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<a href='https://github.com/akkartik/mu/blob/master/edit/003-shortcuts.mu'>https://github.com/akkartik/mu/blob/master/edit/003-shortcuts.mu</a>
<pre id='vimCodeElement'>
<span id="L1" class="LineNr">   1 </span><span class="SalientComment">## special shortcuts for manipulating the editor</span>
<span id="L2" class="LineNr">   2 </span><span class="Comment"># Some keys on the keyboard generate unicode characters, others generate</span>
<span id="L3" class="LineNr">   3 </span><span class="Comment"># terminfo key codes. We need to modify different places in the two cases.</span>
<span id="L4" class="LineNr">   4 </span>
<span id="L5" class="LineNr">   5 </span><span class="Comment"># tab - insert two spaces</span>
<span id="L6" class="LineNr">   6 </span>
<span id="L7" class="LineNr">   7 </span><span class="muScenario">scenario</span> editor-inserts-two-spaces-on-tab [
<span id="L8" class="LineNr">   8 </span>  <span class="Constant">local-scope</span>
<span id="L9" class="LineNr">   9 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L10" class="LineNr">  10 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[ab</span>
<span id="L11" class="LineNr">  11 </span><span class="Constant">cd]</span>
<span id="L12" class="LineNr">  12 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L13" class="LineNr">  13 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L14" class="LineNr">  14 </span>  $clear-trace
<span id="L15" class="LineNr">  15 </span>  assume-console [
<span id="L16" class="LineNr">  16 </span>    press tab
<span id="L17" class="LineNr">  17 </span>  ]
<span id="L18" class="LineNr">  18 </span>  run [
<span id="L19" class="LineNr">  19 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L20" class="LineNr">  20 </span>  ]
<span id="L21" class="LineNr">  21 </span>  screen-should-contain [
<span id="L22" class="LineNr">  22 </span>   <span class="Constant"> .          .</span>
<span id="L23" class="LineNr">  23 </span>   <span class="Constant"> .  ab      .</span>
<span id="L24" class="LineNr">  24 </span>   <span class="Constant"> .cd        .</span>
<span id="L25" class="LineNr">  25 </span>  ]
<span id="L26" class="LineNr">  26 </span>  <span class="Comment"># we render at most two editor rows worth (one row for each space)</span>
<span id="L27" class="LineNr">  27 </span>  check-trace-count-for-label-lesser-than<span class="Constant"> 10</span>, <span class="Constant">[print-character]</span>
<span id="L28" class="LineNr">  28 </span>]
<span id="L29" class="LineNr">  29 </span>
<span id="L30" class="LineNr">  30 </span><span class="muScenario">scenario</span> editor-inserts-two-spaces-and-wraps-line-on-tab [
<span id="L31" class="LineNr">  31 </span>  <span class="Constant">local-scope</span>
<span id="L32" class="LineNr">  32 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L33" class="LineNr">  33 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abcd]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L34" class="LineNr">  34 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L35" class="LineNr">  35 </span>  $clear-trace
<span id="L36" class="LineNr">  36 </span>  assume-console [
<span id="L37" class="LineNr">  37 </span>    press tab
<span id="L38" class="LineNr">  38 </span>  ]
<span id="L39" class="LineNr">  39 </span>  run [
<span id="L40" class="LineNr">  40 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L41" class="LineNr">  41 </span>  ]
<span id="L42" class="LineNr">  42 </span>  screen-should-contain [
<span id="L43" class="LineNr">  43 </span>   <span class="Constant"> .          .</span>
<span id="L44" class="LineNr">  44 </span>   <span class="Constant"> .  ab↩     .</span>
<span id="L45" class="LineNr">  45 </span>   <span class="Constant"> .cd        .</span>
<span id="L46" class="LineNr">  46 </span>  ]
<span id="L47" class="LineNr">  47 </span>  <span class="Comment"># we re-render the whole editor</span>
<span id="L48" class="LineNr">  48 </span>  check-trace-count-for-label-greater-than<span class="Constant"> 10</span>, <span class="Constant">[print-character]</span>
<span id="L49" class="LineNr">  49 </span>]
<span id="L50" class="LineNr">  50 </span>
<span id="L51" class="LineNr">  51 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L52" class="LineNr">  52 </span>  <span class="Delimiter">{</span>
<span id="L53" class="LineNr">  53 </span>    tab?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">9/tab</span>
<span id="L54" class="LineNr">  54 </span>    <span class="muControl">break-unless</span> tab?
<span id="L55" class="LineNr">  55 </span><span class="Constant">    &lt;begin-insert-character&gt;</span>
<span id="L56" class="LineNr">  56 </span>    <span class="Comment"># todo: decompose insert-at-cursor into editor update and screen update,</span>
<span id="L57" class="LineNr">  57 </span>    <span class="Comment"># so that 'tab' doesn't render the current line multiple times</span>
<span id="L58" class="LineNr">  58 </span>    <a href='002-typing.mu.html#L203'>insert-at-cursor</a> editor, <span class="Constant">32/space</span>, <a href='../081print.mu.html#L16'>screen</a>
<span id="L59" class="LineNr">  59 </span>    go-render? <span class="Special">&lt;-</span> <a href='002-typing.mu.html#L203'>insert-at-cursor</a> editor, <span class="Constant">32/space</span>, <a href='../081print.mu.html#L16'>screen</a>
<span id="L60" class="LineNr">  60 </span><span class="Constant">    &lt;end-insert-character&gt;</span>
<span id="L61" class="LineNr">  61 </span>   <span class="muControl"> return</span>
<span id="L62" class="LineNr">  62 </span>  <span class="Delimiter">}</span>
<span id="L63" class="LineNr">  63 </span>]
<span id="L64" class="LineNr">  64 </span>
<span id="L65" class="LineNr">  65 </span><span class="Comment"># backspace - delete character before cursor</span>
<span id="L66" class="LineNr">  66 </span>
<span id="L67" class="LineNr">  67 </span><span class="muScenario">scenario</span> editor-handles-backspace-key [
<span id="L68" class="LineNr">  68 </span>  <span class="Constant">local-scope</span>
<span id="L69" class="LineNr">  69 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L70" class="LineNr">  70 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abc]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L71" class="LineNr">  71 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L72" class="LineNr">  72 </span>  $clear-trace
<span id="L73" class="LineNr">  73 </span>  assume-console [
<span id="L74" class="LineNr">  74 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
<span id="L75" class="LineNr">  75 </span>    press backspace
<span id="L76" class="LineNr">  76 </span>  ]
<span id="L77" class="LineNr">  77 </span>  run [
<span id="L78" class="LineNr">  78 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L79" class="LineNr">  79 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L80" class="LineNr">  80 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L81" class="LineNr">  81 </span>  ]
<span id="L82" class="LineNr">  82 </span>  screen-should-contain [
<span id="L83" class="LineNr">  83 </span>   <span class="Constant"> .          .</span>
<span id="L84" class="LineNr">  84 </span>   <span class="Constant"> .bc        .</span>
<span id="L85" class="LineNr">  85 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L86" class="LineNr">  86 </span>   <span class="Constant"> .          .</span>
<span id="L87" class="LineNr">  87 </span>  ]
<span id="L88" class="LineNr">  88 </span>  memory-should-contain [
<span id="L89" class="LineNr">  89 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L90" class="LineNr">  90 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L91" class="LineNr">  91 </span>  ]
<span id="L92" class="LineNr">  92 </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="L93" class="LineNr">  93 </span>]
<span id="L94" class="LineNr">  94 </span>
<span id="L95" class="LineNr">  95 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L96" class="LineNr">  96 </span>  <span class="Delimiter">{</span>
<span id="L97" class="LineNr">  97 </span>    delete-previous-character?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">8/backspace</span>
<span id="L98" class="LineNr">  98 </span>    <span class="muControl">break-unless</span> delete-previous-character?
<span id="L99" class="LineNr">  99 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L99'>&lt;begin-backspace-character&gt;</a></span>
<span id="L100" class="LineNr"> 100 </span>    go-render?:bool, backspaced-cell:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L109'>delete-before-cursor</a> editor, <a href='../081print.mu.html#L16'>screen</a>
<span id="L101" class="LineNr"> 101 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L101'>&lt;end-backspace-character&gt;</a></span>
<span id="L102" class="LineNr"> 102 </span>   <span class="muControl"> return</span>
<span id="L103" class="LineNr"> 103 </span>  <span class="Delimiter">}</span>
<span id="L104" class="LineNr"> 104 </span>]
<span id="L105" class="LineNr"> 105 </span>
<span id="L106" class="LineNr"> 106 </span><span class="Comment"># return values:</span>
<span id="L107" class="LineNr"> 107 </span><span class="Comment">#   go-render? - whether caller needs to update the screen</span>
<span id="L108" class="LineNr"> 108 </span><span class="Comment">#   backspaced-cell - value deleted (or 0 if nothing was deleted) so we can save it for undo, etc.</span>
<span id="L109" class="LineNr"> 109 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L109'>delete-before-cursor</a> editor:&amp;:editor, <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a><span class="muRecipe"> -&gt; </span>go-render?:bool, backspaced-cell:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char, editor:&amp;:editor, <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a> [
<span id="L110" class="LineNr"> 110 </span>  <span class="Constant">local-scope</span>
<span id="L111" class="LineNr"> 111 </span>  <span class="Constant">load-inputs</span>
<span id="L112" class="LineNr"> 112 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L113" class="LineNr"> 113 </span>  data:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
<span id="L114" class="LineNr"> 114 </span>  <span class="Comment"># if at start of text (before-cursor at § sentinel), return</span>
<span id="L115" class="LineNr"> 115 </span>  <a href='../065duplex_list.mu.html#L38'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L38'>prev</a> before-cursor
<span id="L116" class="LineNr"> 116 </span>  <span class="muControl">return-unless</span> <a href='../065duplex_list.mu.html#L38'>prev</a>,<span class="Constant"> false/no-more-render, null/nothing-deleted</span>
<span id="L117" class="LineNr"> 117 </span>  trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[delete-before-cursor]</span>
<span id="L118" class="LineNr"> 118 </span>  original-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L119" class="LineNr"> 119 </span>  scroll?:bool <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L156'>move-cursor-coordinates-left</a> editor
<span id="L120" class="LineNr"> 120 </span>  backspaced-cell:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy before-cursor
<span id="L121" class="LineNr"> 121 </span>  data <span class="Special">&lt;-</span> remove before-cursor, data  <span class="Comment"># will also neatly trim next/prev pointers in backspaced-cell/before-cursor</span>
<span id="L122" class="LineNr"> 122 </span>  before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L38'>prev</a>
<span id="L123" class="LineNr"> 123 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L124" class="LineNr"> 124 </span>  <span class="muControl">return-if</span> scroll?,<span class="Constant"> true/go-render</span>
<span id="L125" class="LineNr"> 125 </span>  <a href='../081print.mu.html#L768'>screen-width</a>:num <span class="Special">&lt;-</span> <a href='../081print.mu.html#L768'>screen-width</a> <a href='../081print.mu.html#L16'>screen</a>
<span id="L126" class="LineNr"> 126 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L127" class="LineNr"> 127 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L128" class="LineNr"> 128 </span>  <span class="Comment"># did we just backspace over a newline?</span>
<span id="L129" class="LineNr"> 129 </span>  same-row?:bool <span class="Special">&lt;-</span> equal cursor-row, original-row
<span id="L130" class="LineNr"> 130 </span>  <span class="muControl">return-unless</span> same-row?,<span class="Constant"> true/go-render</span>
<span id="L131" class="LineNr"> 131 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L132" class="LineNr"> 132 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L133" class="LineNr"> 133 </span>  curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-cursor
<span id="L134" class="LineNr"> 134 </span>  <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> move-cursor <a href='../081print.mu.html#L16'>screen</a>, cursor-row, cursor-column
<span id="L135" class="LineNr"> 135 </span>  curr-column:num <span class="Special">&lt;-</span> copy cursor-column
<span id="L136" class="LineNr"> 136 </span>  <span class="Delimiter">{</span>
<span id="L137" class="LineNr"> 137 </span>    <span class="Comment"># hit right margin? give up and let caller render</span>
<span id="L138" class="LineNr"> 138 </span>    at-right?:bool <span class="Special">&lt;-</span> greater-or-equal curr-column, right
<span id="L139" class="LineNr"> 139 </span>    <span class="muControl">return-if</span> at-right?,<span class="Constant"> true/go-render</span>
<span id="L140" class="LineNr"> 140 </span>    <span class="muControl">break-unless</span> curr
<span id="L141" class="LineNr"> 141 </span>    <span class="Comment"># newline? done.</span>
<span id="L142" class="LineNr"> 142 </span>    currc:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
<span id="L143" class="LineNr"> 143 </span>    at-newline?:bool <span class="Special">&lt;-</span> equal currc, <span class="Constant">10/newline</span>
<span id="L144" class="LineNr"> 144 </span>    <span class="muControl">break-if</span> at-newline?
<span id="L145" class="LineNr"> 145 </span>    <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> print <a href='../081print.mu.html#L16'>screen</a>, currc
<span id="L146" class="LineNr"> 146 </span>    curr-column <span class="Special">&lt;-</span> add curr-column,<span class="Constant"> 1</span>
<span id="L147" class="LineNr"> 147 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> curr
<span id="L148" class="LineNr"> 148 </span>   <span class="muControl"> loop</span>
<span id="L149" class="LineNr"> 149 </span>  <span class="Delimiter">}</span>
<span id="L150" class="LineNr"> 150 </span>  <span class="Comment"># we're guaranteed not to be at the right margin</span>
<span id="L151" class="LineNr"> 151 </span>  space:char <span class="Special">&lt;-</span> copy <span class="Constant">32/space</span>
<span id="L152" class="LineNr"> 152 </span>  <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> print <a href='../081print.mu.html#L16'>screen</a>, space
<span id="L153" class="LineNr"> 153 </span>  go-render? <span class="Special">&lt;-</span> copy<span class="Constant"> false</span>
<span id="L154" class="LineNr"> 154 </span>]
<span id="L155" class="LineNr"> 155 </span>
<span id="L156" class="LineNr"> 156 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L156'>move-cursor-coordinates-left</a> editor:&amp;:editor<span class="muRecipe"> -&gt; </span>go-render?:bool, editor:&amp;:editor [
<span id="L157" class="LineNr"> 157 </span>  <span class="Constant">local-scope</span>
<span id="L158" class="LineNr"> 158 </span>  <span class="Constant">load-inputs</span>
<span id="L159" class="LineNr"> 159 </span>  go-render?:bool <span class="Special">&lt;-</span> copy<span class="Constant"> false</span>
<span id="L160" class="LineNr"> 160 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L161" class="LineNr"> 161 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L162" class="LineNr"> 162 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L163" class="LineNr"> 163 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L164" class="LineNr"> 164 </span>  <span class="Comment"># if not at left margin, move one character left</span>
<span id="L165" class="LineNr"> 165 </span>  <span class="Delimiter">{</span>
<span id="L166" class="LineNr"> 166 </span>    at-left-margin?:bool <span class="Special">&lt;-</span> equal cursor-column, left
<span id="L167" class="LineNr"> 167 </span>    <span class="muControl">break-if</span> at-left-margin?
<span id="L168" class="LineNr"> 168 </span>    trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[decrementing cursor column]</span>
<span id="L169" class="LineNr"> 169 </span>    cursor-column <span class="Special">&lt;-</span> subtract cursor-column,<span class="Constant"> 1</span>
<span id="L170" class="LineNr"> 170 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L171" class="LineNr"> 171 </span>   <span class="muControl"> return</span>
<span id="L172" class="LineNr"> 172 </span>  <span class="Delimiter">}</span>
<span id="L173" class="LineNr"> 173 </span>  <span class="Comment"># if at left margin, we must move to previous row:</span>
<span id="L174" class="LineNr"> 174 </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="L175" class="LineNr"> 175 </span>  <span class="Delimiter">{</span>
<span id="L176" class="LineNr"> 176 </span>    <span class="muControl">break-if</span> top-of-screen?
<span id="L177" class="LineNr"> 177 </span>    cursor-row <span class="Special">&lt;-</span> subtract cursor-row,<span class="Constant"> 1</span>
<span id="L178" class="LineNr"> 178 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
<span id="L179" class="LineNr"> 179 </span>  <span class="Delimiter">}</span>
<span id="L180" class="LineNr"> 180 </span>  <span class="Delimiter">{</span>
<span id="L181" class="LineNr"> 181 </span>    <span class="muControl">break-unless</span> top-of-screen?
<span id="L182" class="LineNr"> 182 </span><span class="Constant">    &lt;scroll-up&gt;</span>
<span id="L183" class="LineNr"> 183 </span>    go-render? <span class="Special">&lt;-</span> copy<span class="Constant"> true</span>
<span id="L184" class="LineNr"> 184 </span>  <span class="Delimiter">}</span>
<span id="L185" class="LineNr"> 185 </span>  <span class="Delimiter">{</span>
<span id="L186" class="LineNr"> 186 </span>    <span class="Comment"># case 1: if previous character was newline, figure out how long the previous line is</span>
<span id="L187" class="LineNr"> 187 </span>    previous-character:char <span class="Special">&lt;-</span> get *before-cursor, <span class="Constant">value:offset</span>
<span id="L188" class="LineNr"> 188 </span>    previous-character-is-newline?:bool <span class="Special">&lt;-</span> equal previous-character, <span class="Constant">10/newline</span>
<span id="L189" class="LineNr"> 189 </span>    <span class="muControl">break-unless</span> previous-character-is-newline?
<span id="L190" class="LineNr"> 190 </span>    <span class="Comment"># compute length of previous line</span>
<span id="L191" class="LineNr"> 191 </span>    trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[switching to previous line]</span>
<span id="L192" class="LineNr"> 192 </span>    d:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
<span id="L193" class="LineNr"> 193 </span>    end-of-line:num <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L219'>previous-line-length</a> before-cursor, d
<span id="L194" class="LineNr"> 194 </span>    right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L195" class="LineNr"> 195 </span>    width:num <span class="Special">&lt;-</span> subtract right, left
<span id="L196" class="LineNr"> 196 </span>    wrap?:bool <span class="Special">&lt;-</span> greater-than end-of-line, width
<span id="L197" class="LineNr"> 197 </span>    <span class="Delimiter">{</span>
<span id="L198" class="LineNr"> 198 </span>      <span class="muControl">break-unless</span> wrap?
<span id="L199" class="LineNr"> 199 </span>      _, column-offset:num <span class="Special">&lt;-</span> divide-with-remainder end-of-line, width
<span id="L200" class="LineNr"> 200 </span>      cursor-column <span class="Special">&lt;-</span> add left, column-offset
<span id="L201" class="LineNr"> 201 </span>      *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L202" class="LineNr"> 202 </span>    <span class="Delimiter">}</span>
<span id="L203" class="LineNr"> 203 </span>    <span class="Delimiter">{</span>
<span id="L204" class="LineNr"> 204 </span>      <span class="muControl">break-if</span> wrap?
<span id="L205" class="LineNr"> 205 </span>      cursor-column <span class="Special">&lt;-</span> add left, end-of-line
<span id="L206" class="LineNr"> 206 </span>      *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L207" class="LineNr"> 207 </span>    <span class="Delimiter">}</span>
<span id="L208" class="LineNr"> 208 </span>   <span class="muControl"> return</span>
<span id="L209" class="LineNr"> 209 </span>  <span class="Delimiter">}</span>
<span id="L210" class="LineNr"> 210 </span>  <span class="Comment"># case 2: if previous-character was not newline, we're just at a wrapped line</span>
<span id="L211" class="LineNr"> 211 </span>  trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[wrapping to previous line]</span>
<span id="L212" class="LineNr"> 212 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L213" class="LineNr"> 213 </span>  cursor-column <span class="Special">&lt;-</span> subtract right,<span class="Constant"> 1</span>  <span class="Comment"># leave room for wrap icon</span>
<span id="L214" class="LineNr"> 214 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L215" class="LineNr"> 215 </span>]
<span id="L216" class="LineNr"> 216 </span>
<span id="L217" class="LineNr"> 217 </span><span class="Comment"># takes a pointer 'curr' into the doubly-linked list and its sentinel, counts</span>
<span id="L218" class="LineNr"> 218 </span><span class="Comment"># the length of the previous line before the 'curr' pointer.</span>
<span id="L219" class="LineNr"> 219 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L219'>previous-line-length</a> curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char, start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char<span class="muRecipe"> -&gt; </span>result:num [
<span id="L220" class="LineNr"> 220 </span>  <span class="Constant">local-scope</span>
<span id="L221" class="LineNr"> 221 </span>  <span class="Constant">load-inputs</span>
<span id="L222" class="LineNr"> 222 </span>  result:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
<span id="L223" class="LineNr"> 223 </span>  <span class="muControl">return-unless</span> curr
<span id="L224" class="LineNr"> 224 </span>  at-start?:bool <span class="Special">&lt;-</span> equal curr, start
<span id="L225" class="LineNr"> 225 </span>  <span class="muControl">return-if</span> at-start?
<span id="L226" class="LineNr"> 226 </span>  <span class="Delimiter">{</span>
<span id="L227" class="LineNr"> 227 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L38'>prev</a> curr
<span id="L228" class="LineNr"> 228 </span>    <span class="muControl">break-unless</span> curr
<span id="L229" class="LineNr"> 229 </span>    at-start?:bool <span class="Special">&lt;-</span> equal curr, start
<span id="L230" class="LineNr"> 230 </span>    <span class="muControl">break-if</span> at-start?
<span id="L231" class="LineNr"> 231 </span>    c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
<span id="L232" class="LineNr"> 232 </span>    at-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
<span id="L233" class="LineNr"> 233 </span>    <span class="muControl">break-if</span> at-newline?
<span id="L234" class="LineNr"> 234 </span>    result <span class="Special">&lt;-</span> add result,<span class="Constant"> 1</span>
<span id="L235" class="LineNr"> 235 </span>   <span class="muControl"> loop</span>
<span id="L236" class="LineNr"> 236 </span>  <span class="Delimiter">}</span>
<span id="L237" class="LineNr"> 237 </span>]
<span id="L238" class="LineNr"> 238 </span>
<span id="L239" class="LineNr"> 239 </span><span class="muScenario">scenario</span> editor-clears-last-line-on-backspace [
<span id="L240" class="LineNr"> 240 </span>  <span class="Constant">local-scope</span>
<span id="L241" class="LineNr"> 241 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L242" class="LineNr"> 242 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[ab</span>
<span id="L243" class="LineNr"> 243 </span><span class="Constant">cd]</span>
<span id="L244" class="LineNr"> 244 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L245" class="LineNr"> 245 </span>  assume-console [
<span id="L246" class="LineNr"> 246 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
<span id="L247" class="LineNr"> 247 </span>    press backspace
<span id="L248" class="LineNr"> 248 </span>  ]
<span id="L249" class="LineNr"> 249 </span>  run [
<span id="L250" class="LineNr"> 250 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L251" class="LineNr"> 251 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L252" class="LineNr"> 252 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L253" class="LineNr"> 253 </span>  ]
<span id="L254" class="LineNr"> 254 </span>  screen-should-contain [
<span id="L255" class="LineNr"> 255 </span>   <span class="Constant"> .          .</span>
<span id="L256" class="LineNr"> 256 </span>   <span class="Constant"> .abcd      .</span>
<span id="L257" class="LineNr"> 257 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L258" class="LineNr"> 258 </span>   <span class="Constant"> .          .</span>
<span id="L259" class="LineNr"> 259 </span>  ]
<span id="L260" class="LineNr"> 260 </span>  memory-should-contain [
<span id="L261" class="LineNr"> 261 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L262" class="LineNr"> 262 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L263" class="LineNr"> 263 </span>  ]
<span id="L264" class="LineNr"> 264 </span>]
<span id="L265" class="LineNr"> 265 </span>
<span id="L266" class="LineNr"> 266 </span><span class="muScenario">scenario</span> editor-joins-and-wraps-lines-on-backspace [
<span id="L267" class="LineNr"> 267 </span>  <span class="Constant">local-scope</span>
<span id="L268" class="LineNr"> 268 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L269" class="LineNr"> 269 </span>  <span class="Comment"># initialize editor with two long-ish but non-wrapping lines</span>
<span id="L270" class="LineNr"> 270 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc def</span>
<span id="L271" class="LineNr"> 271 </span><span class="Constant">ghi jkl]</span>
<span id="L272" class="LineNr"> 272 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L273" class="LineNr"> 273 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L274" class="LineNr"> 274 </span>  $clear-trace
<span id="L275" class="LineNr"> 275 </span>  <span class="Comment"># position the cursor at the start of the second and hit backspace</span>
<span id="L276" class="LineNr"> 276 </span>  assume-console [
<span id="L277" class="LineNr"> 277 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
<span id="L278" class="LineNr"> 278 </span>    press backspace
<span id="L279" class="LineNr"> 279 </span>  ]
<span id="L280" class="LineNr"> 280 </span>  run [
<span id="L281" class="LineNr"> 281 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L282" class="LineNr"> 282 </span>  ]
<span id="L283" class="LineNr"> 283 </span>  <span class="Comment"># resulting single line should wrap correctly</span>
<span id="L284" class="LineNr"> 284 </span>  screen-should-contain [
<span id="L285" class="LineNr"> 285 </span>   <span class="Constant"> .          .</span>
<span id="L286" class="LineNr"> 286 </span>   <span class="Constant"> .abc defgh↩.</span>
<span id="L287" class="LineNr"> 287 </span>   <span class="Constant"> .i jkl     .</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="L290" class="LineNr"> 290 </span>  ]
<span id="L291" class="LineNr"> 291 </span>]
<span id="L292" class="LineNr"> 292 </span>
<span id="L293" class="LineNr"> 293 </span><span class="muScenario">scenario</span> editor-wraps-long-lines-on-backspace [
<span id="L294" class="LineNr"> 294 </span>  <span class="Constant">local-scope</span>
<span id="L295" class="LineNr"> 295 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L296" class="LineNr"> 296 </span>  <span class="Comment"># initialize editor in part of the screen with a long line</span>
<span id="L297" class="LineNr"> 297 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abc def ghij]</span>, <span class="Constant">0/left</span>, <span class="Constant">8/right</span>
<span id="L298" class="LineNr"> 298 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L299" class="LineNr"> 299 </span>  <span class="Comment"># confirm that it wraps</span>
<span id="L300" class="LineNr"> 300 </span>  screen-should-contain [
<span id="L301" class="LineNr"> 301 </span>   <span class="Constant"> .          .</span>
<span id="L302" class="LineNr"> 302 </span>   <span class="Constant"> .abc def↩  .</span>
<span id="L303" class="LineNr"> 303 </span>   <span class="Constant"> . ghij     .</span>
<span id="L304" class="LineNr"> 304 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌  .</span>
<span id="L305" class="LineNr"> 305 </span>  ]
<span id="L306" class="LineNr"> 306 </span>  $clear-trace
<span id="L307" class="LineNr"> 307 </span>  <span class="Comment"># position the cursor somewhere in the middle of the top screen line and hit backspace</span>
<span id="L308" class="LineNr"> 308 </span>  assume-console [
<span id="L309" class="LineNr"> 309 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 4</span>
<span id="L310" class="LineNr"> 310 </span>    press backspace
<span id="L311" class="LineNr"> 311 </span>  ]
<span id="L312" class="LineNr"> 312 </span>  run [
<span id="L313" class="LineNr"> 313 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L314" class="LineNr"> 314 </span>  ]
<span id="L315" class="LineNr"> 315 </span>  <span class="Comment"># resulting single line should wrap correctly and not overflow its bounds</span>
<span id="L316" class="LineNr"> 316 </span>  screen-should-contain [
<span id="L317" class="LineNr"> 317 </span>   <span class="Constant"> .          .</span>
<span id="L318" class="LineNr"> 318 </span>   <span class="Constant"> .abcdef ↩  .</span>
<span id="L319" class="LineNr"> 319 </span>   <span class="Constant"> .ghij      .</span>
<span id="L320" class="LineNr"> 320 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌  .</span>
<span id="L321" class="LineNr"> 321 </span>   <span class="Constant"> .          .</span>
<span id="L322" class="LineNr"> 322 </span>  ]
<span id="L323" class="LineNr"> 323 </span>]
<span id="L324" class="LineNr"> 324 </span>
<span id="L325" class="LineNr"> 325 </span><span class="Comment"># delete - delete character at cursor</span>
<span id="L326" class="LineNr"> 326 </span>
<span id="L327" class="LineNr"> 327 </span><span class="muScenario">scenario</span> editor-handles-delete-key [
<span id="L328" class="LineNr"> 328 </span>  <span class="Constant">local-scope</span>
<span id="L329" class="LineNr"> 329 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L330" class="LineNr"> 330 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abc]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L331" class="LineNr"> 331 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L332" class="LineNr"> 332 </span>  $clear-trace
<span id="L333" class="LineNr"> 333 </span>  assume-console [
<span id="L334" class="LineNr"> 334 </span>    press delete
<span id="L335" class="LineNr"> 335 </span>  ]
<span id="L336" class="LineNr"> 336 </span>  run [
<span id="L337" class="LineNr"> 337 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L338" class="LineNr"> 338 </span>  ]
<span id="L339" class="LineNr"> 339 </span>  screen-should-contain [
<span id="L340" class="LineNr"> 340 </span>   <span class="Constant"> .          .</span>
<span id="L341" class="LineNr"> 341 </span>   <span class="Constant"> .bc        .</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 id="L345" class="LineNr"> 345 </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="L346" class="LineNr"> 346 </span>  $clear-trace
<span id="L347" class="LineNr"> 347 </span>  assume-console [
<span id="L348" class="LineNr"> 348 </span>    press delete
<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#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L352" class="LineNr"> 352 </span>  ]
<span id="L353" class="LineNr"> 353 </span>  screen-should-contain [
<span id="L354" class="LineNr"> 354 </span>   <span class="Constant"> .          .</span>
<span id="L355" class="LineNr"> 355 </span>   <span class="Constant"> .c         .</span>
<span id="L356" class="LineNr"> 356 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L357" class="LineNr"> 357 </span>   <span class="Constant"> .          .</span>
<span id="L358" class="LineNr"> 358 </span>  ]
<span id="L359" class="LineNr"> 359 </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="L360" class="LineNr"> 360 </span>]
<span id="L361" class="LineNr"> 361 </span>
<span id="L362" class="LineNr"> 362 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L199'>&lt;handle-special-key&gt;</a></span> [
<span id="L363" class="LineNr"> 363 </span>  <span class="Delimiter">{</span>
<span id="L364" class="LineNr"> 364 </span>    delete-next-character?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65522/delete</span>
<span id="L365" class="LineNr"> 365 </span>    <span class="muControl">break-unless</span> delete-next-character?
<span id="L366" class="LineNr"> 366 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L366'>&lt;begin-delete-character&gt;</a></span>
<span id="L367" class="LineNr"> 367 </span>    go-render?:bool, deleted-cell:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L373'>delete-at-cursor</a> editor, <a href='../081print.mu.html#L16'>screen</a>
<span id="L368" class="LineNr"> 368 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L368'>&lt;end-delete-character&gt;</a></span>
<span id="L369" class="LineNr"> 369 </span>   <span class="muControl"> return</span>
<span id="L370" class="LineNr"> 370 </span>  <span class="Delimiter">}</span>
<span id="L371" class="LineNr"> 371 </span>]
<span id="L372" class="LineNr"> 372 </span>
<span id="L373" class="LineNr"> 373 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L373'>delete-at-cursor</a> editor:&amp;:editor, <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a><span class="muRecipe"> -&gt; </span>go-render?:bool, deleted-cell:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char, editor:&amp;:editor, <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a> [
<span id="L374" class="LineNr"> 374 </span>  <span class="Constant">local-scope</span>
<span id="L375" class="LineNr"> 375 </span>  <span class="Constant">load-inputs</span>
<span id="L376" class="LineNr"> 376 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L377" class="LineNr"> 377 </span>  data:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
<span id="L378" class="LineNr"> 378 </span>  deleted-cell:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-cursor
<span id="L379" class="LineNr"> 379 </span>  <span class="muControl">return-unless</span> deleted-cell,<span class="Constant"> false/don't-render</span>
<span id="L380" class="LineNr"> 380 </span>  currc:char <span class="Special">&lt;-</span> get *deleted-cell, <span class="Constant">value:offset</span>
<span id="L381" class="LineNr"> 381 </span>  data <span class="Special">&lt;-</span> remove deleted-cell, data
<span id="L382" class="LineNr"> 382 </span>  deleted-newline?:bool <span class="Special">&lt;-</span> equal currc, <span class="Constant">10/newline</span>
<span id="L383" class="LineNr"> 383 </span>  <span class="muControl">return-if</span> deleted-newline?,<span class="Constant"> true/go-render</span>
<span id="L384" class="LineNr"> 384 </span>  <span class="Comment"># wasn't a newline? render rest of line</span>
<span id="L385" class="LineNr"> 385 </span>  curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-cursor  <span class="Comment"># refresh after remove above</span>
<span id="L386" class="LineNr"> 386 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L387" class="LineNr"> 387 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L388" class="LineNr"> 388 </span>  <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> move-cursor <a href='../081print.mu.html#L16'>screen</a>, cursor-row, cursor-column
<span id="L389" class="LineNr"> 389 </span>  curr-column:num <span class="Special">&lt;-</span> copy cursor-column
<span id="L390" class="LineNr"> 390 </span>  <a href='../081print.mu.html#L768'>screen-width</a>:num <span class="Special">&lt;-</span> <a href='../081print.mu.html#L768'>screen-width</a> <a href='../081print.mu.html#L16'>screen</a>
<span id="L391" class="LineNr"> 391 </span>  <span class="Delimiter">{</span>
<span id="L392" class="LineNr"> 392 </span>    <span class="Comment"># hit right margin? give up and let caller render</span>
<span id="L393" class="LineNr"> 393 </span>    at-right?:bool <span class="Special">&lt;-</span> greater-or-equal curr-column, <a href='../081print.mu.html#L768'>screen-width</a>
<span id="L394" class="LineNr"> 394 </span>    <span class="muControl">return-if</span> at-right?,<span class="Constant"> true/go-render</span>
<span id="L395" class="LineNr"> 395 </span>    <span class="muControl">break-unless</span> curr
<span id="L396" class="LineNr"> 396 </span>    currc:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
<span id="L397" class="LineNr"> 397 </span>    at-newline?:bool <span class="Special">&lt;-</span> equal currc, <span class="Constant">10/newline</span>
<span id="L398" class="LineNr"> 398 </span>    <span class="muControl">break-if</span> at-newline?
<span id="L399" class="LineNr"> 399 </span>    <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> print <a href='../081print.mu.html#L16'>screen</a>, currc
<span id="L400" class="LineNr"> 400 </span>    curr-column <span class="Special">&lt;-</span> add curr-column,<span class="Constant"> 1</span>
<span id="L401" class="LineNr"> 401 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> curr
<span id="L402" class="LineNr"> 402 </span>   <span class="muControl"> loop</span>
<span id="L403" class="LineNr"> 403 </span>  <span class="Delimiter">}</span>
<span id="L404" class="LineNr"> 404 </span>  <span class="Comment"># we're guaranteed not to be at the right margin</span>
<span id="L405" class="LineNr"> 405 </span>  space:char <span class="Special">&lt;-</span> copy <span class="Constant">32/space</span>
<span id="L406" class="LineNr"> 406 </span>  <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> print <a href='../081print.mu.html#L16'>screen</a>, space
<span id="L407" class="LineNr"> 407 </span>  go-render? <span class="Special">&lt;-</span> copy<span class="Constant"> false</span>
<span id="L408" class="LineNr"> 408 </span>]
<span id="L409" class="LineNr"> 409 </span>
<span id="L410" class="LineNr"> 410 </span><span class="Comment"># right arrow</span>
<span id="L411" class="LineNr"> 411 </span>
<span id="L412" class="LineNr"> 412 </span><span class="muScenario">scenario</span> editor-moves-cursor-right-with-key [
<span id="L413" class="LineNr"> 413 </span>  <span class="Constant">local-scope</span>
<span id="L414" class="LineNr"> 414 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L415" class="LineNr"> 415 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abc]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L416" class="LineNr"> 416 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L417" class="LineNr"> 417 </span>  $clear-trace
<span id="L418" class="LineNr"> 418 </span>  assume-console [
<span id="L419" class="LineNr"> 419 </span>    press right-arrow
<span id="L420" class="LineNr"> 420 </span>    type <span class="Constant">[0]</span>
<span id="L421" class="LineNr"> 421 </span>  ]
<span id="L422" class="LineNr"> 422 </span>  run [
<span id="L423" class="LineNr"> 423 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L424" class="LineNr"> 424 </span>  ]
<span id="L425" class="LineNr"> 425 </span>  screen-should-contain [
<span id="L426" class="LineNr"> 426 </span>   <span class="Constant"> .          .</span>
<span id="L427" class="LineNr"> 427 </span>   <span class="Constant"> .a0bc      .</span>
<span id="L428" class="LineNr"> 428 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L429" class="LineNr"> 429 </span>   <span class="Constant"> .          .</span>
<span id="L430" class="LineNr"> 430 </span>  ]
<span id="L431" class="LineNr"> 431 </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="L432" class="LineNr"> 432 </span>]
<span id="L433" class="LineNr"> 433 </span>
<span id="L434" class="LineNr"> 434 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L199'>&lt;handle-special-key&gt;</a></span> [
<span id="L435" class="LineNr"> 435 </span>  <span class="Delimiter">{</span>
<span id="L436" class="LineNr"> 436 </span>    move-to-next-character?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65514/right-arrow</span>
<span id="L437" class="LineNr"> 437 </span>    <span class="muControl">break-unless</span> move-to-next-character?
<span id="L438" class="LineNr"> 438 </span>    <span class="Comment"># if not at end of text</span>
<span id="L439" class="LineNr"> 439 </span>    next-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-cursor
<span id="L440" class="LineNr"> 440 </span>    <span class="muControl">break-unless</span> next-cursor
<span id="L441" class="LineNr"> 441 </span>    <span class="Comment"># scan to next character</span>
<span id="L442" class="LineNr"> 442 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L443" class="LineNr"> 443 </span>    before-cursor <span class="Special">&lt;-</span> copy next-cursor
<span id="L444" class="LineNr"> 444 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L445" class="LineNr"> 445 </span>    go-render?:bool <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L453'>move-cursor-coordinates-right</a> editor, <a href='../081print.mu.html#L782'>screen-height</a>
<span id="L446" class="LineNr"> 446 </span>    <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> move-cursor <a href='../081print.mu.html#L16'>screen</a>, cursor-row, cursor-column
<span id="L447" class="LineNr"> 447 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">2/right-arrow</span>
<span id="L448" class="LineNr"> 448 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L449" class="LineNr"> 449 </span>   <span class="muControl"> return</span>
<span id="L450" class="LineNr"> 450 </span>  <span class="Delimiter">}</span>
<span id="L451" class="LineNr"> 451 </span>]
<span id="L452" class="LineNr"> 452 </span>
<span id="L453" class="LineNr"> 453 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L453'>move-cursor-coordinates-right</a> editor:&amp;:editor, <a href='../081print.mu.html#L782'>screen-height</a>:num<span class="muRecipe"> -&gt; </span>go-render?:bool, editor:&amp;:editor [
<span id="L454" class="LineNr"> 454 </span>  <span class="Constant">local-scope</span>
<span id="L455" class="LineNr"> 455 </span>  <span class="Constant">load-inputs</span>
<span id="L456" class="LineNr"> 456 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor <span class="Constant">before-cursor:offset</span>
<span id="L457" class="LineNr"> 457 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L458" class="LineNr"> 458 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L459" class="LineNr"> 459 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L460" class="LineNr"> 460 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L461" class="LineNr"> 461 </span>  <span class="Comment"># if crossed a newline, move cursor to start of next row</span>
<span id="L462" class="LineNr"> 462 </span>  <span class="Delimiter">{</span>
<span id="L463" class="LineNr"> 463 </span>    old-cursor-character:char <span class="Special">&lt;-</span> get *before-cursor, <span class="Constant">value:offset</span>
<span id="L464" class="LineNr"> 464 </span>    was-at-newline?:bool <span class="Special">&lt;-</span> equal old-cursor-character, <span class="Constant">10/newline</span>
<span id="L465" class="LineNr"> 465 </span>    <span class="muControl">break-unless</span> was-at-newline?
<span id="L466" class="LineNr"> 466 </span>    cursor-row <span class="Special">&lt;-</span> add cursor-row,<span class="Constant"> 1</span>
<span id="L467" class="LineNr"> 467 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
<span id="L468" class="LineNr"> 468 </span>    cursor-column <span class="Special">&lt;-</span> copy left
<span id="L469" class="LineNr"> 469 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L470" class="LineNr"> 470 </span>    below-screen?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-row, <a href='../081print.mu.html#L782'>screen-height</a>  <span class="Comment"># must be equal</span>
<span id="L471" class="LineNr"> 471 </span>    <span class="muControl">return-unless</span> below-screen?,<span class="Constant"> false/don't-render</span>
<span id="L472" class="LineNr"> 472 </span><span class="Constant">    &lt;scroll-down&gt;</span>
<span id="L473" class="LineNr"> 473 </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="L474" class="LineNr"> 474 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
<span id="L475" class="LineNr"> 475 </span>   <span class="muControl"> return</span><span class="Constant"> true/go-render</span>
<span id="L476" class="LineNr"> 476 </span>  <span class="Delimiter">}</span>
<span id="L477" class="LineNr"> 477 </span>  <span class="Comment"># if the line wraps, move cursor to start of next row</span>
<span id="L478" class="LineNr"> 478 </span>  <span class="Delimiter">{</span>
<span id="L479" class="LineNr"> 479 </span>    <span class="Comment"># if we're at the column just before the wrap indicator</span>
<span id="L480" class="LineNr"> 480 </span>    wrap-column:num <span class="Special">&lt;-</span> subtract right,<span class="Constant"> 1</span>
<span id="L481" class="LineNr"> 481 </span>    at-wrap?:bool <span class="Special">&lt;-</span> equal cursor-column, wrap-column
<span id="L482" class="LineNr"> 482 </span>    <span class="muControl">break-unless</span> at-wrap?
<span id="L483" class="LineNr"> 483 </span>    <span class="Comment"># and if next character isn't newline</span>
<span id="L484" class="LineNr"> 484 </span>    <a href='../065duplex_list.mu.html#L31'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-cursor
<span id="L485" class="LineNr"> 485 </span>    <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L31'>next</a>
<span id="L486" class="LineNr"> 486 </span>    next-character:char <span class="Special">&lt;-</span> get *next, <span class="Constant">value:offset</span>
<span id="L487" class="LineNr"> 487 </span>    newline?:bool <span class="Special">&lt;-</span> equal next-character, <span class="Constant">10/newline</span>
<span id="L488" class="LineNr"> 488 </span>    <span class="muControl">break-if</span> newline?
<span id="L489" class="LineNr"> 489 </span>    cursor-row <span class="Special">&lt;-</span> add cursor-row,<span class="Constant"> 1</span>
<span id="L490" class="LineNr"> 490 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
<span id="L491" class="LineNr"> 491 </span>    cursor-column <span class="Special">&lt;-</span> copy left
<span id="L492" class="LineNr"> 492 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L493" class="LineNr"> 493 </span>    below-screen?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-row, <a href='../081print.mu.html#L782'>screen-height</a>  <span class="Comment"># must be equal</span>
<span id="L494" class="LineNr"> 494 </span>    <span class="muControl">return-unless</span> below-screen?,<span class="Constant"> false/no-more-render</span>
<span id="L495" class="LineNr"> 495 </span><span class="Constant">    &lt;scroll-down&gt;</span>
<span id="L496" class="LineNr"> 496 </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="L497" class="LineNr"> 497 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
<span id="L498" class="LineNr"> 498 </span>   <span class="muControl"> return</span><span class="Constant"> true/go-render</span>
<span id="L499" class="LineNr"> 499 </span>  <span class="Delimiter">}</span>
<span id="L500" class="LineNr"> 500 </span>  <span class="Comment"># otherwise move cursor one character right</span>
<span id="L501" class="LineNr"> 501 </span>  cursor-column <span class="Special">&lt;-</span> add cursor-column,<span class="Constant"> 1</span>
<span id="L502" class="LineNr"> 502 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L503" class="LineNr"> 503 </span>  go-render? <span class="Special">&lt;-</span> copy<span class="Constant"> false</span>
<span id="L504" class="LineNr"> 504 </span>]
<span id="L505" class="LineNr"> 505 </span>
<span id="L506" class="LineNr"> 506 </span><span class="muScenario">scenario</span> editor-moves-cursor-to-next-line-with-right-arrow [
<span id="L507" class="LineNr"> 507 </span>  <span class="Constant">local-scope</span>
<span id="L508" class="LineNr"> 508 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L509" class="LineNr"> 509 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L510" class="LineNr"> 510 </span><span class="Constant">d]</span>
<span id="L511" class="LineNr"> 511 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L512" class="LineNr"> 512 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L513" class="LineNr"> 513 </span>  $clear-trace
<span id="L514" class="LineNr"> 514 </span>  <span class="Comment"># type right-arrow a few times to get to start of second line</span>
<span id="L515" class="LineNr"> 515 </span>  assume-console [
<span id="L516" class="LineNr"> 516 </span>    press right-arrow
<span id="L517" class="LineNr"> 517 </span>    press right-arrow
<span id="L518" class="LineNr"> 518 </span>    press right-arrow
<span id="L519" class="LineNr"> 519 </span>    press right-arrow  <span class="Comment"># next line</span>
<span id="L520" class="LineNr"> 520 </span>  ]
<span id="L521" class="LineNr"> 521 </span>  run [
<span id="L522" class="LineNr"> 522 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L523" class="LineNr"> 523 </span>  ]
<span id="L524" class="LineNr"> 524 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L525" class="LineNr"> 525 </span>  <span class="Comment"># type something and ensure it goes where it should</span>
<span id="L526" class="LineNr"> 526 </span>  assume-console [
<span id="L527" class="LineNr"> 527 </span>    type <span class="Constant">[0]</span>
<span id="L528" class="LineNr"> 528 </span>  ]
<span id="L529" class="LineNr"> 529 </span>  run [
<span id="L530" class="LineNr"> 530 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L531" class="LineNr"> 531 </span>  ]
<span id="L532" class="LineNr"> 532 </span>  screen-should-contain [
<span id="L533" class="LineNr"> 533 </span>   <span class="Constant"> .          .</span>
<span id="L534" class="LineNr"> 534 </span>   <span class="Constant"> .abc       .</span>
<span id="L535" class="LineNr"> 535 </span>   <span class="Constant"> .0d        .</span>
<span id="L536" class="LineNr"> 536 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L537" class="LineNr"> 537 </span>   <span class="Constant"> .          .</span>
<span id="L538" class="LineNr"> 538 </span>  ]
<span id="L539" class="LineNr"> 539 </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="L540" class="LineNr"> 540 </span>]
<span id="L541" class="LineNr"> 541 </span>
<span id="L542" class="LineNr"> 542 </span><span class="muScenario">scenario</span> editor-moves-cursor-to-next-line-with-right-arrow-2 [
<span id="L543" class="LineNr"> 543 </span>  <span class="Constant">local-scope</span>
<span id="L544" class="LineNr"> 544 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L545" class="LineNr"> 545 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L546" class="LineNr"> 546 </span><span class="Constant">d]</span>
<span id="L547" class="LineNr"> 547 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">1/left</span>, <span class="Constant">10/right</span>
<span id="L548" class="LineNr"> 548 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L549" class="LineNr"> 549 </span>  assume-console [
<span id="L550" class="LineNr"> 550 </span>    press right-arrow
<span id="L551" class="LineNr"> 551 </span>    press right-arrow
<span id="L552" class="LineNr"> 552 </span>    press right-arrow
<span id="L553" class="LineNr"> 553 </span>    press right-arrow  <span class="Comment"># next line</span>
<span id="L554" class="LineNr"> 554 </span>    type <span class="Constant">[0]</span>
<span id="L555" class="LineNr"> 555 </span>  ]
<span id="L556" class="LineNr"> 556 </span>  run [
<span id="L557" class="LineNr"> 557 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<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"> . abc      .</span>
<span id="L562" class="LineNr"> 562 </span>   <span class="Constant"> . 0d       .</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="L565" class="LineNr"> 565 </span>  ]
<span id="L566" class="LineNr"> 566 </span>]
<span id="L567" class="LineNr"> 567 </span>
<span id="L568" class="LineNr"> 568 </span><span class="muScenario">scenario</span> editor-moves-cursor-to-next-wrapped-line-with-right-arrow [
<span id="L569" class="LineNr"> 569 </span>  <span class="Constant">local-scope</span>
<span id="L570" class="LineNr"> 570 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L571" class="LineNr"> 571 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abcdef]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L572" class="LineNr"> 572 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L573" class="LineNr"> 573 </span>  $clear-trace
<span id="L574" class="LineNr"> 574 </span>  assume-console [
<span id="L575" class="LineNr"> 575 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
<span id="L576" class="LineNr"> 576 </span>    press right-arrow
<span id="L577" class="LineNr"> 577 </span>  ]
<span id="L578" class="LineNr"> 578 </span>  run [
<span id="L579" class="LineNr"> 579 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L580" class="LineNr"> 580 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L581" class="LineNr"> 581 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</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"> .abcd↩     .</span>
<span id="L586" class="LineNr"> 586 </span>   <span class="Constant"> .ef        .</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 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="L593" class="LineNr"> 593 </span>  ]
<span id="L594" class="LineNr"> 594 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L595" class="LineNr"> 595 </span>]
<span id="L596" class="LineNr"> 596 </span>
<span id="L597" class="LineNr"> 597 </span><span class="muScenario">scenario</span> editor-moves-cursor-to-next-wrapped-line-with-right-arrow-2 [
<span id="L598" class="LineNr"> 598 </span>  <span class="Constant">local-scope</span>
<span id="L599" class="LineNr"> 599 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L600" class="LineNr"> 600 </span>  <span class="Comment"># line just barely wrapping</span>
<span id="L601" class="LineNr"> 601 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abcde]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L602" class="LineNr"> 602 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L603" class="LineNr"> 603 </span>  $clear-trace
<span id="L604" class="LineNr"> 604 </span>  <span class="Comment"># position cursor at last character before wrap and hit right-arrow</span>
<span id="L605" class="LineNr"> 605 </span>  assume-console [
<span id="L606" class="LineNr"> 606 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
<span id="L607" class="LineNr"> 607 </span>    press right-arrow
<span id="L608" class="LineNr"> 608 </span>  ]
<span id="L609" class="LineNr"> 609 </span>  run [
<span id="L610" class="LineNr"> 610 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L611" class="LineNr"> 611 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L612" class="LineNr"> 612 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L613" class="LineNr"> 613 </span>  ]
<span id="L614" class="LineNr"> 614 </span>  memory-should-contain [
<span id="L615" class="LineNr"> 615 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L616" class="LineNr"> 616 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L617" class="LineNr"> 617 </span>  ]
<span id="L618" class="LineNr"> 618 </span>  <span class="Comment"># now hit right arrow again</span>
<span id="L619" class="LineNr"> 619 </span>  assume-console [
<span id="L620" class="LineNr"> 620 </span>    press right-arrow
<span id="L621" class="LineNr"> 621 </span>  ]
<span id="L622" class="LineNr"> 622 </span>  run [
<span id="L623" class="LineNr"> 623 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L624" class="LineNr"> 624 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L625" class="LineNr"> 625 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L626" class="LineNr"> 626 </span>  ]
<span id="L627" class="LineNr"> 627 </span>  memory-should-contain [
<span id="L628" class="LineNr"> 628 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L629" class="LineNr"> 629 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L630" class="LineNr"> 630 </span>  ]
<span id="L631" class="LineNr"> 631 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L632" class="LineNr"> 632 </span>]
<span id="L633" class="LineNr"> 633 </span>
<span id="L634" class="LineNr"> 634 </span><span class="muScenario">scenario</span> editor-moves-cursor-to-next-wrapped-line-with-right-arrow-3 [
<span id="L635" class="LineNr"> 635 </span>  <span class="Constant">local-scope</span>
<span id="L636" class="LineNr"> 636 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L637" class="LineNr"> 637 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abcdef]</span>, <span class="Constant">1/left</span>, <span class="Constant">6/right</span>
<span id="L638" class="LineNr"> 638 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L639" class="LineNr"> 639 </span>  $clear-trace
<span id="L640" class="LineNr"> 640 </span>  assume-console [
<span id="L641" class="LineNr"> 641 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 4</span>
<span id="L642" class="LineNr"> 642 </span>    press right-arrow
<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#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L646" class="LineNr"> 646 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L647" class="LineNr"> 647 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L648" class="LineNr"> 648 </span>  ]
<span id="L649" class="LineNr"> 649 </span>  screen-should-contain [
<span id="L650" class="LineNr"> 650 </span>   <span class="Constant"> .          .</span>
<span id="L651" class="LineNr"> 651 </span>   <span class="Constant"> . abcd↩    .</span>
<span id="L652" class="LineNr"> 652 </span>   <span class="Constant"> . ef       .</span>
<span id="L653" class="LineNr"> 653 </span>   <span class="Constant"> . ╌╌╌╌╌    .</span>
<span id="L654" class="LineNr"> 654 </span>   <span class="Constant"> .          .</span>
<span id="L655" class="LineNr"> 655 </span>  ]
<span id="L656" class="LineNr"> 656 </span>  memory-should-contain [
<span id="L657" class="LineNr"> 657 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L658" class="LineNr"> 658 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L659" class="LineNr"> 659 </span>  ]
<span id="L660" class="LineNr"> 660 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L661" class="LineNr"> 661 </span>]
<span id="L662" class="LineNr"> 662 </span>
<span id="L663" class="LineNr"> 663 </span><span class="muScenario">scenario</span> editor-moves-cursor-to-next-line-with-right-arrow-at-end-of-line [
<span id="L664" class="LineNr"> 664 </span>  <span class="Constant">local-scope</span>
<span id="L665" class="LineNr"> 665 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L666" class="LineNr"> 666 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L667" class="LineNr"> 667 </span><span class="Constant">d]</span>
<span id="L668" class="LineNr"> 668 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L669" class="LineNr"> 669 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L670" class="LineNr"> 670 </span>  $clear-trace
<span id="L671" class="LineNr"> 671 </span>  <span class="Comment"># move to end of line, press right-arrow, type a character</span>
<span id="L672" class="LineNr"> 672 </span>  assume-console [
<span id="L673" class="LineNr"> 673 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
<span id="L674" class="LineNr"> 674 </span>    press right-arrow
<span id="L675" class="LineNr"> 675 </span>    type <span class="Constant">[0]</span>
<span id="L676" class="LineNr"> 676 </span>  ]
<span id="L677" class="LineNr"> 677 </span>  run [
<span id="L678" class="LineNr"> 678 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L679" class="LineNr"> 679 </span>  ]
<span id="L680" class="LineNr"> 680 </span>  <span class="Comment"># new character should be in next line</span>
<span id="L681" class="LineNr"> 681 </span>  screen-should-contain [
<span id="L682" class="LineNr"> 682 </span>   <span class="Constant"> .          .</span>
<span id="L683" class="LineNr"> 683 </span>   <span class="Constant"> .abc       .</span>
<span id="L684" class="LineNr"> 684 </span>   <span class="Constant"> .0d        .</span>
<span id="L685" class="LineNr"> 685 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L686" class="LineNr"> 686 </span>   <span class="Constant"> .          .</span>
<span id="L687" class="LineNr"> 687 </span>  ]
<span id="L688" class="LineNr"> 688 </span>  check-trace-count-for-label<span class="Constant"> 2</span>, <span class="Constant">[print-character]</span>
<span id="L689" class="LineNr"> 689 </span>]
<span id="L690" class="LineNr"> 690 </span>
<span id="L691" class="LineNr"> 691 </span><span class="Comment"># todo: ctrl-right: next word-end</span>
<span id="L692" class="LineNr"> 692 </span>
<span id="L693" class="LineNr"> 693 </span><span class="Comment"># left arrow</span>
<span id="L694" class="LineNr"> 694 </span>
<span id="L695" class="LineNr"> 695 </span><span class="muScenario">scenario</span> editor-moves-cursor-left-with-key [
<span id="L696" class="LineNr"> 696 </span>  <span class="Constant">local-scope</span>
<span id="L697" class="LineNr"> 697 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L698" class="LineNr"> 698 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abc]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L699" class="LineNr"> 699 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L700" class="LineNr"> 700 </span>  $clear-trace
<span id="L701" class="LineNr"> 701 </span>  assume-console [
<span id="L702" class="LineNr"> 702 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 2</span>
<span id="L703" class="LineNr"> 703 </span>    press left-arrow
<span id="L704" class="LineNr"> 704 </span>    type <span class="Constant">[0]</span>
<span id="L705" class="LineNr"> 705 </span>  ]
<span id="L706" class="LineNr"> 706 </span>  run [
<span id="L707" class="LineNr"> 707 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L708" class="LineNr"> 708 </span>  ]
<span id="L709" class="LineNr"> 709 </span>  screen-should-contain [
<span id="L710" class="LineNr"> 710 </span>   <span class="Constant"> .          .</span>
<span id="L711" class="LineNr"> 711 </span>   <span class="Constant"> .a0bc      .</span>
<span id="L712" class="LineNr"> 712 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L713" class="LineNr"> 713 </span>   <span class="Constant"> .          .</span>
<span id="L714" class="LineNr"> 714 </span>  ]
<span id="L715" class="LineNr"> 715 </span>  check-trace-count-for-label<span class="Constant"> 3</span>, <span class="Constant">[print-character]</span>
<span id="L716" class="LineNr"> 716 </span>]
<span id="L717" class="LineNr"> 717 </span>
<span id="L718" class="LineNr"> 718 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L199'>&lt;handle-special-key&gt;</a></span> [
<span id="L719" class="LineNr"> 719 </span>  <span class="Delimiter">{</span>
<span id="L720" class="LineNr"> 720 </span>    move-to-previous-character?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65515/left-arrow</span>
<span id="L721" class="LineNr"> 721 </span>    <span class="muControl">break-unless</span> move-to-previous-character?
<span id="L722" class="LineNr"> 722 </span>    trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[left arrow]</span>
<span id="L723" class="LineNr"> 723 </span>    <span class="Comment"># if not at start of text (before-cursor at § sentinel)</span>
<span id="L724" class="LineNr"> 724 </span>    <a href='../065duplex_list.mu.html#L38'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L38'>prev</a> before-cursor
<span id="L725" class="LineNr"> 725 </span>    <span class="muControl">return-unless</span> <a href='../065duplex_list.mu.html#L38'>prev</a>,<span class="Constant"> false/don't-render</span>
<span id="L726" class="LineNr"> 726 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L727" class="LineNr"> 727 </span>    go-render? <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L156'>move-cursor-coordinates-left</a> editor
<span id="L728" class="LineNr"> 728 </span>    before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L38'>prev</a>
<span id="L729" class="LineNr"> 729 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L730" class="LineNr"> 730 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">1/left-arrow</span>
<span id="L731" class="LineNr"> 731 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L732" class="LineNr"> 732 </span>   <span class="muControl"> return</span>
<span id="L733" class="LineNr"> 733 </span>  <span class="Delimiter">}</span>
<span id="L734" class="LineNr"> 734 </span>]
<span id="L735" class="LineNr"> 735 </span>
<span id="L736" class="LineNr"> 736 </span><span class="muScenario">scenario</span> editor-moves-cursor-to-previous-line-with-left-arrow-at-start-of-line [
<span id="L737" class="LineNr"> 737 </span>  <span class="Constant">local-scope</span>
<span id="L738" class="LineNr"> 738 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L739" class="LineNr"> 739 </span>  <span class="Comment"># initialize editor with two lines</span>
<span id="L740" class="LineNr"> 740 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L741" class="LineNr"> 741 </span><span class="Constant">d]</span>
<span id="L742" class="LineNr"> 742 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L743" class="LineNr"> 743 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L744" class="LineNr"> 744 </span>  $clear-trace
<span id="L745" class="LineNr"> 745 </span>  <span class="Comment"># position cursor at start of second line (so there's no previous newline)</span>
<span id="L746" class="LineNr"> 746 </span>  assume-console [
<span id="L747" class="LineNr"> 747 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
<span id="L748" class="LineNr"> 748 </span>    press left-arrow
<span id="L749" class="LineNr"> 749 </span>  ]
<span id="L750" class="LineNr"> 750 </span>  run [
<span id="L751" class="LineNr"> 751 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L752" class="LineNr"> 752 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L753" class="LineNr"> 753 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L754" class="LineNr"> 754 </span>  ]
<span id="L755" class="LineNr"> 755 </span>  memory-should-contain [
<span id="L756" class="LineNr"> 756 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L757" class="LineNr"> 757 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L758" class="LineNr"> 758 </span>  ]
<span id="L759" class="LineNr"> 759 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L760" class="LineNr"> 760 </span>]
<span id="L761" class="LineNr"> 761 </span>
<span id="L762" class="LineNr"> 762 </span><span class="muScenario">scenario</span> editor-moves-cursor-to-previous-line-with-left-arrow-at-start-of-line-2 [
<span id="L763" class="LineNr"> 763 </span>  <span class="Constant">local-scope</span>
<span id="L764" class="LineNr"> 764 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L765" class="LineNr"> 765 </span>  <span class="Comment"># initialize editor with three lines</span>
<span id="L766" class="LineNr"> 766 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L767" class="LineNr"> 767 </span><span class="Constant">def</span>
<span id="L768" class="LineNr"> 768 </span><span class="Constant">g]</span>
<span id="L769" class="LineNr"> 769 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s:text, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L770" class="LineNr"> 770 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L771" class="LineNr"> 771 </span>  $clear-trace
<span id="L772" class="LineNr"> 772 </span>  <span class="Comment"># position cursor further down (so there's a newline before the character at</span>
<span id="L773" class="LineNr"> 773 </span>  <span class="Comment"># the cursor)</span>
<span id="L774" class="LineNr"> 774 </span>  assume-console [
<span id="L775" class="LineNr"> 775 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
<span id="L776" class="LineNr"> 776 </span>    press left-arrow
<span id="L777" class="LineNr"> 777 </span>    type <span class="Constant">[0]</span>
<span id="L778" class="LineNr"> 778 </span>  ]
<span id="L779" class="LineNr"> 779 </span>  run [
<span id="L780" class="LineNr"> 780 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L781" class="LineNr"> 781 </span>  ]
<span id="L782" class="LineNr"> 782 </span>  screen-should-contain [
<span id="L783" class="LineNr"> 783 </span>   <span class="Constant"> .          .</span>
<span id="L784" class="LineNr"> 784 </span>   <span class="Constant"> .abc       .</span>
<span id="L785" class="LineNr"> 785 </span>   <span class="Constant"> .def0      .</span>
<span id="L786" class="LineNr"> 786 </span>   <span class="Constant"> .g         .</span>
<span id="L787" class="LineNr"> 787 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L788" class="LineNr"> 788 </span>  ]
<span id="L789" class="LineNr"> 789 </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="L790" class="LineNr"> 790 </span>]
<span id="L791" class="LineNr"> 791 </span>
<span id="L792" class="LineNr"> 792 </span><span class="muScenario">scenario</span> editor-moves-cursor-to-previous-line-with-left-arrow-at-start-of-line-3 [
<span id="L793" class="LineNr"> 793 </span>  <span class="Constant">local-scope</span>
<span id="L794" class="LineNr"> 794 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L795" class="LineNr"> 795 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L796" class="LineNr"> 796 </span><span class="Constant">def</span>
<span id="L797" class="LineNr"> 797 </span><span class="Constant">g]</span>
<span id="L798" class="LineNr"> 798 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L799" class="LineNr"> 799 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L800" class="LineNr"> 800 </span>  $clear-trace
<span id="L801" class="LineNr"> 801 </span>  <span class="Comment"># position cursor at start of text, press left-arrow, then type a character</span>
<span id="L802" class="LineNr"> 802 </span>  assume-console [
<span id="L803" class="LineNr"> 803 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 0</span>
<span id="L804" class="LineNr"> 804 </span>    press left-arrow
<span id="L805" class="LineNr"> 805 </span>    type <span class="Constant">[0]</span>
<span id="L806" class="LineNr"> 806 </span>  ]
<span id="L807" class="LineNr"> 807 </span>  run [
<span id="L808" class="LineNr"> 808 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L809" class="LineNr"> 809 </span>  ]
<span id="L810" class="LineNr"> 810 </span>  <span class="Comment"># left-arrow should have had no effect</span>
<span id="L811" class="LineNr"> 811 </span>  screen-should-contain [
<span id="L812" class="LineNr"> 812 </span>   <span class="Constant"> .          .</span>
<span id="L813" class="LineNr"> 813 </span>   <span class="Constant"> .0abc      .</span>
<span id="L814" class="LineNr"> 814 </span>   <span class="Constant"> .def       .</span>
<span id="L815" class="LineNr"> 815 </span>   <span class="Constant"> .g         .</span>
<span id="L816" class="LineNr"> 816 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L817" class="LineNr"> 817 </span>  ]
<span id="L818" class="LineNr"> 818 </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="L819" class="LineNr"> 819 </span>]
<span id="L820" class="LineNr"> 820 </span>
<span id="L821" class="LineNr"> 821 </span><span class="muScenario">scenario</span> editor-moves-cursor-to-previous-line-with-left-arrow-at-start-of-line-4 [
<span id="L822" class="LineNr"> 822 </span>  <span class="Constant">local-scope</span>
<span id="L823" class="LineNr"> 823 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L824" class="LineNr"> 824 </span>  <span class="Comment"># initialize editor with text containing an empty line</span>
<span id="L825" class="LineNr"> 825 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L826" class="LineNr"> 826 </span>
<span id="L827" class="LineNr"> 827 </span>d]
<span id="L828" class="LineNr"> 828 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L829" class="LineNr"> 829 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e:&amp;:editor
<span id="L830" class="LineNr"> 830 </span>  $clear-trace
<span id="L831" class="LineNr"> 831 </span>  <span class="Comment"># position cursor right after empty line</span>
<span id="L832" class="LineNr"> 832 </span>  assume-console [
<span id="L833" class="LineNr"> 833 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
<span id="L834" class="LineNr"> 834 </span>    press left-arrow
<span id="L835" class="LineNr"> 835 </span>    type <span class="Constant">[0]</span>
<span id="L836" class="LineNr"> 836 </span>  ]
<span id="L837" class="LineNr"> 837 </span>  run [
<span id="L838" class="LineNr"> 838 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L839" class="LineNr"> 839 </span>  ]
<span id="L840" class="LineNr"> 840 </span>  screen-should-contain [
<span id="L841" class="LineNr"> 841 </span>   <span class="Constant"> .          .</span>
<span id="L842" class="LineNr"> 842 </span>   <span class="Constant"> .abc       .</span>
<span id="L843" class="LineNr"> 843 </span>   <span class="Constant"> .0         .</span>
<span id="L844" class="LineNr"> 844 </span>   <span class="Constant"> .d         .</span>
<span id="L845" class="LineNr"> 845 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L846" class="LineNr"> 846 </span>  ]
<span id="L847" class="LineNr"> 847 </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="L848" class="LineNr"> 848 </span>]
<span id="L849" class="LineNr"> 849 </span>
<span id="L850" class="LineNr"> 850 </span><span class="muScenario">scenario</span> editor-moves-across-screen-lines-across-wrap-with-left-arrow [
<span id="L851" class="LineNr"> 851 </span>  <span class="Constant">local-scope</span>
<span id="L852" class="LineNr"> 852 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L853" class="LineNr"> 853 </span>  <span class="Comment"># initialize editor with a wrapping line</span>
<span id="L854" class="LineNr"> 854 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abcdef]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L855" class="LineNr"> 855 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L856" class="LineNr"> 856 </span>  $clear-trace
<span id="L857" class="LineNr"> 857 </span>  screen-should-contain [
<span id="L858" class="LineNr"> 858 </span>   <span class="Constant"> .          .</span>
<span id="L859" class="LineNr"> 859 </span>   <span class="Constant"> .abcd↩     .</span>
<span id="L860" class="LineNr"> 860 </span>   <span class="Constant"> .ef        .</span>
<span id="L861" class="LineNr"> 861 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L862" class="LineNr"> 862 </span>   <span class="Constant"> .          .</span>
<span id="L863" class="LineNr"> 863 </span>  ]
<span id="L864" class="LineNr"> 864 </span>  <span class="Comment"># position cursor right after empty line</span>
<span id="L865" class="LineNr"> 865 </span>  assume-console [
<span id="L866" class="LineNr"> 866 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
<span id="L867" class="LineNr"> 867 </span>    press left-arrow
<span id="L868" class="LineNr"> 868 </span>  ]
<span id="L869" class="LineNr"> 869 </span>  run [
<span id="L870" class="LineNr"> 870 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L871" class="LineNr"> 871 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L872" class="LineNr"> 872 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L873" class="LineNr"> 873 </span>  ]
<span id="L874" class="LineNr"> 874 </span>  memory-should-contain [
<span id="L875" class="LineNr"> 875 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># previous row</span>
<span id="L876" class="LineNr"> 876 </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="L877" class="LineNr"> 877 </span>  ]
<span id="L878" class="LineNr"> 878 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L879" class="LineNr"> 879 </span>]
<span id="L880" class="LineNr"> 880 </span>
<span id="L881" class="LineNr"> 881 </span><span class="muScenario">scenario</span> editor-moves-across-screen-lines-to-wrapping-line-with-left-arrow [
<span id="L882" class="LineNr"> 882 </span>  <span class="Constant">local-scope</span>
<span id="L883" class="LineNr"> 883 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L884" class="LineNr"> 884 </span>  <span class="Comment"># initialize editor with a wrapping line followed by a second line</span>
<span id="L885" class="LineNr"> 885 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abcdef</span>
<span id="L886" class="LineNr"> 886 </span><span class="Constant">g]</span>
<span id="L887" class="LineNr"> 887 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L888" class="LineNr"> 888 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L889" class="LineNr"> 889 </span>  $clear-trace
<span id="L890" class="LineNr"> 890 </span>  screen-should-contain [
<span id="L891" class="LineNr"> 891 </span>   <span class="Constant"> .          .</span>
<span id="L892" class="LineNr"> 892 </span>   <span class="Constant"> .abcd↩     .</span>
<span id="L893" class="LineNr"> 893 </span>   <span class="Constant"> .ef        .</span>
<span id="L894" class="LineNr"> 894 </span>   <span class="Constant"> .g         .</span>
<span id="L895" class="LineNr"> 895 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L896" class="LineNr"> 896 </span>  ]
<span id="L897" class="LineNr"> 897 </span>  <span class="Comment"># position cursor right after empty line</span>
<span id="L898" class="LineNr"> 898 </span>  assume-console [
<span id="L899" class="LineNr"> 899 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
<span id="L900" class="LineNr"> 900 </span>    press left-arrow
<span id="L901" class="LineNr"> 901 </span>  ]
<span id="L902" class="LineNr"> 902 </span>  run [
<span id="L903" class="LineNr"> 903 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<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>  ]
<span id="L907" class="LineNr"> 907 </span>  memory-should-contain [
<span id="L908" class="LineNr"> 908 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>  <span class="Comment"># previous row</span>
<span id="L909" class="LineNr"> 909 </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="L910" class="LineNr"> 910 </span>  ]
<span id="L911" class="LineNr"> 911 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L912" class="LineNr"> 912 </span>]
<span id="L913" class="LineNr"> 913 </span>
<span id="L914" class="LineNr"> 914 </span><span class="muScenario">scenario</span> editor-moves-across-screen-lines-to-non-wrapping-line-with-left-arrow [
<span id="L915" class="LineNr"> 915 </span>  <span class="Constant">local-scope</span>
<span id="L916" class="LineNr"> 916 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L917" class="LineNr"> 917 </span>  <span class="Comment"># initialize editor with a line on the verge of wrapping, followed by a second line</span>
<span id="L918" class="LineNr"> 918 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abcd</span>
<span id="L919" class="LineNr"> 919 </span><span class="Constant">e]</span>
<span id="L920" class="LineNr"> 920 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L921" class="LineNr"> 921 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L922" class="LineNr"> 922 </span>  $clear-trace
<span id="L923" class="LineNr"> 923 </span>  screen-should-contain [
<span id="L924" class="LineNr"> 924 </span>   <span class="Constant"> .          .</span>
<span id="L925" class="LineNr"> 925 </span>   <span class="Constant"> .abcd      .</span>
<span id="L926" class="LineNr"> 926 </span>   <span class="Constant"> .e         .</span>
<span id="L927" class="LineNr"> 927 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L928" class="LineNr"> 928 </span>   <span class="Constant"> .          .</span>
<span id="L929" class="LineNr"> 929 </span>  ]
<span id="L930" class="LineNr"> 930 </span>  <span class="Comment"># position cursor right after empty line</span>
<span id="L931" class="LineNr"> 931 </span>  assume-console [
<span id="L932" class="LineNr"> 932 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
<span id="L933" class="LineNr"> 933 </span>    press left-arrow
<span id="L934" class="LineNr"> 934 </span>  ]
<span id="L935" class="LineNr"> 935 </span>  run [
<span id="L936" class="LineNr"> 936 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L937" class="LineNr"> 937 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L938" class="LineNr"> 938 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L939" class="LineNr"> 939 </span>  ]
<span id="L940" class="LineNr"> 940 </span>  memory-should-contain [
<span id="L941" class="LineNr"> 941 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># previous row</span>
<span id="L942" class="LineNr"> 942 </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="L943" class="LineNr"> 943 </span>  ]
<span id="L944" class="LineNr"> 944 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L945" class="LineNr"> 945 </span>]
<span id="L946" class="LineNr"> 946 </span>
<span id="L947" class="LineNr"> 947 </span><span class="Comment"># todo: ctrl-left: previous word-start</span>
<span id="L948" class="LineNr"> 948 </span>
<span id="L949" class="LineNr"> 949 </span><span class="Comment"># up arrow</span>
<span id="L950" class="LineNr"> 950 </span>
<span id="L951" class="LineNr"> 951 </span><span class="muScenario">scenario</span> editor-moves-to-previous-line-with-up-arrow [
<span id="L952" class="LineNr"> 952 </span>  <span class="Constant">local-scope</span>
<span id="L953" class="LineNr"> 953 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L954" class="LineNr"> 954 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L955" class="LineNr"> 955 </span><span class="Constant">def]</span>
<span id="L956" class="LineNr"> 956 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L957" class="LineNr"> 957 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L958" class="LineNr"> 958 </span>  $clear-trace
<span id="L959" class="LineNr"> 959 </span>  assume-console [
<span id="L960" class="LineNr"> 960 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
<span id="L961" class="LineNr"> 961 </span>    press up-arrow
<span id="L962" class="LineNr"> 962 </span>  ]
<span id="L963" class="LineNr"> 963 </span>  run [
<span id="L964" class="LineNr"> 964 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L965" class="LineNr"> 965 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L966" class="LineNr"> 966 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L967" class="LineNr"> 967 </span>  ]
<span id="L968" class="LineNr"> 968 </span>  memory-should-contain [
<span id="L969" class="LineNr"> 969 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L970" class="LineNr"> 970 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L971" class="LineNr"> 971 </span>  ]
<span id="L972" class="LineNr"> 972 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L973" class="LineNr"> 973 </span>  assume-console [
<span id="L974" class="LineNr"> 974 </span>    type <span class="Constant">[0]</span>
<span id="L975" class="LineNr"> 975 </span>  ]
<span id="L976" class="LineNr"> 976 </span>  run [
<span id="L977" class="LineNr"> 977 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L978" class="LineNr"> 978 </span>  ]
<span id="L979" class="LineNr"> 979 </span>  screen-should-contain [
<span id="L980" class="LineNr"> 980 </span>   <span class="Constant"> .          .</span>
<span id="L981" class="LineNr"> 981 </span>   <span class="Constant"> .a0bc      .</span>
<span id="L982" class="LineNr"> 982 </span>   <span class="Constant"> .def       .</span>
<span id="L983" class="LineNr"> 983 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L984" class="LineNr"> 984 </span>   <span class="Constant"> .          .</span>
<span id="L985" class="LineNr"> 985 </span>  ]
<span id="L986" class="LineNr"> 986 </span>]
<span id="L987" class="LineNr"> 987 </span>
<span id="L988" class="LineNr"> 988 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L199'>&lt;handle-special-key&gt;</a></span> [
<span id="L989" class="LineNr"> 989 </span>  <span class="Delimiter">{</span>
<span id="L990" class="LineNr"> 990 </span>    move-to-previous-line?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65517/up-arrow</span>
<span id="L991" class="LineNr"> 991 </span>    <span class="muControl">break-unless</span> move-to-previous-line?
<span id="L992" class="LineNr"> 992 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L993" class="LineNr"> 993 </span>    go-render? <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1000'>move-to-previous-line</a> editor
<span id="L994" class="LineNr"> 994 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">3/up-arrow</span>
<span id="L995" class="LineNr"> 995 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L996" class="LineNr"> 996 </span>   <span class="muControl"> return</span>
<span id="L997" class="LineNr"> 997 </span>  <span class="Delimiter">}</span>
<span id="L998" class="LineNr"> 998 </span>]
<span id="L999" class="LineNr"> 999 </span>
<span id="L1000" class="LineNr">1000 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L1000'>move-to-previous-line</a> editor:&amp;:editor<span class="muRecipe"> -&gt; </span>go-render?:bool, editor:&amp;:editor [
<span id="L1001" class="LineNr">1001 </span>  <span class="Constant">local-scope</span>
<span id="L1002" class="LineNr">1002 </span>  <span class="Constant">load-inputs</span>
<span id="L1003" class="LineNr">1003 </span>  go-render?:bool <span class="Special">&lt;-</span> copy<span class="Constant"> false</span>
<span id="L1004" class="LineNr">1004 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L1005" class="LineNr">1005 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L1006" class="LineNr">1006 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L1007" class="LineNr">1007 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L1008" class="LineNr">1008 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L1009" class="LineNr">1009 </span>  already-at-top?:bool <span class="Special">&lt;-</span> lesser-or-equal cursor-row, <span class="Constant">1/top</span>
<span id="L1010" class="LineNr">1010 </span>  <span class="Delimiter">{</span>
<span id="L1011" class="LineNr">1011 </span>    <span class="Comment"># if cursor not at top, move it</span>
<span id="L1012" class="LineNr">1012 </span>    <span class="muControl">break-if</span> already-at-top?
<span id="L1013" class="LineNr">1013 </span>    <span class="Comment"># if not at start of screen line, move to start of screen line (previous newline)</span>
<span id="L1014" class="LineNr">1014 </span>    <span class="Comment"># then scan back another line</span>
<span id="L1015" class="LineNr">1015 </span>    <span class="Comment"># if either step fails, give up without modifying cursor or coordinates</span>
<span id="L1016" class="LineNr">1016 </span>    curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy before-cursor
<span id="L1017" class="LineNr">1017 </span>    old:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy curr
<span id="L1018" class="LineNr">1018 </span>    <span class="Delimiter">{</span>
<span id="L1019" class="LineNr">1019 </span>      at-left?:bool <span class="Special">&lt;-</span> equal cursor-column, left
<span id="L1020" class="LineNr">1020 </span>      <span class="muControl">break-if</span> at-left?
<span id="L1021" class="LineNr">1021 </span>      curr <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1067'>before-previous-screen-line</a> curr, editor
<span id="L1022" class="LineNr">1022 </span>      no-motion?:bool <span class="Special">&lt;-</span> equal curr, old
<span id="L1023" class="LineNr">1023 </span>      <span class="muControl">return-if</span> no-motion?
<span id="L1024" class="LineNr">1024 </span>    <span class="Delimiter">}</span>
<span id="L1025" class="LineNr">1025 </span>    <span class="Delimiter">{</span>
<span id="L1026" class="LineNr">1026 </span>      curr <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1067'>before-previous-screen-line</a> curr, editor
<span id="L1027" class="LineNr">1027 </span>      no-motion?:bool <span class="Special">&lt;-</span> equal curr, old
<span id="L1028" class="LineNr">1028 </span>      <span class="muControl">return-if</span> no-motion?
<span id="L1029" class="LineNr">1029 </span>    <span class="Delimiter">}</span>
<span id="L1030" class="LineNr">1030 </span>    before-cursor <span class="Special">&lt;-</span> copy curr
<span id="L1031" class="LineNr">1031 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L1032" class="LineNr">1032 </span>    cursor-row <span class="Special">&lt;-</span> subtract cursor-row,<span class="Constant"> 1</span>
<span id="L1033" class="LineNr">1033 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
<span id="L1034" class="LineNr">1034 </span>    <span class="Comment"># scan ahead to right column or until end of line</span>
<span id="L1035" class="LineNr">1035 </span>    target-column:num <span class="Special">&lt;-</span> copy cursor-column
<span id="L1036" class="LineNr">1036 </span>    cursor-column <span class="Special">&lt;-</span> copy left
<span id="L1037" class="LineNr">1037 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L1038" class="LineNr">1038 </span>    <span class="Delimiter">{</span>
<span id="L1039" class="LineNr">1039 </span>      done?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-column, target-column
<span id="L1040" class="LineNr">1040 </span>      <span class="muControl">break-if</span> done?
<span id="L1041" class="LineNr">1041 </span>      curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-cursor
<span id="L1042" class="LineNr">1042 </span>      <span class="muControl">break-unless</span> curr
<span id="L1043" class="LineNr">1043 </span>      currc:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
<span id="L1044" class="LineNr">1044 </span>      at-newline?:bool <span class="Special">&lt;-</span> equal currc, <span class="Constant">10/newline</span>
<span id="L1045" class="LineNr">1045 </span>      <span class="muControl">break-if</span> at-newline?
<span id="L1046" class="LineNr">1046 </span>      <span class="Comment">#</span>
<span id="L1047" class="LineNr">1047 </span>      before-cursor <span class="Special">&lt;-</span> copy curr
<span id="L1048" class="LineNr">1048 </span>      *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L1049" class="LineNr">1049 </span>      cursor-column <span class="Special">&lt;-</span> add cursor-column,<span class="Constant"> 1</span>
<span id="L1050" class="LineNr">1050 </span>      *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L1051" class="LineNr">1051 </span>     <span class="muControl"> loop</span>
<span id="L1052" class="LineNr">1052 </span>    <span class="Delimiter">}</span>
<span id="L1053" class="LineNr">1053 </span>   <span class="muControl"> return</span>
<span id="L1054" class="LineNr">1054 </span>  <span class="Delimiter">}</span>
<span id="L1055" class="LineNr">1055 </span>  <span class="Delimiter">{</span>
<span id="L1056" class="LineNr">1056 </span>    <span class="Comment"># if cursor already at top, scroll up</span>
<span id="L1057" class="LineNr">1057 </span>    <span class="muControl">break-unless</span> already-at-top?
<span id="L1058" class="LineNr">1058 </span><span class="Constant">    &lt;scroll-up&gt;</span>
<span id="L1059" class="LineNr">1059 </span>   <span class="muControl"> return</span><span class="Constant"> true/go-render</span>
<span id="L1060" class="LineNr">1060 </span>  <span class="Delimiter">}</span>
<span id="L1061" class="LineNr">1061 </span>]
<span id="L1062" class="LineNr">1062 </span>
<span id="L1063" class="LineNr">1063 </span><span class="Comment"># Takes a pointer into the doubly-linked list, scans back to before start of</span>
<span id="L1064" class="LineNr">1064 </span><span class="Comment"># previous *wrapped* line.</span>
<span id="L1065" class="LineNr">1065 </span><span class="Comment"># Returns original if no next newline.</span>
<span id="L1066" class="LineNr">1066 </span><span class="Comment"># Beware: never return null pointer.</span>
<span id="L1067" class="LineNr">1067 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L1067'>before-previous-screen-line</a> in:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char, editor:&amp;:editor<span class="muRecipe"> -&gt; </span>out:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char [
<span id="L1068" class="LineNr">1068 </span>  <span class="Constant">local-scope</span>
<span id="L1069" class="LineNr">1069 </span>  <span class="Constant">load-inputs</span>
<span id="L1070" class="LineNr">1070 </span>  curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy in
<span id="L1071" class="LineNr">1071 </span>  c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
<span id="L1072" class="LineNr">1072 </span>  <span class="Comment"># compute max, number of characters to skip</span>
<span id="L1073" class="LineNr">1073 </span>  <span class="Comment">#   1 + len%(width-1)</span>
<span id="L1074" class="LineNr">1074 </span>  <span class="Comment">#   except rotate second term to vary from 1 to width-1 rather than 0 to width-2</span>
<span id="L1075" class="LineNr">1075 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L1076" class="LineNr">1076 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L1077" class="LineNr">1077 </span>  max-line-length:num <span class="Special">&lt;-</span> subtract right, left, <span class="Constant">-1/exclusive-right</span>, <span class="Constant">1/wrap-icon</span>
<span id="L1078" class="LineNr">1078 </span>  sentinel:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
<span id="L1079" class="LineNr">1079 </span>  len:num <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L219'>previous-line-length</a> curr, sentinel
<span id="L1080" class="LineNr">1080 </span>  <span class="Delimiter">{</span>
<span id="L1081" class="LineNr">1081 </span>    <span class="muControl">break-if</span> len
<span id="L1082" class="LineNr">1082 </span>    <span class="Comment"># empty line; just skip this newline</span>
<span id="L1083" class="LineNr">1083 </span>    <a href='../065duplex_list.mu.html#L38'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L38'>prev</a> curr
<span id="L1084" class="LineNr">1084 </span>    <span class="muControl">return-unless</span> <a href='../065duplex_list.mu.html#L38'>prev</a>, curr
<span id="L1085" class="LineNr">1085 </span>   <span class="muControl"> return</span> <a href='../065duplex_list.mu.html#L38'>prev</a>
<span id="L1086" class="LineNr">1086 </span>  <span class="Delimiter">}</span>
<span id="L1087" class="LineNr">1087 </span>  _, max:num <span class="Special">&lt;-</span> divide-with-remainder len, max-line-length
<span id="L1088" class="LineNr">1088 </span>  <span class="Comment"># remainder 0 =&gt; scan one width-worth</span>
<span id="L1089" class="LineNr">1089 </span>  <span class="Delimiter">{</span>
<span id="L1090" class="LineNr">1090 </span>    <span class="muControl">break-if</span> max
<span id="L1091" class="LineNr">1091 </span>    max <span class="Special">&lt;-</span> copy max-line-length
<span id="L1092" class="LineNr">1092 </span>  <span class="Delimiter">}</span>
<span id="L1093" class="LineNr">1093 </span>  max <span class="Special">&lt;-</span> add max,<span class="Constant"> 1</span>
<span id="L1094" class="LineNr">1094 </span>  count:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
<span id="L1095" class="LineNr">1095 </span>  <span class="Comment"># skip 'max' characters</span>
<span id="L1096" class="LineNr">1096 </span>  <span class="Delimiter">{</span>
<span id="L1097" class="LineNr">1097 </span>    done?:bool <span class="Special">&lt;-</span> greater-or-equal count, max
<span id="L1098" class="LineNr">1098 </span>    <span class="muControl">break-if</span> done?
