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authorKartik K. Agaram <vc@akkartik.com>2017-06-25 14:50:16 -0700
committerKartik K. Agaram <vc@akkartik.com>2017-06-25 14:50:16 -0700
commit67160f82f285e4422927346c4ab0b5dd164b8544 (patch)
tree57b1cc8ea27e6765fdd508fc522b61610781c147
parente3c9e1536154e0dee2c15b556a2a6b9f6524e114 (diff)
downloadmu-67160f82f285e4422927346c4ab0b5dd164b8544.tar.gz
3960
Don't refresh entire sandbox side when toggling the expected result for
a single sandbox.
-rw-r--r--edit/009-sandbox-test.mu52
-rw-r--r--html/edit/009-sandbox-test.mu.html356
-rw-r--r--sandbox/009-sandbox-test.mu50
3 files changed, 265 insertions, 193 deletions
diff --git a/edit/009-sandbox-test.mu b/edit/009-sandbox-test.mu
index 5966617c..4893e1ea 100644
--- a/edit/009-sandbox-test.mu
+++ b/edit/009-sandbox-test.mu
@@ -3,7 +3,7 @@
 scenario sandbox-click-on-result-toggles-color-to-green [
   local-scope
   trace-until 100/app  # trace too long
-  assume-screen 100/width, 10/height
+  assume-screen 100/width, 20/height
   # basic recipe
   assume-resources [
     [lesson/recipes.mu] <- [
@@ -30,6 +30,7 @@ scenario sandbox-click-on-result-toggles-color-to-green [
     .                                                  ┊                                                 .
   ]
   # click on the '4' in the result
+  $clear-trace
   assume-console [
     left-click 5, 51
   ]
@@ -47,6 +48,8 @@ scenario sandbox-click-on-result-toggles-color-to-green [
     .                                                                                                    .
     .                                                                                                    .
   ]
+  # don't render entire sandbox side
+  check-trace-count-for-label-lesser-than 250, [print-character]  # say 5 sandbox lines
   # cursor should remain unmoved
   run [
     cursor:char <- copy 9251/␣
@@ -128,10 +131,19 @@ after <global-touch> [
     # identify the sandbox whose output is being clicked on
     sandbox:&:sandbox, sandbox-index:num <- find-click-in-sandbox-output env, click-row
     break-unless sandbox
-    # toggle its expected-response, and save session
+    # update it
     sandbox <- toggle-expected-response sandbox
+    # minimal update to disk
     save-sandbox resources, sandbox, sandbox-index
-    screen <- render-sandbox-side screen, env, render
+    # minimal update to screen
+    sandbox-right-margin:num <- get *current-sandbox, right:offset
+    row:num <- render-sandbox-response screen, sandbox, sandbox-left-margin, sandbox-right-margin
+    {
+      height:num <- screen-height screen
+      at-bottom?:bool <- greater-or-equal row, height
+      break-if at-bottom?
+      draw-horizontal screen, row, sandbox-left-margin, sandbox-right-margin
+    }
     screen <- update-cursor screen, recipes, current-sandbox, sandbox-in-focus?, env
     loop +next-event
   }
@@ -187,21 +199,33 @@ after <render-sandbox-response> [
   {
     break-unless sandbox-response
     *sandbox <- put *sandbox, response-starting-row-on-screen:offset, row
-    expected-response:text <- get *sandbox, expected-response:offset
-    break-unless expected-response  # fall-through to print in grey
-    response-is-expected?:bool <- equal expected-response, sandbox-response
-    {
-      break-if response-is-expected?
-      row, screen <- render-text screen, sandbox-response, left, right, 1/red, row
-    }
-    {
-      break-unless response-is-expected?:bool
-      row, screen <- render-text screen, sandbox-response, left, right, 2/green, row
-    }
+    row <- render-sandbox-response screen, sandbox, left, right
     jump +render-sandbox-end
   }
 ]
 
+def render-sandbox-response screen:&:screen, sandbox:&:sandbox, left:num, right:num -> row:num, screen:&:screen [
+  local-scope
+  load-ingredients
+  sandbox-response:text <- get *sandbox, response:offset
+  expected-response:text <- get *sandbox, expected-response:offset
+  row:num <- get *sandbox response-starting-row-on-screen:offset
+  {
+    break-if expected-response
+    row <- render-text screen, sandbox-response, left, right, 245/grey, row
+    return
+  }
+  response-is-expected?:bool <- equal expected-response, sandbox-response
+  {
+    break-if response-is-expected?
+    row <- render-text screen, sandbox-response, left, right, 1/red, row
+  }
+  {
+    break-unless response-is-expected?:bool
+    row <- render-text screen, sandbox-response, left, right, 2/green, row
+  }
+]
+
 before <end-render-sandbox-reset-hidden> [
   *sandbox <- put *sandbox, response-starting-row-on-screen:offset, 0
 ]
diff --git a/html/edit/009-sandbox-test.mu.html b/html/edit/009-sandbox-test.mu.html
index df6f864e..5b817172 100644
--- a/html/edit/009-sandbox-test.mu.html
+++ b/html/edit/009-sandbox-test.mu.html
@@ -66,7 +66,7 @@ if ('onhashchange' in window) {
 <span id="L3" class="LineNr">  3 </span><span class="muScenario">scenario</span> sandbox-click-on-result-toggles-color-to-green [
 <span id="L4" class="LineNr">  4 </span>  <span class="Constant">local-scope</span>
 <span id="L5" class="LineNr">  5 </span>  trace-until <span class="Constant">100/app</span>  <span class="Comment"># trace too long</span>
-<span id="L6" class="LineNr">  6 </span>  assume-screen <span class="Constant">100/width</span>, <span class="Constant">10/height</span>
+<span id="L6" class="LineNr">  6 </span>  assume-screen <span class="Constant">100/width</span>, <span class="Constant">20/height</span>
 <span id="L7" class="LineNr">  7 </span>  <span class="Comment"># basic recipe</span>
 <span id="L8" class="LineNr">  8 </span>  assume-resources [
 <span id="L9" class="LineNr">  9 </span>  <span class="Conceal">¦</span> <span class="Constant">[lesson/recipes.mu]</span> <span class="Special">&lt;-</span> [
@@ -93,181 +93,205 @@ if ('onhashchange' in window) {
 <span id="L30" class="LineNr"> 30 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L31" class="LineNr"> 31 </span>  ]
 <span id="L32" class="LineNr"> 32 </span>  <span class="Comment"># click on the '4' in the result</span>
-<span id="L33" class="LineNr"> 33 </span>  assume-console [
-<span id="L34" class="LineNr"> 34 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 5</span>,<span class="Constant"> 51</span>
-<span id="L35" class="LineNr"> 35 </span>  ]
-<span id="L36" class="LineNr"> 36 </span>  run [
-<span id="L37" class="LineNr"> 37 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
-<span id="L38" class="LineNr"> 38 </span>  ]
-<span id="L39" class="LineNr"> 39 </span>  <span class="Comment"># color toggles to green</span>
