class="LineNr"> 911 </span>  assume-console [
-<span id="L912" class="LineNr"> 912 </span>    type <span class="Constant">[1]</span>
+<span id="L912" class="LineNr"> 912 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
 <span id="L913" class="LineNr"> 913 </span>  ]
 <span id="L914" class="LineNr"> 914 </span>  run [
-<span id="L915" class="LineNr"> 915 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L915" class="LineNr"> 915 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L916" class="LineNr"> 916 </span>  ]
 <span id="L917" class="LineNr"> 917 </span>  screen-should-contain [
-<span id="L918" class="LineNr"> 918 </span>   <span class="Constant"> .          .</span>
-<span id="L919" class="LineNr"> 919 </span>   <span class="Constant"> .abc       .</span>
-<span id="L920" class="LineNr"> 920 </span>   <span class="Constant"> .def       .</span>
-<span id="L921" class="LineNr"> 921 </span>   <span class="Constant"> .g1hi      .</span>
-<span id="L922" class="LineNr"> 922 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L918" class="LineNr"> 918 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L919" class="LineNr"> 919 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L920" class="LineNr"> 920 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
+<span id="L921" class="LineNr"> 921 </span>  <span class="Conceal">¦</span><span class="Constant"> .g1hi      .</span>
+<span id="L922" class="LineNr"> 922 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
 <span id="L923" class="LineNr"> 923 </span>  ]
 <span id="L924" class="LineNr"> 924 </span>]
 <span id="L925" class="LineNr"> 925 </span>
@@ -995,37 +996,37 @@ if ('onhashchange' in window) {
 <span id="L934" class="LineNr"> 934 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L935" class="LineNr"> 935 </span>  <span class="Comment"># move the cursor</span>
 <span id="L936" class="LineNr"> 936 </span>  assume-console [
-<span id="L937" class="LineNr"> 937 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
-<span id="L938" class="LineNr"> 938 </span>    press down-arrow
+<span id="L937" class="LineNr"> 937 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
+<span id="L938" class="LineNr"> 938 </span>  <span class="Conceal">¦</span> press down-arrow
 <span id="L939" class="LineNr"> 939 </span>  ]
 <span id="L940" class="LineNr"> 940 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L941" class="LineNr"> 941 </span>  <span class="Comment"># undo</span>
 <span id="L942" class="LineNr"> 942 </span>  assume-console [
-<span id="L943" class="LineNr"> 943 </span>    press ctrl-z
+<span id="L943" class="LineNr"> 943 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L944" class="LineNr"> 944 </span>  ]
 <span id="L945" class="LineNr"> 945 </span>  run [
-<span id="L946" class="LineNr"> 946 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L946" class="LineNr"> 946 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L947" class="LineNr"> 947 </span>  ]
 <span id="L948" class="LineNr"> 948 </span>  <span class="Comment"># cursor moves back</span>
 <span id="L949" class="LineNr"> 949 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L950" class="LineNr"> 950 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L951" class="LineNr"> 951 </span>  memory-should-contain [
-<span id="L952" class="LineNr"> 952 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
-<span id="L953" class="LineNr"> 953 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L952" class="LineNr"> 952 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L953" class="LineNr"> 953 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L954" class="LineNr"> 954 </span>  ]
 <span id="L955" class="LineNr"> 955 </span>  <span class="Comment"># cursor should be in the right place</span>
 <span id="L956" class="LineNr"> 956 </span>  assume-console [
-<span id="L957" class="LineNr"> 957 </span>    type <span class="Constant">[1]</span>
+<span id="L957" class="LineNr"> 957 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
 <span id="L958" class="LineNr"> 958 </span>  ]
 <span id="L959" class="LineNr"> 959 </span>  run [
-<span id="L960" class="LineNr"> 960 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L960" class="LineNr"> 960 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L961" class="LineNr"> 961 </span>  ]
 <span id="L962" class="LineNr"> 962 </span>  screen-should-contain [
-<span id="L963" class="LineNr"> 963 </span>   <span class="Constant"> .          .</span>
-<span id="L964" class="LineNr"> 964 </span>   <span class="Constant"> .abc       .</span>
-<span id="L965" class="LineNr"> 965 </span>   <span class="Constant"> .d1ef      .</span>
-<span id="L966" class="LineNr"> 966 </span>   <span class="Constant"> .ghi       .</span>
-<span id="L967" class="LineNr"> 967 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L963" class="LineNr"> 963 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L964" class="LineNr"> 964 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L965" class="LineNr"> 965 </span>  <span class="Conceal">¦</span><span class="Constant"> .d1ef      .</span>
+<span id="L966" class="LineNr"> 966 </span>  <span class="Conceal">¦</span><span class="Constant"> .ghi       .</span>
+<span id="L967" class="LineNr"> 967 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
 <span id="L968" class="LineNr"> 968 </span>  ]
 <span id="L969" class="LineNr"> 969 </span>]
 <span id="L970" class="LineNr"> 970 </span>
@@ -1043,23 +1044,23 @@ if ('onhashchange' in window) {
 <span id="L982" class="LineNr"> 982 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L983" class="LineNr"> 983 </span>  <span class="Comment"># scroll the page</span>
 <span id="L984" class="LineNr"> 984 </span>  assume-console [
-<span id="L985" class="LineNr"> 985 </span>    press ctrl-f
+<span id="L985" class="LineNr"> 985 </span>  <span class="Conceal">¦</span> press ctrl-f
 <span id="L986" class="LineNr"> 986 </span>  ]
 <span id="L987" class="LineNr"> 987 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L988" class="LineNr"> 988 </span>  <span class="Comment"># undo</span>
 <span id="L989" class="LineNr"> 989 </span>  assume-console [
-<span id="L990" class="LineNr"> 990 </span>    press ctrl-z
+<span id="L990" class="LineNr"> 990 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L991" class="LineNr"> 991 </span>  ]
 <span id="L992" class="LineNr"> 992 </span>  run [
-<span id="L993" class="LineNr"> 993 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L993" class="LineNr"> 993 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L994" class="LineNr"> 994 </span>  ]
 <span id="L995" class="LineNr"> 995 </span>  <span class="Comment"># screen should again show page 1</span>
 <span id="L996" class="LineNr"> 996 </span>  screen-should-contain [
-<span id="L997" class="LineNr"> 997 </span>   <span class="Constant"> .          .</span>
-<span id="L998" class="LineNr"> 998 </span>   <span class="Constant"> .a         .</span>
-<span id="L999" class="LineNr"> 999 </span>   <span class="Constant"> .b         .</span>
-<span id="L1000" class="LineNr">1000 </span>   <span class="Constant"> .c         .</span>
-<span id="L1001" class="LineNr">1001 </span>   <span class="Constant"> .d         .</span>
+<span id="L997" class="LineNr"> 997 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L998" class="LineNr"> 998 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L999" class="LineNr"> 999 </span>  <span class="Conceal">¦</span><span class="Constant"> .b         .</span>
+<span id="L1000" class="LineNr">1000 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
+<span id="L1001" class="LineNr">1001 </span>  <span class="Conceal">¦</span><span class="Constant"> .d         .</span>
 <span id="L1002" class="LineNr">1002 </span>  ]
 <span id="L1003" class="LineNr">1003 </span>]
 <span id="L1004" class="LineNr">1004 </span>
@@ -1077,23 +1078,23 @@ if ('onhashchange' in window) {
 <span id="L1016" class="LineNr">1016 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L1017" class="LineNr">1017 </span>  <span class="Comment"># scroll the page</span>
 <span id="L1018" class="LineNr">1018 </span>  assume-console [
-<span id="L1019" class="LineNr">1019 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L1019" class="LineNr">1019 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
 <span id="L1020" class="LineNr">1020 </span>  ]
 <span id="L1021" class="LineNr">1021 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1022" class="LineNr">1022 </span>  <span class="Comment"># undo</span>
 <span id="L1023" class="LineNr">1023 </span>  assume-console [
-<span id="L1024" class="LineNr">1024 </span>    press ctrl-z
+<span id="L1024" class="LineNr">1024 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L1025" class="LineNr">1025 </span>  ]
 <span id="L1026" class="LineNr">1026 </span>  run [
-<span id="L1027" class="LineNr">1027 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1027" class="LineNr">1027 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1028" class="LineNr">1028 </span>  ]
 <span id="L1029" class="LineNr">1029 </span>  <span class="Comment"># screen should again show page 1</span>
 <span id="L1030" class="LineNr">1030 </span>  screen-should-contain [
-<span id="L1031" class="LineNr">1031 </span>   <span class="Constant"> .          .</span>
-<span id="L1032" class="LineNr">1032 </span>   <span class="Constant"> .a         .</span>
-<span id="L1033" class="LineNr">1033 </span>   <span class="Constant"> .b         .</span>
-<span id="L1034" class="LineNr">1034 </span>   <span class="Constant"> .c         .</span>
-<span id="L1035" class="LineNr">1035 </span>   <span class="Constant"> .d         .</span>
+<span id="L1031" class="LineNr">1031 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1032" class="LineNr">1032 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L1033" class="LineNr">1033 </span>  <span class="Conceal">¦</span><span class="Constant"> .b         .</span>
+<span id="L1034" class="LineNr">1034 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
+<span id="L1035" class="LineNr">1035 </span>  <span class="Conceal">¦</span><span class="Constant"> .d         .</span>
 <span id="L1036" class="LineNr">1036 </span>  ]
 <span id="L1037" class="LineNr">1037 </span>]
 <span id="L1038" class="LineNr">1038 </span>
@@ -1111,24 +1112,24 @@ if ('onhashchange' in window) {
 <span id="L1050" class="LineNr">1050 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L1051" class="LineNr">1051 </span>  <span class="Comment"># scroll the page down and up</span>
 <span id="L1052" class="LineNr">1052 </span>  assume-console [
-<span id="L1053" class="LineNr">1053 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
-<span id="L1054" class="LineNr">1054 </span>    press ctrl-b
+<span id="L1053" class="LineNr">1053 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L1054" class="LineNr">1054 </span>  <span class="Conceal">¦</span> press ctrl-b
 <span id="L1055" class="LineNr">1055 </span>  ]
 <span id="L1056" class="LineNr">1056 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1057" class="LineNr">1057 </span>  <span class="Comment"># undo</span>
 <span id="L1058" class="LineNr">1058 </span>  assume-console [
-<span id="L1059" class="LineNr">1059 </span>    press ctrl-z
+<span id="L1059" class="LineNr">1059 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L1060" class="LineNr">1060 </span>  ]
 <span id="L1061" class="LineNr">1061 </span>  run [
-<span id="L1062" class="LineNr">1062 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1062" class="LineNr">1062 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1063" class="LineNr">1063 </span>  ]
 <span id="L1064" class="LineNr">1064 </span>  <span class="Comment"># screen should again show page 2</span>
 <span id="L1065" class="LineNr">1065 </span>  screen-should-contain [
-<span id="L1066" class="LineNr">1066 </span>   <span class="Constant"> .          .</span>
-<span id="L1067" class="LineNr">1067 </span>   <span class="Constant"> .d         .</span>
-<span id="L1068" class="LineNr">1068 </span>   <span class="Constant"> .e         .</span>
-<span id="L1069" class="LineNr">1069 </span>   <span class="Constant"> .f         .</span>
-<span id="L1070" class="LineNr">1070 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1066" class="LineNr">1066 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1067" class="LineNr">1067 </span>  <span class="Conceal">¦</span><span class="Constant"> .d         .</span>
+<span id="L1068" class="LineNr">1068 </span>  <span class="Conceal">¦</span><span class="Constant"> .e         .</span>
+<span id="L1069" class="LineNr">1069 </span>  <span class="Conceal">¦</span><span class="Constant"> .f         .</span>
+<span id="L1070" class="LineNr">1070 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
 <span id="L1071" class="LineNr">1071 </span>  ]
 <span id="L1072" class="LineNr">1072 </span>]
 <span id="L1073" class="LineNr">1073 </span>
@@ -1146,24 +1147,24 @@ if ('onhashchange' in window) {
 <span id="L1085" class="LineNr">1085 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L1086" class="LineNr">1086 </span>  <span class="Comment"># scroll the page down and up</span>
 <span id="L1087" class="LineNr">1087 </span>  assume-console [
-<span id="L1088" class="LineNr">1088 </span>    press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
-<span id="L1089" class="LineNr">1089 </span>    press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
+<span id="L1088" class="LineNr">1088 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2789'>page-down</a>
+<span id="L1089" class="LineNr">1089 </span>  <span class="Conceal">¦</span> press <a href='003-shortcuts.mu.html#L2987'>page-up</a>
 <span id="L1090" class="LineNr">1090 </span>  ]
 <span id="L1091" class="LineNr">1091 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1092" class="LineNr">1092 </span>  <span class="Comment"># undo</span>
 <span id="L1093" class="LineNr">1093 </span>  assume-console [
-<span id="L1094" class="LineNr">1094 </span>    press ctrl-z
+<span id="L1094" class="LineNr">1094 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L1095" class="LineNr">1095 </span>  ]
 <span id="L1096" class="LineNr">1096 </span>  run [
-<span id="L1097" class="LineNr">1097 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1097" class="LineNr">1097 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1098" class="LineNr">1098 </span>  ]
 <span id="L1099" class="LineNr">1099 </span>  <span class="Comment"># screen should again show page 2</span>
 <span id="L1100" class="LineNr">1100 </span>  screen-should-contain [
-<span id="L1101" class="LineNr">1101 </span>   <span class="Constant"> .          .</span>
-<span id="L1102" class="LineNr">1102 </span>   <span class="Constant"> .d         .</span>
-<span id="L1103" class="LineNr">1103 </span>   <span class="Constant"> .e         .</span>
-<span id="L1104" class="LineNr">1104 </span>   <span class="Constant"> .f         .</span>
-<span id="L1105" class="LineNr">1105 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1101" class="LineNr">1101 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1102" class="LineNr">1102 </span>  <span class="Conceal">¦</span><span class="Constant"> .d         .</span>
+<span id="L1103" class="LineNr">1103 </span>  <span class="Conceal">¦</span><span class="Constant"> .e         .</span>
+<span id="L1104" class="LineNr">1104 </span>  <span class="Conceal">¦</span><span class="Constant"> .f         .</span>
+<span id="L1105" class="LineNr">1105 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
 <span id="L1106" class="LineNr">1106 </span>  ]
 <span id="L1107" class="LineNr">1107 </span>]
 <span id="L1108" class="LineNr">1108 </span>
@@ -1178,37 +1179,37 @@ if ('onhashchange' in window) {
 <span id="L1117" class="LineNr">1117 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L1118" class="LineNr">1118 </span>  <span class="Comment"># move the cursor, then to start of line</span>
 <span id="L1119" class="LineNr">1119 </span>  assume-console [
-<span id="L1120" class="LineNr">1120 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
-<span id="L1121" class="LineNr">1121 </span>    press ctrl-a
+<span id="L1120" class="LineNr">1120 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
+<span id="L1121" class="LineNr">1121 </span>  <span class="Conceal">¦</span> press ctrl-a
 <span id="L1122" class="LineNr">1122 </span>  ]
 <span id="L1123" class="LineNr">1123 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1124" class="LineNr">1124 </span>  <span class="Comment"># undo</span>
 <span id="L1125" class="LineNr">1125 </span>  assume-console [
-<span id="L1126" class="LineNr">1126 </span>    press ctrl-z
+<span id="L1126" class="LineNr">1126 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L1127" class="LineNr">1127 </span>  ]
 <span id="L1128" class="LineNr">1128 </span>  run [