<span id="L1099" class="LineNr">1099 </span>    <a href='../065duplex_list.mu.html#L38'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L38'>prev</a> curr
<span id="L1100" class="LineNr">1100 </span>    <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L38'>prev</a>
<span id="L1101" class="LineNr">1101 </span>    curr <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L38'>prev</a>
<span id="L1102" class="LineNr">1102 </span>    count <span class="Special">&lt;-</span> add count,<span class="Constant"> 1</span>
<span id="L1103" class="LineNr">1103 </span>   <span class="muControl"> loop</span>
<span id="L1104" class="LineNr">1104 </span>  <span class="Delimiter">}</span>
<span id="L1105" class="LineNr">1105 </span> <span class="muControl"> return</span> curr
<span id="L1106" class="LineNr">1106 </span>]
<span id="L1107" class="LineNr">1107 </span>
<span id="L1108" class="LineNr">1108 </span><span class="muScenario">scenario</span> editor-adjusts-column-at-previous-line [
<span id="L1109" class="LineNr">1109 </span>  <span class="Constant">local-scope</span>
<span id="L1110" class="LineNr">1110 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1111" class="LineNr">1111 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[ab</span>
<span id="L1112" class="LineNr">1112 </span><span class="Constant">def]</span>
<span id="L1113" class="LineNr">1113 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1114" class="LineNr">1114 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1115" class="LineNr">1115 </span>  $clear-trace
<span id="L1116" class="LineNr">1116 </span>  assume-console [
<span id="L1117" class="LineNr">1117 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
<span id="L1118" class="LineNr">1118 </span>    press up-arrow
<span id="L1119" class="LineNr">1119 </span>  ]
<span id="L1120" class="LineNr">1120 </span>  run [
<span id="L1121" class="LineNr">1121 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1122" class="LineNr">1122 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1123" class="LineNr">1123 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1124" class="LineNr">1124 </span>  ]
<span id="L1125" class="LineNr">1125 </span>  memory-should-contain [
<span id="L1126" class="LineNr">1126 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1127" class="LineNr">1127 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1128" class="LineNr">1128 </span>  ]
<span id="L1129" class="LineNr">1129 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1130" class="LineNr">1130 </span>  assume-console [
<span id="L1131" class="LineNr">1131 </span>    type <span class="Constant">[0]</span>
<span id="L1132" class="LineNr">1132 </span>  ]
<span id="L1133" class="LineNr">1133 </span>  run [
<span id="L1134" class="LineNr">1134 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1135" class="LineNr">1135 </span>  ]
<span id="L1136" class="LineNr">1136 </span>  screen-should-contain [
<span id="L1137" class="LineNr">1137 </span>   <span class="Constant"> .          .</span>
<span id="L1138" class="LineNr">1138 </span>   <span class="Constant"> .ab0       .</span>
<span id="L1139" class="LineNr">1139 </span>   <span class="Constant"> .def       .</span>
<span id="L1140" class="LineNr">1140 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1141" class="LineNr">1141 </span>   <span class="Constant"> .          .</span>
<span id="L1142" class="LineNr">1142 </span>  ]
<span id="L1143" class="LineNr">1143 </span>]
<span id="L1144" class="LineNr">1144 </span>
<span id="L1145" class="LineNr">1145 </span><span class="muScenario">scenario</span> editor-adjusts-column-at-empty-line [
<span id="L1146" class="LineNr">1146 </span>  <span class="Constant">local-scope</span>
<span id="L1147" class="LineNr">1147 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1148" class="LineNr">1148 </span>  s:text <span class="Special">&lt;-</span> new [
<span id="L1149" class="LineNr">1149 </span><span class="muRecipe">def</span>]
<span id="L1150" class="LineNr">1150 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1151" class="LineNr">1151 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1152" class="LineNr">1152 </span>  $clear-trace
<span id="L1153" class="LineNr">1153 </span>  assume-console [
<span id="L1154" class="LineNr">1154 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
<span id="L1155" class="LineNr">1155 </span>    press up-arrow
<span id="L1156" class="LineNr">1156 </span>  ]
<span id="L1157" class="LineNr">1157 </span>  run [
<span id="L1158" class="LineNr">1158 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1159" class="LineNr">1159 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1160" class="LineNr">1160 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1161" class="LineNr">1161 </span>  ]
<span id="L1162" class="LineNr">1162 </span>  memory-should-contain [
<span id="L1163" class="LineNr">1163 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1164" class="LineNr">1164 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L1165" class="LineNr">1165 </span>  ]
<span id="L1166" class="LineNr">1166 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1167" class="LineNr">1167 </span>  assume-console [
<span id="L1168" class="LineNr">1168 </span>    type <span class="Constant">[0]</span>
<span id="L1169" class="LineNr">1169 </span>  ]
<span id="L1170" class="LineNr">1170 </span>  run [
<span id="L1171" class="LineNr">1171 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1172" class="LineNr">1172 </span>  ]
<span id="L1173" class="LineNr">1173 </span>  screen-should-contain [
<span id="L1174" class="LineNr">1174 </span>   <span class="Constant"> .          .</span>
<span id="L1175" class="LineNr">1175 </span>   <span class="Constant"> .0         .</span>
<span id="L1176" class="LineNr">1176 </span>   <span class="Constant"> .def       .</span>
<span id="L1177" class="LineNr">1177 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1178" class="LineNr">1178 </span>   <span class="Constant"> .          .</span>
<span id="L1179" class="LineNr">1179 </span>  ]
<span id="L1180" class="LineNr">1180 </span>]
<span id="L1181" class="LineNr">1181 </span>
<span id="L1182" class="LineNr">1182 </span><span class="muScenario">scenario</span> editor-moves-to-previous-line-from-zero-margin [
<span id="L1183" class="LineNr">1183 </span>  <span class="Constant">local-scope</span>
<span id="L1184" class="LineNr">1184 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1185" class="LineNr">1185 </span>  <span class="Comment"># start out with three lines</span>
<span id="L1186" class="LineNr">1186 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L1187" class="LineNr">1187 </span><span class="Constant">def</span>
<span id="L1188" class="LineNr">1188 </span><span class="Constant">ghi]</span>
<span id="L1189" class="LineNr">1189 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1190" class="LineNr">1190 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1191" class="LineNr">1191 </span>  $clear-trace
<span id="L1192" class="LineNr">1192 </span>  <span class="Comment"># click on the third line and hit up-arrow, so you end up just after a newline</span>
<span id="L1193" class="LineNr">1193 </span>  assume-console [
<span id="L1194" class="LineNr">1194 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
<span id="L1195" class="LineNr">1195 </span>    press up-arrow
<span id="L1196" class="LineNr">1196 </span>  ]
<span id="L1197" class="LineNr">1197 </span>  run [
<span id="L1198" class="LineNr">1198 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1199" class="LineNr">1199 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1200" class="LineNr">1200 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1201" class="LineNr">1201 </span>  ]
<span id="L1202" class="LineNr">1202 </span>  memory-should-contain [
<span id="L1203" class="LineNr">1203 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1204" class="LineNr">1204 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L1205" class="LineNr">1205 </span>  ]
<span id="L1206" class="LineNr">1206 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1207" class="LineNr">1207 </span>  assume-console [
<span id="L1208" class="LineNr">1208 </span>    type <span class="Constant">[0]</span>
<span id="L1209" class="LineNr">1209 </span>  ]
<span id="L1210" class="LineNr">1210 </span>  run [
<span id="L1211" class="LineNr">1211 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1212" class="LineNr">1212 </span>  ]
<span id="L1213" class="LineNr">1213 </span>  screen-should-contain [
<span id="L1214" class="LineNr">1214 </span>   <span class="Constant"> .          .</span>
<span id="L1215" class="LineNr">1215 </span>   <span class="Constant"> .abc       .</span>
<span id="L1216" class="LineNr">1216 </span>   <span class="Constant"> .0def      .</span>
<span id="L1217" class="LineNr">1217 </span>   <span class="Constant"> .ghi       .</span>
<span id="L1218" class="LineNr">1218 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1219" class="LineNr">1219 </span>  ]
<span id="L1220" class="LineNr">1220 </span>]
<span id="L1221" class="LineNr">1221 </span>
<span id="L1222" class="LineNr">1222 </span><span class="muScenario">scenario</span> editor-moves-to-previous-line-from-left-margin [
<span id="L1223" class="LineNr">1223 </span>  <span class="Constant">local-scope</span>
<span id="L1224" class="LineNr">1224 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1225" class="LineNr">1225 </span>  <span class="Comment"># start out with three lines</span>
<span id="L1226" class="LineNr">1226 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L1227" class="LineNr">1227 </span><span class="Constant">def</span>
<span id="L1228" class="LineNr">1228 </span><span class="Constant">ghi]</span>
<span id="L1229" class="LineNr">1229 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">1/left</span>, <span class="Constant">10/right</span>
<span id="L1230" class="LineNr">1230 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1231" class="LineNr">1231 </span>  $clear-trace
<span id="L1232" class="LineNr">1232 </span>  <span class="Comment"># click on the third line and hit up-arrow, so you end up just after a newline</span>
<span id="L1233" class="LineNr">1233 </span>  assume-console [
<span id="L1234" class="LineNr">1234 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 1</span>
<span id="L1235" class="LineNr">1235 </span>    press up-arrow
<span id="L1236" class="LineNr">1236 </span>  ]
<span id="L1237" class="LineNr">1237 </span>  run [
<span id="L1238" class="LineNr">1238 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1239" class="LineNr">1239 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1240" class="LineNr">1240 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1241" class="LineNr">1241 </span>  ]
<span id="L1242" class="LineNr">1242 </span>  memory-should-contain [
<span id="L1243" class="LineNr">1243 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1244" class="LineNr">1244 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1245" class="LineNr">1245 </span>  ]
<span id="L1246" class="LineNr">1246 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1247" class="LineNr">1247 </span>  assume-console [
<span id="L1248" class="LineNr">1248 </span>    type <span class="Constant">[0]</span>
<span id="L1249" class="LineNr">1249 </span>  ]
<span id="L1250" class="LineNr">1250 </span>  run [
<span id="L1251" class="LineNr">1251 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1252" class="LineNr">1252 </span>  ]
<span id="L1253" class="LineNr">1253 </span>  screen-should-contain [
<span id="L1254" class="LineNr">1254 </span>   <span class="Constant"> .          .</span>
<span id="L1255" class="LineNr">1255 </span>   <span class="Constant"> . abc      .</span>
<span id="L1256" class="LineNr">1256 </span>   <span class="Constant"> . 0def     .</span>
<span id="L1257" class="LineNr">1257 </span>   <span class="Constant"> . ghi      .</span>
<span id="L1258" class="LineNr">1258 </span>   <span class="Constant"> . ╌╌╌╌╌╌╌╌╌.</span>
<span id="L1259" class="LineNr">1259 </span>  ]
<span id="L1260" class="LineNr">1260 </span>]
<span id="L1261" class="LineNr">1261 </span>
<span id="L1262" class="LineNr">1262 </span><span class="muScenario">scenario</span> editor-moves-to-top-line-in-presence-of-wrapped-line [
<span id="L1263" class="LineNr">1263 </span>  <span class="Constant">local-scope</span>
<span id="L1264" class="LineNr">1264 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1265" class="LineNr">1265 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abcde]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L1266" class="LineNr">1266 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1267" class="LineNr">1267 </span>  screen-should-contain [
<span id="L1268" class="LineNr">1268 </span>   <span class="Constant"> .          .</span>
<span id="L1269" class="LineNr">1269 </span>   <span class="Constant"> .abcd↩     .</span>
<span id="L1270" class="LineNr">1270 </span>   <span class="Constant"> .e         .</span>
<span id="L1271" class="LineNr">1271 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L1272" class="LineNr">1272 </span>  ]
<span id="L1273" class="LineNr">1273 </span>  $clear-trace
<span id="L1274" class="LineNr">1274 </span>  assume-console [
<span id="L1275" class="LineNr">1275 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
<span id="L1276" class="LineNr">1276 </span>    press up-arrow
<span id="L1277" class="LineNr">1277 </span>  ]
<span id="L1278" class="LineNr">1278 </span>  run [
<span id="L1279" class="LineNr">1279 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1280" class="LineNr">1280 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1281" class="LineNr">1281 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1282" class="LineNr">1282 </span>  ]
<span id="L1283" class="LineNr">1283 </span>  memory-should-contain [
<span id="L1284" class="LineNr">1284 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1285" class="LineNr">1285 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L1286" class="LineNr">1286 </span>  ]
<span id="L1287" class="LineNr">1287 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1288" class="LineNr">1288 </span>  assume-console [
<span id="L1289" class="LineNr">1289 </span>    type <span class="Constant">[0]</span>
<span id="L1290" class="LineNr">1290 </span>  ]
<span id="L1291" class="LineNr">1291 </span>  run [
<span id="L1292" class="LineNr">1292 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1293" class="LineNr">1293 </span>  ]
<span id="L1294" class="LineNr">1294 </span>  screen-should-contain [
<span id="L1295" class="LineNr">1295 </span>   <span class="Constant"> .          .</span>
<span id="L1296" class="LineNr">1296 </span>   <span class="Constant"> .0abc↩     .</span>
<span id="L1297" class="LineNr">1297 </span>   <span class="Constant"> .de        .</span>
<span id="L1298" class="LineNr">1298 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L1299" class="LineNr">1299 </span>  ]
<span id="L1300" class="LineNr">1300 </span>]
<span id="L1301" class="LineNr">1301 </span>
<span id="L1302" class="LineNr">1302 </span><span class="muScenario">scenario</span> editor-moves-to-top-line-in-presence-of-wrapped-line-2 [
<span id="L1303" class="LineNr">1303 </span>  <span class="Constant">local-scope</span>
<span id="L1304" class="LineNr">1304 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1305" class="LineNr">1305 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L1306" class="LineNr">1306 </span><span class="Constant">defgh]</span>
<span id="L1307" class="LineNr">1307 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L1308" class="LineNr">1308 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1309" class="LineNr">1309 </span>  screen-should-contain [
<span id="L1310" class="LineNr">1310 </span>   <span class="Constant"> .          .</span>
<span id="L1311" class="LineNr">1311 </span>   <span class="Constant"> .abc       .</span>
<span id="L1312" class="LineNr">1312 </span>   <span class="Constant"> .defg↩     .</span>
<span id="L1313" class="LineNr">1313 </span>   <span class="Constant"> .h         .</span>
<span id="L1314" class="LineNr">1314 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L1315" class="LineNr">1315 </span>  ]
<span id="L1316" class="LineNr">1316 </span>  $clear-trace
<span id="L1317" class="LineNr">1317 </span>  assume-console [
<span id="L1318" class="LineNr">1318 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
<span id="L1319" class="LineNr">1319 </span>    press up-arrow
<span id="L1320" class="LineNr">1320 </span>    press up-arrow
<span id="L1321" class="LineNr">1321 </span>  ]
<span id="L1322" class="LineNr">1322 </span>  run [
<span id="L1323" class="LineNr">1323 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1324" class="LineNr">1324 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1325" class="LineNr">1325 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1326" class="LineNr">1326 </span>  ]
<span id="L1327" class="LineNr">1327 </span>  memory-should-contain [
<span id="L1328" class="LineNr">1328 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1329" class="LineNr">1329 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L1330" class="LineNr">1330 </span>  ]
<span id="L1331" class="LineNr">1331 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1332" class="LineNr">1332 </span>  assume-console [
<span id="L1333" class="LineNr">1333 </span>    type <span class="Constant">[0]</span>
<span id="L1334" class="LineNr">1334 </span>  ]
<span id="L1335" class="LineNr">1335 </span>  run [
<span id="L1336" class="LineNr">1336 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1337" class="LineNr">1337 </span>  ]
<span id="L1338" class="LineNr">1338 </span>  screen-should-contain [
<span id="L1339" class="LineNr">1339 </span>   <span class="Constant"> .          .</span>
<span id="L1340" class="LineNr">1340 </span>   <span class="Constant"> .0abc      .</span>
<span id="L1341" class="LineNr">1341 </span>   <span class="Constant"> .defg↩     .</span>
<span id="L1342" class="LineNr">1342 </span>   <span class="Constant"> .h         .</span>
<span id="L1343" class="LineNr">1343 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L1344" class="LineNr">1344 </span>  ]
<span id="L1345" class="LineNr">1345 </span>]
<span id="L1346" class="LineNr">1346 </span>
<span id="L1347" class="LineNr">1347 </span><span class="Comment"># down arrow</span>
<span id="L1348" class="LineNr">1348 </span>
<span id="L1349" class="LineNr">1349 </span><span class="muScenario">scenario</span> editor-moves-to-next-line-with-down-arrow [
<span id="L1350" class="LineNr">1350 </span>  <span class="Constant">local-scope</span>
<span id="L1351" class="LineNr">1351 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1352" class="LineNr">1352 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L1353" class="LineNr">1353 </span><span class="Constant">def]</span>
<span id="L1354" class="LineNr">1354 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1355" class="LineNr">1355 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1356" class="LineNr">1356 </span>  $clear-trace
<span id="L1357" class="LineNr">1357 </span>  <span class="Comment"># cursor starts out at (1, 0)</span>
<span id="L1358" class="LineNr">1358 </span>  assume-console [
<span id="L1359" class="LineNr">1359 </span>    press down-arrow
<span id="L1360" class="LineNr">1360 </span>  ]
<span id="L1361" class="LineNr">1361 </span>  run [
<span id="L1362" class="LineNr">1362 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1363" class="LineNr">1363 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1364" class="LineNr">1364 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1365" class="LineNr">1365 </span>  ]
<span id="L1366" class="LineNr">1366 </span>  <span class="Comment"># ..and ends at (2, 0)</span>
<span id="L1367" class="LineNr">1367 </span>  memory-should-contain [
<span id="L1368" class="LineNr">1368 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1369" class="LineNr">1369 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L1370" class="LineNr">1370 </span>  ]
<span id="L1371" class="LineNr">1371 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1372" class="LineNr">1372 </span>  assume-console [
<span id="L1373" class="LineNr">1373 </span>    type <span class="Constant">[0]</span>
<span id="L1374" class="LineNr">1374 </span>  ]
<span id="L1375" class="LineNr">1375 </span>  run [
<span id="L1376" class="LineNr">1376 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1377" class="LineNr">1377 </span>  ]
<span id="L1378" class="LineNr">1378 </span>  screen-should-contain [
<span id="L1379" class="LineNr">1379 </span>   <span class="Constant"> .          .</span>
<span id="L1380" class="LineNr">1380 </span>   <span class="Constant"> .abc       .</span>
<span id="L1381" class="LineNr">1381 </span>   <span class="Constant"> .0def      .</span>
<span id="L1382" class="LineNr">1382 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1383" class="LineNr">1383 </span>   <span class="Constant"> .          .</span>
<span id="L1384" class="LineNr">1384 </span>  ]
<span id="L1385" class="LineNr">1385 </span>]
<span id="L1386" class="LineNr">1386 </span>
<span id="L1387" class="LineNr">1387 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L199'>&lt;handle-special-key&gt;</a></span> [
<span id="L1388" class="LineNr">1388 </span>  <span class="Delimiter">{</span>
<span id="L1389" class="LineNr">1389 </span>    move-to-next-line?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65516/down-arrow</span>
<span id="L1390" class="LineNr">1390 </span>    <span class="muControl">break-unless</span> move-to-next-line?
<span id="L1391" class="LineNr">1391 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L1392" class="LineNr">1392 </span>    go-render? <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1399'>move-to-next-line</a> editor, <a href='../081print.mu.html#L782'>screen-height</a>
<span id="L1393" class="LineNr">1393 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">4/down-arrow</span>
<span id="L1394" class="LineNr">1394 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L1395" class="LineNr">1395 </span>   <span class="muControl"> return</span>
<span id="L1396" class="LineNr">1396 </span>  <span class="Delimiter">}</span>
<span id="L1397" class="LineNr">1397 </span>]
<span id="L1398" class="LineNr">1398 </span>
<span id="L1399" class="LineNr">1399 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L1399'>move-to-next-line</a> editor:&amp;:editor, <a href='../081print.mu.html#L782'>screen-height</a>:num<span class="muRecipe"> -&gt; </span>go-render?:bool, editor:&amp;:editor [
<span id="L1400" class="LineNr">1400 </span>  <span class="Constant">local-scope</span>
<span id="L1401" class="LineNr">1401 </span>  <span class="Constant">load-inputs</span>
<span id="L1402" class="LineNr">1402 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L1403" class="LineNr">1403 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L1404" class="LineNr">1404 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L1405" class="LineNr">1405 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L1406" class="LineNr">1406 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L1407" class="LineNr">1407 </span>  last-line:num <span class="Special">&lt;-</span> subtract <a href='../081print.mu.html#L782'>screen-height</a>,<span class="Constant"> 1</span>
<span id="L1408" class="LineNr">1408 </span>  bottom:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">bottom:offset</span>
<span id="L1409" class="LineNr">1409 </span>  at-bottom-of-screen?:bool <span class="Special">&lt;-</span> greater-or-equal bottom, last-line
<span id="L1410" class="LineNr">1410 </span>  <span class="Delimiter">{</span>
<span id="L1411" class="LineNr">1411 </span>    <span class="muControl">break-if</span> before-cursor
<span id="L1412" class="LineNr">1412 </span>    <span class="Delimiter">{</span>
<span id="L1413" class="LineNr">1413 </span>      <span class="muControl">break-if</span> at-bottom-of-screen?
<span id="L1414" class="LineNr">1414 </span>     <span class="muControl"> return</span><span class="Constant"> false/don't-render</span>
<span id="L1415" class="LineNr">1415 </span>    <span class="Delimiter">}</span>
<span id="L1416" class="LineNr">1416 </span>    <span class="Delimiter">{</span>
<span id="L1417" class="LineNr">1417 </span>      <span class="muControl">break-unless</span> at-bottom-of-screen?
<span id="L1418" class="LineNr">1418 </span>     <span class="muControl"> jump</span> <span class="Constant">+try-to-scroll</span>
<span id="L1419" class="LineNr">1419 </span>    <span class="Delimiter">}</span>
<span id="L1420" class="LineNr">1420 </span>  <span class="Delimiter">}</span>
<span id="L1421" class="LineNr">1421 </span>  <a href='../065duplex_list.mu.html#L31'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-cursor
<span id="L1422" class="LineNr">1422 </span>  <span class="Delimiter">{</span>
<span id="L1423" class="LineNr">1423 </span>    <span class="muControl">break-if</span> <a href='../065duplex_list.mu.html#L31'>next</a>
<span id="L1424" class="LineNr">1424 </span>    <span class="Delimiter">{</span>
<span id="L1425" class="LineNr">1425 </span>      <span class="muControl">break-if</span> at-bottom-of-screen?
<span id="L1426" class="LineNr">1426 </span>     <span class="muControl"> return</span><span class="Constant"> false/don't-render</span>
<span id="L1427" class="LineNr">1427 </span>    <span class="Delimiter">}</span>
<span id="L1428" class="LineNr">1428 </span>    <span class="Delimiter">{</span>
<span id="L1429" class="LineNr">1429 </span>      <span class="muControl">break-unless</span> at-bottom-of-screen?
<span id="L1430" class="LineNr">1430 </span>     <span class="muControl"> jump</span> <span class="Constant">+try-to-scroll</span>
<span id="L1431" class="LineNr">1431 </span>    <span class="Delimiter">}</span>
<span id="L1432" class="LineNr">1432 </span>  <span class="Delimiter">}</span>
<span id="L1433" class="LineNr">1433 </span>  already-at-bottom?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-row, last-line
<span id="L1434" class="LineNr">1434 </span>  <span class="Delimiter">{</span>
<span id="L1435" class="LineNr">1435 </span>    <span class="Comment"># if cursor not at bottom, move it</span>
<span id="L1436" class="LineNr">1436 </span>    <span class="muControl">break-if</span> already-at-bottom?
<span id="L1437" class="LineNr">1437 </span>    target-column:num <span class="Special">&lt;-</span> copy cursor-column
<span id="L1438" class="LineNr">1438 </span>    <span class="Comment"># scan to start of next line</span>
<span id="L1439" class="LineNr">1439 </span>    <span class="Delimiter">{</span>
<span id="L1440" class="LineNr">1440 </span>      <a href='../065duplex_list.mu.html#L31'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-cursor
<span id="L1441" class="LineNr">1441 </span>      <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L31'>next</a>
<span id="L1442" class="LineNr">1442 </span>      done?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-column, right
<span id="L1443" class="LineNr">1443 </span>      <span class="muControl">break-if</span> done?
<span id="L1444" class="LineNr">1444 </span>      cursor-column <span class="Special">&lt;-</span> add cursor-column,<span class="Constant"> 1</span>
<span id="L1445" class="LineNr">1445 </span>      before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L31'>next</a>
<span id="L1446" class="LineNr">1446 </span>      c:char <span class="Special">&lt;-</span> get *next, <span class="Constant">value:offset</span>
<span id="L1447" class="LineNr">1447 </span>      at-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
<span id="L1448" class="LineNr">1448 </span>      <span class="muControl">break-if</span> at-newline?
<span id="L1449" class="LineNr">1449 </span>     <span class="muControl"> loop</span>
<span id="L1450" class="LineNr">1450 </span>    <span class="Delimiter">}</span>
<span id="L1451" class="LineNr">1451 </span>    <span class="Delimiter">{</span>
<span id="L1452" class="LineNr">1452 </span>      <span class="muControl">break-if</span> <a href='../065duplex_list.mu.html#L31'>next</a>
<span id="L1453" class="LineNr">1453 </span>      <span class="Delimiter">{</span>
<span id="L1454" class="LineNr">1454 </span>        <span class="muControl">break-if</span> at-bottom-of-screen?
<span id="L1455" class="LineNr">1455 </span>       <span class="muControl"> return</span><span class="Constant"> false/don't-render</span>
<span id="L1456" class="LineNr">1456 </span>      <span class="Delimiter">}</span>
<span id="L1457" class="LineNr">1457 </span>      <span class="Delimiter">{</span>
<span id="L1458" class="LineNr">1458 </span>        <span class="muControl">break-unless</span> at-bottom-of-screen?
<span id="L1459" class="LineNr">1459 </span>       <span class="muControl"> jump</span> <span class="Constant">+try-to-scroll</span>
<span id="L1460" class="LineNr">1460 </span>      <span class="Delimiter">}</span>
<span id="L1461" class="LineNr">1461 </span>    <span class="Delimiter">}</span>
<span id="L1462" class="LineNr">1462 </span>    cursor-row <span class="Special">&lt;-</span> add cursor-row,<span class="Constant"> 1</span>
<span id="L1463" class="LineNr">1463 </span>    cursor-column <span class="Special">&lt;-</span> copy left
<span id="L1464" class="LineNr">1464 </span>    <span class="Delimiter">{</span>
<span id="L1465" class="LineNr">1465 </span>      <a href='../065duplex_list.mu.html#L31'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-cursor
<span id="L1466" class="LineNr">1466 </span>      <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L31'>next</a>
<span id="L1467" class="LineNr">1467 </span>      c:char <span class="Special">&lt;-</span> get *next, <span class="Constant">value:offset</span>
<span id="L1468" class="LineNr">1468 </span>      at-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
<span id="L1469" class="LineNr">1469 </span>      <span class="muControl">break-if</span> at-newline?
<span id="L1470" class="LineNr">1470 </span>      done?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-column, target-column
<span id="L1471" class="LineNr">1471 </span>      <span class="muControl">break-if</span> done?
<span id="L1472" class="LineNr">1472 </span>      cursor-column <span class="Special">&lt;-</span> add cursor-column,<span class="Constant"> 1</span>
<span id="L1473" class="LineNr">1473 </span>      before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L31'>next</a>
<span id="L1474" class="LineNr">1474 </span>     <span class="muControl"> loop</span>
<span id="L1475" class="LineNr">1475 </span>    <span class="Delimiter">}</span>
<span id="L1476" class="LineNr">1476 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L1477" class="LineNr">1477 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L1478" class="LineNr">1478 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
<span id="L1479" class="LineNr">1479 </span>   <span class="muControl"> return</span><span class="Constant"> false/don't-render</span>
<span id="L1480" class="LineNr">1480 </span>  <span class="Delimiter">}</span>
<span id="L1481" class="LineNr">1481 </span><span class="Constant">  +try-to-scroll</span>
<span id="L1482" class="LineNr">1482 </span><span class="Constant">  &lt;scroll-down&gt;</span>
<span id="L1483" class="LineNr">1483 </span>  go-render? <span class="Special">&lt;-</span> copy<span class="Constant"> true</span>
<span id="L1484" class="LineNr">1484 </span>]
<span id="L1485" class="LineNr">1485 </span>
<span id="L1486" class="LineNr">1486 </span><span class="muScenario">scenario</span> editor-adjusts-column-at-next-line [
<span id="L1487" class="LineNr">1487 </span>  <span class="Constant">local-scope</span>
<span id="L1488" class="LineNr">1488 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1489" class="LineNr">1489 </span>  <span class="Comment"># second line is shorter than first</span>
<span id="L1490" class="LineNr">1490 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abcde</span>
<span id="L1491" class="LineNr">1491 </span><span class="Constant">fg</span>
<span id="L1492" class="LineNr">1492 </span><span class="Constant">hi]</span>
<span id="L1493" class="LineNr">1493 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1494" class="LineNr">1494 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1495" class="LineNr">1495 </span>  $clear-trace
<span id="L1496" class="LineNr">1496 </span>  <span class="Comment"># move to end of first line, then press down</span>
<span id="L1497" class="LineNr">1497 </span>  assume-console [
<span id="L1498" class="LineNr">1498 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 8</span>
<span id="L1499" class="LineNr">1499 </span>    press down-arrow
<span id="L1500" class="LineNr">1500 </span>  ]
<span id="L1501" class="LineNr">1501 </span>  run [
<span id="L1502" class="LineNr">1502 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1503" class="LineNr">1503 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1504" class="LineNr">1504 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1505" class="LineNr">1505 </span>  ]
<span id="L1506" class="LineNr">1506 </span>  <span class="Comment"># cursor doesn't go vertically down, it goes to end of shorter line</span>
<span id="L1507" class="LineNr">1507 </span>  memory-should-contain [
<span id="L1508" class="LineNr">1508 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1509" class="LineNr">1509 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1510" class="LineNr">1510 </span>  ]
<span id="L1511" class="LineNr">1511 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1512" class="LineNr">1512 </span>  assume-console [
<span id="L1513" class="LineNr">1513 </span>    type <span class="Constant">[0]</span>
<span id="L1514" class="LineNr">1514 </span>  ]
<span id="L1515" class="LineNr">1515 </span>  run [
<span id="L1516" class="LineNr">1516 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1517" class="LineNr">1517 </span>  ]
<span id="L1518" class="LineNr">1518 </span>  screen-should-contain [
<span id="L1519" class="LineNr">1519 </span>   <span class="Constant"> .          .</span>
<span id="L1520" class="LineNr">1520 </span>   <span class="Constant"> .abcde     .</span>
<span id="L1521" class="LineNr">1521 </span>   <span class="Constant"> .fg0       .</span>
<span id="L1522" class="LineNr">1522 </span>   <span class="Constant"> .hi        .</span>
<span id="L1523" class="LineNr">1523 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1524" class="LineNr">1524 </span>  ]
<span id="L1525" class="LineNr">1525 </span>]
<span id="L1526" class="LineNr">1526 </span>
<span id="L1527" class="LineNr">1527 </span><span class="muScenario">scenario</span> editor-moves-down-within-wrapped-line [
<span id="L1528" class="LineNr">1528 </span>  <span class="Constant">local-scope</span>
<span id="L1529" class="LineNr">1529 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1530" class="LineNr">1530 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abcdefghijklmno]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1531" class="LineNr">1531 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1532" class="LineNr">1532 </span>  screen-should-contain [
<span id="L1533" class="LineNr">1533 </span>   <span class="Constant"> .          .</span>
<span id="L1534" class="LineNr">1534 </span><span class="Constant">    .abcdefghi↩.</span>
<span id="L1535" class="LineNr">1535 </span>   <span class="Constant"> .jklmno    .</span>
<span id="L1536" class="LineNr">1536 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1537" class="LineNr">1537 </span>   <span class="Constant"> .          .</span>
<span id="L1538" class="LineNr">1538 </span>  ]
<span id="L1539" class="LineNr">1539 </span>  <span class="Comment"># position cursor on first screen line, but past end of second screen line</span>
<span id="L1540" class="LineNr">1540 </span>  assume-console [
<span id="L1541" class="LineNr">1541 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 8</span>
<span id="L1542" class="LineNr">1542 </span>    press down-arrow
<span id="L1543" class="LineNr">1543 </span>  ]
<span id="L1544" class="LineNr">1544 </span>  run [
<span id="L1545" class="LineNr">1545 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1546" class="LineNr">1546 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1547" class="LineNr">1547 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1548" class="LineNr">1548 </span>  ]
<span id="L1549" class="LineNr">1549 </span>  <span class="Comment"># cursor should be at end of second screen line</span>
<span id="L1550" class="LineNr">1550 </span>  memory-should-contain [
<span id="L1551" class="LineNr">1551 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1552" class="LineNr">1552 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 6</span>
<span id="L1553" class="LineNr">1553 </span>  ]
<span id="L1554" class="LineNr">1554 </span>]
<span id="L1555" class="LineNr">1555 </span>
<span id="L1556" class="LineNr">1556 </span><span class="Comment"># ctrl-a/home - move cursor to start of line</span>
<span id="L1557" class="LineNr">1557 </span>
<span id="L1558" class="LineNr">1558 </span><span class="muScenario">scenario</span> editor-moves-to-start-of-line-with-ctrl-a [
<span id="L1559" class="LineNr">1559 </span>  <span class="Constant">local-scope</span>
<span id="L1560" class="LineNr">1560 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1561" class="LineNr">1561 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L1562" class="LineNr">1562 </span><span class="Constant">456]</span>
<span id="L1563" class="LineNr">1563 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1564" class="LineNr">1564 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1565" class="LineNr">1565 </span>  $clear-trace
<span id="L1566" class="LineNr">1566 </span>  <span class="Comment"># start on second line, press ctrl-a</span>
<span id="L1567" class="LineNr">1567 </span>  assume-console [
<span id="L1568" class="LineNr">1568 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
<span id="L1569" class="LineNr">1569 </span>    press ctrl-a
<span id="L1570" class="LineNr">1570 </span>  ]
<span id="L1571" class="LineNr">1571 </span>  run [
<span id="L1572" class="LineNr">1572 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1573" class="LineNr">1573 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1574" class="LineNr">1574 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1575" class="LineNr">1575 </span>  ]
<span id="L1576" class="LineNr">1576 </span>  <span class="Comment"># cursor moves to start of line</span>
<span id="L1577" class="LineNr">1577 </span>  memory-should-contain [
<span id="L1578" class="LineNr">1578 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1579" class="LineNr">1579 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L1580" class="LineNr">1580 </span>  ]
<span id="L1581" class="LineNr">1581 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1582" class="LineNr">1582 </span>]
<span id="L1583" class="LineNr">1583 </span>
<span id="L1584" class="LineNr">1584 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L1585" class="LineNr">1585 </span>  <span class="Delimiter">{</span>
<span id="L1586" class="LineNr">1586 </span>    move-to-start-of-line?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">1/ctrl-a</span>
<span id="L1587" class="LineNr">1587 </span>    <span class="muControl">break-unless</span> move-to-start-of-line?
<span id="L1588" class="LineNr">1588 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L1589" class="LineNr">1589 </span>    <a href='003-shortcuts.mu.html#L1610'>move-to-start-of-screen-line</a> editor
<span id="L1590" class="LineNr">1590 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
<span id="L1591" class="LineNr">1591 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L1592" class="LineNr">1592 </span>   <span class="muControl"> return</span><span class="Constant"> false/don't-render</span>
<span id="L1593" class="LineNr">1593 </span>  <span class="Delimiter">}</span>
<span id="L1594" class="LineNr">1594 </span>]
<span id="L1595" class="LineNr">1595 </span>
<span id="L1596" class="LineNr">1596 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L199'>&lt;handle-special-key&gt;</a></span> [
<span id="L1597" class="LineNr">1597 </span>  <span class="Delimiter">{</span>
<span id="L1598" class="LineNr">1598 </span>    move-to-start-of-line?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65521/home</span>
<span id="L1599" class="LineNr">1599 </span>    <span class="muControl">break-unless</span> move-to-start-of-line?
<span id="L1600" class="LineNr">1600 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L1601" class="LineNr">1601 </span>    <a href='003-shortcuts.mu.html#L1610'>move-to-start-of-screen-line</a> editor
<span id="L1602" class="LineNr">1602 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
<span id="L1603" class="LineNr">1603 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L1604" class="LineNr">1604 </span>   <span class="muControl"> return</span><span class="Constant"> false/don't-render</span>
<span id="L1605" class="LineNr">1605 </span>  <span class="Delimiter">}</span>
<span id="L1606" class="LineNr">1606 </span>]
<span id="L1607" class="LineNr">1607 </span>
<span id="L1608" class="LineNr">1608 </span><span class="Comment"># handles wrapped lines</span>
<span id="L1609" class="LineNr">1609 </span><span class="Comment"># precondition: cursor-column should be in a consistent state</span>
<span id="L1610" class="LineNr">1610 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L1610'>move-to-start-of-screen-line</a> editor:&amp;:editor<span class="muRecipe"> -&gt; </span>editor:&amp;:editor [
<span id="L1611" class="LineNr">1611 </span>  <span class="Constant">local-scope</span>
<span id="L1612" class="LineNr">1612 </span>  <span class="Constant">load-inputs</span>
<span id="L1613" class="LineNr">1613 </span>  <span class="Comment"># update cursor column</span>
<span id="L1614" class="LineNr">1614 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L1615" class="LineNr">1615 </span>  col:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L1616" class="LineNr">1616 </span>  <span class="Comment"># update before-cursor</span>
<span id="L1617" class="LineNr">1617 </span>  curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L1618" class="LineNr">1618 </span>  <span class="Comment"># while not at start of line, move</span>
<span id="L1619" class="LineNr">1619 </span>  <span class="Delimiter">{</span>
<span id="L1620" class="LineNr">1620 </span>    done?:bool <span class="Special">&lt;-</span> equal col, left
<span id="L1621" class="LineNr">1621 </span>    <span class="muControl">break-if</span> done?
<span id="L1622" class="LineNr">1622 </span>    assert curr, <span class="Constant">[move-to-start-of-line tried to move before start of text]</span>
<span id="L1623" class="LineNr">1623 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L38'>prev</a> curr
<span id="L1624" class="LineNr">1624 </span>    col <span class="Special">&lt;-</span> subtract col,<span class="Constant"> 1</span>
<span id="L1625" class="LineNr">1625 </span>   <span class="muControl"> loop</span>
<span id="L1626" class="LineNr">1626 </span>  <span class="Delimiter">}</span>
<span id="L1627" class="LineNr">1627 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, col
<span id="L1628" class="LineNr">1628 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, curr
<span id="L1629" class="LineNr">1629 </span>]
<span id="L1630" class="LineNr">1630 </span>
<span id="L1631" class="LineNr">1631 </span><span class="muScenario">scenario</span> editor-moves-to-start-of-line-with-ctrl-a-2 [
<span id="L1632" class="LineNr">1632 </span>  <span class="Constant">local-scope</span>
<span id="L1633" class="LineNr">1633 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1634" class="LineNr">1634 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L1635" class="LineNr">1635 </span><span class="Constant">456]</span>
<span id="L1636" class="LineNr">1636 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1637" class="LineNr">1637 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1638" class="LineNr">1638 </span>  $clear-trace
<span id="L1639" class="LineNr">1639 </span>  <span class="Comment"># start on first line (no newline before), press ctrl-a</span>
<span id="L1640" class="LineNr">1640 </span>  assume-console [
<span id="L1641" class="LineNr">1641 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
<span id="L1642" class="LineNr">1642 </span>    press ctrl-a
<span id="L1643" class="LineNr">1643 </span>  ]
<span id="L1644" class="LineNr">1644 </span>  run [
<span id="L1645" class="LineNr">1645 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1646" class="LineNr">1646 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1647" class="LineNr">1647 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1648" class="LineNr">1648 </span>  ]
<span id="L1649" class="LineNr">1649 </span>  <span class="Comment"># cursor moves to start of line</span>
<span id="L1650" class="LineNr">1650 </span>  memory-should-contain [
<span id="L1651" class="LineNr">1651 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1652" class="LineNr">1652 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L1653" class="LineNr">1653 </span>  ]
<span id="L1654" class="LineNr">1654 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1655" class="LineNr">1655 </span>]
<span id="L1656" class="LineNr">1656 </span>
<span id="L1657" class="LineNr">1657 </span><span class="muScenario">scenario</span> editor-moves-to-start-of-line-with-home [
<span id="L1658" class="LineNr">1658 </span>  <span class="Constant">local-scope</span>
<span id="L1659" class="LineNr">1659 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1660" class="LineNr">1660 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L1661" class="LineNr">1661 </span><span class="Constant">456]</span>
<span id="L1662" class="LineNr">1662 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1663" class="LineNr">1663 </span>  $clear-trace
<span id="L1664" class="LineNr">1664 </span>  <span class="Comment"># start on second line, press 'home'</span>
<span id="L1665" class="LineNr">1665 </span>  assume-console [
<span id="L1666" class="LineNr">1666 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
<span id="L1667" class="LineNr">1667 </span>    press home
<span id="L1668" class="LineNr">1668 </span>  ]
<span id="L1669" class="LineNr">1669 </span>  run [
<span id="L1670" class="LineNr">1670 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1671" class="LineNr">1671 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1672" class="LineNr">1672 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1673" class="LineNr">1673 </span>  ]
<span id="L1674" class="LineNr">1674 </span>  <span class="Comment"># cursor moves to start of line</span>
<span id="L1675" class="LineNr">1675 </span>  memory-should-contain [
<span id="L1676" class="LineNr">1676 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1677" class="LineNr">1677 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L1678" class="LineNr">1678 </span>  ]
<span id="L1679" class="LineNr">1679 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1680" class="LineNr">1680 </span>]
<span id="L1681" class="LineNr">1681 </span>
<span id="L1682" class="LineNr">1682 </span><span class="muScenario">scenario</span> editor-moves-to-start-of-line-with-home-2 [
<span id="L1683" class="LineNr">1683 </span>  <span class="Constant">local-scope</span>
<span id="L1684" class="LineNr">1684 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1685" class="LineNr">1685 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L1686" class="LineNr">1686 </span><span class="Constant">456]</span>
<span id="L1687" class="LineNr">1687 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1688" class="LineNr">1688 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1689" class="LineNr">1689 </span>  $clear-trace
<span id="L1690" class="LineNr">1690 </span>  <span class="Comment"># start on first line (no newline before), press 'home'</span>
<span id="L1691" class="LineNr">1691 </span>  assume-console [
<span id="L1692" class="LineNr">1692 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
<span id="L1693" class="LineNr">1693 </span>    press home
<span id="L1694" class="LineNr">1694 </span>  ]
<span id="L1695" class="LineNr">1695 </span>  run [
<span id="L1696" class="LineNr">1696 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1697" class="LineNr">1697 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1698" class="LineNr">1698 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1699" class="LineNr">1699 </span>  ]
<span id="L1700" class="LineNr">1700 </span>  <span class="Comment"># cursor moves to start of line</span>
<span id="L1701" class="LineNr">1701 </span>  memory-should-contain [
<span id="L1702" class="LineNr">1702 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1703" class="LineNr">1703 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L1704" class="LineNr">1704 </span>  ]
<span id="L1705" class="LineNr">1705 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1706" class="LineNr">1706 </span>]
<span id="L1707" class="LineNr">1707 </span>
<span id="L1708" class="LineNr">1708 </span><span class="muScenario">scenario</span> editor-moves-to-start-of-screen-line-with-ctrl-a [
<span id="L1709" class="LineNr">1709 </span>  <span class="Constant">local-scope</span>
<span id="L1710" class="LineNr">1710 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1711" class="LineNr">1711 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[123456]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L1712" class="LineNr">1712 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1713" class="LineNr">1713 </span>  screen-should-contain [
<span id="L1714" class="LineNr">1714 </span>   <span class="Constant"> .          .</span>
<span id="L1715" class="LineNr">1715 </span>   <span class="Constant"> .1234↩     .</span>
<span id="L1716" class="LineNr">1716 </span>   <span class="Constant"> .56        .</span>
<span id="L1717" class="LineNr">1717 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L1718" class="LineNr">1718 </span>   <span class="Constant"> .          .</span>
<span id="L1719" class="LineNr">1719 </span>  ]
<span id="L1720" class="LineNr">1720 </span>  $clear-trace
<span id="L1721" class="LineNr">1721 </span>  <span class="Comment"># start on second line, press ctrl-a then up</span>
<span id="L1722" class="LineNr">1722 </span>  assume-console [
<span id="L1723" class="LineNr">1723 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
<span id="L1724" class="LineNr">1724 </span>    press ctrl-a
<span id="L1725" class="LineNr">1725 </span>    press up-arrow
<span id="L1726" class="LineNr">1726 </span>  ]
<span id="L1727" class="LineNr">1727 </span>  run [
<span id="L1728" class="LineNr">1728 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1729" class="LineNr">1729 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1730" class="LineNr">1730 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1731" class="LineNr">1731 </span>  ]
<span id="L1732" class="LineNr">1732 </span>  <span class="Comment"># cursor moves to start of first line</span>
<span id="L1733" class="LineNr">1733 </span>  memory-should-contain [
<span id="L1734" class="LineNr">1734 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># cursor-row</span>
<span id="L1735" class="LineNr">1735 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># cursor-column</span>
<span id="L1736" class="LineNr">1736 </span>  ]
<span id="L1737" class="LineNr">1737 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1738" class="LineNr">1738 </span>  <span class="Comment"># make sure before-cursor is in sync</span>
<span id="L1739" class="LineNr">1739 </span>  assume-console [
<span id="L1740" class="LineNr">1740 </span>    type <span class="Constant">[a]</span>
<span id="L1741" class="LineNr">1741 </span>  ]
<span id="L1742" class="LineNr">1742 </span>  run [
<span id="L1743" class="LineNr">1743 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1744" class="LineNr">1744 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1745" class="LineNr">1745 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1746" class="LineNr">1746 </span>  ]
<span id="L1747" class="LineNr">1747 </span>  screen-should-contain [
<span id="L1748" class="LineNr">1748 </span>   <span class="Constant"> .          .</span>
<span id="L1749" class="LineNr">1749 </span>   <span class="Constant"> .a123↩     .</span>
<span id="L1750" class="LineNr">1750 </span>   <span class="Constant"> .456       .</span>
<span id="L1751" class="LineNr">1751 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L1752" class="LineNr">1752 </span>   <span class="Constant"> .          .</span>
<span id="L1753" class="LineNr">1753 </span>  ]
<span id="L1754" class="LineNr">1754 </span>  memory-should-contain [
<span id="L1755" class="LineNr">1755 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># cursor-row</span>
<span id="L1756" class="LineNr">1756 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># cursor-column</span>
<span id="L1757" class="LineNr">1757 </span>  ]
<span id="L1758" class="LineNr">1758 </span>]
<span id="L1759" class="LineNr">1759 </span>
<span id="L1760" class="LineNr">1760 </span><span class="Comment"># ctrl-e/end - move cursor to end of line</span>
<span id="L1761" class="LineNr">1761 </span>
<span id="L1762" class="LineNr">1762 </span><span class="muScenario">scenario</span> editor-moves-to-end-of-line-with-ctrl-e [
<span id="L1763" class="LineNr">1763 </span>  <span class="Constant">local-scope</span>
<span id="L1764" class="LineNr">1764 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1765" class="LineNr">1765 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L1766" class="LineNr">1766 </span><span class="Constant">456]</span>
<span id="L1767" class="LineNr">1767 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1768" class="LineNr">1768 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1769" class="LineNr">1769 </span>  $clear-trace
<span id="L1770" class="LineNr">1770 </span>  <span class="Comment"># start on first line, press ctrl-e</span>
<span id="L1771" class="LineNr">1771 </span>  assume-console [
<span id="L1772" class="LineNr">1772 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
<span id="L1773" class="LineNr">1773 </span>    press ctrl-e
<span id="L1774" class="LineNr">1774 </span>  ]
<span id="L1775" class="LineNr">1775 </span>  run [
<span id="L1776" class="LineNr">1776 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1777" class="LineNr">1777 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1778" class="LineNr">1778 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1779" class="LineNr">1779 </span>  ]
<span id="L1780" class="LineNr">1780 </span>  <span class="Comment"># cursor moves to end of line</span>
<span id="L1781" class="LineNr">1781 </span>  memory-should-contain [
<span id="L1782" class="LineNr">1782 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1783" class="LineNr">1783 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L1784" class="LineNr">1784 </span>  ]
<span id="L1785" class="LineNr">1785 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1786" class="LineNr">1786 </span>  <span class="Comment"># editor inserts future characters at cursor</span>
<span id="L1787" class="LineNr">1787 </span>  assume-console [
<span id="L1788" class="LineNr">1788 </span>    type <span class="Constant">[z]</span>
<span id="L1789" class="LineNr">1789 </span>  ]
<span id="L1790" class="LineNr">1790 </span>  run [
<span id="L1791" class="LineNr">1791 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1792" class="LineNr">1792 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1793" class="LineNr">1793 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1794" class="LineNr">1794 </span>  ]
<span id="L1795" class="LineNr">1795 </span>  memory-should-contain [
<span id="L1796" class="LineNr">1796 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1797" class="LineNr">1797 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
<span id="L1798" class="LineNr">1798 </span>  ]
<span id="L1799" class="LineNr">1799 </span>  screen-should-contain [
<span id="L1800" class="LineNr">1800 </span>   <span class="Constant"> .          .</span>
<span id="L1801" class="LineNr">1801 </span>   <span class="Constant"> .123z      .</span>
<span id="L1802" class="LineNr">1802 </span>   <span class="Constant"> .456       .</span>
<span id="L1803" class="LineNr">1803 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1804" class="LineNr">1804 </span>   <span class="Constant"> .          .</span>
<span id="L1805" class="LineNr">1805 </span>  ]
<span id="L1806" class="LineNr">1806 </span>  check-trace-count-for-label<span class="Constant"> 1</span>, <span class="Constant">[print-character]</span>
<span id="L1807" class="LineNr">1807 </span>]
<span id="L1808" class="LineNr">1808 </span>
<span id="L1809" class="LineNr">1809 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L1810" class="LineNr">1810 </span>  <span class="Delimiter">{</span>
<span id="L1811" class="LineNr">1811 </span>    move-to-end-of-line?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">5/ctrl-e</span>
<span id="L1812" class="LineNr">1812 </span>    <span class="muControl">break-unless</span> move-to-end-of-line?
<span id="L1813" class="LineNr">1813 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L1814" class="LineNr">1814 </span>    <a href='003-shortcuts.mu.html#L1833'>move-to-end-of-line</a> editor
<span id="L1815" class="LineNr">1815 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
<span id="L1816" class="LineNr">1816 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L1817" class="LineNr">1817 </span>   <span class="muControl"> return</span><span class="Constant"> false/don't-render</span>
<span id="L1818" class="LineNr">1818 </span>  <span class="Delimiter">}</span>
<span id="L1819" class="LineNr">1819 </span>]
<span id="L1820" class="LineNr">1820 </span>
<span id="L1821" class="LineNr">1821 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L199'>&lt;handle-special-key&gt;</a></span> [
<span id="L1822" class="LineNr">1822 </span>  <span class="Delimiter">{</span>
<span id="L1823" class="LineNr">1823 </span>    move-to-end-of-line?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65520/end</span>
<span id="L1824" class="LineNr">1824 </span>    <span class="muControl">break-unless</span> move-to-end-of-line?
<span id="L1825" class="LineNr">1825 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L1826" class="LineNr">1826 </span>    <a href='003-shortcuts.mu.html#L1833'>move-to-end-of-line</a> editor
<span id="L1827" class="LineNr">1827 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
<span id="L1828" class="LineNr">1828 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L1829" class="LineNr">1829 </span>   <span class="muControl"> return</span><span class="Constant"> false/don't-render</span>
<span id="L1830" class="LineNr">1830 </span>  <span class="Delimiter">}</span>
<span id="L1831" class="LineNr">1831 </span>]
<span id="L1832" class="LineNr">1832 </span>
<span id="L1833" class="LineNr">1833 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L1833'>move-to-end-of-line</a> editor:&amp;:editor<span class="muRecipe"> -&gt; </span>editor:&amp;:editor [
<span id="L1834" class="LineNr">1834 </span>  <span class="Constant">local-scope</span>
<span id="L1835" class="LineNr">1835 </span>  <span class="Constant">load-inputs</span>
<span id="L1836" class="LineNr">1836 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L1837" class="LineNr">1837 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L1838" class="LineNr">1838 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L1839" class="LineNr">1839 </span>  <span class="Comment"># while not at end of line, move</span>
<span id="L1840" class="LineNr">1840 </span>  <span class="Delimiter">{</span>
<span id="L1841" class="LineNr">1841 </span>    <a href='../065duplex_list.mu.html#L31'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-cursor
<span id="L1842" class="LineNr">1842 </span>    <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L31'>next</a>  <span class="Comment"># end of text</span>
<span id="L1843" class="LineNr">1843 </span>    nextc:char <span class="Special">&lt;-</span> get *next, <span class="Constant">value:offset</span>
<span id="L1844" class="LineNr">1844 </span>    at-end-of-line?:bool <span class="Special">&lt;-</span> equal nextc, <span class="Constant">10/newline</span>
<span id="L1845" class="LineNr">1845 </span>    <span class="muControl">break-if</span> at-end-of-line?
<span id="L1846" class="LineNr">1846 </span>    cursor-column <span class="Special">&lt;-</span> add cursor-column,<span class="Constant"> 1</span>
<span id="L1847" class="LineNr">1847 </span>    at-right?:bool <span class="Special">&lt;-</span> equal cursor-column, right
<span id="L1848" class="LineNr">1848 </span>    <span class="muControl">break-if</span> at-right?
<span id="L1849" class="LineNr">1849 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L1850" class="LineNr">1850 </span>    before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L31'>next</a>
<span id="L1851" class="LineNr">1851 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L1852" class="LineNr">1852 </span>   <span class="muControl"> loop</span>
<span id="L1853" class="LineNr">1853 </span>  <span class="Delimiter">}</span>
<span id="L1854" class="LineNr">1854 </span>]
<span id="L1855" class="LineNr">1855 </span>
<span id="L1856" class="LineNr">1856 </span><span class="muScenario">scenario</span> editor-moves-to-end-of-line-with-ctrl-e-2 [
<span id="L1857" class="LineNr">1857 </span>  <span class="Constant">local-scope</span>
<span id="L1858" class="LineNr">1858 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1859" class="LineNr">1859 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L1860" class="LineNr">1860 </span><span class="Constant">456]</span>
<span id="L1861" class="LineNr">1861 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1862" class="LineNr">1862 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1863" class="LineNr">1863 </span>  $clear-trace
<span id="L1864" class="LineNr">1864 </span>  <span class="Comment"># start on second line (no newline after), press ctrl-e</span>
<span id="L1865" class="LineNr">1865 </span>  assume-console [
<span id="L1866" class="LineNr">1866 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
<span id="L1867" class="LineNr">1867 </span>    press ctrl-e
<span id="L1868" class="LineNr">1868 </span>  ]
<span id="L1869" class="LineNr">1869 </span>  run [
<span id="L1870" class="LineNr">1870 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1871" class="LineNr">1871 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1872" class="LineNr">1872 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1873" class="LineNr">1873 </span>  ]
<span id="L1874" class="LineNr">1874 </span>  <span class="Comment"># cursor moves to end of line</span>
<span id="L1875" class="LineNr">1875 </span>  memory-should-contain [
<span id="L1876" class="LineNr">1876 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1877" class="LineNr">1877 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L1878" class="LineNr">1878 </span>  ]
<span id="L1879" class="LineNr">1879 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1880" class="LineNr">1880 </span>]
<span id="L1881" class="LineNr">1881 </span>
<span id="L1882" class="LineNr">1882 </span><span class="muScenario">scenario</span> editor-moves-to-end-of-line-with-end [
<span id="L1883" class="LineNr">1883 </span>  <span class="Constant">local-scope</span>
<span id="L1884" class="LineNr">1884 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1885" class="LineNr">1885 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L1886" class="LineNr">1886 </span><span class="Constant">456]</span>
<span id="L1887" class="LineNr">1887 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1888" class="LineNr">1888 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1889" class="LineNr">1889 </span>  $clear-trace
<span id="L1890" class="LineNr">1890 </span>  <span class="Comment"># start on first line, press 'end'</span>
<span id="L1891" class="LineNr">1891 </span>  assume-console [
<span id="L1892" class="LineNr">1892 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
<span id="L1893" class="LineNr">1893 </span>    press end
<span id="L1894" class="LineNr">1894 </span>  ]
<span id="L1895" class="LineNr">1895 </span>  run [
<span id="L1896" class="LineNr">1896 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1897" class="LineNr">1897 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1898" class="LineNr">1898 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1899" class="LineNr">1899 </span>  ]
<span id="L1900" class="LineNr">1900 </span>  <span class="Comment"># cursor moves to end of line</span>
<span id="L1901" class="LineNr">1901 </span>  memory-should-contain [
<span id="L1902" class="LineNr">1902 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1903" class="LineNr">1903 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L1904" class="LineNr">1904 </span>  ]
<span id="L1905" class="LineNr">1905 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1906" class="LineNr">1906 </span>]
<span id="L1907" class="LineNr">1907 </span>
<span id="L1908" class="LineNr">1908 </span><span class="muScenario">scenario</span> editor-moves-to-end-of-line-with-end-2 [
<span id="L1909" class="LineNr">1909 </span>  <span class="Constant">local-scope</span>
<span id="L1910" class="LineNr">1910 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1911" class="LineNr">1911 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L1912" class="LineNr">1912 </span><span class="Constant">456]</span>
<span id="L1913" class="LineNr">1913 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1914" class="LineNr">1914 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1915" class="LineNr">1915 </span>  $clear-trace
<span id="L1916" class="LineNr">1916 </span>  <span class="Comment"># start on second line (no newline after), press 'end'</span>
<span id="L1917" class="LineNr">1917 </span>  assume-console [
<span id="L1918" class="LineNr">1918 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
<span id="L1919" class="LineNr">1919 </span>    press end
<span id="L1920" class="LineNr">1920 </span>  ]
<span id="L1921" class="LineNr">1921 </span>  run [
<span id="L1922" class="LineNr">1922 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1923" class="LineNr">1923 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1924" class="LineNr">1924 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1925" class="LineNr">1925 </span>  ]
<span id="L1926" class="LineNr">1926 </span>  <span class="Comment"># cursor moves to end of line</span>
<span id="L1927" class="LineNr">1927 </span>  memory-should-contain [
<span id="L1928" class="LineNr">1928 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1929" class="LineNr">1929 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L1930" class="LineNr">1930 </span>  ]
<span id="L1931" class="LineNr">1931 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1932" class="LineNr">1932 </span>]
<span id="L1933" class="LineNr">1933 </span>
<span id="L1934" class="LineNr">1934 </span><span class="muScenario">scenario</span> editor-moves-to-end-of-wrapped-line [
<span id="L1935" class="LineNr">1935 </span>  <span class="Constant">local-scope</span>
<span id="L1936" class="LineNr">1936 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1937" class="LineNr">1937 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123456</span>
<span id="L1938" class="LineNr">1938 </span><span class="Constant">789]</span>
<span id="L1939" class="LineNr">1939 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L1940" class="LineNr">1940 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1941" class="LineNr">1941 </span>  $clear-trace
<span id="L1942" class="LineNr">1942 </span>  <span class="Comment"># start on first line, press 'end'</span>
<span id="L1943" class="LineNr">1943 </span>  assume-console [
<span id="L1944" class="LineNr">1944 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
<span id="L1945" class="LineNr">1945 </span>    press end
<span id="L1946" class="LineNr">1946 </span>  ]
<span id="L1947" class="LineNr">1947 </span>  run [
<span id="L1948" class="LineNr">1948 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1949" class="LineNr">1949 </span>    10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1950" class="LineNr">1950 </span>    11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1951" class="LineNr">1951 </span>  ]
<span id="L1952" class="LineNr">1952 </span>  <span class="Comment"># cursor moves to end of line</span>
<span id="L1953" class="LineNr">1953 </span>  memory-should-contain [
<span id="L1954" class="LineNr">1954 </span>   <span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1955" class="LineNr">1955 </span>   <span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L1956" class="LineNr">1956 </span>  ]
<span id="L1957" class="LineNr">1957 </span>  <span class="Comment"># no prints</span>
<span id="L1958" class="LineNr">1958 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1959" class="LineNr">1959 </span>  <span class="Comment"># before-cursor is also consistent</span>
<span id="L1960" class="LineNr">1960 </span>  assume-console [
<span id="L1961" class="LineNr">1961 </span>    type <span class="Constant">[a]</span>
<span id="L1962" class="LineNr">1962 </span>  ]
<span id="L1963" class="LineNr">1963 </span>  run [
<span id="L1964" class="LineNr">1964 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1965" class="LineNr">1965 </span>  ]
<span id="L1966" class="LineNr">1966 </span>  screen-should-contain [
<span id="L1967" class="LineNr">1967 </span>   <span class="Constant"> .          .</span>
<span id="L1968" class="LineNr">1968 </span>   <span class="Constant"> .123a↩     .</span>
<span id="L1969" class="LineNr">1969 </span>   <span class="Constant"> .456       .</span>
<span id="L1970" class="LineNr">1970 </span>   <span class="Constant"> .789       .</span>
<span id="L1971" class="LineNr">1971 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L1972" class="LineNr">1972 </span>  ]
<span id="L1973" class="LineNr">1973 </span>]
<span id="L1974" class="LineNr">1974 </span>
<span id="L1975" class="LineNr">1975 </span><span class="Comment"># ctrl-u - delete text from start of line until (but not at) cursor</span>
<span id="L1976" class="LineNr">1976 </span>
<span id="L1977" class="LineNr">1977 </span><span class="muScenario">scenario</span> editor-deletes-to-start-of-line-with-ctrl-u [
<span id="L1978" class="LineNr">1978 </span>  <span class="Constant">local-scope</span>
<span id="L1979" class="LineNr">1979 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1980" class="LineNr">1980 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L1981" class="LineNr">1981 </span><span class="Constant">456]</span>
<span id="L1982" class="LineNr">1982 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1983" class="LineNr">1983 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1984" class="LineNr">1984 </span>  $clear-trace
<span id="L1985" class="LineNr">1985 </span>  <span class="Comment"># start on second line, press ctrl-u</span>
<span id="L1986" class="LineNr">1986 </span>  assume-console [
<span id="L1987" class="LineNr">1987 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 2</span>
<span id="L1988" class="LineNr">1988 </span>    press ctrl-u
<span id="L1989" class="LineNr">1989 </span>  ]
<span id="L1990" class="LineNr">1990 </span>  run [
<span id="L1991" class="LineNr">1991 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1992" class="LineNr">1992 </span>  ]
<span id="L1993" class="LineNr">1993 </span>  <span class="Comment"># cursor deletes to start of line</span>
<span id="L1994" class="LineNr">1994 </span>  screen-should-contain [
<span id="L1995" class="LineNr">1995 </span>   <span class="Constant"> .          .</span>
<span id="L1996" class="LineNr">1996 </span>   <span class="Constant"> .123       .</span>
<span id="L1997" class="LineNr">1997 </span>   <span class="Constant"> .6         .</span>
<span id="L1998" class="LineNr">1998 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1999" class="LineNr">1999 </span>   <span class="Constant"> .          .</span>
<span id="L2000" class="LineNr">2000 </span>  ]
<span id="L2001" class="LineNr">2001 </span>  check-trace-count-for-label<span class="Constant"> 10</span>, <span class="Constant">[print-character]</span>
<span id="L2002" class="LineNr">2002 </span>]
<span id="L2003" class="LineNr">2003 </span>
<span id="L2004" class="LineNr">2004 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L2005" class="LineNr">2005 </span>  <span class="Delimiter">{</span>
<span id="L2006" class="LineNr">2006 </span>    delete-to-start-of-line?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">21/ctrl-u</span>
<span id="L2007" class="LineNr">2007 </span>    <span class="muControl">break-unless</span> delete-to-start-of-line?
<span id="L2008" class="LineNr">2008 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L2008'>&lt;begin-delete-to-start-of-line&gt;</a></span>
<span id="L2009" class="LineNr">2009 </span>    deleted-cells:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2051'>delete-to-start-of-line</a> editor
<span id="L2010" class="LineNr">2010 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L2010'>&lt;end-delete-to-start-of-line&gt;</a></span>
<span id="L2011" class="LineNr">2011 </span>    go-render?:bool <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2016'>minimal-render-for-ctrl-u</a> <a href='../081print.mu.html#L16'>screen</a>, editor, deleted-cells
<span id="L2012" class="LineNr">2012 </span>   <span class="muControl"> return</span>
<span id="L2013" class="LineNr">2013 </span>  <span class="Delimiter">}</span>
<span id="L2014" class="LineNr">2014 </span>]
<span id="L2015" class="LineNr">2015 </span>
<span id="L2016" class="LineNr">2016 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L2016'>minimal-render-for-ctrl-u</a> <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a>, editor:&amp;:editor, deleted-cells:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char<span class="muRecipe"> -&gt; </span>go-render?:bool, <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a> [
<span id="L2017" class="LineNr">2017 </span>  <span class="Constant">local-scope</span>
<span id="L2018" class="LineNr">2018 </span>  <span class="Constant">load-inputs</span>
<span id="L2019" class="LineNr">2019 </span>  curr-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L2020" class="LineNr">2020 </span>  <span class="Comment"># accumulate the current line as text and render it</span>
<span id="L2021" class="LineNr">2021 </span>  buf:&amp;:<a href='../061text.mu.html#L120'>buffer</a>:char <span class="Special">&lt;-</span> <a href='../061text.mu.html#L125'>new-buffer</a><span class="Constant"> 30</span>  <span class="Comment"># accumulator for the text we need to render</span>
<span id="L2022" class="LineNr">2022 </span>  curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L2023" class="LineNr">2023 </span>  i:num <span class="Special">&lt;-</span> copy curr-column
<span id="L2024" class="LineNr">2024 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L2025" class="LineNr">2025 </span>  <span class="Delimiter">{</span>
<span id="L2026" class="LineNr">2026 </span>    <span class="Comment"># if we have a wrapped line, give up and render the whole screen</span>
<span id="L2027" class="LineNr">2027 </span>    wrap?:bool <span class="Special">&lt;-</span> greater-or-equal i, right
<span id="L2028" class="LineNr">2028 </span>    <span class="muControl">return-if</span> wrap?,<span class="Constant"> true/go-render</span>
<span id="L2029" class="LineNr">2029 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> curr
<span id="L2030" class="LineNr">2030 </span>    <span class="muControl">break-unless</span> curr
<span id="L2031" class="LineNr">2031 </span>    c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
<span id="L2032" class="LineNr">2032 </span>    b:bool <span class="Special">&lt;-</span> equal c,<span class="Constant"> 10</span>
<span id="L2033" class="LineNr">2033 </span>    <span class="muControl">break-if</span> b
<span id="L2034" class="LineNr">2034 </span>    buf <span class="Special">&lt;-</span> append buf, c
<span id="L2035" class="LineNr">2035 </span>    i <span class="Special">&lt;-</span> add i,<span class="Constant"> 1</span>
<span id="L2036" class="LineNr">2036 </span>   <span class="muControl"> loop</span>
<span id="L2037" class="LineNr">2037 </span>  <span class="Delimiter">}</span>
<span id="L2038" class="LineNr">2038 </span>  <span class="Comment"># if the line used to be wrapped, give up and render the whole screen</span>
<span id="L2039" class="LineNr">2039 </span>  num-deleted-cells:num <span class="Special">&lt;-</span> length deleted-cells
<span id="L2040" class="LineNr">2040 </span>  old-row-len:num <span class="Special">&lt;-</span> add i, num-deleted-cells
<span id="L2041" class="LineNr">2041 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L2042" class="LineNr">2042 </span>  end:num <span class="Special">&lt;-</span> subtract right, left
<span id="L2043" class="LineNr">2043 </span>  wrap?:bool <span class="Special">&lt;-</span> greater-or-equal old-row-len, end
<span id="L2044" class="LineNr">2044 </span>  <span class="muControl">return-if</span> wrap?,<span class="Constant"> true/go-render</span>
<span id="L2045" class="LineNr">2045 </span>  curr-line:text <span class="Special">&lt;-</span> <a href='../061text.mu.html#L338'>buffer-to-array</a> buf
<span id="L2046" class="LineNr">2046 </span>  curr-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L2047" class="LineNr">2047 </span>  <a href='003-shortcuts.mu.html#L2107'>render-code</a> <a href='../081print.mu.html#L16'>screen</a>, curr-line, curr-column, right, curr-row
<span id="L2048" class="LineNr">2048 </span> <span class="muControl"> return</span><span class="Constant"> false/dont-render</span>
<span id="L2049" class="LineNr">2049 </span>]
<span id="L2050" class="LineNr">2050 </span>
<span id="L2051" class="LineNr">2051 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L2051'>delete-to-start-of-line</a> editor:&amp;:editor<span class="muRecipe"> -&gt; </span>result:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char, editor:&amp;:editor [
<span id="L2052" class="LineNr">2052 </span>  <span class="Constant">local-scope</span>
<span id="L2053" class="LineNr">2053 </span>  <span class="Constant">load-inputs</span>
<span id="L2054" class="LineNr">2054 </span>  <span class="Comment"># compute range to delete</span>
<span id="L2055" class="LineNr">2055 </span>  init:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
<span id="L2056" class="LineNr">2056 </span>  top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L2057" class="LineNr">2057 </span>  update-top-of-screen?:bool <span class="Special">&lt;-</span> copy<span class="Constant"> false</span>
<span id="L2058" class="LineNr">2058 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L2059" class="LineNr">2059 </span>  start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy before-cursor
<span id="L2060" class="LineNr">2060 </span>  end:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-cursor
<span id="L2061" class="LineNr">2061 </span>  <span class="Delimiter">{</span>
<span id="L2062" class="LineNr">2062 </span>    at-start-of-text?:bool <span class="Special">&lt;-</span> equal start, init
<span id="L2063" class="LineNr">2063 </span>    <span class="muControl">break-if</span> at-start-of-text?
<span id="L2064" class="LineNr">2064 </span>    curr:char <span class="Special">&lt;-</span> get *start, <span class="Constant">value:offset</span>
<span id="L2065" class="LineNr">2065 </span>    at-start-of-line?:bool <span class="Special">&lt;-</span> equal curr, <span class="Constant">10/newline</span>
<span id="L2066" class="LineNr">2066 </span>    <span class="muControl">break-if</span> at-start-of-line?
<span id="L2067" class="LineNr">2067 </span>    <span class="Comment"># if we went past top-of-screen, make a note to update it as well</span>
<span id="L2068" class="LineNr">2068 </span>    at-top-of-screen?:bool <span class="Special">&lt;-</span> equal start, top-of-screen
<span id="L2069" class="LineNr">2069 </span>    update-top-of-screen?:bool <span class="Special">&lt;-</span> or update-top-of-screen?, at-top-of-screen?
<span id="L2070" class="LineNr">2070 </span>    start <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L38'>prev</a> start
<span id="L2071" class="LineNr">2071 </span>    assert start, <span class="Constant">[delete-to-start-of-line tried to move before start of text]</span>
<span id="L2072" class="LineNr">2072 </span>   <span class="muControl"> loop</span>
<span id="L2073" class="LineNr">2073 </span>  <span class="Delimiter">}</span>
<span id="L2074" class="LineNr">2074 </span>  <span class="Comment"># snip it out</span>
<span id="L2075" class="LineNr">2075 </span>  result:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> start
<span id="L2076" class="LineNr">2076 </span>  <a href='../065duplex_list.mu.html#L391'>remove-between</a> start, end
<span id="L2077" class="LineNr">2077 </span>  <span class="Comment"># update top-of-screen if it's just been invalidated</span>
<span id="L2078" class="LineNr">2078 </span>  <span class="Delimiter">{</span>
<span id="L2079" class="LineNr">2079 </span>    <span class="muControl">break-unless</span> update-top-of-screen?
<span id="L2080" class="LineNr">2080 </span>    put *editor, <span class="Constant">top-of-screen:offset</span>, start
<span id="L2081" class="LineNr">2081 </span>  <span class="Delimiter">}</span>
<span id="L2082" class="LineNr">2082 </span>  <span class="Comment"># adjust cursor</span>
<span id="L2083" class="LineNr">2083 </span>  before-cursor <span class="Special">&lt;-</span> copy start
<span id="L2084" class="LineNr">2084 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L2085" class="LineNr">2085 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L2086" class="LineNr">2086 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, left
<span id="L2087" class="LineNr">2087 </span>  <span class="Comment"># if the line wrapped before, we may need to adjust cursor-row as well</span>
<span id="L2088" class="LineNr">2088 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L2089" class="LineNr">2089 </span>  width:num <span class="Special">&lt;-</span> subtract right, left
<span id="L2090" class="LineNr">2090 </span>  num-deleted:num <span class="Special">&lt;-</span> length result
<span id="L2091" class="LineNr">2091 </span>  cursor-row-adjustment:num <span class="Special">&lt;-</span> divide-with-remainder num-deleted, width
<span id="L2092" class="LineNr">2092 </span>  <span class="muControl">return-unless</span> cursor-row-adjustment
<span id="L2093" class="LineNr">2093 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L2094" class="LineNr">2094 </span>  cursor-row-in-editor:num <span class="Special">&lt;-</span> subtract cursor-row,<span class="Constant"> 1</span>  <span class="Comment"># ignore menubar</span>
<span id="L2095" class="LineNr">2095 </span>  at-top?:bool <span class="Special">&lt;-</span> lesser-or-equal cursor-row-in-editor, cursor-row-adjustment
<span id="L2096" class="LineNr">2096 </span>  <span class="Delimiter">{</span>
<span id="L2097" class="LineNr">2097 </span>    <span class="muControl">break-unless</span> at-top?
<span id="L2098" class="LineNr">2098 </span>    cursor-row <span class="Special">&lt;-</span> copy<span class="Constant"> 1</span>  <span class="Comment"># top of editor, below menubar</span>
<span id="L2099" class="LineNr">2099 </span>  <span class="Delimiter">}</span>
<span id="L2100" class="LineNr">2100 </span>  <span class="Delimiter">{</span>
<span id="L2101" class="LineNr">2101 </span>    <span class="muControl">break-if</span> at-top?
<span id="L2102" class="LineNr">2102 </span>    cursor-row <span class="Special">&lt;-</span> subtract cursor-row, cursor-row-adjustment
<span id="L2103" class="LineNr">2103 </span>  <span class="Delimiter">}</span>
<span id="L2104" class="LineNr">2104 </span>  put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
<span id="L2105" class="LineNr">2105 </span>]
<span id="L2106" class="LineNr">2106 </span>
<span id="L2107" class="LineNr">2107 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L2107'>render-code</a> <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a>, s:text, left:num, right:num, row:num<span class="muRecipe"> -&gt; </span>row:num, <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a> [
<span id="L2108" class="LineNr">2108 </span>  <span class="Constant">local-scope</span>
<span id="L2109" class="LineNr">2109 </span>  <span class="Constant">load-inputs</span>
<span id="L2110" class="LineNr">2110 </span>  <span class="muControl">return-unless</span> s
<span id="L2111" class="LineNr">2111 </span>  color:num <span class="Special">&lt;-</span> copy <span class="Constant">7/white</span>
<span id="L2112" class="LineNr">2112 </span>  column:num <span class="Special">&lt;-</span> copy left
<span id="L2113" class="LineNr">2113 </span>  <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> move-cursor <a href='../081print.mu.html#L16'>screen</a>, row, column
<span id="L2114" class="LineNr">2114 </span>  <a href='../081print.mu.html#L782'>screen-height</a>:num <span class="Special">&lt;-</span> <a href='../081print.mu.html#L782'>screen-height</a> <a href='../081print.mu.html#L16'>screen</a>
<span id="L2115" class="LineNr">2115 </span>  i:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
<span id="L2116" class="LineNr">2116 </span>  len:num <span class="Special">&lt;-</span> length *s
<span id="L2117" class="LineNr">2117 </span>  <span class="Delimiter">{</span>
<span id="L2118" class="LineNr">2118 </span><span class="Constant">    +next-character</span>
<span id="L2119" class="LineNr">2119 </span>    done?:bool <span class="Special">&lt;-</span> greater-or-equal i, len
<span id="L2120" class="LineNr">2120 </span>    <span class="muControl">break-if</span> done?
<span id="L2121" class="LineNr">2121 </span>    done? <span class="Special">&lt;-</span> greater-or-equal row, <a href='../081print.mu.html#L782'>screen-height</a>
<span id="L2122" class="LineNr">2122 </span>    <span class="muControl">break-if</span> done?
<span id="L2123" class="LineNr">2123 </span>    c:char <span class="Special">&lt;-</span> index *s, i
<span id="L2124" class="LineNr">2124 </span><span class="Constant">    &lt;character-c-received&gt;</span>
<span id="L2125" class="LineNr">2125 </span>    <span class="Delimiter">{</span>
<span id="L2126" class="LineNr">2126 </span>      <span class="Comment"># newline? move to left rather than 0</span>
<span id="L2127" class="LineNr">2127 </span>      newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
<span id="L2128" class="LineNr">2128 </span>      <span class="muControl">break-unless</span> newline?
<span id="L2129" class="LineNr">2129 </span>      <span class="Comment"># clear rest of line in this window</span>
<span id="L2130" class="LineNr">2130 </span>      <span class="Delimiter">{</span>
<span id="L2131" class="LineNr">2131 </span>        done?:bool <span class="Special">&lt;-</span> greater-than column, right
<span id="L2132" class="LineNr">2132 </span>        <span class="muControl">break-if</span> done?
<span id="L2133" class="LineNr">2133 </span>        space:char <span class="Special">&lt;-</span> copy <span class="Constant">32/space</span>
<span id="L2134" class="LineNr">2134 </span>        print <a href='../081print.mu.html#L16'>screen</a>, space
<span id="L2135" class="LineNr">2135 </span>        column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
<span id="L2136" class="LineNr">2136 </span>       <span class="muControl"> loop</span>
<span id="L2137" class="LineNr">2137 </span>      <span class="Delimiter">}</span>
<span id="L2138" class="LineNr">2138 </span>      row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
<span id="L2139" class="LineNr">2139 </span>      column <span class="Special">&lt;-</span> copy left
<span id="L2140" class="LineNr">2140 </span>      <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> move-cursor <a href='../081print.mu.html#L16'>screen</a>, row, column
<span id="L2141" class="LineNr">2141 </span>      i <span class="Special">&lt;-</span> add i,<span class="Constant"> 1</span>
<span id="L2142" class="LineNr">2142 </span>     <span class="muControl"> loop</span> <span class="Constant">+next-character</span>
<span id="L2143" class="LineNr">2143 </span>    <span class="Delimiter">}</span>
<span id="L2144" class="LineNr">2144 </span>    <span class="Delimiter">{</span>
<span id="L2145" class="LineNr">2145 </span>      <span class="Comment"># at right? wrap.</span>
<span id="L2146" class="LineNr">2146 </span>      at-right?:bool <span class="Special">&lt;-</span> equal column, right
<span id="L2147" class="LineNr">2147 </span>      <span class="muControl">break-unless</span> at-right?
<span id="L2148" class="LineNr">2148 </span>      <span class="Comment"># print wrap icon</span>
<span id="L2149" class="LineNr">2149 </span>      wrap-icon:char <span class="Special">&lt;-</span> copy <span class="Constant">8617/loop-back-to-left</span>
<span id="L2150" class="LineNr">2150 </span>      print <a href='../081print.mu.html#L16'>screen</a>, wrap-icon, <span class="Constant">245/grey</span>
<span id="L2151" class="LineNr">2151 </span>      column <span class="Special">&lt;-</span> copy left
<span id="L2152" class="LineNr">2152 </span>      row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
<span id="L2153" class="LineNr">2153 </span>      <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> move-cursor <a href='../081print.mu.html#L16'>screen</a>, row, column
<span id="L2154" class="LineNr">2154 </span>      <span class="Comment"># don't increment i</span>
<span id="L2155" class="LineNr">2155 </span>     <span class="muControl"> loop</span> <span class="Constant">+next-character</span>
<span id="L2156" class="LineNr">2156 </span>    <span class="Delimiter">}</span>
<span id="L2157" class="LineNr">2157 </span>    i <span class="Special">&lt;-</span> add i,<span class="Constant"> 1</span>
<span id="L2158" class="LineNr">2158 </span>    print <a href='../081print.mu.html#L16'>screen</a>, c, color
<span id="L2159" class="LineNr">2159 </span>    column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
<span id="L2160" class="LineNr">2160 </span>   <span class="muControl"> loop</span>
<span id="L2161" class="LineNr">2161 </span>  <span class="Delimiter">}</span>
<span id="L2162" class="LineNr">2162 </span>  was-at-left?:bool <span class="Special">&lt;-</span> equal column, left
<span id="L2163" class="LineNr">2163 </span>  <a href='../081print.mu.html#L553'>clear-line-until</a> <a href='../081print.mu.html#L16'>screen</a>, right
<span id="L2164" class="LineNr">2164 </span>  <span class="Delimiter">{</span>
<span id="L2165" class="LineNr">2165 </span>    <span class="muControl">break-if</span> was-at-left?