-<span id="L40" class="LineNr"> 40 </span>  screen-should-contain-in-color <span class="Constant">2/green</span>, [
-<span id="L41" class="LineNr"> 41 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L33" class="LineNr"> 33 </span>  $clear-trace
+<span id="L34" class="LineNr"> 34 </span>  assume-console [
+<span id="L35" class="LineNr"> 35 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 5</span>,<span class="Constant"> 51</span>
+<span id="L36" class="LineNr"> 36 </span>  ]
+<span id="L37" class="LineNr"> 37 </span>  run [
+<span id="L38" class="LineNr"> 38 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L39" class="LineNr"> 39 </span>  ]
+<span id="L40" class="LineNr"> 40 </span>  <span class="Comment"># color toggles to green</span>
+<span id="L41" class="LineNr"> 41 </span>  screen-should-contain-in-color <span class="Constant">2/green</span>, [
 <span id="L42" class="LineNr"> 42 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
 <span id="L43" class="LineNr"> 43 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
 <span id="L44" class="LineNr"> 44 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
 <span id="L45" class="LineNr"> 45 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
-<span id="L46" class="LineNr"> 46 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                   4                                                .</span>
-<span id="L47" class="LineNr"> 47 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L46" class="LineNr"> 46 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L47" class="LineNr"> 47 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                   4                                                .</span>
 <span id="L48" class="LineNr"> 48 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
-<span id="L49" class="LineNr"> 49 </span>  ]
-<span id="L50" class="LineNr"> 50 </span>  <span class="Comment"># cursor should remain unmoved</span>
-<span id="L51" class="LineNr"> 51 </span>  run [
-<span id="L52" class="LineNr"> 52 </span>  <span class="Conceal">¦</span> cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
-<span id="L53" class="LineNr"> 53 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L16'>screen</a>, cursor
-<span id="L54" class="LineNr"> 54 </span>  ]
-<span id="L55" class="LineNr"> 55 </span>  screen-should-contain [
-<span id="L56" class="LineNr"> 56 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
-<span id="L57" class="LineNr"> 57 </span>  <span class="Conceal">¦</span><span class="Constant"> .␣ecipe foo [                                      ╎                                                 .</span>
-<span id="L58" class="LineNr"> 58 </span>  <span class="Conceal">¦</span><span class="Constant"> .  reply 4                                         ╎─────────────────────────────────────────────────.</span>
-<span id="L59" class="LineNr"> 59 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎0   edit       copy       to recipe    delete    .</span>
-<span id="L60" class="LineNr"> 60 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎foo                                              .</span>
-<span id="L61" class="LineNr"> 61 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎4                                                .</span>
-<span id="L62" class="LineNr"> 62 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
-<span id="L63" class="LineNr"> 63 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
-<span id="L64" class="LineNr"> 64 </span>  ]
-<span id="L65" class="LineNr"> 65 </span>  <span class="Comment"># now change the result</span>
-<span id="L66" class="LineNr"> 66 </span>  <span class="Comment"># then rerun</span>
-<span id="L67" class="LineNr"> 67 </span>  assume-console [
-<span id="L68" class="LineNr"> 68 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 11</span>  <span class="Comment"># cursor to end of line</span>
-<span id="L69" class="LineNr"> 69 </span>  <span class="Conceal">¦</span> press backspace
-<span id="L70" class="LineNr"> 70 </span>  <span class="Conceal">¦</span> type <span class="Constant">[3]</span>
-<span id="L71" class="LineNr"> 71 </span>  <span class="Conceal">¦</span> press F4
-<span id="L72" class="LineNr"> 72 </span>  ]
-<span id="L73" class="LineNr"> 73 </span>  run [
-<span id="L74" class="LineNr"> 74 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L49" class="LineNr"> 49 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L50" class="LineNr"> 50 </span>  ]
+<span id="L51" class="LineNr"> 51 </span>  <span class="Comment"># don't render entire sandbox side</span>
+<span id="L52" class="LineNr"> 52 </span>  check-trace-count-for-label-lesser-than<span class="Constant"> 250</span>, <span class="Constant">[print-character]</span>  <span class="Comment"># say 5 sandbox lines</span>
+<span id="L53" class="LineNr"> 53 </span>  <span class="Comment"># cursor should remain unmoved</span>
+<span id="L54" class="LineNr"> 54 </span>  run [
+<span id="L55" class="LineNr"> 55 </span>  <span class="Conceal">¦</span> cursor:char <span class="Special">&lt;-</span> copy <span class="Constant">9251/␣</span>
+<span id="L56" class="LineNr"> 56 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L16'>screen</a>, cursor
+<span id="L57" class="LineNr"> 57 </span>  ]
+<span id="L58" class="LineNr"> 58 </span>  screen-should-contain [
+<span id="L59" class="LineNr"> 59 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                 run (F4)           .</span>
+<span id="L60" class="LineNr"> 60 </span>  <span class="Conceal">¦</span><span class="Constant"> .␣ecipe foo [                                      ╎                                                 .</span>
+<span id="L61" class="LineNr"> 61 </span>  <span class="Conceal">¦</span><span class="Constant"> .  reply 4                                         ╎─────────────────────────────────────────────────.</span>
+<span id="L62" class="LineNr"> 62 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎0   edit       copy       to recipe    delete    .</span>
+<span id="L63" class="LineNr"> 63 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎foo                                              .</span>
+<span id="L64" class="LineNr"> 64 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎4                                                .</span>
+<span id="L65" class="LineNr"> 65 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎─────────────────────────────────────────────────.</span>
+<span id="L66" class="LineNr"> 66 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
+<span id="L67" class="LineNr"> 67 </span>  ]