-<span id="L1129" class="LineNr">1129 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1129" class="LineNr">1129 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1130" class="LineNr">1130 </span>  ]
 <span id="L1131" class="LineNr">1131 </span>  <span class="Comment"># cursor moves back</span>
 <span id="L1132" class="LineNr">1132 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L1133" class="LineNr">1133 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1134" class="LineNr">1134 </span>  memory-should-contain [
-<span id="L1135" class="LineNr">1135 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
-<span id="L1136" class="LineNr">1136 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1135" class="LineNr">1135 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L1136" class="LineNr">1136 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L1137" class="LineNr">1137 </span>  ]
 <span id="L1138" class="LineNr">1138 </span>  <span class="Comment"># cursor should be in the right place</span>
 <span id="L1139" class="LineNr">1139 </span>  assume-console [
-<span id="L1140" class="LineNr">1140 </span>    type <span class="Constant">[1]</span>
+<span id="L1140" class="LineNr">1140 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
 <span id="L1141" class="LineNr">1141 </span>  ]
 <span id="L1142" class="LineNr">1142 </span>  run [
-<span id="L1143" class="LineNr">1143 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1143" class="LineNr">1143 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1144" class="LineNr">1144 </span>  ]
 <span id="L1145" class="LineNr">1145 </span>  screen-should-contain [
-<span id="L1146" class="LineNr">1146 </span>   <span class="Constant"> .          .</span>
-<span id="L1147" class="LineNr">1147 </span>   <span class="Constant"> .abc       .</span>
-<span id="L1148" class="LineNr">1148 </span>   <span class="Constant"> .d1ef      .</span>
-<span id="L1149" class="LineNr">1149 </span>   <span class="Constant"> .ghi       .</span>
-<span id="L1150" class="LineNr">1150 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1146" class="LineNr">1146 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1147" class="LineNr">1147 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L1148" class="LineNr">1148 </span>  <span class="Conceal">¦</span><span class="Constant"> .d1ef      .</span>
+<span id="L1149" class="LineNr">1149 </span>  <span class="Conceal">¦</span><span class="Constant"> .ghi       .</span>
+<span id="L1150" class="LineNr">1150 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
 <span id="L1151" class="LineNr">1151 </span>  ]
 <span id="L1152" class="LineNr">1152 </span>]
 <span id="L1153" class="LineNr">1153 </span>
@@ -1223,37 +1224,37 @@ if ('onhashchange' in window) {
 <span id="L1162" class="LineNr">1162 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L1163" class="LineNr">1163 </span>  <span class="Comment"># move the cursor, then to start of line</span>
 <span id="L1164" class="LineNr">1164 </span>  assume-console [
-<span id="L1165" class="LineNr">1165 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
-<span id="L1166" class="LineNr">1166 </span>    press home
+<span id="L1165" class="LineNr">1165 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
+<span id="L1166" class="LineNr">1166 </span>  <span class="Conceal">¦</span> press home
 <span id="L1167" class="LineNr">1167 </span>  ]
 <span id="L1168" class="LineNr">1168 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1169" class="LineNr">1169 </span>  <span class="Comment"># undo</span>
 <span id="L1170" class="LineNr">1170 </span>  assume-console [
-<span id="L1171" class="LineNr">1171 </span>    press ctrl-z
+<span id="L1171" class="LineNr">1171 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L1172" class="LineNr">1172 </span>  ]
 <span id="L1173" class="LineNr">1173 </span>  run [
-<span id="L1174" class="LineNr">1174 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1174" class="LineNr">1174 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1175" class="LineNr">1175 </span>  ]
 <span id="L1176" class="LineNr">1176 </span>  <span class="Comment"># cursor moves back</span>
 <span id="L1177" class="LineNr">1177 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L1178" class="LineNr">1178 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1179" class="LineNr">1179 </span>  memory-should-contain [
-<span id="L1180" class="LineNr">1180 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
-<span id="L1181" class="LineNr">1181 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1180" class="LineNr">1180 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L1181" class="LineNr">1181 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L1182" class="LineNr">1182 </span>  ]
 <span id="L1183" class="LineNr">1183 </span>  <span class="Comment"># cursor should be in the right place</span>
 <span id="L1184" class="LineNr">1184 </span>  assume-console [
-<span id="L1185" class="LineNr">1185 </span>    type <span class="Constant">[1]</span>
+<span id="L1185" class="LineNr">1185 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
 <span id="L1186" class="LineNr">1186 </span>  ]
 <span id="L1187" class="LineNr">1187 </span>  run [
-<span id="L1188" class="LineNr">1188 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1188" class="LineNr">1188 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1189" class="LineNr">1189 </span>  ]
 <span id="L1190" class="LineNr">1190 </span>  screen-should-contain [
-<span id="L1191" class="LineNr">1191 </span>   <span class="Constant"> .          .</span>
-<span id="L1192" class="LineNr">1192 </span>   <span class="Constant"> .abc       .</span>
-<span id="L1193" class="LineNr">1193 </span>   <span class="Constant"> .d1ef      .</span>
-<span id="L1194" class="LineNr">1194 </span>   <span class="Constant"> .ghi       .</span>
-<span id="L1195" class="LineNr">1195 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1191" class="LineNr">1191 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1192" class="LineNr">1192 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L1193" class="LineNr">1193 </span>  <span class="Conceal">¦</span><span class="Constant"> .d1ef      .</span>
+<span id="L1194" class="LineNr">1194 </span>  <span class="Conceal">¦</span><span class="Constant"> .ghi       .</span>
+<span id="L1195" class="LineNr">1195 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
 <span id="L1196" class="LineNr">1196 </span>  ]
 <span id="L1197" class="LineNr">1197 </span>]
 <span id="L1198" class="LineNr">1198 </span>
@@ -1268,37 +1269,37 @@ if ('onhashchange' in window) {
 <span id="L1207" class="LineNr">1207 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L1208" class="LineNr">1208 </span>  <span class="Comment"># move the cursor, then to start of line</span>
 <span id="L1209" class="LineNr">1209 </span>  assume-console [
-<span id="L1210" class="LineNr">1210 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
-<span id="L1211" class="LineNr">1211 </span>    press ctrl-e
+<span id="L1210" class="LineNr">1210 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
+<span id="L1211" class="LineNr">1211 </span>  <span class="Conceal">¦</span> press ctrl-e
 <span id="L1212" class="LineNr">1212 </span>  ]
 <span id="L1213" class="LineNr">1213 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1214" class="LineNr">1214 </span>  <span class="Comment"># undo</span>
 <span id="L1215" class="LineNr">1215 </span>  assume-console [
-<span id="L1216" class="LineNr">1216 </span>    press ctrl-z
+<span id="L1216" class="LineNr">1216 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L1217" class="LineNr">1217 </span>  ]
 <span id="L1218" class="LineNr">1218 </span>  run [
-<span id="L1219" class="LineNr">1219 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1219" class="LineNr">1219 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1220" class="LineNr">1220 </span>  ]
 <span id="L1221" class="LineNr">1221 </span>  <span class="Comment"># cursor moves back</span>
 <span id="L1222" class="LineNr">1222 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L1223" class="LineNr">1223 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1224" class="LineNr">1224 </span>  memory-should-contain [
-<span id="L1225" class="LineNr">1225 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
-<span id="L1226" class="LineNr">1226 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1225" class="LineNr">1225 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L1226" class="LineNr">1226 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L1227" class="LineNr">1227 </span>  ]
 <span id="L1228" class="LineNr">1228 </span>  <span class="Comment"># cursor should be in the right place</span>
 <span id="L1229" class="LineNr">1229 </span>  assume-console [
-<span id="L1230" class="LineNr">1230 </span>    type <span class="Constant">[1]</span>
+<span id="L1230" class="LineNr">1230 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
 <span id="L1231" class="LineNr">1231 </span>  ]
 <span id="L1232" class="LineNr">1232 </span>  run [
-<span id="L1233" class="LineNr">1233 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1233" class="LineNr">1233 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1234" class="LineNr">1234 </span>  ]
 <span id="L1235" class="LineNr">1235 </span>  screen-should-contain [
-<span id="L1236" class="LineNr">1236 </span>   <span class="Constant"> .          .</span>
-<span id="L1237" class="LineNr">1237 </span>   <span class="Constant"> .abc       .</span>
-<span id="L1238" class="LineNr">1238 </span>   <span class="Constant"> .d1ef      .</span>
-<span id="L1239" class="LineNr">1239 </span>   <span class="Constant"> .ghi       .</span>
-<span id="L1240" class="LineNr">1240 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1236" class="LineNr">1236 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1237" class="LineNr">1237 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L1238" class="LineNr">1238 </span>  <span class="Conceal">¦</span><span class="Constant"> .d1ef      .</span>
+<span id="L1239" class="LineNr">1239 </span>  <span class="Conceal">¦</span><span class="Constant"> .ghi       .</span>
+<span id="L1240" class="LineNr">1240 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
 <span id="L1241" class="LineNr">1241 </span>  ]
 <span id="L1242" class="LineNr">1242 </span>]
 <span id="L1243" class="LineNr">1243 </span>
@@ -1313,37 +1314,37 @@ if ('onhashchange' in window) {
 <span id="L1252" class="LineNr">1252 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L1253" class="LineNr">1253 </span>  <span class="Comment"># move the cursor, then to start of line</span>
 <span id="L1254" class="LineNr">1254 </span>  assume-console [
-<span id="L1255" class="LineNr">1255 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
-<span id="L1256" class="LineNr">1256 </span>    press end
+<span id="L1255" class="LineNr">1255 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
+<span id="L1256" class="LineNr">1256 </span>  <span class="Conceal">¦</span> press end
 <span id="L1257" class="LineNr">1257 </span>  ]
 <span id="L1258" class="LineNr">1258 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1259" class="LineNr">1259 </span>  <span class="Comment"># undo</span>
 <span id="L1260" class="LineNr">1260 </span>  assume-console [
-<span id="L1261" class="LineNr">1261 </span>    press ctrl-z
+<span id="L1261" class="LineNr">1261 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L1262" class="LineNr">1262 </span>  ]
 <span id="L1263" class="LineNr">1263 </span>  run [
-<span id="L1264" class="LineNr">1264 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1264" class="LineNr">1264 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1265" class="LineNr">1265 </span>  ]
 <span id="L1266" class="LineNr">1266 </span>  <span class="Comment"># cursor moves back</span>
 <span id="L1267" class="LineNr">1267 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L1268" class="LineNr">1268 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1269" class="LineNr">1269 </span>  memory-should-contain [
-<span id="L1270" class="LineNr">1270 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
-<span id="L1271" class="LineNr">1271 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1270" class="LineNr">1270 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L1271" class="LineNr">1271 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L1272" class="LineNr">1272 </span>  ]
 <span id="L1273" class="LineNr">1273 </span>  <span class="Comment"># cursor should be in the right place</span>
 <span id="L1274" class="LineNr">1274 </span>  assume-console [
-<span id="L1275" class="LineNr">1275 </span>    type <span class="Constant">[1]</span>
+<span id="L1275" class="LineNr">1275 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
 <span id="L1276" class="LineNr">1276 </span>  ]
 <span id="L1277" class="LineNr">1277 </span>  run [
-<span id="L1278" class="LineNr">1278 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1278" class="LineNr">1278 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1279" class="LineNr">1279 </span>  ]
 <span id="L1280" class="LineNr">1280 </span>  screen-should-contain [
-<span id="L1281" class="LineNr">1281 </span>   <span class="Constant"> .          .</span>
-<span id="L1282" class="LineNr">1282 </span>   <span class="Constant"> .abc       .</span>
-<span id="L1283" class="LineNr">1283 </span>   <span class="Constant"> .d1ef      .</span>
-<span id="L1284" class="LineNr">1284 </span>   <span class="Constant"> .ghi       .</span>
-<span id="L1285" class="LineNr">1285 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1281" class="LineNr">1281 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1282" class="LineNr">1282 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L1283" class="LineNr">1283 </span>  <span class="Conceal">¦</span><span class="Constant"> .d1ef      .</span>
+<span id="L1284" class="LineNr">1284 </span>  <span class="Conceal">¦</span><span class="Constant"> .ghi       .</span>
+<span id="L1285" class="LineNr">1285 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
 <span id="L1286" class="LineNr">1286 </span>  ]
 <span id="L1287" class="LineNr">1287 </span>]
 <span id="L1288" class="LineNr">1288 </span>
@@ -1358,45 +1359,45 @@ if ('onhashchange' in window) {
 <span id="L1297" class="LineNr">1297 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L1298" class="LineNr">1298 </span>  <span class="Comment"># move the cursor</span>
 <span id="L1299" class="LineNr">1299 </span>  assume-console [
-<span id="L1300" class="LineNr">1300 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
-<span id="L1301" class="LineNr">1301 </span>    press right-arrow
-<span id="L1302" class="LineNr">1302 </span>    press right-arrow
-<span id="L1303" class="LineNr">1303 </span>    press up-arrow
+<span id="L1300" class="LineNr">1300 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
+<span id="L1301" class="LineNr">1301 </span>  <span class="Conceal">¦</span> press right-arrow
+<span id="L1302" class="LineNr">1302 </span>  <span class="Conceal">¦</span> press right-arrow
+<span id="L1303" class="LineNr">1303 </span>  <span class="Conceal">¦</span> press up-arrow
 <span id="L1304" class="LineNr">1304 </span>  ]
 <span id="L1305" class="LineNr">1305 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1306" class="LineNr">1306 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L1307" class="LineNr">1307 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1308" class="LineNr">1308 </span>  memory-should-contain [
-<span id="L1309" class="LineNr">1309 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1310" class="LineNr">1310 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L1309" class="LineNr">1309 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1310" class="LineNr">1310 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
 <span id="L1311" class="LineNr">1311 </span>  ]
 <span id="L1312" class="LineNr">1312 </span>  <span class="Comment"># undo</span>
 <span id="L1313" class="LineNr">1313 </span>  assume-console [
-<span id="L1314" class="LineNr">1314 </span>    press ctrl-z
+<span id="L1314" class="LineNr">1314 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L1315" class="LineNr">1315 </span>  ]
 <span id="L1316" class="LineNr">1316 </span>  run [
-<span id="L1317" class="LineNr">1317 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1317" class="LineNr">1317 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1318" class="LineNr">1318 </span>  ]
 <span id="L1319" class="LineNr">1319 </span>  <span class="Comment"># up-arrow is undone</span>
 <span id="L1320" class="LineNr">1320 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L1321" class="LineNr">1321 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1322" class="LineNr">1322 </span>  memory-should-contain [