<span id="L2166" class="LineNr">2166 </span>    row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
<span id="L2167" class="LineNr">2167 </span>  <span class="Delimiter">}</span>
<span id="L2168" class="LineNr">2168 </span>  move-cursor <a href='../081print.mu.html#L16'>screen</a>, row, left
<span id="L2169" class="LineNr">2169 </span>]
<span id="L2170" class="LineNr">2170 </span>
<span id="L2171" class="LineNr">2171 </span><span class="muScenario">scenario</span> editor-deletes-to-start-of-line-with-ctrl-u-2 [
<span id="L2172" class="LineNr">2172 </span>  <span class="Constant">local-scope</span>
<span id="L2173" class="LineNr">2173 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L2174" class="LineNr">2174 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L2175" class="LineNr">2175 </span><span class="Constant">456]</span>
<span id="L2176" class="LineNr">2176 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L2177" class="LineNr">2177 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2178" class="LineNr">2178 </span>  $clear-trace
<span id="L2179" class="LineNr">2179 </span>  <span class="Comment"># start on first line (no newline before), press ctrl-u</span>
<span id="L2180" class="LineNr">2180 </span>  assume-console [
<span id="L2181" class="LineNr">2181 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 2</span>
<span id="L2182" class="LineNr">2182 </span>    press ctrl-u
<span id="L2183" class="LineNr">2183 </span>  ]
<span id="L2184" class="LineNr">2184 </span>  run [
<span id="L2185" class="LineNr">2185 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2186" class="LineNr">2186 </span>  ]
<span id="L2187" class="LineNr">2187 </span>  <span class="Comment"># cursor deletes to start of line</span>
<span id="L2188" class="LineNr">2188 </span>  screen-should-contain [
<span id="L2189" class="LineNr">2189 </span>   <span class="Constant"> .          .</span>
<span id="L2190" class="LineNr">2190 </span>   <span class="Constant"> .3         .</span>
<span id="L2191" class="LineNr">2191 </span>   <span class="Constant"> .456       .</span>
<span id="L2192" class="LineNr">2192 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2193" class="LineNr">2193 </span>   <span class="Constant"> .          .</span>
<span id="L2194" class="LineNr">2194 </span>  ]
<span id="L2195" class="LineNr">2195 </span>  check-trace-count-for-label<span class="Constant"> 10</span>, <span class="Constant">[print-character]</span>
<span id="L2196" class="LineNr">2196 </span>]
<span id="L2197" class="LineNr">2197 </span>
<span id="L2198" class="LineNr">2198 </span><span class="muScenario">scenario</span> editor-deletes-to-start-of-line-with-ctrl-u-3 [
<span id="L2199" class="LineNr">2199 </span>  <span class="Constant">local-scope</span>
<span id="L2200" class="LineNr">2200 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L2201" class="LineNr">2201 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L2202" class="LineNr">2202 </span><span class="Constant">456]</span>
<span id="L2203" class="LineNr">2203 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L2204" class="LineNr">2204 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2205" class="LineNr">2205 </span>  $clear-trace
<span id="L2206" class="LineNr">2206 </span>  <span class="Comment"># start past end of line, press ctrl-u</span>
<span id="L2207" class="LineNr">2207 </span>  assume-console [
<span id="L2208" class="LineNr">2208 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
<span id="L2209" class="LineNr">2209 </span>    press ctrl-u
<span id="L2210" class="LineNr">2210 </span>  ]
<span id="L2211" class="LineNr">2211 </span>  run [
<span id="L2212" class="LineNr">2212 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2213" class="LineNr">2213 </span>  ]
<span id="L2214" class="LineNr">2214 </span>  <span class="Comment"># cursor deletes to start of line</span>
<span id="L2215" class="LineNr">2215 </span>  screen-should-contain [
<span id="L2216" class="LineNr">2216 </span>   <span class="Constant"> .          .</span>
<span id="L2217" class="LineNr">2217 </span>   <span class="Constant"> .          .</span>
<span id="L2218" class="LineNr">2218 </span>   <span class="Constant"> .456       .</span>
<span id="L2219" class="LineNr">2219 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2220" class="LineNr">2220 </span>   <span class="Constant"> .          .</span>
<span id="L2221" class="LineNr">2221 </span>  ]
<span id="L2222" class="LineNr">2222 </span>  check-trace-count-for-label<span class="Constant"> 10</span>, <span class="Constant">[print-character]</span>
<span id="L2223" class="LineNr">2223 </span>]
<span id="L2224" class="LineNr">2224 </span>
<span id="L2225" class="LineNr">2225 </span><span class="muScenario">scenario</span> editor-deletes-to-start-of-final-line-with-ctrl-u [
<span id="L2226" class="LineNr">2226 </span>  <span class="Constant">local-scope</span>
<span id="L2227" class="LineNr">2227 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L2228" class="LineNr">2228 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L2229" class="LineNr">2229 </span><span class="Constant">456]</span>
<span id="L2230" class="LineNr">2230 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L2231" class="LineNr">2231 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2232" class="LineNr">2232 </span>  $clear-trace
<span id="L2233" class="LineNr">2233 </span>  <span class="Comment"># start past end of final line, press ctrl-u</span>
<span id="L2234" class="LineNr">2234 </span>  assume-console [
<span id="L2235" class="LineNr">2235 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
<span id="L2236" class="LineNr">2236 </span>    press ctrl-u
<span id="L2237" class="LineNr">2237 </span>  ]
<span id="L2238" class="LineNr">2238 </span>  run [
<span id="L2239" class="LineNr">2239 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2240" class="LineNr">2240 </span>  ]
<span id="L2241" class="LineNr">2241 </span>  <span class="Comment"># cursor deletes to start of line</span>
<span id="L2242" class="LineNr">2242 </span>  screen-should-contain [
<span id="L2243" class="LineNr">2243 </span>   <span class="Constant"> .          .</span>
<span id="L2244" class="LineNr">2244 </span>   <span class="Constant"> .123       .</span>
<span id="L2245" class="LineNr">2245 </span>   <span class="Constant"> .          .</span>
<span id="L2246" class="LineNr">2246 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2247" class="LineNr">2247 </span>   <span class="Constant"> .          .</span>
<span id="L2248" class="LineNr">2248 </span>  ]
<span id="L2249" class="LineNr">2249 </span>  check-trace-count-for-label<span class="Constant"> 10</span>, <span class="Constant">[print-character]</span>
<span id="L2250" class="LineNr">2250 </span>]
<span id="L2251" class="LineNr">2251 </span>
<span id="L2252" class="LineNr">2252 </span><span class="muScenario">scenario</span> editor-deletes-to-start-of-wrapped-line-with-ctrl-u [
<span id="L2253" class="LineNr">2253 </span>  <span class="Constant">local-scope</span>
<span id="L2254" class="LineNr">2254 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">10/height</span>
<span id="L2255" class="LineNr">2255 </span>  <span class="Comment"># first line starts out wrapping</span>
<span id="L2256" class="LineNr">2256 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123456</span>
<span id="L2257" class="LineNr">2257 </span><span class="Constant">789]</span>
<span id="L2258" class="LineNr">2258 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L2259" class="LineNr">2259 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2260" class="LineNr">2260 </span>  screen-should-contain [
<span id="L2261" class="LineNr">2261 </span>   <span class="Constant"> .          .</span>
<span id="L2262" class="LineNr">2262 </span>   <span class="Constant"> .1234↩     .</span>
<span id="L2263" class="LineNr">2263 </span>   <span class="Constant"> .56        .</span>
<span id="L2264" class="LineNr">2264 </span>   <span class="Constant"> .789       .</span>
<span id="L2265" class="LineNr">2265 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2266" class="LineNr">2266 </span>   <span class="Constant"> .          .</span>
<span id="L2267" class="LineNr">2267 </span>  ]
<span id="L2268" class="LineNr">2268 </span>  $clear-trace
<span id="L2269" class="LineNr">2269 </span>  <span class="Comment"># ctrl-u enough of the first line that it's no longer wrapping</span>
<span id="L2270" class="LineNr">2270 </span>  assume-console [
<span id="L2271" class="LineNr">2271 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
<span id="L2272" class="LineNr">2272 </span>    press ctrl-u
<span id="L2273" class="LineNr">2273 </span>  ]
<span id="L2274" class="LineNr">2274 </span>  run [
<span id="L2275" class="LineNr">2275 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2276" class="LineNr">2276 </span>  ]
<span id="L2277" class="LineNr">2277 </span>  <span class="Comment"># entire screen needs to be refreshed</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"> .456       .</span>
<span id="L2281" class="LineNr">2281 </span>   <span class="Constant"> .789       .</span>
<span id="L2282" class="LineNr">2282 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2283" class="LineNr">2283 </span>   <span class="Constant"> .          .</span>
<span id="L2284" class="LineNr">2284 </span>  ]
<span id="L2285" class="LineNr">2285 </span>  check-trace-count-for-label<span class="Constant"> 45</span>, <span class="Constant">[print-character]</span>
<span id="L2286" class="LineNr">2286 </span>]
<span id="L2287" class="LineNr">2287 </span>
<span id="L2288" class="LineNr">2288 </span><span class="Comment"># sometimes hitting ctrl-u needs to adjust the cursor row</span>
<span id="L2289" class="LineNr">2289 </span><span class="muScenario">scenario</span> editor-deletes-to-start-of-wrapped-line-with-ctrl-u-2 [
<span id="L2290" class="LineNr">2290 </span>  <span class="Constant">local-scope</span>
<span id="L2291" class="LineNr">2291 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">10/height</span>
<span id="L2292" class="LineNr">2292 </span>  <span class="Comment"># third line starts out wrapping</span>
<span id="L2293" class="LineNr">2293 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[1</span>
<span id="L2294" class="LineNr">2294 </span><span class="Constant">2</span>
<span id="L2295" class="LineNr">2295 </span><span class="Constant">345678</span>
<span id="L2296" class="LineNr">2296 </span><span class="Constant">9]</span>
<span id="L2297" class="LineNr">2297 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L2298" class="LineNr">2298 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2299" class="LineNr">2299 </span>  screen-should-contain [
<span id="L2300" class="LineNr">2300 </span>   <span class="Constant"> .          .</span>
<span id="L2301" class="LineNr">2301 </span>   <span class="Constant"> .1         .</span>
<span id="L2302" class="LineNr">2302 </span>   <span class="Constant"> .2         .</span>
<span id="L2303" class="LineNr">2303 </span>   <span class="Constant"> .3456↩     .</span>
<span id="L2304" class="LineNr">2304 </span>   <span class="Constant"> .78        .</span>
<span id="L2305" class="LineNr">2305 </span>   <span class="Constant"> .9         .</span>
<span id="L2306" class="LineNr">2306 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2307" class="LineNr">2307 </span>   <span class="Constant"> .          .</span>
<span id="L2308" class="LineNr">2308 </span>  ]
<span id="L2309" class="LineNr">2309 </span>  <span class="Comment"># position cursor on screen line after the wrap and hit ctrl-u</span>
<span id="L2310" class="LineNr">2310 </span>  assume-console [
<span id="L2311" class="LineNr">2311 </span>    left-click<span class="Constant"> 4</span>,<span class="Constant"> 1</span>  <span class="Comment"># on '8'</span>
<span id="L2312" class="LineNr">2312 </span>    press ctrl-u
<span id="L2313" class="LineNr">2313 </span>  ]
<span id="L2314" class="LineNr">2314 </span>  run [
<span id="L2315" class="LineNr">2315 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2316" class="LineNr">2316 </span>    10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L2317" class="LineNr">2317 </span>    11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L2318" class="LineNr">2318 </span>  ]
<span id="L2319" class="LineNr">2319 </span>  screen-should-contain [
<span id="L2320" class="LineNr">2320 </span>   <span class="Constant"> .          .</span>
<span id="L2321" class="LineNr">2321 </span>   <span class="Constant"> .1         .</span>
<span id="L2322" class="LineNr">2322 </span>   <span class="Constant"> .2         .</span>
<span id="L2323" class="LineNr">2323 </span>   <span class="Constant"> .8         .</span>
<span id="L2324" class="LineNr">2324 </span>   <span class="Constant"> .9         .</span>
<span id="L2325" class="LineNr">2325 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2326" class="LineNr">2326 </span>   <span class="Constant"> .          .</span>
<span id="L2327" class="LineNr">2327 </span>  ]
<span id="L2328" class="LineNr">2328 </span>  <span class="Comment"># cursor moves up one screen line</span>
<span id="L2329" class="LineNr">2329 </span>  memory-should-contain [
<span id="L2330" class="LineNr">2330 </span>   <span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>  <span class="Comment"># cursor-row</span>
<span id="L2331" class="LineNr">2331 </span>   <span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># cursor-column</span>
<span id="L2332" class="LineNr">2332 </span>  ]
<span id="L2333" class="LineNr">2333 </span>]
<span id="L2334" class="LineNr">2334 </span>
<span id="L2335" class="LineNr">2335 </span><span class="Comment"># line wrapping twice (taking up 3 screen lines)</span>
<span id="L2336" class="LineNr">2336 </span><span class="muScenario">scenario</span> editor-deletes-to-start-of-wrapped-line-with-ctrl-u-3 [
<span id="L2337" class="LineNr">2337 </span>  <span class="Constant">local-scope</span>
<span id="L2338" class="LineNr">2338 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">10/height</span>
<span id="L2339" class="LineNr">2339 </span>  <span class="Comment"># third line starts out wrapping</span>
<span id="L2340" class="LineNr">2340 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[1</span>
<span id="L2341" class="LineNr">2341 </span><span class="Constant">2</span>
<span id="L2342" class="LineNr">2342 </span><span class="Constant">3456789abcd</span>
<span id="L2343" class="LineNr">2343 </span><span class="Constant">e]</span>
<span id="L2344" class="LineNr">2344 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L2345" class="LineNr">2345 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2346" class="LineNr">2346 </span>  assume-console [
<span id="L2347" class="LineNr">2347 </span>    left-click<span class="Constant"> 4</span>,<span class="Constant"> 1</span>  <span class="Comment"># on '8'</span>
<span id="L2348" class="LineNr">2348 </span>  ]
<span id="L2349" class="LineNr">2349 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2350" class="LineNr">2350 </span>  screen-should-contain [
<span id="L2351" class="LineNr">2351 </span>   <span class="Constant"> .          .</span>
<span id="L2352" class="LineNr">2352 </span>   <span class="Constant"> .1         .</span>
<span id="L2353" class="LineNr">2353 </span>   <span class="Constant"> .2         .</span>
<span id="L2354" class="LineNr">2354 </span>   <span class="Constant"> .3456↩     .</span>
<span id="L2355" class="LineNr">2355 </span>   <span class="Constant"> .789a↩     .</span>
<span id="L2356" class="LineNr">2356 </span>   <span class="Constant"> .bcd       .</span>
<span id="L2357" class="LineNr">2357 </span>   <span class="Constant"> .e         .</span>
<span id="L2358" class="LineNr">2358 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2359" class="LineNr">2359 </span>   <span class="Constant"> .          .</span>
<span id="L2360" class="LineNr">2360 </span>  ]
<span id="L2361" class="LineNr">2361 </span>  assume-console [
<span id="L2362" class="LineNr">2362 </span>    left-click<span class="Constant"> 5</span>,<span class="Constant"> 1</span>
<span id="L2363" class="LineNr">2363 </span>    press ctrl-u
<span id="L2364" class="LineNr">2364 </span>  ]
<span id="L2365" class="LineNr">2365 </span>  run [
<span id="L2366" class="LineNr">2366 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2367" class="LineNr">2367 </span>    10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L2368" class="LineNr">2368 </span>    11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L2369" class="LineNr">2369 </span>  ]
<span id="L2370" class="LineNr">2370 </span>  screen-should-contain [
<span id="L2371" class="LineNr">2371 </span>   <span class="Constant"> .          .</span>
<span id="L2372" class="LineNr">2372 </span>   <span class="Constant"> .1         .</span>
<span id="L2373" class="LineNr">2373 </span>   <span class="Constant"> .2         .</span>
<span id="L2374" class="LineNr">2374 </span>   <span class="Constant"> .cd        .</span>
<span id="L2375" class="LineNr">2375 </span>   <span class="Constant"> .e         .</span>
<span id="L2376" class="LineNr">2376 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2377" class="LineNr">2377 </span>   <span class="Constant"> .          .</span>
<span id="L2378" class="LineNr">2378 </span>  ]
<span id="L2379" class="LineNr">2379 </span>  <span class="Comment"># make sure we adjusted cursor-row</span>
<span id="L2380" class="LineNr">2380 </span>  memory-should-contain [
<span id="L2381" class="LineNr">2381 </span>   <span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>  <span class="Comment"># cursor-row</span>
<span id="L2382" class="LineNr">2382 </span>   <span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># cursor-column</span>
<span id="L2383" class="LineNr">2383 </span>  ]
<span id="L2384" class="LineNr">2384 </span>]
<span id="L2385" class="LineNr">2385 </span>
<span id="L2386" class="LineNr">2386 </span><span class="Comment"># adjusting cursor row at the top of the screen</span>
<span id="L2387" class="LineNr">2387 </span><span class="muScenario">scenario</span> editor-deletes-to-start-of-wrapped-line-with-ctrl-u-4 [
<span id="L2388" class="LineNr">2388 </span>  <span class="Constant">local-scope</span>
<span id="L2389" class="LineNr">2389 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">10/height</span>
<span id="L2390" class="LineNr">2390 </span>  <span class="Comment"># first line starts out wrapping</span>
<span id="L2391" class="LineNr">2391 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[1234567</span>
<span id="L2392" class="LineNr">2392 </span><span class="Constant">89]</span>
<span id="L2393" class="LineNr">2393 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L2394" class="LineNr">2394 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2395" class="LineNr">2395 </span>  screen-should-contain [
<span id="L2396" class="LineNr">2396 </span>   <span class="Constant"> .          .</span>
<span id="L2397" class="LineNr">2397 </span>   <span class="Constant"> .1234↩     .</span>
<span id="L2398" class="LineNr">2398 </span>   <span class="Constant"> .567       .</span>
<span id="L2399" class="LineNr">2399 </span>   <span class="Constant"> .89        .</span>
<span id="L2400" class="LineNr">2400 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2401" class="LineNr">2401 </span>   <span class="Constant"> .          .</span>
<span id="L2402" class="LineNr">2402 </span>  ]
<span id="L2403" class="LineNr">2403 </span>  <span class="Comment"># position cursor on second screen line (after the wrap) and hit ctrl-u</span>
<span id="L2404" class="LineNr">2404 </span>  assume-console [
<span id="L2405" class="LineNr">2405 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
<span id="L2406" class="LineNr">2406 </span>    press ctrl-u
<span id="L2407" class="LineNr">2407 </span>  ]
<span id="L2408" class="LineNr">2408 </span>  run [
<span id="L2409" class="LineNr">2409 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2410" class="LineNr">2410 </span>    10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L2411" class="LineNr">2411 </span>    11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L2412" class="LineNr">2412 </span>  ]
<span id="L2413" class="LineNr">2413 </span>  screen-should-contain [
<span id="L2414" class="LineNr">2414 </span>   <span class="Constant"> .          .</span>
<span id="L2415" class="LineNr">2415 </span>   <span class="Constant"> .67        .</span>
<span id="L2416" class="LineNr">2416 </span>   <span class="Constant"> .89        .</span>
<span id="L2417" class="LineNr">2417 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2418" class="LineNr">2418 </span>   <span class="Constant"> .          .</span>
<span id="L2419" class="LineNr">2419 </span>  ]
<span id="L2420" class="LineNr">2420 </span>  <span class="Comment"># cursor moves up to screen line 1</span>
<span id="L2421" class="LineNr">2421 </span>  memory-should-contain [
<span id="L2422" class="LineNr">2422 </span>   <span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># cursor-row</span>
<span id="L2423" class="LineNr">2423 </span>   <span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># cursor-column</span>
<span id="L2424" class="LineNr">2424 </span>  ]
<span id="L2425" class="LineNr">2425 </span>]
<span id="L2426" class="LineNr">2426 </span>
<span id="L2427" class="LineNr">2427 </span><span class="Comment"># screen begins part-way through a wrapping line</span>
<span id="L2428" class="LineNr">2428 </span><span class="muScenario">scenario</span> editor-deletes-to-start-of-wrapped-line-with-ctrl-u-5 [
<span id="L2429" class="LineNr">2429 </span>  <span class="Constant">local-scope</span>
<span id="L2430" class="LineNr">2430 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">10/height</span>
<span id="L2431" class="LineNr">2431 </span>  <span class="Comment"># third line starts out wrapping</span>
<span id="L2432" class="LineNr">2432 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[1</span>
<span id="L2433" class="LineNr">2433 </span><span class="Constant">2</span>
<span id="L2434" class="LineNr">2434 </span><span class="Constant">345678</span>
<span id="L2435" class="LineNr">2435 </span><span class="Constant">9]</span>
<span id="L2436" class="LineNr">2436 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L2437" class="LineNr">2437 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2438" class="LineNr">2438 </span>  <span class="Comment"># position the '78' line at the top of the screen</span>
<span id="L2439" class="LineNr">2439 </span>  assume-console [
<span id="L2440" class="LineNr">2440 </span>    left-click<span class="Constant"> 4</span>,<span class="Constant"> 1</span>  <span class="Comment"># on '8'</span>
<span id="L2441" class="LineNr">2441 </span>    press ctrl-t
<span id="L2442" class="LineNr">2442 </span>  ]
<span id="L2443" class="LineNr">2443 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2444" class="LineNr">2444 </span>  screen-should-contain [
<span id="L2445" class="LineNr">2445 </span>   <span class="Constant"> .          .</span>
<span id="L2446" class="LineNr">2446 </span>   <span class="Constant"> .78        .</span>
<span id="L2447" class="LineNr">2447 </span>   <span class="Constant"> .9         .</span>
<span id="L2448" class="LineNr">2448 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2449" class="LineNr">2449 </span>   <span class="Constant"> .          .</span>
<span id="L2450" class="LineNr">2450 </span>  ]
<span id="L2451" class="LineNr">2451 </span>  assume-console [
<span id="L2452" class="LineNr">2452 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
<span id="L2453" class="LineNr">2453 </span>    press ctrl-u
<span id="L2454" class="LineNr">2454 </span>  ]
<span id="L2455" class="LineNr">2455 </span>  run [
<span id="L2456" class="LineNr">2456 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2457" class="LineNr">2457 </span>    10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L2458" class="LineNr">2458 </span>    11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L2459" class="LineNr">2459 </span>  ]
<span id="L2460" class="LineNr">2460 </span>  <span class="Comment"># make sure we updated top-of-screen correctly</span>
<span id="L2461" class="LineNr">2461 </span>  screen-should-contain [
<span id="L2462" class="LineNr">2462 </span>   <span class="Constant"> .          .</span>
<span id="L2463" class="LineNr">2463 </span>   <span class="Constant"> .8         .</span>
<span id="L2464" class="LineNr">2464 </span>   <span class="Constant"> .9         .</span>
<span id="L2465" class="LineNr">2465 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2466" class="LineNr">2466 </span>   <span class="Constant"> .          .</span>
<span id="L2467" class="LineNr">2467 </span>  ]
<span id="L2468" class="LineNr">2468 </span>  memory-should-contain [
<span id="L2469" class="LineNr">2469 </span>   <span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># cursor-row</span>
<span id="L2470" class="LineNr">2470 </span>   <span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># cursor-column</span>
<span id="L2471" class="LineNr">2471 </span>  ]
<span id="L2472" class="LineNr">2472 </span>  <span class="Comment"># the entire line is deleted, even the part not shown on screen</span>
<span id="L2473" class="LineNr">2473 </span>  assume-console [
<span id="L2474" class="LineNr">2474 </span>    press up-arrow
<span id="L2475" class="LineNr">2475 </span>  ]
<span id="L2476" class="LineNr">2476 </span>  run [
<span id="L2477" class="LineNr">2477 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2478" class="LineNr">2478 </span>  ]
<span id="L2479" class="LineNr">2479 </span>  screen-should-contain [
<span id="L2480" class="LineNr">2480 </span>   <span class="Constant"> .          .</span>
<span id="L2481" class="LineNr">2481 </span>   <span class="Constant"> .2         .</span>
<span id="L2482" class="LineNr">2482 </span>   <span class="Constant"> .8         .</span>
<span id="L2483" class="LineNr">2483 </span>   <span class="Constant"> .9         .</span>
<span id="L2484" class="LineNr">2484 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2485" class="LineNr">2485 </span>   <span class="Constant"> .          .</span>
<span id="L2486" class="LineNr">2486 </span>  ]
<span id="L2487" class="LineNr">2487 </span>]
<span id="L2488" class="LineNr">2488 </span>
<span id="L2489" class="LineNr">2489 </span><span class="Comment"># screen begins part-way through a line wrapping twice (taking up 3 screen lines)</span>
<span id="L2490" class="LineNr">2490 </span><span class="muScenario">scenario</span> editor-deletes-to-start-of-wrapped-line-with-ctrl-u-6 [
<span id="L2491" class="LineNr">2491 </span>  <span class="Constant">local-scope</span>
<span id="L2492" class="LineNr">2492 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">10/height</span>
<span id="L2493" class="LineNr">2493 </span>  <span class="Comment"># third line starts out wrapping</span>
<span id="L2494" class="LineNr">2494 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[1</span>
<span id="L2495" class="LineNr">2495 </span><span class="Constant">2</span>
<span id="L2496" class="LineNr">2496 </span><span class="Constant">3456789abcd</span>
<span id="L2497" class="LineNr">2497 </span><span class="Constant">e]</span>
<span id="L2498" class="LineNr">2498 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L2499" class="LineNr">2499 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2500" class="LineNr">2500 </span>  <span class="Comment"># position the 'bcd' line at the top of the screen</span>
<span id="L2501" class="LineNr">2501 </span>  assume-console [
<span id="L2502" class="LineNr">2502 </span>    left-click<span class="Constant"> 4</span>,<span class="Constant"> 1</span>  <span class="Comment"># on '8'</span>
<span id="L2503" class="LineNr">2503 </span>    press ctrl-t
<span id="L2504" class="LineNr">2504 </span>    press ctrl-s  <span class="Comment"># now on 'c'</span>
<span id="L2505" class="LineNr">2505 </span>  ]
<span id="L2506" class="LineNr">2506 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2507" class="LineNr">2507 </span>  screen-should-contain [
<span id="L2508" class="LineNr">2508 </span>   <span class="Constant"> .          .</span>
<span id="L2509" class="LineNr">2509 </span>   <span class="Constant"> .bcd       .</span>
<span id="L2510" class="LineNr">2510 </span>   <span class="Constant"> .e         .</span>
<span id="L2511" class="LineNr">2511 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2512" class="LineNr">2512 </span>   <span class="Constant"> .          .</span>
<span id="L2513" class="LineNr">2513 </span>  ]
<span id="L2514" class="LineNr">2514 </span>  assume-console [
<span id="L2515" class="LineNr">2515 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
<span id="L2516" class="LineNr">2516 </span>    press ctrl-u
<span id="L2517" class="LineNr">2517 </span>  ]
<span id="L2518" class="LineNr">2518 </span>  run [
<span id="L2519" class="LineNr">2519 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2520" class="LineNr">2520 </span>    10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L2521" class="LineNr">2521 </span>    11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L2522" class="LineNr">2522 </span>  ]
<span id="L2523" class="LineNr">2523 </span>  <span class="Comment"># make sure we updated top-of-screen correctly</span>
<span id="L2524" class="LineNr">2524 </span>  screen-should-contain [
<span id="L2525" class="LineNr">2525 </span>   <span class="Constant"> .          .</span>
<span id="L2526" class="LineNr">2526 </span>   <span class="Constant"> .cd        .</span>
<span id="L2527" class="LineNr">2527 </span>   <span class="Constant"> .e         .</span>
<span id="L2528" class="LineNr">2528 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2529" class="LineNr">2529 </span>   <span class="Constant"> .          .</span>
<span id="L2530" class="LineNr">2530 </span>  ]
<span id="L2531" class="LineNr">2531 </span>  memory-should-contain [
<span id="L2532" class="LineNr">2532 </span>   <span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># cursor-row</span>
<span id="L2533" class="LineNr">2533 </span>   <span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># cursor-column</span>
<span id="L2534" class="LineNr">2534 </span>  ]
<span id="L2535" class="LineNr">2535 </span>  <span class="Comment"># the entire line is deleted, even the part not shown on screen</span>
<span id="L2536" class="LineNr">2536 </span>  assume-console [
<span id="L2537" class="LineNr">2537 </span>    press up-arrow
<span id="L2538" class="LineNr">2538 </span>  ]
<span id="L2539" class="LineNr">2539 </span>  run [
<span id="L2540" class="LineNr">2540 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2541" class="LineNr">2541 </span>  ]
<span id="L2542" class="LineNr">2542 </span>  screen-should-contain [
<span id="L2543" class="LineNr">2543 </span>   <span class="Constant"> .          .</span>
<span id="L2544" class="LineNr">2544 </span>   <span class="Constant"> .2         .</span>
<span id="L2545" class="LineNr">2545 </span>   <span class="Constant"> .cd        .</span>
<span id="L2546" class="LineNr">2546 </span>   <span class="Constant"> .e         .</span>
<span id="L2547" class="LineNr">2547 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2548" class="LineNr">2548 </span>   <span class="Constant"> .          .</span>
<span id="L2549" class="LineNr">2549 </span>  ]
<span id="L2550" class="LineNr">2550 </span>]
<span id="L2551" class="LineNr">2551 </span>
<span id="L2552" class="LineNr">2552 </span><span class="Comment"># ctrl-k - delete text from cursor to end of line (but not the newline)</span>
<span id="L2553" class="LineNr">2553 </span>
<span id="L2554" class="LineNr">2554 </span><span class="muScenario">scenario</span> editor-deletes-to-end-of-line-with-ctrl-k [
<span id="L2555" class="LineNr">2555 </span>  <span class="Constant">local-scope</span>
<span id="L2556" class="LineNr">2556 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L2557" class="LineNr">2557 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L2558" class="LineNr">2558 </span><span class="Constant">456]</span>
<span id="L2559" class="LineNr">2559 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L2560" class="LineNr">2560 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2561" class="LineNr">2561 </span>  $clear-trace
<span id="L2562" class="LineNr">2562 </span>  <span class="Comment"># start on first line, press ctrl-k</span>
<span id="L2563" class="LineNr">2563 </span>  assume-console [
<span id="L2564" class="LineNr">2564 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
<span id="L2565" class="LineNr">2565 </span>    press ctrl-k
<span id="L2566" class="LineNr">2566 </span>  ]
<span id="L2567" class="LineNr">2567 </span>  run [
<span id="L2568" class="LineNr">2568 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2569" class="LineNr">2569 </span>  ]
<span id="L2570" class="LineNr">2570 </span>  <span class="Comment"># cursor deletes to end of line</span>
<span id="L2571" class="LineNr">2571 </span>  screen-should-contain [
<span id="L2572" class="LineNr">2572 </span>   <span class="Constant"> .          .</span>
<span id="L2573" class="LineNr">2573 </span>   <span class="Constant"> .1         .</span>
<span id="L2574" class="LineNr">2574 </span>   <span class="Constant"> .456       .</span>
<span id="L2575" class="LineNr">2575 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2576" class="LineNr">2576 </span>   <span class="Constant"> .          .</span>
<span id="L2577" class="LineNr">2577 </span>  ]
<span id="L2578" class="LineNr">2578 </span>  check-trace-count-for-label<span class="Constant"> 9</span>, <span class="Constant">[print-character]</span>
<span id="L2579" class="LineNr">2579 </span>]
<span id="L2580" class="LineNr">2580 </span>
<span id="L2581" class="LineNr">2581 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L2582" class="LineNr">2582 </span>  <span class="Delimiter">{</span>
<span id="L2583" class="LineNr">2583 </span>    delete-to-end-of-line?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">11/ctrl-k</span>
<span id="L2584" class="LineNr">2584 </span>    <span class="muControl">break-unless</span> delete-to-end-of-line?
<span id="L2585" class="LineNr">2585 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L2585'>&lt;begin-delete-to-end-of-line&gt;</a></span>
<span id="L2586" class="LineNr">2586 </span>    deleted-cells:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2612'>delete-to-end-of-line</a> editor
<span id="L2587" class="LineNr">2587 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L2587'>&lt;end-delete-to-end-of-line&gt;</a></span>
<span id="L2588" class="LineNr">2588 </span>    <span class="Comment"># checks if we can do a minimal render and if we can it will do a minimal render</span>
<span id="L2589" class="LineNr">2589 </span>    go-render?:bool <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2594'>minimal-render-for-ctrl-k</a> <a href='../081print.mu.html#L16'>screen</a>, editor, deleted-cells
<span id="L2590" class="LineNr">2590 </span>   <span class="muControl"> return</span>
<span id="L2591" class="LineNr">2591 </span>  <span class="Delimiter">}</span>
<span id="L2592" class="LineNr">2592 </span>]
<span id="L2593" class="LineNr">2593 </span>
<span id="L2594" class="LineNr">2594 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L2594'>minimal-render-for-ctrl-k</a> <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a>, editor:&amp;:editor, deleted-cells:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char<span class="muRecipe"> -&gt; </span>go-render?:bool, <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a> [
<span id="L2595" class="LineNr">2595 </span>  <span class="Constant">local-scope</span>
<span id="L2596" class="LineNr">2596 </span>  <span class="Constant">load-inputs</span>
<span id="L2597" class="LineNr">2597 </span>  <span class="Comment"># if we deleted nothing, there's nothing to render</span>
<span id="L2598" class="LineNr">2598 </span>  <span class="muControl">return-unless</span> deleted-cells,<span class="Constant"> false/dont-render</span>
<span id="L2599" class="LineNr">2599 </span>  <span class="Comment"># if the line used to wrap before, give up and render the whole screen</span>
<span id="L2600" class="LineNr">2600 </span>  curr-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L2601" class="LineNr">2601 </span>  num-deleted-cells:num <span class="Special">&lt;-</span> length deleted-cells
<span id="L2602" class="LineNr">2602 </span>  old-row-len:num <span class="Special">&lt;-</span> add curr-column, num-deleted-cells
<span id="L2603" class="LineNr">2603 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L2604" class="LineNr">2604 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L2605" class="LineNr">2605 </span>  end:num <span class="Special">&lt;-</span> subtract right, left
<span id="L2606" class="LineNr">2606 </span>  wrap?:bool <span class="Special">&lt;-</span> greater-or-equal old-row-len, end
<span id="L2607" class="LineNr">2607 </span>  <span class="muControl">return-if</span> wrap?,<span class="Constant"> true/go-render</span>
<span id="L2608" class="LineNr">2608 </span>  <a href='../081print.mu.html#L553'>clear-line-until</a> <a href='../081print.mu.html#L16'>screen</a>, right
<span id="L2609" class="LineNr">2609 </span> <span class="muControl"> return</span><span class="Constant"> false/dont-render</span>
<span id="L2610" class="LineNr">2610 </span>]
<span id="L2611" class="LineNr">2611 </span>
<span id="L2612" class="LineNr">2612 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L2612'>delete-to-end-of-line</a> editor:&amp;:editor<span class="muRecipe"> -&gt; </span>result:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char, editor:&amp;:editor [
<span id="L2613" class="LineNr">2613 </span>  <span class="Constant">local-scope</span>
<span id="L2614" class="LineNr">2614 </span>  <span class="Constant">load-inputs</span>
<span id="L2615" class="LineNr">2615 </span>  <span class="Comment"># compute range to delete</span>
<span id="L2616" class="LineNr">2616 </span>  start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L2617" class="LineNr">2617 </span>  end:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> start
<span id="L2618" class="LineNr">2618 </span>  <span class="Delimiter">{</span>
<span id="L2619" class="LineNr">2619 </span>    at-end-of-text?:bool <span class="Special">&lt;-</span> equal end,<span class="Constant"> null</span>
<span id="L2620" class="LineNr">2620 </span>    <span class="muControl">break-if</span> at-end-of-text?
<span id="L2621" class="LineNr">2621 </span>    curr:char <span class="Special">&lt;-</span> get *end, <span class="Constant">value:offset</span>
<span id="L2622" class="LineNr">2622 </span>    at-end-of-line?:bool <span class="Special">&lt;-</span> equal curr, <span class="Constant">10/newline</span>
<span id="L2623" class="LineNr">2623 </span>    <span class="muControl">break-if</span> at-end-of-line?
<span id="L2624" class="LineNr">2624 </span>    end <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> end
<span id="L2625" class="LineNr">2625 </span>   <span class="muControl"> loop</span>
<span id="L2626" class="LineNr">2626 </span>  <span class="Delimiter">}</span>
<span id="L2627" class="LineNr">2627 </span>  <span class="Comment"># snip it out</span>
<span id="L2628" class="LineNr">2628 </span>  result <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> start
<span id="L2629" class="LineNr">2629 </span>  <a href='../065duplex_list.mu.html#L391'>remove-between</a> start, end
<span id="L2630" class="LineNr">2630 </span>]
<span id="L2631" class="LineNr">2631 </span>
<span id="L2632" class="LineNr">2632 </span><span class="muScenario">scenario</span> editor-deletes-to-end-of-line-with-ctrl-k-2 [
<span id="L2633" class="LineNr">2633 </span>  <span class="Constant">local-scope</span>
<span id="L2634" class="LineNr">2634 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L2635" class="LineNr">2635 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L2636" class="LineNr">2636 </span><span class="Constant">456]</span>
<span id="L2637" class="LineNr">2637 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L2638" class="LineNr">2638 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2639" class="LineNr">2639 </span>  $clear-trace
<span id="L2640" class="LineNr">2640 </span>  <span class="Comment"># start on second line (no newline after), press ctrl-k</span>
<span id="L2641" class="LineNr">2641 </span>  assume-console [
<span id="L2642" class="LineNr">2642 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
<span id="L2643" class="LineNr">2643 </span>    press ctrl-k
<span id="L2644" class="LineNr">2644 </span>  ]
<span id="L2645" class="LineNr">2645 </span>  run [
<span id="L2646" class="LineNr">2646 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2647" class="LineNr">2647 </span>  ]
<span id="L2648" class="LineNr">2648 </span>  <span class="Comment"># cursor deletes to end of line</span>
<span id="L2649" class="LineNr">2649 </span>  screen-should-contain [
<span id="L2650" class="LineNr">2650 </span>   <span class="Constant"> .          .</span>
<span id="L2651" class="LineNr">2651 </span>   <span class="Constant"> .123       .</span>
<span id="L2652" class="LineNr">2652 </span>   <span class="Constant"> .4         .</span>
<span id="L2653" class="LineNr">2653 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2654" class="LineNr">2654 </span>   <span class="Constant"> .          .</span>
<span id="L2655" class="LineNr">2655 </span>  ]
<span id="L2656" class="LineNr">2656 </span>  check-trace-count-for-label<span class="Constant"> 9</span>, <span class="Constant">[print-character]</span>
<span id="L2657" class="LineNr">2657 </span>]
<span id="L2658" class="LineNr">2658 </span>
<span id="L2659" class="LineNr">2659 </span><span class="muScenario">scenario</span> editor-deletes-to-end-of-line-with-ctrl-k-3 [
<span id="L2660" class="LineNr">2660 </span>  <span class="Constant">local-scope</span>
<span id="L2661" class="LineNr">2661 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L2662" class="LineNr">2662 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L2663" class="LineNr">2663 </span><span class="Constant">456]</span>
<span id="L2664" class="LineNr">2664 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L2665" class="LineNr">2665 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2666" class="LineNr">2666 </span>  $clear-trace
<span id="L2667" class="LineNr">2667 </span>  <span class="Comment"># start at end of line</span>
<span id="L2668" class="LineNr">2668 </span>  assume-console [
<span id="L2669" class="LineNr">2669 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 2</span>
<span id="L2670" class="LineNr">2670 </span>    press ctrl-k
<span id="L2671" class="LineNr">2671 </span>  ]
<span id="L2672" class="LineNr">2672 </span>  run [
<span id="L2673" class="LineNr">2673 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2674" class="LineNr">2674 </span>  ]
<span id="L2675" class="LineNr">2675 </span>  <span class="Comment"># cursor deletes just last character</span>
<span id="L2676" class="LineNr">2676 </span>  screen-should-contain [
<span id="L2677" class="LineNr">2677 </span>   <span class="Constant"> .          .</span>
<span id="L2678" class="LineNr">2678 </span>   <span class="Constant"> .12        .</span>
<span id="L2679" class="LineNr">2679 </span>   <span class="Constant"> .456       .</span>
<span id="L2680" class="LineNr">2680 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2681" class="LineNr">2681 </span>   <span class="Constant"> .          .</span>
<span id="L2682" class="LineNr">2682 </span>  ]
<span id="L2683" class="LineNr">2683 </span>  check-trace-count-for-label<span class="Constant"> 8</span>, <span class="Constant">[print-character]</span>
<span id="L2684" class="LineNr">2684 </span>]
<span id="L2685" class="LineNr">2685 </span>
<span id="L2686" class="LineNr">2686 </span><span class="muScenario">scenario</span> editor-deletes-to-end-of-line-with-ctrl-k-4 [
<span id="L2687" class="LineNr">2687 </span>  <span class="Constant">local-scope</span>
<span id="L2688" class="LineNr">2688 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L2689" class="LineNr">2689 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L2690" class="LineNr">2690 </span><span class="Constant">456]</span>
<span id="L2691" class="LineNr">2691 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L2692" class="LineNr">2692 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2693" class="LineNr">2693 </span>  $clear-trace
<span id="L2694" class="LineNr">2694 </span>  <span class="Comment"># start past end of line</span>
<span id="L2695" class="LineNr">2695 </span>  assume-console [
<span id="L2696" class="LineNr">2696 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
<span id="L2697" class="LineNr">2697 </span>    press ctrl-k
<span id="L2698" class="LineNr">2698 </span>  ]
<span id="L2699" class="LineNr">2699 </span>  run [
<span id="L2700" class="LineNr">2700 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2701" class="LineNr">2701 </span>  ]
<span id="L2702" class="LineNr">2702 </span>  <span class="Comment"># cursor deletes nothing</span>
<span id="L2703" class="LineNr">2703 </span>  screen-should-contain [
<span id="L2704" class="LineNr">2704 </span>   <span class="Constant"> .          .</span>
<span id="L2705" class="LineNr">2705 </span>   <span class="Constant"> .123       .</span>
<span id="L2706" class="LineNr">2706 </span>   <span class="Constant"> .456       .</span>
<span id="L2707" class="LineNr">2707 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2708" class="LineNr">2708 </span>   <span class="Constant"> .          .</span>
<span id="L2709" class="LineNr">2709 </span>  ]
<span id="L2710" class="LineNr">2710 </span>  check-trace-count-for-label<span class="Constant"> 7</span>, <span class="Constant">[print-character]</span>
<span id="L2711" class="LineNr">2711 </span>]
<span id="L2712" class="LineNr">2712 </span>
<span id="L2713" class="LineNr">2713 </span><span class="muScenario">scenario</span> editor-deletes-to-end-of-line-with-ctrl-k-5 [
<span id="L2714" class="LineNr">2714 </span>  <span class="Constant">local-scope</span>
<span id="L2715" class="LineNr">2715 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L2716" class="LineNr">2716 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L2717" class="LineNr">2717 </span><span class="Constant">456]</span>
<span id="L2718" class="LineNr">2718 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L2719" class="LineNr">2719 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2720" class="LineNr">2720 </span>  $clear-trace
<span id="L2721" class="LineNr">2721 </span>  <span class="Comment"># start at end of text</span>
<span id="L2722" class="LineNr">2722 </span>  assume-console [
<span id="L2723" class="LineNr">2723 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 2</span>
<span id="L2724" class="LineNr">2724 </span>    press ctrl-k
<span id="L2725" class="LineNr">2725 </span>  ]
<span id="L2726" class="LineNr">2726 </span>  run [
<span id="L2727" class="LineNr">2727 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2728" class="LineNr">2728 </span>  ]
<span id="L2729" class="LineNr">2729 </span>  <span class="Comment"># cursor deletes just the final character</span>
<span id="L2730" class="LineNr">2730 </span>  screen-should-contain [
<span id="L2731" class="LineNr">2731 </span>   <span class="Constant"> .          .</span>
<span id="L2732" class="LineNr">2732 </span>   <span class="Constant"> .123       .</span>
<span id="L2733" class="LineNr">2733 </span>   <span class="Constant"> .45        .</span>
<span id="L2734" class="LineNr">2734 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2735" class="LineNr">2735 </span>   <span class="Constant"> .          .</span>
<span id="L2736" class="LineNr">2736 </span>  ]
<span id="L2737" class="LineNr">2737 </span>  check-trace-count-for-label<span class="Constant"> 8</span>, <span class="Constant">[print-character]</span>
<span id="L2738" class="LineNr">2738 </span>]
<span id="L2739" class="LineNr">2739 </span>
<span id="L2740" class="LineNr">2740 </span><span class="muScenario">scenario</span> editor-deletes-to-end-of-line-with-ctrl-k-6 [
<span id="L2741" class="LineNr">2741 </span>  <span class="Constant">local-scope</span>
<span id="L2742" class="LineNr">2742 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L2743" class="LineNr">2743 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L2744" class="LineNr">2744 </span><span class="Constant">456]</span>
<span id="L2745" class="LineNr">2745 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L2746" class="LineNr">2746 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2747" class="LineNr">2747 </span>  $clear-trace
<span id="L2748" class="LineNr">2748 </span>  <span class="Comment"># start past end of text</span>
<span id="L2749" class="LineNr">2749 </span>  assume-console [
<span id="L2750" class="LineNr">2750 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
<span id="L2751" class="LineNr">2751 </span>    press ctrl-k
<span id="L2752" class="LineNr">2752 </span>  ]
<span id="L2753" class="LineNr">2753 </span>  run [
<span id="L2754" class="LineNr">2754 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2755" class="LineNr">2755 </span>  ]
<span id="L2756" class="LineNr">2756 </span>  <span class="Comment"># cursor deletes nothing</span>
<span id="L2757" class="LineNr">2757 </span>  screen-should-contain [
<span id="L2758" class="LineNr">2758 </span>   <span class="Constant"> .          .</span>
<span id="L2759" class="LineNr">2759 </span>   <span class="Constant"> .123       .</span>
<span id="L2760" class="LineNr">2760 </span>   <span class="Constant"> .456       .</span>
<span id="L2761" class="LineNr">2761 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2762" class="LineNr">2762 </span>   <span class="Constant"> .          .</span>
<span id="L2763" class="LineNr">2763 </span>  ]
<span id="L2764" class="LineNr">2764 </span>  <span class="Comment"># no prints necessary</span>
<span id="L2765" class="LineNr">2765 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L2766" class="LineNr">2766 </span>]
<span id="L2767" class="LineNr">2767 </span>
<span id="L2768" class="LineNr">2768 </span><span class="muScenario">scenario</span> editor-deletes-to-end-of-wrapped-line-with-ctrl-k [
<span id="L2769" class="LineNr">2769 </span>  <span class="Constant">local-scope</span>
<span id="L2770" class="LineNr">2770 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L2771" class="LineNr">2771 </span>  <span class="Comment"># create an editor with the first line wrapping to a second screen row</span>
<span id="L2772" class="LineNr">2772 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[1234</span>
<span id="L2773" class="LineNr">2773 </span><span class="Constant">567]</span>
<span id="L2774" class="LineNr">2774 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">4/right</span>
<span id="L2775" class="LineNr">2775 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2776" class="LineNr">2776 </span>  $clear-trace
<span id="L2777" class="LineNr">2777 </span>  <span class="Comment"># delete all of the first wrapped line</span>
<span id="L2778" class="LineNr">2778 </span>  assume-console [
<span id="L2779" class="LineNr">2779 </span>    press ctrl-k
<span id="L2780" class="LineNr">2780 </span>  ]
<span id="L2781" class="LineNr">2781 </span>  run [
<span id="L2782" class="LineNr">2782 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2783" class="LineNr">2783 </span>  ]
<span id="L2784" class="LineNr">2784 </span>  <span class="Comment"># screen shows an empty unwrapped first line</span>
<span id="L2785" class="LineNr">2785 </span>  screen-should-contain [
<span id="L2786" class="LineNr">2786 </span>   <span class="Constant"> .          .</span>
<span id="L2787" class="LineNr">2787 </span>   <span class="Constant"> .          .</span>
<span id="L2788" class="LineNr">2788 </span>   <span class="Constant"> .567       .</span>
<span id="L2789" class="LineNr">2789 </span>   <span class="Constant"> .╌╌╌╌      .</span>
<span id="L2790" class="LineNr">2790 </span>   <span class="Constant"> .          .</span>
<span id="L2791" class="LineNr">2791 </span>  ]
<span id="L2792" class="LineNr">2792 </span>  <span class="Comment"># entire screen is refreshed</span>
<span id="L2793" class="LineNr">2793 </span>  check-trace-count-for-label<span class="Constant"> 16</span>, <span class="Constant">[print-character]</span>
<span id="L2794" class="LineNr">2794 </span>]
<span id="L2795" class="LineNr">2795 </span>
<span id="L2796" class="LineNr">2796 </span><span class="Comment"># scroll down if necessary</span>
<span id="L2797" class="LineNr">2797 </span>
<span id="L2798" class="LineNr">2798 </span><span class="muScenario">scenario</span> editor-can-scroll-down-using-arrow-keys [
<span id="L2799" class="LineNr">2799 </span>  <span class="Constant">local-scope</span>
<span id="L2800" class="LineNr">2800 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L2801" class="LineNr">2801 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L2802" class="LineNr">2802 </span>  <span class="Comment"># initialize editor with &gt;3 lines</span>
<span id="L2803" class="LineNr">2803 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L2804" class="LineNr">2804 </span><span class="Constant">b</span>
<span id="L2805" class="LineNr">2805 </span><span class="Constant">c</span>
<span id="L2806" class="LineNr">2806 </span><span class="Constant">d]</span>
<span id="L2807" class="LineNr">2807 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L2808" class="LineNr">2808 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2809" class="LineNr">2809 </span>  screen-should-contain [
<span id="L2810" class="LineNr">2810 </span>   <span class="Constant"> .          .</span>
<span id="L2811" class="LineNr">2811 </span>   <span class="Constant"> .a         .</span>
<span id="L2812" class="LineNr">2812 </span>   <span class="Constant"> .b         .</span>
<span id="L2813" class="LineNr">2813 </span>   <span class="Constant"> .c         .</span>
<span id="L2814" class="LineNr">2814 </span>  ]
<span id="L2815" class="LineNr">2815 </span>  <span class="Comment"># position cursor at last line, then try to move further down</span>
<span id="L2816" class="LineNr">2816 </span>  assume-console [
<span id="L2817" class="LineNr">2817 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
<span id="L2818" class="LineNr">2818 </span>    press down-arrow
<span id="L2819" class="LineNr">2819 </span>  ]
<span id="L2820" class="LineNr">2820 </span>  run [
<span id="L2821" class="LineNr">2821 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2822" class="LineNr">2822 </span>  ]
<span id="L2823" class="LineNr">2823 </span>  <span class="Comment"># screen slides by one line</span>
<span id="L2824" class="LineNr">2824 </span>  screen-should-contain [
<span id="L2825" class="LineNr">2825 </span>   <span class="Constant"> .          .</span>
<span id="L2826" class="LineNr">2826 </span>   <span class="Constant"> .b         .</span>
<span id="L2827" class="LineNr">2827 </span>   <span class="Constant"> .c         .</span>
<span id="L2828" class="LineNr">2828 </span>   <span class="Constant"> .d         .</span>
<span id="L2829" class="LineNr">2829 </span>  ]
<span id="L2830" class="LineNr">2830 </span>]
<span id="L2831" class="LineNr">2831 </span>
<span id="L2832" class="LineNr">2832 </span><span class="muRecipe">after</span> <span class="Constant">&lt;scroll-down&gt;</span> [
<span id="L2833" class="LineNr">2833 </span>  trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[scroll down]</span>
<span id="L2834" class="LineNr">2834 </span>  top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L2835" class="LineNr">2835 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L2836" class="LineNr">2836 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L2837" class="LineNr">2837 </span>  max:num <span class="Special">&lt;-</span> subtract right, left
<span id="L2838" class="LineNr">2838 </span>  old-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy top-of-screen
<span id="L2839" class="LineNr">2839 </span>  top-of-screen <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2862'>before-start-of-next-line</a> top-of-screen, max
<span id="L2840" class="LineNr">2840 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top-of-screen
<span id="L2841" class="LineNr">2841 </span>  no-movement?:bool <span class="Special">&lt;-</span> equal old-top, top-of-screen
<span id="L2842" class="LineNr">2842 </span>  <span class="muControl">return-if</span> no-movement?,<span class="Constant"> false/don't-render</span>
<span id="L2843" class="LineNr">2843 </span>]
<span id="L2844" class="LineNr">2844 </span>
<span id="L2845" class="LineNr">2845 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L888'>&lt;scroll-down2&gt;</a></span> [
<span id="L2846" class="LineNr">2846 </span>  trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[scroll down]</span>
<span id="L2847" class="LineNr">2847 </span>  top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L2848" class="LineNr">2848 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L2849" class="LineNr">2849 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L2850" class="LineNr">2850 </span>  max:num <span class="Special">&lt;-</span> subtract right, left
<span id="L2851" class="LineNr">2851 </span>  old-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy top-of-screen
<span id="L2852" class="LineNr">2852 </span>  top-of-screen <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2862'>before-start-of-next-line</a> top-of-screen, max
<span id="L2853" class="LineNr">2853 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top-of-screen
<span id="L2854" class="LineNr">2854 </span>  no-movement?:bool <span class="Special">&lt;-</span> equal old-top, top-of-screen
<span id="L2855" class="LineNr">2855 </span>  <span class="muControl">return-if</span> no-movement?
<span id="L2856" class="LineNr">2856 </span>]
<span id="L2857" class="LineNr">2857 </span>
<span id="L2858" class="LineNr">2858 </span><span class="Comment"># Takes a pointer into the doubly-linked list, scans ahead at most 'max'</span>
<span id="L2859" class="LineNr">2859 </span><span class="Comment"># positions until the next newline.</span>
<span id="L2860" class="LineNr">2860 </span><span class="Comment"># Returns original if no next newline.</span>
<span id="L2861" class="LineNr">2861 </span><span class="Comment"># Beware: never return null pointer.</span>
<span id="L2862" class="LineNr">2862 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L2862'>before-start-of-next-line</a> original:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char, max:num<span class="muRecipe"> -&gt; </span>curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char [
<span id="L2863" class="LineNr">2863 </span>  <span class="Constant">local-scope</span>
<span id="L2864" class="LineNr">2864 </span>  <span class="Constant">load-inputs</span>
<span id="L2865" class="LineNr">2865 </span>  count:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
<span id="L2866" class="LineNr">2866 </span>  curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy original
<span id="L2867" class="LineNr">2867 </span>  <span class="Comment"># skip the initial newline if it exists</span>
<span id="L2868" class="LineNr">2868 </span>  <span class="Delimiter">{</span>
<span id="L2869" class="LineNr">2869 </span>    c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
<span id="L2870" class="LineNr">2870 </span>    at-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
<span id="L2871" class="LineNr">2871 </span>    <span class="muControl">break-unless</span> at-newline?
<span id="L2872" class="LineNr">2872 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> curr
<span id="L2873" class="LineNr">2873 </span>    count <span class="Special">&lt;-</span> add count,<span class="Constant"> 1</span>
<span id="L2874" class="LineNr">2874 </span>  <span class="Delimiter">}</span>
<span id="L2875" class="LineNr">2875 </span>  <span class="Delimiter">{</span>
<span id="L2876" class="LineNr">2876 </span>    <span class="muControl">return-unless</span> curr, original
<span id="L2877" class="LineNr">2877 </span>    done?:bool <span class="Special">&lt;-</span> greater-or-equal count, max
<span id="L2878" class="LineNr">2878 </span>    <span class="muControl">break-if</span> done?
<span id="L2879" class="LineNr">2879 </span>    c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
<span id="L2880" class="LineNr">2880 </span>    at-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
<span id="L2881" class="LineNr">2881 </span>    <span class="muControl">break-if</span> at-newline?
<span id="L2882" class="LineNr">2882 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> curr
<span id="L2883" class="LineNr">2883 </span>    count <span class="Special">&lt;-</span> add count,<span class="Constant"> 1</span>
<span id="L2884" class="LineNr">2884 </span>   <span class="muControl"> loop</span>
<span id="L2885" class="LineNr">2885 </span>  <span class="Delimiter">}</span>
<span id="L2886" class="LineNr">2886 </span>  <span class="muControl">return-unless</span> curr, original
<span id="L2887" class="LineNr">2887 </span> <span class="muControl"> return</span> curr
<span id="L2888" class="LineNr">2888 </span>]
<span id="L2889" class="LineNr">2889 </span>
<span id="L2890" class="LineNr">2890 </span><span class="muScenario">scenario</span> editor-scrolls-down-past-wrapped-line-using-arrow-keys [
<span id="L2891" class="LineNr">2891 </span>  <span class="Constant">local-scope</span>
<span id="L2892" class="LineNr">2892 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L2893" class="LineNr">2893 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L2894" class="LineNr">2894 </span>  <span class="Comment"># initialize editor with a long, wrapped line and more than a screen of</span>
<span id="L2895" class="LineNr">2895 </span>  <span class="Comment"># other lines</span>
<span id="L2896" class="LineNr">2896 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abcdef</span>
<span id="L2897" class="LineNr">2897 </span><span class="Constant">g</span>
<span id="L2898" class="LineNr">2898 </span><span class="Constant">h</span>
<span id="L2899" class="LineNr">2899 </span><span class="Constant">i]</span>
<span id="L2900" class="LineNr">2900 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L2901" class="LineNr">2901 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2902" class="LineNr">2902 </span>  screen-should-contain [
<span id="L2903" class="LineNr">2903 </span>   <span class="Constant"> .          .</span>
<span id="L2904" class="LineNr">2904 </span>   <span class="Constant"> .abcd↩     .</span>
<span id="L2905" class="LineNr">2905 </span>   <span class="Constant"> .ef        .</span>
<span id="L2906" class="LineNr">2906 </span>   <span class="Constant"> .g         .</span>
<span id="L2907" class="LineNr">2907 </span>  ]
<span id="L2908" class="LineNr">2908 </span>  <span class="Comment"># position cursor at last line, then try to move further down</span>
<span id="L2909" class="LineNr">2909 </span>  assume-console [
<span id="L2910" class="LineNr">2910 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
<span id="L2911" class="LineNr">2911 </span>    press down-arrow
<span id="L2912" class="LineNr">2912 </span>  ]
<span id="L2913" class="LineNr">2913 </span>  run [
<span id="L2914" class="LineNr">2914 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2915" class="LineNr">2915 </span>  ]
<span id="L2916" class="LineNr">2916 </span>  <span class="Comment"># screen shows partial wrapped line</span>
<span id="L2917" class="LineNr">2917 </span>  screen-should-contain [
<span id="L2918" class="LineNr">2918 </span>   <span class="Constant"> .          .</span>
<span id="L2919" class="LineNr">2919 </span>   <span class="Constant"> .ef        .</span>
<span id="L2920" class="LineNr">2920 </span>   <span class="Constant"> .g         .</span>
<span id="L2921" class="LineNr">2921 </span>   <span class="Constant"> .h         .</span>
<span id="L2922" class="LineNr">2922 </span>  ]
<span id="L2923" class="LineNr">2923 </span>]
<span id="L2924" class="LineNr">2924 </span>
<span id="L2925" class="LineNr">2925 </span><span class="muScenario">scenario</span> editor-scrolls-down-past-wrapped-line-using-arrow-keys-2 [
<span id="L2926" class="LineNr">2926 </span>  <span class="Constant">local-scope</span>
<span id="L2927" class="LineNr">2927 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L2928" class="LineNr">2928 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L2929" class="LineNr">2929 </span>  <span class="Comment"># editor starts with a long line wrapping twice</span>
<span id="L2930" class="LineNr">2930 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abcdefghij</span>
<span id="L2931" class="LineNr">2931 </span><span class="Constant">k</span>
<span id="L2932" class="LineNr">2932 </span><span class="Constant">l</span>
<span id="L2933" class="LineNr">2933 </span><span class="Constant">m]</span>
<span id="L2934" class="LineNr">2934 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L2935" class="LineNr">2935 </span>  <span class="Comment"># position cursor at last line, then try to move further down</span>
<span id="L2936" class="LineNr">2936 </span>  assume-console [
<span id="L2937" class="LineNr">2937 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
<span id="L2938" class="LineNr">2938 </span>    press down-arrow
<span id="L2939" class="LineNr">2939 </span>  ]
<span id="L2940" class="LineNr">2940 </span>  run [
<span id="L2941" class="LineNr">2941 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2942" class="LineNr">2942 </span>  ]
<span id="L2943" class="LineNr">2943 </span>  <span class="Comment"># screen shows partial wrapped line containing a wrap icon</span>
<span id="L2944" class="LineNr">2944 </span>  screen-should-contain [
<span id="L2945" class="LineNr">2945 </span>   <span class="Constant"> .          .</span>
<span id="L2946" class="LineNr">2946 </span>   <span class="Constant"> .efgh↩     .</span>
<span id="L2947" class="LineNr">2947 </span>   <span class="Constant"> .ij        .</span>
<span id="L2948" class="LineNr">2948 </span>   <span class="Constant"> .k         .</span>
<span id="L2949" class="LineNr">2949 </span>  ]
<span id="L2950" class="LineNr">2950 </span>  <span class="Comment"># scroll down again</span>
<span id="L2951" class="LineNr">2951 </span>  assume-console [
<span id="L2952" class="LineNr">2952 </span>    press down-arrow
<span id="L2953" class="LineNr">2953 </span>  ]
<span id="L2954" class="LineNr">2954 </span>  run [
<span id="L2955" class="LineNr">2955 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2956" class="LineNr">2956 </span>  ]
<span id="L2957" class="LineNr">2957 </span>  <span class="Comment"># screen shows partial wrapped line</span>
<span id="L2958" class="LineNr">2958 </span>  screen-should-contain [
<span id="L2959" class="LineNr">2959 </span>   <span class="Constant"> .          .</span>
<span id="L2960" class="LineNr">2960 </span>   <span class="Constant"> .ij        .</span>
<span id="L2961" class="LineNr">2961 </span>   <span class="Constant"> .k         .</span>
<span id="L2962" class="LineNr">2962 </span>   <span class="Constant"> .l         .</span>
<span id="L2963" class="LineNr">2963 </span>  ]
<span id="L2964" class="LineNr">2964 </span>]
<span id="L2965" class="LineNr">2965 </span>
<span id="L2966" class="LineNr">2966 </span><span class="muScenario">scenario</span> editor-scrolls-down-when-line-wraps [
<span id="L2967" class="LineNr">2967 </span>  <span class="Constant">local-scope</span>
<span id="L2968" class="LineNr">2968 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L2969" class="LineNr">2969 </span>  assume-screen <span class="Constant">5/width</span>, <span class="Constant">4/height</span>
<span id="L2970" class="LineNr">2970 </span>  <span class="Comment"># editor contains a long line in the third line</span>
<span id="L2971" class="LineNr">2971 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L2972" class="LineNr">2972 </span><span class="Constant">b</span>
<span id="L2973" class="LineNr">2973 </span><span class="Constant">cdef]</span>
<span id="L2974" class="LineNr">2974 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L2975" class="LineNr">2975 </span>  <span class="Comment"># position cursor at end, type a character</span>
<span id="L2976" class="LineNr">2976 </span>  assume-console [
<span id="L2977" class="LineNr">2977 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 4</span>
<span id="L2978" class="LineNr">2978 </span>    type <span class="Constant">[g]</span>
<span id="L2979" class="LineNr">2979 </span>  ]
<span id="L2980" class="LineNr">2980 </span>  run [
<span id="L2981" class="LineNr">2981 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2982" class="LineNr">2982 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L2983" class="LineNr">2983 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L2984" class="LineNr">2984 </span>  ]
<span id="L2985" class="LineNr">2985 </span>  <span class="Comment"># screen scrolls</span>
<span id="L2986" class="LineNr">2986 </span>  screen-should-contain [
<span id="L2987" class="LineNr">2987 </span>   <span class="Constant"> .     .</span>
<span id="L2988" class="LineNr">2988 </span>   <span class="Constant"> .b    .</span>
<span id="L2989" class="LineNr">2989 </span><span class="Constant">    .cdef↩.</span>
<span id="L2990" class="LineNr">2990 </span>   <span class="Constant"> .g    .</span>
<span id="L2991" class="LineNr">2991 </span>  ]
<span id="L2992" class="LineNr">2992 </span>  memory-should-contain [
<span id="L2993" class="LineNr">2993 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L2994" class="LineNr">2994 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L2995" class="LineNr">2995 </span>  ]
<span id="L2996" class="LineNr">2996 </span>]
<span id="L2997" class="LineNr">2997 </span>
<span id="L2998" class="LineNr">2998 </span><span class="muScenario">scenario</span> editor-stops-scrolling-once-bottom-is-visible [
<span id="L2999" class="LineNr">2999 </span>  <span class="Constant">local-scope</span>
<span id="L3000" class="LineNr">3000 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L3001" class="LineNr">3001 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3002" class="LineNr">3002 </span>  <span class="Comment"># initialize editor with 2 lines</span>
<span id="L3003" class="LineNr">3003 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3004" class="LineNr">3004 </span><span class="Constant">b]</span>
<span id="L3005" class="LineNr">3005 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L3006" class="LineNr">3006 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3007" class="LineNr">3007 </span>  screen-should-contain [
<span id="L3008" class="LineNr">3008 </span>   <span class="Constant"> .          .</span>
<span id="L3009" class="LineNr">3009 </span>   <span class="Constant"> .a         .</span>
<span id="L3010" class="LineNr">3010 </span>   <span class="Constant"> .b         .</span>
<span id="L3011" class="LineNr">3011 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L3012" class="LineNr">3012 </span>  ]
<span id="L3013" class="LineNr">3013 </span>  <span class="Comment"># position cursor at last line, then try to move further down</span>
<span id="L3014" class="LineNr">3014 </span>  assume-console [
<span id="L3015" class="LineNr">3015 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
<span id="L3016" class="LineNr">3016 </span>    press down-arrow
<span id="L3017" class="LineNr">3017 </span>  ]
<span id="L3018" class="LineNr">3018 </span>  run [
<span id="L3019" class="LineNr">3019 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3020" class="LineNr">3020 </span>  ]
<span id="L3021" class="LineNr">3021 </span>  <span class="Comment"># no change since the bottom border was already visible</span>
<span id="L3022" class="LineNr">3022 </span>  screen-should-contain [
<span id="L3023" class="LineNr">3023 </span>   <span class="Constant"> .          .</span>
<span id="L3024" class="LineNr">3024 </span>   <span class="Constant"> .a         .</span>
<span id="L3025" class="LineNr">3025 </span>   <span class="Constant"> .b         .</span>
<span id="L3026" class="LineNr">3026 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L3027" class="LineNr">3027 </span>  ]
<span id="L3028" class="LineNr">3028 </span>]
<span id="L3029" class="LineNr">3029 </span>
<span id="L3030" class="LineNr">3030 </span><span class="muScenario">scenario</span> editor-scrolls-down-on-newline [
<span id="L3031" class="LineNr">3031 </span>  <span class="Constant">local-scope</span>
<span id="L3032" class="LineNr">3032 </span>  assume-screen <span class="Constant">5/width</span>, <span class="Constant">4/height</span>
<span id="L3033" class="LineNr">3033 </span>  <span class="Comment"># position cursor after last line and type newline</span>
<span id="L3034" class="LineNr">3034 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3035" class="LineNr">3035 </span><span class="Constant">b</span>
<span id="L3036" class="LineNr">3036 </span><span class="Constant">c]</span>
<span id="L3037" class="LineNr">3037 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L3038" class="LineNr">3038 </span>  assume-console [
<span id="L3039" class="LineNr">3039 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 4</span>
<span id="L3040" class="LineNr">3040 </span>    type [
<span id="L3041" class="LineNr">3041 </span>]
<span id="L3042" class="LineNr">3042 </span>  ]
<span id="L3043" class="LineNr">3043 </span>  run [
<span id="L3044" class="LineNr">3044 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3045" class="LineNr">3045 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L3046" class="LineNr">3046 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L3047" class="LineNr">3047 </span>  ]
<span id="L3048" class="LineNr">3048 </span>  <span class="Comment"># screen scrolls</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"> .b    .</span>
<span id="L3052" class="LineNr">3052 </span>   <span class="Constant"> .c    .</span>
<span id="L3053" class="LineNr">3053 </span>   <span class="Constant"> .     .</span>
<span id="L3054" class="LineNr">3054 </span>  ]
<span id="L3055" class="LineNr">3055 </span>  memory-should-contain [
<span id="L3056" class="LineNr">3056 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L3057" class="LineNr">3057 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L3058" class="LineNr">3058 </span>  ]
<span id="L3059" class="LineNr">3059 </span>]
<span id="L3060" class="LineNr">3060 </span>
<span id="L3061" class="LineNr">3061 </span><span class="muScenario">scenario</span> editor-scrolls-down-on-right-arrow [
<span id="L3062" class="LineNr">3062 </span>  <span class="Constant">local-scope</span>
<span id="L3063" class="LineNr">3063 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L3064" class="LineNr">3064 </span>  assume-screen <span class="Constant">5/width</span>, <span class="Constant">4/height</span>
<span id="L3065" class="LineNr">3065 </span>  <span class="Comment"># editor contains a wrapped line</span>
<span id="L3066" class="LineNr">3066 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3067" class="LineNr">3067 </span><span class="Constant">b</span>
<span id="L3068" class="LineNr">3068 </span><span class="Constant">cdefgh]</span>
<span id="L3069" class="LineNr">3069 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L3070" class="LineNr">3070 </span>  <span class="Comment"># position cursor at end of screen and try to move right</span>
<span id="L3071" class="LineNr">3071 </span>  assume-console [
<span id="L3072" class="LineNr">3072 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 3</span>
<span id="L3073" class="LineNr">3073 </span>    press right-arrow
<span id="L3074" class="LineNr">3074 </span>  ]
<span id="L3075" class="LineNr">3075 </span>  run [
<span id="L3076" class="LineNr">3076 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3077" class="LineNr">3077 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L3078" class="LineNr">3078 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L3079" class="LineNr">3079 </span>  ]
<span id="L3080" class="LineNr">3080 </span>  <span class="Comment"># screen scrolls</span>
<span id="L3081" class="LineNr">3081 </span>  screen-should-contain [
<span id="L3082" class="LineNr">3082 </span>   <span class="Constant"> .     .</span>
<span id="L3083" class="LineNr">3083 </span>   <span class="Constant"> .b    .</span>
<span id="L3084" class="LineNr">3084 </span><span class="Constant">    .cdef↩.</span>
<span id="L3085" class="LineNr">3085 </span>   <span class="Constant"> .gh   .</span>
<span id="L3086" class="LineNr">3086 </span>  ]
<span id="L3087" class="LineNr">3087 </span>  memory-should-contain [
<span id="L3088" class="LineNr">3088 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L3089" class="LineNr">3089 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L3090" class="LineNr">3090 </span>  ]
<span id="L3091" class="LineNr">3091 </span>]
<span id="L3092" class="LineNr">3092 </span>
<span id="L3093" class="LineNr">3093 </span><span class="muScenario">scenario</span> editor-scrolls-down-on-right-arrow-2 [
<span id="L3094" class="LineNr">3094 </span>  <span class="Constant">local-scope</span>
<span id="L3095" class="LineNr">3095 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L3096" class="LineNr">3096 </span>  assume-screen <span class="Constant">5/width</span>, <span class="Constant">4/height</span>
<span id="L3097" class="LineNr">3097 </span>  <span class="Comment"># editor contains more lines than can fit on screen</span>
<span id="L3098" class="LineNr">3098 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3099" class="LineNr">3099 </span><span class="Constant">b</span>
<span id="L3100" class="LineNr">3100 </span><span class="Constant">c</span>
<span id="L3101" class="LineNr">3101 </span><span class="Constant">d]</span>
<span id="L3102" class="LineNr">3102 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L3103" class="LineNr">3103 </span>  <span class="Comment"># position cursor at end of screen and try to move right</span>
<span id="L3104" class="LineNr">3104 </span>  assume-console [
<span id="L3105" class="LineNr">3105 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 3</span>
<span id="L3106" class="LineNr">3106 </span>    press right-arrow
<span id="L3107" class="LineNr">3107 </span>  ]
<span id="L3108" class="LineNr">3108 </span>  run [
<span id="L3109" class="LineNr">3109 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3110" class="LineNr">3110 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L3111" class="LineNr">3111 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L3112" class="LineNr">3112 </span>  ]
<span id="L3113" class="LineNr">3113 </span>  <span class="Comment"># screen scrolls</span>
<span id="L3114" class="LineNr">3114 </span>  screen-should-contain [
<span id="L3115" class="LineNr">3115 </span>   <span class="Constant"> .     .</span>
<span id="L3116" class="LineNr">3116 </span>   <span class="Constant"> .b    .</span>
<span id="L3117" class="LineNr">3117 </span>   <span class="Constant"> .c    .</span>
<span id="L3118" class="LineNr">3118 </span>   <span class="Constant"> .d    .</span>
<span id="L3119" class="LineNr">3119 </span>  ]
<span id="L3120" class="LineNr">3120 </span>  memory-should-contain [
<span id="L3121" class="LineNr">3121 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L3122" class="LineNr">3122 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L3123" class="LineNr">3123 </span>  ]
<span id="L3124" class="LineNr">3124 </span>]
<span id="L3125" class="LineNr">3125 </span>
<span id="L3126" class="LineNr">3126 </span><span class="muScenario">scenario</span> editor-scrolls-at-end-on-down-arrow [
<span id="L3127" class="LineNr">3127 </span>  <span class="Constant">local-scope</span>
<span id="L3128" class="LineNr">3128 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L3129" class="LineNr">3129 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L3130" class="LineNr">3130 </span><span class="Constant">de]</span>
<span id="L3131" class="LineNr">3131 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L3132" class="LineNr">3132 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3133" class="LineNr">3133 </span>  $clear-trace
<span id="L3134" class="LineNr">3134 </span>  <span class="Comment"># try to move down past end of text</span>
<span id="L3135" class="LineNr">3135 </span>  assume-console [
<span id="L3136" class="LineNr">3136 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
<span id="L3137" class="LineNr">3137 </span>    press down-arrow
<span id="L3138" class="LineNr">3138 </span>  ]
<span id="L3139" class="LineNr">3139 </span>  run [
<span id="L3140" class="LineNr">3140 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3141" class="LineNr">3141 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L3142" class="LineNr">3142 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L3143" class="LineNr">3143 </span>  ]
<span id="L3144" class="LineNr">3144 </span>  <span class="Comment"># no change</span>
<span id="L3145" class="LineNr">3145 </span>  memory-should-contain [
<span id="L3146" class="LineNr">3146 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L3147" class="LineNr">3147 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L3148" class="LineNr">3148 </span>  ]
<span id="L3149" class="LineNr">3149 </span>]
<span id="L3150" class="LineNr">3150 </span>
<span id="L3151" class="LineNr">3151 </span><span class="muScenario">scenario</span> editor-combines-page-and-line-scroll [
<span id="L3152" class="LineNr">3152 </span>  <span class="Constant">local-scope</span>
<span id="L3153" class="LineNr">3153 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L3154" class="LineNr">3154 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3155" class="LineNr">3155 </span>  <span class="Comment"># initialize editor with a few pages of lines</span>
<span id="L3156" class="LineNr">3156 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3157" class="LineNr">3157 </span><span class="Constant">b</span>
<span id="L3158" class="LineNr">3158 </span><span class="Constant">c</span>
<span id="L3159" class="LineNr">3159 </span><span class="Constant">d</span>
<span id="L3160" class="LineNr">3160 </span><span class="Constant">e</span>
<span id="L3161" class="LineNr">3161 </span><span class="Constant">f</span>
<span id="L3162" class="LineNr">3162 </span><span class="Constant">g]</span>
<span id="L3163" class="LineNr">3163 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L3164" class="LineNr">3164 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3165" class="LineNr">3165 </span>  <span class="Comment"># scroll down one page and one line</span>
<span id="L3166" class="LineNr">3166 </span>  assume-console [
<span id="L3167" class="LineNr">3167 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3168" class="LineNr">3168 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
<span id="L3169" class="LineNr">3169 </span>    press down-arrow
<span id="L3170" class="LineNr">3170 </span>  ]
<span id="L3171" class="LineNr">3171 </span>  run [
<span id="L3172" class="LineNr">3172 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3173" class="LineNr">3173 </span>  ]
<span id="L3174" class="LineNr">3174 </span>  <span class="Comment"># screen scrolls down 3 lines</span>
<span id="L3175" class="LineNr">3175 </span>  screen-should-contain [
<span id="L3176" class="LineNr">3176 </span>   <span class="Constant"> .          .</span>
<span id="L3177" class="LineNr">3177 </span>   <span class="Constant"> .d         .</span>
<span id="L3178" class="LineNr">3178 </span>   <span class="Constant"> .e         .</span>
<span id="L3179" class="LineNr">3179 </span>   <span class="Constant"> .f         .</span>
<span id="L3180" class="LineNr">3180 </span>  ]
<span id="L3181" class="LineNr">3181 </span>]
<span id="L3182" class="LineNr">3182 </span>
<span id="L3183" class="LineNr">3183 </span><span class="Comment"># scroll up if necessary</span>
<span id="L3184" class="LineNr">3184 </span>
<span id="L3185" class="LineNr">3185 </span><span class="muScenario">scenario</span> editor-can-scroll-up-using-arrow-keys [
<span id="L3186" class="LineNr">3186 </span>  <span class="Constant">local-scope</span>
<span id="L3187" class="LineNr">3187 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L3188" class="LineNr">3188 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3189" class="LineNr">3189 </span>  <span class="Comment"># initialize editor with &gt;3 lines</span>
<span id="L3190" class="LineNr">3190 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3191" class="LineNr">3191 </span><span class="Constant">b</span>
<span id="L3192" class="LineNr">3192 </span><span class="Constant">c</span>
<span id="L3193" class="LineNr">3193 </span><span class="Constant">d]</span>
<span id="L3194" class="LineNr">3194 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L3195" class="LineNr">3195 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>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"> .a         .</span>
<span id="L3199" class="LineNr">3199 </span>   <span class="Constant"> .b         .</span>
<span id="L3200" class="LineNr">3200 </span>   <span class="Constant"> .c         .</span>
<span id="L3201" class="LineNr">3201 </span>  ]
<span id="L3202" class="LineNr">3202 </span>  <span class="Comment"># position cursor at top of second page, then try to move up</span>
<span id="L3203" class="LineNr">3203 </span>  assume-console [
<span id="L3204" class="LineNr">3204 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3205" class="LineNr">3205 </span>    press up-arrow
<span id="L3206" class="LineNr">3206 </span>  ]
<span id="L3207" class="LineNr">3207 </span>  run [
<span id="L3208" class="LineNr">3208 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3209" class="LineNr">3209 </span>  ]
<span id="L3210" class="LineNr">3210 </span>  <span class="Comment"># screen slides by one line</span>
<span id="L3211" class="LineNr">3211 </span>  screen-should-contain [
<span id="L3212" class="LineNr">3212 </span>   <span class="Constant"> .          .</span>
<span id="L3213" class="LineNr">3213 </span>   <span class="Constant"> .b         .</span>
<span id="L3214" class="LineNr">3214 </span>   <span class="Constant"> .c         .</span>
<span id="L3215" class="LineNr">3215 </span>   <span class="Constant"> .d         .</span>
<span id="L3216" class="LineNr">3216 </span>  ]
<span id="L3217" class="LineNr">3217 </span>]
<span id="L3218" class="LineNr">3218 </span>
<span id="L3219" class="LineNr">3219 </span><span class="muRecipe">after</span> <span class="Constant">&lt;scroll-up&gt;</span> [
<span id="L3220" class="LineNr">3220 </span>  trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[scroll up]</span>
<span id="L3221" class="LineNr">3221 </span>  top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L3222" class="LineNr">3222 </span>  old-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy top-of-screen
<span id="L3223" class="LineNr">3223 </span>  top-of-screen <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1067'>before-previous-screen-line</a> top-of-screen, editor
<span id="L3224" class="LineNr">3224 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top-of-screen
<span id="L3225" class="LineNr">3225 </span>  no-movement?:bool <span class="Special">&lt;-</span> equal old-top, top-of-screen
<span id="L3226" class="LineNr">3226 </span>  <span class="muControl">return-if</span> no-movement?,<span class="Constant"> false/don't-render</span>
<span id="L3227" class="LineNr">3227 </span>]
<span id="L3228" class="LineNr">3228 </span>
<span id="L3229" class="LineNr">3229 </span><span class="muScenario">scenario</span> editor-scrolls-up-past-wrapped-line-using-arrow-keys [
<span id="L3230" class="LineNr">3230 </span>  <span class="Constant">local-scope</span>
<span id="L3231" class="LineNr">3231 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L3232" class="LineNr">3232 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3233" class="LineNr">3233 </span>  <span class="Comment"># initialize editor with a long, wrapped line and more than a screen of</span>
<span id="L3234" class="LineNr">3234 </span>  <span class="Comment"># other lines</span>
<span id="L3235" class="LineNr">3235 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abcdef</span>
<span id="L3236" class="LineNr">3236 </span><span class="Constant">g</span>
<span id="L3237" class="LineNr">3237 </span><span class="Constant">h</span>
<span id="L3238" class="LineNr">3238 </span><span class="Constant">i]</span>
<span id="L3239" class="LineNr">3239 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L3240" class="LineNr">3240 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3241" class="LineNr">3241 </span>  screen-should-contain [
<span id="L3242" class="LineNr">3242 </span>   <span class="Constant"> .          .</span>
<span id="L3243" class="LineNr">3243 </span>   <span class="Constant"> .abcd↩     .</span>
<span id="L3244" class="LineNr">3244 </span>   <span class="Constant"> .ef        .</span>
<span id="L3245" class="LineNr">3245 </span>   <span class="Constant"> .g         .</span>
<span id="L3246" class="LineNr">3246 </span>  ]
<span id="L3247" class="LineNr">3247 </span>  <span class="Comment"># position cursor at top of second page, just below wrapped line</span>
<span id="L3248" class="LineNr">3248 </span>  assume-console [
<span id="L3249" class="LineNr">3249 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3250" class="LineNr">3250 </span>  ]
<span id="L3251" class="LineNr">3251 </span>  run [
<span id="L3252" class="LineNr">3252 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3253" class="LineNr">3253 </span>  ]
<span id="L3254" class="LineNr">3254 </span>  screen-should-contain [
<span id="L3255" class="LineNr">3255 </span>   <span class="Constant"> .          .</span>
<span id="L3256" class="LineNr">3256 </span>   <span class="Constant"> .g         .</span>
<span id="L3257" class="LineNr">3257 </span>   <span class="Constant"> .h         .</span>
<span id="L3258" class="LineNr">3258 </span>   <span class="Constant"> .i         .</span>
<span id="L3259" class="LineNr">3259 </span>  ]
<span id="L3260" class="LineNr">3260 </span>  <span class="Comment"># now move up one line</span>
<span id="L3261" class="LineNr">3261 </span>  assume-console [
<span id="L3262" class="LineNr">3262 </span>    press up-arrow
<span id="L3263" class="LineNr">3263 </span>  ]
<span id="L3264" class="LineNr">3264 </span>  run [
<span id="L3265" class="LineNr">3265 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3266" class="LineNr">3266 </span>  ]
<span id="L3267" class="LineNr">3267 </span>  <span class="Comment"># screen shows partial wrapped line</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"> .ef        .</span>
<span id="L3271" class="LineNr">3271 </span>   <span class="Constant"> .g         .</span>
<span id="L3272" class="LineNr">3272 </span>   <span class="Constant"> .h         .</span>
<span id="L3273" class="LineNr">3273 </span>  ]
<span id="L3274" class="LineNr">3274 </span>]
<span id="L3275" class="LineNr">3275 </span>
<span id="L3276" class="LineNr">3276 </span><span class="muScenario">scenario</span> editor-scrolls-up-past-wrapped-line-using-arrow-keys-2 [
<span id="L3277" class="LineNr">3277 </span>  <span class="Constant">local-scope</span>
<span id="L3278" class="LineNr">3278 </span>  <span class="Comment"># screen has 1 line for menu + 4 lines</span>
<span id="L3279" class="LineNr">3279 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L3280" class="LineNr">3280 </span>  <span class="Comment"># editor starts with a long line wrapping twice, occupying 3 of the 4 lines</span>
<span id="L3281" class="LineNr">3281 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abcdefghij</span>
<span id="L3282" class="LineNr">3282 </span><span class="Constant">k</span>
<span id="L3283" class="LineNr">3283 </span><span class="Constant">l</span>
<span id="L3284" class="LineNr">3284 </span><span class="Constant">m]</span>
<span id="L3285" class="LineNr">3285 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L3286" class="LineNr">3286 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3287" class="LineNr">3287 </span>  <span class="Comment"># position cursor at top of second page</span>
<span id="L3288" class="LineNr">3288 </span>  assume-console [
<span id="L3289" class="LineNr">3289 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3290" class="LineNr">3290 </span>  ]
<span id="L3291" class="LineNr">3291 </span>  run [
<span id="L3292" class="LineNr">3292 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3293" class="LineNr">3293 </span>  ]
<span id="L3294" class="LineNr">3294 </span>  screen-should-contain [
<span id="L3295" class="LineNr">3295 </span>   <span class="Constant"> .          .</span>
<span id="L3296" class="LineNr">3296 </span>   <span class="Constant"> .k         .</span>
<span id="L3297" class="LineNr">3297 </span>   <span class="Constant"> .l         .</span>
<span id="L3298" class="LineNr">3298 </span>   <span class="Constant"> .m         .</span>
<span id="L3299" class="LineNr">3299 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L3300" class="LineNr">3300 </span>  ]
<span id="L3301" class="LineNr">3301 </span>  <span class="Comment"># move up one line</span>
<span id="L3302" class="LineNr">3302 </span>  assume-console [
<span id="L3303" class="LineNr">3303 </span>    press up-arrow
<span id="L3304" class="LineNr">3304 </span>  ]
<span id="L3305" class="LineNr">3305 </span>  run [
<span id="L3306" class="LineNr">3306 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3307" class="LineNr">3307 </span>  ]
<span id="L3308" class="LineNr">3308 </span>  <span class="Comment"># screen shows partial wrapped line</span>
<span id="L3309" class="LineNr">3309 </span>  screen-should-contain [
<span id="L3310" class="LineNr">3310 </span>   <span class="Constant"> .          .</span>
<span id="L3311" class="LineNr">3311 </span>   <span class="Constant"> .ij        .</span>
<span id="L3312" class="LineNr">3312 </span>   <span class="Constant"> .k         .</span>
<span id="L3313" class="LineNr">3313 </span>   <span class="Constant"> .l         .</span>
<span id="L3314" class="LineNr">3314 </span>   <span class="Constant"> .m         .</span>
<span id="L3315" class="LineNr">3315 </span>  ]
<span id="L3316" class="LineNr">3316 </span>  <span class="Comment"># move up a second line</span>
<span id="L3317" class="LineNr">3317 </span>  assume-console [
<span id="L3318" class="LineNr">3318 </span>    press up-arrow
<span id="L3319" class="LineNr">3319 </span>  ]
<span id="L3320" class="LineNr">3320 </span>  run [
<span id="L3321" class="LineNr">3321 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3322" class="LineNr">3322 </span>  ]
<span id="L3323" class="LineNr">3323 </span>  <span class="Comment"># screen shows partial wrapped line</span>
<span id="L3324" class="LineNr">3324 </span>  screen-should-contain [
<span id="L3325" class="LineNr">3325 </span>   <span class="Constant"> .          .</span>
<span id="L3326" class="LineNr">3326 </span>   <span class="Constant"> .efgh↩     .</span>
<span id="L3327" class="LineNr">3327 </span>   <span class="Constant"> .ij        .</span>
<span id="L3328" class="LineNr">3328 </span>   <span class="Constant"> .k         .</span>
<span id="L3329" class="LineNr">3329 </span>   <span class="Constant"> .l         .</span>
<span id="L3330" class="LineNr">3330 </span>  ]
<span id="L3331" class="LineNr">3331 </span>  <span class="Comment"># move up a third line</span>
<span id="L3332" class="LineNr">3332 </span>  assume-console [
<span id="L3333" class="LineNr">3333 </span>    press up-arrow
<span id="L3334" class="LineNr">3334 </span>  ]
<span id="L3335" class="LineNr">3335 </span>  run [
<span id="L3336" class="LineNr">3336 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3337" class="LineNr">3337 </span>  ]
<span id="L3338" class="LineNr">3338 </span>  <span class="Comment"># screen shows partial wrapped line</span>
<span id="L3339" class="LineNr">3339 </span>  screen-should-contain [
<span id="L3340" class="LineNr">3340 </span>   <span class="Constant"> .          .</span>
<span id="L3341" class="LineNr">3341 </span>   <span class="Constant"> .abcd↩     .</span>
<span id="L3342" class="LineNr">3342 </span>   <span class="Constant"> .efgh↩     .</span>
<span id="L3343" class="LineNr">3343 </span>   <span class="Constant"> .ij        .</span>
<span id="L3344" class="LineNr">3344 </span>   <span class="Constant"> .k         .</span>
<span id="L3345" class="LineNr">3345 </span>  ]
<span id="L3346" class="LineNr">3346 </span>]
<span id="L3347" class="LineNr">3347 </span>
<span id="L3348" class="LineNr">3348 </span><span class="Comment"># same as editor-scrolls-up-past-wrapped-line-using-arrow-keys but length</span>
<span id="L3349" class="LineNr">3349 </span><span class="Comment"># slightly off, just to prevent over-training</span>
<span id="L3350" class="LineNr">3350 </span><span class="muScenario">scenario</span> editor-scrolls-up-past-wrapped-line-using-arrow-keys-3 [
<span id="L3351" class="LineNr">3351 </span>  <span class="Constant">local-scope</span>
<span id="L3352" class="LineNr">3352 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L3353" class="LineNr">3353 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3354" class="LineNr">3354 </span>  <span class="Comment"># initialize editor with a long, wrapped line and more than a screen of</span>
<span id="L3355" class="LineNr">3355 </span>  <span class="Comment"># other lines</span>
<span id="L3356" class="LineNr">3356 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abcdef</span>
<span id="L3357" class="LineNr">3357 </span><span class="Constant">g</span>
<span id="L3358" class="LineNr">3358 </span><span class="Constant">h</span>
<span id="L3359" class="LineNr">3359 </span><span class="Constant">i]</span>
<span id="L3360" class="LineNr">3360 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">6/right</span>
<span id="L3361" class="LineNr">3361 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3362" class="LineNr">3362 </span>  screen-should-contain [
<span id="L3363" class="LineNr">3363 </span>   <span class="Constant"> .          .</span>
<span id="L3364" class="LineNr">3364 </span>   <span class="Constant"> .abcde↩    .</span>
<span id="L3365" class="LineNr">3365 </span>   <span class="Constant"> .f         .</span>
<span id="L3366" class="LineNr">3366 </span>   <span class="Constant"> .g         .</span>
<span id="L3367" class="LineNr">3367 </span>  ]
<span id="L3368" class="LineNr">3368 </span>  <span class="Comment"># position cursor at top of second page, just below wrapped line</span>
<span id="L3369" class="LineNr">3369 </span>  assume-console [
<span id="L3370" class="LineNr">3370 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3371" class="LineNr">3371 </span>  ]
<span id="L3372" class="LineNr">3372 </span>  run [
<span id="L3373" class="LineNr">3373 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3374" class="LineNr">3374 </span>  ]
<span id="L3375" class="LineNr">3375 </span>  screen-should-contain [
<span id="L3376" class="LineNr">3376 </span>   <span class="Constant"> .          .</span>
<span id="L3377" class="LineNr">3377 </span>   <span class="Constant"> .g         .</span>
<span id="L3378" class="LineNr">3378 </span>   <span class="Constant"> .h         .</span>
<span id="L3379" class="LineNr">3379 </span>   <span class="Constant"> .i         .</span>
<span id="L3380" class="LineNr">3380 </span>  ]
<span id="L3381" class="LineNr">3381 </span>  <span class="Comment"># now move up one line</span>
<span id="L3382" class="LineNr">3382 </span>  assume-console [
<span id="L3383" class="LineNr">3383 </span>    press up-arrow
<span id="L3384" class="LineNr">3384 </span>  ]
<span id="L3385" class="LineNr">3385 </span>  run [
<span id="L3386" class="LineNr">3386 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3387" class="LineNr">3387 </span>  ]
<span id="L3388" class="LineNr">3388 </span>  <span class="Comment"># screen shows partial wrapped line</span>
<span id="L3389" class="LineNr">3389 </span>  screen-should-contain [
<span id="L3390" class="LineNr">3390 </span>   <span class="Constant"> .          .</span>
<span id="L3391" class="LineNr">3391 </span>   <span class="Constant"> .f         .</span>
<span id="L3392" class="LineNr">3392 </span>   <span class="Constant"> .g         .</span>
<span id="L3393" class="LineNr">3393 </span>   <span class="Constant"> .h         .</span>
<span id="L3394" class="LineNr">3394 </span>  ]
<span id="L3395" class="LineNr">3395 </span>]
<span id="L3396" class="LineNr">3396 </span>
<span id="L3397" class="LineNr">3397 </span><span class="Comment"># check empty lines</span>
<span id="L3398" class="LineNr">3398 </span><span class="muScenario">scenario</span> editor-scrolls-up-past-wrapped-line-using-arrow-keys-4 [
<span id="L3399" class="LineNr">3399 </span>  <span class="Constant">local-scope</span>
<span id="L3400" class="LineNr">3400 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3401" class="LineNr">3401 </span>  <span class="Comment"># initialize editor with some lines around an empty line</span>
<span id="L3402" class="LineNr">3402 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3403" class="LineNr">3403 </span><span class="Constant">b</span>
<span id="L3404" class="LineNr">3404 </span>
<span id="L3405" class="LineNr">3405 </span>c
<span id="L3406" class="LineNr">3406 </span>d
<span id="L3407" class="LineNr">3407 </span>e]
<span id="L3408" class="LineNr">3408 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">6/right</span>
<span id="L3409" class="LineNr">3409 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3410" class="LineNr">3410 </span>  assume-console [
<span id="L3411" class="LineNr">3411 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3412" class="LineNr">3412 </span>  ]
<span id="L3413" class="LineNr">3413 </span>  run [
<span id="L3414" class="LineNr">3414 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3415" class="LineNr">3415 </span>  ]
<span id="L3416" class="LineNr">3416 </span>  screen-should-contain [
<span id="L3417" class="LineNr">3417 </span>   <span class="Constant"> .          .</span>
<span id="L3418" class="LineNr">3418 </span>   <span class="Constant"> .          .</span>
<span id="L3419" class="LineNr">3419 </span>   <span class="Constant"> .c         .</span>
<span id="L3420" class="LineNr">3420 </span>   <span class="Constant"> .d         .</span>
<span id="L3421" class="LineNr">3421 </span>  ]
<span id="L3422" class="LineNr">3422 </span>  assume-console [
<span id="L3423" class="LineNr">3423 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3424" class="LineNr">3424 </span>  ]
<span id="L3425" class="LineNr">3425 </span>  run [
<span id="L3426" class="LineNr">3426 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3427" class="LineNr">3427 </span>  ]
<span id="L3428" class="LineNr">3428 </span>  screen-should-contain [
<span id="L3429" class="LineNr">3429 </span>   <span class="Constant"> .          .</span>
<span id="L3430" class="LineNr">3430 </span>   <span class="Constant"> .d         .</span>
<span id="L3431" class="LineNr">3431 </span>   <span class="Constant"> .e         .</span>
<span id="L3432" class="LineNr">3432 </span>   <span class="Constant"> .╌╌╌╌╌╌    .</span>
<span id="L3433" class="LineNr">3433 </span>  ]
<span id="L3434" class="LineNr">3434 </span>  assume-console [
<span id="L3435" class="LineNr">3435 </span>    press <a href='003-shortcuts.mu.html#L3833'>page-up</a>
<span id="L3436" class="LineNr">3436 </span>  ]
<span id="L3437" class="LineNr">3437 </span>  run [
<span id="L3438" class="LineNr">3438 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3439" class="LineNr">3439 </span>  ]
<span id="L3440" class="LineNr">3440 </span>  screen-should-contain [
<span id="L3441" class="LineNr">3441 </span>   <span class="Constant"> .          .</span>
<span id="L3442" class="LineNr">3442 </span>   <span class="Constant"> .          .</span>
<span id="L3443" class="LineNr">3443 </span>   <span class="Constant"> .c         .</span>
<span id="L3444" class="LineNr">3444 </span>   <span class="Constant"> .d         .</span>
<span id="L3445" class="LineNr">3445 </span>  ]
<span id="L3446" class="LineNr">3446 </span>]
<span id="L3447" class="LineNr">3447 </span>
<span id="L3448" class="LineNr">3448 </span><span class="muScenario">scenario</span> editor-scrolls-up-on-left-arrow [
<span id="L3449" class="LineNr">3449 </span>  <span class="Constant">local-scope</span>
<span id="L3450" class="LineNr">3450 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L3451" class="LineNr">3451 </span>  assume-screen <span class="Constant">5/width</span>, <span class="Constant">4/height</span>
<span id="L3452" class="LineNr">3452 </span>  <span class="Comment"># editor contains &gt;3 lines</span>
<span id="L3453" class="LineNr">3453 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3454" class="LineNr">3454 </span><span class="Constant">b</span>
<span id="L3455" class="LineNr">3455 </span><span class="Constant">c</span>
<span id="L3456" class="LineNr">3456 </span><span class="Constant">d</span>
<span id="L3457" class="LineNr">3457 </span><span class="Constant">e]</span>
<span id="L3458" class="LineNr">3458 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L3459" class="LineNr">3459 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3460" class="LineNr">3460 </span>  <span class="Comment"># position cursor at top of second page</span>
<span id="L3461" class="LineNr">3461 </span>  assume-console [
<span id="L3462" class="LineNr">3462 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3463" class="LineNr">3463 </span>  ]
<span id="L3464" class="LineNr">3464 </span>  run [
<span id="L3465" class="LineNr">3465 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3466" class="LineNr">3466 </span>  ]
<span id="L3467" class="LineNr">3467 </span>  screen-should-contain [
<span id="L3468" class="LineNr">3468 </span>   <span class="Constant"> .     .</span>
<span id="L3469" class="LineNr">3469 </span>   <span class="Constant"> .c    .</span>
<span id="L3470" class="LineNr">3470 </span>   <span class="Constant"> .d    .</span>
<span id="L3471" class="LineNr">3471 </span>   <span class="Constant"> .e    .</span>
<span id="L3472" class="LineNr">3472 </span>  ]
<span id="L3473" class="LineNr">3473 </span>  <span class="Comment"># now try to move left</span>
<span id="L3474" class="LineNr">3474 </span>  assume-console [
<span id="L3475" class="LineNr">3475 </span>    press left-arrow
<span id="L3476" class="LineNr">3476 </span>  ]
<span id="L3477" class="LineNr">3477 </span>  run [
<span id="L3478" class="LineNr">3478 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3479" class="LineNr">3479 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L3480" class="LineNr">3480 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L3481" class="LineNr">3481 </span>  ]
<span id="L3482" class="LineNr">3482 </span>  <span class="Comment"># screen scrolls</span>
<span id="L3483" class="LineNr">3483 </span>  screen-should-contain [
<span id="L3484" class="LineNr">3484 </span>   <span class="Constant"> .     .</span>
<span id="L3485" class="LineNr">3485 </span>   <span class="Constant"> .b    .</span>
<span id="L3486" class="LineNr">3486 </span>   <span class="Constant"> .c    .</span>
<span id="L3487" class="LineNr">3487 </span>   <span class="Constant"> .d    .</span>
<span id="L3488" class="LineNr">3488 </span>  ]
<span id="L3489" class="LineNr">3489 </span>  memory-should-contain [
<span id="L3490" class="LineNr">3490 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L3491" class="LineNr">3491 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L3492" class="LineNr">3492 </span>  ]
<span id="L3493" class="LineNr">3493 </span>]
<span id="L3494" class="LineNr">3494 </span>
<span id="L3495" class="LineNr">3495 </span><span class="muScenario">scenario</span> editor-can-scroll-up-to-start-of-file [
<span id="L3496" class="LineNr">3496 </span>  <span class="Constant">local-scope</span>
<span id="L3497" class="LineNr">3497 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L3498" class="LineNr">3498 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3499" class="LineNr">3499 </span>  <span class="Comment"># initialize editor with &gt;3 lines</span>
<span id="L3500" class="LineNr">3500 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3501" class="LineNr">3501 </span><span class="Constant">b</span>
<span id="L3502" class="LineNr">3502 </span><span class="Constant">c</span>
<span id="L3503" class="LineNr">3503 </span><span class="Constant">d]</span>
<span id="L3504" class="LineNr">3504 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L3505" class="LineNr">3505 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3506" class="LineNr">3506 </span>  screen-should-contain [
<span id="L3507" class="LineNr">3507 </span>   <span class="Constant"> .          .</span>
<span id="L3508" class="LineNr">3508 </span>   <span class="Constant"> .a         .</span>
<span id="L3509" class="LineNr">3509 </span>   <span class="Constant"> .b         .</span>
<span id="L3510" class="LineNr">3510 </span>   <span class="Constant"> .c         .</span>
<span id="L3511" class="LineNr">3511 </span>  ]
<span id="L3512" class="LineNr">3512 </span>  <span class="Comment"># position cursor at top of second page, then try to move up to start of</span>
<span id="L3513" class="LineNr">3513 </span>  <span class="Comment"># text</span>
<span id="L3514" class="LineNr">3514 </span>  assume-console [
<span id="L3515" class="LineNr">3515 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3516" class="LineNr">3516 </span>    press up-arrow
<span id="L3517" class="LineNr">3517 </span>    press up-arrow
<span id="L3518" class="LineNr">3518 </span>  ]
<span id="L3519" class="LineNr">3519 </span>  run [
<span id="L3520" class="LineNr">3520 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3521" class="LineNr">3521 </span>  ]
<span id="L3522" class="LineNr">3522 </span>  <span class="Comment"># screen slides by one line</span>
<span id="L3523" class="LineNr">3523 </span>  screen-should-contain [
<span id="L3524" class="LineNr">3524 </span>   <span class="Constant"> .          .</span>
<span id="L3525" class="LineNr">3525 </span>   <span class="Constant"> .a         .</span>
<span id="L3526" class="LineNr">3526 </span>   <span class="Constant"> .b         .</span>
<span id="L3527" class="LineNr">3527 </span>   <span class="Constant"> .c         .</span>
<span id="L3528" class="LineNr">3528 </span>  ]
<span id="L3529" class="LineNr">3529 </span>  <span class="Comment"># try to move up again</span>
<span id="L3530" class="LineNr">3530 </span>  assume-console [
<span id="L3531" class="LineNr">3531 </span>    press up-arrow
<span id="L3532" class="LineNr">3532 </span>  ]
<span id="L3533" class="LineNr">3533 </span>  run [
<span id="L3534" class="LineNr">3534 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3535" class="LineNr">3535 </span>  ]
<span id="L3536" class="LineNr">3536 </span>  <span class="Comment"># screen remains unchanged</span>
<span id="L3537" class="LineNr">3537 </span>  screen-should-contain [
<span id="L3538" class="LineNr">3538 </span>   <span class="Constant"> .          .</span>
<span id="L3539" class="LineNr">3539 </span>   <span class="Constant"> .a         .</span>
<span id="L3540" class="LineNr">3540 </span>   <span class="Constant"> .b         .</span>
<span id="L3541" class="LineNr">3541 </span>   <span class="Constant"> .c         .</span>
<span id="L3542" class="LineNr">3542 </span>  ]
<span id="L3543" class="LineNr">3543 </span>]
<span id="L3544" class="LineNr">3544 </span>
<span id="L3545" class="LineNr">3545 </span><span class="Comment"># ctrl-f/page-down - render next page if it exists</span>
<span id="L3546" class="LineNr">3546 </span>
<span id="L3547" class="LineNr">3547 </span><span class="muScenario">scenario</span> editor-can-scroll [
<span id="L3548" class="LineNr">3548 </span>  <span class="Constant">local-scope</span>
<span id="L3549" class="LineNr">3549 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3550" class="LineNr">3550 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3551" class="LineNr">3551 </span><span class="Constant">b</span>
<span id="L3552" class="LineNr">3552 </span><span class="Constant">c</span>
<span id="L3553" class="LineNr">3553 </span><span class="Constant">d]</span>
<span id="L3554" class="LineNr">3554 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L3555" class="LineNr">3555 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3556" class="LineNr">3556 </span>  screen-should-contain [
<span id="L3557" class="LineNr">3557 </span>   <span class="Constant"> .          .</span>
<span id="L3558" class="LineNr">3558 </span>   <span class="Constant"> .a         .</span>
<span id="L3559" class="LineNr">3559 </span>   <span class="Constant"> .b         .</span>
<span id="L3560" class="LineNr">3560 </span>   <span class="Constant"> .c         .</span>
<span id="L3561" class="LineNr">3561 </span>  ]
<span id="L3562" class="LineNr">3562 </span>  <span class="Comment"># scroll down</span>
<span id="L3563" class="LineNr">3563 </span>  assume-console [
<span id="L3564" class="LineNr">3564 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3565" class="LineNr">3565 </span>  ]
<span id="L3566" class="LineNr">3566 </span>  run [
<span id="L3567" class="LineNr">3567 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3568" class="LineNr">3568 </span>  ]
<span id="L3569" class="LineNr">3569 </span>  <span class="Comment"># screen shows next page</span>
<span id="L3570" class="LineNr">3570 </span>  screen-should-contain [
<span id="L3571" class="LineNr">3571 </span>   <span class="Constant"> .          .</span>
<span id="L3572" class="LineNr">3572 </span>   <span class="Constant"> .c         .</span>
<span id="L3573" class="LineNr">3573 </span>   <span class="Constant"> .d         .</span>
<span id="L3574" class="LineNr">3574 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L3575" class="LineNr">3575 </span>  ]
<span id="L3576" class="LineNr">3576 </span>]
<span id="L3577" class="LineNr">3577 </span>
<span id="L3578" class="LineNr">3578 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L3579" class="LineNr">3579 </span>  <span class="Delimiter">{</span>
<span id="L3580" class="LineNr">3580 </span>    page-down?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">6/ctrl-f</span>
<span id="L3581" class="LineNr">3581 </span>    <span class="muControl">break-unless</span> page-down?