+<span id="L68" class="LineNr"> 68 </span>  <span class="Comment"># now change the result</span>
+<span id="L69" class="LineNr"> 69 </span>  <span class="Comment"># then rerun</span>
+<span id="L70" class="LineNr"> 70 </span>  assume-console [
+<span id="L71" class="LineNr"> 71 </span>  <span class="Conceal">¦</span> left-click<span class="Constant"> 2</span>,<span class="Constant"> 11</span>  <span class="Comment"># cursor to end of line</span>
+<span id="L72" class="LineNr"> 72 </span>  <span class="Conceal">¦</span> press backspace
+<span id="L73" class="LineNr"> 73 </span>  <span class="Conceal">¦</span> type <span class="Constant">[3]</span>
+<span id="L74" class="LineNr"> 74 </span>  <span class="Conceal">¦</span> press F4
 <span id="L75" class="LineNr"> 75 </span>  ]
-<span id="L76" class="LineNr"> 76 </span>  <span class="Comment"># result turns red</span>
-<span id="L77" class="LineNr"> 77 </span>  screen-should-contain-in-color <span class="Constant">1/red</span>, [
-<span id="L78" class="LineNr"> 78 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
-<span id="L79" class="LineNr"> 79 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
-<span id="L80" class="LineNr"> 80 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L76" class="LineNr"> 76 </span>  run [
+<span id="L77" class="LineNr"> 77 </span>  <span class="Conceal">¦</span> <a href='004-programming-environment.mu.html#L39'>event-loop</a> <a href='../081print.mu.html#L16'>screen</a>, <a href='../084console.mu.html#L23'>console</a>, env, <a href='../088file.mu.html#L11'>resources</a>
+<span id="L78" class="LineNr"> 78 </span>  ]
+<span id="L79" class="LineNr"> 79 </span>  <span class="Comment"># result turns red</span>
+<span id="L80" class="LineNr"> 80 </span>  screen-should-contain-in-color <span class="Constant">1/red</span>, [
 <span id="L81" class="LineNr"> 81 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
 <span id="L82" class="LineNr"> 82 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
-<span id="L83" class="LineNr"> 83 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                   3                                                .</span>
+<span id="L83" class="LineNr"> 83 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
 <span id="L84" class="LineNr"> 84 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
 <span id="L85" class="LineNr"> 85 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
-<span id="L86" class="LineNr"> 86 </span>  ]
-<span id="L87" class="LineNr"> 87 </span>]
-<span id="L88" class="LineNr"> 88 </span>
-<span id="L89" class="LineNr"> 89 </span><span class="Comment"># this requires tracking a couple more things</span>
-<span id="L90" class="LineNr"> 90 </span><span class="muData">container</span> sandbox [
-<span id="L91" class="LineNr"> 91 </span>  response-starting-row-on-screen:num
-<span id="L92" class="LineNr"> 92 </span>  expected-response:text
-<span id="L93" class="LineNr"> 93 </span>]
-<span id="L94" class="LineNr"> 94 </span>
-<span id="L95" class="LineNr"> 95 </span><span class="Comment"># include expected response when saving or restoring a sandbox</span>
-<span id="L96" class="LineNr"> 96 </span><span class="muRecipe">before</span> <span class="Constant"><a href='005-sandbox.mu.html#L251'>&lt;end-save-sandbox&gt;</a></span> [
-<span id="L97" class="LineNr"> 97 </span>  <span class="Delimiter">{</span>
-<span id="L98" class="LineNr"> 98 </span>  <span class="Conceal">¦</span> expected-response:text <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">expected-response:offset</span>
-<span id="L99" class="LineNr"> 99 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> expected-response
-<span id="L100" class="LineNr">100 </span>  <span class="Conceal">¦</span> filename <span class="Special">&lt;-</span> append filename, <span class="Constant">[.out]</span>
-<span id="L101" class="LineNr">101 </span>  <span class="Conceal">¦</span> <a href='../088file.mu.html#L11'>resources</a> <span class="Special">&lt;-</span> <a href='../088file.mu.html#L127'>dump</a> <a href='../088file.mu.html#L11'>resources</a>, filename, expected-response
-<span id="L102" class="LineNr">102 </span>  <span class="Delimiter">}</span>
-<span id="L103" class="LineNr">103 </span>]
-<span id="L104" class="LineNr">104 </span>
-<span id="L105" class="LineNr">105 </span><span class="muRecipe">before</span> <span class="Constant"><a href='005-sandbox.mu.html#L493'>&lt;end-restore-sandbox&gt;</a></span> [
-<span id="L106" class="LineNr">106 </span>  <span class="Delimiter">{</span>
-<span id="L107" class="LineNr">107 </span>  <span class="Conceal">¦</span> filename <span class="Special">&lt;-</span> append filename, <span class="Constant">[.out]</span>
-<span id="L108" class="LineNr">108 </span>  <span class="Conceal">¦</span> contents <span class="Special">&lt;-</span> <a href='../088file.mu.html#L38'>slurp</a> <a href='../088file.mu.html#L11'>resources</a>, filename
-<span id="L109" class="LineNr">109 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> contents
-<span id="L110" class="LineNr">110 </span>  <span class="Conceal">¦</span> *curr <span class="Special">&lt;-</span> put *curr, <span class="Constant">expected-response:offset</span>, contents
-<span id="L111" class="LineNr">111 </span>  <span class="Delimiter">}</span>
-<span id="L112" class="LineNr">112 </span>]
-<span id="L113" class="LineNr">113 </span>
-<span id="L114" class="LineNr">114 </span><span class="Comment"># clicks on sandbox responses save it as 'expected'</span>
-<span id="L115" class="LineNr">115 </span><span class="muRecipe">after</span> <span class="Constant"><a href='004-programming-environment.mu.html#L81'>&lt;global-touch&gt;</a></span> [
-<span id="L116" class="LineNr">116 </span>  <span class="Comment"># check if it's inside the output of any sandbox</span>
-<span id="L117" class="LineNr">117 </span>  <span class="Delimiter">{</span>
-<span id="L118" class="LineNr">118 </span>  <span class="Conceal">¦</span> sandbox-left-margin:num <span class="Special">&lt;-</span> get *current-sandbox, <span class="Constant">left:offset</span>
-<span id="L119" class="LineNr">119 </span>  <span class="Conceal">¦</span> click-column:num <span class="Special">&lt;-</span> get t, <span class="Constant">column:offset</span>
-<span id="L120" class="LineNr">120 </span>  <span class="Conceal">¦</span> on-sandbox-side?:bool <span class="Special">&lt;-</span> greater-or-equal click-column, sandbox-left-margin
-<span id="L121" class="LineNr">121 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> on-sandbox-side?