-<span id="L1323" class="LineNr">1323 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
-<span id="L1324" class="LineNr">1324 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L1323" class="LineNr">1323 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L1324" class="LineNr">1324 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
 <span id="L1325" class="LineNr">1325 </span>  ]
 <span id="L1326" class="LineNr">1326 </span>  <span class="Comment"># undo again</span>
 <span id="L1327" class="LineNr">1327 </span>  assume-console [
-<span id="L1328" class="LineNr">1328 </span>    press ctrl-z
+<span id="L1328" class="LineNr">1328 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L1329" class="LineNr">1329 </span>  ]
 <span id="L1330" class="LineNr">1330 </span>  run [
-<span id="L1331" class="LineNr">1331 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1331" class="LineNr">1331 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1332" class="LineNr">1332 </span>  ]
 <span id="L1333" class="LineNr">1333 </span>  <span class="Comment"># both right-arrows are undone</span>
 <span id="L1334" class="LineNr">1334 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L1335" class="LineNr">1335 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1336" class="LineNr">1336 </span>  memory-should-contain [
-<span id="L1337" class="LineNr">1337 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
-<span id="L1338" class="LineNr">1338 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1337" class="LineNr">1337 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L1338" class="LineNr">1338 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L1339" class="LineNr">1339 </span>  ]
 <span id="L1340" class="LineNr">1340 </span>]
 <span id="L1341" class="LineNr">1341 </span>
@@ -1412,51 +1413,51 @@ if ('onhashchange' in window) {
 <span id="L1351" class="LineNr">1351 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> contents, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L1352" class="LineNr">1352 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L1353" class="LineNr">1353 </span>  assume-console [
-<span id="L1354" class="LineNr">1354 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 1</span>
-<span id="L1355" class="LineNr">1355 </span>    press ctrl-z
+<span id="L1354" class="LineNr">1354 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 3</span>,<span class="Constant"> 1</span>
+<span id="L1355" class="LineNr">1355 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L1356" class="LineNr">1356 </span>  ]
 <span id="L1357" class="LineNr">1357 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1358" class="LineNr">1358 </span>  <span class="Comment"># redo</span>
 <span id="L1359" class="LineNr">1359 </span>  assume-console [
-<span id="L1360" class="LineNr">1360 </span>    press ctrl-y
+<span id="L1360" class="LineNr">1360 </span>  <span class="Conceal">¦</span> press ctrl-y
 <span id="L1361" class="LineNr">1361 </span>  ]
 <span id="L1362" class="LineNr">1362 </span>  run [
-<span id="L1363" class="LineNr">1363 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1363" class="LineNr">1363 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1364" class="LineNr">1364 </span>  ]
 <span id="L1365" class="LineNr">1365 </span>  <span class="Comment"># cursor moves to left-click</span>
 <span id="L1366" class="LineNr">1366 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L1367" class="LineNr">1367 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1368" class="LineNr">1368 </span>  memory-should-contain [
-<span id="L1369" class="LineNr">1369 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
-<span id="L1370" class="LineNr">1370 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1369" class="LineNr">1369 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L1370" class="LineNr">1370 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L1371" class="LineNr">1371 </span>  ]
 <span id="L1372" class="LineNr">1372 </span>  <span class="Comment"># cursor should be in the right place</span>
 <span id="L1373" class="LineNr">1373 </span>  assume-console [
-<span id="L1374" class="LineNr">1374 </span>    type <span class="Constant">[1]</span>
+<span id="L1374" class="LineNr">1374 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
 <span id="L1375" class="LineNr">1375 </span>  ]
 <span id="L1376" class="LineNr">1376 </span>  run [
-<span id="L1377" class="LineNr">1377 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1377" class="LineNr">1377 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1378" class="LineNr">1378 </span>  ]
 <span id="L1379" class="LineNr">1379 </span>  screen-should-contain [
-<span id="L1380" class="LineNr">1380 </span>   <span class="Constant"> .          .</span>
-<span id="L1381" class="LineNr">1381 </span>   <span class="Constant"> .abc       .</span>
-<span id="L1382" class="LineNr">1382 </span>   <span class="Constant"> .def       .</span>
-<span id="L1383" class="LineNr">1383 </span>   <span class="Constant"> .g1hi      .</span>
-<span id="L1384" class="LineNr">1384 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1380" class="LineNr">1380 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1381" class="LineNr">1381 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L1382" class="LineNr">1382 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
+<span id="L1383" class="LineNr">1383 </span>  <span class="Conceal">¦</span><span class="Constant"> .g1hi      .</span>
+<span id="L1384" class="LineNr">1384 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
 <span id="L1385" class="LineNr">1385 </span>  ]
 <span id="L1386" class="LineNr">1386 </span>]
 <span id="L1387" class="LineNr">1387 </span>
 <span id="L1388" class="LineNr">1388 </span><span class="muRecipe">after</span> <span class="Constant"><a href='012-editor-undo.mu.html#L94'>&lt;handle-redo&gt;</a></span> [
 <span id="L1389" class="LineNr">1389 </span>  <span class="Delimiter">{</span>
-<span id="L1390" class="LineNr">1390 </span>    move:<a href='012-editor-undo.mu.html#L26'>move-operation</a>, is-move?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">move:variant</span>
-<span id="L1391" class="LineNr">1391 </span>    <span class="muControl">break-unless</span> is-move?
-<span id="L1392" class="LineNr">1392 </span>    <span class="Comment"># assert cursor-row/cursor-column/top-of-screen match after-row/after-column/after-top-of-screen</span>
-<span id="L1393" class="LineNr">1393 </span>    cursor-row <span class="Special">&lt;-</span> get move, <span class="Constant">after-row:offset</span>
-<span id="L1394" class="LineNr">1394 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
-<span id="L1395" class="LineNr">1395 </span>    cursor-column <span class="Special">&lt;-</span> get move, <span class="Constant">after-column:offset</span>
-<span id="L1396" class="LineNr">1396 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
-<span id="L1397" class="LineNr">1397 </span>    top:&amp;:duplex-list:char <span class="Special">&lt;-</span> get move, <span class="Constant">after-top-of-screen:offset</span>
-<span id="L1398" class="LineNr">1398 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top
+<span id="L1390" class="LineNr">1390 </span>  <span class="Conceal">¦</span> move:<a href='012-editor-undo.mu.html#L26'>move-operation</a>, is-move?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">move:variant</span>
+<span id="L1391" class="LineNr">1391 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-move?
+<span id="L1392" class="LineNr">1392 </span>  <span class="Conceal">¦</span> <span class="Comment"># assert cursor-row/cursor-column/top-of-screen match after-row/after-column/after-top-of-screen</span>
+<span id="L1393" class="LineNr">1393 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> get move, <span class="Constant">after-row:offset</span>
+<span id="L1394" class="LineNr">1394 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
+<span id="L1395" class="LineNr">1395 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> get move, <span class="Constant">after-column:offset</span>
+<span id="L1396" class="LineNr">1396 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
+<span id="L1397" class="LineNr">1397 </span>  <span class="Conceal">¦</span> top:&amp;:duplex-list:char <span class="Special">&lt;-</span> get move, <span class="Constant">after-top-of-screen:offset</span>
+<span id="L1398" class="LineNr">1398 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top
 <span id="L1399" class="LineNr">1399 </span>  <span class="Delimiter">}</span>
 <span id="L1400" class="LineNr">1400 </span>]
 <span id="L1401" class="LineNr">1401 </span>
@@ -1467,143 +1468,143 @@ if ('onhashchange' in window) {
 <span id="L1406" class="LineNr">1406 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L52'>new-editor</a> <span class="Constant">[]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
 <span id="L1407" class="LineNr">1407 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L1408" class="LineNr">1408 </span>  assume-console [
-<span id="L1409" class="LineNr">1409 </span>    type <span class="Constant">[abc]</span>
-<span id="L1410" class="LineNr">1410 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
-<span id="L1411" class="LineNr">1411 </span>    type <span class="Constant">[d]</span>
+<span id="L1409" class="LineNr">1409 </span>  <span class="Conceal">¦</span> type <span class="Constant">[abc]</span>
+<span id="L1410" class="LineNr">1410 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
+<span id="L1411" class="LineNr">1411 </span>  <span class="Conceal">¦</span> type <span class="Constant">[d]</span>
 <span id="L1412" class="LineNr">1412 </span>  ]
 <span id="L1413" class="LineNr">1413 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1414" class="LineNr">1414 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L1415" class="LineNr">1415 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1416" class="LineNr">1416 </span>  screen-should-contain [
-<span id="L1417" class="LineNr">1417 </span>   <span class="Constant"> .          .</span>
-<span id="L1418" class="LineNr">1418 </span>   <span class="Constant"> .adbc      .</span>
-<span id="L1419" class="LineNr">1419 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1420" class="LineNr">1420 </span>   <span class="Constant"> .          .</span>
+<span id="L1417" class="LineNr">1417 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1418" class="LineNr">1418 </span>  <span class="Conceal">¦</span><span class="Constant"> .adbc      .</span>
+<span id="L1419" class="LineNr">1419 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1420" class="LineNr">1420 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1421" class="LineNr">1421 </span>  ]
 <span id="L1422" class="LineNr">1422 </span>  memory-should-contain [
-<span id="L1423" class="LineNr">1423 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1424" class="LineNr">1424 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L1423" class="LineNr">1423 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1424" class="LineNr">1424 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
 <span id="L1425" class="LineNr">1425 </span>  ]
 <span id="L1426" class="LineNr">1426 </span>  <span class="Comment"># undo</span>
 <span id="L1427" class="LineNr">1427 </span>  assume-console [
-<span id="L1428" class="LineNr">1428 </span>    press ctrl-z
+<span id="L1428" class="LineNr">1428 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L1429" class="LineNr">1429 </span>  ]
 <span id="L1430" class="LineNr">1430 </span>  run [
-<span id="L1431" class="LineNr">1431 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L1432" class="LineNr">1432 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L1433" class="LineNr">1433 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L1431" class="LineNr">1431 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1432" class="LineNr">1432 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L1433" class="LineNr">1433 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1434" class="LineNr">1434 </span>  ]
 <span id="L1435" class="LineNr">1435 </span>  <span class="Comment"># last letter typed is deleted</span>
 <span id="L1436" class="LineNr">1436 </span>  screen-should-contain [
-<span id="L1437" class="LineNr">1437 </span>   <span class="Constant"> .          .</span>
-<span id="L1438" class="LineNr">1438 </span>   <span class="Constant"> .abc       .</span>
-<span id="L1439" class="LineNr">1439 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1440" class="LineNr">1440 </span>   <span class="Constant"> .          .</span>
+<span id="L1437" class="LineNr">1437 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1438" class="LineNr">1438 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L1439" class="LineNr">1439 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1440" class="LineNr">1440 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1441" class="LineNr">1441 </span>  ]
 <span id="L1442" class="LineNr">1442 </span>  memory-should-contain [
-<span id="L1443" class="LineNr">1443 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1444" class="LineNr">1444 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1443" class="LineNr">1443 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1444" class="LineNr">1444 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L1445" class="LineNr">1445 </span>  ]
 <span id="L1446" class="LineNr">1446 </span>  <span class="Comment"># undo again</span>
 <span id="L1447" class="LineNr">1447 </span>  assume-console [
-<span id="L1448" class="LineNr">1448 </span>    press ctrl-z
+<span id="L1448" class="LineNr">1448 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L1449" class="LineNr">1449 </span>  ]
 <span id="L1450" class="LineNr">1450 </span>  run [
-<span id="L1451" class="LineNr">1451 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L1452" class="LineNr">1452 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L1453" class="LineNr">1453 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L1451" class="LineNr">1451 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1452" class="LineNr">1452 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L1453" class="LineNr">1453 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1454" class="LineNr">1454 </span>  ]
 <span id="L1455" class="LineNr">1455 </span>  <span class="Comment"># no change to screen; cursor moves</span>
 <span id="L1456" class="LineNr">1456 </span>  screen-should-contain [
-<span id="L1457" class="LineNr">1457 </span>   <span class="Constant"> .          .</span>
-<span id="L1458" class="LineNr">1458 </span>   <span class="Constant"> .abc       .</span>
-<span id="L1459" class="LineNr">1459 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1460" class="LineNr">1460 </span>   <span class="Constant"> .          .</span>
+<span id="L1457" class="LineNr">1457 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1458" class="LineNr">1458 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L1459" class="LineNr">1459 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1460" class="LineNr">1460 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1461" class="LineNr">1461 </span>  ]
 <span id="L1462" class="LineNr">1462 </span>  memory-should-contain [
-<span id="L1463" class="LineNr">1463 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1464" class="LineNr">1464 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L1463" class="LineNr">1463 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1464" class="LineNr">1464 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
 <span id="L1465" class="LineNr">1465 </span>  ]
 <span id="L1466" class="LineNr">1466 </span>  <span class="Comment"># undo again</span>
 <span id="L1467" class="LineNr">1467 </span>  assume-console [
-<span id="L1468" class="LineNr">1468 </span>    press ctrl-z
+<span id="L1468" class="LineNr">1468 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L1469" class="LineNr">1469 </span>  ]
 <span id="L1470" class="LineNr">1470 </span>  run [
-<span id="L1471" class="LineNr">1471 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L1472" class="LineNr">1472 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L1473" class="LineNr">1473 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L1471" class="LineNr">1471 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1472" class="LineNr">1472 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L1473" class="LineNr">1473 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1474" class="LineNr">1474 </span>  ]
 <span id="L1475" class="LineNr">1475 </span>  <span class="Comment"># screen empty</span>
 <span id="L1476" class="LineNr">1476 </span>  screen-should-contain [
-<span id="L1477" class="LineNr">1477 </span>   <span class="Constant"> .          .</span>
