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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
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<title>Mu - 081print.mu</title>
<meta name="Generator" content="Vim/7.4">
<meta name="plugin-version" content="vim7.4_v2">
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* { font-size: 12pt; font-size: 1em; }
.muData { color: #ffff00; }
.muControl { color: #c0a020; }
.Delimiter { color: #800080; }
.Comment { color: #9090ff; }
.Constant { color: #00a0a0; }
.Special { color: #c00000; }
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<pre id='vimCodeElement'>
<span class="Comment"># Wrappers around print primitives that take a 'screen' object and are thus</span>
<span class="Comment"># easier to test.</span>

<span class="muData">container</span> screen [
  num-rows:num
  num-columns:num
  cursor-row:num
  cursor-column:num
  data:&amp;:@:screen-cell
]

<span class="muData">container</span> screen-cell [
  contents:char
  color:num
]

<span class="muRecipe">def</span> new-fake-screen w:num, h:num<span class="muRecipe"> -&gt; </span>result:&amp;:screen [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  result<span class="Special"> &lt;- </span>new <span class="Constant">screen:type</span>
  bufsize:num<span class="Special"> &lt;- </span>multiply w, h
  data:&amp;:@:screen-cell<span class="Special"> &lt;- </span>new <span class="Constant">screen-cell:type</span>, bufsize
  *result<span class="Special"> &lt;- </span>merge h/num-rows, w/num-columns, <span class="Constant">0/cursor-row</span>, <span class="Constant">0/cursor-column</span>, data
  result<span class="Special"> &lt;- </span>clear-screen result
]

<span class="muRecipe">def</span> clear-screen screen:&amp;:screen<span class="muRecipe"> -&gt; </span>screen:&amp;:screen [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  <span class="Comment"># if x exists</span>
  <span class="Delimiter">{</span>
    <span class="muControl">break-unless</span> screen
    <span class="Comment"># clear fake screen</span>
    buf:&amp;:@:screen-cell<span class="Special"> &lt;- </span>get *screen, <span class="Constant">data:offset</span>
    max:num<span class="Special"> &lt;- </span>length *buf
    i:num<span class="Special"> &lt;- </span>copy <span class="Constant">0</span>
    <span class="Delimiter">{</span>
      done?:bool<span class="Special"> &lt;- </span>greater-or-equal i, max
      <span class="muControl">break-if</span> done?
      curr:screen-cell<span class="Special"> &lt;- </span>merge <span class="Constant">0/empty</span>, <span class="Constant">7/white</span>
      *buf<span class="Special"> &lt;- </span>put-index *buf, i, curr
      i<span class="Special"> &lt;- </span>add i, <span class="Constant">1</span>
      <span class="muControl">loop</span>
    <span class="Delimiter">}</span>
    <span class="Comment"># reset cursor</span>
    *screen<span class="Special"> &lt;- </span>put *screen, <span class="Constant">cursor-row:offset</span>, <span class="Constant">0</span>
    *screen<span class="Special"> &lt;- </span>put *screen, <span class="Constant">cursor-column:offset</span>, <span class="Constant">0</span>
    <span class="muControl">return</span>
  <span class="Delimiter">}</span>
  <span class="Comment"># otherwise, real screen</span>
  clear-display
]

<span class="muRecipe">def</span> sync-screen screen:&amp;:screen<span class="muRecipe"> -&gt; </span>screen:&amp;:screen [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  <span class="Delimiter">{</span>
    <span class="muControl">break-if</span> screen
    sync-display
  <span class="Delimiter">}</span>
  <span class="Comment"># do nothing for fake screens</span>
]

<span class="muRecipe">def</span> fake-screen-is-empty? screen:&amp;:screen<span class="muRecipe"> -&gt; </span>result:bool [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  <span class="muControl">return-unless</span> screen, <span class="Constant">1/true</span>
  buf:&amp;:@:screen-cell<span class="Special"> &lt;- </span>get *screen, <span class="Constant">data:offset</span>
  i:num<span class="Special"> &lt;- </span>copy <span class="Constant">0</span>
  len:num<span class="Special"> &lt;- </span>length *buf
  <span class="Delimiter">{</span>
    done?:bool<span class="Special"> &lt;- </span>greater-or-equal i, len
    <span class="muControl">break-if</span> done?
    curr:screen-cell<span class="Special"> &lt;- </span>index *buf, i
    curr-contents:char<span class="Special"> &lt;- </span>get curr, <span class="Constant">contents:offset</span>
    i<span class="Special"> &lt;- </span>add i, <span class="Constant">1</span>
    <span class="muControl">loop-unless</span> curr-contents
    <span class="Comment"># not 0</span>
    <span class="muControl">return</span> <span class="Constant">0/false</span>
  <span class="Delimiter">}</span>
  <span class="muControl">return</span> <span class="Constant">1/true</span>
]