-<span id="L122" class="LineNr">122 </span>  <span class="Conceal">¦</span> first-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *env, <span class="Constant">sandbox:offset</span>
-<span id="L123" class="LineNr">123 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> first-sandbox
-<span id="L124" class="LineNr">124 </span>  <span class="Conceal">¦</span> first-sandbox-begins:num <span class="Special">&lt;-</span> get *first-sandbox, <span class="Constant">starting-row-on-screen:offset</span>
-<span id="L125" class="LineNr">125 </span>  <span class="Conceal">¦</span> click-row:num <span class="Special">&lt;-</span> get t, <span class="Constant">row:offset</span>
-<span id="L126" class="LineNr">126 </span>  <span class="Conceal">¦</span> below-sandbox-editor?:bool <span class="Special">&lt;-</span> greater-or-equal click-row, first-sandbox-begins
-<span id="L127" class="LineNr">127 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> below-sandbox-editor?
-<span id="L128" class="LineNr">128 </span>  <span class="Conceal">¦</span> <span class="Comment"># identify the sandbox whose output is being clicked on</span>
-<span id="L129" class="LineNr">129 </span>  <span class="Conceal">¦</span> sandbox:&amp;:sandbox, sandbox-index:num <span class="Special">&lt;-</span> <a href='009-sandbox-test.mu.html#L140'>find-click-in-sandbox-output</a> env, click-row
-<span id="L130" class="LineNr">130 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> sandbox
-<span id="L131" class="LineNr">131 </span>  <span class="Conceal">¦</span> <span class="Comment"># toggle its expected-response, and save session</span>
-<span id="L132" class="LineNr">132 </span>  <span class="Conceal">¦</span> sandbox <span class="Special">&lt;-</span> <a href='009-sandbox-test.mu.html#L168'>toggle-expected-response</a> sandbox
-<span id="L133" class="LineNr">133 </span>  <span class="Conceal">¦</span> <a href='005-sandbox.mu.html#L245'>save-sandbox</a> <a href='../088file.mu.html#L11'>resources</a>, sandbox, sandbox-index
-<span id="L134" class="LineNr">134 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> render-sandbox-side <a href='../081print.mu.html#L16'>screen</a>, env, <a href='001-editor.mu.html#L107'>render</a>
-<span id="L135" class="LineNr">135 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L472'>update-cursor</a> <a href='../081print.mu.html#L16'>screen</a>, recipes, current-sandbox, sandbox-in-focus?, env
-<span id="L136" class="LineNr">136 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-event</span>
-<span id="L137" class="LineNr">137 </span>  <span class="Delimiter">}</span>
-<span id="L138" class="LineNr">138 </span>]
-<span id="L139" class="LineNr">139 </span>
-<span id="L140" class="LineNr">140 </span><span class="muRecipe">def</span> <a href='009-sandbox-test.mu.html#L140'>find-click-in-sandbox-output</a> env:&amp;:environment, click-row:num<span class="muRecipe"> -&gt; </span>sandbox:&amp;:sandbox, sandbox-index:num [
-<span id="L141" class="LineNr">141 </span>  <span class="Constant">local-scope</span>
-<span id="L142" class="LineNr">142 </span>  <span class="Constant">load-ingredients</span>
-<span id="L143" class="LineNr">143 </span>  <span class="Comment"># assert click-row &gt;= sandbox.starting-row-on-screen</span>
-<span id="L144" class="LineNr">144 </span>  sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *env, <span class="Constant">sandbox:offset</span>
-<span id="L145" class="LineNr">145 </span>  start:num <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">starting-row-on-screen:offset</span>
-<span id="L146" class="LineNr">146 </span>  clicked-on-sandboxes?:bool <span class="Special">&lt;-</span> greater-or-equal click-row, start
-<span id="L147" class="LineNr">147 </span>  assert clicked-on-sandboxes?, <span class="Constant">[extract-sandbox called on click to sandbox editor]</span>
-<span id="L148" class="LineNr">148 </span>  <span class="Comment"># while click-row &lt; sandbox.next-sandbox.starting-row-on-screen</span>
-<span id="L149" class="LineNr">149 </span>  sandbox-index <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
-<span id="L150" class="LineNr">150 </span>  <span class="Delimiter">{</span>
-<span id="L151" class="LineNr">151 </span>  <span class="Conceal">¦</span> next-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">next-sandbox:offset</span>
-<span id="L152" class="LineNr">152 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> next-sandbox
-<span id="L153" class="LineNr">153 </span>  <span class="Conceal">¦</span> next-start:num <span class="Special">&lt;-</span> get *next-sandbox, <span class="Constant">starting-row-on-screen:offset</span>
-<span id="L154" class="LineNr">154 </span>  <span class="Conceal">¦</span> found?:bool <span class="Special">&lt;-</span> lesser-than click-row, next-start
-<span id="L155" class="LineNr">155 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> found?
-<span id="L156" class="LineNr">156 </span>  <span class="Conceal">¦</span> sandbox <span class="Special">&lt;-</span> copy next-sandbox
-<span id="L157" class="LineNr">157 </span>  <span class="Conceal">¦</span> sandbox-index <span class="Special">&lt;-</span> add sandbox-index,<span class="Constant"> 1</span>
-<span id="L158" class="LineNr">158 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
-<span id="L159" class="LineNr">159 </span>  <span class="Delimiter">}</span>
-<span id="L160" class="LineNr">160 </span>  <span class="Comment"># return sandbox if click is in its output region</span>
-<span id="L161" class="LineNr">161 </span>  response-starting-row:num <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">response-starting-row-on-screen:offset</span>
-<span id="L162" class="LineNr">162 </span>  <span class="muControl">return-unless</span> response-starting-row, <span class="Constant">0/no-click-in-sandbox-output</span>, <span class="Constant">0/sandbox-index</span>
-<span id="L163" class="LineNr">163 </span>  click-in-response?:bool <span class="Special">&lt;-</span> greater-or-equal click-row, response-starting-row
-<span id="L164" class="LineNr">164 </span>  <span class="muControl">return-unless</span> click-in-response?, <span class="Constant">0/no-click-in-sandbox-output</span>, <span class="Constant">0/sandbox-index</span>
-<span id="L165" class="LineNr">165 </span>  <span class="muControl">return</span> sandbox, sandbox-index
-<span id="L166" class="LineNr">166 </span>]
-<span id="L167" class="LineNr">167 </span>
-<span id="L168" class="LineNr">168 </span><span class="muRecipe">def</span> <a href='009-sandbox-test.mu.html#L168'>toggle-expected-response</a> sandbox:&amp;:sandbox<span class="muRecipe"> -&gt; </span>sandbox:&amp;:sandbox [
-<span id="L169" class="LineNr">169 </span>  <span class="Constant">local-scope</span>
-<span id="L170" class="LineNr">170 </span>  <span class="Constant">load-ingredients</span>
-<span id="L171" class="LineNr">171 </span>  expected-response:text <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">expected-response:offset</span>
-<span id="L172" class="LineNr">172 </span>  <span class="Delimiter">{</span>
-<span id="L173" class="LineNr">173 </span>  <span class="Conceal">¦</span> <span class="Comment"># if expected-response is set, reset</span>
-<span id="L174" class="LineNr">174 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> expected-response
-<span id="L175" class="LineNr">175 </span>  <span class="Conceal">¦</span> *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">expected-response:offset</span>,<span class="Constant"> 0</span>
-<span id="L176" class="LineNr">176 </span>  <span class="Delimiter">}</span>
-<span id="L177" class="LineNr">177 </span>  <span class="Delimiter">{</span>
-<span id="L178" class="LineNr">178 </span>  <span class="Conceal">¦</span> <span class="Comment"># if not, set expected response to the current response</span>
-<span id="L179" class="LineNr">179 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> expected-response
-<span id="L180" class="LineNr">180 </span>  <span class="Conceal">¦</span> response:text <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">response:offset</span>
