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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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<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>Mu - 064list.mu</title>
<meta name="Generator" content="Vim/7.4">
<meta name="plugin-version" content="vim7.4_v2">
<meta name="syntax" content="none">
<meta name="settings" content="use_css,pre_wrap,no_foldcolumn,expand_tabs,prevent_copy=">
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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"># A list links up multiple objects together to make them easier to manage.</span>
<span class="Comment">#</span>
<span class="Comment"># The objects must be of the same type. If you want to store multiple types in</span>
<span class="Comment"># a single list, use an exclusive-container.</span>

<span class="muData">container</span> list:_elem [
  value:_elem
  next:&amp;:list:_elem
]

<span class="muRecipe">def</span> push x:_elem, l:&amp;:list:_elem<span class="muRecipe"> -&gt; </span>l:&amp;:list:_elem [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  result:&amp;:list:_elem <span class="Special">&lt;-</span> new <span class="Delimiter">{</span>(list _elem): type<span class="Delimiter">}</span>
  *result <span class="Special">&lt;-</span> merge x, l
  <span class="muControl">reply</span> result
]

<span class="muRecipe">def</span> first in:&amp;:list:_elem<span class="muRecipe"> -&gt; </span>result:_elem [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  result <span class="Special">&lt;-</span> get *in, <span class="Constant">value:offset</span>
]

<span class="muRecipe">def</span> rest in:&amp;:list:_elem<span class="muRecipe"> -&gt; </span>result:&amp;:list:_elem/contained-in:in [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  result <span class="Special">&lt;-</span> get *in, <span class="Constant">next:offset</span>
]

<span class="muScenario">scenario</span> list-handling [
  run [
    <span class="Constant">local-scope</span>
    x:&amp;:list:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
    x <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, x
    x <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, x
    10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first x
    x <span class="Special">&lt;-</span> rest x
    11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first x
    x <span class="Special">&lt;-</span> rest x
    12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first x
    20:&amp;:list:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> rest x
  ]
  memory-should-contain [
   <span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>
   <span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
   <span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
   <span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># nothing left</span>
  ]
]

<span class="muRecipe">def</span> length l:&amp;:list:_elem<span class="muRecipe"> -&gt; </span>result:num [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  <span class="muControl">return-unless</span> l,<span class="Constant"> 0</span>
  rest:&amp;:list:_elem <span class="Special">&lt;-</span> rest l
  length-of-rest:num <span class="Special">&lt;-</span> length rest
  result <span class="Special">&lt;-</span> add length-of-rest,<span class="Constant"> 1</span>
]

<span class="Comment"># insert 'x' after 'in'</span>
<span class="muRecipe">def</span> insert x:_elem, in:&amp;:list:_elem<span class="muRecipe"> -&gt; </span>in:&amp;:list:_elem [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  new-node:&amp;:list:_elem <span class="Special">&lt;-</span> new <span class="Delimiter">{</span>(list _elem): type<span class="Delimiter">}</span>
  *new-node <span class="Special">&lt;-</span> put *new-node, <span class="Constant">value:offset</span>, x
  next-node:&amp;:list:_elem <span class="Special">&lt;-</span> get *in, <span class="Constant">next:offset</span>
  *in <span class="Special">&lt;-</span> put *in, <span class="Constant">next:offset</span>, new-node
  *new-node <span class="Special">&lt;-</span> put *new-node, <span class="Constant">next:offset</span>, next-node
]

<span class="muScenario">scenario</span> inserting-into-list [
  <span class="Constant">local-scope</span>
  list:&amp;:list:char <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
  list <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, list
  list <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, list
  run [
    list2:&amp;:list:char <span class="Special">&lt;-</span> rest list  <span class="Comment"># inside list</span>
    list2 <span class="Special">&lt;-</span> insert<span class="Constant"> 6</span>, list2
    <span class="Comment"># check structure</span>
    list2 <span class="Special">&lt;-</span> copy list
    10:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
    list2 <span class="Special">&lt;-</span> rest list2
    11:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
    list2 <span class="Special">&lt;-</span> rest list2
    12:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
    list2 <span class="Special">&lt;-</span> rest list2
    13:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
  ]
  memory-should-contain [
   <span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next</span>
   <span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
   <span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 6</span>  <span class="Comment"># inserted element</span>
   <span class="Constant"> 13</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
  ]
]