<span class="muRecipe">def</span> print screen:&amp;:screen, c:char<span class="muRecipe"> -&gt; </span>screen:&amp;:screen [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  color:num, color-found?:bool<span class="Special"> &lt;- </span><span class="Constant">next-ingredient</span>
  <span class="Delimiter">{</span>
    <span class="Comment"># default color to white</span>
    <span class="muControl">break-if</span> color-found?
    color<span class="Special"> &lt;- </span>copy <span class="Constant">7/white</span>
  <span class="Delimiter">}</span>
  bg-color:num, bg-color-found?:bool<span class="Special"> &lt;- </span><span class="Constant">next-ingredient</span>
  <span class="Delimiter">{</span>
    <span class="Comment"># default bg-color to black</span>
    <span class="muControl">break-if</span> bg-color-found?
    bg-color<span class="Special"> &lt;- </span>copy <span class="Constant">0/black</span>
  <span class="Delimiter">}</span>
  c2:num<span class="Special"> &lt;- </span>character-to-code c
  trace <span class="Constant">90</span>, <span class="Constant">[print-character]</span>, c2
  <span class="Delimiter">{</span>
    <span class="Comment"># if x exists</span>
    <span class="Comment"># (handle special cases exactly like in the real screen)</span>
    <span class="muControl">break-unless</span> screen
    width:num<span class="Special"> &lt;- </span>get *screen, <span class="Constant">num-columns:offset</span>
    height:num<span class="Special"> &lt;- </span>get *screen, <span class="Constant">num-rows:offset</span>
    <span class="Comment"># if cursor is out of bounds, silently exit</span>
    row:num<span class="Special"> &lt;- </span>get *screen, <span class="Constant">cursor-row:offset</span>
    legal?:bool<span class="Special"> &lt;- </span>greater-or-equal row, <span class="Constant">0</span>
    <span class="muControl">return-unless</span> legal?
    legal?<span class="Special"> &lt;- </span>lesser-than row, height
    <span class="muControl">return-unless</span> legal?
    column:num<span class="Special"> &lt;- </span>get *screen, <span class="Constant">cursor-column:offset</span>
    legal?<span class="Special"> &lt;- </span>greater-or-equal column, <span class="Constant">0</span>
    <span class="muControl">return-unless</span> legal?
    legal?<span class="Special"> &lt;- </span>lesser-than column, width
    <span class="muControl">return-unless</span> legal?
<span class="CommentedCode">#?     $print [print-character (], row, [, ], column, [): ], c, 10/newline</span>
    <span class="Comment"># special-case: newline</span>
    <span class="Delimiter">{</span>
      newline?:bool<span class="Special"> &lt;- </span>equal c, <span class="Constant">10/newline</span>
      <span class="muControl">break-unless</span> newline?
      <span class="Delimiter">{</span>
        <span class="Comment"># unless cursor is already at bottom</span>
        bottom:num<span class="Special"> &lt;- </span>subtract height, <span class="Constant">1</span>
        at-bottom?:bool<span class="Special"> &lt;- </span>greater-or-equal row, bottom
        <span class="muControl">break-if</span> at-bottom?
        <span class="Comment"># move it to the next row</span>
        column<span class="Special"> &lt;- </span>copy <span class="Constant">0</span>
        *screen<span class="Special"> &lt;- </span>put *screen, <span class="Constant">cursor-column:offset</span>, column
        row<span class="Special"> &lt;- </span>add row, <span class="Constant">1</span>
        *screen<span class="Special"> &lt;- </span>put *screen, <span class="Constant">cursor-row:offset</span>, row
      <span class="Delimiter">}</span>
      <span class="muControl">return</span>
    <span class="Delimiter">}</span>
    <span class="Comment"># save character in fake screen</span>
    index:num<span class="Special"> &lt;- </span>multiply row, width
    index<span class="Special"> &lt;- </span>add index, column
    buf:&amp;:@:screen-cell<span class="Special"> &lt;- </span>get *screen, <span class="Constant">data:offset</span>
    len:num<span class="Special"> &lt;- </span>length *buf
    <span class="Comment"># special-case: backspace</span>
    <span class="Delimiter">{</span>
      backspace?:bool<span class="Special"> &lt;- </span>equal c, <span class="Constant">8</span>
      <span class="muControl">break-unless</span> backspace?
      <span class="Delimiter">{</span>
        <span class="Comment"># unless cursor is already at left margin</span>
        at-left?:bool<span class="Special"> &lt;- </span>lesser-or-equal column, <span class="Constant">0</span>
        <span class="muControl">break-if</span> at-left?
        <span class="Comment"># clear previous location</span>
        column<span class="Special"> &lt;- </span>subtract column, <span class="Constant">1</span>
        *screen<span class="Special"> &lt;- </span>put *screen, <span class="Constant">cursor-column:offset</span>, column
        index<span class="Special"> &lt;- </span>subtract index, <span class="Constant">1</span>
        cursor:screen-cell<span class="Special"> &lt;- </span>merge <span class="Constant">32/space</span>, <span class="Constant">7/white</span>
        *buf<span class="Special"> &lt;- </span>put-index *buf, index, cursor
      <span class="Delimiter">}</span>
      <span class="muControl">return</span>
    <span class="Delimiter">}</span>
    cursor:screen-cell<span class="Special"> &lt;- </span>merge c, color
    *buf<span class="Special"> &lt;- </span>put-index *buf, index, cursor
    <span class="Comment"># increment column unless it's already all the way to the right</span>
    <span class="Delimiter">{</span>
      right:num<span class="Special"> &lt;- </span>subtract width, <span class="Constant">1</span>
      at-right?:bool<span class="Special"> &lt;- </span>greater-or-equal column, right
      <span class="muControl">break-if</span> at-right?
      column<span class="Special"> &lt;- </span>add column, <span class="Constant">1</span>
      *screen<span class="Special"> &lt;- </span>put *screen, <span class="Constant">cursor-column:offset</span>, column
    <span class="Delimiter">}</span>
    <span class="muControl">return</span>
  <span class="Delimiter">}</span>
  <span class="Comment"># otherwise, real screen</span>
  print-character-to-display c, color, bg-color
]

<span class="muScenario">scenario</span> print-character-at-top-left [
  <span class="Constant">local-scope</span>
  fake-screen:&amp;:screen<span class="Special"> &lt;- </span>new-fake-screen <span class="Constant">3/width</span>, <span class="Constant">2/height</span>
  run [
    a:char<span class="Special"> &lt;- </span>copy <span class="Constant">97/a</span>
    fake-screen<span class="Special"> &lt;- </span>print fake-screen, a:char
    cell:&amp;:@:screen-cell<span class="Special"> &lt;- </span>get *fake-screen, <span class="Constant">data:offset</span>
    <span class="Constant">1</span>:@:screen-cell/<span class="Special">raw &lt;- </span>copy *cell
  ]
  memory-should-contain [
    <span class="Constant">1</span><span class="Special"> &lt;- </span><span class="Constant">6</span>  <span class="Comment"># width*height</span>
    <span class="Constant">2</span><span class="Special"> &lt;- </span><span class="Constant">97</span>  <span class="Comment"># 'a'</span>
    <span class="Constant">3</span><span class="Special"> &lt;- </span><span class="Constant">7</span>  <span class="Comment"># white</span>
    <span class="Comment"># rest of screen is empty</span>
    <span class="Constant">4</span><span class="Special"> &lt;- </span><span class="Constant">0</span>
  ]
]