<span id="L3582" class="LineNr">3582 </span>    old-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L3583" class="LineNr">3583 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L3584" class="LineNr">3584 </span>    <a href='003-shortcuts.mu.html#L3610'>page-down</a> editor
<span id="L3585" class="LineNr">3585 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
<span id="L3586" class="LineNr">3586 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L3587" class="LineNr">3587 </span>    top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L3588" class="LineNr">3588 </span>    movement?:bool <span class="Special">&lt;-</span> not-equal top-of-screen, old-top
<span id="L3589" class="LineNr">3589 </span>   <span class="muControl"> return</span> movement?/go-render
<span id="L3590" class="LineNr">3590 </span>  <span class="Delimiter">}</span>
<span id="L3591" class="LineNr">3591 </span>]
<span id="L3592" class="LineNr">3592 </span>
<span id="L3593" class="LineNr">3593 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L199'>&lt;handle-special-key&gt;</a></span> [
<span id="L3594" class="LineNr">3594 </span>  <span class="Delimiter">{</span>
<span id="L3595" class="LineNr">3595 </span>    page-down?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65518/page-down</span>
<span id="L3596" class="LineNr">3596 </span>    <span class="muControl">break-unless</span> page-down?
<span id="L3597" class="LineNr">3597 </span>    old-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L3598" class="LineNr">3598 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L3599" class="LineNr">3599 </span>    <a href='003-shortcuts.mu.html#L3610'>page-down</a> editor
<span id="L3600" class="LineNr">3600 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
<span id="L3601" class="LineNr">3601 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L3602" class="LineNr">3602 </span>    top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L3603" class="LineNr">3603 </span>    movement?:bool <span class="Special">&lt;-</span> not-equal top-of-screen, old-top
<span id="L3604" class="LineNr">3604 </span>   <span class="muControl"> return</span> movement?/go-render
<span id="L3605" class="LineNr">3605 </span>  <span class="Delimiter">}</span>
<span id="L3606" class="LineNr">3606 </span>]
<span id="L3607" class="LineNr">3607 </span>
<span id="L3608" class="LineNr">3608 </span><span class="Comment"># page-down skips entire wrapped lines, so it can't scroll past lines</span>
<span id="L3609" class="LineNr">3609 </span><span class="Comment"># taking up the entire screen</span>
<span id="L3610" class="LineNr">3610 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L3610'>page-down</a> editor:&amp;:editor<span class="muRecipe"> -&gt; </span>editor:&amp;:editor [
<span id="L3611" class="LineNr">3611 </span>  <span class="Constant">local-scope</span>
<span id="L3612" class="LineNr">3612 </span>  <span class="Constant">load-inputs</span>
<span id="L3613" class="LineNr">3613 </span>  <span class="Comment"># if editor contents don't overflow screen, do nothing</span>
<span id="L3614" class="LineNr">3614 </span>  bottom-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">bottom-of-screen:offset</span>
<span id="L3615" class="LineNr">3615 </span>  <span class="muControl">return-unless</span> bottom-of-screen
<span id="L3616" class="LineNr">3616 </span>  <span class="Comment"># if not, position cursor at final character</span>
<span id="L3617" class="LineNr">3617 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L3618" class="LineNr">3618 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L38'>prev</a> bottom-of-screen
<span id="L3619" class="LineNr">3619 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L3620" class="LineNr">3620 </span>  <span class="Comment"># keep one line in common with previous page</span>
<span id="L3621" class="LineNr">3621 </span>  <span class="Delimiter">{</span>
<span id="L3622" class="LineNr">3622 </span>    <a href='../065duplex_list.mu.html#L629'>last</a>:char <span class="Special">&lt;-</span> get *before-cursor, <span class="Constant">value:offset</span>
<span id="L3623" class="LineNr">3623 </span>    newline?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L629'>last</a>, <span class="Constant">10/newline</span>
<span id="L3624" class="LineNr">3624 </span>    <span class="muControl">break-unless</span> newline?:bool
<span id="L3625" class="LineNr">3625 </span>    before-cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L38'>prev</a> before-cursor
<span id="L3626" class="LineNr">3626 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L3627" class="LineNr">3627 </span>  <span class="Delimiter">}</span>
<span id="L3628" class="LineNr">3628 </span>  <span class="Comment"># move cursor and top-of-screen to start of that line</span>
<span id="L3629" class="LineNr">3629 </span>  <a href='003-shortcuts.mu.html#L3635'>move-to-start-of-line</a> editor
<span id="L3630" class="LineNr">3630 </span>  before-cursor <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L3631" class="LineNr">3631 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, before-cursor
<span id="L3632" class="LineNr">3632 </span>]
<span id="L3633" class="LineNr">3633 </span>
<span id="L3634" class="LineNr">3634 </span><span class="Comment"># jump to previous newline</span>
<span id="L3635" class="LineNr">3635 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L3635'>move-to-start-of-line</a> editor:&amp;:editor<span class="muRecipe"> -&gt; </span>editor:&amp;:editor [
<span id="L3636" class="LineNr">3636 </span>  <span class="Constant">local-scope</span>
<span id="L3637" class="LineNr">3637 </span>  <span class="Constant">load-inputs</span>
<span id="L3638" class="LineNr">3638 </span>  <span class="Comment"># update cursor column</span>
<span id="L3639" class="LineNr">3639 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L3640" class="LineNr">3640 </span>  cursor-column:num <span class="Special">&lt;-</span> copy left
<span id="L3641" class="LineNr">3641 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L3642" class="LineNr">3642 </span>  <span class="Comment"># update before-cursor</span>
<span id="L3643" class="LineNr">3643 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L3644" class="LineNr">3644 </span>  init:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
<span id="L3645" class="LineNr">3645 </span>  <span class="Comment"># while not at start of line, move</span>
<span id="L3646" class="LineNr">3646 </span>  <span class="Delimiter">{</span>
<span id="L3647" class="LineNr">3647 </span>    at-start-of-text?:bool <span class="Special">&lt;-</span> equal before-cursor, init
<span id="L3648" class="LineNr">3648 </span>    <span class="muControl">break-if</span> at-start-of-text?
<span id="L3649" class="LineNr">3649 </span>    <a href='../065duplex_list.mu.html#L38'>prev</a>:char <span class="Special">&lt;-</span> get *before-cursor, <span class="Constant">value:offset</span>
<span id="L3650" class="LineNr">3650 </span>    at-start-of-line?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L38'>prev</a>, <span class="Constant">10/newline</span>
<span id="L3651" class="LineNr">3651 </span>    <span class="muControl">break-if</span> at-start-of-line?
<span id="L3652" class="LineNr">3652 </span>    before-cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L38'>prev</a> before-cursor
<span id="L3653" class="LineNr">3653 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L3654" class="LineNr">3654 </span>    assert before-cursor, <span class="Constant">[move-to-start-of-line tried to move before start of text]</span>
<span id="L3655" class="LineNr">3655 </span>   <span class="muControl"> loop</span>
<span id="L3656" class="LineNr">3656 </span>  <span class="Delimiter">}</span>
<span id="L3657" class="LineNr">3657 </span>]
<span id="L3658" class="LineNr">3658 </span>
<span id="L3659" class="LineNr">3659 </span><span class="muScenario">scenario</span> editor-does-not-scroll-past-end [
<span id="L3660" class="LineNr">3660 </span>  <span class="Constant">local-scope</span>
<span id="L3661" class="LineNr">3661 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3662" class="LineNr">3662 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3663" class="LineNr">3663 </span><span class="Constant">b]</span>
<span id="L3664" class="LineNr">3664 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L3665" class="LineNr">3665 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3666" class="LineNr">3666 </span>  screen-should-contain [
<span id="L3667" class="LineNr">3667 </span>   <span class="Constant"> .          .</span>
<span id="L3668" class="LineNr">3668 </span>   <span class="Constant"> .a         .</span>
<span id="L3669" class="LineNr">3669 </span>   <span class="Constant"> .b         .</span>
<span id="L3670" class="LineNr">3670 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L3671" class="LineNr">3671 </span>  ]
<span id="L3672" class="LineNr">3672 </span>  <span class="Comment"># scroll down</span>
<span id="L3673" class="LineNr">3673 </span>  assume-console [
<span id="L3674" class="LineNr">3674 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3675" class="LineNr">3675 </span>  ]
<span id="L3676" class="LineNr">3676 </span>  run [
<span id="L3677" class="LineNr">3677 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3678" class="LineNr">3678 </span>  ]
<span id="L3679" class="LineNr">3679 </span>  <span class="Comment"># screen remains unmodified</span>
<span id="L3680" class="LineNr">3680 </span>  screen-should-contain [
<span id="L3681" class="LineNr">3681 </span>   <span class="Constant"> .          .</span>
<span id="L3682" class="LineNr">3682 </span>   <span class="Constant"> .a         .</span>
<span id="L3683" class="LineNr">3683 </span>   <span class="Constant"> .b         .</span>
<span id="L3684" class="LineNr">3684 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L3685" class="LineNr">3685 </span>  ]
<span id="L3686" class="LineNr">3686 </span>]
<span id="L3687" class="LineNr">3687 </span>
<span id="L3688" class="LineNr">3688 </span><span class="muScenario">scenario</span> editor-starts-next-page-at-start-of-wrapped-line [
<span id="L3689" class="LineNr">3689 </span>  <span class="Constant">local-scope</span>
<span id="L3690" class="LineNr">3690 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines for text</span>
<span id="L3691" class="LineNr">3691 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3692" class="LineNr">3692 </span>  <span class="Comment"># editor contains a long last line</span>
<span id="L3693" class="LineNr">3693 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3694" class="LineNr">3694 </span><span class="Constant">b</span>
<span id="L3695" class="LineNr">3695 </span><span class="Constant">cdefgh]</span>
<span id="L3696" class="LineNr">3696 </span>  <span class="Comment"># editor screen triggers wrap of last line</span>
<span id="L3697" class="LineNr">3697 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">4/right</span>
<span id="L3698" class="LineNr">3698 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3699" class="LineNr">3699 </span>  <span class="Comment"># some part of last line is not displayed</span>
<span id="L3700" class="LineNr">3700 </span>  screen-should-contain [
<span id="L3701" class="LineNr">3701 </span>   <span class="Constant"> .          .</span>
<span id="L3702" class="LineNr">3702 </span>   <span class="Constant"> .a         .</span>
<span id="L3703" class="LineNr">3703 </span>   <span class="Constant"> .b         .</span>
<span id="L3704" class="LineNr">3704 </span>   <span class="Constant"> .cde↩      .</span>
<span id="L3705" class="LineNr">3705 </span>  ]
<span id="L3706" class="LineNr">3706 </span>  <span class="Comment"># scroll down</span>
<span id="L3707" class="LineNr">3707 </span>  assume-console [
<span id="L3708" class="LineNr">3708 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3709" class="LineNr">3709 </span>  ]
<span id="L3710" class="LineNr">3710 </span>  run [
<span id="L3711" class="LineNr">3711 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3712" class="LineNr">3712 </span>  ]
<span id="L3713" class="LineNr">3713 </span>  <span class="Comment"># screen shows entire wrapped line</span>
<span id="L3714" class="LineNr">3714 </span>  screen-should-contain [
<span id="L3715" class="LineNr">3715 </span>   <span class="Constant"> .          .</span>
<span id="L3716" class="LineNr">3716 </span>   <span class="Constant"> .cde↩      .</span>
<span id="L3717" class="LineNr">3717 </span>   <span class="Constant"> .fgh       .</span>
<span id="L3718" class="LineNr">3718 </span>   <span class="Constant"> .╌╌╌╌      .</span>
<span id="L3719" class="LineNr">3719 </span>  ]
<span id="L3720" class="LineNr">3720 </span>]
<span id="L3721" class="LineNr">3721 </span>
<span id="L3722" class="LineNr">3722 </span><span class="muScenario">scenario</span> editor-starts-next-page-at-start-of-wrapped-line-2 [
<span id="L3723" class="LineNr">3723 </span>  <span class="Constant">local-scope</span>
<span id="L3724" class="LineNr">3724 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines for text</span>
<span id="L3725" class="LineNr">3725 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3726" class="LineNr">3726 </span>  <span class="Comment"># editor contains a very long line that occupies last two lines of screen</span>
<span id="L3727" class="LineNr">3727 </span>  <span class="Comment"># and still has something left over</span>
<span id="L3728" class="LineNr">3728 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3729" class="LineNr">3729 </span><span class="Constant">bcdefgh]</span>
<span id="L3730" class="LineNr">3730 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">4/right</span>
<span id="L3731" class="LineNr">3731 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3732" class="LineNr">3732 </span>  <span class="Comment"># some part of last line is not displayed</span>
<span id="L3733" class="LineNr">3733 </span>  screen-should-contain [
<span id="L3734" class="LineNr">3734 </span>   <span class="Constant"> .          .</span>
<span id="L3735" class="LineNr">3735 </span>   <span class="Constant"> .a         .</span>
<span id="L3736" class="LineNr">3736 </span>   <span class="Constant"> .bcd↩      .</span>
<span id="L3737" class="LineNr">3737 </span>   <span class="Constant"> .efg↩      .</span>
<span id="L3738" class="LineNr">3738 </span>  ]
<span id="L3739" class="LineNr">3739 </span>  <span class="Comment"># scroll down</span>
<span id="L3740" class="LineNr">3740 </span>  assume-console [
<span id="L3741" class="LineNr">3741 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3742" class="LineNr">3742 </span>  ]
<span id="L3743" class="LineNr">3743 </span>  run [
<span id="L3744" class="LineNr">3744 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3745" class="LineNr">3745 </span>  ]
<span id="L3746" class="LineNr">3746 </span>  <span class="Comment"># screen shows entire wrapped line</span>
<span id="L3747" class="LineNr">3747 </span>  screen-should-contain [
<span id="L3748" class="LineNr">3748 </span>   <span class="Constant"> .          .</span>
<span id="L3749" class="LineNr">3749 </span>   <span class="Constant"> .bcd↩      .</span>
<span id="L3750" class="LineNr">3750 </span>   <span class="Constant"> .efg↩      .</span>
<span id="L3751" class="LineNr">3751 </span>   <span class="Constant"> .h         .</span>
<span id="L3752" class="LineNr">3752 </span>  ]
<span id="L3753" class="LineNr">3753 </span>]
<span id="L3754" class="LineNr">3754 </span>
<span id="L3755" class="LineNr">3755 </span><span class="Comment"># ctrl-b/page-up - render previous page if it exists</span>
<span id="L3756" class="LineNr">3756 </span>
<span id="L3757" class="LineNr">3757 </span><span class="muScenario">scenario</span> editor-can-scroll-up [
<span id="L3758" class="LineNr">3758 </span>  <span class="Constant">local-scope</span>
<span id="L3759" class="LineNr">3759 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3760" class="LineNr">3760 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3761" class="LineNr">3761 </span><span class="Constant">b</span>
<span id="L3762" class="LineNr">3762 </span><span class="Constant">c</span>
<span id="L3763" class="LineNr">3763 </span><span class="Constant">d]</span>
<span id="L3764" class="LineNr">3764 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L3765" class="LineNr">3765 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3766" class="LineNr">3766 </span>  screen-should-contain [
<span id="L3767" class="LineNr">3767 </span>   <span class="Constant"> .          .</span>
<span id="L3768" class="LineNr">3768 </span>   <span class="Constant"> .a         .</span>
<span id="L3769" class="LineNr">3769 </span>   <span class="Constant"> .b         .</span>
<span id="L3770" class="LineNr">3770 </span>   <span class="Constant"> .c         .</span>
<span id="L3771" class="LineNr">3771 </span>  ]
<span id="L3772" class="LineNr">3772 </span>  <span class="Comment"># scroll down</span>
<span id="L3773" class="LineNr">3773 </span>  assume-console [
<span id="L3774" class="LineNr">3774 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3775" class="LineNr">3775 </span>  ]
<span id="L3776" class="LineNr">3776 </span>  run [
<span id="L3777" class="LineNr">3777 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3778" class="LineNr">3778 </span>  ]
<span id="L3779" class="LineNr">3779 </span>  <span class="Comment"># screen shows next page</span>
<span id="L3780" class="LineNr">3780 </span>  screen-should-contain [
<span id="L3781" class="LineNr">3781 </span>   <span class="Constant"> .          .</span>
<span id="L3782" class="LineNr">3782 </span>   <span class="Constant"> .c         .</span>
<span id="L3783" class="LineNr">3783 </span>   <span class="Constant"> .d         .</span>
<span id="L3784" class="LineNr">3784 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L3785" class="LineNr">3785 </span>  ]
<span id="L3786" class="LineNr">3786 </span>  <span class="Comment"># scroll back up</span>
<span id="L3787" class="LineNr">3787 </span>  assume-console [
<span id="L3788" class="LineNr">3788 </span>    press <a href='003-shortcuts.mu.html#L3833'>page-up</a>
<span id="L3789" class="LineNr">3789 </span>  ]
<span id="L3790" class="LineNr">3790 </span>  run [
<span id="L3791" class="LineNr">3791 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3792" class="LineNr">3792 </span>  ]
<span id="L3793" class="LineNr">3793 </span>  <span class="Comment"># screen shows original page again</span>
<span id="L3794" class="LineNr">3794 </span>  screen-should-contain [
<span id="L3795" class="LineNr">3795 </span>   <span class="Constant"> .          .</span>
<span id="L3796" class="LineNr">3796 </span>   <span class="Constant"> .a         .</span>
<span id="L3797" class="LineNr">3797 </span>   <span class="Constant"> .b         .</span>
<span id="L3798" class="LineNr">3798 </span>   <span class="Constant"> .c         .</span>
<span id="L3799" class="LineNr">3799 </span>  ]
<span id="L3800" class="LineNr">3800 </span>]
<span id="L3801" class="LineNr">3801 </span>
<span id="L3802" class="LineNr">3802 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L3803" class="LineNr">3803 </span>  <span class="Delimiter">{</span>
<span id="L3804" class="LineNr">3804 </span>    page-up?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">2/ctrl-b</span>
<span id="L3805" class="LineNr">3805 </span>    <span class="muControl">break-unless</span> page-up?
<span id="L3806" class="LineNr">3806 </span>    old-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L3807" class="LineNr">3807 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L3808" class="LineNr">3808 </span>    editor <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L3833'>page-up</a> editor, <a href='../081print.mu.html#L782'>screen-height</a>
<span id="L3809" class="LineNr">3809 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
<span id="L3810" class="LineNr">3810 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L3811" class="LineNr">3811 </span>    top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L3812" class="LineNr">3812 </span>    movement?:bool <span class="Special">&lt;-</span> not-equal top-of-screen, old-top
<span id="L3813" class="LineNr">3813 </span>   <span class="muControl"> return</span> movement?/go-render
<span id="L3814" class="LineNr">3814 </span>  <span class="Delimiter">}</span>
<span id="L3815" class="LineNr">3815 </span>]
<span id="L3816" class="LineNr">3816 </span>
<span id="L3817" class="LineNr">3817 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L199'>&lt;handle-special-key&gt;</a></span> [
<span id="L3818" class="LineNr">3818 </span>  <span class="Delimiter">{</span>
<span id="L3819" class="LineNr">3819 </span>    page-up?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65519/page-up</span>
<span id="L3820" class="LineNr">3820 </span>    <span class="muControl">break-unless</span> page-up?
<span id="L3821" class="LineNr">3821 </span>    old-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L3822" class="LineNr">3822 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L3823" class="LineNr">3823 </span>    editor <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L3833'>page-up</a> editor, <a href='../081print.mu.html#L782'>screen-height</a>
<span id="L3824" class="LineNr">3824 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
<span id="L3825" class="LineNr">3825 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L3826" class="LineNr">3826 </span>    top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L3827" class="LineNr">3827 </span>    movement?:bool <span class="Special">&lt;-</span> not-equal top-of-screen, old-top
<span id="L3828" class="LineNr">3828 </span>    <span class="Comment"># don't bother re-rendering if nothing changed. todo: test this</span>
<span id="L3829" class="LineNr">3829 </span>   <span class="muControl"> return</span> movement?/go-render
<span id="L3830" class="LineNr">3830 </span>  <span class="Delimiter">}</span>
<span id="L3831" class="LineNr">3831 </span>]
<span id="L3832" class="LineNr">3832 </span>
<span id="L3833" class="LineNr">3833 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L3833'>page-up</a> editor:&amp;:editor, <a href='../081print.mu.html#L782'>screen-height</a>:num<span class="muRecipe"> -&gt; </span>editor:&amp;:editor [
<span id="L3834" class="LineNr">3834 </span>  <span class="Constant">local-scope</span>
<span id="L3835" class="LineNr">3835 </span>  <span class="Constant">load-inputs</span>
<span id="L3836" class="LineNr">3836 </span>  max:num <span class="Special">&lt;-</span> subtract <a href='../081print.mu.html#L782'>screen-height</a>, <span class="Constant">1/menu-bar</span>, <span class="Constant">1/overlapping-line</span>
<span id="L3837" class="LineNr">3837 </span>  count:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
<span id="L3838" class="LineNr">3838 </span>  top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L3839" class="LineNr">3839 </span>  <span class="Delimiter">{</span>
<span id="L3840" class="LineNr">3840 </span>    done?:bool <span class="Special">&lt;-</span> greater-or-equal count, max
<span id="L3841" class="LineNr">3841 </span>    <span class="muControl">break-if</span> done?
<span id="L3842" class="LineNr">3842 </span>    <a href='../065duplex_list.mu.html#L38'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1067'>before-previous-screen-line</a> top-of-screen, editor
<span id="L3843" class="LineNr">3843 </span>    <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L38'>prev</a>
<span id="L3844" class="LineNr">3844 </span>    top-of-screen <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L38'>prev</a>
<span id="L3845" class="LineNr">3845 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top-of-screen
<span id="L3846" class="LineNr">3846 </span>    count <span class="Special">&lt;-</span> add count,<span class="Constant"> 1</span>
<span id="L3847" class="LineNr">3847 </span>   <span class="muControl"> loop</span>
<span id="L3848" class="LineNr">3848 </span>  <span class="Delimiter">}</span>
<span id="L3849" class="LineNr">3849 </span>]
<span id="L3850" class="LineNr">3850 </span>
<span id="L3851" class="LineNr">3851 </span><span class="muScenario">scenario</span> editor-can-scroll-up-multiple-pages [
<span id="L3852" class="LineNr">3852 </span>  <span class="Constant">local-scope</span>
<span id="L3853" class="LineNr">3853 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L3854" class="LineNr">3854 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3855" class="LineNr">3855 </span>  <span class="Comment"># initialize editor with 8 lines</span>
<span id="L3856" class="LineNr">3856 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3857" class="LineNr">3857 </span><span class="Constant">b</span>
<span id="L3858" class="LineNr">3858 </span><span class="Constant">c</span>
<span id="L3859" class="LineNr">3859 </span><span class="Constant">d</span>
<span id="L3860" class="LineNr">3860 </span><span class="Constant">e</span>
<span id="L3861" class="LineNr">3861 </span><span class="Constant">f</span>
<span id="L3862" class="LineNr">3862 </span><span class="Constant">g</span>
<span id="L3863" class="LineNr">3863 </span><span class="Constant">h]</span>
<span id="L3864" class="LineNr">3864 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L3865" class="LineNr">3865 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3866" class="LineNr">3866 </span>  screen-should-contain [
<span id="L3867" class="LineNr">3867 </span>   <span class="Constant"> .          .</span>
<span id="L3868" class="LineNr">3868 </span>   <span class="Constant"> .a         .</span>
<span id="L3869" class="LineNr">3869 </span>   <span class="Constant"> .b         .</span>
<span id="L3870" class="LineNr">3870 </span>   <span class="Constant"> .c         .</span>
<span id="L3871" class="LineNr">3871 </span>  ]
<span id="L3872" class="LineNr">3872 </span>  <span class="Comment"># scroll down two pages</span>
<span id="L3873" class="LineNr">3873 </span>  assume-console [
<span id="L3874" class="LineNr">3874 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3875" class="LineNr">3875 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3876" class="LineNr">3876 </span>  ]
<span id="L3877" class="LineNr">3877 </span>  run [
<span id="L3878" class="LineNr">3878 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3879" class="LineNr">3879 </span>  ]
<span id="L3880" class="LineNr">3880 </span>  <span class="Comment"># screen shows third page</span>
<span id="L3881" class="LineNr">3881 </span>  screen-should-contain [
<span id="L3882" class="LineNr">3882 </span>   <span class="Constant"> .          .</span>
<span id="L3883" class="LineNr">3883 </span>   <span class="Constant"> .e         .</span>
<span id="L3884" class="LineNr">3884 </span>   <span class="Constant"> .f         .</span>
<span id="L3885" class="LineNr">3885 </span>   <span class="Constant"> .g         .</span>
<span id="L3886" class="LineNr">3886 </span>  ]
<span id="L3887" class="LineNr">3887 </span>  <span class="Comment"># scroll up</span>
<span id="L3888" class="LineNr">3888 </span>  assume-console [
<span id="L3889" class="LineNr">3889 </span>    press <a href='003-shortcuts.mu.html#L3833'>page-up</a>
<span id="L3890" class="LineNr">3890 </span>  ]
<span id="L3891" class="LineNr">3891 </span>  run [
<span id="L3892" class="LineNr">3892 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3893" class="LineNr">3893 </span>  ]
<span id="L3894" class="LineNr">3894 </span>  <span class="Comment"># screen shows second page</span>
<span id="L3895" class="LineNr">3895 </span>  screen-should-contain [
<span id="L3896" class="LineNr">3896 </span>   <span class="Constant"> .          .</span>
<span id="L3897" class="LineNr">3897 </span>   <span class="Constant"> .c         .</span>
<span id="L3898" class="LineNr">3898 </span>   <span class="Constant"> .d         .</span>
<span id="L3899" class="LineNr">3899 </span>   <span class="Constant"> .e         .</span>
<span id="L3900" class="LineNr">3900 </span>  ]
<span id="L3901" class="LineNr">3901 </span>  <span class="Comment"># scroll up again</span>
<span id="L3902" class="LineNr">3902 </span>  assume-console [
<span id="L3903" class="LineNr">3903 </span>    press <a href='003-shortcuts.mu.html#L3833'>page-up</a>
<span id="L3904" class="LineNr">3904 </span>  ]
<span id="L3905" class="LineNr">3905 </span>  run [
<span id="L3906" class="LineNr">3906 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3907" class="LineNr">3907 </span>  ]
<span id="L3908" class="LineNr">3908 </span>  <span class="Comment"># screen shows original page again</span>
<span id="L3909" class="LineNr">3909 </span>  screen-should-contain [
<span id="L3910" class="LineNr">3910 </span>   <span class="Constant"> .          .</span>
<span id="L3911" class="LineNr">3911 </span>   <span class="Constant"> .a         .</span>
<span id="L3912" class="LineNr">3912 </span>   <span class="Constant"> .b         .</span>
<span id="L3913" class="LineNr">3913 </span>   <span class="Constant"> .c         .</span>
<span id="L3914" class="LineNr">3914 </span>  ]
<span id="L3915" class="LineNr">3915 </span>]
<span id="L3916" class="LineNr">3916 </span>
<span id="L3917" class="LineNr">3917 </span><span class="muScenario">scenario</span> editor-can-scroll-up-wrapped-lines [
<span id="L3918" class="LineNr">3918 </span>  <span class="Constant">local-scope</span>
<span id="L3919" class="LineNr">3919 </span>  <span class="Comment"># screen has 1 line for menu + 5 lines for text</span>
<span id="L3920" class="LineNr">3920 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">6/height</span>
<span id="L3921" class="LineNr">3921 </span>  <span class="Comment"># editor contains a long line in the first page</span>
<span id="L3922" class="LineNr">3922 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3923" class="LineNr">3923 </span><span class="Constant">b</span>
<span id="L3924" class="LineNr">3924 </span><span class="Constant">cdefgh</span>
<span id="L3925" class="LineNr">3925 </span><span class="Constant">i</span>
<span id="L3926" class="LineNr">3926 </span><span class="Constant">j</span>
<span id="L3927" class="LineNr">3927 </span><span class="Constant">k</span>
<span id="L3928" class="LineNr">3928 </span><span class="Constant">l</span>
<span id="L3929" class="LineNr">3929 </span><span class="Constant">m</span>
<span id="L3930" class="LineNr">3930 </span><span class="Constant">n</span>
<span id="L3931" class="LineNr">3931 </span><span class="Constant">o]</span>
<span id="L3932" class="LineNr">3932 </span>  <span class="Comment"># editor screen triggers wrap of last line</span>
<span id="L3933" class="LineNr">3933 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">4/right</span>
<span id="L3934" class="LineNr">3934 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3935" class="LineNr">3935 </span>  <span class="Comment"># some part of last line is not displayed</span>
<span id="L3936" class="LineNr">3936 </span>  screen-should-contain [
<span id="L3937" class="LineNr">3937 </span>   <span class="Constant"> .          .</span>
<span id="L3938" class="LineNr">3938 </span>   <span class="Constant"> .a         .</span>
<span id="L3939" class="LineNr">3939 </span>   <span class="Constant"> .b         .</span>
<span id="L3940" class="LineNr">3940 </span>   <span class="Constant"> .cde↩      .</span>
<span id="L3941" class="LineNr">3941 </span>   <span class="Constant"> .fgh       .</span>
<span id="L3942" class="LineNr">3942 </span>   <span class="Constant"> .i         .</span>
<span id="L3943" class="LineNr">3943 </span>  ]
<span id="L3944" class="LineNr">3944 </span>  <span class="Comment"># scroll down a page and a line</span>
<span id="L3945" class="LineNr">3945 </span>  assume-console [
<span id="L3946" class="LineNr">3946 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3947" class="LineNr">3947 </span>    left-click<span class="Constant"> 5</span>,<span class="Constant"> 0</span>
<span id="L3948" class="LineNr">3948 </span>    press down-arrow
<span id="L3949" class="LineNr">3949 </span>  ]
<span id="L3950" class="LineNr">3950 </span>  run [
<span id="L3951" class="LineNr">3951 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3952" class="LineNr">3952 </span>  ]
<span id="L3953" class="LineNr">3953 </span>  <span class="Comment"># screen shows entire wrapped line</span>
<span id="L3954" class="LineNr">3954 </span>  screen-should-contain [
<span id="L3955" class="LineNr">3955 </span>   <span class="Constant"> .          .</span>
<span id="L3956" class="LineNr">3956 </span>   <span class="Constant"> .j         .</span>
<span id="L3957" class="LineNr">3957 </span>   <span class="Constant"> .k         .</span>
<span id="L3958" class="LineNr">3958 </span>   <span class="Constant"> .l         .</span>
<span id="L3959" class="LineNr">3959 </span>   <span class="Constant"> .m         .</span>
<span id="L3960" class="LineNr">3960 </span>   <span class="Constant"> .n         .</span>
<span id="L3961" class="LineNr">3961 </span>  ]
<span id="L3962" class="LineNr">3962 </span>  <span class="Comment"># now scroll up one page</span>
<span id="L3963" class="LineNr">3963 </span>  assume-console [
<span id="L3964" class="LineNr">3964 </span>    press <a href='003-shortcuts.mu.html#L3833'>page-up</a>
<span id="L3965" class="LineNr">3965 </span>  ]
<span id="L3966" class="LineNr">3966 </span>  run [
<span id="L3967" class="LineNr">3967 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3968" class="LineNr">3968 </span>  ]
<span id="L3969" class="LineNr">3969 </span>  <span class="Comment"># screen resets</span>
<span id="L3970" class="LineNr">3970 </span>  screen-should-contain [
<span id="L3971" class="LineNr">3971 </span>   <span class="Constant"> .          .</span>
<span id="L3972" class="LineNr">3972 </span>   <span class="Constant"> .b         .</span>
<span id="L3973" class="LineNr">3973 </span>   <span class="Constant"> .cde↩      .</span>
<span id="L3974" class="LineNr">3974 </span>   <span class="Constant"> .fgh       .</span>
<span id="L3975" class="LineNr">3975 </span>   <span class="Constant"> .i         .</span>
<span id="L3976" class="LineNr">3976 </span>   <span class="Constant"> .j         .</span>
<span id="L3977" class="LineNr">3977 </span>  ]
<span id="L3978" class="LineNr">3978 </span>]
<span id="L3979" class="LineNr">3979 </span>
<span id="L3980" class="LineNr">3980 </span><span class="muScenario">scenario</span> editor-can-scroll-up-wrapped-lines-2 [
<span id="L3981" class="LineNr">3981 </span>  <span class="Constant">local-scope</span>
<span id="L3982" class="LineNr">3982 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines for text</span>
<span id="L3983" class="LineNr">3983 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3984" class="LineNr">3984 </span>  <span class="Comment"># editor contains a very long line that occupies last two lines of screen</span>
<span id="L3985" class="LineNr">3985 </span>  <span class="Comment"># and still has something left over</span>
<span id="L3986" class="LineNr">3986 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3987" class="LineNr">3987 </span><span class="Constant">bcdefgh]</span>
<span id="L3988" class="LineNr">3988 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">4/right</span>
<span id="L3989" class="LineNr">3989 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3990" class="LineNr">3990 </span>  <span class="Comment"># some part of last line is not displayed</span>
<span id="L3991" class="LineNr">3991 </span>  screen-should-contain [
<span id="L3992" class="LineNr">3992 </span>   <span class="Constant"> .          .</span>
<span id="L3993" class="LineNr">3993 </span>   <span class="Constant"> .a         .</span>
<span id="L3994" class="LineNr">3994 </span>   <span class="Constant"> .bcd↩      .</span>
<span id="L3995" class="LineNr">3995 </span>   <span class="Constant"> .efg↩      .</span>
<span id="L3996" class="LineNr">3996 </span>  ]
<span id="L3997" class="LineNr">3997 </span>  <span class="Comment"># scroll down</span>
<span id="L3998" class="LineNr">3998 </span>  assume-console [
<span id="L3999" class="LineNr">3999 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L4000" class="LineNr">4000 </span>  ]
<span id="L4001" class="LineNr">4001 </span>  run [
<span id="L4002" class="LineNr">4002 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4003" class="LineNr">4003 </span>  ]
<span id="L4004" class="LineNr">4004 </span>  <span class="Comment"># screen shows entire wrapped line</span>
<span id="L4005" class="LineNr">4005 </span>  screen-should-contain [
<span id="L4006" class="LineNr">4006 </span>   <span class="Constant"> .          .</span>
<span id="L4007" class="LineNr">4007 </span>   <span class="Constant"> .bcd↩      .</span>
<span id="L4008" class="LineNr">4008 </span>   <span class="Constant"> .efg↩      .</span>
<span id="L4009" class="LineNr">4009 </span>   <span class="Constant"> .h         .</span>
<span id="L4010" class="LineNr">4010 </span>  ]
<span id="L4011" class="LineNr">4011 </span>  <span class="Comment"># scroll back up</span>
<span id="L4012" class="LineNr">4012 </span>  assume-console [
<span id="L4013" class="LineNr">4013 </span>    press <a href='003-shortcuts.mu.html#L3833'>page-up</a>
<span id="L4014" class="LineNr">4014 </span>  ]
<span id="L4015" class="LineNr">4015 </span>  run [
<span id="L4016" class="LineNr">4016 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4017" class="LineNr">4017 </span>  ]
<span id="L4018" class="LineNr">4018 </span>  <span class="Comment"># screen resets</span>
<span id="L4019" class="LineNr">4019 </span>  screen-should-contain [
<span id="L4020" class="LineNr">4020 </span>   <span class="Constant"> .          .</span>
<span id="L4021" class="LineNr">4021 </span>   <span class="Constant"> .a         .</span>
<span id="L4022" class="LineNr">4022 </span>   <span class="Constant"> .bcd↩      .</span>
<span id="L4023" class="LineNr">4023 </span>   <span class="Constant"> .efg↩      .</span>
<span id="L4024" class="LineNr">4024 </span>  ]
<span id="L4025" class="LineNr">4025 </span>]
<span id="L4026" class="LineNr">4026 </span>
<span id="L4027" class="LineNr">4027 </span><span class="muScenario">scenario</span> editor-can-scroll-up-past-nonempty-lines [
<span id="L4028" class="LineNr">4028 </span>  <span class="Constant">local-scope</span>
<span id="L4029" class="LineNr">4029 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L4030" class="LineNr">4030 </span>  <span class="Comment"># text with empty line in second screen</span>
<span id="L4031" class="LineNr">4031 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[axx</span>
<span id="L4032" class="LineNr">4032 </span><span class="Constant">bxx</span>
<span id="L4033" class="LineNr">4033 </span><span class="Constant">cxx</span>
<span id="L4034" class="LineNr">4034 </span><span class="Constant">dxx</span>
<span id="L4035" class="LineNr">4035 </span><span class="Constant">exx</span>
<span id="L4036" class="LineNr">4036 </span><span class="Constant">fxx</span>
<span id="L4037" class="LineNr">4037 </span><span class="Constant">gxx</span>
<span id="L4038" class="LineNr">4038 </span><span class="Constant">hxx</span>
<span id="L4039" class="LineNr">4039 </span><span class="Constant">]</span>
<span id="L4040" class="LineNr">4040 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">4/right</span>
<span id="L4041" class="LineNr">4041 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L4042" class="LineNr">4042 </span>  screen-should-contain [
<span id="L4043" class="LineNr">4043 </span>   <span class="Constant"> .          .</span>
<span id="L4044" class="LineNr">4044 </span>   <span class="Constant"> .axx       .</span>
<span id="L4045" class="LineNr">4045 </span>   <span class="Constant"> .bxx       .</span>
<span id="L4046" class="LineNr">4046 </span>   <span class="Constant"> .cxx       .</span>
<span id="L4047" class="LineNr">4047 </span>  ]
<span id="L4048" class="LineNr">4048 </span>  assume-console [
<span id="L4049" class="LineNr">4049 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L4050" class="LineNr">4050 </span>  ]
<span id="L4051" class="LineNr">4051 </span>  run [
<span id="L4052" class="LineNr">4052 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4053" class="LineNr">4053 </span>  ]
<span id="L4054" class="LineNr">4054 </span>  screen-should-contain [
<span id="L4055" class="LineNr">4055 </span>   <span class="Constant"> .          .</span>
<span id="L4056" class="LineNr">4056 </span>   <span class="Constant"> .cxx       .</span>
<span id="L4057" class="LineNr">4057 </span>   <span class="Constant"> .dxx       .</span>
<span id="L4058" class="LineNr">4058 </span>   <span class="Constant"> .exx       .</span>
<span id="L4059" class="LineNr">4059 </span>  ]
<span id="L4060" class="LineNr">4060 </span>  assume-console [
<span id="L4061" class="LineNr">4061 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L4062" class="LineNr">4062 </span>  ]
<span id="L4063" class="LineNr">4063 </span>  run [
<span id="L4064" class="LineNr">4064 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4065" class="LineNr">4065 </span>  ]
<span id="L4066" class="LineNr">4066 </span>  screen-should-contain [
<span id="L4067" class="LineNr">4067 </span>   <span class="Constant"> .          .</span>
<span id="L4068" class="LineNr">4068 </span>   <span class="Constant"> .exx       .</span>
<span id="L4069" class="LineNr">4069 </span>   <span class="Constant"> .fxx       .</span>
<span id="L4070" class="LineNr">4070 </span>   <span class="Constant"> .gxx       .</span>
<span id="L4071" class="LineNr">4071 </span>  ]
<span id="L4072" class="LineNr">4072 </span>  <span class="Comment"># scroll back up past empty line</span>
<span id="L4073" class="LineNr">4073 </span>  assume-console [
<span id="L4074" class="LineNr">4074 </span>    press <a href='003-shortcuts.mu.html#L3833'>page-up</a>
<span id="L4075" class="LineNr">4075 </span>  ]
<span id="L4076" class="LineNr">4076 </span>  run [
<span id="L4077" class="LineNr">4077 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4078" class="LineNr">4078 </span>  ]
<span id="L4079" class="LineNr">4079 </span>  screen-should-contain [
<span id="L4080" class="LineNr">4080 </span>   <span class="Constant"> .          .</span>
<span id="L4081" class="LineNr">4081 </span>   <span class="Constant"> .cxx       .</span>
<span id="L4082" class="LineNr">4082 </span>   <span class="Constant"> .dxx       .</span>
<span id="L4083" class="LineNr">4083 </span>   <span class="Constant"> .exx       .</span>
<span id="L4084" class="LineNr">4084 </span>  ]
<span id="L4085" class="LineNr">4085 </span>]
<span id="L4086" class="LineNr">4086 </span>
<span id="L4087" class="LineNr">4087 </span><span class="muScenario">scenario</span> editor-can-scroll-up-past-empty-lines [
<span id="L4088" class="LineNr">4088 </span>  <span class="Constant">local-scope</span>
<span id="L4089" class="LineNr">4089 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L4090" class="LineNr">4090 </span>  <span class="Comment"># text with empty line in second screen</span>
<span id="L4091" class="LineNr">4091 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[axy</span>
<span id="L4092" class="LineNr">4092 </span><span class="Constant">bxy</span>
<span id="L4093" class="LineNr">4093 </span><span class="Constant">cxy</span>
<span id="L4094" class="LineNr">4094 </span>
<span id="L4095" class="LineNr">4095 </span>dxy
<span id="L4096" class="LineNr">4096 </span>exy
<span id="L4097" class="LineNr">4097 </span>fxy
<span id="L4098" class="LineNr">4098 </span>gxy
<span id="L4099" class="LineNr">4099 </span>]
<span id="L4100" class="LineNr">4100 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">4/right</span>
<span id="L4101" class="LineNr">4101 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L4102" class="LineNr">4102 </span>  screen-should-contain [
<span id="L4103" class="LineNr">4103 </span>   <span class="Constant"> .          .</span>
<span id="L4104" class="LineNr">4104 </span>   <span class="Constant"> .axy       .</span>
<span id="L4105" class="LineNr">4105 </span>   <span class="Constant"> .bxy       .</span>
<span id="L4106" class="LineNr">4106 </span>   <span class="Constant"> .cxy       .</span>
<span id="L4107" class="LineNr">4107 </span>  ]
<span id="L4108" class="LineNr">4108 </span>  assume-console [
<span id="L4109" class="LineNr">4109 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L4110" class="LineNr">4110 </span>  ]
<span id="L4111" class="LineNr">4111 </span>  run [
<span id="L4112" class="LineNr">4112 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4113" class="LineNr">4113 </span>  ]
<span id="L4114" class="LineNr">4114 </span>  screen-should-contain [
<span id="L4115" class="LineNr">4115 </span>   <span class="Constant"> .          .</span>
<span id="L4116" class="LineNr">4116 </span>   <span class="Constant"> .cxy       .</span>
<span id="L4117" class="LineNr">4117 </span>   <span class="Constant"> .          .</span>
<span id="L4118" class="LineNr">4118 </span>   <span class="Constant"> .dxy       .</span>
<span id="L4119" class="LineNr">4119 </span>  ]
<span id="L4120" class="LineNr">4120 </span>  assume-console [
<span id="L4121" class="LineNr">4121 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L4122" class="LineNr">4122 </span>  ]
<span id="L4123" class="LineNr">4123 </span>  run [
<span id="L4124" class="LineNr">4124 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4125" class="LineNr">4125 </span>  ]
<span id="L4126" class="LineNr">4126 </span>  screen-should-contain [
<span id="L4127" class="LineNr">4127 </span>   <span class="Constant"> .          .</span>
<span id="L4128" class="LineNr">4128 </span>   <span class="Constant"> .dxy       .</span>
<span id="L4129" class="LineNr">4129 </span>   <span class="Constant"> .exy       .</span>
<span id="L4130" class="LineNr">4130 </span>   <span class="Constant"> .fxy       .</span>
<span id="L4131" class="LineNr">4131 </span>  ]
<span id="L4132" class="LineNr">4132 </span>  <span class="Comment"># scroll back up past empty line</span>
<span id="L4133" class="LineNr">4133 </span>  assume-console [
<span id="L4134" class="LineNr">4134 </span>    press <a href='003-shortcuts.mu.html#L3833'>page-up</a>
<span id="L4135" class="LineNr">4135 </span>  ]
<span id="L4136" class="LineNr">4136 </span>  run [
<span id="L4137" class="LineNr">4137 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4138" class="LineNr">4138 </span>  ]
<span id="L4139" class="LineNr">4139 </span>  screen-should-contain [
<span id="L4140" class="LineNr">4140 </span>   <span class="Constant"> .          .</span>
<span id="L4141" class="LineNr">4141 </span>   <span class="Constant"> .cxy       .</span>
<span id="L4142" class="LineNr">4142 </span>   <span class="Constant"> .          .</span>
<span id="L4143" class="LineNr">4143 </span>   <span class="Constant"> .dxy       .</span>
<span id="L4144" class="LineNr">4144 </span>  ]
<span id="L4145" class="LineNr">4145 </span>]
<span id="L4146" class="LineNr">4146 </span>
<span id="L4147" class="LineNr">4147 </span><span class="Comment"># ctrl-s - scroll up by one line</span>
<span id="L4148" class="LineNr">4148 </span><span class="Comment"># todo: scenarios</span>
<span id="L4149" class="LineNr">4149 </span>
<span id="L4150" class="LineNr">4150 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L4151" class="LineNr">4151 </span>  <span class="Delimiter">{</span>
<span id="L4152" class="LineNr">4152 </span>    scroll-up?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">19/ctrl-s</span>
<span id="L4153" class="LineNr">4153 </span>    <span class="muControl">break-unless</span> scroll-up?
<span id="L4154" class="LineNr">4154 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L4155" class="LineNr">4155 </span>    go-render?:bool, editor <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L4162'>line-up</a> editor, <a href='../081print.mu.html#L782'>screen-height</a>
<span id="L4156" class="LineNr">4156 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">5/line-up</span>
<span id="L4157" class="LineNr">4157 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L4158" class="LineNr">4158 </span>   <span class="muControl"> return</span> go-render?
<span id="L4159" class="LineNr">4159 </span>  <span class="Delimiter">}</span>
<span id="L4160" class="LineNr">4160 </span>]
<span id="L4161" class="LineNr">4161 </span>
<span id="L4162" class="LineNr">4162 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L4162'>line-up</a> editor:&amp;:editor, <a href='../081print.mu.html#L782'>screen-height</a>:num<span class="muRecipe"> -&gt; </span>go-render?:bool, editor:&amp;:editor [
<span id="L4163" class="LineNr">4163 </span>  <span class="Constant">local-scope</span>
<span id="L4164" class="LineNr">4164 </span>  <span class="Constant">load-inputs</span>
<span id="L4165" class="LineNr">4165 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L4166" class="LineNr">4166 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L4167" class="LineNr">4167 </span>  max:num <span class="Special">&lt;-</span> subtract right, left
<span id="L4168" class="LineNr">4168 </span>  old-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L4169" class="LineNr">4169 </span>  new-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2862'>before-start-of-next-line</a> old-top, max
<span id="L4170" class="LineNr">4170 </span>  movement?:bool <span class="Special">&lt;-</span> not-equal old-top, new-top
<span id="L4171" class="LineNr">4171 </span>  <span class="Delimiter">{</span>
<span id="L4172" class="LineNr">4172 </span>    <span class="muControl">break-unless</span> movement?
<span id="L4173" class="LineNr">4173 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, new-top
<span id="L4174" class="LineNr">4174 </span>  <span class="Delimiter">}</span>
<span id="L4175" class="LineNr">4175 </span> <span class="muControl"> return</span> movement?
<span id="L4176" class="LineNr">4176 </span>]
<span id="L4177" class="LineNr">4177 </span>
<span id="L4178" class="LineNr">4178 </span><span class="Comment"># ctrl-x - scroll down by one line</span>
<span id="L4179" class="LineNr">4179 </span><span class="Comment"># todo: scenarios</span>
<span id="L4180" class="LineNr">4180 </span>
<span id="L4181" class="LineNr">4181 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L4182" class="LineNr">4182 </span>  <span class="Delimiter">{</span>
<span id="L4183" class="LineNr">4183 </span>    scroll-down?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">24/ctrl-x</span>
<span id="L4184" class="LineNr">4184 </span>    <span class="muControl">break-unless</span> scroll-down?
<span id="L4185" class="LineNr">4185 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L4186" class="LineNr">4186 </span>    go-render?:bool, editor <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L4193'>line-down</a> editor, <a href='../081print.mu.html#L782'>screen-height</a>
<span id="L4187" class="LineNr">4187 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">6/line-down</span>
<span id="L4188" class="LineNr">4188 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L4189" class="LineNr">4189 </span>   <span class="muControl"> return</span> go-render?
<span id="L4190" class="LineNr">4190 </span>  <span class="Delimiter">}</span>
<span id="L4191" class="LineNr">4191 </span>]
<span id="L4192" class="LineNr">4192 </span>
<span id="L4193" class="LineNr">4193 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L4193'>line-down</a> editor:&amp;:editor, <a href='../081print.mu.html#L782'>screen-height</a>:num<span class="muRecipe"> -&gt; </span>go-render?:bool, editor:&amp;:editor [
<span id="L4194" class="LineNr">4194 </span>  <span class="Constant">local-scope</span>
<span id="L4195" class="LineNr">4195 </span>  <span class="Constant">load-inputs</span>
<span id="L4196" class="LineNr">4196 </span>  old-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L4197" class="LineNr">4197 </span>  new-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1067'>before-previous-screen-line</a> old-top, editor
<span id="L4198" class="LineNr">4198 </span>  movement?:bool <span class="Special">&lt;-</span> not-equal old-top, new-top
<span id="L4199" class="LineNr">4199 </span>  <span class="Delimiter">{</span>
<span id="L4200" class="LineNr">4200 </span>    <span class="muControl">break-unless</span> movement?
<span id="L4201" class="LineNr">4201 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, new-top
<span id="L4202" class="LineNr">4202 </span>  <span class="Delimiter">}</span>
<span id="L4203" class="LineNr">4203 </span> <span class="muControl"> return</span> movement?
<span id="L4204" class="LineNr">4204 </span>]
<span id="L4205" class="LineNr">4205 </span>
<span id="L4206" class="LineNr">4206 </span><span class="Comment"># ctrl-t - move current line to top of screen</span>
<span id="L4207" class="LineNr">4207 </span><span class="Comment"># todo: scenarios</span>
<span id="L4208" class="LineNr">4208 </span>
<span id="L4209" class="LineNr">4209 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L4210" class="LineNr">4210 </span>  <span class="Delimiter">{</span>
<span id="L4211" class="LineNr">4211 </span>    scroll-down?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">20/ctrl-t</span>
<span id="L4212" class="LineNr">4212 </span>    <span class="muControl">break-unless</span> scroll-down?
<span id="L4213" class="LineNr">4213 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L4214" class="LineNr">4214 </span>    old-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L4215" class="LineNr">4215 </span>    cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L4216" class="LineNr">4216 </span>    cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> cursor
<span id="L4217" class="LineNr">4217 </span>    new-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1067'>before-previous-screen-line</a> cursor, editor
<span id="L4218" class="LineNr">4218 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, new-top
<span id="L4219" class="LineNr">4219 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>,<span class="Constant"> 1</span>
<span id="L4220" class="LineNr">4220 </span>    go-render?:bool <span class="Special">&lt;-</span> not-equal new-top, old-top
<span id="L4221" class="LineNr">4221 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
<span id="L4222" class="LineNr">4222 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L4223" class="LineNr">4223 </span>   <span class="muControl"> return</span> go-render?
<span id="L4224" class="LineNr">4224 </span>  <span class="Delimiter">}</span>
<span id="L4225" class="LineNr">4225 </span>]
<span id="L4226" class="LineNr">4226 </span>
<span id="L4227" class="LineNr">4227 </span><span class="Comment"># ctrl-/ - comment/uncomment current line</span>
<span id="L4228" class="LineNr">4228 </span>
<span id="L4229" class="LineNr">4229 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L4230" class="LineNr">4230 </span>  <span class="Delimiter">{</span>
<span id="L4231" class="LineNr">4231 </span>    comment-toggle?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">31/ctrl-slash</span>
<span id="L4232" class="LineNr">4232 </span>    <span class="muControl">break-unless</span> comment-toggle?
<span id="L4233" class="LineNr">4233 </span>    cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L4234" class="LineNr">4234 </span>    data:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
<span id="L4235" class="LineNr">4235 </span><span class="Constant">    &lt;begin-insert-character&gt;</span>
<span id="L4236" class="LineNr">4236 </span>    before-line-start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L4293'>before-start-of-screen-line</a> editor
<span id="L4237" class="LineNr">4237 </span>    line-start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-line-start
<span id="L4238" class="LineNr">4238 </span>    commented-out?:bool <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L642'>match</a> line-start, <span class="Constant">[#? ]</span>  <span class="Comment"># comment prefix</span>
<span id="L4239" class="LineNr">4239 </span>    <span class="Delimiter">{</span>
<span id="L4240" class="LineNr">4240 </span>      <span class="muControl">break-unless</span> commented-out?
<span id="L4241" class="LineNr">4241 </span>      <span class="Comment"># uncomment</span>
<span id="L4242" class="LineNr">4242 </span>      data <span class="Special">&lt;-</span> remove line-start, <span class="Constant">3/length-comment-prefix</span>, data
<span id="L4243" class="LineNr">4243 </span>      cursor-column <span class="Special">&lt;-</span> subtract cursor-column, <span class="Constant">3/length-comment-prefix</span>
<span id="L4244" class="LineNr">4244 </span>      *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L4245" class="LineNr">4245 </span>      go-render? <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L4263'>render-line-from-start</a> <a href='../081print.mu.html#L16'>screen</a>, editor, <span class="Constant">3/size-of-comment-leader</span>
<span id="L4246" class="LineNr">4246 </span>    <span class="Delimiter">}</span>
<span id="L4247" class="LineNr">4247 </span>    <span class="Delimiter">{</span>
<span id="L4248" class="LineNr">4248 </span>      <span class="muControl">break-if</span> commented-out?
<span id="L4249" class="LineNr">4249 </span>      <span class="Comment"># comment</span>
<span id="L4250" class="LineNr">4250 </span>      insert before-line-start, <span class="Constant">[#? ]</span>
<span id="L4251" class="LineNr">4251 </span>      cursor-column <span class="Special">&lt;-</span> add cursor-column, <span class="Constant">3/length-comment-prefix</span>
<span id="L4252" class="LineNr">4252 </span>      *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L4253" class="LineNr">4253 </span>      go-render? <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L4263'>render-line-from-start</a> <a href='../081print.mu.html#L16'>screen</a>, editor,<span class="Constant"> 0</span>
<span id="L4254" class="LineNr">4254 </span>    <span class="Delimiter">}</span>
<span id="L4255" class="LineNr">4255 </span><span class="Constant">    &lt;end-insert-character&gt;</span>
<span id="L4256" class="LineNr">4256 </span>   <span class="muControl"> return</span>
<span id="L4257" class="LineNr">4257 </span>  <span class="Delimiter">}</span>
<span id="L4258" class="LineNr">4258 </span>]
<span id="L4259" class="LineNr">4259 </span>
<span id="L4260" class="LineNr">4260 </span><span class="Comment"># Render just from the start of the current line, and only if it wasn't</span>
<span id="L4261" class="LineNr">4261 </span><span class="Comment"># wrapping before (include margin) and isn't wrapping now. Otherwise just tell</span>
<span id="L4262" class="LineNr">4262 </span><span class="Comment"># the caller to go-render? the entire screen.</span>
<span id="L4263" class="LineNr">4263 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L4263'>render-line-from-start</a> <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a>, editor:&amp;:editor, right-margin:num<span class="muRecipe"> -&gt; </span>go-render?:bool, <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a> [
<span id="L4264" class="LineNr">4264 </span>  <span class="Constant">local-scope</span>
<span id="L4265" class="LineNr">4265 </span>  <span class="Constant">load-inputs</span>
<span id="L4266" class="LineNr">4266 </span>  before-line-start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L4293'>before-start-of-screen-line</a> editor
<span id="L4267" class="LineNr">4267 </span>  line-start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-line-start
<span id="L4268" class="LineNr">4268 </span>  color:num <span class="Special">&lt;-</span> copy <span class="Constant">7/white</span>
<span id="L4269" class="LineNr">4269 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L4270" class="LineNr">4270 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L4271" class="LineNr">4271 </span>  <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> move-cursor <a href='../081print.mu.html#L16'>screen</a>, cursor-row, left
<span id="L4272" class="LineNr">4272 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L4273" class="LineNr">4273 </span>  end:num <span class="Special">&lt;-</span> subtract right, right-margin
<span id="L4274" class="LineNr">4274 </span>  i:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
<span id="L4275" class="LineNr">4275 </span>  curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy line-start
<span id="L4276" class="LineNr">4276 </span>  <span class="Delimiter">{</span>
<span id="L4277" class="LineNr">4277 </span>    render-all?:bool <span class="Special">&lt;-</span> greater-or-equal i, end
<span id="L4278" class="LineNr">4278 </span>    <span class="muControl">return-if</span> render-all?,<span class="Constant"> true/go-render</span>
<span id="L4279" class="LineNr">4279 </span>    <span class="muControl">break-unless</span> curr
<span id="L4280" class="LineNr">4280 </span>    c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
<span id="L4281" class="LineNr">4281 </span>    newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
<span id="L4282" class="LineNr">4282 </span>    <span class="muControl">break-if</span> newline?
<span id="L4283" class="LineNr">4283 </span>    color <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L400'>get-color</a> color, c
<span id="L4284" class="LineNr">4284 </span>    print <a href='../081print.mu.html#L16'>screen</a>, c, color
<span id="L4285" class="LineNr">4285 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> curr
<span id="L4286" class="LineNr">4286 </span>    i <span class="Special">&lt;-</span> add i,<span class="Constant"> 1</span>
<span id="L4287" class="LineNr">4287 </span>   <span class="muControl"> loop</span>
<span id="L4288" class="LineNr">4288 </span>  <span class="Delimiter">}</span>
<span id="L4289" class="LineNr">4289 </span>  <a href='../081print.mu.html#L553'>clear-line-until</a> <a href='../081print.mu.html#L16'>screen</a>, right
<span id="L4290" class="LineNr">4290 </span> <span class="muControl"> return</span><span class="Constant"> false/dont-render</span>
<span id="L4291" class="LineNr">4291 </span>]
<span id="L4292" class="LineNr">4292 </span>
<span id="L4293" class="LineNr">4293 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L4293'>before-start-of-screen-line</a> editor:&amp;:editor<span class="muRecipe"> -&gt; </span>result:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char [
<span id="L4294" class="LineNr">4294 </span>  <span class="Constant">local-scope</span>
<span id="L4295" class="LineNr">4295 </span>  <span class="Constant">load-inputs</span>
<span id="L4296" class="LineNr">4296 </span>  cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L4297" class="LineNr">4297 </span>  <span class="Delimiter">{</span>
<span id="L4298" class="LineNr">4298 </span>    <a href='../065duplex_list.mu.html#L31'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> cursor
<span id="L4299" class="LineNr">4299 </span>    <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L31'>next</a>
<span id="L4300" class="LineNr">4300 </span>    cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L31'>next</a>
<span id="L4301" class="LineNr">4301 </span>  <span class="Delimiter">}</span>
<span id="L4302" class="LineNr">4302 </span>  result <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1067'>before-previous-screen-line</a> cursor, editor
<span id="L4303" class="LineNr">4303 </span>]
<span id="L4304" class="LineNr">4304 </span>
<span id="L4305" class="LineNr">4305 </span><span class="muScenario">scenario</span> editor-comments-empty-line [
<span id="L4306" class="LineNr">4306 </span>  <span class="Constant">local-scope</span>
<span id="L4307" class="LineNr">4307 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L4308" class="LineNr">4308 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L4309" class="LineNr">4309 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L4310" class="LineNr">4310 </span>  $clear-trace
<span id="L4311" class="LineNr">4311 </span>  assume-console [
<span id="L4312" class="LineNr">4312 </span>    press ctrl-slash
<span id="L4313" class="LineNr">4313 </span>  ]
<span id="L4314" class="LineNr">4314 </span>  run [
<span id="L4315" class="LineNr">4315 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4316" class="LineNr">4316 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L4317" class="LineNr">4317 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L4318" class="LineNr">4318 </span>  ]
<span id="L4319" class="LineNr">4319 </span>  screen-should-contain [
<span id="L4320" class="LineNr">4320 </span>   <span class="Constant"> .          .</span>
<span id="L4321" class="LineNr">4321 </span>   <span class="Constant"> .#?        .</span>
<span id="L4322" class="LineNr">4322 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L4323" class="LineNr">4323 </span>   <span class="Constant"> .          .</span>
<span id="L4324" class="LineNr">4324 </span>  ]
<span id="L4325" class="LineNr">4325 </span>  memory-should-contain [
<span id="L4326" class="LineNr">4326 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L4327" class="LineNr">4327 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L4328" class="LineNr">4328 </span>  ]
<span id="L4329" class="LineNr">4329 </span>  check-trace-count-for-label<span class="Constant"> 5</span>, <span class="Constant">[print-character]</span>
<span id="L4330" class="LineNr">4330 </span>]
<span id="L4331" class="LineNr">4331 </span>
<span id="L4332" class="LineNr">4332 </span><span class="muScenario">scenario</span> editor-comments-at-start-of-contents [
<span id="L4333" class="LineNr">4333 </span>  <span class="Constant">local-scope</span>
<span id="L4334" class="LineNr">4334 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L4335" class="LineNr">4335 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[ab]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L4336" class="LineNr">4336 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L4337" class="LineNr">4337 </span>  $clear-trace
<span id="L4338" class="LineNr">4338 </span>  assume-console [
<span id="L4339" class="LineNr">4339 </span>    press ctrl-slash
<span id="L4340" class="LineNr">4340 </span>  ]
<span id="L4341" class="LineNr">4341 </span>  run [
<span id="L4342" class="LineNr">4342 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4343" class="LineNr">4343 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L4344" class="LineNr">4344 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L4345" class="LineNr">4345 </span>  ]
<span id="L4346" class="LineNr">4346 </span>  screen-should-contain [
<span id="L4347" class="LineNr">4347 </span>   <span class="Constant"> .          .</span>
<span id="L4348" class="LineNr">4348 </span>   <span class="Constant"> .#? ab     .</span>
<span id="L4349" class="LineNr">4349 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L4350" class="LineNr">4350 </span>   <span class="Constant"> .          .</span>
<span id="L4351" class="LineNr">4351 </span>  ]
<span id="L4352" class="LineNr">4352 </span>  memory-should-contain [
<span id="L4353" class="LineNr">4353 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L4354" class="LineNr">4354 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L4355" class="LineNr">4355 </span>  ]
<span id="L4356" class="LineNr">4356 </span>  check-trace-count-for-label<span class="Constant"> 10</span>, <span class="Constant">[print-character]</span>
<span id="L4357" class="LineNr">4357 </span>]
<span id="L4358" class="LineNr">4358 </span>
<span id="L4359" class="LineNr">4359 </span><span class="muScenario">scenario</span> editor-comments-at-end-of-contents [
<span id="L4360" class="LineNr">4360 </span>  <span class="Constant">local-scope</span>
<span id="L4361" class="LineNr">4361 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L4362" class="LineNr">4362 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[ab]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L4363" class="LineNr">4363 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L4364" class="LineNr">4364 </span>  $clear-trace
<span id="L4365" class="LineNr">4365 </span>  assume-console [
<span id="L4366" class="LineNr">4366 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 7</span>
<span id="L4367" class="LineNr">4367 </span>    press ctrl-slash
<span id="L4368" class="LineNr">4368 </span>  ]
<span id="L4369" class="LineNr">4369 </span>  run [
<span id="L4370" class="LineNr">4370 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4371" class="LineNr">4371 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L4372" class="LineNr">4372 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L4373" class="LineNr">4373 </span>  ]
<span id="L4374" class="LineNr">4374 </span>  screen-should-contain [
<span id="L4375" class="LineNr">4375 </span>   <span class="Constant"> .          .</span>
<span id="L4376" class="LineNr">4376 </span>   <span class="Constant"> .#? ab     .</span>
<span id="L4377" class="LineNr">4377 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L4378" class="LineNr">4378 </span>   <span class="Constant"> .          .</span>
<span id="L4379" class="LineNr">4379 </span>  ]
<span id="L4380" class="LineNr">4380 </span>  memory-should-contain [
<span id="L4381" class="LineNr">4381 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L4382" class="LineNr">4382 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>
<span id="L4383" class="LineNr">4383 </span>  ]
<span id="L4384" class="LineNr">4384 </span>  check-trace-count-for-label<span class="Constant"> 10</span>, <span class="Constant">[print-character]</span>
<span id="L4385" class="LineNr">4385 </span>  <span class="Comment"># toggle to uncomment</span>
<span id="L4386" class="LineNr">4386 </span>  $clear-trace
<span id="L4387" class="LineNr">4387 </span>  assume-console [
<span id="L4388" class="LineNr">4388 </span>    press ctrl-slash
<span id="L4389" class="LineNr">4389 </span>  ]
<span id="L4390" class="LineNr">4390 </span>  run [
<span id="L4391" class="LineNr">4391 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4392" class="LineNr">4392 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L4393" class="LineNr">4393 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L4394" class="LineNr">4394 </span>  ]
<span id="L4395" class="LineNr">4395 </span>  screen-should-contain [
<span id="L4396" class="LineNr">4396 </span>   <span class="Constant"> .          .</span>
<span id="L4397" class="LineNr">4397 </span>   <span class="Constant"> .ab        .</span>
<span id="L4398" class="LineNr">4398 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L4399" class="LineNr">4399 </span>   <span class="Constant"> .          .</span>
<span id="L4400" class="LineNr">4400 </span>  ]
<span id="L4401" class="LineNr">4401 </span>  check-trace-count-for-label<span class="Constant"> 10</span>, <span class="Constant">[print-character]</span>
<span id="L4402" class="LineNr">4402 </span>]
<span id="L4403" class="LineNr">4403 </span>
<span id="L4404" class="LineNr">4404 </span><span class="muScenario">scenario</span> editor-comments-almost-wrapping-line [
<span id="L4405" class="LineNr">4405 </span>  <span class="Constant">local-scope</span>
<span id="L4406" class="LineNr">4406 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L4407" class="LineNr">4407 </span>  <span class="Comment"># editor starts out with a non-wrapping line</span>
<span id="L4408" class="LineNr">4408 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abcd]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L4409" class="LineNr">4409 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L4410" class="LineNr">4410 </span>  screen-should-contain [
<span id="L4411" class="LineNr">4411 </span>   <span class="Constant"> .          .</span>
<span id="L4412" class="LineNr">4412 </span>   <span class="Constant"> .abcd      .</span>
<span id="L4413" class="LineNr">4413 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L4414" class="LineNr">4414 </span>   <span class="Constant"> .          .</span>
<span id="L4415" class="LineNr">4415 </span>  ]
<span id="L4416" class="LineNr">4416 </span>  $clear-trace
<span id="L4417" class="LineNr">4417 </span>  <span class="Comment"># on commenting the line is now wrapped</span>
<span id="L4418" class="LineNr">4418 </span>  assume-console [
<span id="L4419" class="LineNr">4419 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 7</span>
<span id="L4420" class="LineNr">4420 </span>    press ctrl-slash
<span id="L4421" class="LineNr">4421 </span>  ]
<span id="L4422" class="LineNr">4422 </span>  run [
<span id="L4423" class="LineNr">4423 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4424" class="LineNr">4424 </span>  ]
<span id="L4425" class="LineNr">4425 </span>  screen-should-contain [
<span id="L4426" class="LineNr">4426 </span>   <span class="Constant"> .          .</span>
<span id="L4427" class="LineNr">4427 </span>   <span class="Constant"> .#? a↩     .</span>
<span id="L4428" class="LineNr">4428 </span>   <span class="Constant"> .bcd       .</span>
<span id="L4429" class="LineNr">4429 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L4430" class="LineNr">4430 </span>   <span class="Constant"> .          .</span>
<span id="L4431" class="LineNr">4431 </span>  ]
<span id="L4432" class="LineNr">4432 </span>]
<span id="L4433" class="LineNr">4433 </span>
<span id="L4434" class="LineNr">4434 </span><span class="muScenario">scenario</span> editor-uncomments-just-wrapping-line [
<span id="L4435" class="LineNr">4435 </span>  <span class="Constant">local-scope</span>
<span id="L4436" class="LineNr">4436 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L4437" class="LineNr">4437 </span>  <span class="Comment"># editor starts out with a comment that wraps the line</span>
<span id="L4438" class="LineNr">4438 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[#? ab]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L4439" class="LineNr">4439 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L4440" class="LineNr">4440 </span>  screen-should-contain [
<span id="L4441" class="LineNr">4441 </span>   <span class="Constant"> .          .</span>
<span id="L4442" class="LineNr">4442 </span>   <span class="Constant"> .#? a↩     .</span>
<span id="L4443" class="LineNr">4443 </span>   <span class="Constant"> .b         .</span>
<span id="L4444" class="LineNr">4444 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L4445" class="LineNr">4445 </span>   <span class="Constant"> .          .</span>
<span id="L4446" class="LineNr">4446 </span>  ]
<span id="L4447" class="LineNr">4447 </span>  $clear-trace
<span id="L4448" class="LineNr">4448 </span>  <span class="Comment"># on uncommenting the line is no longer wrapped</span>
<span id="L4449" class="LineNr">4449 </span>  assume-console [
<span id="L4450" class="LineNr">4450 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 7</span>
<span id="L4451" class="LineNr">4451 </span>    press ctrl-slash
<span id="L4452" class="LineNr">4452 </span>  ]
<span id="L4453" class="LineNr">4453 </span>  run [
<span id="L4454" class="LineNr">4454 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4455" class="LineNr">4455 </span>  ]
<span id="L4456" class="LineNr">4456 </span>  screen-should-contain [
<span id="L4457" class="LineNr">4457 </span>   <span class="Constant"> .          .</span>
<span id="L4458" class="LineNr">4458 </span>   <span class="Constant"> .ab        .</span>
<span id="L4459" class="LineNr">4459 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L4460" class="LineNr">4460 </span>   <span class="Constant"> .          .</span>
<span id="L4461" class="LineNr">4461 </span>  ]
<span id="L4462" class="LineNr">4462 </span>]
</pre>
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<a href='https://github.com/akkartik/mu/blob/master/edit/003-shortcuts.mu'>https://github.com/akkartik/mu/blob/master/edit/003-shortcuts.mu</a>
<pre id='vimCodeElement'>
<span id="L1" class="LineNr">   1 </span><span class="SalientComment">## special shortcuts for manipulating the editor</span>
<span id="L2" class="LineNr">   2 </span><span class="Comment"># Some keys on the keyboard generate unicode characters, others generate</span>
<span id="L3" class="LineNr">   3 </span><span class="Comment"># terminfo key codes. We need to modify different places in the two cases.</span>
<span id="L4" class="LineNr">   4 </span>
<span id="L5" class="LineNr">   5 </span><span class="Comment"># tab - insert two spaces</span>
<span id="L6" class="LineNr">   6 </span>
<span id="L7" class="LineNr">   7 </span><span class="muScenario">scenario</span> editor-inserts-two-spaces-on-tab [
<span id="L8" class="LineNr">   8 </span>  <span class="Constant">local-scope</span>
<span id="L9" class="LineNr">   9 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L10" class="LineNr">  10 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[ab</span>
<span id="L11" class="LineNr">  11 </span><span class="Constant">cd]</span>
<span id="L12" class="LineNr">  12 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L13" class="LineNr">  13 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L14" class="LineNr">  14 </span>  $clear-trace
<span id="L15" class="LineNr">  15 </span>  assume-console [
<span id="L16" class="LineNr">  16 </span>    press tab
<span id="L17" class="LineNr">  17 </span>  ]
<span id="L18" class="LineNr">  18 </span>  run [
<span id="L19" class="LineNr">  19 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L20" class="LineNr">  20 </span>  ]
<span id="L21" class="LineNr">  21 </span>  screen-should-contain [
<span id="L22" class="LineNr">  22 </span>   <span class="Constant"> .          .</span>
<span id="L23" class="LineNr">  23 </span>   <span class="Constant"> .  ab      .</span>
<span id="L24" class="LineNr">  24 </span>   <span class="Constant"> .cd        .</span>
<span id="L25" class="LineNr">  25 </span>  ]
<span id="L26" class="LineNr">  26 </span>  <span class="Comment"># we render at most two editor rows worth (one row for each space)</span>
<span id="L27" class="LineNr">  27 </span>  check-trace-count-for-label-lesser-than<span class="Constant"> 10</span>, <span class="Constant">[print-character]</span>
<span id="L28" class="LineNr">  28 </span>]
<span id="L29" class="LineNr">  29 </span>
<span id="L30" class="LineNr">  30 </span><span class="muScenario">scenario</span> editor-inserts-two-spaces-and-wraps-line-on-tab [
<span id="L31" class="LineNr">  31 </span>  <span class="Constant">local-scope</span>
<span id="L32" class="LineNr">  32 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L33" class="LineNr">  33 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abcd]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L34" class="LineNr">  34 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L35" class="LineNr">  35 </span>  $clear-trace
<span id="L36" class="LineNr">  36 </span>  assume-console [
<span id="L37" class="LineNr">  37 </span>    press tab
<span id="L38" class="LineNr">  38 </span>  ]
<span id="L39" class="LineNr">  39 </span>  run [
<span id="L40" class="LineNr">  40 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L41" class="LineNr">  41 </span>  ]
<span id="L42" class="LineNr">  42 </span>  screen-should-contain [
<span id="L43" class="LineNr">  43 </span>   <span class="Constant"> .          .</span>
<span id="L44" class="LineNr">  44 </span>   <span class="Constant"> .  ab↩     .</span>
<span id="L45" class="LineNr">  45 </span>   <span class="Constant"> .cd        .</span>
<span id="L46" class="LineNr">  46 </span>  ]
<span id="L47" class="LineNr">  47 </span>  <span class="Comment"># we re-render the whole editor</span>
<span id="L48" class="LineNr">  48 </span>  check-trace-count-for-label-greater-than<span class="Constant"> 10</span>, <span class="Constant">[print-character]</span>
<span id="L49" class="LineNr">  49 </span>]
<span id="L50" class="LineNr">  50 </span>
<span id="L51" class="LineNr">  51 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L52" class="LineNr">  52 </span>  <span class="Delimiter">{</span>
<span id="L53" class="LineNr">  53 </span>    tab?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">9/tab</span>
<span id="L54" class="LineNr">  54 </span>    <span class="muControl">break-unless</span> tab?