<span class="muScenario">scenario</span> inserting-at-end-of-list [
  <span class="Constant">local-scope</span>
  list:&amp;:list:char <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
  list <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, list
  list <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, list
  run [
    list2:&amp;:list:char <span class="Special">&lt;-</span> rest list  <span class="Comment"># inside list</span>
    list2 <span class="Special">&lt;-</span> rest list2  <span class="Comment"># now at end of list</span>
    list2 <span class="Special">&lt;-</span> insert<span class="Constant"> 6</span>, list2
    <span class="Comment"># check structure like before</span>
    list2 <span class="Special">&lt;-</span> copy list
    10:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
    list2 <span class="Special">&lt;-</span> rest list2
    11:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
    list2 <span class="Special">&lt;-</span> rest list2
    12:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
    list2 <span class="Special">&lt;-</span> rest list2
    13:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
  ]
  memory-should-contain [
   <span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next</span>
   <span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
   <span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
   <span class="Constant"> 13</span> <span class="Special">&lt;-</span><span class="Constant"> 6</span>  <span class="Comment"># inserted element</span>
  ]
]

<span class="muScenario">scenario</span> inserting-after-start-of-list [
  <span class="Constant">local-scope</span>
  list:&amp;:list:char <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
  list <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, list
  list <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, list
  run [
    list <span class="Special">&lt;-</span> insert<span class="Constant"> 6</span>, list
    <span class="Comment"># check structure like before</span>
    list2:&amp;:list:char <span class="Special">&lt;-</span> copy list
    10:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
    list2 <span class="Special">&lt;-</span> rest list2
    11:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
    list2 <span class="Special">&lt;-</span> rest list2
    12:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
    list2 <span class="Special">&lt;-</span> rest list2
    13:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
  ]
  memory-should-contain [
   <span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next</span>
   <span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 6</span>  <span class="Comment"># inserted element</span>
   <span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
   <span class="Constant"> 13</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
  ]
]

<span class="Comment"># remove 'x' from its surrounding list 'in'</span>
<span class="Comment">#</span>
<span class="Comment"># Returns null if and only if list is empty. Beware: in that case any other</span>
<span class="Comment"># pointers to the head are now invalid.</span>
<span class="muRecipe">def</span> remove x:&amp;:list:_elem/contained-in:in, in:&amp;:list:_elem<span class="muRecipe"> -&gt; </span>in:&amp;:list:_elem [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  <span class="Comment"># if 'x' is null, return</span>
  <span class="muControl">return-unless</span> x
  next-node:&amp;:list:_elem <span class="Special">&lt;-</span> rest x
  <span class="Comment"># clear next pointer of 'x'</span>
  *x <span class="Special">&lt;-</span> put *x, <span class="Constant">next:offset</span>,<span class="Constant"> 0</span>
  <span class="Comment"># if 'x' is at the head of 'in', return the new head</span>
  at-head?:bool <span class="Special">&lt;-</span> equal x, in
  <span class="muControl">return-if</span> at-head?, next-node
  <span class="Comment"># compute prev-node</span>
  prev-node:&amp;:list:_elem <span class="Special">&lt;-</span> copy in
  curr:&amp;:list:_elem <span class="Special">&lt;-</span> rest prev-node
  <span class="Delimiter">{</span>
    <span class="muControl">return-unless</span> curr
    found?:bool <span class="Special">&lt;-</span> equal curr, x
    <span class="muControl">break-if</span> found?
    prev-node <span class="Special">&lt;-</span> copy curr
    curr <span class="Special">&lt;-</span> rest curr
  <span class="Delimiter">}</span>
  <span class="Comment"># set its next pointer to skip 'x'</span>
  *prev-node <span class="Special">&lt;-</span> put *prev-node, <span class="Constant">next:offset</span>, next-node
]