<span class="muScenario">scenario</span> print-character-in-color [
  <span class="Constant">local-scope</span>
  fake-screen:&amp;:screen<span class="Special"> &lt;- </span>new-fake-screen <span class="Constant">3/width</span>, <span class="Constant">2/height</span>
  run [
    a:char<span class="Special"> &lt;- </span>copy <span class="Constant">97/a</span>
    fake-screen<span class="Special"> &lt;- </span>print fake-screen, a:char, <span class="Constant">1/red</span>
    cell:&amp;:@:screen-cell<span class="Special"> &lt;- </span>get *fake-screen, <span class="Constant">data:offset</span>
    <span class="Constant">1</span>:@:screen-cell/<span class="Special">raw &lt;- </span>copy *cell
  ]
  memory-should-contain [
    <span class="Constant">1</span><span class="Special"> &lt;- </span><span class="Constant">6</span>  <span class="Comment"># width*height</span>
    <span class="Constant">2</span><span class="Special"> &lt;- </span><span class="Constant">97</span>  <span class="Comment"># 'a'</span>
    <span class="Constant">3</span><span class="Special"> &lt;- </span><span class="Constant">1</span>  <span class="Comment"># red</span>
    <span class="Comment"># rest of screen is empty</span>
    <span class="Constant">4</span><span class="Special"> &lt;- </span><span class="Constant">0</span>
  ]
]

<span class="muScenario">scenario</span> print-backspace-character [
  <span class="Constant">local-scope</span>
  fake-screen:&amp;:screen<span class="Special"> &lt;- </span>new-fake-screen <span class="Constant">3/width</span>, <span class="Constant">2/height</span>
  a:char<span class="Special"> &lt;- </span>copy <span class="Constant">97/a</span>
  fake-screen<span class="Special"> &lt;- </span>print fake-screen, a
  run [
    backspace:char<span class="Special"> &lt;- </span>copy <span class="Constant">8/backspace</span>
    fake-screen<span class="Special"> &lt;- </span>print fake-screen, backspace
    <span class="Constant">10</span>:num/<span class="Special">raw &lt;- </span>get *fake-screen, <span class="Constant">cursor-column:offset</span>
    cell:&amp;:@:screen-cell<span class="Special"> &lt;- </span>get *fake-screen, <span class="Constant">data:offset</span>
    <span class="Constant">11</span>:@:screen-cell/<span class="Special">raw &lt;- </span>copy *cell
  ]
  memory-should-contain [
    <span class="Constant">10</span><span class="Special"> &lt;- </span><span class="Constant">0</span>  <span class="Comment"># cursor column</span>
    <span class="Constant">11</span><span class="Special"> &lt;- </span><span class="Constant">6</span>  <span class="Comment"># width*height</span>
    <span class="Constant">12</span><span class="Special"> &lt;- </span><span class="Constant">32</span>  <span class="Comment"># space, not 'a'</span>
    <span class="Constant">13</span><span class="Special"> &lt;- </span><span class="Constant">7</span>  <span class="Comment"># white</span>
    <span class="Comment"># rest of screen is empty</span>
    <span class="Constant">14</span><span class="Special"> &lt;- </span><span class="Constant">0</span>
  ]
]

<span class="muScenario">scenario</span> print-extra-backspace-character [
  <span class="Constant">local-scope</span>
  fake-screen:&amp;:screen<span class="Special"> &lt;- </span>new-fake-screen <span class="Constant">3/width</span>, <span class="Constant">2/height</span>
  a:char<span class="Special"> &lt;- </span>copy <span class="Constant">97/a</span>
  fake-screen<span class="Special"> &lt;- </span>print fake-screen, a
  run [
    backspace:char<span class="Special"> &lt;- </span>copy <span class="Constant">8/backspace</span>
    fake-screen<span class="Special"> &lt;- </span>print fake-screen, backspace
    fake-screen<span class="Special"> &lt;- </span>print fake-screen, backspace  <span class="Comment"># cursor already at left margin</span>
    <span class="Constant">1</span>:num/<span class="Special">raw &lt;- </span>get *fake-screen, <span class="Constant">cursor-column:offset</span>
    cell:&amp;:@:screen-cell<span class="Special"> &lt;- </span>get *fake-screen, <span class="Constant">data:offset</span>
    <span class="Constant">3</span>:@:screen-cell/<span class="Special">raw &lt;- </span>copy *cell
  ]
  memory-should-contain [
    <span class="Constant">1</span><span class="Special"> &lt;- </span><span class="Constant">0</span>  <span class="Comment"># cursor column</span>
    <span class="Constant">3</span><span class="Special"> &lt;- </span><span class="Constant">6</span>  <span class="Comment"># width*height</span>
    <span class="Constant">4</span><span class="Special"> &lt;- </span><span class="Constant">32</span>  <span class="Comment"># space, not 'a'</span>
    <span class="Constant">5</span><span class="Special"> &lt;- </span><span class="Constant">7</span>  <span class="Comment"># white</span>
    <span class="Comment"># rest of screen is empty</span>
    <span class="Constant">6</span><span class="Special"> &lt;- </span><span class="Constant">0</span>
  ]
]