<span id="L55" class="LineNr">  55 </span><span class="Constant">    &lt;begin-insert-character&gt;</span>
<span id="L56" class="LineNr">  56 </span>    <span class="Comment"># todo: decompose insert-at-cursor into editor update and screen update,</span>
<span id="L57" class="LineNr">  57 </span>    <span class="Comment"># so that 'tab' doesn't render the current line multiple times</span>
<span id="L58" class="LineNr">  58 </span>    <a href='002-typing.mu.html#L203'>insert-at-cursor</a> editor, <span class="Constant">32/space</span>, <a href='../081print.mu.html#L16'>screen</a>
<span id="L59" class="LineNr">  59 </span>    go-render? <span class="Special">&lt;-</span> <a href='002-typing.mu.html#L203'>insert-at-cursor</a> editor, <span class="Constant">32/space</span>, <a href='../081print.mu.html#L16'>screen</a>
<span id="L60" class="LineNr">  60 </span><span class="Constant">    &lt;end-insert-character&gt;</span>
<span id="L61" class="LineNr">  61 </span>   <span class="muControl"> return</span>
<span id="L62" class="LineNr">  62 </span>  <span class="Delimiter">}</span>
<span id="L63" class="LineNr">  63 </span>]
<span id="L64" class="LineNr">  64 </span>
<span id="L65" class="LineNr">  65 </span><span class="Comment"># backspace - delete character before cursor</span>
<span id="L66" class="LineNr">  66 </span>
<span id="L67" class="LineNr">  67 </span><span class="muScenario">scenario</span> editor-handles-backspace-key [
<span id="L68" class="LineNr">  68 </span>  <span class="Constant">local-scope</span>
<span id="L69" class="LineNr">  69 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L70" class="LineNr">  70 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abc]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L71" class="LineNr">  71 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L72" class="LineNr">  72 </span>  $clear-trace
<span id="L73" class="LineNr">  73 </span>  assume-console [
<span id="L74" class="LineNr">  74 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
<span id="L75" class="LineNr">  75 </span>    press backspace
<span id="L76" class="LineNr">  76 </span>  ]
<span id="L77" class="LineNr">  77 </span>  run [
<span id="L78" class="LineNr">  78 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L79" class="LineNr">  79 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L80" class="LineNr">  80 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L81" class="LineNr">  81 </span>  ]
<span id="L82" class="LineNr">  82 </span>  screen-should-contain [
<span id="L83" class="LineNr">  83 </span>   <span class="Constant"> .          .</span>
<span id="L84" class="LineNr">  84 </span>   <span class="Constant"> .bc        .</span>
<span id="L85" class="LineNr">  85 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L86" class="LineNr">  86 </span>   <span class="Constant"> .          .</span>
<span id="L87" class="LineNr">  87 </span>  ]
<span id="L88" class="LineNr">  88 </span>  memory-should-contain [
<span id="L89" class="LineNr">  89 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L90" class="LineNr">  90 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L91" class="LineNr">  91 </span>  ]
<span id="L92" class="LineNr">  92 </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="L93" class="LineNr">  93 </span>]
<span id="L94" class="LineNr">  94 </span>
<span id="L95" class="LineNr">  95 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L96" class="LineNr">  96 </span>  <span class="Delimiter">{</span>
<span id="L97" class="LineNr">  97 </span>    delete-previous-character?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">8/backspace</span>
<span id="L98" class="LineNr">  98 </span>    <span class="muControl">break-unless</span> delete-previous-character?
<span id="L99" class="LineNr">  99 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L99'>&lt;begin-backspace-character&gt;</a></span>
<span id="L100" class="LineNr"> 100 </span>    go-render?:bool, backspaced-cell:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L109'>delete-before-cursor</a> editor, <a href='../081print.mu.html#L16'>screen</a>
<span id="L101" class="LineNr"> 101 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L101'>&lt;end-backspace-character&gt;</a></span>
<span id="L102" class="LineNr"> 102 </span>   <span class="muControl"> return</span>
<span id="L103" class="LineNr"> 103 </span>  <span class="Delimiter">}</span>
<span id="L104" class="LineNr"> 104 </span>]
<span id="L105" class="LineNr"> 105 </span>
<span id="L106" class="LineNr"> 106 </span><span class="Comment"># return values:</span>
<span id="L107" class="LineNr"> 107 </span><span class="Comment">#   go-render? - whether caller needs to update the screen</span>
<span id="L108" class="LineNr"> 108 </span><span class="Comment">#   backspaced-cell - value deleted (or 0 if nothing was deleted) so we can save it for undo, etc.</span>
<span id="L109" class="LineNr"> 109 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L109'>delete-before-cursor</a> editor:&amp;:editor, <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a><span class="muRecipe"> -&gt; </span>go-render?:bool, backspaced-cell:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char, editor:&amp;:editor, <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a> [
<span id="L110" class="LineNr"> 110 </span>  <span class="Constant">local-scope</span>
<span id="L111" class="LineNr"> 111 </span>  <span class="Constant">load-inputs</span>
<span id="L112" class="LineNr"> 112 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L113" class="LineNr"> 113 </span>  data:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
<span id="L114" class="LineNr"> 114 </span>  <span class="Comment"># if at start of text (before-cursor at § sentinel), return</span>
<span id="L115" class="LineNr"> 115 </span>  <a href='../065duplex_list.mu.html#L38'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L38'>prev</a> before-cursor
<span id="L116" class="LineNr"> 116 </span>  <span class="muControl">return-unless</span> <a href='../065duplex_list.mu.html#L38'>prev</a>,<span class="Constant"> false/no-more-render, null/nothing-deleted</span>
<span id="L117" class="LineNr"> 117 </span>  trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[delete-before-cursor]</span>
<span id="L118" class="LineNr"> 118 </span>  original-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L119" class="LineNr"> 119 </span>  scroll?:bool <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L156'>move-cursor-coordinates-left</a> editor
<span id="L120" class="LineNr"> 120 </span>  backspaced-cell:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy before-cursor
<span id="L121" class="LineNr"> 121 </span>  data <span class="Special">&lt;-</span> remove before-cursor, data  <span class="Comment"># will also neatly trim next/prev pointers in backspaced-cell/before-cursor</span>
<span id="L122" class="LineNr"> 122 </span>  before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L38'>prev</a>
<span id="L123" class="LineNr"> 123 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L124" class="LineNr"> 124 </span>  <span class="muControl">return-if</span> scroll?,<span class="Constant"> true/go-render</span>
<span id="L125" class="LineNr"> 125 </span>  <a href='../081print.mu.html#L768'>screen-width</a>:num <span class="Special">&lt;-</span> <a href='../081print.mu.html#L768'>screen-width</a> <a href='../081print.mu.html#L16'>screen</a>
<span id="L126" class="LineNr"> 126 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L127" class="LineNr"> 127 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L128" class="LineNr"> 128 </span>  <span class="Comment"># did we just backspace over a newline?</span>
<span id="L129" class="LineNr"> 129 </span>  same-row?:bool <span class="Special">&lt;-</span> equal cursor-row, original-row
<span id="L130" class="LineNr"> 130 </span>  <span class="muControl">return-unless</span> same-row?,<span class="Constant"> true/go-render</span>
<span id="L131" class="LineNr"> 131 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L132" class="LineNr"> 132 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L133" class="LineNr"> 133 </span>  curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-cursor
<span id="L134" class="LineNr"> 134 </span>  <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> move-cursor <a href='../081print.mu.html#L16'>screen</a>, cursor-row, cursor-column
<span id="L135" class="LineNr"> 135 </span>  curr-column:num <span class="Special">&lt;-</span> copy cursor-column
<span id="L136" class="LineNr"> 136 </span>  <span class="Delimiter">{</span>
<span id="L137" class="LineNr"> 137 </span>    <span class="Comment"># hit right margin? give up and let caller render</span>
<span id="L138" class="LineNr"> 138 </span>    at-right?:bool <span class="Special">&lt;-</span> greater-or-equal curr-column, right
<span id="L139" class="LineNr"> 139 </span>    <span class="muControl">return-if</span> at-right?,<span class="Constant"> true/go-render</span>
<span id="L140" class="LineNr"> 140 </span>    <span class="muControl">break-unless</span> curr
<span id="L141" class="LineNr"> 141 </span>    <span class="Comment"># newline? done.</span>
<span id="L142" class="LineNr"> 142 </span>    currc:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
<span id="L143" class="LineNr"> 143 </span>    at-newline?:bool <span class="Special">&lt;-</span> equal currc, <span class="Constant">10/newline</span>
<span id="L144" class="LineNr"> 144 </span>    <span class="muControl">break-if</span> at-newline?
<span id="L145" class="LineNr"> 145 </span>    <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> print <a href='../081print.mu.html#L16'>screen</a>, currc
<span id="L146" class="LineNr"> 146 </span>    curr-column <span class="Special">&lt;-</span> add curr-column,<span class="Constant"> 1</span>
<span id="L147" class="LineNr"> 147 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> curr
<span id="L148" class="LineNr"> 148 </span>   <span class="muControl"> loop</span>
<span id="L149" class="LineNr"> 149 </span>  <span class="Delimiter">}</span>
<span id="L150" class="LineNr"> 150 </span>  <span class="Comment"># we're guaranteed not to be at the right margin</span>
<span id="L151" class="LineNr"> 151 </span>  space:char <span class="Special">&lt;-</span> copy <span class="Constant">32/space</span>
<span id="L152" class="LineNr"> 152 </span>  <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> print <a href='../081print.mu.html#L16'>screen</a>, space
<span id="L153" class="LineNr"> 153 </span>  go-render? <span class="Special">&lt;-</span> copy<span class="Constant"> false</span>
<span id="L154" class="LineNr"> 154 </span>]
<span id="L155" class="LineNr"> 155 </span>
<span id="L156" class="LineNr"> 156 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L156'>move-cursor-coordinates-left</a> editor:&amp;:editor<span class="muRecipe"> -&gt; </span>go-render?:bool, editor:&amp;:editor [
<span id="L157" class="LineNr"> 157 </span>  <span class="Constant">local-scope</span>
<span id="L158" class="LineNr"> 158 </span>  <span class="Constant">load-inputs</span>
<span id="L159" class="LineNr"> 159 </span>  go-render?:bool <span class="Special">&lt;-</span> copy<span class="Constant"> false</span>
<span id="L160" class="LineNr"> 160 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L161" class="LineNr"> 161 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L162" class="LineNr"> 162 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L163" class="LineNr"> 163 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L164" class="LineNr"> 164 </span>  <span class="Comment"># if not at left margin, move one character left</span>
<span id="L165" class="LineNr"> 165 </span>  <span class="Delimiter">{</span>
<span id="L166" class="LineNr"> 166 </span>    at-left-margin?:bool <span class="Special">&lt;-</span> equal cursor-column, left
<span id="L167" class="LineNr"> 167 </span>    <span class="muControl">break-if</span> at-left-margin?
<span id="L168" class="LineNr"> 168 </span>    trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[decrementing cursor column]</span>
<span id="L169" class="LineNr"> 169 </span>    cursor-column <span class="Special">&lt;-</span> subtract cursor-column,<span class="Constant"> 1</span>
<span id="L170" class="LineNr"> 170 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L171" class="LineNr"> 171 </span>   <span class="muControl"> return</span>
<span id="L172" class="LineNr"> 172 </span>  <span class="Delimiter">}</span>
<span id="L173" class="LineNr"> 173 </span>  <span class="Comment"># if at left margin, we must move to previous row:</span>
<span id="L174" class="LineNr"> 174 </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="L175" class="LineNr"> 175 </span>  <span class="Delimiter">{</span>
<span id="L176" class="LineNr"> 176 </span>    <span class="muControl">break-if</span> top-of-screen?
<span id="L177" class="LineNr"> 177 </span>    cursor-row <span class="Special">&lt;-</span> subtract cursor-row,<span class="Constant"> 1</span>
<span id="L178" class="LineNr"> 178 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
<span id="L179" class="LineNr"> 179 </span>  <span class="Delimiter">}</span>
<span id="L180" class="LineNr"> 180 </span>  <span class="Delimiter">{</span>
<span id="L181" class="LineNr"> 181 </span>    <span class="muControl">break-unless</span> top-of-screen?
<span id="L182" class="LineNr"> 182 </span><span class="Constant">    &lt;scroll-up&gt;</span>
<span id="L183" class="LineNr"> 183 </span>    go-render? <span class="Special">&lt;-</span> copy<span class="Constant"> true</span>
<span id="L184" class="LineNr"> 184 </span>  <span class="Delimiter">}</span>
<span id="L185" class="LineNr"> 185 </span>  <span class="Delimiter">{</span>
<span id="L186" class="LineNr"> 186 </span>    <span class="Comment"># case 1: if previous character was newline, figure out how long the previous line is</span>
<span id="L187" class="LineNr"> 187 </span>    previous-character:char <span class="Special">&lt;-</span> get *before-cursor, <span class="Constant">value:offset</span>
<span id="L188" class="LineNr"> 188 </span>    previous-character-is-newline?:bool <span class="Special">&lt;-</span> equal previous-character, <span class="Constant">10/newline</span>
<span id="L189" class="LineNr"> 189 </span>    <span class="muControl">break-unless</span> previous-character-is-newline?
<span id="L190" class="LineNr"> 190 </span>    <span class="Comment"># compute length of previous line</span>
<span id="L191" class="LineNr"> 191 </span>    trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[switching to previous line]</span>
<span id="L192" class="LineNr"> 192 </span>    d:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
<span id="L193" class="LineNr"> 193 </span>    end-of-line:num <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L219'>previous-line-length</a> before-cursor, d
<span id="L194" class="LineNr"> 194 </span>    right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L195" class="LineNr"> 195 </span>    width:num <span class="Special">&lt;-</span> subtract right, left
<span id="L196" class="LineNr"> 196 </span>    wrap?:bool <span class="Special">&lt;-</span> greater-than end-of-line, width
<span id="L197" class="LineNr"> 197 </span>    <span class="Delimiter">{</span>
<span id="L198" class="LineNr"> 198 </span>      <span class="muControl">break-unless</span> wrap?
<span id="L199" class="LineNr"> 199 </span>      _, column-offset:num <span class="Special">&lt;-</span> divide-with-remainder end-of-line, width
<span id="L200" class="LineNr"> 200 </span>      cursor-column <span class="Special">&lt;-</span> add left, column-offset
<span id="L201" class="LineNr"> 201 </span>      *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L202" class="LineNr"> 202 </span>    <span class="Delimiter">}</span>
<span id="L203" class="LineNr"> 203 </span>    <span class="Delimiter">{</span>
<span id="L204" class="LineNr"> 204 </span>      <span class="muControl">break-if</span> wrap?
<span id="L205" class="LineNr"> 205 </span>      cursor-column <span class="Special">&lt;-</span> add left, end-of-line
<span id="L206" class="LineNr"> 206 </span>      *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L207" class="LineNr"> 207 </span>    <span class="Delimiter">}</span>
<span id="L208" class="LineNr"> 208 </span>   <span class="muControl"> return</span>
<span id="L209" class="LineNr"> 209 </span>  <span class="Delimiter">}</span>
<span id="L210" class="LineNr"> 210 </span>  <span class="Comment"># case 2: if previous-character was not newline, we're just at a wrapped line</span>
<span id="L211" class="LineNr"> 211 </span>  trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[wrapping to previous line]</span>
<span id="L212" class="LineNr"> 212 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L213" class="LineNr"> 213 </span>  cursor-column <span class="Special">&lt;-</span> subtract right,<span class="Constant"> 1</span>  <span class="Comment"># leave room for wrap icon</span>
<span id="L214" class="LineNr"> 214 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L215" class="LineNr"> 215 </span>]
<span id="L216" class="LineNr"> 216 </span>
<span id="L217" class="LineNr"> 217 </span><span class="Comment"># takes a pointer 'curr' into the doubly-linked list and its sentinel, counts</span>
<span id="L218" class="LineNr"> 218 </span><span class="Comment"># the length of the previous line before the 'curr' pointer.</span>
<span id="L219" class="LineNr"> 219 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L219'>previous-line-length</a> curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char, start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char<span class="muRecipe"> -&gt; </span>result:num [
<span id="L220" class="LineNr"> 220 </span>  <span class="Constant">local-scope</span>
<span id="L221" class="LineNr"> 221 </span>  <span class="Constant">load-inputs</span>
<span id="L222" class="LineNr"> 222 </span>  result:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
<span id="L223" class="LineNr"> 223 </span>  <span class="muControl">return-unless</span> curr
<span id="L224" class="LineNr"> 224 </span>  at-start?:bool <span class="Special">&lt;-</span> equal curr, start
<span id="L225" class="LineNr"> 225 </span>  <span class="muControl">return-if</span> at-start?
<span id="L226" class="LineNr"> 226 </span>  <span class="Delimiter">{</span>
<span id="L227" class="LineNr"> 227 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L38'>prev</a> curr
<span id="L228" class="LineNr"> 228 </span>    <span class="muControl">break-unless</span> curr
<span id="L229" class="LineNr"> 229 </span>    at-start?:bool <span class="Special">&lt;-</span> equal curr, start
<span id="L230" class="LineNr"> 230 </span>    <span class="muControl">break-if</span> at-start?
<span id="L231" class="LineNr"> 231 </span>    c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
<span id="L232" class="LineNr"> 232 </span>    at-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
<span id="L233" class="LineNr"> 233 </span>    <span class="muControl">break-if</span> at-newline?
<span id="L234" class="LineNr"> 234 </span>    result <span class="Special">&lt;-</span> add result,<span class="Constant"> 1</span>
<span id="L235" class="LineNr"> 235 </span>   <span class="muControl"> loop</span>
<span id="L236" class="LineNr"> 236 </span>  <span class="Delimiter">}</span>
<span id="L237" class="LineNr"> 237 </span>]
<span id="L238" class="LineNr"> 238 </span>
<span id="L239" class="LineNr"> 239 </span><span class="muScenario">scenario</span> editor-clears-last-line-on-backspace [
<span id="L240" class="LineNr"> 240 </span>  <span class="Constant">local-scope</span>
<span id="L241" class="LineNr"> 241 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L242" class="LineNr"> 242 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[ab</span>
<span id="L243" class="LineNr"> 243 </span><span class="Constant">cd]</span>
<span id="L244" class="LineNr"> 244 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L245" class="LineNr"> 245 </span>  assume-console [
<span id="L246" class="LineNr"> 246 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
<span id="L247" class="LineNr"> 247 </span>    press backspace
<span id="L248" class="LineNr"> 248 </span>  ]
<span id="L249" class="LineNr"> 249 </span>  run [
<span id="L250" class="LineNr"> 250 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L251" class="LineNr"> 251 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L252" class="LineNr"> 252 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L253" class="LineNr"> 253 </span>  ]
<span id="L254" class="LineNr"> 254 </span>  screen-should-contain [
<span id="L255" class="LineNr"> 255 </span>   <span class="Constant"> .          .</span>
<span id="L256" class="LineNr"> 256 </span>   <span class="Constant"> .abcd      .</span>
<span id="L257" class="LineNr"> 257 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L258" class="LineNr"> 258 </span>   <span class="Constant"> .          .</span>
<span id="L259" class="LineNr"> 259 </span>  ]
<span id="L260" class="LineNr"> 260 </span>  memory-should-contain [
<span id="L261" class="LineNr"> 261 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L262" class="LineNr"> 262 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L263" class="LineNr"> 263 </span>  ]
<span id="L264" class="LineNr"> 264 </span>]
<span id="L265" class="LineNr"> 265 </span>
<span id="L266" class="LineNr"> 266 </span><span class="muScenario">scenario</span> editor-joins-and-wraps-lines-on-backspace [
<span id="L267" class="LineNr"> 267 </span>  <span class="Constant">local-scope</span>
<span id="L268" class="LineNr"> 268 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L269" class="LineNr"> 269 </span>  <span class="Comment"># initialize editor with two long-ish but non-wrapping lines</span>
<span id="L270" class="LineNr"> 270 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc def</span>
<span id="L271" class="LineNr"> 271 </span><span class="Constant">ghi jkl]</span>
<span id="L272" class="LineNr"> 272 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L273" class="LineNr"> 273 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L274" class="LineNr"> 274 </span>  $clear-trace
<span id="L275" class="LineNr"> 275 </span>  <span class="Comment"># position the cursor at the start of the second and hit backspace</span>
<span id="L276" class="LineNr"> 276 </span>  assume-console [
<span id="L277" class="LineNr"> 277 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
<span id="L278" class="LineNr"> 278 </span>    press backspace
<span id="L279" class="LineNr"> 279 </span>  ]
<span id="L280" class="LineNr"> 280 </span>  run [
<span id="L281" class="LineNr"> 281 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L282" class="LineNr"> 282 </span>  ]
<span id="L283" class="LineNr"> 283 </span>  <span class="Comment"># resulting single line should wrap correctly</span>
<span id="L284" class="LineNr"> 284 </span>  screen-should-contain [
<span id="L285" class="LineNr"> 285 </span>   <span class="Constant"> .          .</span>
<span id="L286" class="LineNr"> 286 </span>   <span class="Constant"> .abc defgh↩.</span>
<span id="L287" class="LineNr"> 287 </span>   <span class="Constant"> .i jkl     .</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="L290" class="LineNr"> 290 </span>  ]
<span id="L291" class="LineNr"> 291 </span>]
<span id="L292" class="LineNr"> 292 </span>
<span id="L293" class="LineNr"> 293 </span><span class="muScenario">scenario</span> editor-wraps-long-lines-on-backspace [
<span id="L294" class="LineNr"> 294 </span>  <span class="Constant">local-scope</span>
<span id="L295" class="LineNr"> 295 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L296" class="LineNr"> 296 </span>  <span class="Comment"># initialize editor in part of the screen with a long line</span>
<span id="L297" class="LineNr"> 297 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abc def ghij]</span>, <span class="Constant">0/left</span>, <span class="Constant">8/right</span>
<span id="L298" class="LineNr"> 298 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L299" class="LineNr"> 299 </span>  <span class="Comment"># confirm that it wraps</span>
<span id="L300" class="LineNr"> 300 </span>  screen-should-contain [
<span id="L301" class="LineNr"> 301 </span>   <span class="Constant"> .          .</span>
<span id="L302" class="LineNr"> 302 </span>   <span class="Constant"> .abc def↩  .</span>
<span id="L303" class="LineNr"> 303 </span>   <span class="Constant"> . ghij     .</span>
<span id="L304" class="LineNr"> 304 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌  .</span>
<span id="L305" class="LineNr"> 305 </span>  ]
<span id="L306" class="LineNr"> 306 </span>  $clear-trace
<span id="L307" class="LineNr"> 307 </span>  <span class="Comment"># position the cursor somewhere in the middle of the top screen line and hit backspace</span>
<span id="L308" class="LineNr"> 308 </span>  assume-console [
<span id="L309" class="LineNr"> 309 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 4</span>
<span id="L310" class="LineNr"> 310 </span>    press backspace
<span id="L311" class="LineNr"> 311 </span>  ]
<span id="L312" class="LineNr"> 312 </span>  run [
<span id="L313" class="LineNr"> 313 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L314" class="LineNr"> 314 </span>  ]
<span id="L315" class="LineNr"> 315 </span>  <span class="Comment"># resulting single line should wrap correctly and not overflow its bounds</span>
<span id="L316" class="LineNr"> 316 </span>  screen-should-contain [
<span id="L317" class="LineNr"> 317 </span>   <span class="Constant"> .          .</span>
<span id="L318" class="LineNr"> 318 </span>   <span class="Constant"> .abcdef ↩  .</span>
<span id="L319" class="LineNr"> 319 </span>   <span class="Constant"> .ghij      .</span>
<span id="L320" class="LineNr"> 320 </span>   <span class="Constant"> .╌╌╌╌╌╌╌╌  .</span>
<span id="L321" class="LineNr"> 321 </span>   <span class="Constant"> .          .</span>
<span id="L322" class="LineNr"> 322 </span>  ]
<span id="L323" class="LineNr"> 323 </span>]
<span id="L324" class="LineNr"> 324 </span>
<span id="L325" class="LineNr"> 325 </span><span class="Comment"># delete - delete character at cursor</span>
<span id="L326" class="LineNr"> 326 </span>
<span id="L327" class="LineNr"> 327 </span><span class="muScenario">scenario</span> editor-handles-delete-key [
<span id="L328" class="LineNr"> 328 </span>  <span class="Constant">local-scope</span>
<span id="L329" class="LineNr"> 329 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L330" class="LineNr"> 330 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abc]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L331" class="LineNr"> 331 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L332" class="LineNr"> 332 </span>  $clear-trace
<span id="L333" class="LineNr"> 333 </span>  assume-console [
<span id="L334" class="LineNr"> 334 </span>    press delete
<span id="L335" class="LineNr"> 335 </span>  ]
<span id="L336" class="LineNr"> 336 </span>  run [
<span id="L337" class="LineNr"> 337 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L338" class="LineNr"> 338 </span>  ]
<span id="L339" class="LineNr"> 339 </span>  screen-should-contain [
<span id="L340" class="LineNr"> 340 </span>   <span class="Constant"> .          .</span>
<span id="L341" class="LineNr"> 341 </span>   <span class="Constant"> .bc        .</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 id="L345" class="LineNr"> 345 </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="L346" class="LineNr"> 346 </span>  $clear-trace
<span id="L347" class="LineNr"> 347 </span>  assume-console [
<span id="L348" class="LineNr"> 348 </span>    press delete
<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#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L352" class="LineNr"> 352 </span>  ]
<span id="L353" class="LineNr"> 353 </span>  screen-should-contain [
<span id="L354" class="LineNr"> 354 </span>   <span class="Constant"> .          .</span>
<span id="L355" class="LineNr"> 355 </span>   <span class="Constant"> .c         .</span>
<span id="L356" class="LineNr"> 356 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L357" class="LineNr"> 357 </span>   <span class="Constant"> .          .</span>
<span id="L358" class="LineNr"> 358 </span>  ]
<span id="L359" class="LineNr"> 359 </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="L360" class="LineNr"> 360 </span>]
<span id="L361" class="LineNr"> 361 </span>
<span id="L362" class="LineNr"> 362 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L199'>&lt;handle-special-key&gt;</a></span> [
<span id="L363" class="LineNr"> 363 </span>  <span class="Delimiter">{</span>
<span id="L364" class="LineNr"> 364 </span>    delete-next-character?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65522/delete</span>
<span id="L365" class="LineNr"> 365 </span>    <span class="muControl">break-unless</span> delete-next-character?
<span id="L366" class="LineNr"> 366 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L366'>&lt;begin-delete-character&gt;</a></span>
<span id="L367" class="LineNr"> 367 </span>    go-render?:bool, deleted-cell:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L373'>delete-at-cursor</a> editor, <a href='../081print.mu.html#L16'>screen</a>
<span id="L368" class="LineNr"> 368 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L368'>&lt;end-delete-character&gt;</a></span>
<span id="L369" class="LineNr"> 369 </span>   <span class="muControl"> return</span>
<span id="L370" class="LineNr"> 370 </span>  <span class="Delimiter">}</span>
<span id="L371" class="LineNr"> 371 </span>]
<span id="L372" class="LineNr"> 372 </span>
<span id="L373" class="LineNr"> 373 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L373'>delete-at-cursor</a> editor:&amp;:editor, <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a><span class="muRecipe"> -&gt; </span>go-render?:bool, deleted-cell:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char, editor:&amp;:editor, <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a> [
<span id="L374" class="LineNr"> 374 </span>  <span class="Constant">local-scope</span>
<span id="L375" class="LineNr"> 375 </span>  <span class="Constant">load-inputs</span>
<span id="L376" class="LineNr"> 376 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L377" class="LineNr"> 377 </span>  data:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
<span id="L378" class="LineNr"> 378 </span>  deleted-cell:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-cursor
<span id="L379" class="LineNr"> 379 </span>  <span class="muControl">return-unless</span> deleted-cell,<span class="Constant"> false/don't-render</span>
<span id="L380" class="LineNr"> 380 </span>  currc:char <span class="Special">&lt;-</span> get *deleted-cell, <span class="Constant">value:offset</span>
<span id="L381" class="LineNr"> 381 </span>  data <span class="Special">&lt;-</span> remove deleted-cell, data
<span id="L382" class="LineNr"> 382 </span>  deleted-newline?:bool <span class="Special">&lt;-</span> equal currc, <span class="Constant">10/newline</span>
<span id="L383" class="LineNr"> 383 </span>  <span class="muControl">return-if</span> deleted-newline?,<span class="Constant"> true/go-render</span>
<span id="L384" class="LineNr"> 384 </span>  <span class="Comment"># wasn't a newline? render rest of line</span>
<span id="L385" class="LineNr"> 385 </span>  curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-cursor  <span class="Comment"># refresh after remove above</span>
<span id="L386" class="LineNr"> 386 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L387" class="LineNr"> 387 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L388" class="LineNr"> 388 </span>  <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> move-cursor <a href='../081print.mu.html#L16'>screen</a>, cursor-row, cursor-column
<span id="L389" class="LineNr"> 389 </span>  curr-column:num <span class="Special">&lt;-</span> copy cursor-column
<span id="L390" class="LineNr"> 390 </span>  <a href='../081print.mu.html#L768'>screen-width</a>:num <span class="Special">&lt;-</span> <a href='../081print.mu.html#L768'>screen-width</a> <a href='../081print.mu.html#L16'>screen</a>
<span id="L391" class="LineNr"> 391 </span>  <span class="Delimiter">{</span>
<span id="L392" class="LineNr"> 392 </span>    <span class="Comment"># hit right margin? give up and let caller render</span>
<span id="L393" class="LineNr"> 393 </span>    at-right?:bool <span class="Special">&lt;-</span> greater-or-equal curr-column, <a href='../081print.mu.html#L768'>screen-width</a>
<span id="L394" class="LineNr"> 394 </span>    <span class="muControl">return-if</span> at-right?,<span class="Constant"> true/go-render</span>
<span id="L395" class="LineNr"> 395 </span>    <span class="muControl">break-unless</span> curr
<span id="L396" class="LineNr"> 396 </span>    currc:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
<span id="L397" class="LineNr"> 397 </span>    at-newline?:bool <span class="Special">&lt;-</span> equal currc, <span class="Constant">10/newline</span>
<span id="L398" class="LineNr"> 398 </span>    <span class="muControl">break-if</span> at-newline?
<span id="L399" class="LineNr"> 399 </span>    <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> print <a href='../081print.mu.html#L16'>screen</a>, currc
<span id="L400" class="LineNr"> 400 </span>    curr-column <span class="Special">&lt;-</span> add curr-column,<span class="Constant"> 1</span>
<span id="L401" class="LineNr"> 401 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> curr
<span id="L402" class="LineNr"> 402 </span>   <span class="muControl"> loop</span>
<span id="L403" class="LineNr"> 403 </span>  <span class="Delimiter">}</span>
<span id="L404" class="LineNr"> 404 </span>  <span class="Comment"># we're guaranteed not to be at the right margin</span>
<span id="L405" class="LineNr"> 405 </span>  space:char <span class="Special">&lt;-</span> copy <span class="Constant">32/space</span>
<span id="L406" class="LineNr"> 406 </span>  <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> print <a href='../081print.mu.html#L16'>screen</a>, space
<span id="L407" class="LineNr"> 407 </span>  go-render? <span class="Special">&lt;-</span> copy<span class="Constant"> false</span>
<span id="L408" class="LineNr"> 408 </span>]
<span id="L409" class="LineNr"> 409 </span>
<span id="L410" class="LineNr"> 410 </span><span class="Comment"># right arrow</span>
<span id="L411" class="LineNr"> 411 </span>
<span id="L412" class="LineNr"> 412 </span><span class="muScenario">scenario</span> editor-moves-cursor-right-with-key [
<span id="L413" class="LineNr"> 413 </span>  <span class="Constant">local-scope</span>
<span id="L414" class="LineNr"> 414 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L415" class="LineNr"> 415 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abc]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L416" class="LineNr"> 416 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L417" class="LineNr"> 417 </span>  $clear-trace
<span id="L418" class="LineNr"> 418 </span>  assume-console [
<span id="L419" class="LineNr"> 419 </span>    press right-arrow
<span id="L420" class="LineNr"> 420 </span>    type <span class="Constant">[0]</span>
<span id="L421" class="LineNr"> 421 </span>  ]
<span id="L422" class="LineNr"> 422 </span>  run [
<span id="L423" class="LineNr"> 423 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L424" class="LineNr"> 424 </span>  ]
<span id="L425" class="LineNr"> 425 </span>  screen-should-contain [
<span id="L426" class="LineNr"> 426 </span>   <span class="Constant"> .          .</span>
<span id="L427" class="LineNr"> 427 </span>   <span class="Constant"> .a0bc      .</span>
<span id="L428" class="LineNr"> 428 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L429" class="LineNr"> 429 </span>   <span class="Constant"> .          .</span>
<span id="L430" class="LineNr"> 430 </span>  ]
<span id="L431" class="LineNr"> 431 </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="L432" class="LineNr"> 432 </span>]
<span id="L433" class="LineNr"> 433 </span>
<span id="L434" class="LineNr"> 434 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L199'>&lt;handle-special-key&gt;</a></span> [
<span id="L435" class="LineNr"> 435 </span>  <span class="Delimiter">{</span>
<span id="L436" class="LineNr"> 436 </span>    move-to-next-character?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65514/right-arrow</span>
<span id="L437" class="LineNr"> 437 </span>    <span class="muControl">break-unless</span> move-to-next-character?
<span id="L438" class="LineNr"> 438 </span>    <span class="Comment"># if not at end of text</span>
<span id="L439" class="LineNr"> 439 </span>    next-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-cursor
<span id="L440" class="LineNr"> 440 </span>    <span class="muControl">break-unless</span> next-cursor
<span id="L441" class="LineNr"> 441 </span>    <span class="Comment"># scan to next character</span>
<span id="L442" class="LineNr"> 442 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L443" class="LineNr"> 443 </span>    before-cursor <span class="Special">&lt;-</span> copy next-cursor
<span id="L444" class="LineNr"> 444 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L445" class="LineNr"> 445 </span>    go-render?:bool <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L453'>move-cursor-coordinates-right</a> editor, <a href='../081print.mu.html#L782'>screen-height</a>
<span id="L446" class="LineNr"> 446 </span>    <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> move-cursor <a href='../081print.mu.html#L16'>screen</a>, cursor-row, cursor-column
<span id="L447" class="LineNr"> 447 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">2/right-arrow</span>
<span id="L448" class="LineNr"> 448 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L449" class="LineNr"> 449 </span>   <span class="muControl"> return</span>
<span id="L450" class="LineNr"> 450 </span>  <span class="Delimiter">}</span>
<span id="L451" class="LineNr"> 451 </span>]
<span id="L452" class="LineNr"> 452 </span>
<span id="L453" class="LineNr"> 453 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L453'>move-cursor-coordinates-right</a> editor:&amp;:editor, <a href='../081print.mu.html#L782'>screen-height</a>:num<span class="muRecipe"> -&gt; </span>go-render?:bool, editor:&amp;:editor [
<span id="L454" class="LineNr"> 454 </span>  <span class="Constant">local-scope</span>
<span id="L455" class="LineNr"> 455 </span>  <span class="Constant">load-inputs</span>
<span id="L456" class="LineNr"> 456 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor <span class="Constant">before-cursor:offset</span>
<span id="L457" class="LineNr"> 457 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L458" class="LineNr"> 458 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L459" class="LineNr"> 459 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L460" class="LineNr"> 460 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L461" class="LineNr"> 461 </span>  <span class="Comment"># if crossed a newline, move cursor to start of next row</span>
<span id="L462" class="LineNr"> 462 </span>  <span class="Delimiter">{</span>
<span id="L463" class="LineNr"> 463 </span>    old-cursor-character:char <span class="Special">&lt;-</span> get *before-cursor, <span class="Constant">value:offset</span>
<span id="L464" class="LineNr"> 464 </span>    was-at-newline?:bool <span class="Special">&lt;-</span> equal old-cursor-character, <span class="Constant">10/newline</span>
<span id="L465" class="LineNr"> 465 </span>    <span class="muControl">break-unless</span> was-at-newline?
<span id="L466" class="LineNr"> 466 </span>    cursor-row <span class="Special">&lt;-</span> add cursor-row,<span class="Constant"> 1</span>
<span id="L467" class="LineNr"> 467 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
<span id="L468" class="LineNr"> 468 </span>    cursor-column <span class="Special">&lt;-</span> copy left
<span id="L469" class="LineNr"> 469 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L470" class="LineNr"> 470 </span>    below-screen?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-row, <a href='../081print.mu.html#L782'>screen-height</a>  <span class="Comment"># must be equal</span>
<span id="L471" class="LineNr"> 471 </span>    <span class="muControl">return-unless</span> below-screen?,<span class="Constant"> false/don't-render</span>
<span id="L472" class="LineNr"> 472 </span><span class="Constant">    &lt;scroll-down&gt;</span>
<span id="L473" class="LineNr"> 473 </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="L474" class="LineNr"> 474 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
<span id="L475" class="LineNr"> 475 </span>   <span class="muControl"> return</span><span class="Constant"> true/go-render</span>
<span id="L476" class="LineNr"> 476 </span>  <span class="Delimiter">}</span>
<span id="L477" class="LineNr"> 477 </span>  <span class="Comment"># if the line wraps, move cursor to start of next row</span>
<span id="L478" class="LineNr"> 478 </span>  <span class="Delimiter">{</span>
<span id="L479" class="LineNr"> 479 </span>    <span class="Comment"># if we're at the column just before the wrap indicator</span>
<span id="L480" class="LineNr"> 480 </span>    wrap-column:num <span class="Special">&lt;-</span> subtract right,<span class="Constant"> 1</span>
<span id="L481" class="LineNr"> 481 </span>    at-wrap?:bool <span class="Special">&lt;-</span> equal cursor-column, wrap-column
<span id="L482" class="LineNr"> 482 </span>    <span class="muControl">break-unless</span> at-wrap?
<span id="L483" class="LineNr"> 483 </span>    <span class="Comment"># and if next character isn't newline</span>
<span id="L484" class="LineNr"> 484 </span>    <a href='../065duplex_list.mu.html#L31'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-cursor
<span id="L485" class="LineNr"> 485 </span>    <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L31'>next</a>
<span id="L486" class="LineNr"> 486 </span>    next-character:char <span class="Special">&lt;-</span> get *next, <span class="Constant">value:offset</span>
<span id="L487" class="LineNr"> 487 </span>    newline?:bool <span class="Special">&lt;-</span> equal next-character, <span class="Constant">10/newline</span>
<span id="L488" class="LineNr"> 488 </span>    <span class="muControl">break-if</span> newline?
<span id="L489" class="LineNr"> 489 </span>    cursor-row <span class="Special">&lt;-</span> add cursor-row,<span class="Constant"> 1</span>
<span id="L490" class="LineNr"> 490 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
<span id="L491" class="LineNr"> 491 </span>    cursor-column <span class="Special">&lt;-</span> copy left
<span id="L492" class="LineNr"> 492 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L493" class="LineNr"> 493 </span>    below-screen?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-row, <a href='../081print.mu.html#L782'>screen-height</a>  <span class="Comment"># must be equal</span>
<span id="L494" class="LineNr"> 494 </span>    <span class="muControl">return-unless</span> below-screen?,<span class="Constant"> false/no-more-render</span>
<span id="L495" class="LineNr"> 495 </span><span class="Constant">    &lt;scroll-down&gt;</span>
<span id="L496" class="LineNr"> 496 </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="L497" class="LineNr"> 497 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
<span id="L498" class="LineNr"> 498 </span>   <span class="muControl"> return</span><span class="Constant"> true/go-render</span>
<span id="L499" class="LineNr"> 499 </span>  <span class="Delimiter">}</span>
<span id="L500" class="LineNr"> 500 </span>  <span class="Comment"># otherwise move cursor one character right</span>
<span id="L501" class="LineNr"> 501 </span>  cursor-column <span class="Special">&lt;-</span> add cursor-column,<span class="Constant"> 1</span>
<span id="L502" class="LineNr"> 502 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L503" class="LineNr"> 503 </span>  go-render? <span class="Special">&lt;-</span> copy<span class="Constant"> false</span>
<span id="L504" class="LineNr"> 504 </span>]
<span id="L505" class="LineNr"> 505 </span>
<span id="L506" class="LineNr"> 506 </span><span class="muScenario">scenario</span> editor-moves-cursor-to-next-line-with-right-arrow [
<span id="L507" class="LineNr"> 507 </span>  <span class="Constant">local-scope</span>
<span id="L508" class="LineNr"> 508 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L509" class="LineNr"> 509 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L510" class="LineNr"> 510 </span><span class="Constant">d]</span>
<span id="L511" class="LineNr"> 511 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L512" class="LineNr"> 512 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L513" class="LineNr"> 513 </span>  $clear-trace
<span id="L514" class="LineNr"> 514 </span>  <span class="Comment"># type right-arrow a few times to get to start of second line</span>
<span id="L515" class="LineNr"> 515 </span>  assume-console [
<span id="L516" class="LineNr"> 516 </span>    press right-arrow
<span id="L517" class="LineNr"> 517 </span>    press right-arrow
<span id="L518" class="LineNr"> 518 </span>    press right-arrow
<span id="L519" class="LineNr"> 519 </span>    press right-arrow  <span class="Comment"># next line</span>
<span id="L520" class="LineNr"> 520 </span>  ]
<span id="L521" class="LineNr"> 521 </span>  run [
<span id="L522" class="LineNr"> 522 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L523" class="LineNr"> 523 </span>  ]
<span id="L524" class="LineNr"> 524 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L525" class="LineNr"> 525 </span>  <span class="Comment"># type something and ensure it goes where it should</span>
<span id="L526" class="LineNr"> 526 </span>  assume-console [
<span id="L527" class="LineNr"> 527 </span>    type <span class="Constant">[0]</span>
<span id="L528" class="LineNr"> 528 </span>  ]
<span id="L529" class="LineNr"> 529 </span>  run [
<span id="L530" class="LineNr"> 530 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L531" class="LineNr"> 531 </span>  ]
<span id="L532" class="LineNr"> 532 </span>  screen-should-contain [
<span id="L533" class="LineNr"> 533 </span>   <span class="Constant"> .          .</span>
<span id="L534" class="LineNr"> 534 </span>   <span class="Constant"> .abc       .</span>
<span id="L535" class="LineNr"> 535 </span>   <span class="Constant"> .0d        .</span>
<span id="L536" class="LineNr"> 536 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L537" class="LineNr"> 537 </span>   <span class="Constant"> .          .</span>
<span id="L538" class="LineNr"> 538 </span>  ]
<span id="L539" class="LineNr"> 539 </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="L540" class="LineNr"> 540 </span>]
<span id="L541" class="LineNr"> 541 </span>
<span id="L542" class="LineNr"> 542 </span><span class="muScenario">scenario</span> editor-moves-cursor-to-next-line-with-right-arrow-2 [
<span id="L543" class="LineNr"> 543 </span>  <span class="Constant">local-scope</span>
<span id="L544" class="LineNr"> 544 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L545" class="LineNr"> 545 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L546" class="LineNr"> 546 </span><span class="Constant">d]</span>
<span id="L547" class="LineNr"> 547 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">1/left</span>, <span class="Constant">10/right</span>
<span id="L548" class="LineNr"> 548 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L549" class="LineNr"> 549 </span>  assume-console [
<span id="L550" class="LineNr"> 550 </span>    press right-arrow
<span id="L551" class="LineNr"> 551 </span>    press right-arrow
<span id="L552" class="LineNr"> 552 </span>    press right-arrow
<span id="L553" class="LineNr"> 553 </span>    press right-arrow  <span class="Comment"># next line</span>
<span id="L554" class="LineNr"> 554 </span>    type <span class="Constant">[0]</span>
<span id="L555" class="LineNr"> 555 </span>  ]
<span id="L556" class="LineNr"> 556 </span>  run [
<span id="L557" class="LineNr"> 557 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<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"> . abc      .</span>
<span id="L562" class="LineNr"> 562 </span>   <span class="Constant"> . 0d       .</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="L565" class="LineNr"> 565 </span>  ]
<span id="L566" class="LineNr"> 566 </span>]
<span id="L567" class="LineNr"> 567 </span>
<span id="L568" class="LineNr"> 568 </span><span class="muScenario">scenario</span> editor-moves-cursor-to-next-wrapped-line-with-right-arrow [
<span id="L569" class="LineNr"> 569 </span>  <span class="Constant">local-scope</span>
<span id="L570" class="LineNr"> 570 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L571" class="LineNr"> 571 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abcdef]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L572" class="LineNr"> 572 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L573" class="LineNr"> 573 </span>  $clear-trace
<span id="L574" class="LineNr"> 574 </span>  assume-console [
<span id="L575" class="LineNr"> 575 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
<span id="L576" class="LineNr"> 576 </span>    press right-arrow
<span id="L577" class="LineNr"> 577 </span>  ]
<span id="L578" class="LineNr"> 578 </span>  run [
<span id="L579" class="LineNr"> 579 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L580" class="LineNr"> 580 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L581" class="LineNr"> 581 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</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"> .abcd↩     .</span>
<span id="L586" class="LineNr"> 586 </span>   <span class="Constant"> .ef        .</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 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="L593" class="LineNr"> 593 </span>  ]
<span id="L594" class="LineNr"> 594 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L595" class="LineNr"> 595 </span>]
<span id="L596" class="LineNr"> 596 </span>
<span id="L597" class="LineNr"> 597 </span><span class="muScenario">scenario</span> editor-moves-cursor-to-next-wrapped-line-with-right-arrow-2 [
<span id="L598" class="LineNr"> 598 </span>  <span class="Constant">local-scope</span>
<span id="L599" class="LineNr"> 599 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L600" class="LineNr"> 600 </span>  <span class="Comment"># line just barely wrapping</span>
<span id="L601" class="LineNr"> 601 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abcde]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L602" class="LineNr"> 602 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L603" class="LineNr"> 603 </span>  $clear-trace
<span id="L604" class="LineNr"> 604 </span>  <span class="Comment"># position cursor at last character before wrap and hit right-arrow</span>
<span id="L605" class="LineNr"> 605 </span>  assume-console [
<span id="L606" class="LineNr"> 606 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
<span id="L607" class="LineNr"> 607 </span>    press right-arrow
<span id="L608" class="LineNr"> 608 </span>  ]
<span id="L609" class="LineNr"> 609 </span>  run [
<span id="L610" class="LineNr"> 610 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L611" class="LineNr"> 611 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L612" class="LineNr"> 612 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L613" class="LineNr"> 613 </span>  ]
<span id="L614" class="LineNr"> 614 </span>  memory-should-contain [
<span id="L615" class="LineNr"> 615 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L616" class="LineNr"> 616 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L617" class="LineNr"> 617 </span>  ]
<span id="L618" class="LineNr"> 618 </span>  <span class="Comment"># now hit right arrow again</span>
<span id="L619" class="LineNr"> 619 </span>  assume-console [
<span id="L620" class="LineNr"> 620 </span>    press right-arrow
<span id="L621" class="LineNr"> 621 </span>  ]
<span id="L622" class="LineNr"> 622 </span>  run [
<span id="L623" class="LineNr"> 623 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L624" class="LineNr"> 624 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L625" class="LineNr"> 625 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L626" class="LineNr"> 626 </span>  ]
<span id="L627" class="LineNr"> 627 </span>  memory-should-contain [
<span id="L628" class="LineNr"> 628 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L629" class="LineNr"> 629 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L630" class="LineNr"> 630 </span>  ]
<span id="L631" class="LineNr"> 631 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L632" class="LineNr"> 632 </span>]
<span id="L633" class="LineNr"> 633 </span>
<span id="L634" class="LineNr"> 634 </span><span class="muScenario">scenario</span> editor-moves-cursor-to-next-wrapped-line-with-right-arrow-3 [
<span id="L635" class="LineNr"> 635 </span>  <span class="Constant">local-scope</span>
<span id="L636" class="LineNr"> 636 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L637" class="LineNr"> 637 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abcdef]</span>, <span class="Constant">1/left</span>, <span class="Constant">6/right</span>
<span id="L638" class="LineNr"> 638 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L639" class="LineNr"> 639 </span>  $clear-trace
<span id="L640" class="LineNr"> 640 </span>  assume-console [
<span id="L641" class="LineNr"> 641 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 4</span>
<span id="L642" class="LineNr"> 642 </span>    press right-arrow
<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#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L646" class="LineNr"> 646 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L647" class="LineNr"> 647 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L648" class="LineNr"> 648 </span>  ]
<span id="L649" class="LineNr"> 649 </span>  screen-should-contain [
<span id="L650" class="LineNr"> 650 </span>   <span class="Constant"> .          .</span>
<span id="L651" class="LineNr"> 651 </span>   <span class="Constant"> . abcd↩    .</span>
<span id="L652" class="LineNr"> 652 </span>   <span class="Constant"> . ef       .</span>
<span id="L653" class="LineNr"> 653 </span>   <span class="Constant"> . ╌╌╌╌╌    .</span>
<span id="L654" class="LineNr"> 654 </span>   <span class="Constant"> .          .</span>
<span id="L655" class="LineNr"> 655 </span>  ]
<span id="L656" class="LineNr"> 656 </span>  memory-should-contain [
<span id="L657" class="LineNr"> 657 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L658" class="LineNr"> 658 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L659" class="LineNr"> 659 </span>  ]
<span id="L660" class="LineNr"> 660 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L661" class="LineNr"> 661 </span>]
<span id="L662" class="LineNr"> 662 </span>
<span id="L663" class="LineNr"> 663 </span><span class="muScenario">scenario</span> editor-moves-cursor-to-next-line-with-right-arrow-at-end-of-line [
<span id="L664" class="LineNr"> 664 </span>  <span class="Constant">local-scope</span>
<span id="L665" class="LineNr"> 665 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L666" class="LineNr"> 666 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L667" class="LineNr"> 667 </span><span class="Constant">d]</span>
<span id="L668" class="LineNr"> 668 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L669" class="LineNr"> 669 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L670" class="LineNr"> 670 </span>  $clear-trace
<span id="L671" class="LineNr"> 671 </span>  <span class="Comment"># move to end of line, press right-arrow, type a character</span>
<span id="L672" class="LineNr"> 672 </span>  assume-console [
<span id="L673" class="LineNr"> 673 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
<span id="L674" class="LineNr"> 674 </span>    press right-arrow
<span id="L675" class="LineNr"> 675 </span>    type <span class="Constant">[0]</span>
<span id="L676" class="LineNr"> 676 </span>  ]
<span id="L677" class="LineNr"> 677 </span>  run [
<span id="L678" class="LineNr"> 678 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L679" class="LineNr"> 679 </span>  ]
<span id="L680" class="LineNr"> 680 </span>  <span class="Comment"># new character should be in next line</span>
<span id="L681" class="LineNr"> 681 </span>  screen-should-contain [
<span id="L682" class="LineNr"> 682 </span>   <span class="Constant"> .          .</span>
<span id="L683" class="LineNr"> 683 </span>   <span class="Constant"> .abc       .</span>
<span id="L684" class="LineNr"> 684 </span>   <span class="Constant"> .0d        .</span>
<span id="L685" class="LineNr"> 685 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L686" class="LineNr"> 686 </span>   <span class="Constant"> .          .</span>
<span id="L687" class="LineNr"> 687 </span>  ]
<span id="L688" class="LineNr"> 688 </span>  check-trace-count-for-label<span class="Constant"> 2</span>, <span class="Constant">[print-character]</span>
<span id="L689" class="LineNr"> 689 </span>]
<span id="L690" class="LineNr"> 690 </span>
<span id="L691" class="LineNr"> 691 </span><span class="Comment"># todo: ctrl-right: next word-end</span>
<span id="L692" class="LineNr"> 692 </span>
<span id="L693" class="LineNr"> 693 </span><span class="Comment"># left arrow</span>
<span id="L694" class="LineNr"> 694 </span>
<span id="L695" class="LineNr"> 695 </span><span class="muScenario">scenario</span> editor-moves-cursor-left-with-key [
<span id="L696" class="LineNr"> 696 </span>  <span class="Constant">local-scope</span>
<span id="L697" class="LineNr"> 697 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L698" class="LineNr"> 698 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abc]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L699" class="LineNr"> 699 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L700" class="LineNr"> 700 </span>  $clear-trace
<span id="L701" class="LineNr"> 701 </span>  assume-console [
<span id="L702" class="LineNr"> 702 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 2</span>
<span id="L703" class="LineNr"> 703 </span>    press left-arrow
<span id="L704" class="LineNr"> 704 </span>    type <span class="Constant">[0]</span>
<span id="L705" class="LineNr"> 705 </span>  ]
<span id="L706" class="LineNr"> 706 </span>  run [
<span id="L707" class="LineNr"> 707 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L708" class="LineNr"> 708 </span>  ]
<span id="L709" class="LineNr"> 709 </span>  screen-should-contain [
<span id="L710" class="LineNr"> 710 </span>   <span class="Constant"> .          .</span>
<span id="L711" class="LineNr"> 711 </span>   <span class="Constant"> .a0bc      .</span>
<span id="L712" class="LineNr"> 712 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L713" class="LineNr"> 713 </span>   <span class="Constant"> .          .</span>
<span id="L714" class="LineNr"> 714 </span>  ]
<span id="L715" class="LineNr"> 715 </span>  check-trace-count-for-label<span class="Constant"> 3</span>, <span class="Constant">[print-character]</span>
<span id="L716" class="LineNr"> 716 </span>]
<span id="L717" class="LineNr"> 717 </span>
<span id="L718" class="LineNr"> 718 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L199'>&lt;handle-special-key&gt;</a></span> [
<span id="L719" class="LineNr"> 719 </span>  <span class="Delimiter">{</span>
<span id="L720" class="LineNr"> 720 </span>    move-to-previous-character?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65515/left-arrow</span>
<span id="L721" class="LineNr"> 721 </span>    <span class="muControl">break-unless</span> move-to-previous-character?
<span id="L722" class="LineNr"> 722 </span>    trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[left arrow]</span>
<span id="L723" class="LineNr"> 723 </span>    <span class="Comment"># if not at start of text (before-cursor at § sentinel)</span>
<span id="L724" class="LineNr"> 724 </span>    <a href='../065duplex_list.mu.html#L38'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L38'>prev</a> before-cursor
<span id="L725" class="LineNr"> 725 </span>    <span class="muControl">return-unless</span> <a href='../065duplex_list.mu.html#L38'>prev</a>,<span class="Constant"> false/don't-render</span>
<span id="L726" class="LineNr"> 726 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L727" class="LineNr"> 727 </span>    go-render? <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L156'>move-cursor-coordinates-left</a> editor
<span id="L728" class="LineNr"> 728 </span>    before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L38'>prev</a>
<span id="L729" class="LineNr"> 729 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L730" class="LineNr"> 730 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">1/left-arrow</span>
<span id="L731" class="LineNr"> 731 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L732" class="LineNr"> 732 </span>   <span class="muControl"> return</span>
<span id="L733" class="LineNr"> 733 </span>  <span class="Delimiter">}</span>
<span id="L734" class="LineNr"> 734 </span>]
<span id="L735" class="LineNr"> 735 </span>
<span id="L736" class="LineNr"> 736 </span><span class="muScenario">scenario</span> editor-moves-cursor-to-previous-line-with-left-arrow-at-start-of-line [
<span id="L737" class="LineNr"> 737 </span>  <span class="Constant">local-scope</span>
<span id="L738" class="LineNr"> 738 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L739" class="LineNr"> 739 </span>  <span class="Comment"># initialize editor with two lines</span>
<span id="L740" class="LineNr"> 740 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L741" class="LineNr"> 741 </span><span class="Constant">d]</span>
<span id="L742" class="LineNr"> 742 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L743" class="LineNr"> 743 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L744" class="LineNr"> 744 </span>  $clear-trace
<span id="L745" class="LineNr"> 745 </span>  <span class="Comment"># position cursor at start of second line (so there's no previous newline)</span>
<span id="L746" class="LineNr"> 746 </span>  assume-console [
<span id="L747" class="LineNr"> 747 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
<span id="L748" class="LineNr"> 748 </span>    press left-arrow
<span id="L749" class="LineNr"> 749 </span>  ]
<span id="L750" class="LineNr"> 750 </span>  run [
<span id="L751" class="LineNr"> 751 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L752" class="LineNr"> 752 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L753" class="LineNr"> 753 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L754" class="LineNr"> 754 </span>  ]
<span id="L755" class="LineNr"> 755 </span>  memory-should-contain [
<span id="L756" class="LineNr"> 756 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L757" class="LineNr"> 757 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L758" class="LineNr"> 758 </span>  ]
<span id="L759" class="LineNr"> 759 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L760" class="LineNr"> 760 </span>]
<span id="L761" class="LineNr"> 761 </span>
<span id="L762" class="LineNr"> 762 </span><span class="muScenario">scenario</span> editor-moves-cursor-to-previous-line-with-left-arrow-at-start-of-line-2 [
<span id="L763" class="LineNr"> 763 </span>  <span class="Constant">local-scope</span>
<span id="L764" class="LineNr"> 764 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L765" class="LineNr"> 765 </span>  <span class="Comment"># initialize editor with three lines</span>
<span id="L766" class="LineNr"> 766 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L767" class="LineNr"> 767 </span><span class="Constant">def</span>
<span id="L768" class="LineNr"> 768 </span><span class="Constant">g]</span>
<span id="L769" class="LineNr"> 769 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s:text, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L770" class="LineNr"> 770 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L771" class="LineNr"> 771 </span>  $clear-trace
<span id="L772" class="LineNr"> 772 </span>  <span class="Comment"># position cursor further down (so there's a newline before the character at</span>
<span id="L773" class="LineNr"> 773 </span>  <span class="Comment"># the cursor)</span>
<span id="L774" class="LineNr"> 774 </span>  assume-console [
<span id="L775" class="LineNr"> 775 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
<span id="L776" class="LineNr"> 776 </span>    press left-arrow
<span id="L777" class="LineNr"> 777 </span>    type <span class="Constant">[0]</span>
<span id="L778" class="LineNr"> 778 </span>  ]
<span id="L779" class="LineNr"> 779 </span>  run [
<span id="L780" class="LineNr"> 780 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L781" class="LineNr"> 781 </span>  ]
<span id="L782" class="LineNr"> 782 </span>  screen-should-contain [
<span id="L783" class="LineNr"> 783 </span>   <span class="Constant"> .          .</span>
<span id="L784" class="LineNr"> 784 </span>   <span class="Constant"> .abc       .</span>
<span id="L785" class="LineNr"> 785 </span>   <span class="Constant"> .def0      .</span>
<span id="L786" class="LineNr"> 786 </span>   <span class="Constant"> .g         .</span>
<span id="L787" class="LineNr"> 787 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L788" class="LineNr"> 788 </span>  ]
<span id="L789" class="LineNr"> 789 </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="L790" class="LineNr"> 790 </span>]
<span id="L791" class="LineNr"> 791 </span>
<span id="L792" class="LineNr"> 792 </span><span class="muScenario">scenario</span> editor-moves-cursor-to-previous-line-with-left-arrow-at-start-of-line-3 [
<span id="L793" class="LineNr"> 793 </span>  <span class="Constant">local-scope</span>
<span id="L794" class="LineNr"> 794 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L795" class="LineNr"> 795 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L796" class="LineNr"> 796 </span><span class="Constant">def</span>
<span id="L797" class="LineNr"> 797 </span><span class="Constant">g]</span>
<span id="L798" class="LineNr"> 798 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L799" class="LineNr"> 799 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L800" class="LineNr"> 800 </span>  $clear-trace
<span id="L801" class="LineNr"> 801 </span>  <span class="Comment"># position cursor at start of text, press left-arrow, then type a character</span>
<span id="L802" class="LineNr"> 802 </span>  assume-console [
<span id="L803" class="LineNr"> 803 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 0</span>
<span id="L804" class="LineNr"> 804 </span>    press left-arrow
<span id="L805" class="LineNr"> 805 </span>    type <span class="Constant">[0]</span>
<span id="L806" class="LineNr"> 806 </span>  ]
<span id="L807" class="LineNr"> 807 </span>  run [
<span id="L808" class="LineNr"> 808 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L809" class="LineNr"> 809 </span>  ]
<span id="L810" class="LineNr"> 810 </span>  <span class="Comment"># left-arrow should have had no effect</span>
<span id="L811" class="LineNr"> 811 </span>  screen-should-contain [
<span id="L812" class="LineNr"> 812 </span>   <span class="Constant"> .          .</span>
<span id="L813" class="LineNr"> 813 </span>   <span class="Constant"> .0abc      .</span>
<span id="L814" class="LineNr"> 814 </span>   <span class="Constant"> .def       .</span>
<span id="L815" class="LineNr"> 815 </span>   <span class="Constant"> .g         .</span>
<span id="L816" class="LineNr"> 816 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L817" class="LineNr"> 817 </span>  ]
<span id="L818" class="LineNr"> 818 </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="L819" class="LineNr"> 819 </span>]
<span id="L820" class="LineNr"> 820 </span>
<span id="L821" class="LineNr"> 821 </span><span class="muScenario">scenario</span> editor-moves-cursor-to-previous-line-with-left-arrow-at-start-of-line-4 [
<span id="L822" class="LineNr"> 822 </span>  <span class="Constant">local-scope</span>
<span id="L823" class="LineNr"> 823 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L824" class="LineNr"> 824 </span>  <span class="Comment"># initialize editor with text containing an empty line</span>
<span id="L825" class="LineNr"> 825 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L826" class="LineNr"> 826 </span>
<span id="L827" class="LineNr"> 827 </span>d]
<span id="L828" class="LineNr"> 828 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L829" class="LineNr"> 829 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e:&amp;:editor
<span id="L830" class="LineNr"> 830 </span>  $clear-trace
<span id="L831" class="LineNr"> 831 </span>  <span class="Comment"># position cursor right after empty line</span>
<span id="L832" class="LineNr"> 832 </span>  assume-console [
<span id="L833" class="LineNr"> 833 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
<span id="L834" class="LineNr"> 834 </span>    press left-arrow
<span id="L835" class="LineNr"> 835 </span>    type <span class="Constant">[0]</span>
<span id="L836" class="LineNr"> 836 </span>  ]
<span id="L837" class="LineNr"> 837 </span>  run [
<span id="L838" class="LineNr"> 838 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L839" class="LineNr"> 839 </span>  ]
<span id="L840" class="LineNr"> 840 </span>  screen-should-contain [
<span id="L841" class="LineNr"> 841 </span>   <span class="Constant"> .          .</span>
<span id="L842" class="LineNr"> 842 </span>   <span class="Constant"> .abc       .</span>
<span id="L843" class="LineNr"> 843 </span>   <span class="Constant"> .0         .</span>
<span id="L844" class="LineNr"> 844 </span>   <span class="Constant"> .d         .</span>
<span id="L845" class="LineNr"> 845 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L846" class="LineNr"> 846 </span>  ]
<span id="L847" class="LineNr"> 847 </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="L848" class="LineNr"> 848 </span>]
<span id="L849" class="LineNr"> 849 </span>
<span id="L850" class="LineNr"> 850 </span><span class="muScenario">scenario</span> editor-moves-across-screen-lines-across-wrap-with-left-arrow [
<span id="L851" class="LineNr"> 851 </span>  <span class="Constant">local-scope</span>
<span id="L852" class="LineNr"> 852 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L853" class="LineNr"> 853 </span>  <span class="Comment"># initialize editor with a wrapping line</span>
<span id="L854" class="LineNr"> 854 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abcdef]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L855" class="LineNr"> 855 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L856" class="LineNr"> 856 </span>  $clear-trace
<span id="L857" class="LineNr"> 857 </span>  screen-should-contain [
<span id="L858" class="LineNr"> 858 </span>   <span class="Constant"> .          .</span>
<span id="L859" class="LineNr"> 859 </span>   <span class="Constant"> .abcd↩     .</span>
<span id="L860" class="LineNr"> 860 </span>   <span class="Constant"> .ef        .</span>
<span id="L861" class="LineNr"> 861 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L862" class="LineNr"> 862 </span>   <span class="Constant"> .          .</span>
<span id="L863" class="LineNr"> 863 </span>  ]
<span id="L864" class="LineNr"> 864 </span>  <span class="Comment"># position cursor right after empty line</span>
<span id="L865" class="LineNr"> 865 </span>  assume-console [
<span id="L866" class="LineNr"> 866 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
<span id="L867" class="LineNr"> 867 </span>    press left-arrow
<span id="L868" class="LineNr"> 868 </span>  ]
<span id="L869" class="LineNr"> 869 </span>  run [
<span id="L870" class="LineNr"> 870 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L871" class="LineNr"> 871 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L872" class="LineNr"> 872 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L873" class="LineNr"> 873 </span>  ]
<span id="L874" class="LineNr"> 874 </span>  memory-should-contain [
<span id="L875" class="LineNr"> 875 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># previous row</span>
<span id="L876" class="LineNr"> 876 </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="L877" class="LineNr"> 877 </span>  ]
<span id="L878" class="LineNr"> 878 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L879" class="LineNr"> 879 </span>]
<span id="L880" class="LineNr"> 880 </span>
<span id="L881" class="LineNr"> 881 </span><span class="muScenario">scenario</span> editor-moves-across-screen-lines-to-wrapping-line-with-left-arrow [
<span id="L882" class="LineNr"> 882 </span>  <span class="Constant">local-scope</span>
<span id="L883" class="LineNr"> 883 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L884" class="LineNr"> 884 </span>  <span class="Comment"># initialize editor with a wrapping line followed by a second line</span>
<span id="L885" class="LineNr"> 885 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abcdef</span>
<span id="L886" class="LineNr"> 886 </span><span class="Constant">g]</span>
<span id="L887" class="LineNr"> 887 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L888" class="LineNr"> 888 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L889" class="LineNr"> 889 </span>  $clear-trace
<span id="L890" class="LineNr"> 890 </span>  screen-should-contain [
<span id="L891" class="LineNr"> 891 </span>   <span class="Constant"> .          .</span>
<span id="L892" class="LineNr"> 892 </span>   <span class="Constant"> .abcd↩     .</span>
<span id="L893" class="LineNr"> 893 </span>   <span class="Constant"> .ef        .</span>
<span id="L894" class="LineNr"> 894 </span>   <span class="Constant"> .g         .</span>
<span id="L895" class="LineNr"> 895 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L896" class="LineNr"> 896 </span>  ]
<span id="L897" class="LineNr"> 897 </span>  <span class="Comment"># position cursor right after empty line</span>
<span id="L898" class="LineNr"> 898 </span>  assume-console [
<span id="L899" class="LineNr"> 899 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
<span id="L900" class="LineNr"> 900 </span>    press left-arrow
<span id="L901" class="LineNr"> 901 </span>  ]
<span id="L902" class="LineNr"> 902 </span>  run [
<span id="L903" class="LineNr"> 903 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<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>  ]
<span id="L907" class="LineNr"> 907 </span>  memory-should-contain [
<span id="L908" class="LineNr"> 908 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>  <span class="Comment"># previous row</span>
<span id="L909" class="LineNr"> 909 </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="L910" class="LineNr"> 910 </span>  ]
<span id="L911" class="LineNr"> 911 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L912" class="LineNr"> 912 </span>]
<span id="L913" class="LineNr"> 913 </span>
<span id="L914" class="LineNr"> 914 </span><span class="muScenario">scenario</span> editor-moves-across-screen-lines-to-non-wrapping-line-with-left-arrow [
<span id="L915" class="LineNr"> 915 </span>  <span class="Constant">local-scope</span>
<span id="L916" class="LineNr"> 916 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L917" class="LineNr"> 917 </span>  <span class="Comment"># initialize editor with a line on the verge of wrapping, followed by a second line</span>
<span id="L918" class="LineNr"> 918 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abcd</span>
<span id="L919" class="LineNr"> 919 </span><span class="Constant">e]</span>
<span id="L920" class="LineNr"> 920 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L921" class="LineNr"> 921 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L922" class="LineNr"> 922 </span>  $clear-trace
<span id="L923" class="LineNr"> 923 </span>  screen-should-contain [
<span id="L924" class="LineNr"> 924 </span>   <span class="Constant"> .          .</span>
<span id="L925" class="LineNr"> 925 </span>   <span class="Constant"> .abcd      .</span>
<span id="L926" class="LineNr"> 926 </span>   <span class="Constant"> .e         .</span>
<span id="L927" class="LineNr"> 927 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L928" class="LineNr"> 928 </span>   <span class="Constant"> .          .</span>
<span id="L929" class="LineNr"> 929 </span>  ]
<span id="L930" class="LineNr"> 930 </span>  <span class="Comment"># position cursor right after empty line</span>
<span id="L931" class="LineNr"> 931 </span>  assume-console [
<span id="L932" class="LineNr"> 932 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
<span id="L933" class="LineNr"> 933 </span>    press left-arrow
<span id="L934" class="LineNr"> 934 </span>  ]
<span id="L935" class="LineNr"> 935 </span>  run [
<span id="L936" class="LineNr"> 936 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L937" class="LineNr"> 937 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L938" class="LineNr"> 938 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L939" class="LineNr"> 939 </span>  ]
<span id="L940" class="LineNr"> 940 </span>  memory-should-contain [
<span id="L941" class="LineNr"> 941 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># previous row</span>
<span id="L942" class="LineNr"> 942 </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="L943" class="LineNr"> 943 </span>  ]
<span id="L944" class="LineNr"> 944 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L945" class="LineNr"> 945 </span>]
<span id="L946" class="LineNr"> 946 </span>
<span id="L947" class="LineNr"> 947 </span><span class="Comment"># todo: ctrl-left: previous word-start</span>
<span id="L948" class="LineNr"> 948 </span>
<span id="L949" class="LineNr"> 949 </span><span class="Comment"># up arrow</span>
<span id="L950" class="LineNr"> 950 </span>
<span id="L951" class="LineNr"> 951 </span><span class="muScenario">scenario</span> editor-moves-to-previous-line-with-up-arrow [
<span id="L952" class="LineNr"> 952 </span>  <span class="Constant">local-scope</span>
<span id="L953" class="LineNr"> 953 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L954" class="LineNr"> 954 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L955" class="LineNr"> 955 </span><span class="Constant">def]</span>
<span id="L956" class="LineNr"> 956 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L957" class="LineNr"> 957 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L958" class="LineNr"> 958 </span>  $clear-trace
<span id="L959" class="LineNr"> 959 </span>  assume-console [
<span id="L960" class="LineNr"> 960 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
<span id="L961" class="LineNr"> 961 </span>    press up-arrow
<span id="L962" class="LineNr"> 962 </span>  ]
<span id="L963" class="LineNr"> 963 </span>  run [
<span id="L964" class="LineNr"> 964 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L965" class="LineNr"> 965 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L966" class="LineNr"> 966 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L967" class="LineNr"> 967 </span>  ]
<span id="L968" class="LineNr"> 968 </span>  memory-should-contain [
<span id="L969" class="LineNr"> 969 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L970" class="LineNr"> 970 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L971" class="LineNr"> 971 </span>  ]
<span id="L972" class="LineNr"> 972 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L973" class="LineNr"> 973 </span>  assume-console [
<span id="L974" class="LineNr"> 974 </span>    type <span class="Constant">[0]</span>
<span id="L975" class="LineNr"> 975 </span>  ]
<span id="L976" class="LineNr"> 976 </span>  run [
<span id="L977" class="LineNr"> 977 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L978" class="LineNr"> 978 </span>  ]
<span id="L979" class="LineNr"> 979 </span>  screen-should-contain [
<span id="L980" class="LineNr"> 980 </span>   <span class="Constant"> .          .</span>
<span id="L981" class="LineNr"> 981 </span>   <span class="Constant"> .a0bc      .</span>
<span id="L982" class="LineNr"> 982 </span>   <span class="Constant"> .def       .</span>
<span id="L983" class="LineNr"> 983 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L984" class="LineNr"> 984 </span>   <span class="Constant"> .          .</span>
<span id="L985" class="LineNr"> 985 </span>  ]
<span id="L986" class="LineNr"> 986 </span>]
<span id="L987" class="LineNr"> 987 </span>
<span id="L988" class="LineNr"> 988 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L199'>&lt;handle-special-key&gt;</a></span> [
<span id="L989" class="LineNr"> 989 </span>  <span class="Delimiter">{</span>
<span id="L990" class="LineNr"> 990 </span>    move-to-previous-line?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65517/up-arrow</span>
<span id="L991" class="LineNr"> 991 </span>    <span class="muControl">break-unless</span> move-to-previous-line?
<span id="L992" class="LineNr"> 992 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L993" class="LineNr"> 993 </span>    go-render? <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1000'>move-to-previous-line</a> editor
<span id="L994" class="LineNr"> 994 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">3/up-arrow</span>
<span id="L995" class="LineNr"> 995 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L996" class="LineNr"> 996 </span>   <span class="muControl"> return</span>
<span id="L997" class="LineNr"> 997 </span>  <span class="Delimiter">}</span>
<span id="L998" class="LineNr"> 998 </span>]
<span id="L999" class="LineNr"> 999 </span>
<span id="L1000" class="LineNr">1000 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L1000'>move-to-previous-line</a> editor:&amp;:editor<span class="muRecipe"> -&gt; </span>go-render?:bool, editor:&amp;:editor [
<span id="L1001" class="LineNr">1001 </span>  <span class="Constant">local-scope</span>
<span id="L1002" class="LineNr">1002 </span>  <span class="Constant">load-inputs</span>
<span id="L1003" class="LineNr">1003 </span>  go-render?:bool <span class="Special">&lt;-</span> copy<span class="Constant"> false</span>
<span id="L1004" class="LineNr">1004 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L1005" class="LineNr">1005 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L1006" class="LineNr">1006 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L1007" class="LineNr">1007 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L1008" class="LineNr">1008 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L1009" class="LineNr">1009 </span>  already-at-top?:bool <span class="Special">&lt;-</span> lesser-or-equal cursor-row, <span class="Constant">1/top</span>
<span id="L1010" class="LineNr">1010 </span>  <span class="Delimiter">{</span>
<span id="L1011" class="LineNr">1011 </span>    <span class="Comment"># if cursor not at top, move it</span>
<span id="L1012" class="LineNr">1012 </span>    <span class="muControl">break-if</span> already-at-top?
<span id="L1013" class="LineNr">1013 </span>    <span class="Comment"># if not at start of screen line, move to start of screen line (previous newline)</span>
<span id="L1014" class="LineNr">1014 </span>    <span class="Comment"># then scan back another line</span>
<span id="L1015" class="LineNr">1015 </span>    <span class="Comment"># if either step fails, give up without modifying cursor or coordinates</span>
<span id="L1016" class="LineNr">1016 </span>    curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy before-cursor
<span id="L1017" class="LineNr">1017 </span>    old:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy curr
<span id="L1018" class="LineNr">1018 </span>    <span class="Delimiter">{</span>
<span id="L1019" class="LineNr">1019 </span>      at-left?:bool <span class="Special">&lt;-</span> equal cursor-column, left
<span id="L1020" class="LineNr">1020 </span>      <span class="muControl">break-if</span> at-left?
<span id="L1021" class="LineNr">1021 </span>      curr <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1067'>before-previous-screen-line</a> curr, editor
<span id="L1022" class="LineNr">1022 </span>      no-motion?:bool <span class="Special">&lt;-</span> equal curr, old
<span id="L1023" class="LineNr">1023 </span>      <span class="muControl">return-if</span> no-motion?
<span id="L1024" class="LineNr">1024 </span>    <span class="Delimiter">}</span>
<span id="L1025" class="LineNr">1025 </span>    <span class="Delimiter">{</span>
<span id="L1026" class="LineNr">1026 </span>      curr <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1067'>before-previous-screen-line</a> curr, editor
<span id="L1027" class="LineNr">1027 </span>      no-motion?:bool <span class="Special">&lt;-</span> equal curr, old
<span id="L1028" class="LineNr">1028 </span>      <span class="muControl">return-if</span> no-motion?
<span id="L1029" class="LineNr">1029 </span>    <span class="Delimiter">}</span>
<span id="L1030" class="LineNr">1030 </span>    before-cursor <span class="Special">&lt;-</span> copy curr
<span id="L1031" class="LineNr">1031 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L1032" class="LineNr">1032 </span>    cursor-row <span class="Special">&lt;-</span> subtract cursor-row,<span class="Constant"> 1</span>
<span id="L1033" class="LineNr">1033 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
<span id="L1034" class="LineNr">1034 </span>    <span class="Comment"># scan ahead to right column or until end of line</span>
<span id="L1035" class="LineNr">1035 </span>    target-column:num <span class="Special">&lt;-</span> copy cursor-column
<span id="L1036" class="LineNr">1036 </span>    cursor-column <span class="Special">&lt;-</span> copy left
<span id="L1037" class="LineNr">1037 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L1038" class="LineNr">1038 </span>    <span class="Delimiter">{</span>
<span id="L1039" class="LineNr">1039 </span>      done?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-column, target-column
<span id="L1040" class="LineNr">1040 </span>      <span class="muControl">break-if</span> done?
<span id="L1041" class="LineNr">1041 </span>      curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-cursor
<span id="L1042" class="LineNr">1042 </span>      <span class="muControl">break-unless</span> curr
<span id="L1043" class="LineNr">1043 </span>      currc:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
<span id="L1044" class="LineNr">1044 </span>      at-newline?:bool <span class="Special">&lt;-</span> equal currc, <span class="Constant">10/newline</span>
<span id="L1045" class="LineNr">1045 </span>      <span class="muControl">break-if</span> at-newline?
<span id="L1046" class="LineNr">1046 </span>      <span class="Comment">#</span>
<span id="L1047" class="LineNr">1047 </span>      before-cursor <span class="Special">&lt;-</span> copy curr
<span id="L1048" class="LineNr">1048 </span>      *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L1049" class="LineNr">1049 </span>      cursor-column <span class="Special">&lt;-</span> add cursor-column,<span class="Constant"> 1</span>
<span id="L1050" class="LineNr">1050 </span>      *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L1051" class="LineNr">1051 </span>     <span class="muControl"> loop</span>
<span id="L1052" class="LineNr">1052 </span>    <span class="Delimiter">}</span>
<span id="L1053" class="LineNr">1053 </span>   <span class="muControl"> return</span>
<span id="L1054" class="LineNr">1054 </span>  <span class="Delimiter">}</span>
<span id="L1055" class="LineNr">1055 </span>  <span class="Delimiter">{</span>
<span id="L1056" class="LineNr">1056 </span>    <span class="Comment"># if cursor already at top, scroll up</span>
<span id="L1057" class="LineNr">1057 </span>    <span class="muControl">break-unless</span> already-at-top?
<span id="L1058" class="LineNr">1058 </span><span class="Constant">    &lt;scroll-up&gt;</span>
<span id="L1059" class="LineNr">1059 </span>   <span class="muControl"> return</span><span class="Constant"> true/go-render</span>
<span id="L1060" class="LineNr">1060 </span>  <span class="Delimiter">}</span>
<span id="L1061" class="LineNr">1061 </span>]
<span id="L1062" class="LineNr">1062 </span>
<span id="L1063" class="LineNr">1063 </span><span class="Comment"># Takes a pointer into the doubly-linked list, scans back to before start of</span>
<span id="L1064" class="LineNr">1064 </span><span class="Comment"># previous *wrapped* line.</span>
<span id="L1065" class="LineNr">1065 </span><span class="Comment"># Returns original if no next newline.</span>
<span id="L1066" class="LineNr">1066 </span><span class="Comment"># Beware: never return null pointer.</span>
<span id="L1067" class="LineNr">1067 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L1067'>before-previous-screen-line</a> in:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char, editor:&amp;:editor<span class="muRecipe"> -&gt; </span>out:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char [
<span id="L1068" class="LineNr">1068 </span>  <span class="Constant">local-scope</span>
<span id="L1069" class="LineNr">1069 </span>  <span class="Constant">load-inputs</span>
<span id="L1070" class="LineNr">1070 </span>  curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy in
<span id="L1071" class="LineNr">1071 </span>  c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
<span id="L1072" class="LineNr">1072 </span>  <span class="Comment"># compute max, number of characters to skip</span>
<span id="L1073" class="LineNr">1073 </span>  <span class="Comment">#   1 + len%(width-1)</span>
<span id="L1074" class="LineNr">1074 </span>  <span class="Comment">#   except rotate second term to vary from 1 to width-1 rather than 0 to width-2</span>
<span id="L1075" class="LineNr">1075 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L1076" class="LineNr">1076 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L1077" class="LineNr">1077 </span>  max-line-length:num <span class="Special">&lt;-</span> subtract right, left, <span class="Constant">-1/exclusive-right</span>, <span class="Constant">1/wrap-icon</span>
<span id="L1078" class="LineNr">1078 </span>  sentinel:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
<span id="L1079" class="LineNr">1079 </span>  len:num <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L219'>previous-line-length</a> curr, sentinel
<span id="L1080" class="LineNr">1080 </span>  <span class="Delimiter">{</span>
<span id="L1081" class="LineNr">1081 </span>    <span class="muControl">break-if</span> len
<span id="L1082" class="LineNr">1082 </span>    <span class="Comment"># empty line; just skip this newline</span>
<span id="L1083" class="LineNr">1083 </span>    <a href='../065duplex_list.mu.html#L38'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L38'>prev</a> curr
<span id="L1084" class="LineNr">1084 </span>    <span class="muControl">return-unless</span> <a href='../065duplex_list.mu.html#L38'>prev</a>, curr
<span id="L1085" class="LineNr">1085 </span>   <span class="muControl"> return</span> <a href='../065duplex_list.mu.html#L38'>prev</a>
<span id="L1086" class="LineNr">1086 </span>  <span class="Delimiter">}</span>
<span id="L1087" class="LineNr">1087 </span>  _, max:num <span class="Special">&lt;-</span> divide-with-remainder len, max-line-length
<span id="L1088" class="LineNr">1088 </span>  <span class="Comment"># remainder 0 =&gt; scan one width-worth</span>
<span id="L1089" class="LineNr">1089 </span>  <span class="Delimiter">{</span>
<span id="L1090" class="LineNr">1090 </span>    <span class="muControl">break-if</span> max
<span id="L1091" class="LineNr">1091 </span>    max <span class="Special">&lt;-</span> copy max-line-length
<span id="L1092" class="LineNr">1092 </span>  <span class="Delimiter">}</span>
<span id="L1093" class="LineNr">1093 </span>  max <span class="Special">&lt;-</span> add max,<span class="Constant"> 1</span>
<span id="L1094" class="LineNr">1094 </span>  count:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
<span id="L1095" class="LineNr">1095 </span>  <span class="Comment"># skip 'max' characters</span>
<span id="L1096" class="LineNr">1096 </span>  <span class="Delimiter">{</span>
<span id="L1097" class="LineNr">1097 </span>    done?:bool <span class="Special">&lt;-</span> greater-or-equal count, max
<span id="L1098" class="LineNr">1098 </span>    <span class="muControl">break-if</span> done?