<span class="muScenario">scenario</span> removing-from-list [
  <span class="Constant">local-scope</span>
  list:&amp;:list:char <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
  list <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, list
  list <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, list
  run [
    list2:&amp;:list:char <span class="Special">&lt;-</span> rest list  <span class="Comment"># second element</span>
    list <span class="Special">&lt;-</span> remove list2, list
    10:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal list2,<span class="Constant"> 0</span>
    <span class="Comment"># check structure like before</span>
    list2 <span class="Special">&lt;-</span> copy list
    11:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
    list2 <span class="Special">&lt;-</span> rest list2
    12:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
    20:&amp;:list:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> rest list2
  ]
  memory-should-contain [
   <span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># remove returned non-null</span>
   <span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next, skipping deleted element</span>
   <span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
   <span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># no more elements</span>
  ]
]

<span class="muScenario">scenario</span> removing-from-start-of-list [
  <span class="Constant">local-scope</span>
  list:&amp;:list:char <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
  list <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, list
  list <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, list
  run [
    list <span class="Special">&lt;-</span> remove list, list
    <span class="Comment"># check structure like before</span>
    list2:&amp;:list:char <span class="Special">&lt;-</span> copy list
    10:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
    list2 <span class="Special">&lt;-</span> rest list2
    11:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
    20:&amp;:list:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> rest list2
  ]
  memory-should-contain [
   <span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>  <span class="Comment"># scanning next, skipping deleted element</span>
   <span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
   <span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># no more elements</span>
  ]
]

<span class="muScenario">scenario</span> removing-from-end-of-list [
  <span class="Constant">local-scope</span>
  list:&amp;:list:char <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
  list <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, list
  list <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, list
  run [
    <span class="Comment"># delete last element</span>
    list2:&amp;:list:char <span class="Special">&lt;-</span> rest list
    list2 <span class="Special">&lt;-</span> rest list2
    list <span class="Special">&lt;-</span> remove list2, list
    10:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal list2,<span class="Constant"> 0</span>
    <span class="Comment"># check structure like before</span>
    list2 <span class="Special">&lt;-</span> copy list
    11:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
    list2 <span class="Special">&lt;-</span> rest list2
    12:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
    20:&amp;:list:char/<span class="Special">raw</span> <span class="Special">&lt;-</span> rest list2
  ]
  memory-should-contain [
   <span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># remove returned non-null</span>
   <span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next, skipping deleted element</span>
   <span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
   <span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># no more elements</span>
  ]
]

<span class="muScenario">scenario</span> removing-from-singleton-list [
  <span class="Constant">local-scope</span>
  list:&amp;:list:char <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
  run [
    list <span class="Special">&lt;-</span> remove list, list
    1:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> copy list
  ]
  memory-should-contain [
   <span class="Constant"> 1</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># back to an empty list</span>
  ]
]

<span class="Comment"># reverse the elements of a list</span>
<span class="Comment"># (contributed by Caleb Couch)</span>
<span class="muRecipe">def</span> reverse list:&amp;:list:_elem temp:&amp;:list:_elem/contained-in:result<span class="muRecipe"> -&gt; </span>result:&amp;:list:_elem [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  <span class="muControl">reply-unless</span> list, temp
  object:_elem <span class="Special">&lt;-</span> first, list
  list <span class="Special">&lt;-</span> rest list
  temp <span class="Special">&lt;-</span> push object, temp
  result <span class="Special">&lt;-</span> reverse list, temp
]