-<span id="L181" class="LineNr">181 </span>  <span class="Conceal">¦</span> *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">expected-response:offset</span>, response
-<span id="L182" class="LineNr">182 </span>  <span class="Delimiter">}</span>
-<span id="L183" class="LineNr">183 </span>]
-<span id="L184" class="LineNr">184 </span>
-<span id="L185" class="LineNr">185 </span><span class="Comment"># when rendering a sandbox, color it in red/green if expected response exists</span>
-<span id="L186" class="LineNr">186 </span><span class="muRecipe">after</span> <span class="Constant"><a href='005-sandbox.mu.html#L314'>&lt;render-sandbox-response&gt;</a></span> [
-<span id="L187" class="LineNr">187 </span>  <span class="Delimiter">{</span>
-<span id="L188" class="LineNr">188 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> sandbox-response
-<span id="L189" class="LineNr">189 </span>  <span class="Conceal">¦</span> *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">response-starting-row-on-screen:offset</span>, row
-<span id="L190" class="LineNr">190 </span>  <span class="Conceal">¦</span> expected-response:text <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">expected-response:offset</span>
-<span id="L191" class="LineNr">191 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> expected-response  <span class="Comment"># fall-through to print in grey</span>
-<span id="L192" class="LineNr">192 </span>  <span class="Conceal">¦</span> response-is-expected?:bool <span class="Special">&lt;-</span> equal expected-response, sandbox-response
-<span id="L193" class="LineNr">193 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
-<span id="L194" class="LineNr">194 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> response-is-expected?
-<span id="L195" class="LineNr">195 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> row, <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L401'>render-text</a> <a href='../081print.mu.html#L16'>screen</a>, sandbox-response, left, right, <span class="Constant">1/red</span>, row
-<span id="L196" class="LineNr">196 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
-<span id="L197" class="LineNr">197 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
-<span id="L198" class="LineNr">198 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> response-is-expected?:bool
-<span id="L199" class="LineNr">199 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> row, <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L401'>render-text</a> <a href='../081print.mu.html#L16'>screen</a>, sandbox-response, left, right, <span class="Constant">2/green</span>, row
-<span id="L200" class="LineNr">200 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
-<span id="L201" class="LineNr">201 </span>  <span class="Conceal">¦</span> <span class="muControl">jump</span> <span class="Constant">+render-sandbox-end</span>
-<span id="L202" class="LineNr">202 </span>  <span class="Delimiter">}</span>
-<span id="L203" class="LineNr">203 </span>]
-<span id="L204" class="LineNr">204 </span>
-<span id="L205" class="LineNr">205 </span><span class="muRecipe">before</span> <span class="Constant"><a href='005-sandbox.mu.html#L328'>&lt;end-render-sandbox-reset-hidden&gt;</a></span> [
-<span id="L206" class="LineNr">206 </span>  *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">response-starting-row-on-screen:offset</span>,<span class="Constant"> 0</span>
-<span id="L207" class="LineNr">207 </span>]
+<span id="L86" class="LineNr"> 86 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                   3                                                .</span>
+<span id="L87" class="LineNr"> 87 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L88" class="LineNr"> 88 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                                                                    .</span>
+<span id="L89" class="LineNr"> 89 </span>  ]
+<span id="L90" class="LineNr"> 90 </span>]
+<span id="L91" class="LineNr"> 91 </span>
+<span id="L92" class="LineNr"> 92 </span><span class="Comment"># this requires tracking a couple more things</span>
+<span id="L93" class="LineNr"> 93 </span><span class="muData">container</span> sandbox [
+<span id="L94" class="LineNr"> 94 </span>  response-starting-row-on-screen:num
+<span id="L95" class="LineNr"> 95 </span>  expected-response:text
+<span id="L96" class="LineNr"> 96 </span>]
+<span id="L97" class="LineNr"> 97 </span>
+<span id="L98" class="LineNr"> 98 </span><span class="Comment"># include expected response when saving or restoring a sandbox</span>
+<span id="L99" class="LineNr"> 99 </span><span class="muRecipe">before</span> <span class="Constant"><a href='005-sandbox.mu.html#L251'>&lt;end-save-sandbox&gt;</a></span> [
+<span id="L100" class="LineNr">100 </span>  <span class="Delimiter">{</span>
+<span id="L101" class="LineNr">101 </span>  <span class="Conceal">¦</span> expected-response:text <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">expected-response:offset</span>
+<span id="L102" class="LineNr">102 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> expected-response
+<span id="L103" class="LineNr">103 </span>  <span class="Conceal">¦</span> filename <span class="Special">&lt;-</span> append filename, <span class="Constant">[.out]</span>
+<span id="L104" class="LineNr">104 </span>  <span class="Conceal">¦</span> <a href='../088file.mu.html#L11'>resources</a> <span class="Special">&lt;-</span> <a href='../088file.mu.html#L127'>dump</a> <a href='../088file.mu.html#L11'>resources</a>, filename, expected-response
+<span id="L105" class="LineNr">105 </span>  <span class="Delimiter">}</span>
+<span id="L106" class="LineNr">106 </span>]
+<span id="L107" class="LineNr">107 </span>
+<span id="L108" class="LineNr">108 </span><span class="muRecipe">before</span> <span class="Constant"><a href='005-sandbox.mu.html#L493'>&lt;end-restore-sandbox&gt;</a></span> [
+<span id="L109" class="LineNr">109 </span>  <span class="Delimiter">{</span>
+<span id="L110" class="LineNr">110 </span>  <span class="Conceal">¦</span> filename <span class="Special">&lt;-</span> append filename, <span class="Constant">[.out]</span>
+<span id="L111" class="LineNr">111 </span>  <span class="Conceal">¦</span> contents <span class="Special">&lt;-</span> <a href='../088file.mu.html#L38'>slurp</a> <a href='../088file.mu.html#L11'>resources</a>, filename
+<span id="L112" class="LineNr">112 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> contents
+<span id="L113" class="LineNr">113 </span>  <span class="Conceal">¦</span> *curr <span class="Special">&lt;-</span> put *curr, <span class="Constant">expected-response:offset</span>, contents
+<span id="L114" class="LineNr">114 </span>  <span class="Delimiter">}</span>
+<span id="L115" class="LineNr">115 </span>]
+<span id="L116" class="LineNr">116 </span>
+<span id="L117" class="LineNr">117 </span><span class="Comment"># clicks on sandbox responses save it as 'expected'</span>
+<span id="L118" class="LineNr">118 </span><span class="muRecipe">after</span> <span class="Constant"><a href='004-programming-environment.mu.html#L81'>&lt;global-touch&gt;</a></span> [
+<span id="L119" class="LineNr">119 </span>  <span class="Comment"># check if it's inside the output of any sandbox</span>
+<span id="L120" class="LineNr">120 </span>  <span class="Delimiter">{</span>
+<span id="L121" class="LineNr">121 </span>  <span class="Conceal">¦</span> sandbox-left-margin:num <span class="Special">&lt;-</span> get *current-sandbox, <span class="Constant">left:offset</span>
+<span id="L122" class="LineNr">122 </span>  <span class="Conceal">¦</span> click-column:num <span class="Special">&lt;-</span> get t, <span class="Constant">column:offset</span>
+<span id="L123" class="LineNr">123 </span>  <span class="Conceal">¦</span> on-sandbox-side?:bool <span class="Special">&lt;-</span> greater-or-equal click-column, sandbox-left-margin
+<span id="L124" class="LineNr">124 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> on-sandbox-side?