<span class="muScenario">scenario</span> print-character-at-right-margin [
  <span class="Comment"># fill top row of screen with text</span>
  <span class="Constant">local-scope</span>
  fake-screen:&amp;:screen<span class="Special"> &lt;- </span>new-fake-screen <span class="Constant">2/width</span>, <span class="Constant">2/height</span>
  a:char<span class="Special"> &lt;- </span>copy <span class="Constant">97/a</span>
  fake-screen<span class="Special"> &lt;- </span>print fake-screen, a
  b:char<span class="Special"> &lt;- </span>copy <span class="Constant">98/b</span>
  fake-screen<span class="Special"> &lt;- </span>print fake-screen, b
  run [
    <span class="Comment"># cursor now at right margin</span>
    c:char<span class="Special"> &lt;- </span>copy <span class="Constant">99/c</span>
    fake-screen<span class="Special"> &lt;- </span>print fake-screen, c
    <span class="Constant">10</span>:num/<span class="Special">raw &lt;- </span>get *fake-screen, <span class="Constant">cursor-column:offset</span>
    cell:&amp;:@:screen-cell<span class="Special"> &lt;- </span>get *fake-screen, <span class="Constant">data:offset</span>
    <span class="Constant">11</span>:@:screen-cell/<span class="Special">raw &lt;- </span>copy *cell
  ]
  memory-should-contain [
    <span class="Constant">10</span><span class="Special"> &lt;- </span><span class="Constant">1</span>  <span class="Comment"># cursor column</span>
    <span class="Constant">11</span><span class="Special"> &lt;- </span><span class="Constant">4</span>  <span class="Comment"># width*height</span>
    <span class="Constant">12</span><span class="Special"> &lt;- </span><span class="Constant">97</span>  <span class="Comment"># 'a'</span>
    <span class="Constant">13</span><span class="Special"> &lt;- </span><span class="Constant">7</span>  <span class="Comment"># white</span>
    <span class="Constant">14</span><span class="Special"> &lt;- </span><span class="Constant">99</span>  <span class="Comment"># 'c' over 'b'</span>
    <span class="Constant">15</span><span class="Special"> &lt;- </span><span class="Constant">7</span>  <span class="Comment"># white</span>
    <span class="Comment"># rest of screen is empty</span>
    <span class="Constant">16</span><span class="Special"> &lt;- </span><span class="Constant">0</span>
  ]
]

<span class="muScenario">scenario</span> print-newline-character [
  <span class="Constant">local-scope</span>
  fake-screen:&amp;:screen<span class="Special"> &lt;- </span>new-fake-screen <span class="Constant">3/width</span>, <span class="Constant">2/height</span>
  a:char<span class="Special"> &lt;- </span>copy <span class="Constant">97/a</span>
  fake-screen<span class="Special"> &lt;- </span>print fake-screen, a
  run [
    newline:char<span class="Special"> &lt;- </span>copy <span class="Constant">10/newline</span>
    fake-screen<span class="Special"> &lt;- </span>print fake-screen, newline
    <span class="Constant">10</span>:num/<span class="Special">raw &lt;- </span>get *fake-screen, <span class="Constant">cursor-row:offset</span>
    <span class="Constant">11</span>:num/<span class="Special">raw &lt;- </span>get *fake-screen, <span class="Constant">cursor-column:offset</span>
    cell:&amp;:@:screen-cell<span class="Special"> &lt;- </span>get *fake-screen, <span class="Constant">data:offset</span>
    <span class="Constant">12</span>:@:screen-cell/<span class="Special">raw &lt;- </span>copy *cell
  ]
  memory-should-contain [
    <span class="Constant">10</span><span class="Special"> &lt;- </span><span class="Constant">1</span>  <span class="Comment"># cursor row</span>
    <span class="Constant">11</span><span class="Special"> &lt;- </span><span class="Constant">0</span>  <span class="Comment"># cursor column</span>
    <span class="Constant">12</span><span class="Special"> &lt;- </span><span class="Constant">6</span>  <span class="Comment"># width*height</span>
    <span class="Constant">13</span><span class="Special"> &lt;- </span><span class="Constant">97</span>  <span class="Comment"># 'a'</span>
    <span class="Constant">14</span><span class="Special"> &lt;- </span><span class="Constant">7</span>  <span class="Comment"># white</span>
    <span class="Comment"># rest of screen is empty</span>
    <span class="Constant">15</span><span class="Special"> &lt;- </span><span class="Constant">0</span>
  ]
]

<span class="muScenario">scenario</span> print-newline-at-bottom-line [
  <span class="Constant">local-scope</span>
  fake-screen:&amp;:screen<span class="Special"> &lt;- </span>new-fake-screen <span class="Constant">3/width</span>, <span class="Constant">2/height</span>
  newline:char<span class="Special"> &lt;- </span>copy <span class="Constant">10/newline</span>
  fake-screen<span class="Special"> &lt;- </span>print fake-screen, newline
  fake-screen<span class="Special"> &lt;- </span>print fake-screen, newline
  run [
    <span class="Comment"># cursor now at bottom of screen</span>
    fake-screen<span class="Special"> &lt;- </span>print fake-screen, newline
    <span class="Constant">10</span>:num/<span class="Special">raw &lt;- </span>get *fake-screen, <span class="Constant">cursor-row:offset</span>
    <span class="Constant">11</span>:num/<span class="Special">raw &lt;- </span>get *fake-screen, <span class="Constant">cursor-column:offset</span>
  ]
  <span class="Comment"># doesn't move further down</span>
  memory-should-contain [
    <span class="Constant">10</span><span class="Special"> &lt;- </span><span class="Constant">1</span>  <span class="Comment"># cursor row</span>
    <span class="Constant">11</span><span class="Special"> &lt;- </span><span class="Constant">0</span>  <span class="Comment"># cursor column</span>
  ]
]