-<span id="L1478" class="LineNr">1478 </span>   <span class="Constant"> .          .</span>
-<span id="L1479" class="LineNr">1479 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1480" class="LineNr">1480 </span>   <span class="Constant"> .          .</span>
+<span id="L1477" class="LineNr">1477 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1478" class="LineNr">1478 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1479" class="LineNr">1479 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1480" class="LineNr">1480 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1481" class="LineNr">1481 </span>  ]
 <span id="L1482" class="LineNr">1482 </span>  memory-should-contain [
-<span id="L1483" class="LineNr">1483 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1484" class="LineNr">1484 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
+<span id="L1483" class="LineNr">1483 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1484" class="LineNr">1484 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
 <span id="L1485" class="LineNr">1485 </span>  ]
 <span id="L1486" class="LineNr">1486 </span>  <span class="Comment"># redo</span>
 <span id="L1487" class="LineNr">1487 </span>  assume-console [
-<span id="L1488" class="LineNr">1488 </span>    press ctrl-y
+<span id="L1488" class="LineNr">1488 </span>  <span class="Conceal">¦</span> press ctrl-y
 <span id="L1489" class="LineNr">1489 </span>  ]
 <span id="L1490" class="LineNr">1490 </span>  run [
-<span id="L1491" class="LineNr">1491 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L1492" class="LineNr">1492 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L1493" class="LineNr">1493 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L1491" class="LineNr">1491 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1492" class="LineNr">1492 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L1493" class="LineNr">1493 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1494" class="LineNr">1494 </span>  ]
 <span id="L1495" class="LineNr">1495 </span>  <span class="Comment"># first insert</span>
 <span id="L1496" class="LineNr">1496 </span>  screen-should-contain [
-<span id="L1497" class="LineNr">1497 </span>   <span class="Constant"> .          .</span>
-<span id="L1498" class="LineNr">1498 </span>   <span class="Constant"> .abc       .</span>
-<span id="L1499" class="LineNr">1499 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1500" class="LineNr">1500 </span>   <span class="Constant"> .          .</span>
+<span id="L1497" class="LineNr">1497 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1498" class="LineNr">1498 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L1499" class="LineNr">1499 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1500" class="LineNr">1500 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1501" class="LineNr">1501 </span>  ]
 <span id="L1502" class="LineNr">1502 </span>  memory-should-contain [
-<span id="L1503" class="LineNr">1503 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1504" class="LineNr">1504 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L1503" class="LineNr">1503 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1504" class="LineNr">1504 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
 <span id="L1505" class="LineNr">1505 </span>  ]
 <span id="L1506" class="LineNr">1506 </span>  <span class="Comment"># redo again</span>
 <span id="L1507" class="LineNr">1507 </span>  assume-console [
-<span id="L1508" class="LineNr">1508 </span>    press ctrl-y
+<span id="L1508" class="LineNr">1508 </span>  <span class="Conceal">¦</span> press ctrl-y
 <span id="L1509" class="LineNr">1509 </span>  ]
 <span id="L1510" class="LineNr">1510 </span>  run [
-<span id="L1511" class="LineNr">1511 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L1512" class="LineNr">1512 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L1513" class="LineNr">1513 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L1511" class="LineNr">1511 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1512" class="LineNr">1512 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L1513" class="LineNr">1513 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1514" class="LineNr">1514 </span>  ]
 <span id="L1515" class="LineNr">1515 </span>  <span class="Comment"># cursor moves</span>
 <span id="L1516" class="LineNr">1516 </span>  screen-should-contain [
-<span id="L1517" class="LineNr">1517 </span>   <span class="Constant"> .          .</span>
-<span id="L1518" class="LineNr">1518 </span>   <span class="Constant"> .abc       .</span>
-<span id="L1519" class="LineNr">1519 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1520" class="LineNr">1520 </span>   <span class="Constant"> .          .</span>
+<span id="L1517" class="LineNr">1517 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1518" class="LineNr">1518 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L1519" class="LineNr">1519 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1520" class="LineNr">1520 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1521" class="LineNr">1521 </span>  ]
 <span id="L1522" class="LineNr">1522 </span>  <span class="Comment"># cursor moves</span>
 <span id="L1523" class="LineNr">1523 </span>  memory-should-contain [
-<span id="L1524" class="LineNr">1524 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1525" class="LineNr">1525 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1524" class="LineNr">1524 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1525" class="LineNr">1525 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L1526" class="LineNr">1526 </span>  ]
 <span id="L1527" class="LineNr">1527 </span>  <span class="Comment"># redo again</span>
 <span id="L1528" class="LineNr">1528 </span>  assume-console [
-<span id="L1529" class="LineNr">1529 </span>    press ctrl-y
+<span id="L1529" class="LineNr">1529 </span>  <span class="Conceal">¦</span> press ctrl-y
 <span id="L1530" class="LineNr">1530 </span>  ]
 <span id="L1531" class="LineNr">1531 </span>  run [
-<span id="L1532" class="LineNr">1532 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
-<span id="L1533" class="LineNr">1533 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
-<span id="L1534" class="LineNr">1534 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
+<span id="L1532" class="LineNr">1532 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1533" class="LineNr">1533 </span>  <span class="Conceal">¦</span> 3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
+<span id="L1534" class="LineNr">1534 </span>  <span class="Conceal">¦</span> 4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1535" class="LineNr">1535 </span>  ]
 <span id="L1536" class="LineNr">1536 </span>  <span class="Comment"># second insert</span>
 <span id="L1537" class="LineNr">1537 </span>  screen-should-contain [
-<span id="L1538" class="LineNr">1538 </span>   <span class="Constant"> .          .</span>
-<span id="L1539" class="LineNr">1539 </span>   <span class="Constant"> .adbc      .</span>
-<span id="L1540" class="LineNr">1540 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1541" class="LineNr">1541 </span>   <span class="Constant"> .          .</span>
+<span id="L1538" class="LineNr">1538 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1539" class="LineNr">1539 </span>  <span class="Conceal">¦</span><span class="Constant"> .adbc      .</span>
+<span id="L1540" class="LineNr">1540 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1541" class="LineNr">1541 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1542" class="LineNr">1542 </span>  ]
 <span id="L1543" class="LineNr">1543 </span>  memory-should-contain [
-<span id="L1544" class="LineNr">1544 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1545" class="LineNr">1545 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L1544" class="LineNr">1544 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1545" class="LineNr">1545 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
 <span id="L1546" class="LineNr">1546 </span>  ]
 <span id="L1547" class="LineNr">1547 </span>]
 <span id="L1548" class="LineNr">1548 </span>
@@ -1617,60 +1618,60 @@ if ('onhashchange' in window) {
 <span id="L1556" class="LineNr">1556 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L1557" class="LineNr">1557 </span>  <span class="Comment"># insert some text and hit backspace</span>
 <span id="L1558" class="LineNr">1558 </span>  assume-console [
-<span id="L1559" class="LineNr">1559 </span>    type <span class="Constant">[abc]</span>
-<span id="L1560" class="LineNr">1560 </span>    press backspace
-<span id="L1561" class="LineNr">1561 </span>    press backspace
+<span id="L1559" class="LineNr">1559 </span>  <span class="Conceal">¦</span> type <span class="Constant">[abc]</span>
+<span id="L1560" class="LineNr">1560 </span>  <span class="Conceal">¦</span> press backspace
+<span id="L1561" class="LineNr">1561 </span>  <span class="Conceal">¦</span> press backspace
 <span id="L1562" class="LineNr">1562 </span>  ]
 <span id="L1563" class="LineNr">1563 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1564" class="LineNr">1564 </span>  screen-should-contain [
-<span id="L1565" class="LineNr">1565 </span>   <span class="Constant"> .          .</span>
-<span id="L1566" class="LineNr">1566 </span>   <span class="Constant"> .a         .</span>
-<span id="L1567" class="LineNr">1567 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1568" class="LineNr">1568 </span>   <span class="Constant"> .          .</span>
+<span id="L1565" class="LineNr">1565 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1566" class="LineNr">1566 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L1567" class="LineNr">1567 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1568" class="LineNr">1568 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1569" class="LineNr">1569 </span>  ]
 <span id="L1570" class="LineNr">1570 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L1571" class="LineNr">1571 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1572" class="LineNr">1572 </span>  memory-should-contain [
-<span id="L1573" class="LineNr">1573 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1574" class="LineNr">1574 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1573" class="LineNr">1573 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1574" class="LineNr">1574 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L1575" class="LineNr">1575 </span>  ]
 <span id="L1576" class="LineNr">1576 </span>  <span class="Comment"># undo</span>
 <span id="L1577" class="LineNr">1577 </span>  assume-console [
-<span id="L1578" class="LineNr">1578 </span>    press ctrl-z
+<span id="L1578" class="LineNr">1578 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L1579" class="LineNr">1579 </span>  ]
 <span id="L1580" class="LineNr">1580 </span>  run [
-<span id="L1581" class="LineNr">1581 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1581" class="LineNr">1581 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1582" class="LineNr">1582 </span>  ]
 <span id="L1583" class="LineNr">1583 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L1584" class="LineNr">1584 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1585" class="LineNr">1585 </span>  memory-should-contain [
-<span id="L1586" class="LineNr">1586 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1587" class="LineNr">1587 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L1586" class="LineNr">1586 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1587" class="LineNr">1587 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
 <span id="L1588" class="LineNr">1588 </span>  ]
 <span id="L1589" class="LineNr">1589 </span>  screen-should-contain [
-<span id="L1590" class="LineNr">1590 </span>   <span class="Constant"> .          .</span>
-<span id="L1591" class="LineNr">1591 </span>   <span class="Constant"> .abc       .</span>
-<span id="L1592" class="LineNr">1592 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1593" class="LineNr">1593 </span>   <span class="Constant"> .          .</span>
+<span id="L1590" class="LineNr">1590 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1591" class="LineNr">1591 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L1592" class="LineNr">1592 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1593" class="LineNr">1593 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1594" class="LineNr">1594 </span>  ]
 <span id="L1595" class="LineNr">1595 </span>  <span class="Comment"># redo</span>
 <span id="L1596" class="LineNr">1596 </span>  assume-console [
-<span id="L1597" class="LineNr">1597 </span>    press ctrl-y
+<span id="L1597" class="LineNr">1597 </span>  <span class="Conceal">¦</span> press ctrl-y
 <span id="L1598" class="LineNr">1598 </span>  ]
 <span id="L1599" class="LineNr">1599 </span>  run [
-<span id="L1600" class="LineNr">1600 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1600" class="LineNr">1600 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1601" class="LineNr">1601 </span>  ]
 <span id="L1602" class="LineNr">1602 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L1603" class="LineNr">1603 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1604" class="LineNr">1604 </span>  memory-should-contain [
-<span id="L1605" class="LineNr">1605 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1606" class="LineNr">1606 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1605" class="LineNr">1605 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1606" class="LineNr">1606 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L1607" class="LineNr">1607 </span>  ]
 <span id="L1608" class="LineNr">1608 </span>  screen-should-contain [
-<span id="L1609" class="LineNr">1609 </span>   <span class="Constant"> .          .</span>
-<span id="L1610" class="LineNr">1610 </span>   <span class="Constant"> .a         .</span>
-<span id="L1611" class="LineNr">1611 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1612" class="LineNr">1612 </span>   <span class="Constant"> .          .</span>
+<span id="L1609" class="LineNr">1609 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1610" class="LineNr">1610 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L1611" class="LineNr">1611 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1612" class="LineNr">1612 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1613" class="LineNr">1613 </span>  ]
 <span id="L1614" class="LineNr">1614 </span>]
 <span id="L1615" class="LineNr">1615 </span>
@@ -1680,75 +1681,75 @@ if ('onhashchange' in window) {
 <span id="L1619" class="LineNr">1619 </span>]
 <span id="L1620" class="LineNr">1620 </span><span class="muRecipe">before</span> <span class="Constant"><a href='003-shortcuts.mu.html#L75'>&lt;backspace-character-end&gt;</a></span> [
 <span id="L1621" class="LineNr">1621 </span>  <span class="Delimiter">{</span>
-<span id="L1622" class="LineNr">1622 </span>    <span class="muControl">break-unless</span> backspaced-cell  <span class="Comment"># backspace failed; don't add an undo operation</span>
-<span id="L1623" class="LineNr">1623 </span>    top-after:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
-<span id="L1624" class="LineNr">1624 </span>    cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
-<span id="L1625" class="LineNr">1625 </span>    cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
-<span id="L1626" class="LineNr">1626 </span>    before-cursor:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
-<span id="L1627" class="LineNr">1627 </span>    undo:&amp;:list:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">undo:offset</span>
-<span id="L1628" class="LineNr">1628 </span>    <span class="Delimiter">{</span>
-<span id="L1629" class="LineNr">1629 </span>      <span class="Comment"># if previous operation was an insert, coalesce this operation with it</span>
-<span id="L1630" class="LineNr">1630 </span>      <span class="muControl">break-unless</span> undo
-<span id="L1631" class="LineNr">1631 </span>      op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> first undo
-<span id="L1632" class="LineNr">1632 </span>      deletion:<a href='012-editor-undo.mu.html#L41'>delete-operation</a>, is-delete?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">delete:variant</span>
-<span id="L1633" class="LineNr">1633 </span>      <span class="muControl">break-unless</span> is-delete?
-<span id="L1634" class="LineNr">1634 </span>      previous-coalesce-tag:num <span class="Special">&lt;-</span> get deletion, <span class="Constant">tag:offset</span>
-<span id="L1635" class="LineNr">1635 </span>      coalesce?:bool <span class="Special">&lt;-</span> equal previous-coalesce-tag, <span class="Constant">1/coalesce-backspace</span>
-<span id="L1636" class="LineNr">1636 </span>      <span class="muControl">break-unless</span> coalesce?