+<span id="L125" class="LineNr">125 </span>  <span class="Conceal">¦</span> first-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *env, <span class="Constant">sandbox:offset</span>
+<span id="L126" class="LineNr">126 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> first-sandbox
+<span id="L127" class="LineNr">127 </span>  <span class="Conceal">¦</span> first-sandbox-begins:num <span class="Special">&lt;-</span> get *first-sandbox, <span class="Constant">starting-row-on-screen:offset</span>
+<span id="L128" class="LineNr">128 </span>  <span class="Conceal">¦</span> click-row:num <span class="Special">&lt;-</span> get t, <span class="Constant">row:offset</span>
+<span id="L129" class="LineNr">129 </span>  <span class="Conceal">¦</span> below-sandbox-editor?:bool <span class="Special">&lt;-</span> greater-or-equal click-row, first-sandbox-begins
+<span id="L130" class="LineNr">130 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> below-sandbox-editor?
+<span id="L131" class="LineNr">131 </span>  <span class="Conceal">¦</span> <span class="Comment"># identify the sandbox whose output is being clicked on</span>
+<span id="L132" class="LineNr">132 </span>  <span class="Conceal">¦</span> sandbox:&amp;:sandbox, sandbox-index:num <span class="Special">&lt;-</span> <a href='009-sandbox-test.mu.html#L152'>find-click-in-sandbox-output</a> env, click-row
+<span id="L133" class="LineNr">133 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> sandbox
+<span id="L134" class="LineNr">134 </span>  <span class="Conceal">¦</span> <span class="Comment"># update it</span>
+<span id="L135" class="LineNr">135 </span>  <span class="Conceal">¦</span> sandbox <span class="Special">&lt;-</span> <a href='009-sandbox-test.mu.html#L180'>toggle-expected-response</a> sandbox
+<span id="L136" class="LineNr">136 </span>  <span class="Conceal">¦</span> <span class="Comment"># minimal update to disk</span>
+<span id="L137" class="LineNr">137 </span>  <span class="Conceal">¦</span> <a href='005-sandbox.mu.html#L245'>save-sandbox</a> <a href='../088file.mu.html#L11'>resources</a>, sandbox, sandbox-index
+<span id="L138" class="LineNr">138 </span>  <span class="Conceal">¦</span> <span class="Comment"># minimal update to screen</span>
+<span id="L139" class="LineNr">139 </span>  <span class="Conceal">¦</span> sandbox-right-margin:num <span class="Special">&lt;-</span> get *current-sandbox, <span class="Constant">right:offset</span>
+<span id="L140" class="LineNr">140 </span>  <span class="Conceal">¦</span> row:num <span class="Special">&lt;-</span> <a href='009-sandbox-test.mu.html#L207'>render-sandbox-response</a> <a href='../081print.mu.html#L16'>screen</a>, sandbox, sandbox-left-margin, sandbox-right-margin
+<span id="L141" class="LineNr">141 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L142" class="LineNr">142 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> height: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="L143" class="LineNr">143 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-bottom?:bool <span class="Special">&lt;-</span> greater-or-equal row, height
+<span id="L144" class="LineNr">144 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-bottom?
+<span id="L145" class="LineNr">145 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='002-typing.mu.html#L1116'>draw-horizontal</a> <a href='../081print.mu.html#L16'>screen</a>, row, sandbox-left-margin, sandbox-right-margin
+<span id="L146" class="LineNr">146 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L147" class="LineNr">147 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> <a href='004-programming-environment.mu.html#L472'>update-cursor</a> <a href='../081print.mu.html#L16'>screen</a>, recipes, current-sandbox, sandbox-in-focus?, env
+<span id="L148" class="LineNr">148 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-event</span>
+<span id="L149" class="LineNr">149 </span>  <span class="Delimiter">}</span>
+<span id="L150" class="LineNr">150 </span>]
+<span id="L151" class="LineNr">151 </span>
+<span id="L152" class="LineNr">152 </span><span class="muRecipe">def</span> <a href='009-sandbox-test.mu.html#L152'>find-click-in-sandbox-output</a> env:&amp;:environment, click-row:num<span class="muRecipe"> -&gt; </span>sandbox:&amp;:sandbox, sandbox-index:num [
+<span id="L153" class="LineNr">153 </span>  <span class="Constant">local-scope</span>
+<span id="L154" class="LineNr">154 </span>  <span class="Constant">load-ingredients</span>
+<span id="L155" class="LineNr">155 </span>  <span class="Comment"># assert click-row &gt;= sandbox.starting-row-on-screen</span>
+<span id="L156" class="LineNr">156 </span>  sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *env, <span class="Constant">sandbox:offset</span>
+<span id="L157" class="LineNr">157 </span>  start:num <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">starting-row-on-screen:offset</span>
+<span id="L158" class="LineNr">158 </span>  clicked-on-sandboxes?:bool <span class="Special">&lt;-</span> greater-or-equal click-row, start
+<span id="L159" class="LineNr">159 </span>  assert clicked-on-sandboxes?, <span class="Constant">[extract-sandbox called on click to sandbox editor]</span>
+<span id="L160" class="LineNr">160 </span>  <span class="Comment"># while click-row &lt; sandbox.next-sandbox.starting-row-on-screen</span>
+<span id="L161" class="LineNr">161 </span>  sandbox-index <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
+<span id="L162" class="LineNr">162 </span>  <span class="Delimiter">{</span>
+<span id="L163" class="LineNr">163 </span>  <span class="Conceal">¦</span> next-sandbox:&amp;:sandbox <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">next-sandbox:offset</span>
+<span id="L164" class="LineNr">164 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> next-sandbox
+<span id="L165" class="LineNr">165 </span>  <span class="Conceal">¦</span> next-start:num <span class="Special">&lt;-</span> get *next-sandbox, <span class="Constant">starting-row-on-screen:offset</span>
+<span id="L166" class="LineNr">166 </span>  <span class="Conceal">¦</span> found?:bool <span class="Special">&lt;-</span> lesser-than click-row, next-start
+<span id="L167" class="LineNr">167 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> found?