<span class="muScenario">scenario</span> print-character-at-bottom-right [
  <span class="Constant">local-scope</span>
  fake-screen:&amp;:screen<span class="Special"> &lt;- </span>new-fake-screen <span class="Constant">2/width</span>, <span class="Constant">2/height</span>
  newline:char<span class="Special"> &lt;- </span>copy <span class="Constant">10/newline</span>
  fake-screen<span class="Special"> &lt;- </span>print fake-screen, newline
  a:char<span class="Special"> &lt;- </span>copy <span class="Constant">97/a</span>
  fake-screen<span class="Special"> &lt;- </span>print fake-screen, a
  b:char<span class="Special"> &lt;- </span>copy <span class="Constant">98/b</span>
  fake-screen<span class="Special"> &lt;- </span>print fake-screen, b
  c:char<span class="Special"> &lt;- </span>copy <span class="Constant">99/c</span>
  fake-screen<span class="Special"> &lt;- </span>print fake-screen, c
  fake-screen<span class="Special"> &lt;- </span>print fake-screen, newline
  run [
    <span class="Comment"># cursor now at bottom right</span>
    d:char<span class="Special"> &lt;- </span>copy <span class="Constant">100/d</span>
    fake-screen<span class="Special"> &lt;- </span>print fake-screen, d
    <span class="Constant">10</span>:num/<span class="Special">raw &lt;- </span>get *fake-screen, <span class="Constant">cursor-row:offset</span>
    <span class="Constant">11</span>:num/<span class="Special">raw &lt;- </span>get *fake-screen, <span class="Constant">cursor-column:offset</span>
    cell:&amp;:@:screen-cell<span class="Special"> &lt;- </span>get *fake-screen, <span class="Constant">data:offset</span>
    <span class="Constant">20</span>:@:screen-cell/<span class="Special">raw &lt;- </span>copy *cell
  ]
  memory-should-contain [
    <span class="Constant">10</span><span class="Special"> &lt;- </span><span class="Constant">1</span>  <span class="Comment"># cursor row</span>
    <span class="Constant">11</span><span class="Special"> &lt;- </span><span class="Constant">1</span>  <span class="Comment"># cursor column</span>
    <span class="Constant">20</span><span class="Special"> &lt;- </span><span class="Constant">4</span>  <span class="Comment"># width*height</span>
    <span class="Constant">21</span><span class="Special"> &lt;- </span><span class="Constant">0</span>  <span class="Comment"># unused</span>
    <span class="Constant">22</span><span class="Special"> &lt;- </span><span class="Constant">7</span>  <span class="Comment"># white</span>
    <span class="Constant">23</span><span class="Special"> &lt;- </span><span class="Constant">0</span>  <span class="Comment"># unused</span>
    <span class="Constant">24</span><span class="Special"> &lt;- </span><span class="Constant">7</span>  <span class="Comment"># white</span>
    <span class="Constant">25</span><span class="Special"> &lt;- </span><span class="Constant">97</span> <span class="Comment"># 'a'</span>
    <span class="Constant">26</span><span class="Special"> &lt;- </span><span class="Constant">7</span>  <span class="Comment"># white</span>
    <span class="Constant">27</span><span class="Special"> &lt;- </span><span class="Constant">100</span>  <span class="Comment"># 'd' over 'b' and 'c' and newline</span>
    <span class="Constant">28</span><span class="Special"> &lt;- </span><span class="Constant">7</span>  <span class="Comment"># white</span>
    <span class="Comment"># rest of screen is empty</span>
    <span class="Constant">29</span><span class="Special"> &lt;- </span><span class="Constant">0</span>
  ]
]

<span class="muRecipe">def</span> clear-line screen:&amp;:screen<span class="muRecipe"> -&gt; </span>screen:&amp;:screen [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  space:char<span class="Special"> &lt;- </span>copy <span class="Constant">0/nul</span>
  <span class="Comment"># if x exists, clear line in fake screen</span>
  <span class="Delimiter">{</span>
    <span class="muControl">break-unless</span> screen
    width:num<span class="Special"> &lt;- </span>get *screen, <span class="Constant">num-columns:offset</span>
    column:num<span class="Special"> &lt;- </span>get *screen, <span class="Constant">cursor-column:offset</span>
    original-column:num<span class="Special"> &lt;- </span>copy column
    <span class="Comment"># space over the entire line</span>
    <span class="Delimiter">{</span>
      right:num<span class="Special"> &lt;- </span>subtract width, <span class="Constant">1</span>
      done?:bool<span class="Special"> &lt;- </span>greater-or-equal column, right
      <span class="muControl">break-if</span> done?
      print screen, space
      column<span class="Special"> &lt;- </span>add column, <span class="Constant">1</span>
      <span class="muControl">loop</span>
    <span class="Delimiter">}</span>
    <span class="Comment"># now back to where the cursor was</span>
    *screen<span class="Special"> &lt;- </span>put *screen, <span class="Constant">cursor-column:offset</span>, original-column
    <span class="muControl">return</span>
  <span class="Delimiter">}</span>
  <span class="Comment"># otherwise, real screen</span>
  clear-line-on-display
]

<span class="muRecipe">def</span> clear-line-until screen:&amp;:screen, right:num/inclusive<span class="muRecipe"> -&gt; </span>screen:&amp;:screen [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  _, column:num<span class="Special"> &lt;- </span>cursor-position screen
  space:char<span class="Special"> &lt;- </span>copy <span class="Constant">32/space</span>
  bg-color:num, bg-color-found?:bool<span class="Special"> &lt;- </span><span class="Constant">next-ingredient</span>
  <span class="Delimiter">{</span>
    <span class="Comment"># default bg-color to black</span>
    <span class="muControl">break-if</span> bg-color-found?
    bg-color<span class="Special"> &lt;- </span>copy <span class="Constant">0/black</span>
  <span class="Delimiter">}</span>
  <span class="Delimiter">{</span>
    done?:bool<span class="Special"> &lt;- </span>greater-than column, right
    <span class="muControl">break-if</span> done?
    screen<span class="Special"> &lt;- </span>print screen, space, <span class="Constant">7/white</span>, bg-color  <span class="Comment"># foreground color is mostly unused except if the cursor shows up at this cell</span>
    column<span class="Special"> &lt;- </span>add column, <span class="Constant">1</span>
    <span class="muControl">loop</span>
  <span class="Delimiter">}</span>
]

<span class="muRecipe">def</span> cursor-position screen:&amp;:screen<span class="muRecipe"> -&gt; </span>row:num, column:num [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  <span class="Comment"># if x exists, lookup cursor in fake screen</span>
  <span class="Delimiter">{</span>
    <span class="muControl">break-unless</span> screen
    row:num<span class="Special"> &lt;- </span>get *screen, <span class="Constant">cursor-row:offset</span>
    column:num<span class="Special"> &lt;- </span>get *screen, <span class="Constant">cursor-column:offset</span>
    <span class="muControl">return</span>
  <span class="Delimiter">}</span>
  row, column<span class="Special"> &lt;- </span>cursor-position-on-display
]

<span class="muRecipe">def</span> move-cursor screen:&amp;:screen, new-row:num, new-column:num<span class="muRecipe"> -&gt; </span>screen:&amp;:screen [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  <span class="Comment"># if x exists, move cursor in fake screen</span>
  <span class="Delimiter">{</span>
    <span class="muControl">break-unless</span> screen
    *screen<span class="Special"> &lt;- </span>put *screen, <span class="Constant">cursor-row:offset</span>, new-row
    *screen<span class="Special"> &lt;- </span>put *screen, <span class="Constant">cursor-column:offset</span>, new-column
    <span class="muControl">return</span>
  <span class="Delimiter">}</span>
  <span class="Comment"># otherwise, real screen</span>
  move-cursor-on-display new-row, new-column
]