<span id="L1099" class="LineNr">1099 </span>    <a href='../065duplex_list.mu.html#L38'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L38'>prev</a> curr
<span id="L1100" class="LineNr">1100 </span>    <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L38'>prev</a>
<span id="L1101" class="LineNr">1101 </span>    curr <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L38'>prev</a>
<span id="L1102" class="LineNr">1102 </span>    count <span class="Special">&lt;-</span> add count,<span class="Constant"> 1</span>
<span id="L1103" class="LineNr">1103 </span>   <span class="muControl"> loop</span>
<span id="L1104" class="LineNr">1104 </span>  <span class="Delimiter">}</span>
<span id="L1105" class="LineNr">1105 </span> <span class="muControl"> return</span> curr
<span id="L1106" class="LineNr">1106 </span>]
<span id="L1107" class="LineNr">1107 </span>
<span id="L1108" class="LineNr">1108 </span><span class="muScenario">scenario</span> editor-adjusts-column-at-previous-line [
<span id="L1109" class="LineNr">1109 </span>  <span class="Constant">local-scope</span>
<span id="L1110" class="LineNr">1110 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1111" class="LineNr">1111 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[ab</span>
<span id="L1112" class="LineNr">1112 </span><span class="Constant">def]</span>
<span id="L1113" class="LineNr">1113 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1114" class="LineNr">1114 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1115" class="LineNr">1115 </span>  $clear-trace
<span id="L1116" class="LineNr">1116 </span>  assume-console [
<span id="L1117" class="LineNr">1117 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
<span id="L1118" class="LineNr">1118 </span>    press up-arrow
<span id="L1119" class="LineNr">1119 </span>  ]
<span id="L1120" class="LineNr">1120 </span>  run [
<span id="L1121" class="LineNr">1121 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1122" class="LineNr">1122 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1123" class="LineNr">1123 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1124" class="LineNr">1124 </span>  ]
<span id="L1125" class="LineNr">1125 </span>  memory-should-contain [
<span id="L1126" class="LineNr">1126 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1127" class="LineNr">1127 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1128" class="LineNr">1128 </span>  ]
<span id="L1129" class="LineNr">1129 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1130" class="LineNr">1130 </span>  assume-console [
<span id="L1131" class="LineNr">1131 </span>    type <span class="Constant">[0]</span>
<span id="L1132" class="LineNr">1132 </span>  ]
<span id="L1133" class="LineNr">1133 </span>  run [
<span id="L1134" class="LineNr">1134 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1135" class="LineNr">1135 </span>  ]
<span id="L1136" class="LineNr">1136 </span>  screen-should-contain [
<span id="L1137" class="LineNr">1137 </span>   <span class="Constant"> .          .</span>
<span id="L1138" class="LineNr">1138 </span>   <span class="Constant"> .ab0       .</span>
<span id="L1139" class="LineNr">1139 </span>   <span class="Constant"> .def       .</span>
<span id="L1140" class="LineNr">1140 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1141" class="LineNr">1141 </span>   <span class="Constant"> .          .</span>
<span id="L1142" class="LineNr">1142 </span>  ]
<span id="L1143" class="LineNr">1143 </span>]
<span id="L1144" class="LineNr">1144 </span>
<span id="L1145" class="LineNr">1145 </span><span class="muScenario">scenario</span> editor-adjusts-column-at-empty-line [
<span id="L1146" class="LineNr">1146 </span>  <span class="Constant">local-scope</span>
<span id="L1147" class="LineNr">1147 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1148" class="LineNr">1148 </span>  s:text <span class="Special">&lt;-</span> new [
<span id="L1149" class="LineNr">1149 </span><span class="muRecipe">def</span>]
<span id="L1150" class="LineNr">1150 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1151" class="LineNr">1151 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1152" class="LineNr">1152 </span>  $clear-trace
<span id="L1153" class="LineNr">1153 </span>  assume-console [
<span id="L1154" class="LineNr">1154 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
<span id="L1155" class="LineNr">1155 </span>    press up-arrow
<span id="L1156" class="LineNr">1156 </span>  ]
<span id="L1157" class="LineNr">1157 </span>  run [
<span id="L1158" class="LineNr">1158 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1159" class="LineNr">1159 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1160" class="LineNr">1160 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1161" class="LineNr">1161 </span>  ]
<span id="L1162" class="LineNr">1162 </span>  memory-should-contain [
<span id="L1163" class="LineNr">1163 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1164" class="LineNr">1164 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L1165" class="LineNr">1165 </span>  ]
<span id="L1166" class="LineNr">1166 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1167" class="LineNr">1167 </span>  assume-console [
<span id="L1168" class="LineNr">1168 </span>    type <span class="Constant">[0]</span>
<span id="L1169" class="LineNr">1169 </span>  ]
<span id="L1170" class="LineNr">1170 </span>  run [
<span id="L1171" class="LineNr">1171 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1172" class="LineNr">1172 </span>  ]
<span id="L1173" class="LineNr">1173 </span>  screen-should-contain [
<span id="L1174" class="LineNr">1174 </span>   <span class="Constant"> .          .</span>
<span id="L1175" class="LineNr">1175 </span>   <span class="Constant"> .0         .</span>
<span id="L1176" class="LineNr">1176 </span>   <span class="Constant"> .def       .</span>
<span id="L1177" class="LineNr">1177 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1178" class="LineNr">1178 </span>   <span class="Constant"> .          .</span>
<span id="L1179" class="LineNr">1179 </span>  ]
<span id="L1180" class="LineNr">1180 </span>]
<span id="L1181" class="LineNr">1181 </span>
<span id="L1182" class="LineNr">1182 </span><span class="muScenario">scenario</span> editor-moves-to-previous-line-from-zero-margin [
<span id="L1183" class="LineNr">1183 </span>  <span class="Constant">local-scope</span>
<span id="L1184" class="LineNr">1184 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1185" class="LineNr">1185 </span>  <span class="Comment"># start out with three lines</span>
<span id="L1186" class="LineNr">1186 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L1187" class="LineNr">1187 </span><span class="Constant">def</span>
<span id="L1188" class="LineNr">1188 </span><span class="Constant">ghi]</span>
<span id="L1189" class="LineNr">1189 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1190" class="LineNr">1190 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1191" class="LineNr">1191 </span>  $clear-trace
<span id="L1192" class="LineNr">1192 </span>  <span class="Comment"># click on the third line and hit up-arrow, so you end up just after a newline</span>
<span id="L1193" class="LineNr">1193 </span>  assume-console [
<span id="L1194" class="LineNr">1194 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
<span id="L1195" class="LineNr">1195 </span>    press up-arrow
<span id="L1196" class="LineNr">1196 </span>  ]
<span id="L1197" class="LineNr">1197 </span>  run [
<span id="L1198" class="LineNr">1198 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1199" class="LineNr">1199 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1200" class="LineNr">1200 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1201" class="LineNr">1201 </span>  ]
<span id="L1202" class="LineNr">1202 </span>  memory-should-contain [
<span id="L1203" class="LineNr">1203 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1204" class="LineNr">1204 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L1205" class="LineNr">1205 </span>  ]
<span id="L1206" class="LineNr">1206 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1207" class="LineNr">1207 </span>  assume-console [
<span id="L1208" class="LineNr">1208 </span>    type <span class="Constant">[0]</span>
<span id="L1209" class="LineNr">1209 </span>  ]
<span id="L1210" class="LineNr">1210 </span>  run [
<span id="L1211" class="LineNr">1211 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1212" class="LineNr">1212 </span>  ]
<span id="L1213" class="LineNr">1213 </span>  screen-should-contain [
<span id="L1214" class="LineNr">1214 </span>   <span class="Constant"> .          .</span>
<span id="L1215" class="LineNr">1215 </span>   <span class="Constant"> .abc       .</span>
<span id="L1216" class="LineNr">1216 </span>   <span class="Constant"> .0def      .</span>
<span id="L1217" class="LineNr">1217 </span>   <span class="Constant"> .ghi       .</span>
<span id="L1218" class="LineNr">1218 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1219" class="LineNr">1219 </span>  ]
<span id="L1220" class="LineNr">1220 </span>]
<span id="L1221" class="LineNr">1221 </span>
<span id="L1222" class="LineNr">1222 </span><span class="muScenario">scenario</span> editor-moves-to-previous-line-from-left-margin [
<span id="L1223" class="LineNr">1223 </span>  <span class="Constant">local-scope</span>
<span id="L1224" class="LineNr">1224 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1225" class="LineNr">1225 </span>  <span class="Comment"># start out with three lines</span>
<span id="L1226" class="LineNr">1226 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L1227" class="LineNr">1227 </span><span class="Constant">def</span>
<span id="L1228" class="LineNr">1228 </span><span class="Constant">ghi]</span>
<span id="L1229" class="LineNr">1229 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">1/left</span>, <span class="Constant">10/right</span>
<span id="L1230" class="LineNr">1230 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1231" class="LineNr">1231 </span>  $clear-trace
<span id="L1232" class="LineNr">1232 </span>  <span class="Comment"># click on the third line and hit up-arrow, so you end up just after a newline</span>
<span id="L1233" class="LineNr">1233 </span>  assume-console [
<span id="L1234" class="LineNr">1234 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 1</span>
<span id="L1235" class="LineNr">1235 </span>    press up-arrow
<span id="L1236" class="LineNr">1236 </span>  ]
<span id="L1237" class="LineNr">1237 </span>  run [
<span id="L1238" class="LineNr">1238 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1239" class="LineNr">1239 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1240" class="LineNr">1240 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1241" class="LineNr">1241 </span>  ]
<span id="L1242" class="LineNr">1242 </span>  memory-should-contain [
<span id="L1243" class="LineNr">1243 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1244" class="LineNr">1244 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1245" class="LineNr">1245 </span>  ]
<span id="L1246" class="LineNr">1246 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1247" class="LineNr">1247 </span>  assume-console [
<span id="L1248" class="LineNr">1248 </span>    type <span class="Constant">[0]</span>
<span id="L1249" class="LineNr">1249 </span>  ]
<span id="L1250" class="LineNr">1250 </span>  run [
<span id="L1251" class="LineNr">1251 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1252" class="LineNr">1252 </span>  ]
<span id="L1253" class="LineNr">1253 </span>  screen-should-contain [
<span id="L1254" class="LineNr">1254 </span>   <span class="Constant"> .          .</span>
<span id="L1255" class="LineNr">1255 </span>   <span class="Constant"> . abc      .</span>
<span id="L1256" class="LineNr">1256 </span>   <span class="Constant"> . 0def     .</span>
<span id="L1257" class="LineNr">1257 </span>   <span class="Constant"> . ghi      .</span>
<span id="L1258" class="LineNr">1258 </span>   <span class="Constant"> . ╌╌╌╌╌╌╌╌╌.</span>
<span id="L1259" class="LineNr">1259 </span>  ]
<span id="L1260" class="LineNr">1260 </span>]
<span id="L1261" class="LineNr">1261 </span>
<span id="L1262" class="LineNr">1262 </span><span class="muScenario">scenario</span> editor-moves-to-top-line-in-presence-of-wrapped-line [
<span id="L1263" class="LineNr">1263 </span>  <span class="Constant">local-scope</span>
<span id="L1264" class="LineNr">1264 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1265" class="LineNr">1265 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abcde]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L1266" class="LineNr">1266 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1267" class="LineNr">1267 </span>  screen-should-contain [
<span id="L1268" class="LineNr">1268 </span>   <span class="Constant"> .          .</span>
<span id="L1269" class="LineNr">1269 </span>   <span class="Constant"> .abcd↩     .</span>
<span id="L1270" class="LineNr">1270 </span>   <span class="Constant"> .e         .</span>
<span id="L1271" class="LineNr">1271 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L1272" class="LineNr">1272 </span>  ]
<span id="L1273" class="LineNr">1273 </span>  $clear-trace
<span id="L1274" class="LineNr">1274 </span>  assume-console [
<span id="L1275" class="LineNr">1275 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
<span id="L1276" class="LineNr">1276 </span>    press up-arrow
<span id="L1277" class="LineNr">1277 </span>  ]
<span id="L1278" class="LineNr">1278 </span>  run [
<span id="L1279" class="LineNr">1279 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1280" class="LineNr">1280 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1281" class="LineNr">1281 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1282" class="LineNr">1282 </span>  ]
<span id="L1283" class="LineNr">1283 </span>  memory-should-contain [
<span id="L1284" class="LineNr">1284 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1285" class="LineNr">1285 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L1286" class="LineNr">1286 </span>  ]
<span id="L1287" class="LineNr">1287 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1288" class="LineNr">1288 </span>  assume-console [
<span id="L1289" class="LineNr">1289 </span>    type <span class="Constant">[0]</span>
<span id="L1290" class="LineNr">1290 </span>  ]
<span id="L1291" class="LineNr">1291 </span>  run [
<span id="L1292" class="LineNr">1292 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1293" class="LineNr">1293 </span>  ]
<span id="L1294" class="LineNr">1294 </span>  screen-should-contain [
<span id="L1295" class="LineNr">1295 </span>   <span class="Constant"> .          .</span>
<span id="L1296" class="LineNr">1296 </span>   <span class="Constant"> .0abc↩     .</span>
<span id="L1297" class="LineNr">1297 </span>   <span class="Constant"> .de        .</span>
<span id="L1298" class="LineNr">1298 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L1299" class="LineNr">1299 </span>  ]
<span id="L1300" class="LineNr">1300 </span>]
<span id="L1301" class="LineNr">1301 </span>
<span id="L1302" class="LineNr">1302 </span><span class="muScenario">scenario</span> editor-moves-to-top-line-in-presence-of-wrapped-line-2 [
<span id="L1303" class="LineNr">1303 </span>  <span class="Constant">local-scope</span>
<span id="L1304" class="LineNr">1304 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1305" class="LineNr">1305 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L1306" class="LineNr">1306 </span><span class="Constant">defgh]</span>
<span id="L1307" class="LineNr">1307 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L1308" class="LineNr">1308 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1309" class="LineNr">1309 </span>  screen-should-contain [
<span id="L1310" class="LineNr">1310 </span>   <span class="Constant"> .          .</span>
<span id="L1311" class="LineNr">1311 </span>   <span class="Constant"> .abc       .</span>
<span id="L1312" class="LineNr">1312 </span>   <span class="Constant"> .defg↩     .</span>
<span id="L1313" class="LineNr">1313 </span>   <span class="Constant"> .h         .</span>
<span id="L1314" class="LineNr">1314 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L1315" class="LineNr">1315 </span>  ]
<span id="L1316" class="LineNr">1316 </span>  $clear-trace
<span id="L1317" class="LineNr">1317 </span>  assume-console [
<span id="L1318" class="LineNr">1318 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
<span id="L1319" class="LineNr">1319 </span>    press up-arrow
<span id="L1320" class="LineNr">1320 </span>    press up-arrow
<span id="L1321" class="LineNr">1321 </span>  ]
<span id="L1322" class="LineNr">1322 </span>  run [
<span id="L1323" class="LineNr">1323 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1324" class="LineNr">1324 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1325" class="LineNr">1325 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1326" class="LineNr">1326 </span>  ]
<span id="L1327" class="LineNr">1327 </span>  memory-should-contain [
<span id="L1328" class="LineNr">1328 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1329" class="LineNr">1329 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L1330" class="LineNr">1330 </span>  ]
<span id="L1331" class="LineNr">1331 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1332" class="LineNr">1332 </span>  assume-console [
<span id="L1333" class="LineNr">1333 </span>    type <span class="Constant">[0]</span>
<span id="L1334" class="LineNr">1334 </span>  ]
<span id="L1335" class="LineNr">1335 </span>  run [
<span id="L1336" class="LineNr">1336 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1337" class="LineNr">1337 </span>  ]
<span id="L1338" class="LineNr">1338 </span>  screen-should-contain [
<span id="L1339" class="LineNr">1339 </span>   <span class="Constant"> .          .</span>
<span id="L1340" class="LineNr">1340 </span>   <span class="Constant"> .0abc      .</span>
<span id="L1341" class="LineNr">1341 </span>   <span class="Constant"> .defg↩     .</span>
<span id="L1342" class="LineNr">1342 </span>   <span class="Constant"> .h         .</span>
<span id="L1343" class="LineNr">1343 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L1344" class="LineNr">1344 </span>  ]
<span id="L1345" class="LineNr">1345 </span>]
<span id="L1346" class="LineNr">1346 </span>
<span id="L1347" class="LineNr">1347 </span><span class="Comment"># down arrow</span>
<span id="L1348" class="LineNr">1348 </span>
<span id="L1349" class="LineNr">1349 </span><span class="muScenario">scenario</span> editor-moves-to-next-line-with-down-arrow [
<span id="L1350" class="LineNr">1350 </span>  <span class="Constant">local-scope</span>
<span id="L1351" class="LineNr">1351 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1352" class="LineNr">1352 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L1353" class="LineNr">1353 </span><span class="Constant">def]</span>
<span id="L1354" class="LineNr">1354 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1355" class="LineNr">1355 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1356" class="LineNr">1356 </span>  $clear-trace
<span id="L1357" class="LineNr">1357 </span>  <span class="Comment"># cursor starts out at (1, 0)</span>
<span id="L1358" class="LineNr">1358 </span>  assume-console [
<span id="L1359" class="LineNr">1359 </span>    press down-arrow
<span id="L1360" class="LineNr">1360 </span>  ]
<span id="L1361" class="LineNr">1361 </span>  run [
<span id="L1362" class="LineNr">1362 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1363" class="LineNr">1363 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1364" class="LineNr">1364 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1365" class="LineNr">1365 </span>  ]
<span id="L1366" class="LineNr">1366 </span>  <span class="Comment"># ..and ends at (2, 0)</span>
<span id="L1367" class="LineNr">1367 </span>  memory-should-contain [
<span id="L1368" class="LineNr">1368 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1369" class="LineNr">1369 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L1370" class="LineNr">1370 </span>  ]
<span id="L1371" class="LineNr">1371 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1372" class="LineNr">1372 </span>  assume-console [
<span id="L1373" class="LineNr">1373 </span>    type <span class="Constant">[0]</span>
<span id="L1374" class="LineNr">1374 </span>  ]
<span id="L1375" class="LineNr">1375 </span>  run [
<span id="L1376" class="LineNr">1376 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1377" class="LineNr">1377 </span>  ]
<span id="L1378" class="LineNr">1378 </span>  screen-should-contain [
<span id="L1379" class="LineNr">1379 </span>   <span class="Constant"> .          .</span>
<span id="L1380" class="LineNr">1380 </span>   <span class="Constant"> .abc       .</span>
<span id="L1381" class="LineNr">1381 </span>   <span class="Constant"> .0def      .</span>
<span id="L1382" class="LineNr">1382 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1383" class="LineNr">1383 </span>   <span class="Constant"> .          .</span>
<span id="L1384" class="LineNr">1384 </span>  ]
<span id="L1385" class="LineNr">1385 </span>]
<span id="L1386" class="LineNr">1386 </span>
<span id="L1387" class="LineNr">1387 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L199'>&lt;handle-special-key&gt;</a></span> [
<span id="L1388" class="LineNr">1388 </span>  <span class="Delimiter">{</span>
<span id="L1389" class="LineNr">1389 </span>    move-to-next-line?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65516/down-arrow</span>
<span id="L1390" class="LineNr">1390 </span>    <span class="muControl">break-unless</span> move-to-next-line?
<span id="L1391" class="LineNr">1391 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L1392" class="LineNr">1392 </span>    go-render? <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1399'>move-to-next-line</a> editor, <a href='../081print.mu.html#L782'>screen-height</a>
<span id="L1393" class="LineNr">1393 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">4/down-arrow</span>
<span id="L1394" class="LineNr">1394 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L1395" class="LineNr">1395 </span>   <span class="muControl"> return</span>
<span id="L1396" class="LineNr">1396 </span>  <span class="Delimiter">}</span>
<span id="L1397" class="LineNr">1397 </span>]
<span id="L1398" class="LineNr">1398 </span>
<span id="L1399" class="LineNr">1399 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L1399'>move-to-next-line</a> editor:&amp;:editor, <a href='../081print.mu.html#L782'>screen-height</a>:num<span class="muRecipe"> -&gt; </span>go-render?:bool, editor:&amp;:editor [
<span id="L1400" class="LineNr">1400 </span>  <span class="Constant">local-scope</span>
<span id="L1401" class="LineNr">1401 </span>  <span class="Constant">load-inputs</span>
<span id="L1402" class="LineNr">1402 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L1403" class="LineNr">1403 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L1404" class="LineNr">1404 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L1405" class="LineNr">1405 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L1406" class="LineNr">1406 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L1407" class="LineNr">1407 </span>  last-line:num <span class="Special">&lt;-</span> subtract <a href='../081print.mu.html#L782'>screen-height</a>,<span class="Constant"> 1</span>
<span id="L1408" class="LineNr">1408 </span>  bottom:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">bottom:offset</span>
<span id="L1409" class="LineNr">1409 </span>  at-bottom-of-screen?:bool <span class="Special">&lt;-</span> greater-or-equal bottom, last-line
<span id="L1410" class="LineNr">1410 </span>  <span class="Delimiter">{</span>
<span id="L1411" class="LineNr">1411 </span>    <span class="muControl">break-if</span> before-cursor
<span id="L1412" class="LineNr">1412 </span>    <span class="Delimiter">{</span>
<span id="L1413" class="LineNr">1413 </span>      <span class="muControl">break-if</span> at-bottom-of-screen?
<span id="L1414" class="LineNr">1414 </span>     <span class="muControl"> return</span><span class="Constant"> false/don't-render</span>
<span id="L1415" class="LineNr">1415 </span>    <span class="Delimiter">}</span>
<span id="L1416" class="LineNr">1416 </span>    <span class="Delimiter">{</span>
<span id="L1417" class="LineNr">1417 </span>      <span class="muControl">break-unless</span> at-bottom-of-screen?
<span id="L1418" class="LineNr">1418 </span>     <span class="muControl"> jump</span> <span class="Constant">+try-to-scroll</span>
<span id="L1419" class="LineNr">1419 </span>    <span class="Delimiter">}</span>
<span id="L1420" class="LineNr">1420 </span>  <span class="Delimiter">}</span>
<span id="L1421" class="LineNr">1421 </span>  <a href='../065duplex_list.mu.html#L31'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-cursor
<span id="L1422" class="LineNr">1422 </span>  <span class="Delimiter">{</span>
<span id="L1423" class="LineNr">1423 </span>    <span class="muControl">break-if</span> <a href='../065duplex_list.mu.html#L31'>next</a>
<span id="L1424" class="LineNr">1424 </span>    <span class="Delimiter">{</span>
<span id="L1425" class="LineNr">1425 </span>      <span class="muControl">break-if</span> at-bottom-of-screen?
<span id="L1426" class="LineNr">1426 </span>     <span class="muControl"> return</span><span class="Constant"> false/don't-render</span>
<span id="L1427" class="LineNr">1427 </span>    <span class="Delimiter">}</span>
<span id="L1428" class="LineNr">1428 </span>    <span class="Delimiter">{</span>
<span id="L1429" class="LineNr">1429 </span>      <span class="muControl">break-unless</span> at-bottom-of-screen?
<span id="L1430" class="LineNr">1430 </span>     <span class="muControl"> jump</span> <span class="Constant">+try-to-scroll</span>
<span id="L1431" class="LineNr">1431 </span>    <span class="Delimiter">}</span>
<span id="L1432" class="LineNr">1432 </span>  <span class="Delimiter">}</span>
<span id="L1433" class="LineNr">1433 </span>  already-at-bottom?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-row, last-line
<span id="L1434" class="LineNr">1434 </span>  <span class="Delimiter">{</span>
<span id="L1435" class="LineNr">1435 </span>    <span class="Comment"># if cursor not at bottom, move it</span>
<span id="L1436" class="LineNr">1436 </span>    <span class="muControl">break-if</span> already-at-bottom?
<span id="L1437" class="LineNr">1437 </span>    target-column:num <span class="Special">&lt;-</span> copy cursor-column
<span id="L1438" class="LineNr">1438 </span>    <span class="Comment"># scan to start of next line</span>
<span id="L1439" class="LineNr">1439 </span>    <span class="Delimiter">{</span>
<span id="L1440" class="LineNr">1440 </span>      <a href='../065duplex_list.mu.html#L31'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-cursor
<span id="L1441" class="LineNr">1441 </span>      <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L31'>next</a>
<span id="L1442" class="LineNr">1442 </span>      done?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-column, right
<span id="L1443" class="LineNr">1443 </span>      <span class="muControl">break-if</span> done?
<span id="L1444" class="LineNr">1444 </span>      cursor-column <span class="Special">&lt;-</span> add cursor-column,<span class="Constant"> 1</span>
<span id="L1445" class="LineNr">1445 </span>      before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L31'>next</a>
<span id="L1446" class="LineNr">1446 </span>      c:char <span class="Special">&lt;-</span> get *next, <span class="Constant">value:offset</span>
<span id="L1447" class="LineNr">1447 </span>      at-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
<span id="L1448" class="LineNr">1448 </span>      <span class="muControl">break-if</span> at-newline?
<span id="L1449" class="LineNr">1449 </span>     <span class="muControl"> loop</span>
<span id="L1450" class="LineNr">1450 </span>    <span class="Delimiter">}</span>
<span id="L1451" class="LineNr">1451 </span>    <span class="Delimiter">{</span>
<span id="L1452" class="LineNr">1452 </span>      <span class="muControl">break-if</span> <a href='../065duplex_list.mu.html#L31'>next</a>
<span id="L1453" class="LineNr">1453 </span>      <span class="Delimiter">{</span>
<span id="L1454" class="LineNr">1454 </span>        <span class="muControl">break-if</span> at-bottom-of-screen?
<span id="L1455" class="LineNr">1455 </span>       <span class="muControl"> return</span><span class="Constant"> false/don't-render</span>
<span id="L1456" class="LineNr">1456 </span>      <span class="Delimiter">}</span>
<span id="L1457" class="LineNr">1457 </span>      <span class="Delimiter">{</span>
<span id="L1458" class="LineNr">1458 </span>        <span class="muControl">break-unless</span> at-bottom-of-screen?
<span id="L1459" class="LineNr">1459 </span>       <span class="muControl"> jump</span> <span class="Constant">+try-to-scroll</span>
<span id="L1460" class="LineNr">1460 </span>      <span class="Delimiter">}</span>
<span id="L1461" class="LineNr">1461 </span>    <span class="Delimiter">}</span>
<span id="L1462" class="LineNr">1462 </span>    cursor-row <span class="Special">&lt;-</span> add cursor-row,<span class="Constant"> 1</span>
<span id="L1463" class="LineNr">1463 </span>    cursor-column <span class="Special">&lt;-</span> copy left
<span id="L1464" class="LineNr">1464 </span>    <span class="Delimiter">{</span>
<span id="L1465" class="LineNr">1465 </span>      <a href='../065duplex_list.mu.html#L31'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-cursor
<span id="L1466" class="LineNr">1466 </span>      <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L31'>next</a>
<span id="L1467" class="LineNr">1467 </span>      c:char <span class="Special">&lt;-</span> get *next, <span class="Constant">value:offset</span>
<span id="L1468" class="LineNr">1468 </span>      at-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
<span id="L1469" class="LineNr">1469 </span>      <span class="muControl">break-if</span> at-newline?
<span id="L1470" class="LineNr">1470 </span>      done?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-column, target-column
<span id="L1471" class="LineNr">1471 </span>      <span class="muControl">break-if</span> done?
<span id="L1472" class="LineNr">1472 </span>      cursor-column <span class="Special">&lt;-</span> add cursor-column,<span class="Constant"> 1</span>
<span id="L1473" class="LineNr">1473 </span>      before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L31'>next</a>
<span id="L1474" class="LineNr">1474 </span>     <span class="muControl"> loop</span>
<span id="L1475" class="LineNr">1475 </span>    <span class="Delimiter">}</span>
<span id="L1476" class="LineNr">1476 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L1477" class="LineNr">1477 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L1478" class="LineNr">1478 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
<span id="L1479" class="LineNr">1479 </span>   <span class="muControl"> return</span><span class="Constant"> false/don't-render</span>
<span id="L1480" class="LineNr">1480 </span>  <span class="Delimiter">}</span>
<span id="L1481" class="LineNr">1481 </span><span class="Constant">  +try-to-scroll</span>
<span id="L1482" class="LineNr">1482 </span><span class="Constant">  &lt;scroll-down&gt;</span>
<span id="L1483" class="LineNr">1483 </span>  go-render? <span class="Special">&lt;-</span> copy<span class="Constant"> true</span>
<span id="L1484" class="LineNr">1484 </span>]
<span id="L1485" class="LineNr">1485 </span>
<span id="L1486" class="LineNr">1486 </span><span class="muScenario">scenario</span> editor-adjusts-column-at-next-line [
<span id="L1487" class="LineNr">1487 </span>  <span class="Constant">local-scope</span>
<span id="L1488" class="LineNr">1488 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1489" class="LineNr">1489 </span>  <span class="Comment"># second line is shorter than first</span>
<span id="L1490" class="LineNr">1490 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abcde</span>
<span id="L1491" class="LineNr">1491 </span><span class="Constant">fg</span>
<span id="L1492" class="LineNr">1492 </span><span class="Constant">hi]</span>
<span id="L1493" class="LineNr">1493 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1494" class="LineNr">1494 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1495" class="LineNr">1495 </span>  $clear-trace
<span id="L1496" class="LineNr">1496 </span>  <span class="Comment"># move to end of first line, then press down</span>
<span id="L1497" class="LineNr">1497 </span>  assume-console [
<span id="L1498" class="LineNr">1498 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 8</span>
<span id="L1499" class="LineNr">1499 </span>    press down-arrow
<span id="L1500" class="LineNr">1500 </span>  ]
<span id="L1501" class="LineNr">1501 </span>  run [
<span id="L1502" class="LineNr">1502 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1503" class="LineNr">1503 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1504" class="LineNr">1504 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1505" class="LineNr">1505 </span>  ]
<span id="L1506" class="LineNr">1506 </span>  <span class="Comment"># cursor doesn't go vertically down, it goes to end of shorter line</span>
<span id="L1507" class="LineNr">1507 </span>  memory-should-contain [
<span id="L1508" class="LineNr">1508 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1509" class="LineNr">1509 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1510" class="LineNr">1510 </span>  ]
<span id="L1511" class="LineNr">1511 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1512" class="LineNr">1512 </span>  assume-console [
<span id="L1513" class="LineNr">1513 </span>    type <span class="Constant">[0]</span>
<span id="L1514" class="LineNr">1514 </span>  ]
<span id="L1515" class="LineNr">1515 </span>  run [
<span id="L1516" class="LineNr">1516 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1517" class="LineNr">1517 </span>  ]
<span id="L1518" class="LineNr">1518 </span>  screen-should-contain [
<span id="L1519" class="LineNr">1519 </span>   <span class="Constant"> .          .</span>
<span id="L1520" class="LineNr">1520 </span>   <span class="Constant"> .abcde     .</span>
<span id="L1521" class="LineNr">1521 </span>   <span class="Constant"> .fg0       .</span>
<span id="L1522" class="LineNr">1522 </span>   <span class="Constant"> .hi        .</span>
<span id="L1523" class="LineNr">1523 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1524" class="LineNr">1524 </span>  ]
<span id="L1525" class="LineNr">1525 </span>]
<span id="L1526" class="LineNr">1526 </span>
<span id="L1527" class="LineNr">1527 </span><span class="muScenario">scenario</span> editor-moves-down-within-wrapped-line [
<span id="L1528" class="LineNr">1528 </span>  <span class="Constant">local-scope</span>
<span id="L1529" class="LineNr">1529 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1530" class="LineNr">1530 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abcdefghijklmno]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1531" class="LineNr">1531 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1532" class="LineNr">1532 </span>  screen-should-contain [
<span id="L1533" class="LineNr">1533 </span>   <span class="Constant"> .          .</span>
<span id="L1534" class="LineNr">1534 </span><span class="Constant">    .abcdefghi↩.</span>
<span id="L1535" class="LineNr">1535 </span>   <span class="Constant"> .jklmno    .</span>
<span id="L1536" class="LineNr">1536 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1537" class="LineNr">1537 </span>   <span class="Constant"> .          .</span>
<span id="L1538" class="LineNr">1538 </span>  ]
<span id="L1539" class="LineNr">1539 </span>  <span class="Comment"># position cursor on first screen line, but past end of second screen line</span>
<span id="L1540" class="LineNr">1540 </span>  assume-console [
<span id="L1541" class="LineNr">1541 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 8</span>
<span id="L1542" class="LineNr">1542 </span>    press down-arrow
<span id="L1543" class="LineNr">1543 </span>  ]
<span id="L1544" class="LineNr">1544 </span>  run [
<span id="L1545" class="LineNr">1545 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1546" class="LineNr">1546 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1547" class="LineNr">1547 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1548" class="LineNr">1548 </span>  ]
<span id="L1549" class="LineNr">1549 </span>  <span class="Comment"># cursor should be at end of second screen line</span>
<span id="L1550" class="LineNr">1550 </span>  memory-should-contain [
<span id="L1551" class="LineNr">1551 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1552" class="LineNr">1552 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 6</span>
<span id="L1553" class="LineNr">1553 </span>  ]
<span id="L1554" class="LineNr">1554 </span>]
<span id="L1555" class="LineNr">1555 </span>
<span id="L1556" class="LineNr">1556 </span><span class="Comment"># ctrl-a/home - move cursor to start of line</span>
<span id="L1557" class="LineNr">1557 </span>
<span id="L1558" class="LineNr">1558 </span><span class="muScenario">scenario</span> editor-moves-to-start-of-line-with-ctrl-a [
<span id="L1559" class="LineNr">1559 </span>  <span class="Constant">local-scope</span>
<span id="L1560" class="LineNr">1560 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1561" class="LineNr">1561 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L1562" class="LineNr">1562 </span><span class="Constant">456]</span>
<span id="L1563" class="LineNr">1563 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1564" class="LineNr">1564 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1565" class="LineNr">1565 </span>  $clear-trace
<span id="L1566" class="LineNr">1566 </span>  <span class="Comment"># start on second line, press ctrl-a</span>
<span id="L1567" class="LineNr">1567 </span>  assume-console [
<span id="L1568" class="LineNr">1568 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
<span id="L1569" class="LineNr">1569 </span>    press ctrl-a
<span id="L1570" class="LineNr">1570 </span>  ]
<span id="L1571" class="LineNr">1571 </span>  run [
<span id="L1572" class="LineNr">1572 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1573" class="LineNr">1573 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1574" class="LineNr">1574 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1575" class="LineNr">1575 </span>  ]
<span id="L1576" class="LineNr">1576 </span>  <span class="Comment"># cursor moves to start of line</span>
<span id="L1577" class="LineNr">1577 </span>  memory-should-contain [
<span id="L1578" class="LineNr">1578 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1579" class="LineNr">1579 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L1580" class="LineNr">1580 </span>  ]
<span id="L1581" class="LineNr">1581 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1582" class="LineNr">1582 </span>]
<span id="L1583" class="LineNr">1583 </span>
<span id="L1584" class="LineNr">1584 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L1585" class="LineNr">1585 </span>  <span class="Delimiter">{</span>
<span id="L1586" class="LineNr">1586 </span>    move-to-start-of-line?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">1/ctrl-a</span>
<span id="L1587" class="LineNr">1587 </span>    <span class="muControl">break-unless</span> move-to-start-of-line?
<span id="L1588" class="LineNr">1588 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L1589" class="LineNr">1589 </span>    <a href='003-shortcuts.mu.html#L1610'>move-to-start-of-screen-line</a> editor
<span id="L1590" class="LineNr">1590 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
<span id="L1591" class="LineNr">1591 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L1592" class="LineNr">1592 </span>   <span class="muControl"> return</span><span class="Constant"> false/don't-render</span>
<span id="L1593" class="LineNr">1593 </span>  <span class="Delimiter">}</span>
<span id="L1594" class="LineNr">1594 </span>]
<span id="L1595" class="LineNr">1595 </span>
<span id="L1596" class="LineNr">1596 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L199'>&lt;handle-special-key&gt;</a></span> [
<span id="L1597" class="LineNr">1597 </span>  <span class="Delimiter">{</span>
<span id="L1598" class="LineNr">1598 </span>    move-to-start-of-line?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65521/home</span>
<span id="L1599" class="LineNr">1599 </span>    <span class="muControl">break-unless</span> move-to-start-of-line?
<span id="L1600" class="LineNr">1600 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L1601" class="LineNr">1601 </span>    <a href='003-shortcuts.mu.html#L1610'>move-to-start-of-screen-line</a> editor
<span id="L1602" class="LineNr">1602 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
<span id="L1603" class="LineNr">1603 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L1604" class="LineNr">1604 </span>   <span class="muControl"> return</span><span class="Constant"> false/don't-render</span>
<span id="L1605" class="LineNr">1605 </span>  <span class="Delimiter">}</span>
<span id="L1606" class="LineNr">1606 </span>]
<span id="L1607" class="LineNr">1607 </span>
<span id="L1608" class="LineNr">1608 </span><span class="Comment"># handles wrapped lines</span>
<span id="L1609" class="LineNr">1609 </span><span class="Comment"># precondition: cursor-column should be in a consistent state</span>
<span id="L1610" class="LineNr">1610 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L1610'>move-to-start-of-screen-line</a> editor:&amp;:editor<span class="muRecipe"> -&gt; </span>editor:&amp;:editor [
<span id="L1611" class="LineNr">1611 </span>  <span class="Constant">local-scope</span>
<span id="L1612" class="LineNr">1612 </span>  <span class="Constant">load-inputs</span>
<span id="L1613" class="LineNr">1613 </span>  <span class="Comment"># update cursor column</span>
<span id="L1614" class="LineNr">1614 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L1615" class="LineNr">1615 </span>  col:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L1616" class="LineNr">1616 </span>  <span class="Comment"># update before-cursor</span>
<span id="L1617" class="LineNr">1617 </span>  curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L1618" class="LineNr">1618 </span>  <span class="Comment"># while not at start of line, move</span>
<span id="L1619" class="LineNr">1619 </span>  <span class="Delimiter">{</span>
<span id="L1620" class="LineNr">1620 </span>    done?:bool <span class="Special">&lt;-</span> equal col, left
<span id="L1621" class="LineNr">1621 </span>    <span class="muControl">break-if</span> done?
<span id="L1622" class="LineNr">1622 </span>    assert curr, <span class="Constant">[move-to-start-of-line tried to move before start of text]</span>
<span id="L1623" class="LineNr">1623 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L38'>prev</a> curr
<span id="L1624" class="LineNr">1624 </span>    col <span class="Special">&lt;-</span> subtract col,<span class="Constant"> 1</span>
<span id="L1625" class="LineNr">1625 </span>   <span class="muControl"> loop</span>
<span id="L1626" class="LineNr">1626 </span>  <span class="Delimiter">}</span>
<span id="L1627" class="LineNr">1627 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, col
<span id="L1628" class="LineNr">1628 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, curr
<span id="L1629" class="LineNr">1629 </span>]
<span id="L1630" class="LineNr">1630 </span>
<span id="L1631" class="LineNr">1631 </span><span class="muScenario">scenario</span> editor-moves-to-start-of-line-with-ctrl-a-2 [
<span id="L1632" class="LineNr">1632 </span>  <span class="Constant">local-scope</span>
<span id="L1633" class="LineNr">1633 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1634" class="LineNr">1634 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L1635" class="LineNr">1635 </span><span class="Constant">456]</span>
<span id="L1636" class="LineNr">1636 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1637" class="LineNr">1637 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1638" class="LineNr">1638 </span>  $clear-trace
<span id="L1639" class="LineNr">1639 </span>  <span class="Comment"># start on first line (no newline before), press ctrl-a</span>
<span id="L1640" class="LineNr">1640 </span>  assume-console [
<span id="L1641" class="LineNr">1641 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
<span id="L1642" class="LineNr">1642 </span>    press ctrl-a
<span id="L1643" class="LineNr">1643 </span>  ]
<span id="L1644" class="LineNr">1644 </span>  run [
<span id="L1645" class="LineNr">1645 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1646" class="LineNr">1646 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1647" class="LineNr">1647 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1648" class="LineNr">1648 </span>  ]
<span id="L1649" class="LineNr">1649 </span>  <span class="Comment"># cursor moves to start of line</span>
<span id="L1650" class="LineNr">1650 </span>  memory-should-contain [
<span id="L1651" class="LineNr">1651 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1652" class="LineNr">1652 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L1653" class="LineNr">1653 </span>  ]
<span id="L1654" class="LineNr">1654 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1655" class="LineNr">1655 </span>]
<span id="L1656" class="LineNr">1656 </span>
<span id="L1657" class="LineNr">1657 </span><span class="muScenario">scenario</span> editor-moves-to-start-of-line-with-home [
<span id="L1658" class="LineNr">1658 </span>  <span class="Constant">local-scope</span>
<span id="L1659" class="LineNr">1659 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1660" class="LineNr">1660 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L1661" class="LineNr">1661 </span><span class="Constant">456]</span>
<span id="L1662" class="LineNr">1662 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1663" class="LineNr">1663 </span>  $clear-trace
<span id="L1664" class="LineNr">1664 </span>  <span class="Comment"># start on second line, press 'home'</span>
<span id="L1665" class="LineNr">1665 </span>  assume-console [
<span id="L1666" class="LineNr">1666 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
<span id="L1667" class="LineNr">1667 </span>    press home
<span id="L1668" class="LineNr">1668 </span>  ]
<span id="L1669" class="LineNr">1669 </span>  run [
<span id="L1670" class="LineNr">1670 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1671" class="LineNr">1671 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1672" class="LineNr">1672 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1673" class="LineNr">1673 </span>  ]
<span id="L1674" class="LineNr">1674 </span>  <span class="Comment"># cursor moves to start of line</span>
<span id="L1675" class="LineNr">1675 </span>  memory-should-contain [
<span id="L1676" class="LineNr">1676 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1677" class="LineNr">1677 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L1678" class="LineNr">1678 </span>  ]
<span id="L1679" class="LineNr">1679 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1680" class="LineNr">1680 </span>]
<span id="L1681" class="LineNr">1681 </span>
<span id="L1682" class="LineNr">1682 </span><span class="muScenario">scenario</span> editor-moves-to-start-of-line-with-home-2 [
<span id="L1683" class="LineNr">1683 </span>  <span class="Constant">local-scope</span>
<span id="L1684" class="LineNr">1684 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1685" class="LineNr">1685 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L1686" class="LineNr">1686 </span><span class="Constant">456]</span>
<span id="L1687" class="LineNr">1687 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1688" class="LineNr">1688 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1689" class="LineNr">1689 </span>  $clear-trace
<span id="L1690" class="LineNr">1690 </span>  <span class="Comment"># start on first line (no newline before), press 'home'</span>
<span id="L1691" class="LineNr">1691 </span>  assume-console [
<span id="L1692" class="LineNr">1692 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
<span id="L1693" class="LineNr">1693 </span>    press home
<span id="L1694" class="LineNr">1694 </span>  ]
<span id="L1695" class="LineNr">1695 </span>  run [
<span id="L1696" class="LineNr">1696 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1697" class="LineNr">1697 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1698" class="LineNr">1698 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1699" class="LineNr">1699 </span>  ]
<span id="L1700" class="LineNr">1700 </span>  <span class="Comment"># cursor moves to start of line</span>
<span id="L1701" class="LineNr">1701 </span>  memory-should-contain [
<span id="L1702" class="LineNr">1702 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1703" class="LineNr">1703 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L1704" class="LineNr">1704 </span>  ]
<span id="L1705" class="LineNr">1705 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1706" class="LineNr">1706 </span>]
<span id="L1707" class="LineNr">1707 </span>
<span id="L1708" class="LineNr">1708 </span><span class="muScenario">scenario</span> editor-moves-to-start-of-screen-line-with-ctrl-a [
<span id="L1709" class="LineNr">1709 </span>  <span class="Constant">local-scope</span>
<span id="L1710" class="LineNr">1710 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1711" class="LineNr">1711 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[123456]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L1712" class="LineNr">1712 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1713" class="LineNr">1713 </span>  screen-should-contain [
<span id="L1714" class="LineNr">1714 </span>   <span class="Constant"> .          .</span>
<span id="L1715" class="LineNr">1715 </span>   <span class="Constant"> .1234↩     .</span>
<span id="L1716" class="LineNr">1716 </span>   <span class="Constant"> .56        .</span>
<span id="L1717" class="LineNr">1717 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L1718" class="LineNr">1718 </span>   <span class="Constant"> .          .</span>
<span id="L1719" class="LineNr">1719 </span>  ]
<span id="L1720" class="LineNr">1720 </span>  $clear-trace
<span id="L1721" class="LineNr">1721 </span>  <span class="Comment"># start on second line, press ctrl-a then up</span>
<span id="L1722" class="LineNr">1722 </span>  assume-console [
<span id="L1723" class="LineNr">1723 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
<span id="L1724" class="LineNr">1724 </span>    press ctrl-a
<span id="L1725" class="LineNr">1725 </span>    press up-arrow
<span id="L1726" class="LineNr">1726 </span>  ]
<span id="L1727" class="LineNr">1727 </span>  run [
<span id="L1728" class="LineNr">1728 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1729" class="LineNr">1729 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1730" class="LineNr">1730 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1731" class="LineNr">1731 </span>  ]
<span id="L1732" class="LineNr">1732 </span>  <span class="Comment"># cursor moves to start of first line</span>
<span id="L1733" class="LineNr">1733 </span>  memory-should-contain [
<span id="L1734" class="LineNr">1734 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># cursor-row</span>
<span id="L1735" class="LineNr">1735 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># cursor-column</span>
<span id="L1736" class="LineNr">1736 </span>  ]
<span id="L1737" class="LineNr">1737 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1738" class="LineNr">1738 </span>  <span class="Comment"># make sure before-cursor is in sync</span>
<span id="L1739" class="LineNr">1739 </span>  assume-console [
<span id="L1740" class="LineNr">1740 </span>    type <span class="Constant">[a]</span>
<span id="L1741" class="LineNr">1741 </span>  ]
<span id="L1742" class="LineNr">1742 </span>  run [
<span id="L1743" class="LineNr">1743 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1744" class="LineNr">1744 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1745" class="LineNr">1745 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1746" class="LineNr">1746 </span>  ]
<span id="L1747" class="LineNr">1747 </span>  screen-should-contain [
<span id="L1748" class="LineNr">1748 </span>   <span class="Constant"> .          .</span>
<span id="L1749" class="LineNr">1749 </span>   <span class="Constant"> .a123↩     .</span>
<span id="L1750" class="LineNr">1750 </span>   <span class="Constant"> .456       .</span>
<span id="L1751" class="LineNr">1751 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L1752" class="LineNr">1752 </span>   <span class="Constant"> .          .</span>
<span id="L1753" class="LineNr">1753 </span>  ]
<span id="L1754" class="LineNr">1754 </span>  memory-should-contain [
<span id="L1755" class="LineNr">1755 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># cursor-row</span>
<span id="L1756" class="LineNr">1756 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># cursor-column</span>
<span id="L1757" class="LineNr">1757 </span>  ]
<span id="L1758" class="LineNr">1758 </span>]
<span id="L1759" class="LineNr">1759 </span>
<span id="L1760" class="LineNr">1760 </span><span class="Comment"># ctrl-e/end - move cursor to end of line</span>
<span id="L1761" class="LineNr">1761 </span>
<span id="L1762" class="LineNr">1762 </span><span class="muScenario">scenario</span> editor-moves-to-end-of-line-with-ctrl-e [
<span id="L1763" class="LineNr">1763 </span>  <span class="Constant">local-scope</span>
<span id="L1764" class="LineNr">1764 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1765" class="LineNr">1765 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L1766" class="LineNr">1766 </span><span class="Constant">456]</span>
<span id="L1767" class="LineNr">1767 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1768" class="LineNr">1768 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1769" class="LineNr">1769 </span>  $clear-trace
<span id="L1770" class="LineNr">1770 </span>  <span class="Comment"># start on first line, press ctrl-e</span>
<span id="L1771" class="LineNr">1771 </span>  assume-console [
<span id="L1772" class="LineNr">1772 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
<span id="L1773" class="LineNr">1773 </span>    press ctrl-e
<span id="L1774" class="LineNr">1774 </span>  ]
<span id="L1775" class="LineNr">1775 </span>  run [
<span id="L1776" class="LineNr">1776 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1777" class="LineNr">1777 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1778" class="LineNr">1778 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1779" class="LineNr">1779 </span>  ]
<span id="L1780" class="LineNr">1780 </span>  <span class="Comment"># cursor moves to end of line</span>
<span id="L1781" class="LineNr">1781 </span>  memory-should-contain [
<span id="L1782" class="LineNr">1782 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1783" class="LineNr">1783 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L1784" class="LineNr">1784 </span>  ]
<span id="L1785" class="LineNr">1785 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1786" class="LineNr">1786 </span>  <span class="Comment"># editor inserts future characters at cursor</span>
<span id="L1787" class="LineNr">1787 </span>  assume-console [
<span id="L1788" class="LineNr">1788 </span>    type <span class="Constant">[z]</span>
<span id="L1789" class="LineNr">1789 </span>  ]
<span id="L1790" class="LineNr">1790 </span>  run [
<span id="L1791" class="LineNr">1791 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1792" class="LineNr">1792 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1793" class="LineNr">1793 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1794" class="LineNr">1794 </span>  ]
<span id="L1795" class="LineNr">1795 </span>  memory-should-contain [
<span id="L1796" class="LineNr">1796 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1797" class="LineNr">1797 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
<span id="L1798" class="LineNr">1798 </span>  ]
<span id="L1799" class="LineNr">1799 </span>  screen-should-contain [
<span id="L1800" class="LineNr">1800 </span>   <span class="Constant"> .          .</span>
<span id="L1801" class="LineNr">1801 </span>   <span class="Constant"> .123z      .</span>
<span id="L1802" class="LineNr">1802 </span>   <span class="Constant"> .456       .</span>
<span id="L1803" class="LineNr">1803 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1804" class="LineNr">1804 </span>   <span class="Constant"> .          .</span>
<span id="L1805" class="LineNr">1805 </span>  ]
<span id="L1806" class="LineNr">1806 </span>  check-trace-count-for-label<span class="Constant"> 1</span>, <span class="Constant">[print-character]</span>
<span id="L1807" class="LineNr">1807 </span>]
<span id="L1808" class="LineNr">1808 </span>
<span id="L1809" class="LineNr">1809 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L1810" class="LineNr">1810 </span>  <span class="Delimiter">{</span>
<span id="L1811" class="LineNr">1811 </span>    move-to-end-of-line?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">5/ctrl-e</span>
<span id="L1812" class="LineNr">1812 </span>    <span class="muControl">break-unless</span> move-to-end-of-line?
<span id="L1813" class="LineNr">1813 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L1814" class="LineNr">1814 </span>    <a href='003-shortcuts.mu.html#L1833'>move-to-end-of-line</a> editor
<span id="L1815" class="LineNr">1815 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
<span id="L1816" class="LineNr">1816 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L1817" class="LineNr">1817 </span>   <span class="muControl"> return</span><span class="Constant"> false/don't-render</span>
<span id="L1818" class="LineNr">1818 </span>  <span class="Delimiter">}</span>
<span id="L1819" class="LineNr">1819 </span>]
<span id="L1820" class="LineNr">1820 </span>
<span id="L1821" class="LineNr">1821 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L199'>&lt;handle-special-key&gt;</a></span> [
<span id="L1822" class="LineNr">1822 </span>  <span class="Delimiter">{</span>
<span id="L1823" class="LineNr">1823 </span>    move-to-end-of-line?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65520/end</span>
<span id="L1824" class="LineNr">1824 </span>    <span class="muControl">break-unless</span> move-to-end-of-line?
<span id="L1825" class="LineNr">1825 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L1826" class="LineNr">1826 </span>    <a href='003-shortcuts.mu.html#L1833'>move-to-end-of-line</a> editor
<span id="L1827" class="LineNr">1827 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
<span id="L1828" class="LineNr">1828 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L1829" class="LineNr">1829 </span>   <span class="muControl"> return</span><span class="Constant"> false/don't-render</span>
<span id="L1830" class="LineNr">1830 </span>  <span class="Delimiter">}</span>
<span id="L1831" class="LineNr">1831 </span>]
<span id="L1832" class="LineNr">1832 </span>
<span id="L1833" class="LineNr">1833 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L1833'>move-to-end-of-line</a> editor:&amp;:editor<span class="muRecipe"> -&gt; </span>editor:&amp;:editor [
<span id="L1834" class="LineNr">1834 </span>  <span class="Constant">local-scope</span>
<span id="L1835" class="LineNr">1835 </span>  <span class="Constant">load-inputs</span>
<span id="L1836" class="LineNr">1836 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L1837" class="LineNr">1837 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L1838" class="LineNr">1838 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L1839" class="LineNr">1839 </span>  <span class="Comment"># while not at end of line, move</span>
<span id="L1840" class="LineNr">1840 </span>  <span class="Delimiter">{</span>
<span id="L1841" class="LineNr">1841 </span>    <a href='../065duplex_list.mu.html#L31'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-cursor
<span id="L1842" class="LineNr">1842 </span>    <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L31'>next</a>  <span class="Comment"># end of text</span>
<span id="L1843" class="LineNr">1843 </span>    nextc:char <span class="Special">&lt;-</span> get *next, <span class="Constant">value:offset</span>
<span id="L1844" class="LineNr">1844 </span>    at-end-of-line?:bool <span class="Special">&lt;-</span> equal nextc, <span class="Constant">10/newline</span>
<span id="L1845" class="LineNr">1845 </span>    <span class="muControl">break-if</span> at-end-of-line?
<span id="L1846" class="LineNr">1846 </span>    cursor-column <span class="Special">&lt;-</span> add cursor-column,<span class="Constant"> 1</span>
<span id="L1847" class="LineNr">1847 </span>    at-right?:bool <span class="Special">&lt;-</span> equal cursor-column, right
<span id="L1848" class="LineNr">1848 </span>    <span class="muControl">break-if</span> at-right?
<span id="L1849" class="LineNr">1849 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L1850" class="LineNr">1850 </span>    before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L31'>next</a>
<span id="L1851" class="LineNr">1851 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L1852" class="LineNr">1852 </span>   <span class="muControl"> loop</span>
<span id="L1853" class="LineNr">1853 </span>  <span class="Delimiter">}</span>
<span id="L1854" class="LineNr">1854 </span>]
<span id="L1855" class="LineNr">1855 </span>
<span id="L1856" class="LineNr">1856 </span><span class="muScenario">scenario</span> editor-moves-to-end-of-line-with-ctrl-e-2 [
<span id="L1857" class="LineNr">1857 </span>  <span class="Constant">local-scope</span>
<span id="L1858" class="LineNr">1858 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1859" class="LineNr">1859 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L1860" class="LineNr">1860 </span><span class="Constant">456]</span>
<span id="L1861" class="LineNr">1861 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1862" class="LineNr">1862 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1863" class="LineNr">1863 </span>  $clear-trace
<span id="L1864" class="LineNr">1864 </span>  <span class="Comment"># start on second line (no newline after), press ctrl-e</span>
<span id="L1865" class="LineNr">1865 </span>  assume-console [
<span id="L1866" class="LineNr">1866 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
<span id="L1867" class="LineNr">1867 </span>    press ctrl-e
<span id="L1868" class="LineNr">1868 </span>  ]
<span id="L1869" class="LineNr">1869 </span>  run [
<span id="L1870" class="LineNr">1870 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1871" class="LineNr">1871 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1872" class="LineNr">1872 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1873" class="LineNr">1873 </span>  ]
<span id="L1874" class="LineNr">1874 </span>  <span class="Comment"># cursor moves to end of line</span>
<span id="L1875" class="LineNr">1875 </span>  memory-should-contain [
<span id="L1876" class="LineNr">1876 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1877" class="LineNr">1877 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L1878" class="LineNr">1878 </span>  ]
<span id="L1879" class="LineNr">1879 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1880" class="LineNr">1880 </span>]
<span id="L1881" class="LineNr">1881 </span>
<span id="L1882" class="LineNr">1882 </span><span class="muScenario">scenario</span> editor-moves-to-end-of-line-with-end [
<span id="L1883" class="LineNr">1883 </span>  <span class="Constant">local-scope</span>
<span id="L1884" class="LineNr">1884 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1885" class="LineNr">1885 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L1886" class="LineNr">1886 </span><span class="Constant">456]</span>
<span id="L1887" class="LineNr">1887 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1888" class="LineNr">1888 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1889" class="LineNr">1889 </span>  $clear-trace
<span id="L1890" class="LineNr">1890 </span>  <span class="Comment"># start on first line, press 'end'</span>
<span id="L1891" class="LineNr">1891 </span>  assume-console [
<span id="L1892" class="LineNr">1892 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
<span id="L1893" class="LineNr">1893 </span>    press end
<span id="L1894" class="LineNr">1894 </span>  ]
<span id="L1895" class="LineNr">1895 </span>  run [
<span id="L1896" class="LineNr">1896 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1897" class="LineNr">1897 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1898" class="LineNr">1898 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1899" class="LineNr">1899 </span>  ]
<span id="L1900" class="LineNr">1900 </span>  <span class="Comment"># cursor moves to end of line</span>
<span id="L1901" class="LineNr">1901 </span>  memory-should-contain [
<span id="L1902" class="LineNr">1902 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1903" class="LineNr">1903 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L1904" class="LineNr">1904 </span>  ]
<span id="L1905" class="LineNr">1905 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1906" class="LineNr">1906 </span>]
<span id="L1907" class="LineNr">1907 </span>
<span id="L1908" class="LineNr">1908 </span><span class="muScenario">scenario</span> editor-moves-to-end-of-line-with-end-2 [
<span id="L1909" class="LineNr">1909 </span>  <span class="Constant">local-scope</span>
<span id="L1910" class="LineNr">1910 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1911" class="LineNr">1911 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L1912" class="LineNr">1912 </span><span class="Constant">456]</span>
<span id="L1913" class="LineNr">1913 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1914" class="LineNr">1914 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1915" class="LineNr">1915 </span>  $clear-trace
<span id="L1916" class="LineNr">1916 </span>  <span class="Comment"># start on second line (no newline after), press 'end'</span>
<span id="L1917" class="LineNr">1917 </span>  assume-console [
<span id="L1918" class="LineNr">1918 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
<span id="L1919" class="LineNr">1919 </span>    press end
<span id="L1920" class="LineNr">1920 </span>  ]
<span id="L1921" class="LineNr">1921 </span>  run [
<span id="L1922" class="LineNr">1922 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1923" class="LineNr">1923 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1924" class="LineNr">1924 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1925" class="LineNr">1925 </span>  ]
<span id="L1926" class="LineNr">1926 </span>  <span class="Comment"># cursor moves to end of line</span>
<span id="L1927" class="LineNr">1927 </span>  memory-should-contain [
<span id="L1928" class="LineNr">1928 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L1929" class="LineNr">1929 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L1930" class="LineNr">1930 </span>  ]
<span id="L1931" class="LineNr">1931 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1932" class="LineNr">1932 </span>]
<span id="L1933" class="LineNr">1933 </span>
<span id="L1934" class="LineNr">1934 </span><span class="muScenario">scenario</span> editor-moves-to-end-of-wrapped-line [
<span id="L1935" class="LineNr">1935 </span>  <span class="Constant">local-scope</span>
<span id="L1936" class="LineNr">1936 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1937" class="LineNr">1937 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123456</span>
<span id="L1938" class="LineNr">1938 </span><span class="Constant">789]</span>
<span id="L1939" class="LineNr">1939 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L1940" class="LineNr">1940 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1941" class="LineNr">1941 </span>  $clear-trace
<span id="L1942" class="LineNr">1942 </span>  <span class="Comment"># start on first line, press 'end'</span>
<span id="L1943" class="LineNr">1943 </span>  assume-console [
<span id="L1944" class="LineNr">1944 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
<span id="L1945" class="LineNr">1945 </span>    press end
<span id="L1946" class="LineNr">1946 </span>  ]
<span id="L1947" class="LineNr">1947 </span>  run [
<span id="L1948" class="LineNr">1948 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1949" class="LineNr">1949 </span>    10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L1950" class="LineNr">1950 </span>    11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L1951" class="LineNr">1951 </span>  ]
<span id="L1952" class="LineNr">1952 </span>  <span class="Comment"># cursor moves to end of line</span>
<span id="L1953" class="LineNr">1953 </span>  memory-should-contain [
<span id="L1954" class="LineNr">1954 </span>   <span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L1955" class="LineNr">1955 </span>   <span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L1956" class="LineNr">1956 </span>  ]
<span id="L1957" class="LineNr">1957 </span>  <span class="Comment"># no prints</span>
<span id="L1958" class="LineNr">1958 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L1959" class="LineNr">1959 </span>  <span class="Comment"># before-cursor is also consistent</span>
<span id="L1960" class="LineNr">1960 </span>  assume-console [
<span id="L1961" class="LineNr">1961 </span>    type <span class="Constant">[a]</span>
<span id="L1962" class="LineNr">1962 </span>  ]
<span id="L1963" class="LineNr">1963 </span>  run [
<span id="L1964" class="LineNr">1964 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1965" class="LineNr">1965 </span>  ]
<span id="L1966" class="LineNr">1966 </span>  screen-should-contain [
<span id="L1967" class="LineNr">1967 </span>   <span class="Constant"> .          .</span>
<span id="L1968" class="LineNr">1968 </span>   <span class="Constant"> .123a↩     .</span>
<span id="L1969" class="LineNr">1969 </span>   <span class="Constant"> .456       .</span>
<span id="L1970" class="LineNr">1970 </span>   <span class="Constant"> .789       .</span>
<span id="L1971" class="LineNr">1971 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L1972" class="LineNr">1972 </span>  ]
<span id="L1973" class="LineNr">1973 </span>]
<span id="L1974" class="LineNr">1974 </span>
<span id="L1975" class="LineNr">1975 </span><span class="Comment"># ctrl-u - delete text from start of line until (but not at) cursor</span>
<span id="L1976" class="LineNr">1976 </span>
<span id="L1977" class="LineNr">1977 </span><span class="muScenario">scenario</span> editor-deletes-to-start-of-line-with-ctrl-u [
<span id="L1978" class="LineNr">1978 </span>  <span class="Constant">local-scope</span>
<span id="L1979" class="LineNr">1979 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L1980" class="LineNr">1980 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L1981" class="LineNr">1981 </span><span class="Constant">456]</span>
<span id="L1982" class="LineNr">1982 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L1983" class="LineNr">1983 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L1984" class="LineNr">1984 </span>  $clear-trace
<span id="L1985" class="LineNr">1985 </span>  <span class="Comment"># start on second line, press ctrl-u</span>
<span id="L1986" class="LineNr">1986 </span>  assume-console [
<span id="L1987" class="LineNr">1987 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 2</span>
<span id="L1988" class="LineNr">1988 </span>    press ctrl-u
<span id="L1989" class="LineNr">1989 </span>  ]
<span id="L1990" class="LineNr">1990 </span>  run [
<span id="L1991" class="LineNr">1991 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L1992" class="LineNr">1992 </span>  ]
<span id="L1993" class="LineNr">1993 </span>  <span class="Comment"># cursor deletes to start of line</span>
<span id="L1994" class="LineNr">1994 </span>  screen-should-contain [
<span id="L1995" class="LineNr">1995 </span>   <span class="Constant"> .          .</span>
<span id="L1996" class="LineNr">1996 </span>   <span class="Constant"> .123       .</span>
<span id="L1997" class="LineNr">1997 </span>   <span class="Constant"> .6         .</span>
<span id="L1998" class="LineNr">1998 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L1999" class="LineNr">1999 </span>   <span class="Constant"> .          .</span>
<span id="L2000" class="LineNr">2000 </span>  ]
<span id="L2001" class="LineNr">2001 </span>  check-trace-count-for-label<span class="Constant"> 10</span>, <span class="Constant">[print-character]</span>
<span id="L2002" class="LineNr">2002 </span>]
<span id="L2003" class="LineNr">2003 </span>
<span id="L2004" class="LineNr">2004 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L2005" class="LineNr">2005 </span>  <span class="Delimiter">{</span>
<span id="L2006" class="LineNr">2006 </span>    delete-to-start-of-line?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">21/ctrl-u</span>
<span id="L2007" class="LineNr">2007 </span>    <span class="muControl">break-unless</span> delete-to-start-of-line?
<span id="L2008" class="LineNr">2008 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L2008'>&lt;begin-delete-to-start-of-line&gt;</a></span>
<span id="L2009" class="LineNr">2009 </span>    deleted-cells:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2051'>delete-to-start-of-line</a> editor
<span id="L2010" class="LineNr">2010 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L2010'>&lt;end-delete-to-start-of-line&gt;</a></span>
<span id="L2011" class="LineNr">2011 </span>    go-render?:bool <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2016'>minimal-render-for-ctrl-u</a> <a href='../081print.mu.html#L16'>screen</a>, editor, deleted-cells
<span id="L2012" class="LineNr">2012 </span>   <span class="muControl"> return</span>
<span id="L2013" class="LineNr">2013 </span>  <span class="Delimiter">}</span>
<span id="L2014" class="LineNr">2014 </span>]
<span id="L2015" class="LineNr">2015 </span>
<span id="L2016" class="LineNr">2016 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L2016'>minimal-render-for-ctrl-u</a> <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a>, editor:&amp;:editor, deleted-cells:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char<span class="muRecipe"> -&gt; </span>go-render?:bool, <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a> [
<span id="L2017" class="LineNr">2017 </span>  <span class="Constant">local-scope</span>
<span id="L2018" class="LineNr">2018 </span>  <span class="Constant">load-inputs</span>
<span id="L2019" class="LineNr">2019 </span>  curr-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L2020" class="LineNr">2020 </span>  <span class="Comment"># accumulate the current line as text and render it</span>
<span id="L2021" class="LineNr">2021 </span>  buf:&amp;:<a href='../061text.mu.html#L120'>buffer</a>:char <span class="Special">&lt;-</span> <a href='../061text.mu.html#L125'>new-buffer</a><span class="Constant"> 30</span>  <span class="Comment"># accumulator for the text we need to render</span>
<span id="L2022" class="LineNr">2022 </span>  curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L2023" class="LineNr">2023 </span>  i:num <span class="Special">&lt;-</span> copy curr-column
<span id="L2024" class="LineNr">2024 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L2025" class="LineNr">2025 </span>  <span class="Delimiter">{</span>
<span id="L2026" class="LineNr">2026 </span>    <span class="Comment"># if we have a wrapped line, give up and render the whole screen</span>
<span id="L2027" class="LineNr">2027 </span>    wrap?:bool <span class="Special">&lt;-</span> greater-or-equal i, right
<span id="L2028" class="LineNr">2028 </span>    <span class="muControl">return-if</span> wrap?,<span class="Constant"> true/go-render</span>
<span id="L2029" class="LineNr">2029 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> curr
<span id="L2030" class="LineNr">2030 </span>    <span class="muControl">break-unless</span> curr
<span id="L2031" class="LineNr">2031 </span>    c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
<span id="L2032" class="LineNr">2032 </span>    b:bool <span class="Special">&lt;-</span> equal c,<span class="Constant"> 10</span>
<span id="L2033" class="LineNr">2033 </span>    <span class="muControl">break-if</span> b
<span id="L2034" class="LineNr">2034 </span>    buf <span class="Special">&lt;-</span> append buf, c
<span id="L2035" class="LineNr">2035 </span>    i <span class="Special">&lt;-</span> add i,<span class="Constant"> 1</span>
<span id="L2036" class="LineNr">2036 </span>   <span class="muControl"> loop</span>
<span id="L2037" class="LineNr">2037 </span>  <span class="Delimiter">}</span>
<span id="L2038" class="LineNr">2038 </span>  <span class="Comment"># if the line used to be wrapped, give up and render the whole screen</span>
<span id="L2039" class="LineNr">2039 </span>  num-deleted-cells:num <span class="Special">&lt;-</span> length deleted-cells
<span id="L2040" class="LineNr">2040 </span>  old-row-len:num <span class="Special">&lt;-</span> add i, num-deleted-cells
<span id="L2041" class="LineNr">2041 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L2042" class="LineNr">2042 </span>  end:num <span class="Special">&lt;-</span> subtract right, left
<span id="L2043" class="LineNr">2043 </span>  wrap?:bool <span class="Special">&lt;-</span> greater-or-equal old-row-len, end
<span id="L2044" class="LineNr">2044 </span>  <span class="muControl">return-if</span> wrap?,<span class="Constant"> true/go-render</span>
<span id="L2045" class="LineNr">2045 </span>  curr-line:text <span class="Special">&lt;-</span> <a href='../061text.mu.html#L338'>buffer-to-array</a> buf
<span id="L2046" class="LineNr">2046 </span>  curr-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L2047" class="LineNr">2047 </span>  <a href='003-shortcuts.mu.html#L2107'>render-code</a> <a href='../081print.mu.html#L16'>screen</a>, curr-line, curr-column, right, curr-row
<span id="L2048" class="LineNr">2048 </span> <span class="muControl"> return</span><span class="Constant"> false/dont-render</span>
<span id="L2049" class="LineNr">2049 </span>]
<span id="L2050" class="LineNr">2050 </span>
<span id="L2051" class="LineNr">2051 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L2051'>delete-to-start-of-line</a> editor:&amp;:editor<span class="muRecipe"> -&gt; </span>result:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char, editor:&amp;:editor [
<span id="L2052" class="LineNr">2052 </span>  <span class="Constant">local-scope</span>
<span id="L2053" class="LineNr">2053 </span>  <span class="Constant">load-inputs</span>
<span id="L2054" class="LineNr">2054 </span>  <span class="Comment"># compute range to delete</span>
<span id="L2055" class="LineNr">2055 </span>  init:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
<span id="L2056" class="LineNr">2056 </span>  top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L2057" class="LineNr">2057 </span>  update-top-of-screen?:bool <span class="Special">&lt;-</span> copy<span class="Constant"> false</span>
<span id="L2058" class="LineNr">2058 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L2059" class="LineNr">2059 </span>  start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy before-cursor
<span id="L2060" class="LineNr">2060 </span>  end:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-cursor
<span id="L2061" class="LineNr">2061 </span>  <span class="Delimiter">{</span>
<span id="L2062" class="LineNr">2062 </span>    at-start-of-text?:bool <span class="Special">&lt;-</span> equal start, init
<span id="L2063" class="LineNr">2063 </span>    <span class="muControl">break-if</span> at-start-of-text?
<span id="L2064" class="LineNr">2064 </span>    curr:char <span class="Special">&lt;-</span> get *start, <span class="Constant">value:offset</span>
<span id="L2065" class="LineNr">2065 </span>    at-start-of-line?:bool <span class="Special">&lt;-</span> equal curr, <span class="Constant">10/newline</span>
<span id="L2066" class="LineNr">2066 </span>    <span class="muControl">break-if</span> at-start-of-line?
<span id="L2067" class="LineNr">2067 </span>    <span class="Comment"># if we went past top-of-screen, make a note to update it as well</span>
<span id="L2068" class="LineNr">2068 </span>    at-top-of-screen?:bool <span class="Special">&lt;-</span> equal start, top-of-screen
<span id="L2069" class="LineNr">2069 </span>    update-top-of-screen?:bool <span class="Special">&lt;-</span> or update-top-of-screen?, at-top-of-screen?
<span id="L2070" class="LineNr">2070 </span>    start <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L38'>prev</a> start
<span id="L2071" class="LineNr">2071 </span>    assert start, <span class="Constant">[delete-to-start-of-line tried to move before start of text]</span>
<span id="L2072" class="LineNr">2072 </span>   <span class="muControl"> loop</span>
<span id="L2073" class="LineNr">2073 </span>  <span class="Delimiter">}</span>
<span id="L2074" class="LineNr">2074 </span>  <span class="Comment"># snip it out</span>
<span id="L2075" class="LineNr">2075 </span>  result:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> start
<span id="L2076" class="LineNr">2076 </span>  <a href='../065duplex_list.mu.html#L391'>remove-between</a> start, end
<span id="L2077" class="LineNr">2077 </span>  <span class="Comment"># update top-of-screen if it's just been invalidated</span>
<span id="L2078" class="LineNr">2078 </span>  <span class="Delimiter">{</span>
<span id="L2079" class="LineNr">2079 </span>    <span class="muControl">break-unless</span> update-top-of-screen?
<span id="L2080" class="LineNr">2080 </span>    put *editor, <span class="Constant">top-of-screen:offset</span>, start
<span id="L2081" class="LineNr">2081 </span>  <span class="Delimiter">}</span>
<span id="L2082" class="LineNr">2082 </span>  <span class="Comment"># adjust cursor</span>
<span id="L2083" class="LineNr">2083 </span>  before-cursor <span class="Special">&lt;-</span> copy start
<span id="L2084" class="LineNr">2084 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L2085" class="LineNr">2085 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L2086" class="LineNr">2086 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, left
<span id="L2087" class="LineNr">2087 </span>  <span class="Comment"># if the line wrapped before, we may need to adjust cursor-row as well</span>
<span id="L2088" class="LineNr">2088 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L2089" class="LineNr">2089 </span>  width:num <span class="Special">&lt;-</span> subtract right, left
<span id="L2090" class="LineNr">2090 </span>  num-deleted:num <span class="Special">&lt;-</span> length result
<span id="L2091" class="LineNr">2091 </span>  cursor-row-adjustment:num <span class="Special">&lt;-</span> divide-with-remainder num-deleted, width
<span id="L2092" class="LineNr">2092 </span>  <span class="muControl">return-unless</span> cursor-row-adjustment
<span id="L2093" class="LineNr">2093 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L2094" class="LineNr">2094 </span>  cursor-row-in-editor:num <span class="Special">&lt;-</span> subtract cursor-row,<span class="Constant"> 1</span>  <span class="Comment"># ignore menubar</span>
<span id="L2095" class="LineNr">2095 </span>  at-top?:bool <span class="Special">&lt;-</span> lesser-or-equal cursor-row-in-editor, cursor-row-adjustment
<span id="L2096" class="LineNr">2096 </span>  <span class="Delimiter">{</span>
<span id="L2097" class="LineNr">2097 </span>    <span class="muControl">break-unless</span> at-top?
<span id="L2098" class="LineNr">2098 </span>    cursor-row <span class="Special">&lt;-</span> copy<span class="Constant"> 1</span>  <span class="Comment"># top of editor, below menubar</span>
<span id="L2099" class="LineNr">2099 </span>  <span class="Delimiter">}</span>
<span id="L2100" class="LineNr">2100 </span>  <span class="Delimiter">{</span>
<span id="L2101" class="LineNr">2101 </span>    <span class="muControl">break-if</span> at-top?
<span id="L2102" class="LineNr">2102 </span>    cursor-row <span class="Special">&lt;-</span> subtract cursor-row, cursor-row-adjustment
<span id="L2103" class="LineNr">2103 </span>  <span class="Delimiter">}</span>
<span id="L2104" class="LineNr">2104 </span>  put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
<span id="L2105" class="LineNr">2105 </span>]
<span id="L2106" class="LineNr">2106 </span>
<span id="L2107" class="LineNr">2107 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L2107'>render-code</a> <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a>, s:text, left:num, right:num, row:num<span class="muRecipe"> -&gt; </span>row:num, <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a> [
<span id="L2108" class="LineNr">2108 </span>  <span class="Constant">local-scope</span>
<span id="L2109" class="LineNr">2109 </span>  <span class="Constant">load-inputs</span>
<span id="L2110" class="LineNr">2110 </span>  <span class="muControl">return-unless</span> s
<span id="L2111" class="LineNr">2111 </span>  color:num <span class="Special">&lt;-</span> copy <span class="Constant">7/white</span>
<span id="L2112" class="LineNr">2112 </span>  column:num <span class="Special">&lt;-</span> copy left
<span id="L2113" class="LineNr">2113 </span>  <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> move-cursor <a href='../081print.mu.html#L16'>screen</a>, row, column
<span id="L2114" class="LineNr">2114 </span>  <a href='../081print.mu.html#L782'>screen-height</a>:num <span class="Special">&lt;-</span> <a href='../081print.mu.html#L782'>screen-height</a> <a href='../081print.mu.html#L16'>screen</a>
<span id="L2115" class="LineNr">2115 </span>  i:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
<span id="L2116" class="LineNr">2116 </span>  len:num <span class="Special">&lt;-</span> length *s
<span id="L2117" class="LineNr">2117 </span>  <span class="Delimiter">{</span>
<span id="L2118" class="LineNr">2118 </span><span class="Constant">    +next-character</span>
<span id="L2119" class="LineNr">2119 </span>    done?:bool <span class="Special">&lt;-</span> greater-or-equal i, len
<span id="L2120" class="LineNr">2120 </span>    <span class="muControl">break-if</span> done?
<span id="L2121" class="LineNr">2121 </span>    done? <span class="Special">&lt;-</span> greater-or-equal row, <a href='../081print.mu.html#L782'>screen-height</a>
<span id="L2122" class="LineNr">2122 </span>    <span class="muControl">break-if</span> done?
<span id="L2123" class="LineNr">2123 </span>    c:char <span class="Special">&lt;-</span> index *s, i
<span id="L2124" class="LineNr">2124 </span><span class="Constant">    &lt;character-c-received&gt;</span>
<span id="L2125" class="LineNr">2125 </span>    <span class="Delimiter">{</span>
<span id="L2126" class="LineNr">2126 </span>      <span class="Comment"># newline? move to left rather than 0</span>
<span id="L2127" class="LineNr">2127 </span>      newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
<span id="L2128" class="LineNr">2128 </span>      <span class="muControl">break-unless</span> newline?
<span id="L2129" class="LineNr">2129 </span>      <span class="Comment"># clear rest of line in this window</span>
<span id="L2130" class="LineNr">2130 </span>      <span class="Delimiter">{</span>
<span id="L2131" class="LineNr">2131 </span>        done?:bool <span class="Special">&lt;-</span> greater-than column, right
<span id="L2132" class="LineNr">2132 </span>        <span class="muControl">break-if</span> done?
<span id="L2133" class="LineNr">2133 </span>        space:char <span class="Special">&lt;-</span> copy <span class="Constant">32/space</span>
<span id="L2134" class="LineNr">2134 </span>        print <a href='../081print.mu.html#L16'>screen</a>, space
<span id="L2135" class="LineNr">2135 </span>        column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
<span id="L2136" class="LineNr">2136 </span>       <span class="muControl"> loop</span>
<span id="L2137" class="LineNr">2137 </span>      <span class="Delimiter">}</span>
<span id="L2138" class="LineNr">2138 </span>      row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
<span id="L2139" class="LineNr">2139 </span>      column <span class="Special">&lt;-</span> copy left
<span id="L2140" class="LineNr">2140 </span>      <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> move-cursor <a href='../081print.mu.html#L16'>screen</a>, row, column
<span id="L2141" class="LineNr">2141 </span>      i <span class="Special">&lt;-</span> add i,<span class="Constant"> 1</span>
<span id="L2142" class="LineNr">2142 </span>     <span class="muControl"> loop</span> <span class="Constant">+next-character</span>
<span id="L2143" class="LineNr">2143 </span>    <span class="Delimiter">}</span>
<span id="L2144" class="LineNr">2144 </span>    <span class="Delimiter">{</span>
<span id="L2145" class="LineNr">2145 </span>      <span class="Comment"># at right? wrap.</span>
<span id="L2146" class="LineNr">2146 </span>      at-right?:bool <span class="Special">&lt;-</span> equal column, right
<span id="L2147" class="LineNr">2147 </span>      <span class="muControl">break-unless</span> at-right?
<span id="L2148" class="LineNr">2148 </span>      <span class="Comment"># print wrap icon</span>
<span id="L2149" class="LineNr">2149 </span>      wrap-icon:char <span class="Special">&lt;-</span> copy <span class="Constant">8617/loop-back-to-left</span>
<span id="L2150" class="LineNr">2150 </span>      print <a href='../081print.mu.html#L16'>screen</a>, wrap-icon, <span class="Constant">245/grey</span>
<span id="L2151" class="LineNr">2151 </span>      column <span class="Special">&lt;-</span> copy left
<span id="L2152" class="LineNr">2152 </span>      row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
<span id="L2153" class="LineNr">2153 </span>      <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> move-cursor <a href='../081print.mu.html#L16'>screen</a>, row, column
<span id="L2154" class="LineNr">2154 </span>      <span class="Comment"># don't increment i</span>
<span id="L2155" class="LineNr">2155 </span>     <span class="muControl"> loop</span> <span class="Constant">+next-character</span>
<span id="L2156" class="LineNr">2156 </span>    <span class="Delimiter">}</span>
<span id="L2157" class="LineNr">2157 </span>    i <span class="Special">&lt;-</span> add i,<span class="Constant"> 1</span>
<span id="L2158" class="LineNr">2158 </span>    print <a href='../081print.mu.html#L16'>screen</a>, c, color
<span id="L2159" class="LineNr">2159 </span>    column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
<span id="L2160" class="LineNr">2160 </span>   <span class="muControl"> loop</span>
<span id="L2161" class="LineNr">2161 </span>  <span class="Delimiter">}</span>
<span id="L2162" class="LineNr">2162 </span>  was-at-left?:bool <span class="Special">&lt;-</span> equal column, left
<span id="L2163" class="LineNr">2163 </span>  <a href='../081print.mu.html#L553'>clear-line-until</a> <a href='../081print.mu.html#L16'>screen</a>, right
<span id="L2164" class="LineNr">2164 </span>  <span class="Delimiter">{</span>
<span id="L2165" class="LineNr">2165 </span>    <span class="muControl">break-if</span> was-at-left?