-<span id="L1637" class="LineNr">1637 </span>      deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">delete-from:offset</span>, before-cursor
-<span id="L1638" class="LineNr">1638 </span>      backspaced-so-far:&amp;:duplex-list:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">deleted-text:offset</span>
-<span id="L1639" class="LineNr">1639 </span>      <a href='../065duplex_list.mu.html#L485'>insert-range</a> backspaced-cell, backspaced-so-far
-<span id="L1640" class="LineNr">1640 </span>      deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">deleted-text:offset</span>, backspaced-cell
-<span id="L1641" class="LineNr">1641 </span>      deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">after-row:offset</span>, cursor-row
-<span id="L1642" class="LineNr">1642 </span>      deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">after-column:offset</span>, cursor-column
-<span id="L1643" class="LineNr">1643 </span>      deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">after-top-of-screen:offset</span>, top-after
-<span id="L1644" class="LineNr">1644 </span>      *op <span class="Special">&lt;-</span> merge <span class="Constant">2/delete-operation</span>, deletion
-<span id="L1645" class="LineNr">1645 </span>      <span class="muControl">break</span> <span class="Constant">+done-adding-backspace-operation</span>
-<span id="L1646" class="LineNr">1646 </span>    <span class="Delimiter">}</span>
-<span id="L1647" class="LineNr">1647 </span>    <span class="Comment"># if not, create a new operation</span>
-<span id="L1648" class="LineNr">1648 </span>    op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> new <span class="Constant"><a href='012-editor-undo.mu.html#L5'>operation</a>:type</span>
-<span id="L1649" class="LineNr">1649 </span>    deleted-until:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
-<span id="L1650" class="LineNr">1650 </span>    *op <span class="Special">&lt;-</span> merge <span class="Constant">2/delete-operation</span>, save-row/before, save-column/before, top-before, cursor-row/after, cursor-column/after, top-after, backspaced-cell/deleted, before-cursor/delete-from, deleted-until, <span class="Constant">1/coalesce-backspace</span>
-<span id="L1651" class="LineNr">1651 </span>    editor <span class="Special">&lt;-</span> <a href='012-editor-undo.mu.html#L200'>add-operation</a> editor, op
-<span id="L1652" class="LineNr">1652 </span><span class="Constant">    +done-adding-backspace-operation</span>
+<span id="L1622" class="LineNr">1622 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> backspaced-cell  <span class="Comment"># backspace failed; don't add an undo operation</span>
+<span id="L1623" class="LineNr">1623 </span>  <span class="Conceal">¦</span> top-after:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
+<span id="L1624" class="LineNr">1624 </span>  <span class="Conceal">¦</span> cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
+<span id="L1625" class="LineNr">1625 </span>  <span class="Conceal">¦</span> cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
+<span id="L1626" class="LineNr">1626 </span>  <span class="Conceal">¦</span> before-cursor:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
+<span id="L1627" class="LineNr">1627 </span>  <span class="Conceal">¦</span> undo:&amp;:list:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">undo:offset</span>
+<span id="L1628" class="LineNr">1628 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L1629" class="LineNr">1629 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># if previous operation was an insert, coalesce this operation with it</span>
+<span id="L1630" class="LineNr">1630 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> undo
+<span id="L1631" class="LineNr">1631 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> first undo
+<span id="L1632" class="LineNr">1632 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion:<a href='012-editor-undo.mu.html#L41'>delete-operation</a>, is-delete?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">delete:variant</span>
+<span id="L1633" class="LineNr">1633 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-delete?
+<span id="L1634" class="LineNr">1634 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> previous-coalesce-tag:num <span class="Special">&lt;-</span> get deletion, <span class="Constant">tag:offset</span>
+<span id="L1635" class="LineNr">1635 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> coalesce?:bool <span class="Special">&lt;-</span> equal previous-coalesce-tag, <span class="Constant">1/coalesce-backspace</span>
+<span id="L1636" class="LineNr">1636 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> coalesce?
+<span id="L1637" class="LineNr">1637 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">delete-from:offset</span>, before-cursor
+<span id="L1638" class="LineNr">1638 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> backspaced-so-far:&amp;:duplex-list:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">deleted-text:offset</span>
+<span id="L1639" class="LineNr">1639 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L485'>insert-range</a> backspaced-cell, backspaced-so-far
+<span id="L1640" class="LineNr">1640 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">deleted-text:offset</span>, backspaced-cell
+<span id="L1641" class="LineNr">1641 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">after-row:offset</span>, cursor-row
+<span id="L1642" class="LineNr">1642 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">after-column:offset</span>, cursor-column
+<span id="L1643" class="LineNr">1643 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">after-top-of-screen:offset</span>, top-after
+<span id="L1644" class="LineNr">1644 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> *op <span class="Special">&lt;-</span> merge <span class="Constant">2/delete-operation</span>, deletion
+<span id="L1645" class="LineNr">1645 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break</span> <span class="Constant">+done-adding-backspace-operation</span>
+<span id="L1646" class="LineNr">1646 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L1647" class="LineNr">1647 </span>  <span class="Conceal">¦</span> <span class="Comment"># if not, create a new operation</span>
+<span id="L1648" class="LineNr">1648 </span>  <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> new <span class="Constant"><a href='012-editor-undo.mu.html#L5'>operation</a>:type</span>
+<span id="L1649" class="LineNr">1649 </span>  <span class="Conceal">¦</span> deleted-until:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L1650" class="LineNr">1650 </span>  <span class="Conceal">¦</span> *op <span class="Special">&lt;-</span> merge <span class="Constant">2/delete-operation</span>, save-row/before, save-column/before, top-before, cursor-row/after, cursor-column/after, top-after, backspaced-cell/deleted, before-cursor/delete-from, deleted-until, <span class="Constant">1/coalesce-backspace</span>
+<span id="L1651" class="LineNr">1651 </span>  <span class="Conceal">¦</span> editor <span class="Special">&lt;-</span> <a href='012-editor-undo.mu.html#L200'>add-operation</a> editor, op
+<span id="L1652" class="LineNr">1652 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> +done-adding-backspace-operation</span>
 <span id="L1653" class="LineNr">1653 </span>  <span class="Delimiter">}</span>
 <span id="L1654" class="LineNr">1654 </span>]
 <span id="L1655" class="LineNr">1655 </span>
 <span id="L1656" class="LineNr">1656 </span><span class="muRecipe">after</span> <span class="Constant"><a href='012-editor-undo.mu.html#L76'>&lt;handle-undo&gt;</a></span> [
 <span id="L1657" class="LineNr">1657 </span>  <span class="Delimiter">{</span>
-<span id="L1658" class="LineNr">1658 </span>    deletion:<a href='012-editor-undo.mu.html#L41'>delete-operation</a>, is-delete?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">delete:variant</span>
-<span id="L1659" class="LineNr">1659 </span>    <span class="muControl">break-unless</span> is-delete?
-<span id="L1660" class="LineNr">1660 </span>    anchor:&amp;:duplex-list:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">delete-from:offset</span>
-<span id="L1661" class="LineNr">1661 </span>    <span class="muControl">break-unless</span> anchor
-<span id="L1662" class="LineNr">1662 </span>    deleted:&amp;:duplex-list:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">deleted-text:offset</span>
-<span id="L1663" class="LineNr">1663 </span>    old-cursor:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L516'>last</a> deleted
-<span id="L1664" class="LineNr">1664 </span>    <a href='../065duplex_list.mu.html#L485'>insert-range</a> anchor, deleted
-<span id="L1665" class="LineNr">1665 </span>    <span class="Comment"># assert cursor-row/cursor-column/top-of-screen match after-row/after-column/after-top-of-screen</span>
-<span id="L1666" class="LineNr">1666 </span>    before-cursor <span class="Special">&lt;-</span> copy old-cursor
-<span id="L1667" class="LineNr">1667 </span>    cursor-row <span class="Special">&lt;-</span> get deletion, <span class="Constant">before-row:offset</span>
-<span id="L1668" class="LineNr">1668 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
-<span id="L1669" class="LineNr">1669 </span>    cursor-column <span class="Special">&lt;-</span> get deletion, <span class="Constant">before-column:offset</span>
-<span id="L1670" class="LineNr">1670 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
-<span id="L1671" class="LineNr">1671 </span>    top:&amp;:duplex-list:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">before-top-of-screen:offset</span>
-<span id="L1672" class="LineNr">1672 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top
+<span id="L1658" class="LineNr">1658 </span>  <span class="Conceal">¦</span> deletion:<a href='012-editor-undo.mu.html#L41'>delete-operation</a>, is-delete?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">delete:variant</span>
+<span id="L1659" class="LineNr">1659 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-delete?
+<span id="L1660" class="LineNr">1660 </span>  <span class="Conceal">¦</span> anchor:&amp;:duplex-list:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">delete-from:offset</span>
+<span id="L1661" class="LineNr">1661 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> anchor
+<span id="L1662" class="LineNr">1662 </span>  <span class="Conceal">¦</span> deleted:&amp;:duplex-list:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">deleted-text:offset</span>
+<span id="L1663" class="LineNr">1663 </span>  <span class="Conceal">¦</span> old-cursor:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L516'>last</a> deleted
+<span id="L1664" class="LineNr">1664 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L485'>insert-range</a> anchor, deleted
+<span id="L1665" class="LineNr">1665 </span>  <span class="Conceal">¦</span> <span class="Comment"># assert cursor-row/cursor-column/top-of-screen match after-row/after-column/after-top-of-screen</span>
+<span id="L1666" class="LineNr">1666 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy old-cursor
+<span id="L1667" class="LineNr">1667 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> get deletion, <span class="Constant">before-row:offset</span>
+<span id="L1668" class="LineNr">1668 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
+<span id="L1669" class="LineNr">1669 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> get deletion, <span class="Constant">before-column:offset</span>
+<span id="L1670" class="LineNr">1670 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
+<span id="L1671" class="LineNr">1671 </span>  <span class="Conceal">¦</span> top:&amp;:duplex-list:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">before-top-of-screen:offset</span>
+<span id="L1672" class="LineNr">1672 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top
 <span id="L1673" class="LineNr">1673 </span>  <span class="Delimiter">}</span>
 <span id="L1674" class="LineNr">1674 </span>]
 <span id="L1675" class="LineNr">1675 </span>
 <span id="L1676" class="LineNr">1676 </span><span class="muRecipe">after</span> <span class="Constant"><a href='012-editor-undo.mu.html#L94'>&lt;handle-redo&gt;</a></span> [
 <span id="L1677" class="LineNr">1677 </span>  <span class="Delimiter">{</span>
-<span id="L1678" class="LineNr">1678 </span>    deletion:<a href='012-editor-undo.mu.html#L41'>delete-operation</a>, is-delete?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">delete:variant</span>
-<span id="L1679" class="LineNr">1679 </span>    <span class="muControl">break-unless</span> is-delete?
-<span id="L1680" class="LineNr">1680 </span>    start:&amp;:duplex-list:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">delete-from:offset</span>
-<span id="L1681" class="LineNr">1681 </span>    end:&amp;:duplex-list:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">delete-until:offset</span>
-<span id="L1682" class="LineNr">1682 </span>    data:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
-<span id="L1683" class="LineNr">1683 </span>    <a href='../065duplex_list.mu.html#L345'>remove-between</a> start, end
-<span id="L1684" class="LineNr">1684 </span>    <span class="Comment"># assert cursor-row/cursor-column/top-of-screen match after-row/after-column/after-top-of-screen</span>
-<span id="L1685" class="LineNr">1685 </span>    cursor-row <span class="Special">&lt;-</span> get deletion, <span class="Constant">after-row:offset</span>
-<span id="L1686" class="LineNr">1686 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
-<span id="L1687" class="LineNr">1687 </span>    cursor-column <span class="Special">&lt;-</span> get deletion, <span class="Constant">after-column:offset</span>
-<span id="L1688" class="LineNr">1688 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
-<span id="L1689" class="LineNr">1689 </span>    top:&amp;:duplex-list:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">before-top-of-screen:offset</span>
-<span id="L1690" class="LineNr">1690 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top
+<span id="L1678" class="LineNr">1678 </span>  <span class="Conceal">¦</span> deletion:<a href='012-editor-undo.mu.html#L41'>delete-operation</a>, is-delete?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">delete:variant</span>
+<span id="L1679" class="LineNr">1679 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-delete?