<span class="muScenario">scenario</span> clear-line-erases-printed-characters [
  <span class="Constant">local-scope</span>
  fake-screen:&amp;:screen<span class="Special"> &lt;- </span>new-fake-screen <span class="Constant">3/width</span>, <span class="Constant">2/height</span>
  <span class="Comment"># print a character</span>
  a:char<span class="Special"> &lt;- </span>copy <span class="Constant">97/a</span>
  fake-screen<span class="Special"> &lt;- </span>print fake-screen, a
  <span class="Comment"># move cursor to start of line</span>
  fake-screen<span class="Special"> &lt;- </span>move-cursor fake-screen, <span class="Constant">0/row</span>, <span class="Constant">0/column</span>
  run [
    fake-screen<span class="Special"> &lt;- </span>clear-line fake-screen
    cell:&amp;:@:screen-cell<span class="Special"> &lt;- </span>get *fake-screen, <span class="Constant">data:offset</span>
    <span class="Constant">10</span>:@:screen-cell/<span class="Special">raw &lt;- </span>copy *cell
  ]
  <span class="Comment"># screen should be blank</span>
  memory-should-contain [
    <span class="Constant">10</span><span class="Special"> &lt;- </span><span class="Constant">6</span>  <span class="Comment"># width*height</span>
    <span class="Constant">11</span><span class="Special"> &lt;- </span><span class="Constant">0</span>
    <span class="Constant">12</span><span class="Special"> &lt;- </span><span class="Constant">7</span>
    <span class="Constant">13</span><span class="Special"> &lt;- </span><span class="Constant">0</span>
    <span class="Constant">14</span><span class="Special"> &lt;- </span><span class="Constant">7</span>
    <span class="Constant">15</span><span class="Special"> &lt;- </span><span class="Constant">0</span>
    <span class="Constant">16</span><span class="Special"> &lt;- </span><span class="Constant">7</span>
    <span class="Constant">17</span><span class="Special"> &lt;- </span><span class="Constant">0</span>
    <span class="Constant">18</span><span class="Special"> &lt;- </span><span class="Constant">7</span>
    <span class="Constant">19</span><span class="Special"> &lt;- </span><span class="Constant">0</span>
    <span class="Constant">20</span><span class="Special"> &lt;- </span><span class="Constant">7</span>
    <span class="Constant">21</span><span class="Special"> &lt;- </span><span class="Constant">0</span>
    <span class="Constant">22</span><span class="Special"> &lt;- </span><span class="Constant">7</span>
  ]
]

<span class="muRecipe">def</span> cursor-down screen:&amp;:screen<span class="muRecipe"> -&gt; </span>screen:&amp;:screen [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  <span class="Comment"># if x exists, move cursor in fake screen</span>
  <span class="Delimiter">{</span>
    <span class="muControl">break-unless</span> screen
    <span class="Delimiter">{</span>
      <span class="Comment"># increment row unless it's already all the way down</span>
      height:num<span class="Special"> &lt;- </span>get *screen, <span class="Constant">num-rows:offset</span>
      row:num<span class="Special"> &lt;- </span>get *screen, <span class="Constant">cursor-row:offset</span>
      max:num<span class="Special"> &lt;- </span>subtract height, <span class="Constant">1</span>
      at-bottom?:bool<span class="Special"> &lt;- </span>greater-or-equal row, max
      <span class="muControl">break-if</span> at-bottom?
      row<span class="Special"> &lt;- </span>add row, <span class="Constant">1</span>
      *screen<span class="Special"> &lt;- </span>put *screen, <span class="Constant">cursor-row:offset</span>, row
    <span class="Delimiter">}</span>
    <span class="muControl">return</span>
  <span class="Delimiter">}</span>
  <span class="Comment"># otherwise, real screen</span>
  move-cursor-down-on-display
]

<span class="muRecipe">def</span> cursor-up screen:&amp;:screen<span class="muRecipe"> -&gt; </span>screen:&amp;:screen [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  <span class="Comment"># if x exists, move cursor in fake screen</span>
  <span class="Delimiter">{</span>
    <span class="muControl">break-unless</span> screen
    <span class="Delimiter">{</span>
      <span class="Comment"># decrement row unless it's already all the way up</span>
      row:num<span class="Special"> &lt;- </span>get *screen, <span class="Constant">cursor-row:offset</span>
      at-top?:bool<span class="Special"> &lt;- </span>lesser-or-equal row, <span class="Constant">0</span>
      <span class="muControl">break-if</span> at-top?
      row<span class="Special"> &lt;- </span>subtract row, <span class="Constant">1</span>
      *screen<span class="Special"> &lt;- </span>put *screen, <span class="Constant">cursor-row:offset</span>, row
    <span class="Delimiter">}</span>
    <span class="muControl">return</span>
  <span class="Delimiter">}</span>
  <span class="Comment"># otherwise, real screen</span>
  move-cursor-up-on-display
]

<span class="muRecipe">def</span> cursor-right screen:&amp;:screen<span class="muRecipe"> -&gt; </span>screen:&amp;:screen [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  <span class="Comment"># if x exists, move cursor in fake screen</span>
  <span class="Delimiter">{</span>
    <span class="muControl">break-unless</span> screen
    <span class="Delimiter">{</span>
      <span class="Comment"># increment column unless it's already all the way to the right</span>
      width:num<span class="Special"> &lt;- </span>get *screen, <span class="Constant">num-columns:offset</span>
      column:num<span class="Special"> &lt;- </span>get *screen, <span class="Constant">cursor-column:offset</span>
      max:num<span class="Special"> &lt;- </span>subtract width, <span class="Constant">1</span>
      at-bottom?:bool<span class="Special"> &lt;- </span>greater-or-equal column, max
      <span class="muControl">break-if</span> at-bottom?
      column<span class="Special"> &lt;- </span>add column, <span class="Constant">1</span>
      *screen<span class="Special"> &lt;- </span>put *screen, <span class="Constant">cursor-column:offset</span>, column
    <span class="Delimiter">}</span>
    <span class="muControl">return</span>
  <span class="Delimiter">}</span>
  <span class="Comment"># otherwise, real screen</span>
  move-cursor-right-on-display
]