<span id="L2166" class="LineNr">2166 </span>    row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
<span id="L2167" class="LineNr">2167 </span>  <span class="Delimiter">}</span>
<span id="L2168" class="LineNr">2168 </span>  move-cursor <a href='../081print.mu.html#L16'>screen</a>, row, left
<span id="L2169" class="LineNr">2169 </span>]
<span id="L2170" class="LineNr">2170 </span>
<span id="L2171" class="LineNr">2171 </span><span class="muScenario">scenario</span> editor-deletes-to-start-of-line-with-ctrl-u-2 [
<span id="L2172" class="LineNr">2172 </span>  <span class="Constant">local-scope</span>
<span id="L2173" class="LineNr">2173 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L2174" class="LineNr">2174 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L2175" class="LineNr">2175 </span><span class="Constant">456]</span>
<span id="L2176" class="LineNr">2176 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L2177" class="LineNr">2177 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2178" class="LineNr">2178 </span>  $clear-trace
<span id="L2179" class="LineNr">2179 </span>  <span class="Comment"># start on first line (no newline before), press ctrl-u</span>
<span id="L2180" class="LineNr">2180 </span>  assume-console [
<span id="L2181" class="LineNr">2181 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 2</span>
<span id="L2182" class="LineNr">2182 </span>    press ctrl-u
<span id="L2183" class="LineNr">2183 </span>  ]
<span id="L2184" class="LineNr">2184 </span>  run [
<span id="L2185" class="LineNr">2185 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2186" class="LineNr">2186 </span>  ]
<span id="L2187" class="LineNr">2187 </span>  <span class="Comment"># cursor deletes to start of line</span>
<span id="L2188" class="LineNr">2188 </span>  screen-should-contain [
<span id="L2189" class="LineNr">2189 </span>   <span class="Constant"> .          .</span>
<span id="L2190" class="LineNr">2190 </span>   <span class="Constant"> .3         .</span>
<span id="L2191" class="LineNr">2191 </span>   <span class="Constant"> .456       .</span>
<span id="L2192" class="LineNr">2192 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2193" class="LineNr">2193 </span>   <span class="Constant"> .          .</span>
<span id="L2194" class="LineNr">2194 </span>  ]
<span id="L2195" class="LineNr">2195 </span>  check-trace-count-for-label<span class="Constant"> 10</span>, <span class="Constant">[print-character]</span>
<span id="L2196" class="LineNr">2196 </span>]
<span id="L2197" class="LineNr">2197 </span>
<span id="L2198" class="LineNr">2198 </span><span class="muScenario">scenario</span> editor-deletes-to-start-of-line-with-ctrl-u-3 [
<span id="L2199" class="LineNr">2199 </span>  <span class="Constant">local-scope</span>
<span id="L2200" class="LineNr">2200 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L2201" class="LineNr">2201 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L2202" class="LineNr">2202 </span><span class="Constant">456]</span>
<span id="L2203" class="LineNr">2203 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L2204" class="LineNr">2204 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2205" class="LineNr">2205 </span>  $clear-trace
<span id="L2206" class="LineNr">2206 </span>  <span class="Comment"># start past end of line, press ctrl-u</span>
<span id="L2207" class="LineNr">2207 </span>  assume-console [
<span id="L2208" class="LineNr">2208 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
<span id="L2209" class="LineNr">2209 </span>    press ctrl-u
<span id="L2210" class="LineNr">2210 </span>  ]
<span id="L2211" class="LineNr">2211 </span>  run [
<span id="L2212" class="LineNr">2212 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2213" class="LineNr">2213 </span>  ]
<span id="L2214" class="LineNr">2214 </span>  <span class="Comment"># cursor deletes to start of line</span>
<span id="L2215" class="LineNr">2215 </span>  screen-should-contain [
<span id="L2216" class="LineNr">2216 </span>   <span class="Constant"> .          .</span>
<span id="L2217" class="LineNr">2217 </span>   <span class="Constant"> .          .</span>
<span id="L2218" class="LineNr">2218 </span>   <span class="Constant"> .456       .</span>
<span id="L2219" class="LineNr">2219 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2220" class="LineNr">2220 </span>   <span class="Constant"> .          .</span>
<span id="L2221" class="LineNr">2221 </span>  ]
<span id="L2222" class="LineNr">2222 </span>  check-trace-count-for-label<span class="Constant"> 10</span>, <span class="Constant">[print-character]</span>
<span id="L2223" class="LineNr">2223 </span>]
<span id="L2224" class="LineNr">2224 </span>
<span id="L2225" class="LineNr">2225 </span><span class="muScenario">scenario</span> editor-deletes-to-start-of-final-line-with-ctrl-u [
<span id="L2226" class="LineNr">2226 </span>  <span class="Constant">local-scope</span>
<span id="L2227" class="LineNr">2227 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L2228" class="LineNr">2228 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L2229" class="LineNr">2229 </span><span class="Constant">456]</span>
<span id="L2230" class="LineNr">2230 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L2231" class="LineNr">2231 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2232" class="LineNr">2232 </span>  $clear-trace
<span id="L2233" class="LineNr">2233 </span>  <span class="Comment"># start past end of final line, press ctrl-u</span>
<span id="L2234" class="LineNr">2234 </span>  assume-console [
<span id="L2235" class="LineNr">2235 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
<span id="L2236" class="LineNr">2236 </span>    press ctrl-u
<span id="L2237" class="LineNr">2237 </span>  ]
<span id="L2238" class="LineNr">2238 </span>  run [
<span id="L2239" class="LineNr">2239 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2240" class="LineNr">2240 </span>  ]
<span id="L2241" class="LineNr">2241 </span>  <span class="Comment"># cursor deletes to start of line</span>
<span id="L2242" class="LineNr">2242 </span>  screen-should-contain [
<span id="L2243" class="LineNr">2243 </span>   <span class="Constant"> .          .</span>
<span id="L2244" class="LineNr">2244 </span>   <span class="Constant"> .123       .</span>
<span id="L2245" class="LineNr">2245 </span>   <span class="Constant"> .          .</span>
<span id="L2246" class="LineNr">2246 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2247" class="LineNr">2247 </span>   <span class="Constant"> .          .</span>
<span id="L2248" class="LineNr">2248 </span>  ]
<span id="L2249" class="LineNr">2249 </span>  check-trace-count-for-label<span class="Constant"> 10</span>, <span class="Constant">[print-character]</span>
<span id="L2250" class="LineNr">2250 </span>]
<span id="L2251" class="LineNr">2251 </span>
<span id="L2252" class="LineNr">2252 </span><span class="muScenario">scenario</span> editor-deletes-to-start-of-wrapped-line-with-ctrl-u [
<span id="L2253" class="LineNr">2253 </span>  <span class="Constant">local-scope</span>
<span id="L2254" class="LineNr">2254 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">10/height</span>
<span id="L2255" class="LineNr">2255 </span>  <span class="Comment"># first line starts out wrapping</span>
<span id="L2256" class="LineNr">2256 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123456</span>
<span id="L2257" class="LineNr">2257 </span><span class="Constant">789]</span>
<span id="L2258" class="LineNr">2258 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L2259" class="LineNr">2259 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2260" class="LineNr">2260 </span>  screen-should-contain [
<span id="L2261" class="LineNr">2261 </span>   <span class="Constant"> .          .</span>
<span id="L2262" class="LineNr">2262 </span>   <span class="Constant"> .1234↩     .</span>
<span id="L2263" class="LineNr">2263 </span>   <span class="Constant"> .56        .</span>
<span id="L2264" class="LineNr">2264 </span>   <span class="Constant"> .789       .</span>
<span id="L2265" class="LineNr">2265 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2266" class="LineNr">2266 </span>   <span class="Constant"> .          .</span>
<span id="L2267" class="LineNr">2267 </span>  ]
<span id="L2268" class="LineNr">2268 </span>  $clear-trace
<span id="L2269" class="LineNr">2269 </span>  <span class="Comment"># ctrl-u enough of the first line that it's no longer wrapping</span>
<span id="L2270" class="LineNr">2270 </span>  assume-console [
<span id="L2271" class="LineNr">2271 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
<span id="L2272" class="LineNr">2272 </span>    press ctrl-u
<span id="L2273" class="LineNr">2273 </span>  ]
<span id="L2274" class="LineNr">2274 </span>  run [
<span id="L2275" class="LineNr">2275 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2276" class="LineNr">2276 </span>  ]
<span id="L2277" class="LineNr">2277 </span>  <span class="Comment"># entire screen needs to be refreshed</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"> .456       .</span>
<span id="L2281" class="LineNr">2281 </span>   <span class="Constant"> .789       .</span>
<span id="L2282" class="LineNr">2282 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2283" class="LineNr">2283 </span>   <span class="Constant"> .          .</span>
<span id="L2284" class="LineNr">2284 </span>  ]
<span id="L2285" class="LineNr">2285 </span>  check-trace-count-for-label<span class="Constant"> 45</span>, <span class="Constant">[print-character]</span>
<span id="L2286" class="LineNr">2286 </span>]
<span id="L2287" class="LineNr">2287 </span>
<span id="L2288" class="LineNr">2288 </span><span class="Comment"># sometimes hitting ctrl-u needs to adjust the cursor row</span>
<span id="L2289" class="LineNr">2289 </span><span class="muScenario">scenario</span> editor-deletes-to-start-of-wrapped-line-with-ctrl-u-2 [
<span id="L2290" class="LineNr">2290 </span>  <span class="Constant">local-scope</span>
<span id="L2291" class="LineNr">2291 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">10/height</span>
<span id="L2292" class="LineNr">2292 </span>  <span class="Comment"># third line starts out wrapping</span>
<span id="L2293" class="LineNr">2293 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[1</span>
<span id="L2294" class="LineNr">2294 </span><span class="Constant">2</span>
<span id="L2295" class="LineNr">2295 </span><span class="Constant">345678</span>
<span id="L2296" class="LineNr">2296 </span><span class="Constant">9]</span>
<span id="L2297" class="LineNr">2297 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L2298" class="LineNr">2298 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2299" class="LineNr">2299 </span>  screen-should-contain [
<span id="L2300" class="LineNr">2300 </span>   <span class="Constant"> .          .</span>
<span id="L2301" class="LineNr">2301 </span>   <span class="Constant"> .1         .</span>
<span id="L2302" class="LineNr">2302 </span>   <span class="Constant"> .2         .</span>
<span id="L2303" class="LineNr">2303 </span>   <span class="Constant"> .3456↩     .</span>
<span id="L2304" class="LineNr">2304 </span>   <span class="Constant"> .78        .</span>
<span id="L2305" class="LineNr">2305 </span>   <span class="Constant"> .9         .</span>
<span id="L2306" class="LineNr">2306 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2307" class="LineNr">2307 </span>   <span class="Constant"> .          .</span>
<span id="L2308" class="LineNr">2308 </span>  ]
<span id="L2309" class="LineNr">2309 </span>  <span class="Comment"># position cursor on screen line after the wrap and hit ctrl-u</span>
<span id="L2310" class="LineNr">2310 </span>  assume-console [
<span id="L2311" class="LineNr">2311 </span>    left-click<span class="Constant"> 4</span>,<span class="Constant"> 1</span>  <span class="Comment"># on '8'</span>
<span id="L2312" class="LineNr">2312 </span>    press ctrl-u
<span id="L2313" class="LineNr">2313 </span>  ]
<span id="L2314" class="LineNr">2314 </span>  run [
<span id="L2315" class="LineNr">2315 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2316" class="LineNr">2316 </span>    10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L2317" class="LineNr">2317 </span>    11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L2318" class="LineNr">2318 </span>  ]
<span id="L2319" class="LineNr">2319 </span>  screen-should-contain [
<span id="L2320" class="LineNr">2320 </span>   <span class="Constant"> .          .</span>
<span id="L2321" class="LineNr">2321 </span>   <span class="Constant"> .1         .</span>
<span id="L2322" class="LineNr">2322 </span>   <span class="Constant"> .2         .</span>
<span id="L2323" class="LineNr">2323 </span>   <span class="Constant"> .8         .</span>
<span id="L2324" class="LineNr">2324 </span>   <span class="Constant"> .9         .</span>
<span id="L2325" class="LineNr">2325 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2326" class="LineNr">2326 </span>   <span class="Constant"> .          .</span>
<span id="L2327" class="LineNr">2327 </span>  ]
<span id="L2328" class="LineNr">2328 </span>  <span class="Comment"># cursor moves up one screen line</span>
<span id="L2329" class="LineNr">2329 </span>  memory-should-contain [
<span id="L2330" class="LineNr">2330 </span>   <span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>  <span class="Comment"># cursor-row</span>
<span id="L2331" class="LineNr">2331 </span>   <span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># cursor-column</span>
<span id="L2332" class="LineNr">2332 </span>  ]
<span id="L2333" class="LineNr">2333 </span>]
<span id="L2334" class="LineNr">2334 </span>
<span id="L2335" class="LineNr">2335 </span><span class="Comment"># line wrapping twice (taking up 3 screen lines)</span>
<span id="L2336" class="LineNr">2336 </span><span class="muScenario">scenario</span> editor-deletes-to-start-of-wrapped-line-with-ctrl-u-3 [
<span id="L2337" class="LineNr">2337 </span>  <span class="Constant">local-scope</span>
<span id="L2338" class="LineNr">2338 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">10/height</span>
<span id="L2339" class="LineNr">2339 </span>  <span class="Comment"># third line starts out wrapping</span>
<span id="L2340" class="LineNr">2340 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[1</span>
<span id="L2341" class="LineNr">2341 </span><span class="Constant">2</span>
<span id="L2342" class="LineNr">2342 </span><span class="Constant">3456789abcd</span>
<span id="L2343" class="LineNr">2343 </span><span class="Constant">e]</span>
<span id="L2344" class="LineNr">2344 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L2345" class="LineNr">2345 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2346" class="LineNr">2346 </span>  assume-console [
<span id="L2347" class="LineNr">2347 </span>    left-click<span class="Constant"> 4</span>,<span class="Constant"> 1</span>  <span class="Comment"># on '8'</span>
<span id="L2348" class="LineNr">2348 </span>  ]
<span id="L2349" class="LineNr">2349 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2350" class="LineNr">2350 </span>  screen-should-contain [
<span id="L2351" class="LineNr">2351 </span>   <span class="Constant"> .          .</span>
<span id="L2352" class="LineNr">2352 </span>   <span class="Constant"> .1         .</span>
<span id="L2353" class="LineNr">2353 </span>   <span class="Constant"> .2         .</span>
<span id="L2354" class="LineNr">2354 </span>   <span class="Constant"> .3456↩     .</span>
<span id="L2355" class="LineNr">2355 </span>   <span class="Constant"> .789a↩     .</span>
<span id="L2356" class="LineNr">2356 </span>   <span class="Constant"> .bcd       .</span>
<span id="L2357" class="LineNr">2357 </span>   <span class="Constant"> .e         .</span>
<span id="L2358" class="LineNr">2358 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2359" class="LineNr">2359 </span>   <span class="Constant"> .          .</span>
<span id="L2360" class="LineNr">2360 </span>  ]
<span id="L2361" class="LineNr">2361 </span>  assume-console [
<span id="L2362" class="LineNr">2362 </span>    left-click<span class="Constant"> 5</span>,<span class="Constant"> 1</span>
<span id="L2363" class="LineNr">2363 </span>    press ctrl-u
<span id="L2364" class="LineNr">2364 </span>  ]
<span id="L2365" class="LineNr">2365 </span>  run [
<span id="L2366" class="LineNr">2366 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2367" class="LineNr">2367 </span>    10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L2368" class="LineNr">2368 </span>    11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L2369" class="LineNr">2369 </span>  ]
<span id="L2370" class="LineNr">2370 </span>  screen-should-contain [
<span id="L2371" class="LineNr">2371 </span>   <span class="Constant"> .          .</span>
<span id="L2372" class="LineNr">2372 </span>   <span class="Constant"> .1         .</span>
<span id="L2373" class="LineNr">2373 </span>   <span class="Constant"> .2         .</span>
<span id="L2374" class="LineNr">2374 </span>   <span class="Constant"> .cd        .</span>
<span id="L2375" class="LineNr">2375 </span>   <span class="Constant"> .e         .</span>
<span id="L2376" class="LineNr">2376 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2377" class="LineNr">2377 </span>   <span class="Constant"> .          .</span>
<span id="L2378" class="LineNr">2378 </span>  ]
<span id="L2379" class="LineNr">2379 </span>  <span class="Comment"># make sure we adjusted cursor-row</span>
<span id="L2380" class="LineNr">2380 </span>  memory-should-contain [
<span id="L2381" class="LineNr">2381 </span>   <span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>  <span class="Comment"># cursor-row</span>
<span id="L2382" class="LineNr">2382 </span>   <span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># cursor-column</span>
<span id="L2383" class="LineNr">2383 </span>  ]
<span id="L2384" class="LineNr">2384 </span>]
<span id="L2385" class="LineNr">2385 </span>
<span id="L2386" class="LineNr">2386 </span><span class="Comment"># adjusting cursor row at the top of the screen</span>
<span id="L2387" class="LineNr">2387 </span><span class="muScenario">scenario</span> editor-deletes-to-start-of-wrapped-line-with-ctrl-u-4 [
<span id="L2388" class="LineNr">2388 </span>  <span class="Constant">local-scope</span>
<span id="L2389" class="LineNr">2389 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">10/height</span>
<span id="L2390" class="LineNr">2390 </span>  <span class="Comment"># first line starts out wrapping</span>
<span id="L2391" class="LineNr">2391 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[1234567</span>
<span id="L2392" class="LineNr">2392 </span><span class="Constant">89]</span>
<span id="L2393" class="LineNr">2393 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L2394" class="LineNr">2394 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2395" class="LineNr">2395 </span>  screen-should-contain [
<span id="L2396" class="LineNr">2396 </span>   <span class="Constant"> .          .</span>
<span id="L2397" class="LineNr">2397 </span>   <span class="Constant"> .1234↩     .</span>
<span id="L2398" class="LineNr">2398 </span>   <span class="Constant"> .567       .</span>
<span id="L2399" class="LineNr">2399 </span>   <span class="Constant"> .89        .</span>
<span id="L2400" class="LineNr">2400 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2401" class="LineNr">2401 </span>   <span class="Constant"> .          .</span>
<span id="L2402" class="LineNr">2402 </span>  ]
<span id="L2403" class="LineNr">2403 </span>  <span class="Comment"># position cursor on second screen line (after the wrap) and hit ctrl-u</span>
<span id="L2404" class="LineNr">2404 </span>  assume-console [
<span id="L2405" class="LineNr">2405 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
<span id="L2406" class="LineNr">2406 </span>    press ctrl-u
<span id="L2407" class="LineNr">2407 </span>  ]
<span id="L2408" class="LineNr">2408 </span>  run [
<span id="L2409" class="LineNr">2409 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2410" class="LineNr">2410 </span>    10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L2411" class="LineNr">2411 </span>    11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L2412" class="LineNr">2412 </span>  ]
<span id="L2413" class="LineNr">2413 </span>  screen-should-contain [
<span id="L2414" class="LineNr">2414 </span>   <span class="Constant"> .          .</span>
<span id="L2415" class="LineNr">2415 </span>   <span class="Constant"> .67        .</span>
<span id="L2416" class="LineNr">2416 </span>   <span class="Constant"> .89        .</span>
<span id="L2417" class="LineNr">2417 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2418" class="LineNr">2418 </span>   <span class="Constant"> .          .</span>
<span id="L2419" class="LineNr">2419 </span>  ]
<span id="L2420" class="LineNr">2420 </span>  <span class="Comment"># cursor moves up to screen line 1</span>
<span id="L2421" class="LineNr">2421 </span>  memory-should-contain [
<span id="L2422" class="LineNr">2422 </span>   <span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># cursor-row</span>
<span id="L2423" class="LineNr">2423 </span>   <span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># cursor-column</span>
<span id="L2424" class="LineNr">2424 </span>  ]
<span id="L2425" class="LineNr">2425 </span>]
<span id="L2426" class="LineNr">2426 </span>
<span id="L2427" class="LineNr">2427 </span><span class="Comment"># screen begins part-way through a wrapping line</span>
<span id="L2428" class="LineNr">2428 </span><span class="muScenario">scenario</span> editor-deletes-to-start-of-wrapped-line-with-ctrl-u-5 [
<span id="L2429" class="LineNr">2429 </span>  <span class="Constant">local-scope</span>
<span id="L2430" class="LineNr">2430 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">10/height</span>
<span id="L2431" class="LineNr">2431 </span>  <span class="Comment"># third line starts out wrapping</span>
<span id="L2432" class="LineNr">2432 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[1</span>
<span id="L2433" class="LineNr">2433 </span><span class="Constant">2</span>
<span id="L2434" class="LineNr">2434 </span><span class="Constant">345678</span>
<span id="L2435" class="LineNr">2435 </span><span class="Constant">9]</span>
<span id="L2436" class="LineNr">2436 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L2437" class="LineNr">2437 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2438" class="LineNr">2438 </span>  <span class="Comment"># position the '78' line at the top of the screen</span>
<span id="L2439" class="LineNr">2439 </span>  assume-console [
<span id="L2440" class="LineNr">2440 </span>    left-click<span class="Constant"> 4</span>,<span class="Constant"> 1</span>  <span class="Comment"># on '8'</span>
<span id="L2441" class="LineNr">2441 </span>    press ctrl-t
<span id="L2442" class="LineNr">2442 </span>  ]
<span id="L2443" class="LineNr">2443 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2444" class="LineNr">2444 </span>  screen-should-contain [
<span id="L2445" class="LineNr">2445 </span>   <span class="Constant"> .          .</span>
<span id="L2446" class="LineNr">2446 </span>   <span class="Constant"> .78        .</span>
<span id="L2447" class="LineNr">2447 </span>   <span class="Constant"> .9         .</span>
<span id="L2448" class="LineNr">2448 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2449" class="LineNr">2449 </span>   <span class="Constant"> .          .</span>
<span id="L2450" class="LineNr">2450 </span>  ]
<span id="L2451" class="LineNr">2451 </span>  assume-console [
<span id="L2452" class="LineNr">2452 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
<span id="L2453" class="LineNr">2453 </span>    press ctrl-u
<span id="L2454" class="LineNr">2454 </span>  ]
<span id="L2455" class="LineNr">2455 </span>  run [
<span id="L2456" class="LineNr">2456 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2457" class="LineNr">2457 </span>    10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L2458" class="LineNr">2458 </span>    11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L2459" class="LineNr">2459 </span>  ]
<span id="L2460" class="LineNr">2460 </span>  <span class="Comment"># make sure we updated top-of-screen correctly</span>
<span id="L2461" class="LineNr">2461 </span>  screen-should-contain [
<span id="L2462" class="LineNr">2462 </span>   <span class="Constant"> .          .</span>
<span id="L2463" class="LineNr">2463 </span>   <span class="Constant"> .8         .</span>
<span id="L2464" class="LineNr">2464 </span>   <span class="Constant"> .9         .</span>
<span id="L2465" class="LineNr">2465 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2466" class="LineNr">2466 </span>   <span class="Constant"> .          .</span>
<span id="L2467" class="LineNr">2467 </span>  ]
<span id="L2468" class="LineNr">2468 </span>  memory-should-contain [
<span id="L2469" class="LineNr">2469 </span>   <span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># cursor-row</span>
<span id="L2470" class="LineNr">2470 </span>   <span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># cursor-column</span>
<span id="L2471" class="LineNr">2471 </span>  ]
<span id="L2472" class="LineNr">2472 </span>  <span class="Comment"># the entire line is deleted, even the part not shown on screen</span>
<span id="L2473" class="LineNr">2473 </span>  assume-console [
<span id="L2474" class="LineNr">2474 </span>    press up-arrow
<span id="L2475" class="LineNr">2475 </span>  ]
<span id="L2476" class="LineNr">2476 </span>  run [
<span id="L2477" class="LineNr">2477 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2478" class="LineNr">2478 </span>  ]
<span id="L2479" class="LineNr">2479 </span>  screen-should-contain [
<span id="L2480" class="LineNr">2480 </span>   <span class="Constant"> .          .</span>
<span id="L2481" class="LineNr">2481 </span>   <span class="Constant"> .2         .</span>
<span id="L2482" class="LineNr">2482 </span>   <span class="Constant"> .8         .</span>
<span id="L2483" class="LineNr">2483 </span>   <span class="Constant"> .9         .</span>
<span id="L2484" class="LineNr">2484 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2485" class="LineNr">2485 </span>   <span class="Constant"> .          .</span>
<span id="L2486" class="LineNr">2486 </span>  ]
<span id="L2487" class="LineNr">2487 </span>]
<span id="L2488" class="LineNr">2488 </span>
<span id="L2489" class="LineNr">2489 </span><span class="Comment"># screen begins part-way through a line wrapping twice (taking up 3 screen lines)</span>
<span id="L2490" class="LineNr">2490 </span><span class="muScenario">scenario</span> editor-deletes-to-start-of-wrapped-line-with-ctrl-u-6 [
<span id="L2491" class="LineNr">2491 </span>  <span class="Constant">local-scope</span>
<span id="L2492" class="LineNr">2492 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">10/height</span>
<span id="L2493" class="LineNr">2493 </span>  <span class="Comment"># third line starts out wrapping</span>
<span id="L2494" class="LineNr">2494 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[1</span>
<span id="L2495" class="LineNr">2495 </span><span class="Constant">2</span>
<span id="L2496" class="LineNr">2496 </span><span class="Constant">3456789abcd</span>
<span id="L2497" class="LineNr">2497 </span><span class="Constant">e]</span>
<span id="L2498" class="LineNr">2498 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L2499" class="LineNr">2499 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2500" class="LineNr">2500 </span>  <span class="Comment"># position the 'bcd' line at the top of the screen</span>
<span id="L2501" class="LineNr">2501 </span>  assume-console [
<span id="L2502" class="LineNr">2502 </span>    left-click<span class="Constant"> 4</span>,<span class="Constant"> 1</span>  <span class="Comment"># on '8'</span>
<span id="L2503" class="LineNr">2503 </span>    press ctrl-t
<span id="L2504" class="LineNr">2504 </span>    press ctrl-s  <span class="Comment"># now on 'c'</span>
<span id="L2505" class="LineNr">2505 </span>  ]
<span id="L2506" class="LineNr">2506 </span>  <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2507" class="LineNr">2507 </span>  screen-should-contain [
<span id="L2508" class="LineNr">2508 </span>   <span class="Constant"> .          .</span>
<span id="L2509" class="LineNr">2509 </span>   <span class="Constant"> .bcd       .</span>
<span id="L2510" class="LineNr">2510 </span>   <span class="Constant"> .e         .</span>
<span id="L2511" class="LineNr">2511 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2512" class="LineNr">2512 </span>   <span class="Constant"> .          .</span>
<span id="L2513" class="LineNr">2513 </span>  ]
<span id="L2514" class="LineNr">2514 </span>  assume-console [
<span id="L2515" class="LineNr">2515 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
<span id="L2516" class="LineNr">2516 </span>    press ctrl-u
<span id="L2517" class="LineNr">2517 </span>  ]
<span id="L2518" class="LineNr">2518 </span>  run [
<span id="L2519" class="LineNr">2519 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2520" class="LineNr">2520 </span>    10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L2521" class="LineNr">2521 </span>    11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L2522" class="LineNr">2522 </span>  ]
<span id="L2523" class="LineNr">2523 </span>  <span class="Comment"># make sure we updated top-of-screen correctly</span>
<span id="L2524" class="LineNr">2524 </span>  screen-should-contain [
<span id="L2525" class="LineNr">2525 </span>   <span class="Constant"> .          .</span>
<span id="L2526" class="LineNr">2526 </span>   <span class="Constant"> .cd        .</span>
<span id="L2527" class="LineNr">2527 </span>   <span class="Constant"> .e         .</span>
<span id="L2528" class="LineNr">2528 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2529" class="LineNr">2529 </span>   <span class="Constant"> .          .</span>
<span id="L2530" class="LineNr">2530 </span>  ]
<span id="L2531" class="LineNr">2531 </span>  memory-should-contain [
<span id="L2532" class="LineNr">2532 </span>   <span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># cursor-row</span>
<span id="L2533" class="LineNr">2533 </span>   <span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># cursor-column</span>
<span id="L2534" class="LineNr">2534 </span>  ]
<span id="L2535" class="LineNr">2535 </span>  <span class="Comment"># the entire line is deleted, even the part not shown on screen</span>
<span id="L2536" class="LineNr">2536 </span>  assume-console [
<span id="L2537" class="LineNr">2537 </span>    press up-arrow
<span id="L2538" class="LineNr">2538 </span>  ]
<span id="L2539" class="LineNr">2539 </span>  run [
<span id="L2540" class="LineNr">2540 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2541" class="LineNr">2541 </span>  ]
<span id="L2542" class="LineNr">2542 </span>  screen-should-contain [
<span id="L2543" class="LineNr">2543 </span>   <span class="Constant"> .          .</span>
<span id="L2544" class="LineNr">2544 </span>   <span class="Constant"> .2         .</span>
<span id="L2545" class="LineNr">2545 </span>   <span class="Constant"> .cd        .</span>
<span id="L2546" class="LineNr">2546 </span>   <span class="Constant"> .e         .</span>
<span id="L2547" class="LineNr">2547 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L2548" class="LineNr">2548 </span>   <span class="Constant"> .          .</span>
<span id="L2549" class="LineNr">2549 </span>  ]
<span id="L2550" class="LineNr">2550 </span>]
<span id="L2551" class="LineNr">2551 </span>
<span id="L2552" class="LineNr">2552 </span><span class="Comment"># ctrl-k - delete text from cursor to end of line (but not the newline)</span>
<span id="L2553" class="LineNr">2553 </span>
<span id="L2554" class="LineNr">2554 </span><span class="muScenario">scenario</span> editor-deletes-to-end-of-line-with-ctrl-k [
<span id="L2555" class="LineNr">2555 </span>  <span class="Constant">local-scope</span>
<span id="L2556" class="LineNr">2556 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L2557" class="LineNr">2557 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L2558" class="LineNr">2558 </span><span class="Constant">456]</span>
<span id="L2559" class="LineNr">2559 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L2560" class="LineNr">2560 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2561" class="LineNr">2561 </span>  $clear-trace
<span id="L2562" class="LineNr">2562 </span>  <span class="Comment"># start on first line, press ctrl-k</span>
<span id="L2563" class="LineNr">2563 </span>  assume-console [
<span id="L2564" class="LineNr">2564 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 1</span>
<span id="L2565" class="LineNr">2565 </span>    press ctrl-k
<span id="L2566" class="LineNr">2566 </span>  ]
<span id="L2567" class="LineNr">2567 </span>  run [
<span id="L2568" class="LineNr">2568 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2569" class="LineNr">2569 </span>  ]
<span id="L2570" class="LineNr">2570 </span>  <span class="Comment"># cursor deletes to end of line</span>
<span id="L2571" class="LineNr">2571 </span>  screen-should-contain [
<span id="L2572" class="LineNr">2572 </span>   <span class="Constant"> .          .</span>
<span id="L2573" class="LineNr">2573 </span>   <span class="Constant"> .1         .</span>
<span id="L2574" class="LineNr">2574 </span>   <span class="Constant"> .456       .</span>
<span id="L2575" class="LineNr">2575 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2576" class="LineNr">2576 </span>   <span class="Constant"> .          .</span>
<span id="L2577" class="LineNr">2577 </span>  ]
<span id="L2578" class="LineNr">2578 </span>  check-trace-count-for-label<span class="Constant"> 9</span>, <span class="Constant">[print-character]</span>
<span id="L2579" class="LineNr">2579 </span>]
<span id="L2580" class="LineNr">2580 </span>
<span id="L2581" class="LineNr">2581 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L2582" class="LineNr">2582 </span>  <span class="Delimiter">{</span>
<span id="L2583" class="LineNr">2583 </span>    delete-to-end-of-line?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">11/ctrl-k</span>
<span id="L2584" class="LineNr">2584 </span>    <span class="muControl">break-unless</span> delete-to-end-of-line?
<span id="L2585" class="LineNr">2585 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L2585'>&lt;begin-delete-to-end-of-line&gt;</a></span>
<span id="L2586" class="LineNr">2586 </span>    deleted-cells:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2612'>delete-to-end-of-line</a> editor
<span id="L2587" class="LineNr">2587 </span><span class="Constant">    <a href='003-shortcuts.mu.html#L2587'>&lt;end-delete-to-end-of-line&gt;</a></span>
<span id="L2588" class="LineNr">2588 </span>    <span class="Comment"># checks if we can do a minimal render and if we can it will do a minimal render</span>
<span id="L2589" class="LineNr">2589 </span>    go-render?:bool <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2594'>minimal-render-for-ctrl-k</a> <a href='../081print.mu.html#L16'>screen</a>, editor, deleted-cells
<span id="L2590" class="LineNr">2590 </span>   <span class="muControl"> return</span>
<span id="L2591" class="LineNr">2591 </span>  <span class="Delimiter">}</span>
<span id="L2592" class="LineNr">2592 </span>]
<span id="L2593" class="LineNr">2593 </span>
<span id="L2594" class="LineNr">2594 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L2594'>minimal-render-for-ctrl-k</a> <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a>, editor:&amp;:editor, deleted-cells:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char<span class="muRecipe"> -&gt; </span>go-render?:bool, <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a> [
<span id="L2595" class="LineNr">2595 </span>  <span class="Constant">local-scope</span>
<span id="L2596" class="LineNr">2596 </span>  <span class="Constant">load-inputs</span>
<span id="L2597" class="LineNr">2597 </span>  <span class="Comment"># if we deleted nothing, there's nothing to render</span>
<span id="L2598" class="LineNr">2598 </span>  <span class="muControl">return-unless</span> deleted-cells,<span class="Constant"> false/dont-render</span>
<span id="L2599" class="LineNr">2599 </span>  <span class="Comment"># if the line used to wrap before, give up and render the whole screen</span>
<span id="L2600" class="LineNr">2600 </span>  curr-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L2601" class="LineNr">2601 </span>  num-deleted-cells:num <span class="Special">&lt;-</span> length deleted-cells
<span id="L2602" class="LineNr">2602 </span>  old-row-len:num <span class="Special">&lt;-</span> add curr-column, num-deleted-cells
<span id="L2603" class="LineNr">2603 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L2604" class="LineNr">2604 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L2605" class="LineNr">2605 </span>  end:num <span class="Special">&lt;-</span> subtract right, left
<span id="L2606" class="LineNr">2606 </span>  wrap?:bool <span class="Special">&lt;-</span> greater-or-equal old-row-len, end
<span id="L2607" class="LineNr">2607 </span>  <span class="muControl">return-if</span> wrap?,<span class="Constant"> true/go-render</span>
<span id="L2608" class="LineNr">2608 </span>  <a href='../081print.mu.html#L553'>clear-line-until</a> <a href='../081print.mu.html#L16'>screen</a>, right
<span id="L2609" class="LineNr">2609 </span> <span class="muControl"> return</span><span class="Constant"> false/dont-render</span>
<span id="L2610" class="LineNr">2610 </span>]
<span id="L2611" class="LineNr">2611 </span>
<span id="L2612" class="LineNr">2612 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L2612'>delete-to-end-of-line</a> editor:&amp;:editor<span class="muRecipe"> -&gt; </span>result:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char, editor:&amp;:editor [
<span id="L2613" class="LineNr">2613 </span>  <span class="Constant">local-scope</span>
<span id="L2614" class="LineNr">2614 </span>  <span class="Constant">load-inputs</span>
<span id="L2615" class="LineNr">2615 </span>  <span class="Comment"># compute range to delete</span>
<span id="L2616" class="LineNr">2616 </span>  start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L2617" class="LineNr">2617 </span>  end:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> start
<span id="L2618" class="LineNr">2618 </span>  <span class="Delimiter">{</span>
<span id="L2619" class="LineNr">2619 </span>    at-end-of-text?:bool <span class="Special">&lt;-</span> equal end,<span class="Constant"> null</span>
<span id="L2620" class="LineNr">2620 </span>    <span class="muControl">break-if</span> at-end-of-text?
<span id="L2621" class="LineNr">2621 </span>    curr:char <span class="Special">&lt;-</span> get *end, <span class="Constant">value:offset</span>
<span id="L2622" class="LineNr">2622 </span>    at-end-of-line?:bool <span class="Special">&lt;-</span> equal curr, <span class="Constant">10/newline</span>
<span id="L2623" class="LineNr">2623 </span>    <span class="muControl">break-if</span> at-end-of-line?
<span id="L2624" class="LineNr">2624 </span>    end <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> end
<span id="L2625" class="LineNr">2625 </span>   <span class="muControl"> loop</span>
<span id="L2626" class="LineNr">2626 </span>  <span class="Delimiter">}</span>
<span id="L2627" class="LineNr">2627 </span>  <span class="Comment"># snip it out</span>
<span id="L2628" class="LineNr">2628 </span>  result <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> start
<span id="L2629" class="LineNr">2629 </span>  <a href='../065duplex_list.mu.html#L391'>remove-between</a> start, end
<span id="L2630" class="LineNr">2630 </span>]
<span id="L2631" class="LineNr">2631 </span>
<span id="L2632" class="LineNr">2632 </span><span class="muScenario">scenario</span> editor-deletes-to-end-of-line-with-ctrl-k-2 [
<span id="L2633" class="LineNr">2633 </span>  <span class="Constant">local-scope</span>
<span id="L2634" class="LineNr">2634 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L2635" class="LineNr">2635 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L2636" class="LineNr">2636 </span><span class="Constant">456]</span>
<span id="L2637" class="LineNr">2637 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L2638" class="LineNr">2638 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2639" class="LineNr">2639 </span>  $clear-trace
<span id="L2640" class="LineNr">2640 </span>  <span class="Comment"># start on second line (no newline after), press ctrl-k</span>
<span id="L2641" class="LineNr">2641 </span>  assume-console [
<span id="L2642" class="LineNr">2642 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 1</span>
<span id="L2643" class="LineNr">2643 </span>    press ctrl-k
<span id="L2644" class="LineNr">2644 </span>  ]
<span id="L2645" class="LineNr">2645 </span>  run [
<span id="L2646" class="LineNr">2646 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2647" class="LineNr">2647 </span>  ]
<span id="L2648" class="LineNr">2648 </span>  <span class="Comment"># cursor deletes to end of line</span>
<span id="L2649" class="LineNr">2649 </span>  screen-should-contain [
<span id="L2650" class="LineNr">2650 </span>   <span class="Constant"> .          .</span>
<span id="L2651" class="LineNr">2651 </span>   <span class="Constant"> .123       .</span>
<span id="L2652" class="LineNr">2652 </span>   <span class="Constant"> .4         .</span>
<span id="L2653" class="LineNr">2653 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2654" class="LineNr">2654 </span>   <span class="Constant"> .          .</span>
<span id="L2655" class="LineNr">2655 </span>  ]
<span id="L2656" class="LineNr">2656 </span>  check-trace-count-for-label<span class="Constant"> 9</span>, <span class="Constant">[print-character]</span>
<span id="L2657" class="LineNr">2657 </span>]
<span id="L2658" class="LineNr">2658 </span>
<span id="L2659" class="LineNr">2659 </span><span class="muScenario">scenario</span> editor-deletes-to-end-of-line-with-ctrl-k-3 [
<span id="L2660" class="LineNr">2660 </span>  <span class="Constant">local-scope</span>
<span id="L2661" class="LineNr">2661 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L2662" class="LineNr">2662 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L2663" class="LineNr">2663 </span><span class="Constant">456]</span>
<span id="L2664" class="LineNr">2664 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L2665" class="LineNr">2665 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2666" class="LineNr">2666 </span>  $clear-trace
<span id="L2667" class="LineNr">2667 </span>  <span class="Comment"># start at end of line</span>
<span id="L2668" class="LineNr">2668 </span>  assume-console [
<span id="L2669" class="LineNr">2669 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 2</span>
<span id="L2670" class="LineNr">2670 </span>    press ctrl-k
<span id="L2671" class="LineNr">2671 </span>  ]
<span id="L2672" class="LineNr">2672 </span>  run [
<span id="L2673" class="LineNr">2673 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2674" class="LineNr">2674 </span>  ]
<span id="L2675" class="LineNr">2675 </span>  <span class="Comment"># cursor deletes just last character</span>
<span id="L2676" class="LineNr">2676 </span>  screen-should-contain [
<span id="L2677" class="LineNr">2677 </span>   <span class="Constant"> .          .</span>
<span id="L2678" class="LineNr">2678 </span>   <span class="Constant"> .12        .</span>
<span id="L2679" class="LineNr">2679 </span>   <span class="Constant"> .456       .</span>
<span id="L2680" class="LineNr">2680 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2681" class="LineNr">2681 </span>   <span class="Constant"> .          .</span>
<span id="L2682" class="LineNr">2682 </span>  ]
<span id="L2683" class="LineNr">2683 </span>  check-trace-count-for-label<span class="Constant"> 8</span>, <span class="Constant">[print-character]</span>
<span id="L2684" class="LineNr">2684 </span>]
<span id="L2685" class="LineNr">2685 </span>
<span id="L2686" class="LineNr">2686 </span><span class="muScenario">scenario</span> editor-deletes-to-end-of-line-with-ctrl-k-4 [
<span id="L2687" class="LineNr">2687 </span>  <span class="Constant">local-scope</span>
<span id="L2688" class="LineNr">2688 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L2689" class="LineNr">2689 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L2690" class="LineNr">2690 </span><span class="Constant">456]</span>
<span id="L2691" class="LineNr">2691 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L2692" class="LineNr">2692 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2693" class="LineNr">2693 </span>  $clear-trace
<span id="L2694" class="LineNr">2694 </span>  <span class="Comment"># start past end of line</span>
<span id="L2695" class="LineNr">2695 </span>  assume-console [
<span id="L2696" class="LineNr">2696 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 3</span>
<span id="L2697" class="LineNr">2697 </span>    press ctrl-k
<span id="L2698" class="LineNr">2698 </span>  ]
<span id="L2699" class="LineNr">2699 </span>  run [
<span id="L2700" class="LineNr">2700 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2701" class="LineNr">2701 </span>  ]
<span id="L2702" class="LineNr">2702 </span>  <span class="Comment"># cursor deletes nothing</span>
<span id="L2703" class="LineNr">2703 </span>  screen-should-contain [
<span id="L2704" class="LineNr">2704 </span>   <span class="Constant"> .          .</span>
<span id="L2705" class="LineNr">2705 </span>   <span class="Constant"> .123       .</span>
<span id="L2706" class="LineNr">2706 </span>   <span class="Constant"> .456       .</span>
<span id="L2707" class="LineNr">2707 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2708" class="LineNr">2708 </span>   <span class="Constant"> .          .</span>
<span id="L2709" class="LineNr">2709 </span>  ]
<span id="L2710" class="LineNr">2710 </span>  check-trace-count-for-label<span class="Constant"> 7</span>, <span class="Constant">[print-character]</span>
<span id="L2711" class="LineNr">2711 </span>]
<span id="L2712" class="LineNr">2712 </span>
<span id="L2713" class="LineNr">2713 </span><span class="muScenario">scenario</span> editor-deletes-to-end-of-line-with-ctrl-k-5 [
<span id="L2714" class="LineNr">2714 </span>  <span class="Constant">local-scope</span>
<span id="L2715" class="LineNr">2715 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L2716" class="LineNr">2716 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L2717" class="LineNr">2717 </span><span class="Constant">456]</span>
<span id="L2718" class="LineNr">2718 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L2719" class="LineNr">2719 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2720" class="LineNr">2720 </span>  $clear-trace
<span id="L2721" class="LineNr">2721 </span>  <span class="Comment"># start at end of text</span>
<span id="L2722" class="LineNr">2722 </span>  assume-console [
<span id="L2723" class="LineNr">2723 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 2</span>
<span id="L2724" class="LineNr">2724 </span>    press ctrl-k
<span id="L2725" class="LineNr">2725 </span>  ]
<span id="L2726" class="LineNr">2726 </span>  run [
<span id="L2727" class="LineNr">2727 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2728" class="LineNr">2728 </span>  ]
<span id="L2729" class="LineNr">2729 </span>  <span class="Comment"># cursor deletes just the final character</span>
<span id="L2730" class="LineNr">2730 </span>  screen-should-contain [
<span id="L2731" class="LineNr">2731 </span>   <span class="Constant"> .          .</span>
<span id="L2732" class="LineNr">2732 </span>   <span class="Constant"> .123       .</span>
<span id="L2733" class="LineNr">2733 </span>   <span class="Constant"> .45        .</span>
<span id="L2734" class="LineNr">2734 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2735" class="LineNr">2735 </span>   <span class="Constant"> .          .</span>
<span id="L2736" class="LineNr">2736 </span>  ]
<span id="L2737" class="LineNr">2737 </span>  check-trace-count-for-label<span class="Constant"> 8</span>, <span class="Constant">[print-character]</span>
<span id="L2738" class="LineNr">2738 </span>]
<span id="L2739" class="LineNr">2739 </span>
<span id="L2740" class="LineNr">2740 </span><span class="muScenario">scenario</span> editor-deletes-to-end-of-line-with-ctrl-k-6 [
<span id="L2741" class="LineNr">2741 </span>  <span class="Constant">local-scope</span>
<span id="L2742" class="LineNr">2742 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L2743" class="LineNr">2743 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[123</span>
<span id="L2744" class="LineNr">2744 </span><span class="Constant">456]</span>
<span id="L2745" class="LineNr">2745 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L2746" class="LineNr">2746 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2747" class="LineNr">2747 </span>  $clear-trace
<span id="L2748" class="LineNr">2748 </span>  <span class="Comment"># start past end of text</span>
<span id="L2749" class="LineNr">2749 </span>  assume-console [
<span id="L2750" class="LineNr">2750 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 3</span>
<span id="L2751" class="LineNr">2751 </span>    press ctrl-k
<span id="L2752" class="LineNr">2752 </span>  ]
<span id="L2753" class="LineNr">2753 </span>  run [
<span id="L2754" class="LineNr">2754 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2755" class="LineNr">2755 </span>  ]
<span id="L2756" class="LineNr">2756 </span>  <span class="Comment"># cursor deletes nothing</span>
<span id="L2757" class="LineNr">2757 </span>  screen-should-contain [
<span id="L2758" class="LineNr">2758 </span>   <span class="Constant"> .          .</span>
<span id="L2759" class="LineNr">2759 </span>   <span class="Constant"> .123       .</span>
<span id="L2760" class="LineNr">2760 </span>   <span class="Constant"> .456       .</span>
<span id="L2761" class="LineNr">2761 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L2762" class="LineNr">2762 </span>   <span class="Constant"> .          .</span>
<span id="L2763" class="LineNr">2763 </span>  ]
<span id="L2764" class="LineNr">2764 </span>  <span class="Comment"># no prints necessary</span>
<span id="L2765" class="LineNr">2765 </span>  check-trace-count-for-label<span class="Constant"> 0</span>, <span class="Constant">[print-character]</span>
<span id="L2766" class="LineNr">2766 </span>]
<span id="L2767" class="LineNr">2767 </span>
<span id="L2768" class="LineNr">2768 </span><span class="muScenario">scenario</span> editor-deletes-to-end-of-wrapped-line-with-ctrl-k [
<span id="L2769" class="LineNr">2769 </span>  <span class="Constant">local-scope</span>
<span id="L2770" class="LineNr">2770 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L2771" class="LineNr">2771 </span>  <span class="Comment"># create an editor with the first line wrapping to a second screen row</span>
<span id="L2772" class="LineNr">2772 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[1234</span>
<span id="L2773" class="LineNr">2773 </span><span class="Constant">567]</span>
<span id="L2774" class="LineNr">2774 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">4/right</span>
<span id="L2775" class="LineNr">2775 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2776" class="LineNr">2776 </span>  $clear-trace
<span id="L2777" class="LineNr">2777 </span>  <span class="Comment"># delete all of the first wrapped line</span>
<span id="L2778" class="LineNr">2778 </span>  assume-console [
<span id="L2779" class="LineNr">2779 </span>    press ctrl-k
<span id="L2780" class="LineNr">2780 </span>  ]
<span id="L2781" class="LineNr">2781 </span>  run [
<span id="L2782" class="LineNr">2782 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2783" class="LineNr">2783 </span>  ]
<span id="L2784" class="LineNr">2784 </span>  <span class="Comment"># screen shows an empty unwrapped first line</span>
<span id="L2785" class="LineNr">2785 </span>  screen-should-contain [
<span id="L2786" class="LineNr">2786 </span>   <span class="Constant"> .          .</span>
<span id="L2787" class="LineNr">2787 </span>   <span class="Constant"> .          .</span>
<span id="L2788" class="LineNr">2788 </span>   <span class="Constant"> .567       .</span>
<span id="L2789" class="LineNr">2789 </span>   <span class="Constant"> .╌╌╌╌      .</span>
<span id="L2790" class="LineNr">2790 </span>   <span class="Constant"> .          .</span>
<span id="L2791" class="LineNr">2791 </span>  ]
<span id="L2792" class="LineNr">2792 </span>  <span class="Comment"># entire screen is refreshed</span>
<span id="L2793" class="LineNr">2793 </span>  check-trace-count-for-label<span class="Constant"> 16</span>, <span class="Constant">[print-character]</span>
<span id="L2794" class="LineNr">2794 </span>]
<span id="L2795" class="LineNr">2795 </span>
<span id="L2796" class="LineNr">2796 </span><span class="Comment"># scroll down if necessary</span>
<span id="L2797" class="LineNr">2797 </span>
<span id="L2798" class="LineNr">2798 </span><span class="muScenario">scenario</span> editor-can-scroll-down-using-arrow-keys [
<span id="L2799" class="LineNr">2799 </span>  <span class="Constant">local-scope</span>
<span id="L2800" class="LineNr">2800 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L2801" class="LineNr">2801 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L2802" class="LineNr">2802 </span>  <span class="Comment"># initialize editor with &gt;3 lines</span>
<span id="L2803" class="LineNr">2803 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L2804" class="LineNr">2804 </span><span class="Constant">b</span>
<span id="L2805" class="LineNr">2805 </span><span class="Constant">c</span>
<span id="L2806" class="LineNr">2806 </span><span class="Constant">d]</span>
<span id="L2807" class="LineNr">2807 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L2808" class="LineNr">2808 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2809" class="LineNr">2809 </span>  screen-should-contain [
<span id="L2810" class="LineNr">2810 </span>   <span class="Constant"> .          .</span>
<span id="L2811" class="LineNr">2811 </span>   <span class="Constant"> .a         .</span>
<span id="L2812" class="LineNr">2812 </span>   <span class="Constant"> .b         .</span>
<span id="L2813" class="LineNr">2813 </span>   <span class="Constant"> .c         .</span>
<span id="L2814" class="LineNr">2814 </span>  ]
<span id="L2815" class="LineNr">2815 </span>  <span class="Comment"># position cursor at last line, then try to move further down</span>
<span id="L2816" class="LineNr">2816 </span>  assume-console [
<span id="L2817" class="LineNr">2817 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
<span id="L2818" class="LineNr">2818 </span>    press down-arrow
<span id="L2819" class="LineNr">2819 </span>  ]
<span id="L2820" class="LineNr">2820 </span>  run [
<span id="L2821" class="LineNr">2821 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2822" class="LineNr">2822 </span>  ]
<span id="L2823" class="LineNr">2823 </span>  <span class="Comment"># screen slides by one line</span>
<span id="L2824" class="LineNr">2824 </span>  screen-should-contain [
<span id="L2825" class="LineNr">2825 </span>   <span class="Constant"> .          .</span>
<span id="L2826" class="LineNr">2826 </span>   <span class="Constant"> .b         .</span>
<span id="L2827" class="LineNr">2827 </span>   <span class="Constant"> .c         .</span>
<span id="L2828" class="LineNr">2828 </span>   <span class="Constant"> .d         .</span>
<span id="L2829" class="LineNr">2829 </span>  ]
<span id="L2830" class="LineNr">2830 </span>]
<span id="L2831" class="LineNr">2831 </span>
<span id="L2832" class="LineNr">2832 </span><span class="muRecipe">after</span> <span class="Constant">&lt;scroll-down&gt;</span> [
<span id="L2833" class="LineNr">2833 </span>  trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[scroll down]</span>
<span id="L2834" class="LineNr">2834 </span>  top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L2835" class="LineNr">2835 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L2836" class="LineNr">2836 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L2837" class="LineNr">2837 </span>  max:num <span class="Special">&lt;-</span> subtract right, left
<span id="L2838" class="LineNr">2838 </span>  old-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy top-of-screen
<span id="L2839" class="LineNr">2839 </span>  top-of-screen <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2862'>before-start-of-next-line</a> top-of-screen, max
<span id="L2840" class="LineNr">2840 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top-of-screen
<span id="L2841" class="LineNr">2841 </span>  no-movement?:bool <span class="Special">&lt;-</span> equal old-top, top-of-screen
<span id="L2842" class="LineNr">2842 </span>  <span class="muControl">return-if</span> no-movement?,<span class="Constant"> false/don't-render</span>
<span id="L2843" class="LineNr">2843 </span>]
<span id="L2844" class="LineNr">2844 </span>
<span id="L2845" class="LineNr">2845 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L888'>&lt;scroll-down2&gt;</a></span> [
<span id="L2846" class="LineNr">2846 </span>  trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[scroll down]</span>
<span id="L2847" class="LineNr">2847 </span>  top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L2848" class="LineNr">2848 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L2849" class="LineNr">2849 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L2850" class="LineNr">2850 </span>  max:num <span class="Special">&lt;-</span> subtract right, left
<span id="L2851" class="LineNr">2851 </span>  old-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy top-of-screen
<span id="L2852" class="LineNr">2852 </span>  top-of-screen <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2862'>before-start-of-next-line</a> top-of-screen, max
<span id="L2853" class="LineNr">2853 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top-of-screen
<span id="L2854" class="LineNr">2854 </span>  no-movement?:bool <span class="Special">&lt;-</span> equal old-top, top-of-screen
<span id="L2855" class="LineNr">2855 </span>  <span class="muControl">return-if</span> no-movement?
<span id="L2856" class="LineNr">2856 </span>]
<span id="L2857" class="LineNr">2857 </span>
<span id="L2858" class="LineNr">2858 </span><span class="Comment"># Takes a pointer into the doubly-linked list, scans ahead at most 'max'</span>
<span id="L2859" class="LineNr">2859 </span><span class="Comment"># positions until the next newline.</span>
<span id="L2860" class="LineNr">2860 </span><span class="Comment"># Returns original if no next newline.</span>
<span id="L2861" class="LineNr">2861 </span><span class="Comment"># Beware: never return null pointer.</span>
<span id="L2862" class="LineNr">2862 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L2862'>before-start-of-next-line</a> original:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char, max:num<span class="muRecipe"> -&gt; </span>curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char [
<span id="L2863" class="LineNr">2863 </span>  <span class="Constant">local-scope</span>
<span id="L2864" class="LineNr">2864 </span>  <span class="Constant">load-inputs</span>
<span id="L2865" class="LineNr">2865 </span>  count:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
<span id="L2866" class="LineNr">2866 </span>  curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy original
<span id="L2867" class="LineNr">2867 </span>  <span class="Comment"># skip the initial newline if it exists</span>
<span id="L2868" class="LineNr">2868 </span>  <span class="Delimiter">{</span>
<span id="L2869" class="LineNr">2869 </span>    c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
<span id="L2870" class="LineNr">2870 </span>    at-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
<span id="L2871" class="LineNr">2871 </span>    <span class="muControl">break-unless</span> at-newline?
<span id="L2872" class="LineNr">2872 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> curr
<span id="L2873" class="LineNr">2873 </span>    count <span class="Special">&lt;-</span> add count,<span class="Constant"> 1</span>
<span id="L2874" class="LineNr">2874 </span>  <span class="Delimiter">}</span>
<span id="L2875" class="LineNr">2875 </span>  <span class="Delimiter">{</span>
<span id="L2876" class="LineNr">2876 </span>    <span class="muControl">return-unless</span> curr, original
<span id="L2877" class="LineNr">2877 </span>    done?:bool <span class="Special">&lt;-</span> greater-or-equal count, max
<span id="L2878" class="LineNr">2878 </span>    <span class="muControl">break-if</span> done?
<span id="L2879" class="LineNr">2879 </span>    c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
<span id="L2880" class="LineNr">2880 </span>    at-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
<span id="L2881" class="LineNr">2881 </span>    <span class="muControl">break-if</span> at-newline?
<span id="L2882" class="LineNr">2882 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> curr
<span id="L2883" class="LineNr">2883 </span>    count <span class="Special">&lt;-</span> add count,<span class="Constant"> 1</span>
<span id="L2884" class="LineNr">2884 </span>   <span class="muControl"> loop</span>
<span id="L2885" class="LineNr">2885 </span>  <span class="Delimiter">}</span>
<span id="L2886" class="LineNr">2886 </span>  <span class="muControl">return-unless</span> curr, original
<span id="L2887" class="LineNr">2887 </span> <span class="muControl"> return</span> curr
<span id="L2888" class="LineNr">2888 </span>]
<span id="L2889" class="LineNr">2889 </span>
<span id="L2890" class="LineNr">2890 </span><span class="muScenario">scenario</span> editor-scrolls-down-past-wrapped-line-using-arrow-keys [
<span id="L2891" class="LineNr">2891 </span>  <span class="Constant">local-scope</span>
<span id="L2892" class="LineNr">2892 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L2893" class="LineNr">2893 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L2894" class="LineNr">2894 </span>  <span class="Comment"># initialize editor with a long, wrapped line and more than a screen of</span>
<span id="L2895" class="LineNr">2895 </span>  <span class="Comment"># other lines</span>
<span id="L2896" class="LineNr">2896 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abcdef</span>
<span id="L2897" class="LineNr">2897 </span><span class="Constant">g</span>
<span id="L2898" class="LineNr">2898 </span><span class="Constant">h</span>
<span id="L2899" class="LineNr">2899 </span><span class="Constant">i]</span>
<span id="L2900" class="LineNr">2900 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L2901" class="LineNr">2901 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L2902" class="LineNr">2902 </span>  screen-should-contain [
<span id="L2903" class="LineNr">2903 </span>   <span class="Constant"> .          .</span>
<span id="L2904" class="LineNr">2904 </span>   <span class="Constant"> .abcd↩     .</span>
<span id="L2905" class="LineNr">2905 </span>   <span class="Constant"> .ef        .</span>
<span id="L2906" class="LineNr">2906 </span>   <span class="Constant"> .g         .</span>
<span id="L2907" class="LineNr">2907 </span>  ]
<span id="L2908" class="LineNr">2908 </span>  <span class="Comment"># position cursor at last line, then try to move further down</span>
<span id="L2909" class="LineNr">2909 </span>  assume-console [
<span id="L2910" class="LineNr">2910 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
<span id="L2911" class="LineNr">2911 </span>    press down-arrow
<span id="L2912" class="LineNr">2912 </span>  ]
<span id="L2913" class="LineNr">2913 </span>  run [
<span id="L2914" class="LineNr">2914 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2915" class="LineNr">2915 </span>  ]
<span id="L2916" class="LineNr">2916 </span>  <span class="Comment"># screen shows partial wrapped line</span>
<span id="L2917" class="LineNr">2917 </span>  screen-should-contain [
<span id="L2918" class="LineNr">2918 </span>   <span class="Constant"> .          .</span>
<span id="L2919" class="LineNr">2919 </span>   <span class="Constant"> .ef        .</span>
<span id="L2920" class="LineNr">2920 </span>   <span class="Constant"> .g         .</span>
<span id="L2921" class="LineNr">2921 </span>   <span class="Constant"> .h         .</span>
<span id="L2922" class="LineNr">2922 </span>  ]
<span id="L2923" class="LineNr">2923 </span>]
<span id="L2924" class="LineNr">2924 </span>
<span id="L2925" class="LineNr">2925 </span><span class="muScenario">scenario</span> editor-scrolls-down-past-wrapped-line-using-arrow-keys-2 [
<span id="L2926" class="LineNr">2926 </span>  <span class="Constant">local-scope</span>
<span id="L2927" class="LineNr">2927 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L2928" class="LineNr">2928 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L2929" class="LineNr">2929 </span>  <span class="Comment"># editor starts with a long line wrapping twice</span>
<span id="L2930" class="LineNr">2930 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abcdefghij</span>
<span id="L2931" class="LineNr">2931 </span><span class="Constant">k</span>
<span id="L2932" class="LineNr">2932 </span><span class="Constant">l</span>
<span id="L2933" class="LineNr">2933 </span><span class="Constant">m]</span>
<span id="L2934" class="LineNr">2934 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L2935" class="LineNr">2935 </span>  <span class="Comment"># position cursor at last line, then try to move further down</span>
<span id="L2936" class="LineNr">2936 </span>  assume-console [
<span id="L2937" class="LineNr">2937 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
<span id="L2938" class="LineNr">2938 </span>    press down-arrow
<span id="L2939" class="LineNr">2939 </span>  ]
<span id="L2940" class="LineNr">2940 </span>  run [
<span id="L2941" class="LineNr">2941 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2942" class="LineNr">2942 </span>  ]
<span id="L2943" class="LineNr">2943 </span>  <span class="Comment"># screen shows partial wrapped line containing a wrap icon</span>
<span id="L2944" class="LineNr">2944 </span>  screen-should-contain [
<span id="L2945" class="LineNr">2945 </span>   <span class="Constant"> .          .</span>
<span id="L2946" class="LineNr">2946 </span>   <span class="Constant"> .efgh↩     .</span>
<span id="L2947" class="LineNr">2947 </span>   <span class="Constant"> .ij        .</span>
<span id="L2948" class="LineNr">2948 </span>   <span class="Constant"> .k         .</span>
<span id="L2949" class="LineNr">2949 </span>  ]
<span id="L2950" class="LineNr">2950 </span>  <span class="Comment"># scroll down again</span>
<span id="L2951" class="LineNr">2951 </span>  assume-console [
<span id="L2952" class="LineNr">2952 </span>    press down-arrow
<span id="L2953" class="LineNr">2953 </span>  ]
<span id="L2954" class="LineNr">2954 </span>  run [
<span id="L2955" class="LineNr">2955 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2956" class="LineNr">2956 </span>  ]
<span id="L2957" class="LineNr">2957 </span>  <span class="Comment"># screen shows partial wrapped line</span>
<span id="L2958" class="LineNr">2958 </span>  screen-should-contain [
<span id="L2959" class="LineNr">2959 </span>   <span class="Constant"> .          .</span>
<span id="L2960" class="LineNr">2960 </span>   <span class="Constant"> .ij        .</span>
<span id="L2961" class="LineNr">2961 </span>   <span class="Constant"> .k         .</span>
<span id="L2962" class="LineNr">2962 </span>   <span class="Constant"> .l         .</span>
<span id="L2963" class="LineNr">2963 </span>  ]
<span id="L2964" class="LineNr">2964 </span>]
<span id="L2965" class="LineNr">2965 </span>
<span id="L2966" class="LineNr">2966 </span><span class="muScenario">scenario</span> editor-scrolls-down-when-line-wraps [
<span id="L2967" class="LineNr">2967 </span>  <span class="Constant">local-scope</span>
<span id="L2968" class="LineNr">2968 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L2969" class="LineNr">2969 </span>  assume-screen <span class="Constant">5/width</span>, <span class="Constant">4/height</span>
<span id="L2970" class="LineNr">2970 </span>  <span class="Comment"># editor contains a long line in the third line</span>
<span id="L2971" class="LineNr">2971 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L2972" class="LineNr">2972 </span><span class="Constant">b</span>
<span id="L2973" class="LineNr">2973 </span><span class="Constant">cdef]</span>
<span id="L2974" class="LineNr">2974 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L2975" class="LineNr">2975 </span>  <span class="Comment"># position cursor at end, type a character</span>
<span id="L2976" class="LineNr">2976 </span>  assume-console [
<span id="L2977" class="LineNr">2977 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 4</span>
<span id="L2978" class="LineNr">2978 </span>    type <span class="Constant">[g]</span>
<span id="L2979" class="LineNr">2979 </span>  ]
<span id="L2980" class="LineNr">2980 </span>  run [
<span id="L2981" class="LineNr">2981 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L2982" class="LineNr">2982 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L2983" class="LineNr">2983 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L2984" class="LineNr">2984 </span>  ]
<span id="L2985" class="LineNr">2985 </span>  <span class="Comment"># screen scrolls</span>
<span id="L2986" class="LineNr">2986 </span>  screen-should-contain [
<span id="L2987" class="LineNr">2987 </span>   <span class="Constant"> .     .</span>
<span id="L2988" class="LineNr">2988 </span>   <span class="Constant"> .b    .</span>
<span id="L2989" class="LineNr">2989 </span><span class="Constant">    .cdef↩.</span>
<span id="L2990" class="LineNr">2990 </span>   <span class="Constant"> .g    .</span>
<span id="L2991" class="LineNr">2991 </span>  ]
<span id="L2992" class="LineNr">2992 </span>  memory-should-contain [
<span id="L2993" class="LineNr">2993 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L2994" class="LineNr">2994 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L2995" class="LineNr">2995 </span>  ]
<span id="L2996" class="LineNr">2996 </span>]
<span id="L2997" class="LineNr">2997 </span>
<span id="L2998" class="LineNr">2998 </span><span class="muScenario">scenario</span> editor-stops-scrolling-once-bottom-is-visible [
<span id="L2999" class="LineNr">2999 </span>  <span class="Constant">local-scope</span>
<span id="L3000" class="LineNr">3000 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L3001" class="LineNr">3001 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3002" class="LineNr">3002 </span>  <span class="Comment"># initialize editor with 2 lines</span>
<span id="L3003" class="LineNr">3003 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3004" class="LineNr">3004 </span><span class="Constant">b]</span>
<span id="L3005" class="LineNr">3005 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L3006" class="LineNr">3006 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3007" class="LineNr">3007 </span>  screen-should-contain [
<span id="L3008" class="LineNr">3008 </span>   <span class="Constant"> .          .</span>
<span id="L3009" class="LineNr">3009 </span>   <span class="Constant"> .a         .</span>
<span id="L3010" class="LineNr">3010 </span>   <span class="Constant"> .b         .</span>
<span id="L3011" class="LineNr">3011 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L3012" class="LineNr">3012 </span>  ]
<span id="L3013" class="LineNr">3013 </span>  <span class="Comment"># position cursor at last line, then try to move further down</span>
<span id="L3014" class="LineNr">3014 </span>  assume-console [
<span id="L3015" class="LineNr">3015 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
<span id="L3016" class="LineNr">3016 </span>    press down-arrow
<span id="L3017" class="LineNr">3017 </span>  ]
<span id="L3018" class="LineNr">3018 </span>  run [
<span id="L3019" class="LineNr">3019 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3020" class="LineNr">3020 </span>  ]
<span id="L3021" class="LineNr">3021 </span>  <span class="Comment"># no change since the bottom border was already visible</span>
<span id="L3022" class="LineNr">3022 </span>  screen-should-contain [
<span id="L3023" class="LineNr">3023 </span>   <span class="Constant"> .          .</span>
<span id="L3024" class="LineNr">3024 </span>   <span class="Constant"> .a         .</span>
<span id="L3025" class="LineNr">3025 </span>   <span class="Constant"> .b         .</span>
<span id="L3026" class="LineNr">3026 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L3027" class="LineNr">3027 </span>  ]
<span id="L3028" class="LineNr">3028 </span>]
<span id="L3029" class="LineNr">3029 </span>
<span id="L3030" class="LineNr">3030 </span><span class="muScenario">scenario</span> editor-scrolls-down-on-newline [
<span id="L3031" class="LineNr">3031 </span>  <span class="Constant">local-scope</span>
<span id="L3032" class="LineNr">3032 </span>  assume-screen <span class="Constant">5/width</span>, <span class="Constant">4/height</span>
<span id="L3033" class="LineNr">3033 </span>  <span class="Comment"># position cursor after last line and type newline</span>
<span id="L3034" class="LineNr">3034 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3035" class="LineNr">3035 </span><span class="Constant">b</span>
<span id="L3036" class="LineNr">3036 </span><span class="Constant">c]</span>
<span id="L3037" class="LineNr">3037 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L3038" class="LineNr">3038 </span>  assume-console [
<span id="L3039" class="LineNr">3039 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 4</span>
<span id="L3040" class="LineNr">3040 </span>    type [
<span id="L3041" class="LineNr">3041 </span>]
<span id="L3042" class="LineNr">3042 </span>  ]
<span id="L3043" class="LineNr">3043 </span>  run [
<span id="L3044" class="LineNr">3044 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3045" class="LineNr">3045 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L3046" class="LineNr">3046 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L3047" class="LineNr">3047 </span>  ]
<span id="L3048" class="LineNr">3048 </span>  <span class="Comment"># screen scrolls</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"> .b    .</span>
<span id="L3052" class="LineNr">3052 </span>   <span class="Constant"> .c    .</span>
<span id="L3053" class="LineNr">3053 </span>   <span class="Constant"> .     .</span>
<span id="L3054" class="LineNr">3054 </span>  ]
<span id="L3055" class="LineNr">3055 </span>  memory-should-contain [
<span id="L3056" class="LineNr">3056 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L3057" class="LineNr">3057 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L3058" class="LineNr">3058 </span>  ]
<span id="L3059" class="LineNr">3059 </span>]
<span id="L3060" class="LineNr">3060 </span>
<span id="L3061" class="LineNr">3061 </span><span class="muScenario">scenario</span> editor-scrolls-down-on-right-arrow [
<span id="L3062" class="LineNr">3062 </span>  <span class="Constant">local-scope</span>
<span id="L3063" class="LineNr">3063 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L3064" class="LineNr">3064 </span>  assume-screen <span class="Constant">5/width</span>, <span class="Constant">4/height</span>
<span id="L3065" class="LineNr">3065 </span>  <span class="Comment"># editor contains a wrapped line</span>
<span id="L3066" class="LineNr">3066 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3067" class="LineNr">3067 </span><span class="Constant">b</span>
<span id="L3068" class="LineNr">3068 </span><span class="Constant">cdefgh]</span>
<span id="L3069" class="LineNr">3069 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L3070" class="LineNr">3070 </span>  <span class="Comment"># position cursor at end of screen and try to move right</span>
<span id="L3071" class="LineNr">3071 </span>  assume-console [
<span id="L3072" class="LineNr">3072 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 3</span>
<span id="L3073" class="LineNr">3073 </span>    press right-arrow
<span id="L3074" class="LineNr">3074 </span>  ]
<span id="L3075" class="LineNr">3075 </span>  run [
<span id="L3076" class="LineNr">3076 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3077" class="LineNr">3077 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L3078" class="LineNr">3078 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L3079" class="LineNr">3079 </span>  ]
<span id="L3080" class="LineNr">3080 </span>  <span class="Comment"># screen scrolls</span>
<span id="L3081" class="LineNr">3081 </span>  screen-should-contain [
<span id="L3082" class="LineNr">3082 </span>   <span class="Constant"> .     .</span>
<span id="L3083" class="LineNr">3083 </span>   <span class="Constant"> .b    .</span>
<span id="L3084" class="LineNr">3084 </span><span class="Constant">    .cdef↩.</span>
<span id="L3085" class="LineNr">3085 </span>   <span class="Constant"> .gh   .</span>
<span id="L3086" class="LineNr">3086 </span>  ]
<span id="L3087" class="LineNr">3087 </span>  memory-should-contain [
<span id="L3088" class="LineNr">3088 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L3089" class="LineNr">3089 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L3090" class="LineNr">3090 </span>  ]
<span id="L3091" class="LineNr">3091 </span>]
<span id="L3092" class="LineNr">3092 </span>
<span id="L3093" class="LineNr">3093 </span><span class="muScenario">scenario</span> editor-scrolls-down-on-right-arrow-2 [
<span id="L3094" class="LineNr">3094 </span>  <span class="Constant">local-scope</span>
<span id="L3095" class="LineNr">3095 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L3096" class="LineNr">3096 </span>  assume-screen <span class="Constant">5/width</span>, <span class="Constant">4/height</span>
<span id="L3097" class="LineNr">3097 </span>  <span class="Comment"># editor contains more lines than can fit on screen</span>
<span id="L3098" class="LineNr">3098 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3099" class="LineNr">3099 </span><span class="Constant">b</span>
<span id="L3100" class="LineNr">3100 </span><span class="Constant">c</span>
<span id="L3101" class="LineNr">3101 </span><span class="Constant">d]</span>
<span id="L3102" class="LineNr">3102 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L3103" class="LineNr">3103 </span>  <span class="Comment"># position cursor at end of screen and try to move right</span>
<span id="L3104" class="LineNr">3104 </span>  assume-console [
<span id="L3105" class="LineNr">3105 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 3</span>
<span id="L3106" class="LineNr">3106 </span>    press right-arrow
<span id="L3107" class="LineNr">3107 </span>  ]
<span id="L3108" class="LineNr">3108 </span>  run [
<span id="L3109" class="LineNr">3109 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3110" class="LineNr">3110 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L3111" class="LineNr">3111 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L3112" class="LineNr">3112 </span>  ]
<span id="L3113" class="LineNr">3113 </span>  <span class="Comment"># screen scrolls</span>
<span id="L3114" class="LineNr">3114 </span>  screen-should-contain [
<span id="L3115" class="LineNr">3115 </span>   <span class="Constant"> .     .</span>
<span id="L3116" class="LineNr">3116 </span>   <span class="Constant"> .b    .</span>
<span id="L3117" class="LineNr">3117 </span>   <span class="Constant"> .c    .</span>
<span id="L3118" class="LineNr">3118 </span>   <span class="Constant"> .d    .</span>
<span id="L3119" class="LineNr">3119 </span>  ]
<span id="L3120" class="LineNr">3120 </span>  memory-should-contain [
<span id="L3121" class="LineNr">3121 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L3122" class="LineNr">3122 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L3123" class="LineNr">3123 </span>  ]
<span id="L3124" class="LineNr">3124 </span>]
<span id="L3125" class="LineNr">3125 </span>
<span id="L3126" class="LineNr">3126 </span><span class="muScenario">scenario</span> editor-scrolls-at-end-on-down-arrow [
<span id="L3127" class="LineNr">3127 </span>  <span class="Constant">local-scope</span>
<span id="L3128" class="LineNr">3128 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L3129" class="LineNr">3129 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abc</span>
<span id="L3130" class="LineNr">3130 </span><span class="Constant">de]</span>
<span id="L3131" class="LineNr">3131 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L3132" class="LineNr">3132 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3133" class="LineNr">3133 </span>  $clear-trace
<span id="L3134" class="LineNr">3134 </span>  <span class="Comment"># try to move down past end of text</span>
<span id="L3135" class="LineNr">3135 </span>  assume-console [
<span id="L3136" class="LineNr">3136 </span>    left-click<span class="Constant"> 2</span>,<span class="Constant"> 0</span>
<span id="L3137" class="LineNr">3137 </span>    press down-arrow
<span id="L3138" class="LineNr">3138 </span>  ]
<span id="L3139" class="LineNr">3139 </span>  run [
<span id="L3140" class="LineNr">3140 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3141" class="LineNr">3141 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L3142" class="LineNr">3142 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L3143" class="LineNr">3143 </span>  ]
<span id="L3144" class="LineNr">3144 </span>  <span class="Comment"># no change</span>
<span id="L3145" class="LineNr">3145 </span>  memory-should-contain [
<span id="L3146" class="LineNr">3146 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 2</span>
<span id="L3147" class="LineNr">3147 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
<span id="L3148" class="LineNr">3148 </span>  ]
<span id="L3149" class="LineNr">3149 </span>]
<span id="L3150" class="LineNr">3150 </span>
<span id="L3151" class="LineNr">3151 </span><span class="muScenario">scenario</span> editor-combines-page-and-line-scroll [
<span id="L3152" class="LineNr">3152 </span>  <span class="Constant">local-scope</span>
<span id="L3153" class="LineNr">3153 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L3154" class="LineNr">3154 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3155" class="LineNr">3155 </span>  <span class="Comment"># initialize editor with a few pages of lines</span>
<span id="L3156" class="LineNr">3156 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3157" class="LineNr">3157 </span><span class="Constant">b</span>
<span id="L3158" class="LineNr">3158 </span><span class="Constant">c</span>
<span id="L3159" class="LineNr">3159 </span><span class="Constant">d</span>
<span id="L3160" class="LineNr">3160 </span><span class="Constant">e</span>
<span id="L3161" class="LineNr">3161 </span><span class="Constant">f</span>
<span id="L3162" class="LineNr">3162 </span><span class="Constant">g]</span>
<span id="L3163" class="LineNr">3163 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L3164" class="LineNr">3164 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3165" class="LineNr">3165 </span>  <span class="Comment"># scroll down one page and one line</span>
<span id="L3166" class="LineNr">3166 </span>  assume-console [
<span id="L3167" class="LineNr">3167 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3168" class="LineNr">3168 </span>    left-click<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
<span id="L3169" class="LineNr">3169 </span>    press down-arrow
<span id="L3170" class="LineNr">3170 </span>  ]
<span id="L3171" class="LineNr">3171 </span>  run [
<span id="L3172" class="LineNr">3172 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3173" class="LineNr">3173 </span>  ]
<span id="L3174" class="LineNr">3174 </span>  <span class="Comment"># screen scrolls down 3 lines</span>
<span id="L3175" class="LineNr">3175 </span>  screen-should-contain [
<span id="L3176" class="LineNr">3176 </span>   <span class="Constant"> .          .</span>
<span id="L3177" class="LineNr">3177 </span>   <span class="Constant"> .d         .</span>
<span id="L3178" class="LineNr">3178 </span>   <span class="Constant"> .e         .</span>
<span id="L3179" class="LineNr">3179 </span>   <span class="Constant"> .f         .</span>
<span id="L3180" class="LineNr">3180 </span>  ]
<span id="L3181" class="LineNr">3181 </span>]
<span id="L3182" class="LineNr">3182 </span>
<span id="L3183" class="LineNr">3183 </span><span class="Comment"># scroll up if necessary</span>
<span id="L3184" class="LineNr">3184 </span>
<span id="L3185" class="LineNr">3185 </span><span class="muScenario">scenario</span> editor-can-scroll-up-using-arrow-keys [
<span id="L3186" class="LineNr">3186 </span>  <span class="Constant">local-scope</span>
<span id="L3187" class="LineNr">3187 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L3188" class="LineNr">3188 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3189" class="LineNr">3189 </span>  <span class="Comment"># initialize editor with &gt;3 lines</span>
<span id="L3190" class="LineNr">3190 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3191" class="LineNr">3191 </span><span class="Constant">b</span>
<span id="L3192" class="LineNr">3192 </span><span class="Constant">c</span>
<span id="L3193" class="LineNr">3193 </span><span class="Constant">d]</span>
<span id="L3194" class="LineNr">3194 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L3195" class="LineNr">3195 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>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"> .a         .</span>
<span id="L3199" class="LineNr">3199 </span>   <span class="Constant"> .b         .</span>
<span id="L3200" class="LineNr">3200 </span>   <span class="Constant"> .c         .</span>
<span id="L3201" class="LineNr">3201 </span>  ]
<span id="L3202" class="LineNr">3202 </span>  <span class="Comment"># position cursor at top of second page, then try to move up</span>
<span id="L3203" class="LineNr">3203 </span>  assume-console [
<span id="L3204" class="LineNr">3204 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3205" class="LineNr">3205 </span>    press up-arrow
<span id="L3206" class="LineNr">3206 </span>  ]
<span id="L3207" class="LineNr">3207 </span>  run [
<span id="L3208" class="LineNr">3208 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3209" class="LineNr">3209 </span>  ]
<span id="L3210" class="LineNr">3210 </span>  <span class="Comment"># screen slides by one line</span>
<span id="L3211" class="LineNr">3211 </span>  screen-should-contain [
<span id="L3212" class="LineNr">3212 </span>   <span class="Constant"> .          .</span>
<span id="L3213" class="LineNr">3213 </span>   <span class="Constant"> .b         .</span>
<span id="L3214" class="LineNr">3214 </span>   <span class="Constant"> .c         .</span>
<span id="L3215" class="LineNr">3215 </span>   <span class="Constant"> .d         .</span>
<span id="L3216" class="LineNr">3216 </span>  ]
<span id="L3217" class="LineNr">3217 </span>]
<span id="L3218" class="LineNr">3218 </span>
<span id="L3219" class="LineNr">3219 </span><span class="muRecipe">after</span> <span class="Constant">&lt;scroll-up&gt;</span> [
<span id="L3220" class="LineNr">3220 </span>  trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[scroll up]</span>
<span id="L3221" class="LineNr">3221 </span>  top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L3222" class="LineNr">3222 </span>  old-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy top-of-screen
<span id="L3223" class="LineNr">3223 </span>  top-of-screen <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1067'>before-previous-screen-line</a> top-of-screen, editor
<span id="L3224" class="LineNr">3224 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top-of-screen
<span id="L3225" class="LineNr">3225 </span>  no-movement?:bool <span class="Special">&lt;-</span> equal old-top, top-of-screen
<span id="L3226" class="LineNr">3226 </span>  <span class="muControl">return-if</span> no-movement?,<span class="Constant"> false/don't-render</span>
<span id="L3227" class="LineNr">3227 </span>]
<span id="L3228" class="LineNr">3228 </span>
<span id="L3229" class="LineNr">3229 </span><span class="muScenario">scenario</span> editor-scrolls-up-past-wrapped-line-using-arrow-keys [
<span id="L3230" class="LineNr">3230 </span>  <span class="Constant">local-scope</span>
<span id="L3231" class="LineNr">3231 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L3232" class="LineNr">3232 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3233" class="LineNr">3233 </span>  <span class="Comment"># initialize editor with a long, wrapped line and more than a screen of</span>
<span id="L3234" class="LineNr">3234 </span>  <span class="Comment"># other lines</span>
<span id="L3235" class="LineNr">3235 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abcdef</span>
<span id="L3236" class="LineNr">3236 </span><span class="Constant">g</span>
<span id="L3237" class="LineNr">3237 </span><span class="Constant">h</span>
<span id="L3238" class="LineNr">3238 </span><span class="Constant">i]</span>
<span id="L3239" class="LineNr">3239 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L3240" class="LineNr">3240 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3241" class="LineNr">3241 </span>  screen-should-contain [
<span id="L3242" class="LineNr">3242 </span>   <span class="Constant"> .          .</span>
<span id="L3243" class="LineNr">3243 </span>   <span class="Constant"> .abcd↩     .</span>
<span id="L3244" class="LineNr">3244 </span>   <span class="Constant"> .ef        .</span>
<span id="L3245" class="LineNr">3245 </span>   <span class="Constant"> .g         .</span>
<span id="L3246" class="LineNr">3246 </span>  ]
<span id="L3247" class="LineNr">3247 </span>  <span class="Comment"># position cursor at top of second page, just below wrapped line</span>
<span id="L3248" class="LineNr">3248 </span>  assume-console [
<span id="L3249" class="LineNr">3249 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3250" class="LineNr">3250 </span>  ]
<span id="L3251" class="LineNr">3251 </span>  run [
<span id="L3252" class="LineNr">3252 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3253" class="LineNr">3253 </span>  ]
<span id="L3254" class="LineNr">3254 </span>  screen-should-contain [
<span id="L3255" class="LineNr">3255 </span>   <span class="Constant"> .          .</span>
<span id="L3256" class="LineNr">3256 </span>   <span class="Constant"> .g         .</span>
<span id="L3257" class="LineNr">3257 </span>   <span class="Constant"> .h         .</span>
<span id="L3258" class="LineNr">3258 </span>   <span class="Constant"> .i         .</span>
<span id="L3259" class="LineNr">3259 </span>  ]
<span id="L3260" class="LineNr">3260 </span>  <span class="Comment"># now move up one line</span>
<span id="L3261" class="LineNr">3261 </span>  assume-console [
<span id="L3262" class="LineNr">3262 </span>    press up-arrow
<span id="L3263" class="LineNr">3263 </span>  ]
<span id="L3264" class="LineNr">3264 </span>  run [
<span id="L3265" class="LineNr">3265 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3266" class="LineNr">3266 </span>  ]
<span id="L3267" class="LineNr">3267 </span>  <span class="Comment"># screen shows partial wrapped line</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"> .ef        .</span>
<span id="L3271" class="LineNr">3271 </span>   <span class="Constant"> .g         .</span>
<span id="L3272" class="LineNr">3272 </span>   <span class="Constant"> .h         .</span>
<span id="L3273" class="LineNr">3273 </span>  ]
<span id="L3274" class="LineNr">3274 </span>]
<span id="L3275" class="LineNr">3275 </span>
<span id="L3276" class="LineNr">3276 </span><span class="muScenario">scenario</span> editor-scrolls-up-past-wrapped-line-using-arrow-keys-2 [
<span id="L3277" class="LineNr">3277 </span>  <span class="Constant">local-scope</span>
<span id="L3278" class="LineNr">3278 </span>  <span class="Comment"># screen has 1 line for menu + 4 lines</span>
<span id="L3279" class="LineNr">3279 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L3280" class="LineNr">3280 </span>  <span class="Comment"># editor starts with a long line wrapping twice, occupying 3 of the 4 lines</span>
<span id="L3281" class="LineNr">3281 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abcdefghij</span>
<span id="L3282" class="LineNr">3282 </span><span class="Constant">k</span>
<span id="L3283" class="LineNr">3283 </span><span class="Constant">l</span>
<span id="L3284" class="LineNr">3284 </span><span class="Constant">m]</span>
<span id="L3285" class="LineNr">3285 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L3286" class="LineNr">3286 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3287" class="LineNr">3287 </span>  <span class="Comment"># position cursor at top of second page</span>
<span id="L3288" class="LineNr">3288 </span>  assume-console [
<span id="L3289" class="LineNr">3289 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3290" class="LineNr">3290 </span>  ]
<span id="L3291" class="LineNr">3291 </span>  run [
<span id="L3292" class="LineNr">3292 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3293" class="LineNr">3293 </span>  ]
<span id="L3294" class="LineNr">3294 </span>  screen-should-contain [
<span id="L3295" class="LineNr">3295 </span>   <span class="Constant"> .          .</span>
<span id="L3296" class="LineNr">3296 </span>   <span class="Constant"> .k         .</span>
<span id="L3297" class="LineNr">3297 </span>   <span class="Constant"> .l         .</span>
<span id="L3298" class="LineNr">3298 </span>   <span class="Constant"> .m         .</span>
<span id="L3299" class="LineNr">3299 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L3300" class="LineNr">3300 </span>  ]
<span id="L3301" class="LineNr">3301 </span>  <span class="Comment"># move up one line</span>
<span id="L3302" class="LineNr">3302 </span>  assume-console [
<span id="L3303" class="LineNr">3303 </span>    press up-arrow
<span id="L3304" class="LineNr">3304 </span>  ]
<span id="L3305" class="LineNr">3305 </span>  run [
<span id="L3306" class="LineNr">3306 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3307" class="LineNr">3307 </span>  ]
<span id="L3308" class="LineNr">3308 </span>  <span class="Comment"># screen shows partial wrapped line</span>
<span id="L3309" class="LineNr">3309 </span>  screen-should-contain [
<span id="L3310" class="LineNr">3310 </span>   <span class="Constant"> .          .</span>
<span id="L3311" class="LineNr">3311 </span>   <span class="Constant"> .ij        .</span>
<span id="L3312" class="LineNr">3312 </span>   <span class="Constant"> .k         .</span>
<span id="L3313" class="LineNr">3313 </span>   <span class="Constant"> .l         .</span>
<span id="L3314" class="LineNr">3314 </span>   <span class="Constant"> .m         .</span>
<span id="L3315" class="LineNr">3315 </span>  ]
<span id="L3316" class="LineNr">3316 </span>  <span class="Comment"># move up a second line</span>
<span id="L3317" class="LineNr">3317 </span>  assume-console [
<span id="L3318" class="LineNr">3318 </span>    press up-arrow
<span id="L3319" class="LineNr">3319 </span>  ]
<span id="L3320" class="LineNr">3320 </span>  run [
<span id="L3321" class="LineNr">3321 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3322" class="LineNr">3322 </span>  ]
<span id="L3323" class="LineNr">3323 </span>  <span class="Comment"># screen shows partial wrapped line</span>
<span id="L3324" class="LineNr">3324 </span>  screen-should-contain [
<span id="L3325" class="LineNr">3325 </span>   <span class="Constant"> .          .</span>
<span id="L3326" class="LineNr">3326 </span>   <span class="Constant"> .efgh↩     .</span>
<span id="L3327" class="LineNr">3327 </span>   <span class="Constant"> .ij        .</span>
<span id="L3328" class="LineNr">3328 </span>   <span class="Constant"> .k         .</span>
<span id="L3329" class="LineNr">3329 </span>   <span class="Constant"> .l         .</span>
<span id="L3330" class="LineNr">3330 </span>  ]
<span id="L3331" class="LineNr">3331 </span>  <span class="Comment"># move up a third line</span>
<span id="L3332" class="LineNr">3332 </span>  assume-console [
<span id="L3333" class="LineNr">3333 </span>    press up-arrow
<span id="L3334" class="LineNr">3334 </span>  ]
<span id="L3335" class="LineNr">3335 </span>  run [
<span id="L3336" class="LineNr">3336 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3337" class="LineNr">3337 </span>  ]
<span id="L3338" class="LineNr">3338 </span>  <span class="Comment"># screen shows partial wrapped line</span>
<span id="L3339" class="LineNr">3339 </span>  screen-should-contain [
<span id="L3340" class="LineNr">3340 </span>   <span class="Constant"> .          .</span>
<span id="L3341" class="LineNr">3341 </span>   <span class="Constant"> .abcd↩     .</span>
<span id="L3342" class="LineNr">3342 </span>   <span class="Constant"> .efgh↩     .</span>
<span id="L3343" class="LineNr">3343 </span>   <span class="Constant"> .ij        .</span>
<span id="L3344" class="LineNr">3344 </span>   <span class="Constant"> .k         .</span>
<span id="L3345" class="LineNr">3345 </span>  ]
<span id="L3346" class="LineNr">3346 </span>]
<span id="L3347" class="LineNr">3347 </span>
<span id="L3348" class="LineNr">3348 </span><span class="Comment"># same as editor-scrolls-up-past-wrapped-line-using-arrow-keys but length</span>
<span id="L3349" class="LineNr">3349 </span><span class="Comment"># slightly off, just to prevent over-training</span>
<span id="L3350" class="LineNr">3350 </span><span class="muScenario">scenario</span> editor-scrolls-up-past-wrapped-line-using-arrow-keys-3 [
<span id="L3351" class="LineNr">3351 </span>  <span class="Constant">local-scope</span>
<span id="L3352" class="LineNr">3352 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L3353" class="LineNr">3353 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3354" class="LineNr">3354 </span>  <span class="Comment"># initialize editor with a long, wrapped line and more than a screen of</span>
<span id="L3355" class="LineNr">3355 </span>  <span class="Comment"># other lines</span>
<span id="L3356" class="LineNr">3356 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[abcdef</span>
<span id="L3357" class="LineNr">3357 </span><span class="Constant">g</span>
<span id="L3358" class="LineNr">3358 </span><span class="Constant">h</span>
<span id="L3359" class="LineNr">3359 </span><span class="Constant">i]</span>
<span id="L3360" class="LineNr">3360 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">6/right</span>
<span id="L3361" class="LineNr">3361 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3362" class="LineNr">3362 </span>  screen-should-contain [
<span id="L3363" class="LineNr">3363 </span>   <span class="Constant"> .          .</span>
<span id="L3364" class="LineNr">3364 </span>   <span class="Constant"> .abcde↩    .</span>
<span id="L3365" class="LineNr">3365 </span>   <span class="Constant"> .f         .</span>
<span id="L3366" class="LineNr">3366 </span>   <span class="Constant"> .g         .</span>
<span id="L3367" class="LineNr">3367 </span>  ]
<span id="L3368" class="LineNr">3368 </span>  <span class="Comment"># position cursor at top of second page, just below wrapped line</span>
<span id="L3369" class="LineNr">3369 </span>  assume-console [
<span id="L3370" class="LineNr">3370 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3371" class="LineNr">3371 </span>  ]
<span id="L3372" class="LineNr">3372 </span>  run [
<span id="L3373" class="LineNr">3373 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3374" class="LineNr">3374 </span>  ]
<span id="L3375" class="LineNr">3375 </span>  screen-should-contain [
<span id="L3376" class="LineNr">3376 </span>   <span class="Constant"> .          .</span>
<span id="L3377" class="LineNr">3377 </span>   <span class="Constant"> .g         .</span>
<span id="L3378" class="LineNr">3378 </span>   <span class="Constant"> .h         .</span>
<span id="L3379" class="LineNr">3379 </span>   <span class="Constant"> .i         .</span>
<span id="L3380" class="LineNr">3380 </span>  ]
<span id="L3381" class="LineNr">3381 </span>  <span class="Comment"># now move up one line</span>
<span id="L3382" class="LineNr">3382 </span>  assume-console [
<span id="L3383" class="LineNr">3383 </span>    press up-arrow
<span id="L3384" class="LineNr">3384 </span>  ]
<span id="L3385" class="LineNr">3385 </span>  run [
<span id="L3386" class="LineNr">3386 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3387" class="LineNr">3387 </span>  ]
<span id="L3388" class="LineNr">3388 </span>  <span class="Comment"># screen shows partial wrapped line</span>
<span id="L3389" class="LineNr">3389 </span>  screen-should-contain [
<span id="L3390" class="LineNr">3390 </span>   <span class="Constant"> .          .</span>
<span id="L3391" class="LineNr">3391 </span>   <span class="Constant"> .f         .</span>
<span id="L3392" class="LineNr">3392 </span>   <span class="Constant"> .g         .</span>
<span id="L3393" class="LineNr">3393 </span>   <span class="Constant"> .h         .</span>
<span id="L3394" class="LineNr">3394 </span>  ]
<span id="L3395" class="LineNr">3395 </span>]
<span id="L3396" class="LineNr">3396 </span>
<span id="L3397" class="LineNr">3397 </span><span class="Comment"># check empty lines</span>
<span id="L3398" class="LineNr">3398 </span><span class="muScenario">scenario</span> editor-scrolls-up-past-wrapped-line-using-arrow-keys-4 [
<span id="L3399" class="LineNr">3399 </span>  <span class="Constant">local-scope</span>
<span id="L3400" class="LineNr">3400 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3401" class="LineNr">3401 </span>  <span class="Comment"># initialize editor with some lines around an empty line</span>
<span id="L3402" class="LineNr">3402 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3403" class="LineNr">3403 </span><span class="Constant">b</span>
<span id="L3404" class="LineNr">3404 </span>
<span id="L3405" class="LineNr">3405 </span>c
<span id="L3406" class="LineNr">3406 </span>d
<span id="L3407" class="LineNr">3407 </span>e]
<span id="L3408" class="LineNr">3408 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">6/right</span>
<span id="L3409" class="LineNr">3409 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3410" class="LineNr">3410 </span>  assume-console [
<span id="L3411" class="LineNr">3411 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3412" class="LineNr">3412 </span>  ]
<span id="L3413" class="LineNr">3413 </span>  run [
<span id="L3414" class="LineNr">3414 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3415" class="LineNr">3415 </span>  ]
<span id="L3416" class="LineNr">3416 </span>  screen-should-contain [
<span id="L3417" class="LineNr">3417 </span>   <span class="Constant"> .          .</span>
<span id="L3418" class="LineNr">3418 </span>   <span class="Constant"> .          .</span>
<span id="L3419" class="LineNr">3419 </span>   <span class="Constant"> .c         .</span>
<span id="L3420" class="LineNr">3420 </span>   <span class="Constant"> .d         .</span>
<span id="L3421" class="LineNr">3421 </span>  ]
<span id="L3422" class="LineNr">3422 </span>  assume-console [
<span id="L3423" class="LineNr">3423 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3424" class="LineNr">3424 </span>  ]
<span id="L3425" class="LineNr">3425 </span>  run [
<span id="L3426" class="LineNr">3426 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3427" class="LineNr">3427 </span>  ]
<span id="L3428" class="LineNr">3428 </span>  screen-should-contain [
<span id="L3429" class="LineNr">3429 </span>   <span class="Constant"> .          .</span>
<span id="L3430" class="LineNr">3430 </span>   <span class="Constant"> .d         .</span>
<span id="L3431" class="LineNr">3431 </span>   <span class="Constant"> .e         .</span>
<span id="L3432" class="LineNr">3432 </span>   <span class="Constant"> .╌╌╌╌╌╌    .</span>
<span id="L3433" class="LineNr">3433 </span>  ]
<span id="L3434" class="LineNr">3434 </span>  assume-console [
<span id="L3435" class="LineNr">3435 </span>    press <a href='003-shortcuts.mu.html#L3833'>page-up</a>
<span id="L3436" class="LineNr">3436 </span>  ]
<span id="L3437" class="LineNr">3437 </span>  run [
<span id="L3438" class="LineNr">3438 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3439" class="LineNr">3439 </span>  ]
<span id="L3440" class="LineNr">3440 </span>  screen-should-contain [
<span id="L3441" class="LineNr">3441 </span>   <span class="Constant"> .          .</span>
<span id="L3442" class="LineNr">3442 </span>   <span class="Constant"> .          .</span>
<span id="L3443" class="LineNr">3443 </span>   <span class="Constant"> .c         .</span>
<span id="L3444" class="LineNr">3444 </span>   <span class="Constant"> .d         .</span>
<span id="L3445" class="LineNr">3445 </span>  ]
<span id="L3446" class="LineNr">3446 </span>]
<span id="L3447" class="LineNr">3447 </span>
<span id="L3448" class="LineNr">3448 </span><span class="muScenario">scenario</span> editor-scrolls-up-on-left-arrow [
<span id="L3449" class="LineNr">3449 </span>  <span class="Constant">local-scope</span>
<span id="L3450" class="LineNr">3450 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L3451" class="LineNr">3451 </span>  assume-screen <span class="Constant">5/width</span>, <span class="Constant">4/height</span>
<span id="L3452" class="LineNr">3452 </span>  <span class="Comment"># editor contains &gt;3 lines</span>
<span id="L3453" class="LineNr">3453 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3454" class="LineNr">3454 </span><span class="Constant">b</span>
<span id="L3455" class="LineNr">3455 </span><span class="Constant">c</span>
<span id="L3456" class="LineNr">3456 </span><span class="Constant">d</span>
<span id="L3457" class="LineNr">3457 </span><span class="Constant">e]</span>
<span id="L3458" class="LineNr">3458 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L3459" class="LineNr">3459 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3460" class="LineNr">3460 </span>  <span class="Comment"># position cursor at top of second page</span>
<span id="L3461" class="LineNr">3461 </span>  assume-console [
<span id="L3462" class="LineNr">3462 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3463" class="LineNr">3463 </span>  ]
<span id="L3464" class="LineNr">3464 </span>  run [
<span id="L3465" class="LineNr">3465 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3466" class="LineNr">3466 </span>  ]
<span id="L3467" class="LineNr">3467 </span>  screen-should-contain [
<span id="L3468" class="LineNr">3468 </span>   <span class="Constant"> .     .</span>
<span id="L3469" class="LineNr">3469 </span>   <span class="Constant"> .c    .</span>
<span id="L3470" class="LineNr">3470 </span>   <span class="Constant"> .d    .</span>
<span id="L3471" class="LineNr">3471 </span>   <span class="Constant"> .e    .</span>
<span id="L3472" class="LineNr">3472 </span>  ]
<span id="L3473" class="LineNr">3473 </span>  <span class="Comment"># now try to move left</span>
<span id="L3474" class="LineNr">3474 </span>  assume-console [
<span id="L3475" class="LineNr">3475 </span>    press left-arrow
<span id="L3476" class="LineNr">3476 </span>  ]
<span id="L3477" class="LineNr">3477 </span>  run [
<span id="L3478" class="LineNr">3478 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3479" class="LineNr">3479 </span>    3:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L3480" class="LineNr">3480 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L3481" class="LineNr">3481 </span>  ]
<span id="L3482" class="LineNr">3482 </span>  <span class="Comment"># screen scrolls</span>
<span id="L3483" class="LineNr">3483 </span>  screen-should-contain [
<span id="L3484" class="LineNr">3484 </span>   <span class="Constant"> .     .</span>
<span id="L3485" class="LineNr">3485 </span>   <span class="Constant"> .b    .</span>
<span id="L3486" class="LineNr">3486 </span>   <span class="Constant"> .c    .</span>
<span id="L3487" class="LineNr">3487 </span>   <span class="Constant"> .d    .</span>
<span id="L3488" class="LineNr">3488 </span>  ]
<span id="L3489" class="LineNr">3489 </span>  memory-should-contain [
<span id="L3490" class="LineNr">3490 </span>   <span class="Constant"> 3</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L3491" class="LineNr">3491 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L3492" class="LineNr">3492 </span>  ]
<span id="L3493" class="LineNr">3493 </span>]
<span id="L3494" class="LineNr">3494 </span>
<span id="L3495" class="LineNr">3495 </span><span class="muScenario">scenario</span> editor-can-scroll-up-to-start-of-file [
<span id="L3496" class="LineNr">3496 </span>  <span class="Constant">local-scope</span>
<span id="L3497" class="LineNr">3497 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L3498" class="LineNr">3498 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3499" class="LineNr">3499 </span>  <span class="Comment"># initialize editor with &gt;3 lines</span>
<span id="L3500" class="LineNr">3500 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3501" class="LineNr">3501 </span><span class="Constant">b</span>
<span id="L3502" class="LineNr">3502 </span><span class="Constant">c</span>
<span id="L3503" class="LineNr">3503 </span><span class="Constant">d]</span>
<span id="L3504" class="LineNr">3504 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L3505" class="LineNr">3505 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3506" class="LineNr">3506 </span>  screen-should-contain [
<span id="L3507" class="LineNr">3507 </span>   <span class="Constant"> .          .</span>
<span id="L3508" class="LineNr">3508 </span>   <span class="Constant"> .a         .</span>
<span id="L3509" class="LineNr">3509 </span>   <span class="Constant"> .b         .</span>
<span id="L3510" class="LineNr">3510 </span>   <span class="Constant"> .c         .</span>
<span id="L3511" class="LineNr">3511 </span>  ]
<span id="L3512" class="LineNr">3512 </span>  <span class="Comment"># position cursor at top of second page, then try to move up to start of</span>
<span id="L3513" class="LineNr">3513 </span>  <span class="Comment"># text</span>
<span id="L3514" class="LineNr">3514 </span>  assume-console [
<span id="L3515" class="LineNr">3515 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3516" class="LineNr">3516 </span>    press up-arrow
<span id="L3517" class="LineNr">3517 </span>    press up-arrow
<span id="L3518" class="LineNr">3518 </span>  ]
<span id="L3519" class="LineNr">3519 </span>  run [
<span id="L3520" class="LineNr">3520 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3521" class="LineNr">3521 </span>  ]
<span id="L3522" class="LineNr">3522 </span>  <span class="Comment"># screen slides by one line</span>
<span id="L3523" class="LineNr">3523 </span>  screen-should-contain [
<span id="L3524" class="LineNr">3524 </span>   <span class="Constant"> .          .</span>
<span id="L3525" class="LineNr">3525 </span>   <span class="Constant"> .a         .</span>
<span id="L3526" class="LineNr">3526 </span>   <span class="Constant"> .b         .</span>
<span id="L3527" class="LineNr">3527 </span>   <span class="Constant"> .c         .</span>
<span id="L3528" class="LineNr">3528 </span>  ]
<span id="L3529" class="LineNr">3529 </span>  <span class="Comment"># try to move up again</span>
<span id="L3530" class="LineNr">3530 </span>  assume-console [
<span id="L3531" class="LineNr">3531 </span>    press up-arrow
<span id="L3532" class="LineNr">3532 </span>  ]
<span id="L3533" class="LineNr">3533 </span>  run [
<span id="L3534" class="LineNr">3534 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3535" class="LineNr">3535 </span>  ]
<span id="L3536" class="LineNr">3536 </span>  <span class="Comment"># screen remains unchanged</span>
<span id="L3537" class="LineNr">3537 </span>  screen-should-contain [
<span id="L3538" class="LineNr">3538 </span>   <span class="Constant"> .          .</span>
<span id="L3539" class="LineNr">3539 </span>   <span class="Constant"> .a         .</span>
<span id="L3540" class="LineNr">3540 </span>   <span class="Constant"> .b         .</span>
<span id="L3541" class="LineNr">3541 </span>   <span class="Constant"> .c         .</span>
<span id="L3542" class="LineNr">3542 </span>  ]
<span id="L3543" class="LineNr">3543 </span>]
<span id="L3544" class="LineNr">3544 </span>
<span id="L3545" class="LineNr">3545 </span><span class="Comment"># ctrl-f/page-down - render next page if it exists</span>
<span id="L3546" class="LineNr">3546 </span>
<span id="L3547" class="LineNr">3547 </span><span class="muScenario">scenario</span> editor-can-scroll [
<span id="L3548" class="LineNr">3548 </span>  <span class="Constant">local-scope</span>
<span id="L3549" class="LineNr">3549 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3550" class="LineNr">3550 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3551" class="LineNr">3551 </span><span class="Constant">b</span>
<span id="L3552" class="LineNr">3552 </span><span class="Constant">c</span>
<span id="L3553" class="LineNr">3553 </span><span class="Constant">d]</span>
<span id="L3554" class="LineNr">3554 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L3555" class="LineNr">3555 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3556" class="LineNr">3556 </span>  screen-should-contain [
<span id="L3557" class="LineNr">3557 </span>   <span class="Constant"> .          .</span>
<span id="L3558" class="LineNr">3558 </span>   <span class="Constant"> .a         .</span>
<span id="L3559" class="LineNr">3559 </span>   <span class="Constant"> .b         .</span>
<span id="L3560" class="LineNr">3560 </span>   <span class="Constant"> .c         .</span>
<span id="L3561" class="LineNr">3561 </span>  ]
<span id="L3562" class="LineNr">3562 </span>  <span class="Comment"># scroll down</span>
<span id="L3563" class="LineNr">3563 </span>  assume-console [
<span id="L3564" class="LineNr">3564 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3565" class="LineNr">3565 </span>  ]
<span id="L3566" class="LineNr">3566 </span>  run [
<span id="L3567" class="LineNr">3567 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3568" class="LineNr">3568 </span>  ]
<span id="L3569" class="LineNr">3569 </span>  <span class="Comment"># screen shows next page</span>
<span id="L3570" class="LineNr">3570 </span>  screen-should-contain [
<span id="L3571" class="LineNr">3571 </span>   <span class="Constant"> .          .</span>
<span id="L3572" class="LineNr">3572 </span>   <span class="Constant"> .c         .</span>
<span id="L3573" class="LineNr">3573 </span>   <span class="Constant"> .d         .</span>
<span id="L3574" class="LineNr">3574 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L3575" class="LineNr">3575 </span>  ]
<span id="L3576" class="LineNr">3576 </span>]
<span id="L3577" class="LineNr">3577 </span>
<span id="L3578" class="LineNr">3578 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L3579" class="LineNr">3579 </span>  <span class="Delimiter">{</span>
<span id="L3580" class="LineNr">3580 </span>    page-down?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">6/ctrl-f</span>
<span id="L3581" class="LineNr">3581 </span>    <span class="muControl">break-unless</span> page-down?