+<span id="L168" class="LineNr">168 </span>  <span class="Conceal">¦</span> sandbox <span class="Special">&lt;-</span> copy next-sandbox
+<span id="L169" class="LineNr">169 </span>  <span class="Conceal">¦</span> sandbox-index <span class="Special">&lt;-</span> add sandbox-index,<span class="Constant"> 1</span>
+<span id="L170" class="LineNr">170 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
+<span id="L171" class="LineNr">171 </span>  <span class="Delimiter">}</span>
+<span id="L172" class="LineNr">172 </span>  <span class="Comment"># return sandbox if click is in its output region</span>
+<span id="L173" class="LineNr">173 </span>  response-starting-row:num <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">response-starting-row-on-screen:offset</span>
+<span id="L174" class="LineNr">174 </span>  <span class="muControl">return-unless</span> response-starting-row, <span class="Constant">0/no-click-in-sandbox-output</span>, <span class="Constant">0/sandbox-index</span>
+<span id="L175" class="LineNr">175 </span>  click-in-response?:bool <span class="Special">&lt;-</span> greater-or-equal click-row, response-starting-row
+<span id="L176" class="LineNr">176 </span>  <span class="muControl">return-unless</span> click-in-response?, <span class="Constant">0/no-click-in-sandbox-output</span>, <span class="Constant">0/sandbox-index</span>
+<span id="L177" class="LineNr">177 </span>  <span class="muControl">return</span> sandbox, sandbox-index
+<span id="L178" class="LineNr">178 </span>]
+<span id="L179" class="LineNr">179 </span>
+<span id="L180" class="LineNr">180 </span><span class="muRecipe">def</span> <a href='009-sandbox-test.mu.html#L180'>toggle-expected-response</a> sandbox:&amp;:sandbox<span class="muRecipe"> -&gt; </span>sandbox:&amp;:sandbox [
+<span id="L181" class="LineNr">181 </span>  <span class="Constant">local-scope</span>
+<span id="L182" class="LineNr">182 </span>  <span class="Constant">load-ingredients</span>
+<span id="L183" class="LineNr">183 </span>  expected-response:text <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">expected-response:offset</span>
+<span id="L184" class="LineNr">184 </span>  <span class="Delimiter">{</span>
+<span id="L185" class="LineNr">185 </span>  <span class="Conceal">¦</span> <span class="Comment"># if expected-response is set, reset</span>
+<span id="L186" class="LineNr">186 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> expected-response
+<span id="L187" class="LineNr">187 </span>  <span class="Conceal">¦</span> *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">expected-response:offset</span>,<span class="Constant"> 0</span>
+<span id="L188" class="LineNr">188 </span>  <span class="Delimiter">}</span>
+<span id="L189" class="LineNr">189 </span>  <span class="Delimiter">{</span>
+<span id="L190" class="LineNr">190 </span>  <span class="Conceal">¦</span> <span class="Comment"># if not, set expected response to the current response</span>
+<span id="L191" class="LineNr">191 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> expected-response
+<span id="L192" class="LineNr">192 </span>  <span class="Conceal">¦</span> response:text <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">response:offset</span>
+<span id="L193" class="LineNr">193 </span>  <span class="Conceal">¦</span> *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">expected-response:offset</span>, response
+<span id="L194" class="LineNr">194 </span>  <span class="Delimiter">}</span>
+<span id="L195" class="LineNr">195 </span>]
+<span id="L196" class="LineNr">196 </span>
+<span id="L197" class="LineNr">197 </span><span class="Comment"># when rendering a sandbox, color it in red/green if expected response exists</span>
+<span id="L198" class="LineNr">198 </span><span class="muRecipe">after</span> <span class="Constant"><a href='005-sandbox.mu.html#L314'>&lt;render-sandbox-response&gt;</a></span> [
+<span id="L199" class="LineNr">199 </span>  <span class="Delimiter">{</span>
+<span id="L200" class="LineNr">200 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> sandbox-response
+<span id="L201" class="LineNr">201 </span>  <span class="Conceal">¦</span> *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">response-starting-row-on-screen:offset</span>, row
+<span id="L202" class="LineNr">202 </span>  <span class="Conceal">¦</span> row <span class="Special">&lt;-</span> <a href='009-sandbox-test.mu.html#L207'>render-sandbox-response</a> <a href='../081print.mu.html#L16'>screen</a>, sandbox, left, right
+<span id="L203" class="LineNr">203 </span>  <span class="Conceal">¦</span> <span class="muControl">jump</span> <span class="Constant">+render-sandbox-end</span>
+<span id="L204" class="LineNr">204 </span>  <span class="Delimiter">}</span>
+<span id="L205" class="LineNr">205 </span>]
+<span id="L206" class="LineNr">206 </span>
+<span id="L207" class="LineNr">207 </span><span class="muRecipe">def</span> <a href='009-sandbox-test.mu.html#L207'>render-sandbox-response</a> <a href='../081print.mu.html#L16'>screen</a>:&amp;:<a href='../081print.mu.html#L16'>screen</a>, sandbox:&amp;:sandbox, left:num, right: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="L208" class="LineNr">208 </span>  <span class="Constant">local-scope</span>
+<span id="L209" class="LineNr">209 </span>  <span class="Constant">load-ingredients</span>
+<span id="L210" class="LineNr">210 </span>  sandbox-response:text <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">response:offset</span>
+<span id="L211" class="LineNr">211 </span>  expected-response:text <span class="Special">&lt;-</span> get *sandbox, <span class="Constant">expected-response:offset</span>
+<span id="L212" class="LineNr">212 </span>  row:num <span class="Special">&lt;-</span> get *sandbox <span class="Constant">response-starting-row-on-screen:offset</span>
+<span id="L213" class="LineNr">213 </span>  <span class="Delimiter">{</span>
+<span id="L214" class="LineNr">214 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> expected-response
+<span id="L215" class="LineNr">215 </span>  <span class="Conceal">¦</span> row <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L401'>render-text</a> <a href='../081print.mu.html#L16'>screen</a>, sandbox-response, left, right, <span class="Constant">245/grey</span>, row
+<span id="L216" class="LineNr">216 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
+<span id="L217" class="LineNr">217 </span>  <span class="Delimiter">}</span>
+<span id="L218" class="LineNr">218 </span>  response-is-expected?:bool <span class="Special">&lt;-</span> equal expected-response, sandbox-response
+<span id="L219" class="LineNr">219 </span>  <span class="Delimiter">{</span>
+<span id="L220" class="LineNr">220 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> response-is-expected?