+<span id="L1680" class="LineNr">1680 </span>  <span class="Conceal">¦</span> start:&amp;:duplex-list:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">delete-from:offset</span>
+<span id="L1681" class="LineNr">1681 </span>  <span class="Conceal">¦</span> end:&amp;:duplex-list:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">delete-until:offset</span>
+<span id="L1682" class="LineNr">1682 </span>  <span class="Conceal">¦</span> data:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
+<span id="L1683" class="LineNr">1683 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L345'>remove-between</a> start, end
+<span id="L1684" class="LineNr">1684 </span>  <span class="Conceal">¦</span> <span class="Comment"># assert cursor-row/cursor-column/top-of-screen match after-row/after-column/after-top-of-screen</span>
+<span id="L1685" class="LineNr">1685 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> get deletion, <span class="Constant">after-row:offset</span>
+<span id="L1686" class="LineNr">1686 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
+<span id="L1687" class="LineNr">1687 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> get deletion, <span class="Constant">after-column:offset</span>
+<span id="L1688" class="LineNr">1688 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
+<span id="L1689" class="LineNr">1689 </span>  <span class="Conceal">¦</span> top:&amp;:duplex-list:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">before-top-of-screen:offset</span>
+<span id="L1690" class="LineNr">1690 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top
 <span id="L1691" class="LineNr">1691 </span>  <span class="Delimiter">}</span>
 <span id="L1692" class="LineNr">1692 </span>]
 <span id="L1693" class="LineNr">1693 </span>
@@ -1762,142 +1763,142 @@ if ('onhashchange' in window) {
 <span id="L1701" class="LineNr">1701 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L1702" class="LineNr">1702 </span>  <span class="Comment"># insert some text and hit delete and backspace a few times</span>
 <span id="L1703" class="LineNr">1703 </span>  assume-console [
-<span id="L1704" class="LineNr">1704 </span>    type <span class="Constant">[abcdef]</span>
-<span id="L1705" class="LineNr">1705 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 2</span>
-<span id="L1706" class="LineNr">1706 </span>    press delete
-<span id="L1707" class="LineNr">1707 </span>    press backspace
-<span id="L1708" class="LineNr">1708 </span>    press delete
-<span id="L1709" class="LineNr">1709 </span>    press delete
+<span id="L1704" class="LineNr">1704 </span>  <span class="Conceal">¦</span> type <span class="Constant">[abcdef]</span>
+<span id="L1705" class="LineNr">1705 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 2</span>
+<span id="L1706" class="LineNr">1706 </span>  <span class="Conceal">¦</span> press delete
+<span id="L1707" class="LineNr">1707 </span>  <span class="Conceal">¦</span> press backspace
+<span id="L1708" class="LineNr">1708 </span>  <span class="Conceal">¦</span> press delete
+<span id="L1709" class="LineNr">1709 </span>  <span class="Conceal">¦</span> press delete
 <span id="L1710" class="LineNr">1710 </span>  ]
 <span id="L1711" class="LineNr">1711 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1712" class="LineNr">1712 </span>  screen-should-contain [
-<span id="L1713" class="LineNr">1713 </span>   <span class="Constant"> .          .</span>
-<span id="L1714" class="LineNr">1714 </span>   <span class="Constant"> .af        .</span>
-<span id="L1715" class="LineNr">1715 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1716" class="LineNr">1716 </span>   <span class="Constant"> .          .</span>
+<span id="L1713" class="LineNr">1713 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1714" class="LineNr">1714 </span>  <span class="Conceal">¦</span><span class="Constant"> .af        .</span>
+<span id="L1715" class="LineNr">1715 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1716" class="LineNr">1716 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1717" class="LineNr">1717 </span>  ]
 <span id="L1718" class="LineNr">1718 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L1719" class="LineNr">1719 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1720" class="LineNr">1720 </span>  memory-should-contain [
-<span id="L1721" class="LineNr">1721 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1722" class="LineNr">1722 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1721" class="LineNr">1721 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1722" class="LineNr">1722 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L1723" class="LineNr">1723 </span>  ]
 <span id="L1724" class="LineNr">1724 </span>  <span class="Comment"># undo deletes</span>
 <span id="L1725" class="LineNr">1725 </span>  assume-console [
-<span id="L1726" class="LineNr">1726 </span>    press ctrl-z
+<span id="L1726" class="LineNr">1726 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L1727" class="LineNr">1727 </span>  ]
 <span id="L1728" class="LineNr">1728 </span>  run [
-<span id="L1729" class="LineNr">1729 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1729" class="LineNr">1729 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1730" class="LineNr">1730 </span>  ]
 <span id="L1731" class="LineNr">1731 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L1732" class="LineNr">1732 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1733" class="LineNr">1733 </span>  memory-should-contain [
-<span id="L1734" class="LineNr">1734 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1735" class="LineNr">1735 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1734" class="LineNr">1734 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1735" class="LineNr">1735 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L1736" class="LineNr">1736 </span>  ]
 <span id="L1737" class="LineNr">1737 </span>  screen-should-contain [
-<span id="L1738" class="LineNr">1738 </span>   <span class="Constant"> .          .</span>
-<span id="L1739" class="LineNr">1739 </span>   <span class="Constant"> .adef      .</span>
-<span id="L1740" class="LineNr">1740 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1741" class="LineNr">1741 </span>   <span class="Constant"> .          .</span>
+<span id="L1738" class="LineNr">1738 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1739" class="LineNr">1739 </span>  <span class="Conceal">¦</span><span class="Constant"> .adef      .</span>
+<span id="L1740" class="LineNr">1740 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1741" class="LineNr">1741 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1742" class="LineNr">1742 </span>  ]
 <span id="L1743" class="LineNr">1743 </span>  <span class="Comment"># undo backspace</span>
 <span id="L1744" class="LineNr">1744 </span>  assume-console [
-<span id="L1745" class="LineNr">1745 </span>    press ctrl-z
+<span id="L1745" class="LineNr">1745 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L1746" class="LineNr">1746 </span>  ]
 <span id="L1747" class="LineNr">1747 </span>  run [
-<span id="L1748" class="LineNr">1748 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1748" class="LineNr">1748 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1749" class="LineNr">1749 </span>  ]
 <span id="L1750" class="LineNr">1750 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L1751" class="LineNr">1751 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1752" class="LineNr">1752 </span>  memory-should-contain [
-<span id="L1753" class="LineNr">1753 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1754" class="LineNr">1754 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L1753" class="LineNr">1753 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1754" class="LineNr">1754 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
 <span id="L1755" class="LineNr">1755 </span>  ]
 <span id="L1756" class="LineNr">1756 </span>  screen-should-contain [
-<span id="L1757" class="LineNr">1757 </span>   <span class="Constant"> .          .</span>
-<span id="L1758" class="LineNr">1758 </span>   <span class="Constant"> .abdef     .</span>
-<span id="L1759" class="LineNr">1759 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1760" class="LineNr">1760 </span>   <span class="Constant"> .          .</span>
+<span id="L1757" class="LineNr">1757 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1758" class="LineNr">1758 </span>  <span class="Conceal">¦</span><span class="Constant"> .abdef     .</span>
+<span id="L1759" class="LineNr">1759 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1760" class="LineNr">1760 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1761" class="LineNr">1761 </span>  ]
 <span id="L1762" class="LineNr">1762 </span>  <span class="Comment"># undo first delete</span>
 <span id="L1763" class="LineNr">1763 </span>  assume-console [
-<span id="L1764" class="LineNr">1764 </span>    press ctrl-z
+<span id="L1764" class="LineNr">1764 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L1765" class="LineNr">1765 </span>  ]
 <span id="L1766" class="LineNr">1766 </span>  run [
-<span id="L1767" class="LineNr">1767 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1767" class="LineNr">1767 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1768" class="LineNr">1768 </span>  ]
 <span id="L1769" class="LineNr">1769 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L1770" class="LineNr">1770 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1771" class="LineNr">1771 </span>  memory-should-contain [
-<span id="L1772" class="LineNr">1772 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1773" class="LineNr">1773 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L1772" class="LineNr">1772 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1773" class="LineNr">1773 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
 <span id="L1774" class="LineNr">1774 </span>  ]
 <span id="L1775" class="LineNr">1775 </span>  screen-should-contain [
-<span id="L1776" class="LineNr">1776 </span>   <span class="Constant"> .          .</span>
-<span id="L1777" class="LineNr">1777 </span>   <span class="Constant"> .abcdef    .</span>
-<span id="L1778" class="LineNr">1778 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1779" class="LineNr">1779 </span>   <span class="Constant"> .          .</span>
+<span id="L1776" class="LineNr">1776 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1777" class="LineNr">1777 </span>  <span class="Conceal">¦</span><span class="Constant"> .abcdef    .</span>
+<span id="L1778" class="LineNr">1778 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1779" class="LineNr">1779 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1780" class="LineNr">1780 </span>  ]
 <span id="L1781" class="LineNr">1781 </span>  <span class="Comment"># redo first delete</span>
 <span id="L1782" class="LineNr">1782 </span>  assume-console [
-<span id="L1783" class="LineNr">1783 </span>    press ctrl-y
+<span id="L1783" class="LineNr">1783 </span>  <span class="Conceal">¦</span> press ctrl-y
 <span id="L1784" class="LineNr">1784 </span>  ]
 <span id="L1785" class="LineNr">1785 </span>  run [
-<span id="L1786" class="LineNr">1786 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1786" class="LineNr">1786 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1787" class="LineNr">1787 </span>  ]
 <span id="L1788" class="LineNr">1788 </span>  <span class="Comment"># first line inserted</span>
 <span id="L1789" class="LineNr">1789 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L1790" class="LineNr">1790 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1791" class="LineNr">1791 </span>  memory-should-contain [
-<span id="L1792" class="LineNr">1792 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1793" class="LineNr">1793 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L1792" class="LineNr">1792 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1793" class="LineNr">1793 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
 <span id="L1794" class="LineNr">1794 </span>  ]
 <span id="L1795" class="LineNr">1795 </span>  screen-should-contain [
-<span id="L1796" class="LineNr">1796 </span>   <span class="Constant"> .          .</span>
-<span id="L1797" class="LineNr">1797 </span>   <span class="Constant"> .abdef     .</span>
-<span id="L1798" class="LineNr">1798 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1799" class="LineNr">1799 </span>   <span class="Constant"> .          .</span>
+<span id="L1796" class="LineNr">1796 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1797" class="LineNr">1797 </span>  <span class="Conceal">¦</span><span class="Constant"> .abdef     .</span>
+<span id="L1798" class="LineNr">1798 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1799" class="LineNr">1799 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1800" class="LineNr">1800 </span>  ]
 <span id="L1801" class="LineNr">1801 </span>  <span class="Comment"># redo backspace</span>
 <span id="L1802" class="LineNr">1802 </span>  assume-console [
-<span id="L1803" class="LineNr">1803 </span>    press ctrl-y
+<span id="L1803" class="LineNr">1803 </span>  <span class="Conceal">¦</span> press ctrl-y
 <span id="L1804" class="LineNr">1804 </span>  ]
 <span id="L1805" class="LineNr">1805 </span>  run [
-<span id="L1806" class="LineNr">1806 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1806" class="LineNr">1806 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1807" class="LineNr">1807 </span>  ]
 <span id="L1808" class="LineNr">1808 </span>  <span class="Comment"># first line inserted</span>
 <span id="L1809" class="LineNr">1809 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L1810" class="LineNr">1810 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1811" class="LineNr">1811 </span>  memory-should-contain [
-<span id="L1812" class="LineNr">1812 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1813" class="LineNr">1813 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1812" class="LineNr">1812 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1813" class="LineNr">1813 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L1814" class="LineNr">1814 </span>  ]
 <span id="L1815" class="LineNr">1815 </span>  screen-should-contain [
-<span id="L1816" class="LineNr">1816 </span>   <span class="Constant"> .          .</span>
-<span id="L1817" class="LineNr">1817 </span>   <span class="Constant"> .adef      .</span>
-<span id="L1818" class="LineNr">1818 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1819" class="LineNr">1819 </span>   <span class="Constant"> .          .</span>
+<span id="L1816" class="LineNr">1816 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1817" class="LineNr">1817 </span>  <span class="Conceal">¦</span><span class="Constant"> .adef      .</span>
+<span id="L1818" class="LineNr">1818 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1819" class="LineNr">1819 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1820" class="LineNr">1820 </span>  ]
 <span id="L1821" class="LineNr">1821 </span>  <span class="Comment"># redo deletes</span>
 <span id="L1822" class="LineNr">1822 </span>  assume-console [
-<span id="L1823" class="LineNr">1823 </span>    press ctrl-y
+<span id="L1823" class="LineNr">1823 </span>  <span class="Conceal">¦</span> press ctrl-y
 <span id="L1824" class="LineNr">1824 </span>  ]
 <span id="L1825" class="LineNr">1825 </span>  run [
-<span id="L1826" class="LineNr">1826 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1826" class="LineNr">1826 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1827" class="LineNr">1827 </span>  ]
 <span id="L1828" class="LineNr">1828 </span>  <span class="Comment"># first line inserted</span>
 <span id="L1829" class="LineNr">1829 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L1830" class="LineNr">1830 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1831" class="LineNr">1831 </span>  memory-should-contain [
-<span id="L1832" class="LineNr">1832 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1833" class="LineNr">1833 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1832" class="LineNr">1832 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1833" class="LineNr">1833 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L1834" class="LineNr">1834 </span>  ]
 <span id="L1835" class="LineNr">1835 </span>  screen-should-contain [
-<span id="L1836" class="LineNr">1836 </span>   <span class="Constant"> .          .</span>
-<span id="L1837" class="LineNr">1837 </span>   <span class="Constant"> .af        .</span>
-<span id="L1838" class="LineNr">1838 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1839" class="LineNr">1839 </span>   <span class="Constant"> .          .</span>
+<span id="L1836" class="LineNr">1836 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1837" class="LineNr">1837 </span>  <span class="Conceal">¦</span><span class="Constant"> .af        .</span>
+<span id="L1838" class="LineNr">1838 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1839" class="LineNr">1839 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1840" class="LineNr">1840 </span>  ]
 <span id="L1841" class="LineNr">1841 </span>]
 <span id="L1842" class="LineNr">1842 </span>
@@ -1906,38 +1907,38 @@ if ('onhashchange' in window) {
 <span id="L1845" class="LineNr">1845 </span>]
 <span id="L1846" class="LineNr">1846 </span><span class="muRecipe">before</span> <span class="Constant"><a href='003-shortcuts.mu.html#L343'>&lt;delete-character-end&gt;</a></span> [
 <span id="L1847" class="LineNr">1847 </span>  <span class="Delimiter">{</span>
-<span id="L1848" class="LineNr">1848 </span>    <span class="muControl">break-unless</span> deleted-cell  <span class="Comment"># delete failed; don't add an undo operation</span>
-<span id="L1849" class="LineNr">1849 </span>    top-after:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
-<span id="L1850" class="LineNr">1850 </span>    cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
-<span id="L1851" class="LineNr">1851 </span>    cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
-<span id="L1852" class="LineNr">1852 </span>    before-cursor:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
-<span id="L1853" class="LineNr">1853 </span>    undo:&amp;:list:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">undo:offset</span>
-<span id="L1854" class="LineNr">1854 </span>    <span class="Delimiter">{</span>
-<span id="L1855" class="LineNr">1855 </span>      <span class="Comment"># if previous operation was an insert, coalesce this operation with it</span>
-<span id="L1856" class="LineNr">1856 </span>      <span class="muControl">break-unless</span> undo
-<span id="L1857" class="LineNr">1857 </span>      op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> first undo
-<span id="L1858" class="LineNr">1858 </span>      deletion:<a href='012-editor-undo.mu.html#L41'>delete-operation</a>, is-delete?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">delete:variant</span>
-<span id="L1859" class="LineNr">1859 </span>      <span class="muControl">break-unless</span> is-delete?
-<span id="L1860" class="LineNr">1860 </span>      previous-coalesce-tag:num <span class="Special">&lt;-</span> get deletion, <span class="Constant">tag:offset</span>
-<span id="L1861" class="LineNr">1861 </span>      coalesce?:bool <span class="Special">&lt;-</span> equal previous-coalesce-tag, <span class="Constant">2/coalesce-delete</span>
-<span id="L1862" class="LineNr">1862 </span>      <span class="muControl">break-unless</span> coalesce?