<span id="L3582" class="LineNr">3582 </span>    old-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L3583" class="LineNr">3583 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L3584" class="LineNr">3584 </span>    <a href='003-shortcuts.mu.html#L3610'>page-down</a> editor
<span id="L3585" class="LineNr">3585 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
<span id="L3586" class="LineNr">3586 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L3587" class="LineNr">3587 </span>    top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L3588" class="LineNr">3588 </span>    movement?:bool <span class="Special">&lt;-</span> not-equal top-of-screen, old-top
<span id="L3589" class="LineNr">3589 </span>   <span class="muControl"> return</span> movement?/go-render
<span id="L3590" class="LineNr">3590 </span>  <span class="Delimiter">}</span>
<span id="L3591" class="LineNr">3591 </span>]
<span id="L3592" class="LineNr">3592 </span>
<span id="L3593" class="LineNr">3593 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L199'>&lt;handle-special-key&gt;</a></span> [
<span id="L3594" class="LineNr">3594 </span>  <span class="Delimiter">{</span>
<span id="L3595" class="LineNr">3595 </span>    page-down?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65518/page-down</span>
<span id="L3596" class="LineNr">3596 </span>    <span class="muControl">break-unless</span> page-down?
<span id="L3597" class="LineNr">3597 </span>    old-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L3598" class="LineNr">3598 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L3599" class="LineNr">3599 </span>    <a href='003-shortcuts.mu.html#L3610'>page-down</a> editor
<span id="L3600" class="LineNr">3600 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
<span id="L3601" class="LineNr">3601 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L3602" class="LineNr">3602 </span>    top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L3603" class="LineNr">3603 </span>    movement?:bool <span class="Special">&lt;-</span> not-equal top-of-screen, old-top
<span id="L3604" class="LineNr">3604 </span>   <span class="muControl"> return</span> movement?/go-render
<span id="L3605" class="LineNr">3605 </span>  <span class="Delimiter">}</span>
<span id="L3606" class="LineNr">3606 </span>]
<span id="L3607" class="LineNr">3607 </span>
<span id="L3608" class="LineNr">3608 </span><span class="Comment"># page-down skips entire wrapped lines, so it can't scroll past lines</span>
<span id="L3609" class="LineNr">3609 </span><span class="Comment"># taking up the entire screen</span>
<span id="L3610" class="LineNr">3610 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L3610'>page-down</a> editor:&amp;:editor<span class="muRecipe"> -&gt; </span>editor:&amp;:editor [
<span id="L3611" class="LineNr">3611 </span>  <span class="Constant">local-scope</span>
<span id="L3612" class="LineNr">3612 </span>  <span class="Constant">load-inputs</span>
<span id="L3613" class="LineNr">3613 </span>  <span class="Comment"># if editor contents don't overflow screen, do nothing</span>
<span id="L3614" class="LineNr">3614 </span>  bottom-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">bottom-of-screen:offset</span>
<span id="L3615" class="LineNr">3615 </span>  <span class="muControl">return-unless</span> bottom-of-screen
<span id="L3616" class="LineNr">3616 </span>  <span class="Comment"># if not, position cursor at final character</span>
<span id="L3617" class="LineNr">3617 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L3618" class="LineNr">3618 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L38'>prev</a> bottom-of-screen
<span id="L3619" class="LineNr">3619 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L3620" class="LineNr">3620 </span>  <span class="Comment"># keep one line in common with previous page</span>
<span id="L3621" class="LineNr">3621 </span>  <span class="Delimiter">{</span>
<span id="L3622" class="LineNr">3622 </span>    <a href='../065duplex_list.mu.html#L629'>last</a>:char <span class="Special">&lt;-</span> get *before-cursor, <span class="Constant">value:offset</span>
<span id="L3623" class="LineNr">3623 </span>    newline?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L629'>last</a>, <span class="Constant">10/newline</span>
<span id="L3624" class="LineNr">3624 </span>    <span class="muControl">break-unless</span> newline?:bool
<span id="L3625" class="LineNr">3625 </span>    before-cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L38'>prev</a> before-cursor
<span id="L3626" class="LineNr">3626 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L3627" class="LineNr">3627 </span>  <span class="Delimiter">}</span>
<span id="L3628" class="LineNr">3628 </span>  <span class="Comment"># move cursor and top-of-screen to start of that line</span>
<span id="L3629" class="LineNr">3629 </span>  <a href='003-shortcuts.mu.html#L3635'>move-to-start-of-line</a> editor
<span id="L3630" class="LineNr">3630 </span>  before-cursor <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L3631" class="LineNr">3631 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, before-cursor
<span id="L3632" class="LineNr">3632 </span>]
<span id="L3633" class="LineNr">3633 </span>
<span id="L3634" class="LineNr">3634 </span><span class="Comment"># jump to previous newline</span>
<span id="L3635" class="LineNr">3635 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L3635'>move-to-start-of-line</a> editor:&amp;:editor<span class="muRecipe"> -&gt; </span>editor:&amp;:editor [
<span id="L3636" class="LineNr">3636 </span>  <span class="Constant">local-scope</span>
<span id="L3637" class="LineNr">3637 </span>  <span class="Constant">load-inputs</span>
<span id="L3638" class="LineNr">3638 </span>  <span class="Comment"># update cursor column</span>
<span id="L3639" class="LineNr">3639 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L3640" class="LineNr">3640 </span>  cursor-column:num <span class="Special">&lt;-</span> copy left
<span id="L3641" class="LineNr">3641 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L3642" class="LineNr">3642 </span>  <span class="Comment"># update before-cursor</span>
<span id="L3643" class="LineNr">3643 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L3644" class="LineNr">3644 </span>  init:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
<span id="L3645" class="LineNr">3645 </span>  <span class="Comment"># while not at start of line, move</span>
<span id="L3646" class="LineNr">3646 </span>  <span class="Delimiter">{</span>
<span id="L3647" class="LineNr">3647 </span>    at-start-of-text?:bool <span class="Special">&lt;-</span> equal before-cursor, init
<span id="L3648" class="LineNr">3648 </span>    <span class="muControl">break-if</span> at-start-of-text?
<span id="L3649" class="LineNr">3649 </span>    <a href='../065duplex_list.mu.html#L38'>prev</a>:char <span class="Special">&lt;-</span> get *before-cursor, <span class="Constant">value:offset</span>
<span id="L3650" class="LineNr">3650 </span>    at-start-of-line?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L38'>prev</a>, <span class="Constant">10/newline</span>
<span id="L3651" class="LineNr">3651 </span>    <span class="muControl">break-if</span> at-start-of-line?
<span id="L3652" class="LineNr">3652 </span>    before-cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L38'>prev</a> before-cursor
<span id="L3653" class="LineNr">3653 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
<span id="L3654" class="LineNr">3654 </span>    assert before-cursor, <span class="Constant">[move-to-start-of-line tried to move before start of text]</span>
<span id="L3655" class="LineNr">3655 </span>   <span class="muControl"> loop</span>
<span id="L3656" class="LineNr">3656 </span>  <span class="Delimiter">}</span>
<span id="L3657" class="LineNr">3657 </span>]
<span id="L3658" class="LineNr">3658 </span>
<span id="L3659" class="LineNr">3659 </span><span class="muScenario">scenario</span> editor-does-not-scroll-past-end [
<span id="L3660" class="LineNr">3660 </span>  <span class="Constant">local-scope</span>
<span id="L3661" class="LineNr">3661 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3662" class="LineNr">3662 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3663" class="LineNr">3663 </span><span class="Constant">b]</span>
<span id="L3664" class="LineNr">3664 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L3665" class="LineNr">3665 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3666" class="LineNr">3666 </span>  screen-should-contain [
<span id="L3667" class="LineNr">3667 </span>   <span class="Constant"> .          .</span>
<span id="L3668" class="LineNr">3668 </span>   <span class="Constant"> .a         .</span>
<span id="L3669" class="LineNr">3669 </span>   <span class="Constant"> .b         .</span>
<span id="L3670" class="LineNr">3670 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L3671" class="LineNr">3671 </span>  ]
<span id="L3672" class="LineNr">3672 </span>  <span class="Comment"># scroll down</span>
<span id="L3673" class="LineNr">3673 </span>  assume-console [
<span id="L3674" class="LineNr">3674 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3675" class="LineNr">3675 </span>  ]
<span id="L3676" class="LineNr">3676 </span>  run [
<span id="L3677" class="LineNr">3677 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3678" class="LineNr">3678 </span>  ]
<span id="L3679" class="LineNr">3679 </span>  <span class="Comment"># screen remains unmodified</span>
<span id="L3680" class="LineNr">3680 </span>  screen-should-contain [
<span id="L3681" class="LineNr">3681 </span>   <span class="Constant"> .          .</span>
<span id="L3682" class="LineNr">3682 </span>   <span class="Constant"> .a         .</span>
<span id="L3683" class="LineNr">3683 </span>   <span class="Constant"> .b         .</span>
<span id="L3684" class="LineNr">3684 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L3685" class="LineNr">3685 </span>  ]
<span id="L3686" class="LineNr">3686 </span>]
<span id="L3687" class="LineNr">3687 </span>
<span id="L3688" class="LineNr">3688 </span><span class="muScenario">scenario</span> editor-starts-next-page-at-start-of-wrapped-line [
<span id="L3689" class="LineNr">3689 </span>  <span class="Constant">local-scope</span>
<span id="L3690" class="LineNr">3690 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines for text</span>
<span id="L3691" class="LineNr">3691 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3692" class="LineNr">3692 </span>  <span class="Comment"># editor contains a long last line</span>
<span id="L3693" class="LineNr">3693 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3694" class="LineNr">3694 </span><span class="Constant">b</span>
<span id="L3695" class="LineNr">3695 </span><span class="Constant">cdefgh]</span>
<span id="L3696" class="LineNr">3696 </span>  <span class="Comment"># editor screen triggers wrap of last line</span>
<span id="L3697" class="LineNr">3697 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">4/right</span>
<span id="L3698" class="LineNr">3698 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3699" class="LineNr">3699 </span>  <span class="Comment"># some part of last line is not displayed</span>
<span id="L3700" class="LineNr">3700 </span>  screen-should-contain [
<span id="L3701" class="LineNr">3701 </span>   <span class="Constant"> .          .</span>
<span id="L3702" class="LineNr">3702 </span>   <span class="Constant"> .a         .</span>
<span id="L3703" class="LineNr">3703 </span>   <span class="Constant"> .b         .</span>
<span id="L3704" class="LineNr">3704 </span>   <span class="Constant"> .cde↩      .</span>
<span id="L3705" class="LineNr">3705 </span>  ]
<span id="L3706" class="LineNr">3706 </span>  <span class="Comment"># scroll down</span>
<span id="L3707" class="LineNr">3707 </span>  assume-console [
<span id="L3708" class="LineNr">3708 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3709" class="LineNr">3709 </span>  ]
<span id="L3710" class="LineNr">3710 </span>  run [
<span id="L3711" class="LineNr">3711 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3712" class="LineNr">3712 </span>  ]
<span id="L3713" class="LineNr">3713 </span>  <span class="Comment"># screen shows entire wrapped line</span>
<span id="L3714" class="LineNr">3714 </span>  screen-should-contain [
<span id="L3715" class="LineNr">3715 </span>   <span class="Constant"> .          .</span>
<span id="L3716" class="LineNr">3716 </span>   <span class="Constant"> .cde↩      .</span>
<span id="L3717" class="LineNr">3717 </span>   <span class="Constant"> .fgh       .</span>
<span id="L3718" class="LineNr">3718 </span>   <span class="Constant"> .╌╌╌╌      .</span>
<span id="L3719" class="LineNr">3719 </span>  ]
<span id="L3720" class="LineNr">3720 </span>]
<span id="L3721" class="LineNr">3721 </span>
<span id="L3722" class="LineNr">3722 </span><span class="muScenario">scenario</span> editor-starts-next-page-at-start-of-wrapped-line-2 [
<span id="L3723" class="LineNr">3723 </span>  <span class="Constant">local-scope</span>
<span id="L3724" class="LineNr">3724 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines for text</span>
<span id="L3725" class="LineNr">3725 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3726" class="LineNr">3726 </span>  <span class="Comment"># editor contains a very long line that occupies last two lines of screen</span>
<span id="L3727" class="LineNr">3727 </span>  <span class="Comment"># and still has something left over</span>
<span id="L3728" class="LineNr">3728 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3729" class="LineNr">3729 </span><span class="Constant">bcdefgh]</span>
<span id="L3730" class="LineNr">3730 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">4/right</span>
<span id="L3731" class="LineNr">3731 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3732" class="LineNr">3732 </span>  <span class="Comment"># some part of last line is not displayed</span>
<span id="L3733" class="LineNr">3733 </span>  screen-should-contain [
<span id="L3734" class="LineNr">3734 </span>   <span class="Constant"> .          .</span>
<span id="L3735" class="LineNr">3735 </span>   <span class="Constant"> .a         .</span>
<span id="L3736" class="LineNr">3736 </span>   <span class="Constant"> .bcd↩      .</span>
<span id="L3737" class="LineNr">3737 </span>   <span class="Constant"> .efg↩      .</span>
<span id="L3738" class="LineNr">3738 </span>  ]
<span id="L3739" class="LineNr">3739 </span>  <span class="Comment"># scroll down</span>
<span id="L3740" class="LineNr">3740 </span>  assume-console [
<span id="L3741" class="LineNr">3741 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3742" class="LineNr">3742 </span>  ]
<span id="L3743" class="LineNr">3743 </span>  run [
<span id="L3744" class="LineNr">3744 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3745" class="LineNr">3745 </span>  ]
<span id="L3746" class="LineNr">3746 </span>  <span class="Comment"># screen shows entire wrapped line</span>
<span id="L3747" class="LineNr">3747 </span>  screen-should-contain [
<span id="L3748" class="LineNr">3748 </span>   <span class="Constant"> .          .</span>
<span id="L3749" class="LineNr">3749 </span>   <span class="Constant"> .bcd↩      .</span>
<span id="L3750" class="LineNr">3750 </span>   <span class="Constant"> .efg↩      .</span>
<span id="L3751" class="LineNr">3751 </span>   <span class="Constant"> .h         .</span>
<span id="L3752" class="LineNr">3752 </span>  ]
<span id="L3753" class="LineNr">3753 </span>]
<span id="L3754" class="LineNr">3754 </span>
<span id="L3755" class="LineNr">3755 </span><span class="Comment"># ctrl-b/page-up - render previous page if it exists</span>
<span id="L3756" class="LineNr">3756 </span>
<span id="L3757" class="LineNr">3757 </span><span class="muScenario">scenario</span> editor-can-scroll-up [
<span id="L3758" class="LineNr">3758 </span>  <span class="Constant">local-scope</span>
<span id="L3759" class="LineNr">3759 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3760" class="LineNr">3760 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3761" class="LineNr">3761 </span><span class="Constant">b</span>
<span id="L3762" class="LineNr">3762 </span><span class="Constant">c</span>
<span id="L3763" class="LineNr">3763 </span><span class="Constant">d]</span>
<span id="L3764" class="LineNr">3764 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L3765" class="LineNr">3765 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3766" class="LineNr">3766 </span>  screen-should-contain [
<span id="L3767" class="LineNr">3767 </span>   <span class="Constant"> .          .</span>
<span id="L3768" class="LineNr">3768 </span>   <span class="Constant"> .a         .</span>
<span id="L3769" class="LineNr">3769 </span>   <span class="Constant"> .b         .</span>
<span id="L3770" class="LineNr">3770 </span>   <span class="Constant"> .c         .</span>
<span id="L3771" class="LineNr">3771 </span>  ]
<span id="L3772" class="LineNr">3772 </span>  <span class="Comment"># scroll down</span>
<span id="L3773" class="LineNr">3773 </span>  assume-console [
<span id="L3774" class="LineNr">3774 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3775" class="LineNr">3775 </span>  ]
<span id="L3776" class="LineNr">3776 </span>  run [
<span id="L3777" class="LineNr">3777 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3778" class="LineNr">3778 </span>  ]
<span id="L3779" class="LineNr">3779 </span>  <span class="Comment"># screen shows next page</span>
<span id="L3780" class="LineNr">3780 </span>  screen-should-contain [
<span id="L3781" class="LineNr">3781 </span>   <span class="Constant"> .          .</span>
<span id="L3782" class="LineNr">3782 </span>   <span class="Constant"> .c         .</span>
<span id="L3783" class="LineNr">3783 </span>   <span class="Constant"> .d         .</span>
<span id="L3784" class="LineNr">3784 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L3785" class="LineNr">3785 </span>  ]
<span id="L3786" class="LineNr">3786 </span>  <span class="Comment"># scroll back up</span>
<span id="L3787" class="LineNr">3787 </span>  assume-console [
<span id="L3788" class="LineNr">3788 </span>    press <a href='003-shortcuts.mu.html#L3833'>page-up</a>
<span id="L3789" class="LineNr">3789 </span>  ]
<span id="L3790" class="LineNr">3790 </span>  run [
<span id="L3791" class="LineNr">3791 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3792" class="LineNr">3792 </span>  ]
<span id="L3793" class="LineNr">3793 </span>  <span class="Comment"># screen shows original page again</span>
<span id="L3794" class="LineNr">3794 </span>  screen-should-contain [
<span id="L3795" class="LineNr">3795 </span>   <span class="Constant"> .          .</span>
<span id="L3796" class="LineNr">3796 </span>   <span class="Constant"> .a         .</span>
<span id="L3797" class="LineNr">3797 </span>   <span class="Constant"> .b         .</span>
<span id="L3798" class="LineNr">3798 </span>   <span class="Constant"> .c         .</span>
<span id="L3799" class="LineNr">3799 </span>  ]
<span id="L3800" class="LineNr">3800 </span>]
<span id="L3801" class="LineNr">3801 </span>
<span id="L3802" class="LineNr">3802 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L3803" class="LineNr">3803 </span>  <span class="Delimiter">{</span>
<span id="L3804" class="LineNr">3804 </span>    page-up?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">2/ctrl-b</span>
<span id="L3805" class="LineNr">3805 </span>    <span class="muControl">break-unless</span> page-up?
<span id="L3806" class="LineNr">3806 </span>    old-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L3807" class="LineNr">3807 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L3808" class="LineNr">3808 </span>    editor <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L3833'>page-up</a> editor, <a href='../081print.mu.html#L782'>screen-height</a>
<span id="L3809" class="LineNr">3809 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
<span id="L3810" class="LineNr">3810 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L3811" class="LineNr">3811 </span>    top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L3812" class="LineNr">3812 </span>    movement?:bool <span class="Special">&lt;-</span> not-equal top-of-screen, old-top
<span id="L3813" class="LineNr">3813 </span>   <span class="muControl"> return</span> movement?/go-render
<span id="L3814" class="LineNr">3814 </span>  <span class="Delimiter">}</span>
<span id="L3815" class="LineNr">3815 </span>]
<span id="L3816" class="LineNr">3816 </span>
<span id="L3817" class="LineNr">3817 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L199'>&lt;handle-special-key&gt;</a></span> [
<span id="L3818" class="LineNr">3818 </span>  <span class="Delimiter">{</span>
<span id="L3819" class="LineNr">3819 </span>    page-up?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65519/page-up</span>
<span id="L3820" class="LineNr">3820 </span>    <span class="muControl">break-unless</span> page-up?
<span id="L3821" class="LineNr">3821 </span>    old-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L3822" class="LineNr">3822 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L3823" class="LineNr">3823 </span>    editor <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L3833'>page-up</a> editor, <a href='../081print.mu.html#L782'>screen-height</a>
<span id="L3824" class="LineNr">3824 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
<span id="L3825" class="LineNr">3825 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L3826" class="LineNr">3826 </span>    top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L3827" class="LineNr">3827 </span>    movement?:bool <span class="Special">&lt;-</span> not-equal top-of-screen, old-top
<span id="L3828" class="LineNr">3828 </span>    <span class="Comment"># don't bother re-rendering if nothing changed. todo: test this</span>
<span id="L3829" class="LineNr">3829 </span>   <span class="muControl"> return</span> movement?/go-render
<span id="L3830" class="LineNr">3830 </span>  <span class="Delimiter">}</span>
<span id="L3831" class="LineNr">3831 </span>]
<span id="L3832" class="LineNr">3832 </span>
<span id="L3833" class="LineNr">3833 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L3833'>page-up</a> editor:&amp;:editor, <a href='../081print.mu.html#L782'>screen-height</a>:num<span class="muRecipe"> -&gt; </span>editor:&amp;:editor [
<span id="L3834" class="LineNr">3834 </span>  <span class="Constant">local-scope</span>
<span id="L3835" class="LineNr">3835 </span>  <span class="Constant">load-inputs</span>
<span id="L3836" class="LineNr">3836 </span>  max:num <span class="Special">&lt;-</span> subtract <a href='../081print.mu.html#L782'>screen-height</a>, <span class="Constant">1/menu-bar</span>, <span class="Constant">1/overlapping-line</span>
<span id="L3837" class="LineNr">3837 </span>  count:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
<span id="L3838" class="LineNr">3838 </span>  top-of-screen:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L3839" class="LineNr">3839 </span>  <span class="Delimiter">{</span>
<span id="L3840" class="LineNr">3840 </span>    done?:bool <span class="Special">&lt;-</span> greater-or-equal count, max
<span id="L3841" class="LineNr">3841 </span>    <span class="muControl">break-if</span> done?
<span id="L3842" class="LineNr">3842 </span>    <a href='../065duplex_list.mu.html#L38'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1067'>before-previous-screen-line</a> top-of-screen, editor
<span id="L3843" class="LineNr">3843 </span>    <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L38'>prev</a>
<span id="L3844" class="LineNr">3844 </span>    top-of-screen <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L38'>prev</a>
<span id="L3845" class="LineNr">3845 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top-of-screen
<span id="L3846" class="LineNr">3846 </span>    count <span class="Special">&lt;-</span> add count,<span class="Constant"> 1</span>
<span id="L3847" class="LineNr">3847 </span>   <span class="muControl"> loop</span>
<span id="L3848" class="LineNr">3848 </span>  <span class="Delimiter">}</span>
<span id="L3849" class="LineNr">3849 </span>]
<span id="L3850" class="LineNr">3850 </span>
<span id="L3851" class="LineNr">3851 </span><span class="muScenario">scenario</span> editor-can-scroll-up-multiple-pages [
<span id="L3852" class="LineNr">3852 </span>  <span class="Constant">local-scope</span>
<span id="L3853" class="LineNr">3853 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines</span>
<span id="L3854" class="LineNr">3854 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3855" class="LineNr">3855 </span>  <span class="Comment"># initialize editor with 8 lines</span>
<span id="L3856" class="LineNr">3856 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3857" class="LineNr">3857 </span><span class="Constant">b</span>
<span id="L3858" class="LineNr">3858 </span><span class="Constant">c</span>
<span id="L3859" class="LineNr">3859 </span><span class="Constant">d</span>
<span id="L3860" class="LineNr">3860 </span><span class="Constant">e</span>
<span id="L3861" class="LineNr">3861 </span><span class="Constant">f</span>
<span id="L3862" class="LineNr">3862 </span><span class="Constant">g</span>
<span id="L3863" class="LineNr">3863 </span><span class="Constant">h]</span>
<span id="L3864" class="LineNr">3864 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L3865" class="LineNr">3865 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3866" class="LineNr">3866 </span>  screen-should-contain [
<span id="L3867" class="LineNr">3867 </span>   <span class="Constant"> .          .</span>
<span id="L3868" class="LineNr">3868 </span>   <span class="Constant"> .a         .</span>
<span id="L3869" class="LineNr">3869 </span>   <span class="Constant"> .b         .</span>
<span id="L3870" class="LineNr">3870 </span>   <span class="Constant"> .c         .</span>
<span id="L3871" class="LineNr">3871 </span>  ]
<span id="L3872" class="LineNr">3872 </span>  <span class="Comment"># scroll down two pages</span>
<span id="L3873" class="LineNr">3873 </span>  assume-console [
<span id="L3874" class="LineNr">3874 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3875" class="LineNr">3875 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3876" class="LineNr">3876 </span>  ]
<span id="L3877" class="LineNr">3877 </span>  run [
<span id="L3878" class="LineNr">3878 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3879" class="LineNr">3879 </span>  ]
<span id="L3880" class="LineNr">3880 </span>  <span class="Comment"># screen shows third page</span>
<span id="L3881" class="LineNr">3881 </span>  screen-should-contain [
<span id="L3882" class="LineNr">3882 </span>   <span class="Constant"> .          .</span>
<span id="L3883" class="LineNr">3883 </span>   <span class="Constant"> .e         .</span>
<span id="L3884" class="LineNr">3884 </span>   <span class="Constant"> .f         .</span>
<span id="L3885" class="LineNr">3885 </span>   <span class="Constant"> .g         .</span>
<span id="L3886" class="LineNr">3886 </span>  ]
<span id="L3887" class="LineNr">3887 </span>  <span class="Comment"># scroll up</span>
<span id="L3888" class="LineNr">3888 </span>  assume-console [
<span id="L3889" class="LineNr">3889 </span>    press <a href='003-shortcuts.mu.html#L3833'>page-up</a>
<span id="L3890" class="LineNr">3890 </span>  ]
<span id="L3891" class="LineNr">3891 </span>  run [
<span id="L3892" class="LineNr">3892 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3893" class="LineNr">3893 </span>  ]
<span id="L3894" class="LineNr">3894 </span>  <span class="Comment"># screen shows second page</span>
<span id="L3895" class="LineNr">3895 </span>  screen-should-contain [
<span id="L3896" class="LineNr">3896 </span>   <span class="Constant"> .          .</span>
<span id="L3897" class="LineNr">3897 </span>   <span class="Constant"> .c         .</span>
<span id="L3898" class="LineNr">3898 </span>   <span class="Constant"> .d         .</span>
<span id="L3899" class="LineNr">3899 </span>   <span class="Constant"> .e         .</span>
<span id="L3900" class="LineNr">3900 </span>  ]
<span id="L3901" class="LineNr">3901 </span>  <span class="Comment"># scroll up again</span>
<span id="L3902" class="LineNr">3902 </span>  assume-console [
<span id="L3903" class="LineNr">3903 </span>    press <a href='003-shortcuts.mu.html#L3833'>page-up</a>
<span id="L3904" class="LineNr">3904 </span>  ]
<span id="L3905" class="LineNr">3905 </span>  run [
<span id="L3906" class="LineNr">3906 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3907" class="LineNr">3907 </span>  ]
<span id="L3908" class="LineNr">3908 </span>  <span class="Comment"># screen shows original page again</span>
<span id="L3909" class="LineNr">3909 </span>  screen-should-contain [
<span id="L3910" class="LineNr">3910 </span>   <span class="Constant"> .          .</span>
<span id="L3911" class="LineNr">3911 </span>   <span class="Constant"> .a         .</span>
<span id="L3912" class="LineNr">3912 </span>   <span class="Constant"> .b         .</span>
<span id="L3913" class="LineNr">3913 </span>   <span class="Constant"> .c         .</span>
<span id="L3914" class="LineNr">3914 </span>  ]
<span id="L3915" class="LineNr">3915 </span>]
<span id="L3916" class="LineNr">3916 </span>
<span id="L3917" class="LineNr">3917 </span><span class="muScenario">scenario</span> editor-can-scroll-up-wrapped-lines [
<span id="L3918" class="LineNr">3918 </span>  <span class="Constant">local-scope</span>
<span id="L3919" class="LineNr">3919 </span>  <span class="Comment"># screen has 1 line for menu + 5 lines for text</span>
<span id="L3920" class="LineNr">3920 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">6/height</span>
<span id="L3921" class="LineNr">3921 </span>  <span class="Comment"># editor contains a long line in the first page</span>
<span id="L3922" class="LineNr">3922 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3923" class="LineNr">3923 </span><span class="Constant">b</span>
<span id="L3924" class="LineNr">3924 </span><span class="Constant">cdefgh</span>
<span id="L3925" class="LineNr">3925 </span><span class="Constant">i</span>
<span id="L3926" class="LineNr">3926 </span><span class="Constant">j</span>
<span id="L3927" class="LineNr">3927 </span><span class="Constant">k</span>
<span id="L3928" class="LineNr">3928 </span><span class="Constant">l</span>
<span id="L3929" class="LineNr">3929 </span><span class="Constant">m</span>
<span id="L3930" class="LineNr">3930 </span><span class="Constant">n</span>
<span id="L3931" class="LineNr">3931 </span><span class="Constant">o]</span>
<span id="L3932" class="LineNr">3932 </span>  <span class="Comment"># editor screen triggers wrap of last line</span>
<span id="L3933" class="LineNr">3933 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">4/right</span>
<span id="L3934" class="LineNr">3934 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3935" class="LineNr">3935 </span>  <span class="Comment"># some part of last line is not displayed</span>
<span id="L3936" class="LineNr">3936 </span>  screen-should-contain [
<span id="L3937" class="LineNr">3937 </span>   <span class="Constant"> .          .</span>
<span id="L3938" class="LineNr">3938 </span>   <span class="Constant"> .a         .</span>
<span id="L3939" class="LineNr">3939 </span>   <span class="Constant"> .b         .</span>
<span id="L3940" class="LineNr">3940 </span>   <span class="Constant"> .cde↩      .</span>
<span id="L3941" class="LineNr">3941 </span>   <span class="Constant"> .fgh       .</span>
<span id="L3942" class="LineNr">3942 </span>   <span class="Constant"> .i         .</span>
<span id="L3943" class="LineNr">3943 </span>  ]
<span id="L3944" class="LineNr">3944 </span>  <span class="Comment"># scroll down a page and a line</span>
<span id="L3945" class="LineNr">3945 </span>  assume-console [
<span id="L3946" class="LineNr">3946 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L3947" class="LineNr">3947 </span>    left-click<span class="Constant"> 5</span>,<span class="Constant"> 0</span>
<span id="L3948" class="LineNr">3948 </span>    press down-arrow
<span id="L3949" class="LineNr">3949 </span>  ]
<span id="L3950" class="LineNr">3950 </span>  run [
<span id="L3951" class="LineNr">3951 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3952" class="LineNr">3952 </span>  ]
<span id="L3953" class="LineNr">3953 </span>  <span class="Comment"># screen shows entire wrapped line</span>
<span id="L3954" class="LineNr">3954 </span>  screen-should-contain [
<span id="L3955" class="LineNr">3955 </span>   <span class="Constant"> .          .</span>
<span id="L3956" class="LineNr">3956 </span>   <span class="Constant"> .j         .</span>
<span id="L3957" class="LineNr">3957 </span>   <span class="Constant"> .k         .</span>
<span id="L3958" class="LineNr">3958 </span>   <span class="Constant"> .l         .</span>
<span id="L3959" class="LineNr">3959 </span>   <span class="Constant"> .m         .</span>
<span id="L3960" class="LineNr">3960 </span>   <span class="Constant"> .n         .</span>
<span id="L3961" class="LineNr">3961 </span>  ]
<span id="L3962" class="LineNr">3962 </span>  <span class="Comment"># now scroll up one page</span>
<span id="L3963" class="LineNr">3963 </span>  assume-console [
<span id="L3964" class="LineNr">3964 </span>    press <a href='003-shortcuts.mu.html#L3833'>page-up</a>
<span id="L3965" class="LineNr">3965 </span>  ]
<span id="L3966" class="LineNr">3966 </span>  run [
<span id="L3967" class="LineNr">3967 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L3968" class="LineNr">3968 </span>  ]
<span id="L3969" class="LineNr">3969 </span>  <span class="Comment"># screen resets</span>
<span id="L3970" class="LineNr">3970 </span>  screen-should-contain [
<span id="L3971" class="LineNr">3971 </span>   <span class="Constant"> .          .</span>
<span id="L3972" class="LineNr">3972 </span>   <span class="Constant"> .b         .</span>
<span id="L3973" class="LineNr">3973 </span>   <span class="Constant"> .cde↩      .</span>
<span id="L3974" class="LineNr">3974 </span>   <span class="Constant"> .fgh       .</span>
<span id="L3975" class="LineNr">3975 </span>   <span class="Constant"> .i         .</span>
<span id="L3976" class="LineNr">3976 </span>   <span class="Constant"> .j         .</span>
<span id="L3977" class="LineNr">3977 </span>  ]
<span id="L3978" class="LineNr">3978 </span>]
<span id="L3979" class="LineNr">3979 </span>
<span id="L3980" class="LineNr">3980 </span><span class="muScenario">scenario</span> editor-can-scroll-up-wrapped-lines-2 [
<span id="L3981" class="LineNr">3981 </span>  <span class="Constant">local-scope</span>
<span id="L3982" class="LineNr">3982 </span>  <span class="Comment"># screen has 1 line for menu + 3 lines for text</span>
<span id="L3983" class="LineNr">3983 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L3984" class="LineNr">3984 </span>  <span class="Comment"># editor contains a very long line that occupies last two lines of screen</span>
<span id="L3985" class="LineNr">3985 </span>  <span class="Comment"># and still has something left over</span>
<span id="L3986" class="LineNr">3986 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[a</span>
<span id="L3987" class="LineNr">3987 </span><span class="Constant">bcdefgh]</span>
<span id="L3988" class="LineNr">3988 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">4/right</span>
<span id="L3989" class="LineNr">3989 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L3990" class="LineNr">3990 </span>  <span class="Comment"># some part of last line is not displayed</span>
<span id="L3991" class="LineNr">3991 </span>  screen-should-contain [
<span id="L3992" class="LineNr">3992 </span>   <span class="Constant"> .          .</span>
<span id="L3993" class="LineNr">3993 </span>   <span class="Constant"> .a         .</span>
<span id="L3994" class="LineNr">3994 </span>   <span class="Constant"> .bcd↩      .</span>
<span id="L3995" class="LineNr">3995 </span>   <span class="Constant"> .efg↩      .</span>
<span id="L3996" class="LineNr">3996 </span>  ]
<span id="L3997" class="LineNr">3997 </span>  <span class="Comment"># scroll down</span>
<span id="L3998" class="LineNr">3998 </span>  assume-console [
<span id="L3999" class="LineNr">3999 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L4000" class="LineNr">4000 </span>  ]
<span id="L4001" class="LineNr">4001 </span>  run [
<span id="L4002" class="LineNr">4002 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4003" class="LineNr">4003 </span>  ]
<span id="L4004" class="LineNr">4004 </span>  <span class="Comment"># screen shows entire wrapped line</span>
<span id="L4005" class="LineNr">4005 </span>  screen-should-contain [
<span id="L4006" class="LineNr">4006 </span>   <span class="Constant"> .          .</span>
<span id="L4007" class="LineNr">4007 </span>   <span class="Constant"> .bcd↩      .</span>
<span id="L4008" class="LineNr">4008 </span>   <span class="Constant"> .efg↩      .</span>
<span id="L4009" class="LineNr">4009 </span>   <span class="Constant"> .h         .</span>
<span id="L4010" class="LineNr">4010 </span>  ]
<span id="L4011" class="LineNr">4011 </span>  <span class="Comment"># scroll back up</span>
<span id="L4012" class="LineNr">4012 </span>  assume-console [
<span id="L4013" class="LineNr">4013 </span>    press <a href='003-shortcuts.mu.html#L3833'>page-up</a>
<span id="L4014" class="LineNr">4014 </span>  ]
<span id="L4015" class="LineNr">4015 </span>  run [
<span id="L4016" class="LineNr">4016 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4017" class="LineNr">4017 </span>  ]
<span id="L4018" class="LineNr">4018 </span>  <span class="Comment"># screen resets</span>
<span id="L4019" class="LineNr">4019 </span>  screen-should-contain [
<span id="L4020" class="LineNr">4020 </span>   <span class="Constant"> .          .</span>
<span id="L4021" class="LineNr">4021 </span>   <span class="Constant"> .a         .</span>
<span id="L4022" class="LineNr">4022 </span>   <span class="Constant"> .bcd↩      .</span>
<span id="L4023" class="LineNr">4023 </span>   <span class="Constant"> .efg↩      .</span>
<span id="L4024" class="LineNr">4024 </span>  ]
<span id="L4025" class="LineNr">4025 </span>]
<span id="L4026" class="LineNr">4026 </span>
<span id="L4027" class="LineNr">4027 </span><span class="muScenario">scenario</span> editor-can-scroll-up-past-nonempty-lines [
<span id="L4028" class="LineNr">4028 </span>  <span class="Constant">local-scope</span>
<span id="L4029" class="LineNr">4029 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L4030" class="LineNr">4030 </span>  <span class="Comment"># text with empty line in second screen</span>
<span id="L4031" class="LineNr">4031 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[axx</span>
<span id="L4032" class="LineNr">4032 </span><span class="Constant">bxx</span>
<span id="L4033" class="LineNr">4033 </span><span class="Constant">cxx</span>
<span id="L4034" class="LineNr">4034 </span><span class="Constant">dxx</span>
<span id="L4035" class="LineNr">4035 </span><span class="Constant">exx</span>
<span id="L4036" class="LineNr">4036 </span><span class="Constant">fxx</span>
<span id="L4037" class="LineNr">4037 </span><span class="Constant">gxx</span>
<span id="L4038" class="LineNr">4038 </span><span class="Constant">hxx</span>
<span id="L4039" class="LineNr">4039 </span><span class="Constant">]</span>
<span id="L4040" class="LineNr">4040 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">4/right</span>
<span id="L4041" class="LineNr">4041 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L4042" class="LineNr">4042 </span>  screen-should-contain [
<span id="L4043" class="LineNr">4043 </span>   <span class="Constant"> .          .</span>
<span id="L4044" class="LineNr">4044 </span>   <span class="Constant"> .axx       .</span>
<span id="L4045" class="LineNr">4045 </span>   <span class="Constant"> .bxx       .</span>
<span id="L4046" class="LineNr">4046 </span>   <span class="Constant"> .cxx       .</span>
<span id="L4047" class="LineNr">4047 </span>  ]
<span id="L4048" class="LineNr">4048 </span>  assume-console [
<span id="L4049" class="LineNr">4049 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L4050" class="LineNr">4050 </span>  ]
<span id="L4051" class="LineNr">4051 </span>  run [
<span id="L4052" class="LineNr">4052 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4053" class="LineNr">4053 </span>  ]
<span id="L4054" class="LineNr">4054 </span>  screen-should-contain [
<span id="L4055" class="LineNr">4055 </span>   <span class="Constant"> .          .</span>
<span id="L4056" class="LineNr">4056 </span>   <span class="Constant"> .cxx       .</span>
<span id="L4057" class="LineNr">4057 </span>   <span class="Constant"> .dxx       .</span>
<span id="L4058" class="LineNr">4058 </span>   <span class="Constant"> .exx       .</span>
<span id="L4059" class="LineNr">4059 </span>  ]
<span id="L4060" class="LineNr">4060 </span>  assume-console [
<span id="L4061" class="LineNr">4061 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L4062" class="LineNr">4062 </span>  ]
<span id="L4063" class="LineNr">4063 </span>  run [
<span id="L4064" class="LineNr">4064 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4065" class="LineNr">4065 </span>  ]
<span id="L4066" class="LineNr">4066 </span>  screen-should-contain [
<span id="L4067" class="LineNr">4067 </span>   <span class="Constant"> .          .</span>
<span id="L4068" class="LineNr">4068 </span>   <span class="Constant"> .exx       .</span>
<span id="L4069" class="LineNr">4069 </span>   <span class="Constant"> .fxx       .</span>
<span id="L4070" class="LineNr">4070 </span>   <span class="Constant"> .gxx       .</span>
<span id="L4071" class="LineNr">4071 </span>  ]
<span id="L4072" class="LineNr">4072 </span>  <span class="Comment"># scroll back up past empty line</span>
<span id="L4073" class="LineNr">4073 </span>  assume-console [
<span id="L4074" class="LineNr">4074 </span>    press <a href='003-shortcuts.mu.html#L3833'>page-up</a>
<span id="L4075" class="LineNr">4075 </span>  ]
<span id="L4076" class="LineNr">4076 </span>  run [
<span id="L4077" class="LineNr">4077 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4078" class="LineNr">4078 </span>  ]
<span id="L4079" class="LineNr">4079 </span>  screen-should-contain [
<span id="L4080" class="LineNr">4080 </span>   <span class="Constant"> .          .</span>
<span id="L4081" class="LineNr">4081 </span>   <span class="Constant"> .cxx       .</span>
<span id="L4082" class="LineNr">4082 </span>   <span class="Constant"> .dxx       .</span>
<span id="L4083" class="LineNr">4083 </span>   <span class="Constant"> .exx       .</span>
<span id="L4084" class="LineNr">4084 </span>  ]
<span id="L4085" class="LineNr">4085 </span>]
<span id="L4086" class="LineNr">4086 </span>
<span id="L4087" class="LineNr">4087 </span><span class="muScenario">scenario</span> editor-can-scroll-up-past-empty-lines [
<span id="L4088" class="LineNr">4088 </span>  <span class="Constant">local-scope</span>
<span id="L4089" class="LineNr">4089 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">4/height</span>
<span id="L4090" class="LineNr">4090 </span>  <span class="Comment"># text with empty line in second screen</span>
<span id="L4091" class="LineNr">4091 </span>  s:text <span class="Special">&lt;-</span> new <span class="Constant">[axy</span>
<span id="L4092" class="LineNr">4092 </span><span class="Constant">bxy</span>
<span id="L4093" class="LineNr">4093 </span><span class="Constant">cxy</span>
<span id="L4094" class="LineNr">4094 </span>
<span id="L4095" class="LineNr">4095 </span>dxy
<span id="L4096" class="LineNr">4096 </span>exy
<span id="L4097" class="LineNr">4097 </span>fxy
<span id="L4098" class="LineNr">4098 </span>gxy
<span id="L4099" class="LineNr">4099 </span>]
<span id="L4100" class="LineNr">4100 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> s, <span class="Constant">0/left</span>, <span class="Constant">4/right</span>
<span id="L4101" class="LineNr">4101 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L4102" class="LineNr">4102 </span>  screen-should-contain [
<span id="L4103" class="LineNr">4103 </span>   <span class="Constant"> .          .</span>
<span id="L4104" class="LineNr">4104 </span>   <span class="Constant"> .axy       .</span>
<span id="L4105" class="LineNr">4105 </span>   <span class="Constant"> .bxy       .</span>
<span id="L4106" class="LineNr">4106 </span>   <span class="Constant"> .cxy       .</span>
<span id="L4107" class="LineNr">4107 </span>  ]
<span id="L4108" class="LineNr">4108 </span>  assume-console [
<span id="L4109" class="LineNr">4109 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L4110" class="LineNr">4110 </span>  ]
<span id="L4111" class="LineNr">4111 </span>  run [
<span id="L4112" class="LineNr">4112 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4113" class="LineNr">4113 </span>  ]
<span id="L4114" class="LineNr">4114 </span>  screen-should-contain [
<span id="L4115" class="LineNr">4115 </span>   <span class="Constant"> .          .</span>
<span id="L4116" class="LineNr">4116 </span>   <span class="Constant"> .cxy       .</span>
<span id="L4117" class="LineNr">4117 </span>   <span class="Constant"> .          .</span>
<span id="L4118" class="LineNr">4118 </span>   <span class="Constant"> .dxy       .</span>
<span id="L4119" class="LineNr">4119 </span>  ]
<span id="L4120" class="LineNr">4120 </span>  assume-console [
<span id="L4121" class="LineNr">4121 </span>    press <a href='003-shortcuts.mu.html#L3610'>page-down</a>
<span id="L4122" class="LineNr">4122 </span>  ]
<span id="L4123" class="LineNr">4123 </span>  run [
<span id="L4124" class="LineNr">4124 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4125" class="LineNr">4125 </span>  ]
<span id="L4126" class="LineNr">4126 </span>  screen-should-contain [
<span id="L4127" class="LineNr">4127 </span>   <span class="Constant"> .          .</span>
<span id="L4128" class="LineNr">4128 </span>   <span class="Constant"> .dxy       .</span>
<span id="L4129" class="LineNr">4129 </span>   <span class="Constant"> .exy       .</span>
<span id="L4130" class="LineNr">4130 </span>   <span class="Constant"> .fxy       .</span>
<span id="L4131" class="LineNr">4131 </span>  ]
<span id="L4132" class="LineNr">4132 </span>  <span class="Comment"># scroll back up past empty line</span>
<span id="L4133" class="LineNr">4133 </span>  assume-console [
<span id="L4134" class="LineNr">4134 </span>    press <a href='003-shortcuts.mu.html#L3833'>page-up</a>
<span id="L4135" class="LineNr">4135 </span>  ]
<span id="L4136" class="LineNr">4136 </span>  run [
<span id="L4137" class="LineNr">4137 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4138" class="LineNr">4138 </span>  ]
<span id="L4139" class="LineNr">4139 </span>  screen-should-contain [
<span id="L4140" class="LineNr">4140 </span>   <span class="Constant"> .          .</span>
<span id="L4141" class="LineNr">4141 </span>   <span class="Constant"> .cxy       .</span>
<span id="L4142" class="LineNr">4142 </span>   <span class="Constant"> .          .</span>
<span id="L4143" class="LineNr">4143 </span>   <span class="Constant"> .dxy       .</span>
<span id="L4144" class="LineNr">4144 </span>  ]
<span id="L4145" class="LineNr">4145 </span>]
<span id="L4146" class="LineNr">4146 </span>
<span id="L4147" class="LineNr">4147 </span><span class="Comment"># ctrl-s - scroll up by one line</span>
<span id="L4148" class="LineNr">4148 </span><span class="Comment"># todo: scenarios</span>
<span id="L4149" class="LineNr">4149 </span>
<span id="L4150" class="LineNr">4150 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L4151" class="LineNr">4151 </span>  <span class="Delimiter">{</span>
<span id="L4152" class="LineNr">4152 </span>    scroll-up?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">19/ctrl-s</span>
<span id="L4153" class="LineNr">4153 </span>    <span class="muControl">break-unless</span> scroll-up?
<span id="L4154" class="LineNr">4154 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L4155" class="LineNr">4155 </span>    go-render?:bool, editor <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L4162'>line-up</a> editor, <a href='../081print.mu.html#L782'>screen-height</a>
<span id="L4156" class="LineNr">4156 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">5/line-up</span>
<span id="L4157" class="LineNr">4157 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L4158" class="LineNr">4158 </span>   <span class="muControl"> return</span> go-render?
<span id="L4159" class="LineNr">4159 </span>  <span class="Delimiter">}</span>
<span id="L4160" class="LineNr">4160 </span>]
<span id="L4161" class="LineNr">4161 </span>
<span id="L4162" class="LineNr">4162 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L4162'>line-up</a> editor:&amp;:editor, <a href='../081print.mu.html#L782'>screen-height</a>:num<span class="muRecipe"> -&gt; </span>go-render?:bool, editor:&amp;:editor [
<span id="L4163" class="LineNr">4163 </span>  <span class="Constant">local-scope</span>
<span id="L4164" class="LineNr">4164 </span>  <span class="Constant">load-inputs</span>
<span id="L4165" class="LineNr">4165 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L4166" class="LineNr">4166 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L4167" class="LineNr">4167 </span>  max:num <span class="Special">&lt;-</span> subtract right, left
<span id="L4168" class="LineNr">4168 </span>  old-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L4169" class="LineNr">4169 </span>  new-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L2862'>before-start-of-next-line</a> old-top, max
<span id="L4170" class="LineNr">4170 </span>  movement?:bool <span class="Special">&lt;-</span> not-equal old-top, new-top
<span id="L4171" class="LineNr">4171 </span>  <span class="Delimiter">{</span>
<span id="L4172" class="LineNr">4172 </span>    <span class="muControl">break-unless</span> movement?
<span id="L4173" class="LineNr">4173 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, new-top
<span id="L4174" class="LineNr">4174 </span>  <span class="Delimiter">}</span>
<span id="L4175" class="LineNr">4175 </span> <span class="muControl"> return</span> movement?
<span id="L4176" class="LineNr">4176 </span>]
<span id="L4177" class="LineNr">4177 </span>
<span id="L4178" class="LineNr">4178 </span><span class="Comment"># ctrl-x - scroll down by one line</span>
<span id="L4179" class="LineNr">4179 </span><span class="Comment"># todo: scenarios</span>
<span id="L4180" class="LineNr">4180 </span>
<span id="L4181" class="LineNr">4181 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L4182" class="LineNr">4182 </span>  <span class="Delimiter">{</span>
<span id="L4183" class="LineNr">4183 </span>    scroll-down?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">24/ctrl-x</span>
<span id="L4184" class="LineNr">4184 </span>    <span class="muControl">break-unless</span> scroll-down?
<span id="L4185" class="LineNr">4185 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L4186" class="LineNr">4186 </span>    go-render?:bool, editor <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L4193'>line-down</a> editor, <a href='../081print.mu.html#L782'>screen-height</a>
<span id="L4187" class="LineNr">4187 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">6/line-down</span>
<span id="L4188" class="LineNr">4188 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L4189" class="LineNr">4189 </span>   <span class="muControl"> return</span> go-render?
<span id="L4190" class="LineNr">4190 </span>  <span class="Delimiter">}</span>
<span id="L4191" class="LineNr">4191 </span>]
<span id="L4192" class="LineNr">4192 </span>
<span id="L4193" class="LineNr">4193 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L4193'>line-down</a> editor:&amp;:editor, <a href='../081print.mu.html#L782'>screen-height</a>:num<span class="muRecipe"> -&gt; </span>go-render?:bool, editor:&amp;:editor [
<span id="L4194" class="LineNr">4194 </span>  <span class="Constant">local-scope</span>
<span id="L4195" class="LineNr">4195 </span>  <span class="Constant">load-inputs</span>
<span id="L4196" class="LineNr">4196 </span>  old-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L4197" class="LineNr">4197 </span>  new-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1067'>before-previous-screen-line</a> old-top, editor
<span id="L4198" class="LineNr">4198 </span>  movement?:bool <span class="Special">&lt;-</span> not-equal old-top, new-top
<span id="L4199" class="LineNr">4199 </span>  <span class="Delimiter">{</span>
<span id="L4200" class="LineNr">4200 </span>    <span class="muControl">break-unless</span> movement?
<span id="L4201" class="LineNr">4201 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, new-top
<span id="L4202" class="LineNr">4202 </span>  <span class="Delimiter">}</span>
<span id="L4203" class="LineNr">4203 </span> <span class="muControl"> return</span> movement?
<span id="L4204" class="LineNr">4204 </span>]
<span id="L4205" class="LineNr">4205 </span>
<span id="L4206" class="LineNr">4206 </span><span class="Comment"># ctrl-t - move current line to top of screen</span>
<span id="L4207" class="LineNr">4207 </span><span class="Comment"># todo: scenarios</span>
<span id="L4208" class="LineNr">4208 </span>
<span id="L4209" class="LineNr">4209 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L4210" class="LineNr">4210 </span>  <span class="Delimiter">{</span>
<span id="L4211" class="LineNr">4211 </span>    scroll-down?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">20/ctrl-t</span>
<span id="L4212" class="LineNr">4212 </span>    <span class="muControl">break-unless</span> scroll-down?
<span id="L4213" class="LineNr">4213 </span><span class="Constant">    &lt;begin-move-cursor&gt;</span>
<span id="L4214" class="LineNr">4214 </span>    old-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
<span id="L4215" class="LineNr">4215 </span>    cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L4216" class="LineNr">4216 </span>    cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> cursor
<span id="L4217" class="LineNr">4217 </span>    new-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1067'>before-previous-screen-line</a> cursor, editor
<span id="L4218" class="LineNr">4218 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, new-top
<span id="L4219" class="LineNr">4219 </span>    *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>,<span class="Constant"> 1</span>
<span id="L4220" class="LineNr">4220 </span>    go-render?:bool <span class="Special">&lt;-</span> not-equal new-top, old-top
<span id="L4221" class="LineNr">4221 </span>    undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">0/never</span>
<span id="L4222" class="LineNr">4222 </span><span class="Constant">    &lt;end-move-cursor&gt;</span>
<span id="L4223" class="LineNr">4223 </span>   <span class="muControl"> return</span> go-render?
<span id="L4224" class="LineNr">4224 </span>  <span class="Delimiter">}</span>
<span id="L4225" class="LineNr">4225 </span>]
<span id="L4226" class="LineNr">4226 </span>
<span id="L4227" class="LineNr">4227 </span><span class="Comment"># ctrl-/ - comment/uncomment current line</span>
<span id="L4228" class="LineNr">4228 </span>
<span id="L4229" class="LineNr">4229 </span><span class="muRecipe">after</span> <span class="Constant"><a href='002-typing.mu.html#L185'>&lt;handle-special-character&gt;</a></span> [
<span id="L4230" class="LineNr">4230 </span>  <span class="Delimiter">{</span>
<span id="L4231" class="LineNr">4231 </span>    comment-toggle?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">31/ctrl-slash</span>
<span id="L4232" class="LineNr">4232 </span>    <span class="muControl">break-unless</span> comment-toggle?
<span id="L4233" class="LineNr">4233 </span>    cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
<span id="L4234" class="LineNr">4234 </span>    data:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
<span id="L4235" class="LineNr">4235 </span><span class="Constant">    &lt;begin-insert-character&gt;</span>
<span id="L4236" class="LineNr">4236 </span>    before-line-start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L4293'>before-start-of-screen-line</a> editor
<span id="L4237" class="LineNr">4237 </span>    line-start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-line-start
<span id="L4238" class="LineNr">4238 </span>    commented-out?:bool <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L642'>match</a> line-start, <span class="Constant">[#? ]</span>  <span class="Comment"># comment prefix</span>
<span id="L4239" class="LineNr">4239 </span>    <span class="Delimiter">{</span>
<span id="L4240" class="LineNr">4240 </span>      <span class="muControl">break-unless</span> commented-out?
<span id="L4241" class="LineNr">4241 </span>      <span class="Comment"># uncomment</span>
<span id="L4242" class="LineNr">4242 </span>      data <span class="Special">&lt;-</span> remove line-start, <span class="Constant">3/length-comment-prefix</span>, data
<span id="L4243" class="LineNr">4243 </span>      cursor-column <span class="Special">&lt;-</span> subtract cursor-column, <span class="Constant">3/length-comment-prefix</span>
<span id="L4244" class="LineNr">4244 </span>      *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L4245" class="LineNr">4245 </span>      go-render? <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L4263'>render-line-from-start</a> <a href='../081print.mu.html#L16'>screen</a>, editor, <span class="Constant">3/size-of-comment-leader</span>
<span id="L4246" class="LineNr">4246 </span>    <span class="Delimiter">}</span>
<span id="L4247" class="LineNr">4247 </span>    <span class="Delimiter">{</span>
<span id="L4248" class="LineNr">4248 </span>      <span class="muControl">break-if</span> commented-out?
<span id="L4249" class="LineNr">4249 </span>      <span class="Comment"># comment</span>
<span id="L4250" class="LineNr">4250 </span>      insert before-line-start, <span class="Constant">[#? ]</span>
<span id="L4251" class="LineNr">4251 </span>      cursor-column <span class="Special">&lt;-</span> add cursor-column, <span class="Constant">3/length-comment-prefix</span>
<span id="L4252" class="LineNr">4252 </span>      *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
<span id="L4253" class="LineNr">4253 </span>      go-render? <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L4263'>render-line-from-start</a> <a href='../081print.mu.html#L16'>screen</a>, editor,<span class="Constant"> 0</span>
<span id="L4254" class="LineNr">4254 </span>    <span class="Delimiter">}</span>
<span id="L4255" class="LineNr">4255 </span><span class="Constant">    &lt;end-insert-character&gt;</span>
<span id="L4256" class="LineNr">4256 </span>   <span class="muControl"> return</span>
<span id="L4257" class="LineNr">4257 </span>  <span class="Delimiter">}</span>
<span id="L4258" class="LineNr">4258 </span>]
<span id="L4259" class="LineNr">4259 </span>
<span id="L4260" class="LineNr">4260 </span><span class="Comment"># Render just from the start of the current line, and only if it wasn't</span>
<span id="L4261" class="LineNr">4261 </span><span class="Comment"># wrapping before (include margin) and isn't wrapping now. Otherwise just tell</span>
<span id="L4262" class="LineNr">4262 </span><span class="Comment"># the caller to go-render? the entire screen.</span>
<span id="L4263" class="LineNr">4263 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L4263'>render-line-from-start</a> <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a>, editor:&amp;:editor, right-margin:num<span class="muRecipe"> -&gt; </span>go-render?:bool, <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a> [
<span id="L4264" class="LineNr">4264 </span>  <span class="Constant">local-scope</span>
<span id="L4265" class="LineNr">4265 </span>  <span class="Constant">load-inputs</span>
<span id="L4266" class="LineNr">4266 </span>  before-line-start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L4293'>before-start-of-screen-line</a> editor
<span id="L4267" class="LineNr">4267 </span>  line-start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> before-line-start
<span id="L4268" class="LineNr">4268 </span>  color:num <span class="Special">&lt;-</span> copy <span class="Constant">7/white</span>
<span id="L4269" class="LineNr">4269 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
<span id="L4270" class="LineNr">4270 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
<span id="L4271" class="LineNr">4271 </span>  <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> move-cursor <a href='../081print.mu.html#L16'>screen</a>, cursor-row, left
<span id="L4272" class="LineNr">4272 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
<span id="L4273" class="LineNr">4273 </span>  end:num <span class="Special">&lt;-</span> subtract right, right-margin
<span id="L4274" class="LineNr">4274 </span>  i:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
<span id="L4275" class="LineNr">4275 </span>  curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy line-start
<span id="L4276" class="LineNr">4276 </span>  <span class="Delimiter">{</span>
<span id="L4277" class="LineNr">4277 </span>    render-all?:bool <span class="Special">&lt;-</span> greater-or-equal i, end
<span id="L4278" class="LineNr">4278 </span>    <span class="muControl">return-if</span> render-all?,<span class="Constant"> true/go-render</span>
<span id="L4279" class="LineNr">4279 </span>    <span class="muControl">break-unless</span> curr
<span id="L4280" class="LineNr">4280 </span>    c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
<span id="L4281" class="LineNr">4281 </span>    newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
<span id="L4282" class="LineNr">4282 </span>    <span class="muControl">break-if</span> newline?
<span id="L4283" class="LineNr">4283 </span>    color <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L400'>get-color</a> color, c
<span id="L4284" class="LineNr">4284 </span>    print <a href='../081print.mu.html#L16'>screen</a>, c, color
<span id="L4285" class="LineNr">4285 </span>    curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> curr
<span id="L4286" class="LineNr">4286 </span>    i <span class="Special">&lt;-</span> add i,<span class="Constant"> 1</span>
<span id="L4287" class="LineNr">4287 </span>   <span class="muControl"> loop</span>
<span id="L4288" class="LineNr">4288 </span>  <span class="Delimiter">}</span>
<span id="L4289" class="LineNr">4289 </span>  <a href='../081print.mu.html#L553'>clear-line-until</a> <a href='../081print.mu.html#L16'>screen</a>, right
<span id="L4290" class="LineNr">4290 </span> <span class="muControl"> return</span><span class="Constant"> false/dont-render</span>
<span id="L4291" class="LineNr">4291 </span>]
<span id="L4292" class="LineNr">4292 </span>
<span id="L4293" class="LineNr">4293 </span><span class="muRecipe">def</span> <a href='003-shortcuts.mu.html#L4293'>before-start-of-screen-line</a> editor:&amp;:editor<span class="muRecipe"> -&gt; </span>result:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char [
<span id="L4294" class="LineNr">4294 </span>  <span class="Constant">local-scope</span>
<span id="L4295" class="LineNr">4295 </span>  <span class="Constant">load-inputs</span>
<span id="L4296" class="LineNr">4296 </span>  cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
<span id="L4297" class="LineNr">4297 </span>  <span class="Delimiter">{</span>
<span id="L4298" class="LineNr">4298 </span>    <a href='../065duplex_list.mu.html#L31'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L31'>next</a> cursor
<span id="L4299" class="LineNr">4299 </span>    <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L31'>next</a>
<span id="L4300" class="LineNr">4300 </span>    cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L31'>next</a>
<span id="L4301" class="LineNr">4301 </span>  <span class="Delimiter">}</span>
<span id="L4302" class="LineNr">4302 </span>  result <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L1067'>before-previous-screen-line</a> cursor, editor
<span id="L4303" class="LineNr">4303 </span>]
<span id="L4304" class="LineNr">4304 </span>
<span id="L4305" class="LineNr">4305 </span><span class="muScenario">scenario</span> editor-comments-empty-line [
<span id="L4306" class="LineNr">4306 </span>  <span class="Constant">local-scope</span>
<span id="L4307" class="LineNr">4307 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L4308" class="LineNr">4308 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L4309" class="LineNr">4309 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L4310" class="LineNr">4310 </span>  $clear-trace
<span id="L4311" class="LineNr">4311 </span>  assume-console [
<span id="L4312" class="LineNr">4312 </span>    press ctrl-slash
<span id="L4313" class="LineNr">4313 </span>  ]
<span id="L4314" class="LineNr">4314 </span>  run [
<span id="L4315" class="LineNr">4315 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4316" class="LineNr">4316 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L4317" class="LineNr">4317 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L4318" class="LineNr">4318 </span>  ]
<span id="L4319" class="LineNr">4319 </span>  screen-should-contain [
<span id="L4320" class="LineNr">4320 </span>   <span class="Constant"> .          .</span>
<span id="L4321" class="LineNr">4321 </span>   <span class="Constant"> .#?        .</span>
<span id="L4322" class="LineNr">4322 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L4323" class="LineNr">4323 </span>   <span class="Constant"> .          .</span>
<span id="L4324" class="LineNr">4324 </span>  ]
<span id="L4325" class="LineNr">4325 </span>  memory-should-contain [
<span id="L4326" class="LineNr">4326 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L4327" class="LineNr">4327 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L4328" class="LineNr">4328 </span>  ]
<span id="L4329" class="LineNr">4329 </span>  check-trace-count-for-label<span class="Constant"> 5</span>, <span class="Constant">[print-character]</span>
<span id="L4330" class="LineNr">4330 </span>]
<span id="L4331" class="LineNr">4331 </span>
<span id="L4332" class="LineNr">4332 </span><span class="muScenario">scenario</span> editor-comments-at-start-of-contents [
<span id="L4333" class="LineNr">4333 </span>  <span class="Constant">local-scope</span>
<span id="L4334" class="LineNr">4334 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L4335" class="LineNr">4335 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[ab]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L4336" class="LineNr">4336 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L4337" class="LineNr">4337 </span>  $clear-trace
<span id="L4338" class="LineNr">4338 </span>  assume-console [
<span id="L4339" class="LineNr">4339 </span>    press ctrl-slash
<span id="L4340" class="LineNr">4340 </span>  ]
<span id="L4341" class="LineNr">4341 </span>  run [
<span id="L4342" class="LineNr">4342 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4343" class="LineNr">4343 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L4344" class="LineNr">4344 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L4345" class="LineNr">4345 </span>  ]
<span id="L4346" class="LineNr">4346 </span>  screen-should-contain [
<span id="L4347" class="LineNr">4347 </span>   <span class="Constant"> .          .</span>
<span id="L4348" class="LineNr">4348 </span>   <span class="Constant"> .#? ab     .</span>
<span id="L4349" class="LineNr">4349 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L4350" class="LineNr">4350 </span>   <span class="Constant"> .          .</span>
<span id="L4351" class="LineNr">4351 </span>  ]
<span id="L4352" class="LineNr">4352 </span>  memory-should-contain [
<span id="L4353" class="LineNr">4353 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L4354" class="LineNr">4354 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
<span id="L4355" class="LineNr">4355 </span>  ]
<span id="L4356" class="LineNr">4356 </span>  check-trace-count-for-label<span class="Constant"> 10</span>, <span class="Constant">[print-character]</span>
<span id="L4357" class="LineNr">4357 </span>]
<span id="L4358" class="LineNr">4358 </span>
<span id="L4359" class="LineNr">4359 </span><span class="muScenario">scenario</span> editor-comments-at-end-of-contents [
<span id="L4360" class="LineNr">4360 </span>  <span class="Constant">local-scope</span>
<span id="L4361" class="LineNr">4361 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L4362" class="LineNr">4362 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[ab]</span>, <span class="Constant">0/left</span>, <span class="Constant">10/right</span>
<span id="L4363" class="LineNr">4363 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L4364" class="LineNr">4364 </span>  $clear-trace
<span id="L4365" class="LineNr">4365 </span>  assume-console [
<span id="L4366" class="LineNr">4366 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 7</span>
<span id="L4367" class="LineNr">4367 </span>    press ctrl-slash
<span id="L4368" class="LineNr">4368 </span>  ]
<span id="L4369" class="LineNr">4369 </span>  run [
<span id="L4370" class="LineNr">4370 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4371" class="LineNr">4371 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L4372" class="LineNr">4372 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L4373" class="LineNr">4373 </span>  ]
<span id="L4374" class="LineNr">4374 </span>  screen-should-contain [
<span id="L4375" class="LineNr">4375 </span>   <span class="Constant"> .          .</span>
<span id="L4376" class="LineNr">4376 </span>   <span class="Constant"> .#? ab     .</span>
<span id="L4377" class="LineNr">4377 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L4378" class="LineNr">4378 </span>   <span class="Constant"> .          .</span>
<span id="L4379" class="LineNr">4379 </span>  ]
<span id="L4380" class="LineNr">4380 </span>  memory-should-contain [
<span id="L4381" class="LineNr">4381 </span>   <span class="Constant"> 4</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>
<span id="L4382" class="LineNr">4382 </span>   <span class="Constant"> 5</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>
<span id="L4383" class="LineNr">4383 </span>  ]
<span id="L4384" class="LineNr">4384 </span>  check-trace-count-for-label<span class="Constant"> 10</span>, <span class="Constant">[print-character]</span>
<span id="L4385" class="LineNr">4385 </span>  <span class="Comment"># toggle to uncomment</span>
<span id="L4386" class="LineNr">4386 </span>  $clear-trace
<span id="L4387" class="LineNr">4387 </span>  assume-console [
<span id="L4388" class="LineNr">4388 </span>    press ctrl-slash
<span id="L4389" class="LineNr">4389 </span>  ]
<span id="L4390" class="LineNr">4390 </span>  run [
<span id="L4391" class="LineNr">4391 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4392" class="LineNr">4392 </span>    4:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-row:offset</span>
<span id="L4393" class="LineNr">4393 </span>    5:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *e, <span class="Constant">cursor-column:offset</span>
<span id="L4394" class="LineNr">4394 </span>  ]
<span id="L4395" class="LineNr">4395 </span>  screen-should-contain [
<span id="L4396" class="LineNr">4396 </span>   <span class="Constant"> .          .</span>
<span id="L4397" class="LineNr">4397 </span>   <span class="Constant"> .ab        .</span>
<span id="L4398" class="LineNr">4398 </span><span class="Constant">    .╌╌╌╌╌╌╌╌╌╌.</span>
<span id="L4399" class="LineNr">4399 </span>   <span class="Constant"> .          .</span>
<span id="L4400" class="LineNr">4400 </span>  ]
<span id="L4401" class="LineNr">4401 </span>  check-trace-count-for-label<span class="Constant"> 10</span>, <span class="Constant">[print-character]</span>
<span id="L4402" class="LineNr">4402 </span>]
<span id="L4403" class="LineNr">4403 </span>
<span id="L4404" class="LineNr">4404 </span><span class="muScenario">scenario</span> editor-comments-almost-wrapping-line [
<span id="L4405" class="LineNr">4405 </span>  <span class="Constant">local-scope</span>
<span id="L4406" class="LineNr">4406 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L4407" class="LineNr">4407 </span>  <span class="Comment"># editor starts out with a non-wrapping line</span>
<span id="L4408" class="LineNr">4408 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[abcd]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L4409" class="LineNr">4409 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L4410" class="LineNr">4410 </span>  screen-should-contain [
<span id="L4411" class="LineNr">4411 </span>   <span class="Constant"> .          .</span>
<span id="L4412" class="LineNr">4412 </span>   <span class="Constant"> .abcd      .</span>
<span id="L4413" class="LineNr">4413 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L4414" class="LineNr">4414 </span>   <span class="Constant"> .          .</span>
<span id="L4415" class="LineNr">4415 </span>  ]
<span id="L4416" class="LineNr">4416 </span>  $clear-trace
<span id="L4417" class="LineNr">4417 </span>  <span class="Comment"># on commenting the line is now wrapped</span>
<span id="L4418" class="LineNr">4418 </span>  assume-console [
<span id="L4419" class="LineNr">4419 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 7</span>
<span id="L4420" class="LineNr">4420 </span>    press ctrl-slash
<span id="L4421" class="LineNr">4421 </span>  ]
<span id="L4422" class="LineNr">4422 </span>  run [
<span id="L4423" class="LineNr">4423 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4424" class="LineNr">4424 </span>  ]
<span id="L4425" class="LineNr">4425 </span>  screen-should-contain [
<span id="L4426" class="LineNr">4426 </span>   <span class="Constant"> .          .</span>
<span id="L4427" class="LineNr">4427 </span>   <span class="Constant"> .#? a↩     .</span>
<span id="L4428" class="LineNr">4428 </span>   <span class="Constant"> .bcd       .</span>
<span id="L4429" class="LineNr">4429 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L4430" class="LineNr">4430 </span>   <span class="Constant"> .          .</span>
<span id="L4431" class="LineNr">4431 </span>  ]
<span id="L4432" class="LineNr">4432 </span>]
<span id="L4433" class="LineNr">4433 </span>
<span id="L4434" class="LineNr">4434 </span><span class="muScenario">scenario</span> editor-uncomments-just-wrapping-line [
<span id="L4435" class="LineNr">4435 </span>  <span class="Constant">local-scope</span>
<span id="L4436" class="LineNr">4436 </span>  assume-screen <span class="Constant">10/width</span>, <span class="Constant">5/height</span>
<span id="L4437" class="LineNr">4437 </span>  <span class="Comment"># editor starts out with a comment that wraps the line</span>
<span id="L4438" class="LineNr">4438 </span>  e:&amp;:editor <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L51'>new-editor</a> <span class="Constant">[#? ab]</span>, <span class="Constant">0/left</span>, <span class="Constant">5/right</span>
<span id="L4439" class="LineNr">4439 </span>  <a href='002-typing.mu.html#L265'>editor-render</a> <a href='../081print.mu.html#L16'>screen</a>, e
<span id="L4440" class="LineNr">4440 </span>  screen-should-contain [
<span id="L4441" class="LineNr">4441 </span>   <span class="Constant"> .          .</span>
<span id="L4442" class="LineNr">4442 </span>   <span class="Constant"> .#? a↩     .</span>
<span id="L4443" class="LineNr">4443 </span>   <span class="Constant"> .b         .</span>
<span id="L4444" class="LineNr">4444 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L4445" class="LineNr">4445 </span>   <span class="Constant"> .          .</span>
<span id="L4446" class="LineNr">4446 </span>  ]
<span id="L4447" class="LineNr">4447 </span>  $clear-trace
<span id="L4448" class="LineNr">4448 </span>  <span class="Comment"># on uncommenting the line is no longer wrapped</span>
<span id="L4449" class="LineNr">4449 </span>  assume-console [
<span id="L4450" class="LineNr">4450 </span>    left-click<span class="Constant"> 1</span>,<span class="Constant"> 7</span>
<span id="L4451" class="LineNr">4451 </span>    press ctrl-slash
<span id="L4452" class="LineNr">4452 </span>  ]
<span id="L4453" class="LineNr">4453 </span>  run [
<span id="L4454" class="LineNr">4454 </span>    <a href='002-typing.mu.html#L16'>editor-event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, e
<span id="L4455" class="LineNr">4455 </span>  ]
<span id="L4456" class="LineNr">4456 </span>  screen-should-contain [
<span id="L4457" class="LineNr">4457 </span>   <span class="Constant"> .          .</span>
<span id="L4458" class="LineNr">4458 </span>   <span class="Constant"> .ab        .</span>
<span id="L4459" class="LineNr">4459 </span>   <span class="Constant"> .╌╌╌╌╌     .</span>
<span id="L4460" class="LineNr">4460 </span>   <span class="Constant"> .          .</span>
<span id="L4461" class="LineNr">4461 </span>  ]
<span id="L4462" class="LineNr">4462 </span>]
</pre>
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