<span class="muScenario">scenario</span> reverse-list [
  <span class="Constant">local-scope</span>
  list:&amp;:list:number <span class="Special">&lt;-</span> push<span class="Constant"> 1</span>,<span class="Constant"> 0</span>
  list <span class="Special">&lt;-</span> push<span class="Constant"> 2</span>, list
  list <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>, list
  run [
    stash <span class="Constant">[list:]</span>, list
    list <span class="Special">&lt;-</span> reverse list
    stash <span class="Constant">[reversed:]</span>, list
  ]
  trace-should-contain [
    app: list:<span class="Constant"> 3</span><span class="muRecipe"> -&gt; </span>2<span class="muRecipe"> -&gt; </span>1
    app: reversed:<span class="Constant"> 1</span><span class="muRecipe"> -&gt; </span>2<span class="muRecipe"> -&gt; </span>3
  ]
]

<span class="muRecipe">def</span> to-text in:&amp;:list:_elem<span class="muRecipe"> -&gt; </span>result:text [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  buf:&amp;:buffer <span class="Special">&lt;-</span> new-buffer<span class="Constant"> 80</span>
  buf <span class="Special">&lt;-</span> to-buffer in, buf
  result <span class="Special">&lt;-</span> buffer-to-array buf
]

<span class="Comment"># variant of 'to-text' which stops printing after a few elements (and so is robust to cycles)</span>
<span class="muRecipe">def</span> to-text-line in:&amp;:list:_elem<span class="muRecipe"> -&gt; </span>result:text [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  buf:&amp;:buffer <span class="Special">&lt;-</span> new-buffer<span class="Constant"> 80</span>
  buf <span class="Special">&lt;-</span> to-buffer in, buf,<span class="Constant"> 6</span>  <span class="Comment"># max elements to display</span>
  result <span class="Special">&lt;-</span> buffer-to-array buf
]

<span class="muRecipe">def</span> to-buffer in:&amp;:list:_elem, buf:&amp;:buffer<span class="muRecipe"> -&gt; </span>buf:&amp;:buffer [
  <span class="Constant">local-scope</span>
  <span class="Constant">load-ingredients</span>
  <span class="Delimiter">{</span>
    <span class="muControl">break-if</span> in
    buf <span class="Special">&lt;-</span> append buf, <span class="Constant">[[]</span>]
    <span class="muControl">return</span>
  <span class="Delimiter">}</span>
  <span class="Comment"># append in.value to buf</span>
  val:_elem <span class="Special">&lt;-</span> get *in, <span class="Constant">value:offset</span>
  buf <span class="Special">&lt;-</span> append buf, val
  <span class="Comment"># now prepare next</span>
  next:&amp;:list:_elem <span class="Special">&lt;-</span> rest in
  nextn:num <span class="Special">&lt;-</span> copy next
  <span class="muControl">return-unless</span> next
  buf <span class="Special">&lt;-</span> append buf, <span class="Constant">[ -&gt; ]</span>
  <span class="Comment"># and recurse</span>
  remaining:num, optional-ingredient-found?:bool <span class="Special">&lt;-</span> <span class="Constant">next-ingredient</span>
  <span class="Delimiter">{</span>
    <span class="muControl">break-if</span> optional-ingredient-found?
    <span class="Comment"># unlimited recursion</span>
    buf <span class="Special">&lt;-</span> to-buffer next, buf
    <span class="muControl">return</span>
  <span class="Delimiter">}</span>
  <span class="Delimiter">{</span>
    <span class="muControl">break-unless</span> remaining
    <span class="Comment"># limited recursion</span>
    remaining <span class="Special">&lt;-</span> subtract remaining,<span class="Constant"> 1</span>
    buf <span class="Special">&lt;-</span> to-buffer next, buf, remaining
    <span class="muControl">return</span>
  <span class="Delimiter">}</span>
  <span class="Comment"># past recursion depth; insert ellipses and stop</span>
  append buf, <span class="Constant">[...]</span>
]

<span class="muScenario">scenario</span> stash-empty-list [
  <span class="Constant">local-scope</span>
  x:&amp;:list:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
  run [
    stash x
  ]
  trace-should-contain [
    app: <span class="Constant">[]</span>
  ]
]
</pre>
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