<span class="muRecipe">def</span> cursor-left screen:&amp;:screen<span class="muRecipe"> -&gt; </span>screen:&amp;:screen [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  <span class="Comment"># if x exists, move cursor in fake screen</span>
  <span class="Delimiter">{</span>
    <span class="muControl">break-unless</span> screen
    <span class="Delimiter">{</span>
      <span class="Comment"># decrement column unless it's already all the way to the left</span>
      column:num<span class="Special"> &lt;- </span>get *screen, <span class="Constant">cursor-column:offset</span>
      at-top?:bool<span class="Special"> &lt;- </span>lesser-or-equal column, <span class="Constant">0</span>
      <span class="muControl">break-if</span> at-top?
      column<span class="Special"> &lt;- </span>subtract column, <span class="Constant">1</span>
      *screen<span class="Special"> &lt;- </span>put *screen, <span class="Constant">cursor-column:offset</span>, column
    <span class="Delimiter">}</span>
    <span class="muControl">return</span>
  <span class="Delimiter">}</span>
  <span class="Comment"># otherwise, real screen</span>
  move-cursor-left-on-display
]

<span class="muRecipe">def</span> cursor-to-start-of-line screen:&amp;:screen<span class="muRecipe"> -&gt; </span>screen:&amp;:screen [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  row:num<span class="Special"> &lt;- </span>cursor-position screen
  column:num<span class="Special"> &lt;- </span>copy <span class="Constant">0</span>
  screen<span class="Special"> &lt;- </span>move-cursor screen, row, column
]

<span class="muRecipe">def</span> cursor-to-next-line screen:&amp;:screen<span class="muRecipe"> -&gt; </span>screen:&amp;:screen [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  screen<span class="Special"> &lt;- </span>cursor-down screen
  screen<span class="Special"> &lt;- </span>cursor-to-start-of-line screen
]

<span class="muRecipe">def</span> move-cursor-to-column screen:&amp;:screen, column:num<span class="muRecipe"> -&gt; </span>screen:&amp;:screen [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  row:num, _<span class="Special"> &lt;- </span>cursor-position screen
  move-cursor screen, row, column
]

<span class="muRecipe">def</span> screen-width screen:&amp;:screen<span class="muRecipe"> -&gt; </span>width:num [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  <span class="Comment"># if x exists, move cursor in fake screen</span>
  <span class="Delimiter">{</span>
    <span class="muControl">break-unless</span> screen
    width<span class="Special"> &lt;- </span>get *screen, <span class="Constant">num-columns:offset</span>
    <span class="muControl">return</span>
  <span class="Delimiter">}</span>
  <span class="Comment"># otherwise, real screen</span>
  width<span class="Special"> &lt;- </span>display-width
]

<span class="muRecipe">def</span> screen-height screen:&amp;:screen<span class="muRecipe"> -&gt; </span>height:num [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  <span class="Comment"># if x exists, move cursor in fake screen</span>
  <span class="Delimiter">{</span>
    <span class="muControl">break-unless</span> screen
    height<span class="Special"> &lt;- </span>get *screen, <span class="Constant">num-rows:offset</span>
    <span class="muControl">return</span>
  <span class="Delimiter">}</span>
  <span class="Comment"># otherwise, real screen</span>
  height<span class="Special"> &lt;- </span>display-height
]

<span class="muRecipe">def</span> hide-cursor screen:&amp;:screen<span class="muRecipe"> -&gt; </span>screen:&amp;:screen [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  <span class="Comment"># if x exists (not real display), do nothing</span>
  <span class="Delimiter">{</span>
    <span class="muControl">break-unless</span> screen
    <span class="muControl">return</span>
  <span class="Delimiter">}</span>
  <span class="Comment"># otherwise, real screen</span>
  hide-cursor-on-display
]

<span class="muRecipe">def</span> show-cursor screen:&amp;:screen<span class="muRecipe"> -&gt; </span>screen:&amp;:screen [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  <span class="Comment"># if x exists (not real display), do nothing</span>
  <span class="Delimiter">{</span>
    <span class="muControl">break-unless</span> screen
    <span class="muControl">return</span>
  <span class="Delimiter">}</span>
  <span class="Comment"># otherwise, real screen</span>
  show-cursor-on-display
]

<span class="muRecipe">def</span> hide-screen screen:&amp;:screen<span class="muRecipe"> -&gt; </span>screen:&amp;:screen [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  <span class="Comment"># if x exists (not real display), do nothing</span>
  <span class="Comment"># todo: help test this</span>
  <span class="Delimiter">{</span>
    <span class="muControl">break-unless</span> screen
    <span class="muControl">return</span>
  <span class="Delimiter">}</span>
  <span class="Comment"># otherwise, real screen</span>
  hide-display
]

<span class="muRecipe">def</span> show-screen screen:&amp;:screen<span class="muRecipe"> -&gt; </span>screen:&amp;:screen [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  <span class="Comment"># if x exists (not real display), do nothing</span>
  <span class="Comment"># todo: help test this</span>
  <span class="Delimiter">{</span>
    <span class="muControl">break-unless</span> screen
    <span class="muControl">return</span>
  <span class="Delimiter">}</span>
  <span class="Comment"># otherwise, real screen</span>
  show-display
]