-<span id="L1863" class="LineNr">1863 </span>      delete-until:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
-<span id="L1864" class="LineNr">1864 </span>      deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">delete-until:offset</span>, delete-until
-<span id="L1865" class="LineNr">1865 </span>      deleted-so-far:&amp;:duplex-list:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">deleted-text:offset</span>
-<span id="L1866" class="LineNr">1866 </span>      deleted-so-far <span class="Special">&lt;-</span> append deleted-so-far, deleted-cell
-<span id="L1867" class="LineNr">1867 </span>      deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">deleted-text:offset</span>, deleted-so-far
-<span id="L1868" class="LineNr">1868 </span>      deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">after-row:offset</span>, cursor-row
-<span id="L1869" class="LineNr">1869 </span>      deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">after-column:offset</span>, cursor-column
-<span id="L1870" class="LineNr">1870 </span>      deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">after-top-of-screen:offset</span>, top-after
-<span id="L1871" class="LineNr">1871 </span>      *op <span class="Special">&lt;-</span> merge <span class="Constant">2/delete-operation</span>, deletion
-<span id="L1872" class="LineNr">1872 </span>      <span class="muControl">break</span> <span class="Constant">+done-adding-delete-operation</span>
-<span id="L1873" class="LineNr">1873 </span>    <span class="Delimiter">}</span>
-<span id="L1874" class="LineNr">1874 </span>    <span class="Comment"># if not, create a new operation</span>
-<span id="L1875" class="LineNr">1875 </span>    op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> new <span class="Constant"><a href='012-editor-undo.mu.html#L5'>operation</a>:type</span>
-<span id="L1876" class="LineNr">1876 </span>    deleted-until:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
-<span id="L1877" class="LineNr">1877 </span>    *op <span class="Special">&lt;-</span> merge <span class="Constant">2/delete-operation</span>, save-row/before, save-column/before, top-before, cursor-row/after, cursor-column/after, top-after, deleted-cell/deleted, before-cursor/delete-from, deleted-until, <span class="Constant">2/coalesce-delete</span>
-<span id="L1878" class="LineNr">1878 </span>    editor <span class="Special">&lt;-</span> <a href='012-editor-undo.mu.html#L200'>add-operation</a> editor, op
-<span id="L1879" class="LineNr">1879 </span><span class="Constant">    +done-adding-delete-operation</span>
+<span id="L1848" class="LineNr">1848 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> deleted-cell  <span class="Comment"># delete failed; don't add an undo operation</span>
+<span id="L1849" class="LineNr">1849 </span>  <span class="Conceal">¦</span> top-after:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
+<span id="L1850" class="LineNr">1850 </span>  <span class="Conceal">¦</span> cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
+<span id="L1851" class="LineNr">1851 </span>  <span class="Conceal">¦</span> cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
+<span id="L1852" class="LineNr">1852 </span>  <span class="Conceal">¦</span> before-cursor:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
+<span id="L1853" class="LineNr">1853 </span>  <span class="Conceal">¦</span> undo:&amp;:list:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">undo:offset</span>
+<span id="L1854" class="LineNr">1854 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L1855" class="LineNr">1855 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># if previous operation was an insert, coalesce this operation with it</span>
+<span id="L1856" class="LineNr">1856 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> undo
+<span id="L1857" class="LineNr">1857 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> first undo
+<span id="L1858" class="LineNr">1858 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion:<a href='012-editor-undo.mu.html#L41'>delete-operation</a>, is-delete?:bool <span class="Special">&lt;-</span> maybe-convert *op, <span class="Constant">delete:variant</span>
+<span id="L1859" class="LineNr">1859 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-delete?
+<span id="L1860" class="LineNr">1860 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> previous-coalesce-tag:num <span class="Special">&lt;-</span> get deletion, <span class="Constant">tag:offset</span>
+<span id="L1861" class="LineNr">1861 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> coalesce?:bool <span class="Special">&lt;-</span> equal previous-coalesce-tag, <span class="Constant">2/coalesce-delete</span>
+<span id="L1862" class="LineNr">1862 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> coalesce?
+<span id="L1863" class="LineNr">1863 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> delete-until:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L1864" class="LineNr">1864 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">delete-until:offset</span>, delete-until
+<span id="L1865" class="LineNr">1865 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deleted-so-far:&amp;:duplex-list:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">deleted-text:offset</span>
+<span id="L1866" class="LineNr">1866 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deleted-so-far <span class="Special">&lt;-</span> append deleted-so-far, deleted-cell
+<span id="L1867" class="LineNr">1867 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">deleted-text:offset</span>, deleted-so-far
+<span id="L1868" class="LineNr">1868 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">after-row:offset</span>, cursor-row
+<span id="L1869" class="LineNr">1869 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">after-column:offset</span>, cursor-column
+<span id="L1870" class="LineNr">1870 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">after-top-of-screen:offset</span>, top-after
+<span id="L1871" class="LineNr">1871 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> *op <span class="Special">&lt;-</span> merge <span class="Constant">2/delete-operation</span>, deletion
+<span id="L1872" class="LineNr">1872 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break</span> <span class="Constant">+done-adding-delete-operation</span>
+<span id="L1873" class="LineNr">1873 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L1874" class="LineNr">1874 </span>  <span class="Conceal">¦</span> <span class="Comment"># if not, create a new operation</span>
+<span id="L1875" class="LineNr">1875 </span>  <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> new <span class="Constant"><a href='012-editor-undo.mu.html#L5'>operation</a>:type</span>
+<span id="L1876" class="LineNr">1876 </span>  <span class="Conceal">¦</span> deleted-until:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L1877" class="LineNr">1877 </span>  <span class="Conceal">¦</span> *op <span class="Special">&lt;-</span> merge <span class="Constant">2/delete-operation</span>, save-row/before, save-column/before, top-before, cursor-row/after, cursor-column/after, top-after, deleted-cell/deleted, before-cursor/delete-from, deleted-until, <span class="Constant">2/coalesce-delete</span>
+<span id="L1878" class="LineNr">1878 </span>  <span class="Conceal">¦</span> editor <span class="Special">&lt;-</span> <a href='012-editor-undo.mu.html#L200'>add-operation</a> editor, op
+<span id="L1879" class="LineNr">1879 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> +done-adding-delete-operation</span>
 <span id="L1880" class="LineNr">1880 </span>  <span class="Delimiter">}</span>
 <span id="L1881" class="LineNr">1881 </span>]
 <span id="L1882" class="LineNr">1882 </span>
@@ -1953,77 +1954,77 @@ if ('onhashchange' in window) {
 <span id="L1892" class="LineNr">1892 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L1893" class="LineNr">1893 </span>  <span class="Comment"># insert some text and hit delete and backspace a few times</span>
 <span id="L1894" class="LineNr">1894 </span>  assume-console [
-<span id="L1895" class="LineNr">1895 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
-<span id="L1896" class="LineNr">1896 </span>    press ctrl-k
+<span id="L1895" class="LineNr">1895 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
+<span id="L1896" class="LineNr">1896 </span>  <span class="Conceal">¦</span> press ctrl-k
 <span id="L1897" class="LineNr">1897 </span>  ]
 <span id="L1898" class="LineNr">1898 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1899" class="LineNr">1899 </span>  screen-should-contain [
-<span id="L1900" class="LineNr">1900 </span>   <span class="Constant"> .          .</span>
-<span id="L1901" class="LineNr">1901 </span>   <span class="Constant"> .a         .</span>
-<span id="L1902" class="LineNr">1902 </span>   <span class="Constant"> .def       .</span>
-<span id="L1903" class="LineNr">1903 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1904" class="LineNr">1904 </span>   <span class="Constant"> .          .</span>
+<span id="L1900" class="LineNr">1900 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1901" class="LineNr">1901 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L1902" class="LineNr">1902 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
+<span id="L1903" class="LineNr">1903 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1904" class="LineNr">1904 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1905" class="LineNr">1905 </span>  ]
 <span id="L1906" class="LineNr">1906 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L1907" class="LineNr">1907 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1908" class="LineNr">1908 </span>  memory-should-contain [
-<span id="L1909" class="LineNr">1909 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1910" class="LineNr">1910 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1909" class="LineNr">1909 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1910" class="LineNr">1910 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L1911" class="LineNr">1911 </span>  ]
 <span id="L1912" class="LineNr">1912 </span>  <span class="Comment"># undo</span>
 <span id="L1913" class="LineNr">1913 </span>  assume-console [
-<span id="L1914" class="LineNr">1914 </span>    press ctrl-z
+<span id="L1914" class="LineNr">1914 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L1915" class="LineNr">1915 </span>  ]
 <span id="L1916" class="LineNr">1916 </span>  run [
-<span id="L1917" class="LineNr">1917 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1917" class="LineNr">1917 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1918" class="LineNr">1918 </span>  ]
 <span id="L1919" class="LineNr">1919 </span>  screen-should-contain [
-<span id="L1920" class="LineNr">1920 </span>   <span class="Constant"> .          .</span>
-<span id="L1921" class="LineNr">1921 </span>   <span class="Constant"> .abc       .</span>
-<span id="L1922" class="LineNr">1922 </span>   <span class="Constant"> .def       .</span>
-<span id="L1923" class="LineNr">1923 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1924" class="LineNr">1924 </span>   <span class="Constant"> .          .</span>
+<span id="L1920" class="LineNr">1920 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1921" class="LineNr">1921 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L1922" class="LineNr">1922 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
+<span id="L1923" class="LineNr">1923 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1924" class="LineNr">1924 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1925" class="LineNr">1925 </span>  ]
 <span id="L1926" class="LineNr">1926 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L1927" class="LineNr">1927 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1928" class="LineNr">1928 </span>  memory-should-contain [
-<span id="L1929" class="LineNr">1929 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1930" class="LineNr">1930 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1929" class="LineNr">1929 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1930" class="LineNr">1930 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L1931" class="LineNr">1931 </span>  ]
 <span id="L1932" class="LineNr">1932 </span>  <span class="Comment"># redo</span>
 <span id="L1933" class="LineNr">1933 </span>  assume-console [
-<span id="L1934" class="LineNr">1934 </span>    press ctrl-y
+<span id="L1934" class="LineNr">1934 </span>  <span class="Conceal">¦</span> press ctrl-y
 <span id="L1935" class="LineNr">1935 </span>  ]
 <span id="L1936" class="LineNr">1936 </span>  run [
-<span id="L1937" class="LineNr">1937 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1937" class="LineNr">1937 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1938" class="LineNr">1938 </span>  ]
 <span id="L1939" class="LineNr">1939 </span>  <span class="Comment"># first line inserted</span>
 <span id="L1940" class="LineNr">1940 </span>  screen-should-contain [
-<span id="L1941" class="LineNr">1941 </span>   <span class="Constant"> .          .</span>
-<span id="L1942" class="LineNr">1942 </span>   <span class="Constant"> .a         .</span>
-<span id="L1943" class="LineNr">1943 </span>   <span class="Constant"> .def       .</span>
-<span id="L1944" class="LineNr">1944 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1945" class="LineNr">1945 </span>   <span class="Constant"> .          .</span>
+<span id="L1941" class="LineNr">1941 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1942" class="LineNr">1942 </span>  <span class="Conceal">¦</span><span class="Constant"> .a         .</span>
+<span id="L1943" class="LineNr">1943 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
+<span id="L1944" class="LineNr">1944 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1945" class="LineNr">1945 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1946" class="LineNr">1946 </span>  ]
 <span id="L1947" class="LineNr">1947 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L1948" class="LineNr">1948 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L1949" class="LineNr">1949 </span>  memory-should-contain [
-<span id="L1950" class="LineNr">1950 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L1951" class="LineNr">1951 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1950" class="LineNr">1950 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L1951" class="LineNr">1951 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
 <span id="L1952" class="LineNr">1952 </span>  ]
 <span id="L1953" class="LineNr">1953 </span>  <span class="Comment"># cursor should be in the right place</span>
 <span id="L1954" class="LineNr">1954 </span>  assume-console [
-<span id="L1955" class="LineNr">1955 </span>    type <span class="Constant">[1]</span>
+<span id="L1955" class="LineNr">1955 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
 <span id="L1956" class="LineNr">1956 </span>  ]
 <span id="L1957" class="LineNr">1957 </span>  run [
-<span id="L1958" class="LineNr">1958 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L1958" class="LineNr">1958 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L1959" class="LineNr">1959 </span>  ]
 <span id="L1960" class="LineNr">1960 </span>  screen-should-contain [
-<span id="L1961" class="LineNr">1961 </span>   <span class="Constant"> .          .</span>
-<span id="L1962" class="LineNr">1962 </span>   <span class="Constant"> .a1        .</span>
-<span id="L1963" class="LineNr">1963 </span>   <span class="Constant"> .def       .</span>
-<span id="L1964" class="LineNr">1964 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L1965" class="LineNr">1965 </span>   <span class="Constant"> .          .</span>
+<span id="L1961" class="LineNr">1961 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L1962" class="LineNr">1962 </span>  <span class="Conceal">¦</span><span class="Constant"> .a1        .</span>
+<span id="L1963" class="LineNr">1963 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
+<span id="L1964" class="LineNr">1964 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L1965" class="LineNr">1965 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L1966" class="LineNr">1966 </span>  ]
 <span id="L1967" class="LineNr">1967 </span>]
 <span id="L1968" class="LineNr">1968 </span>
@@ -2032,15 +2033,15 @@ if ('onhashchange' in window) {
 <span id="L1971" class="LineNr">1971 </span>]
 <span id="L1972" class="LineNr">1972 </span><span class="muRecipe">before</span> <span class="Constant"><a href='003-shortcuts.mu.html#L1791'>&lt;delete-to-end-of-line-end&gt;</a></span> [
 <span id="L1973" class="LineNr">1973 </span>  <span class="Delimiter">{</span>
-<span id="L1974" class="LineNr">1974 </span>    <span class="muControl">break-unless</span> deleted-cells  <span class="Comment"># delete failed; don't add an undo operation</span>
-<span id="L1975" class="LineNr">1975 </span>    top-after:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
-<span id="L1976" class="LineNr">1976 </span>    cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
-<span id="L1977" class="LineNr">1977 </span>    cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
-<span id="L1978" class="LineNr">1978 </span>    deleted-until:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
-<span id="L1979" class="LineNr">1979 </span>    op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> new <span class="Constant"><a href='012-editor-undo.mu.html#L5'>operation</a>:type</span>