+<span id="L221" class="LineNr">221 </span>  <span class="Conceal">¦</span> row <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L401'>render-text</a> <a href='../081print.mu.html#L16'>screen</a>, sandbox-response, left, right, <span class="Constant">1/red</span>, row
+<span id="L222" class="LineNr">222 </span>  <span class="Delimiter">}</span>
+<span id="L223" class="LineNr">223 </span>  <span class="Delimiter">{</span>
+<span id="L224" class="LineNr">224 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> response-is-expected?:bool
+<span id="L225" class="LineNr">225 </span>  <span class="Conceal">¦</span> row <span class="Special">&lt;-</span> <a href='005-sandbox.mu.html#L401'>render-text</a> <a href='../081print.mu.html#L16'>screen</a>, sandbox-response, left, right, <span class="Constant">2/green</span>, row
+<span id="L226" class="LineNr">226 </span>  <span class="Delimiter">}</span>
+<span id="L227" class="LineNr">227 </span>]
+<span id="L228" class="LineNr">228 </span>
+<span id="L229" class="LineNr">229 </span><span class="muRecipe">before</span> <span class="Constant"><a href='005-sandbox.mu.html#L328'>&lt;end-render-sandbox-reset-hidden&gt;</a></span> [
+<span id="L230" class="LineNr">230 </span>  *sandbox <span class="Special">&lt;-</span> put *sandbox, <span class="Constant">response-starting-row-on-screen:offset</span>,<span class="Constant"> 0</span>
+<span id="L231" class="LineNr">231 </span>]
 </pre>
 </body>
 </html>
diff --git a/sandbox/009-sandbox-test.mu b/sandbox/009-sandbox-test.mu
index 65381a2b..2bd3aac9 100644
--- a/sandbox/009-sandbox-test.mu
+++ b/sandbox/009-sandbox-test.mu
@@ -30,6 +30,7 @@ scenario sandbox-click-on-result-toggles-color-to-green [
     .                                                  .
   ]
   # click on the '4' in the result
+  $clear-trace
   assume-console [
     left-click 5, 21
   ]
@@ -46,6 +47,8 @@ scenario sandbox-click-on-result-toggles-color-to-green [
     .4                                                 .
     .                                                  .
   ]
+  # don't render entire sandbox side
+  check-trace-count-for-label-lesser-than 250, [print-character]  # say 5 sandbox lines
   # cursor should remain unmoved
   run [
     cursor:char <- copy 9251/␣
@@ -130,10 +133,19 @@ after <global-touch> [
     # identify the sandbox whose output is being clicked on
     sandbox:&:sandbox, sandbox-index:num <- find-click-in-sandbox-output env, click-row
     break-unless sandbox
-    # toggle its expected-response, and save session
+    # update it
     sandbox <- toggle-expected-response sandbox
+    # minimal update to disk
     save-sandbox resources, sandbox, sandbox-index
-    screen <- render-sandbox-side screen, env, render
+    # minimal update to screen
+    sandbox-right-margin:num <- get *current-sandbox, right:offset
+    row:num <- render-sandbox-response screen, sandbox, sandbox-left-margin, sandbox-right-margin
+    {
+      height:num <- screen-height screen
+      at-bottom?:bool <- greater-or-equal row, height
+      break-if at-bottom?
+      draw-horizontal screen, row, sandbox-left-margin, sandbox-right-margin
+    }
     screen <- update-cursor screen, current-sandbox, env
     loop +next-event
   }
@@ -189,21 +201,33 @@ after <render-sandbox-response> [
   {
     break-unless sandbox-response
     *sandbox <- put *sandbox, response-starting-row-on-screen:offset, row
-    expected-response:text <- get *sandbox, expected-response:offset
-    break-unless expected-response  # fall-through to print in grey
-    response-is-expected?:bool <- equal expected-response, sandbox-response
-    {
-      break-if response-is-expected?
-      row, screen <- render-text screen, sandbox-response, left, right, 1/red, row
-    }
-    {
-      break-unless response-is-expected?:bool
-      row, screen <- render-text screen, sandbox-response, left, right, 2/green, row
-    }
+    row <- render-sandbox-response screen, sandbox, left, right
     jump +render-sandbox-end
   }
 ]
 
+def render-sandbox-response screen:&:screen, sandbox:&:sandbox, left:num, right:num -> row:num, screen:&:screen [
+  local-scope
+  load-ingredients
+  sandbox-response:text <- get *sandbox, response:offset
+  expected-response:text <- get *sandbox, expected-response:offset
+  row:num <- get *sandbox response-starting-row-on-screen:offset
+  {
+    break-if expected-response
+    row <- render-text screen, sandbox-response, left, right, 245/grey, row
+    return
+  }
+  response-is-expected?:bool <- equal expected-response, sandbox-response
+  {
+    break-if response-is-expected?
+    row <- render-text screen, sandbox-response, left, right, 1/red, row
+  }
+  {
+    break-unless response-is-expected?:bool
+    row <- render-text screen, sandbox-response, left, right, 2/green, row
+  }
+]
+
 before <end-render-sandbox-reset-hidden> [
   *sandbox <- put *sandbox, response-starting-row-on-screen:offset, 0
 ]