<span class="muRecipe">def</span> print screen:&amp;:screen, s:text<span class="muRecipe"> -&gt; </span>screen:&amp;:screen [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  color:num, color-found?:bool<span class="Special"> &lt;- </span><span class="Constant">next-ingredient</span>
  <span class="Delimiter">{</span>
    <span class="Comment"># default color to white</span>
    <span class="muControl">break-if</span> color-found?
    color<span class="Special"> &lt;- </span>copy <span class="Constant">7/white</span>
  <span class="Delimiter">}</span>
  bg-color:num, bg-color-found?:bool<span class="Special"> &lt;- </span><span class="Constant">next-ingredient</span>
  <span class="Delimiter">{</span>
    <span class="Comment"># default bg-color to black</span>
    <span class="muControl">break-if</span> bg-color-found?
    bg-color<span class="Special"> &lt;- </span>copy <span class="Constant">0/black</span>
  <span class="Delimiter">}</span>
  len:num<span class="Special"> &lt;- </span>length *s
  i:num<span class="Special"> &lt;- </span>copy <span class="Constant">0</span>
  <span class="Delimiter">{</span>
    done?:bool<span class="Special"> &lt;- </span>greater-or-equal i, len
    <span class="muControl">break-if</span> done?
    c:char<span class="Special"> &lt;- </span>index *s, i
    print screen, c, color, bg-color
    i<span class="Special"> &lt;- </span>add i, <span class="Constant">1</span>
    <span class="muControl">loop</span>
  <span class="Delimiter">}</span>
]

<span class="muScenario">scenario</span> print-text-stops-at-right-margin [
  <span class="Constant">local-scope</span>
  fake-screen:&amp;:screen<span class="Special"> &lt;- </span>new-fake-screen <span class="Constant">3/width</span>, <span class="Constant">2/height</span>
  run [
    fake-screen<span class="Special"> &lt;- </span>print fake-screen, <span class="Constant">[abcd]</span>
    cell:&amp;:@:screen-cell<span class="Special"> &lt;- </span>get *fake-screen, <span class="Constant">data:offset</span>
    <span class="Constant">10</span>:@:screen-cell/<span class="Special">raw &lt;- </span>copy *cell
  ]
  memory-should-contain [
    <span class="Constant">10</span><span class="Special"> &lt;- </span><span class="Constant">6</span>  <span class="Comment"># width*height</span>
    <span class="Constant">11</span><span class="Special"> &lt;- </span><span class="Constant">97</span>  <span class="Comment"># 'a'</span>
    <span class="Constant">12</span><span class="Special"> &lt;- </span><span class="Constant">7</span>  <span class="Comment"># white</span>
    <span class="Constant">13</span><span class="Special"> &lt;- </span><span class="Constant">98</span>  <span class="Comment"># 'b'</span>
    <span class="Constant">14</span><span class="Special"> &lt;- </span><span class="Constant">7</span>  <span class="Comment"># white</span>
    <span class="Constant">15</span><span class="Special"> &lt;- </span><span class="Constant">100</span>  <span class="Comment"># 'd' overwrites 'c'</span>
    <span class="Constant">16</span><span class="Special"> &lt;- </span><span class="Constant">7</span>  <span class="Comment"># white</span>
    <span class="Comment"># rest of screen is empty</span>
    <span class="Constant">17</span><span class="Special"> &lt;- </span><span class="Constant">0</span>
  ]
]

<span class="muRecipe">def</span> print-integer screen:&amp;:screen, n:num<span class="muRecipe"> -&gt; </span>screen:&amp;:screen [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  color:num, color-found?:bool<span class="Special"> &lt;- </span><span class="Constant">next-ingredient</span>
  <span class="Delimiter">{</span>
    <span class="Comment"># default color to white</span>
    <span class="muControl">break-if</span> color-found?
    color<span class="Special"> &lt;- </span>copy <span class="Constant">7/white</span>
  <span class="Delimiter">}</span>
  bg-color:num, bg-color-found?:bool<span class="Special"> &lt;- </span><span class="Constant">next-ingredient</span>
  <span class="Delimiter">{</span>
    <span class="Comment"># default bg-color to black</span>
    <span class="muControl">break-if</span> bg-color-found?
    bg-color<span class="Special"> &lt;- </span>copy <span class="Constant">0/black</span>
  <span class="Delimiter">}</span>
  <span class="Comment"># todo: other bases besides decimal</span>
  s:text<span class="Special"> &lt;- </span>to-text n
  screen<span class="Special"> &lt;- </span>print screen, s, color, bg-color
]

<span class="Comment"># for now, we can only print integers</span>
<span class="muRecipe">def</span> print screen:&amp;:screen, n:num<span class="muRecipe"> -&gt; </span>screen:&amp;:screen [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  color:num, color-found?:bool<span class="Special"> &lt;- </span><span class="Constant">next-ingredient</span>
  <span class="Delimiter">{</span>
    <span class="Comment"># default color to white</span>
    <span class="muControl">break-if</span> color-found?
    color<span class="Special"> &lt;- </span>copy <span class="Constant">7/white</span>
  <span class="Delimiter">}</span>
  bg-color:num, bg-color-found?:bool<span class="Special"> &lt;- </span><span class="Constant">next-ingredient</span>
  <span class="Delimiter">{</span>
    <span class="Comment"># default bg-color to black</span>
    <span class="muControl">break-if</span> bg-color-found?
    bg-color<span class="Special"> &lt;- </span>copy <span class="Constant">0/black</span>
  <span class="Delimiter">}</span>
  screen<span class="Special"> &lt;- </span>print-integer screen, n, color, bg-color
]

<span class="Comment"># addresses</span>
<span class="muRecipe">def</span> print screen:&amp;:screen, n:&amp;:_elem<span class="muRecipe"> -&gt; </span>screen:&amp;:screen [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  color:num, color-found?:bool<span class="Special"> &lt;- </span><span class="Constant">next-ingredient</span>
  <span class="Delimiter">{</span>
    <span class="Comment"># default color to white</span>
    <span class="muControl">break-if</span> color-found?
    color<span class="Special"> &lt;- </span>copy <span class="Constant">7/white</span>
  <span class="Delimiter">}</span>
  bg-color:num, bg-color-found?:bool<span class="Special"> &lt;- </span><span class="Constant">next-ingredient</span>
  <span class="Delimiter">{</span>
    <span class="Comment"># default bg-color to black</span>
    <span class="muControl">break-if</span> bg-color-found?
    bg-color<span class="Special"> &lt;- </span>copy <span class="Constant">0/black</span>
  <span class="Delimiter">}</span>
  n2:num<span class="Special"> &lt;- </span>copy n
  screen<span class="Special"> &lt;- </span>print-integer screen, n2, color, bg-color
]
</pre>
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