-<span id="L1980" class="LineNr">1980 </span>    *op <span class="Special">&lt;-</span> merge <span class="Constant">2/delete-operation</span>, save-row/before, save-column/before, top-before, cursor-row/after, cursor-column/after, top-after, deleted-cells/deleted, before-cursor/delete-from, deleted-until, <span class="Constant">0/never-coalesce</span>
-<span id="L1981" class="LineNr">1981 </span>    editor <span class="Special">&lt;-</span> <a href='012-editor-undo.mu.html#L200'>add-operation</a> editor, op
-<span id="L1982" class="LineNr">1982 </span><span class="Constant">    +done-adding-delete-operation</span>
+<span id="L1974" class="LineNr">1974 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> deleted-cells  <span class="Comment"># delete failed; don't add an undo operation</span>
+<span id="L1975" class="LineNr">1975 </span>  <span class="Conceal">¦</span> top-after:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
+<span id="L1976" class="LineNr">1976 </span>  <span class="Conceal">¦</span> cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
+<span id="L1977" class="LineNr">1977 </span>  <span class="Conceal">¦</span> cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
+<span id="L1978" class="LineNr">1978 </span>  <span class="Conceal">¦</span> deleted-until:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L1979" class="LineNr">1979 </span>  <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> new <span class="Constant"><a href='012-editor-undo.mu.html#L5'>operation</a>:type</span>
+<span id="L1980" class="LineNr">1980 </span>  <span class="Conceal">¦</span> *op <span class="Special">&lt;-</span> merge <span class="Constant">2/delete-operation</span>, save-row/before, save-column/before, top-before, cursor-row/after, cursor-column/after, top-after, deleted-cells/deleted, before-cursor/delete-from, deleted-until, <span class="Constant">0/never-coalesce</span>
+<span id="L1981" class="LineNr">1981 </span>  <span class="Conceal">¦</span> editor <span class="Special">&lt;-</span> <a href='012-editor-undo.mu.html#L200'>add-operation</a> editor, op
+<span id="L1982" class="LineNr">1982 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> +done-adding-delete-operation</span>
 <span id="L1983" class="LineNr">1983 </span>  <span class="Delimiter">}</span>
 <span id="L1984" class="LineNr">1984 </span>]
 <span id="L1985" class="LineNr">1985 </span>
@@ -2056,77 +2057,77 @@ if ('onhashchange' in window) {
 <span id="L1995" class="LineNr">1995 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L1996" class="LineNr">1996 </span>  <span class="Comment"># insert some text and hit delete and backspace a few times</span>
 <span id="L1997" class="LineNr">1997 </span>  assume-console [
-<span id="L1998" class="LineNr">1998 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 2</span>
-<span id="L1999" class="LineNr">1999 </span>    press ctrl-u
+<span id="L1998" class="LineNr">1998 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 1</span>,<span class="Constant"> 2</span>
+<span id="L1999" class="LineNr">1999 </span>  <span class="Conceal">¦</span> press ctrl-u
 <span id="L2000" class="LineNr">2000 </span>  ]
 <span id="L2001" class="LineNr">2001 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2002" class="LineNr">2002 </span>  screen-should-contain [
-<span id="L2003" class="LineNr">2003 </span>   <span class="Constant"> .          .</span>
-<span id="L2004" class="LineNr">2004 </span>   <span class="Constant"> .c         .</span>
-<span id="L2005" class="LineNr">2005 </span>   <span class="Constant"> .def       .</span>
-<span id="L2006" class="LineNr">2006 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L2007" class="LineNr">2007 </span>   <span class="Constant"> .          .</span>
+<span id="L2003" class="LineNr">2003 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2004" class="LineNr">2004 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
+<span id="L2005" class="LineNr">2005 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
+<span id="L2006" class="LineNr">2006 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L2007" class="LineNr">2007 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L2008" class="LineNr">2008 </span>  ]
 <span id="L2009" class="LineNr">2009 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L2010" class="LineNr">2010 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L2011" class="LineNr">2011 </span>  memory-should-contain [
-<span id="L2012" class="LineNr">2012 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L2013" class="LineNr">2013 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
+<span id="L2012" class="LineNr">2012 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L2013" class="LineNr">2013 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
 <span id="L2014" class="LineNr">2014 </span>  ]
 <span id="L2015" class="LineNr">2015 </span>  <span class="Comment"># undo</span>
 <span id="L2016" class="LineNr">2016 </span>  assume-console [
-<span id="L2017" class="LineNr">2017 </span>    press ctrl-z
+<span id="L2017" class="LineNr">2017 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L2018" class="LineNr">2018 </span>  ]
 <span id="L2019" class="LineNr">2019 </span>  run [
-<span id="L2020" class="LineNr">2020 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2020" class="LineNr">2020 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2021" class="LineNr">2021 </span>  ]
 <span id="L2022" class="LineNr">2022 </span>  screen-should-contain [
-<span id="L2023" class="LineNr">2023 </span>   <span class="Constant"> .          .</span>
-<span id="L2024" class="LineNr">2024 </span>   <span class="Constant"> .abc       .</span>
-<span id="L2025" class="LineNr">2025 </span>   <span class="Constant"> .def       .</span>
-<span id="L2026" class="LineNr">2026 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L2027" class="LineNr">2027 </span>   <span class="Constant"> .          .</span>
+<span id="L2023" class="LineNr">2023 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2024" class="LineNr">2024 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L2025" class="LineNr">2025 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
+<span id="L2026" class="LineNr">2026 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L2027" class="LineNr">2027 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L2028" class="LineNr">2028 </span>  ]
 <span id="L2029" class="LineNr">2029 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L2030" class="LineNr">2030 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L2031" class="LineNr">2031 </span>  memory-should-contain [
-<span id="L2032" class="LineNr">2032 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L2033" class="LineNr">2033 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
+<span id="L2032" class="LineNr">2032 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L2033" class="LineNr">2033 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
 <span id="L2034" class="LineNr">2034 </span>  ]
 <span id="L2035" class="LineNr">2035 </span>  <span class="Comment"># redo</span>
 <span id="L2036" class="LineNr">2036 </span>  assume-console [
-<span id="L2037" class="LineNr">2037 </span>    press ctrl-y
+<span id="L2037" class="LineNr">2037 </span>  <span class="Conceal">¦</span> press ctrl-y
 <span id="L2038" class="LineNr">2038 </span>  ]
 <span id="L2039" class="LineNr">2039 </span>  run [
-<span id="L2040" class="LineNr">2040 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2040" class="LineNr">2040 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2041" class="LineNr">2041 </span>  ]
 <span id="L2042" class="LineNr">2042 </span>  <span class="Comment"># first line inserted</span>
 <span id="L2043" class="LineNr">2043 </span>  screen-should-contain [
-<span id="L2044" class="LineNr">2044 </span>   <span class="Constant"> .          .</span>
-<span id="L2045" class="LineNr">2045 </span>   <span class="Constant"> .c         .</span>
-<span id="L2046" class="LineNr">2046 </span>   <span class="Constant"> .def       .</span>
-<span id="L2047" class="LineNr">2047 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L2048" class="LineNr">2048 </span>   <span class="Constant"> .          .</span>
+<span id="L2044" class="LineNr">2044 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2045" class="LineNr">2045 </span>  <span class="Conceal">¦</span><span class="Constant"> .c         .</span>
+<span id="L2046" class="LineNr">2046 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
+<span id="L2047" class="LineNr">2047 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L2048" class="LineNr">2048 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L2049" class="LineNr">2049 </span>  ]
 <span id="L2050" class="LineNr">2050 </span>  3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
 <span id="L2051" class="LineNr">2051 </span>  4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
 <span id="L2052" class="LineNr">2052 </span>  memory-should-contain [
-<span id="L2053" class="LineNr">2053 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
-<span id="L2054" class="LineNr">2054 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
+<span id="L2053" class="LineNr">2053 </span>  <span class="Conceal">¦</span><span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
+<span id="L2054" class="LineNr">2054 </span>  <span class="Conceal">¦</span><span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
 <span id="L2055" class="LineNr">2055 </span>  ]
 <span id="L2056" class="LineNr">2056 </span>  <span class="Comment"># cursor should be in the right place</span>
 <span id="L2057" class="LineNr">2057 </span>  assume-console [
-<span id="L2058" class="LineNr">2058 </span>    type <span class="Constant">[1]</span>
+<span id="L2058" class="LineNr">2058 </span>  <span class="Conceal">¦</span> type <span class="Constant">[1]</span>
 <span id="L2059" class="LineNr">2059 </span>  ]
 <span id="L2060" class="LineNr">2060 </span>  run [
-<span id="L2061" class="LineNr">2061 </span>    <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
+<span id="L2061" class="LineNr">2061 </span>  <span class="Conceal">¦</span> <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2062" class="LineNr">2062 </span>  ]
 <span id="L2063" class="LineNr">2063 </span>  screen-should-contain [
-<span id="L2064" class="LineNr">2064 </span>   <span class="Constant"> .          .</span>
-<span id="L2065" class="LineNr">2065 </span>   <span class="Constant"> .1c        .</span>
-<span id="L2066" class="LineNr">2066 </span>   <span class="Constant"> .def       .</span>
-<span id="L2067" class="LineNr">2067 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L2068" class="LineNr">2068 </span>   <span class="Constant"> .          .</span>
+<span id="L2064" class="LineNr">2064 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2065" class="LineNr">2065 </span>  <span class="Conceal">¦</span><span class="Constant"> .1c        .</span>
+<span id="L2066" class="LineNr">2066 </span>  <span class="Conceal">¦</span><span class="Constant"> .def       .</span>
+<span id="L2067" class="LineNr">2067 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L2068" class="LineNr">2068 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L2069" class="LineNr">2069 </span>  ]
 <span id="L2070" class="LineNr">2070 </span>]
 <span id="L2071" class="LineNr">2071 </span>
@@ -2135,16 +2136,16 @@ if ('onhashchange' in window) {
 <span id="L2074" class="LineNr">2074 </span>]
 <span id="L2075" class="LineNr">2075 </span><span class="muRecipe">before</span> <span class="Constant"><a href='003-shortcuts.mu.html#L1654'>&lt;delete-to-start-of-line-end&gt;</a></span> [
 <span id="L2076" class="LineNr">2076 </span>  <span class="Delimiter">{</span>
-<span id="L2077" class="LineNr">2077 </span>    <span class="muControl">break-unless</span> deleted-cells  <span class="Comment"># delete failed; don't add an undo operation</span>
-<span id="L2078" class="LineNr">2078 </span>    top-after:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
-<span id="L2079" class="LineNr">2079 </span>    op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> new <span class="Constant"><a href='012-editor-undo.mu.html#L5'>operation</a>:type</span>
-<span id="L2080" class="LineNr">2080 </span>    before-cursor:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
-<span id="L2081" class="LineNr">2081 </span>    deleted-until:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
-<span id="L2082" class="LineNr">2082 </span>    cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
-<span id="L2083" class="LineNr">2083 </span>    cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
-<span id="L2084" class="LineNr">2084 </span>    *op <span class="Special">&lt;-</span> merge <span class="Constant">2/delete-operation</span>, save-row/before, save-column/before, top-before, cursor-row/after, cursor-column/after, top-after, deleted-cells/deleted, before-cursor/delete-from, deleted-until, <span class="Constant">0/never-coalesce</span>
-<span id="L2085" class="LineNr">2085 </span>    editor <span class="Special">&lt;-</span> <a href='012-editor-undo.mu.html#L200'>add-operation</a> editor, op
-<span id="L2086" class="LineNr">2086 </span><span class="Constant">    +done-adding-delete-operation</span>
+<span id="L2077" class="LineNr">2077 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> deleted-cells  <span class="Comment"># delete failed; don't add an undo operation</span>
+<span id="L2078" class="LineNr">2078 </span>  <span class="Conceal">¦</span> top-after:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
+<span id="L2079" class="LineNr">2079 </span>  <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> new <span class="Constant"><a href='012-editor-undo.mu.html#L5'>operation</a>:type</span>
+<span id="L2080" class="LineNr">2080 </span>  <span class="Conceal">¦</span> before-cursor:&amp;:duplex-list:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
+<span id="L2081" class="LineNr">2081 </span>  <span class="Conceal">¦</span> deleted-until:&amp;:duplex-list:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L2082" class="LineNr">2082 </span>  <span class="Conceal">¦</span> cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
+<span id="L2083" class="LineNr">2083 </span>  <span class="Conceal">¦</span> cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
+<span id="L2084" class="LineNr">2084 </span>  <span class="Conceal">¦</span> *op <span class="Special">&lt;-</span> merge <span class="Constant">2/delete-operation</span>, save-row/before, save-column/before, top-before, cursor-row/after, cursor-column/after, top-after, deleted-cells/deleted, before-cursor/delete-from, deleted-until, <span class="Constant">0/never-coalesce</span>
+<span id="L2085" class="LineNr">2085 </span>  <span class="Conceal">¦</span> editor <span class="Special">&lt;-</span> <a href='012-editor-undo.mu.html#L200'>add-operation</a> editor, op
+<span id="L2086" class="LineNr">2086 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> +done-adding-delete-operation</span>
 <span id="L2087" class="LineNr">2087 </span>  <span class="Delimiter">}</span>
 <span id="L2088" class="LineNr">2088 </span>]
 <span id="L2089" class="LineNr">2089 </span>
@@ -2156,16 +2157,16 @@ if ('onhashchange' in window) {
 <span id="L2095" class="LineNr">2095 </span>  <a href='002-typing.mu.html#L263'>editor-render</a> <a href='../081print.mu.html#L4'>screen</a>, e
 <span id="L2096" class="LineNr">2096 </span>  <span class="Comment"># insert some text and hit delete and backspace a few times</span>
 <span id="L2097" class="LineNr">2097 </span>  assume-console [
-<span id="L2098" class="LineNr">2098 </span>    type <span class="Constant">[abc]</span>
-<span id="L2099" class="LineNr">2099 </span>    press ctrl-u
-<span id="L2100" class="LineNr">2100 </span>    press ctrl-z
+<span id="L2098" class="LineNr">2098 </span>  <span class="Conceal">¦</span> type <span class="Constant">[abc]</span>
+<span id="L2099" class="LineNr">2099 </span>  <span class="Conceal">¦</span> press ctrl-u
+<span id="L2100" class="LineNr">2100 </span>  <span class="Conceal">¦</span> press ctrl-z
 <span id="L2101" class="LineNr">2101 </span>  ]
 <span id="L2102" class="LineNr">2102 </span>  <a href='002-typing.mu.html#L14'>editor-event-loop</a> <a href='../081print.mu.html#L4'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
 <span id="L2103" class="LineNr">2103 </span>  screen-should-contain [
-<span id="L2104" class="LineNr">2104 </span>   <span class="Constant"> .          .</span>
-<span id="L2105" class="LineNr">2105 </span>   <span class="Constant"> .abc       .</span>
-<span id="L2106" class="LineNr">2106 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
-<span id="L2107" class="LineNr">2107 </span>   <span class="Constant"> .          .</span>
+<span id="L2104" class="LineNr">2104 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
+<span id="L2105" class="LineNr">2105 </span>  <span class="Conceal">¦</span><span class="Constant"> .abc       .</span>
+<span id="L2106" class="LineNr">2106 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌.</span>
+<span id="L2107" class="LineNr">2107 </span>  <span class="Conceal">¦</span><span class="Constant"> .          .</span>
 <span id="L2108" class="LineNr">2108 </span>  ]
 <span id="L2109" class="LineNr">2109 </span>]
 </pre>