doc/guide/localhost/MLtonCont

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  22 <a href="./Home">MLton 20180207</a>
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  26 <h1>MLtonCont</h1>
  27 </div>
  28 <div id="content">
  29 <div id="preamble">
  30 <div class="sectionbody">
  31 <div class="listingblock">
  32 <div class="content"><div class="highlight"><pre><span class="k">signature</span><span class="w"> </span><span class="n">MLTON_CONT</span><span class="w"> </span><span class="p">=</span><span class="w"></span>
  33 <span class="w">   </span><span class="k">sig</span><span class="w"></span>
  34 <span class="w">      </span><span class="k">type</span><span class="w"> </span><span class="n">&#39;a</span><span class="w"> </span><span class="n">t</span><span class="w"></span>
  35
  36 <span class="w">      </span><span class="k">val</span><span class="w"> </span><span class="n">callcc</span><span class="p">:</span><span class="w"> </span><span class="p">(</span><span class="n">&#39;a</span><span class="w"> </span><span class="n">t</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">&#39;a</span><span class="p">)</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">&#39;a</span><span class="w"></span>
  37 <span class="w">      </span><span class="k">val</span><span class="w"> </span><span class="n">isolate</span><span class="p">:</span><span class="w"> </span><span class="p">(</span><span class="n">&#39;a</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">unit</span><span class="p">)</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">&#39;a</span><span class="w"> </span><span class="n">t</span><span class="w"></span>
  38 <span class="w">      </span><span class="k">val</span><span class="w"> </span><span class="n">prepend</span><span class="p">:</span><span class="w"> </span><span class="n">&#39;a</span><span class="w"> </span><span class="n">t</span><span class="w"> </span><span class="n">*</span><span class="w"> </span><span class="p">(</span><span class="n">&#39;b</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">&#39;a</span><span class="p">)</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">&#39;b</span><span class="w"> </span><span class="n">t</span><span class="w"></span>
  39 <span class="w">      </span><span class="k">val</span><span class="w"> </span><span class="n">throw</span><span class="p">:</span><span class="w"> </span><span class="n">&#39;a</span><span class="w"> </span><span class="n">t</span><span class="w"> </span><span class="n">*</span><span class="w"> </span><span class="n">&#39;a</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">&#39;b</span><span class="w"></span>
  40 <span class="w">      </span><span class="k">val</span><span class="w"> </span><span class="n">throw&#39;</span><span class="p">:</span><span class="w"> </span><span class="n">&#39;a</span><span class="w"> </span><span class="n">t</span><span class="w"> </span><span class="n">*</span><span class="w"> </span><span class="p">(</span><span class="n">unit</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">&#39;a</span><span class="p">)</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">&#39;b</span><span class="w"></span>
  41 <span class="w">   </span><span class="k">end</span><span class="w"></span>
  42 </pre></div></div></div>
  43 <div class="ulist"><ul>
  44 <li>
  45 <p>
  46 <span class="monospaced">type 'a t</span>
  47 </p>
  48 <div class="paragraph"><p>the type of continuations that expect a value of type <span class="monospaced">'a</span>.</p></div>
  49 </li>
  50 <li>
  51 <p>
  52 <span class="monospaced">callcc f</span>
  53 </p>
  54 <div class="paragraph"><p>applies <span class="monospaced">f</span> to the current continuation.  This copies the entire
  55 stack; hence, <span class="monospaced">callcc</span> takes time proportional to the size of the
  56 current stack.</p></div>
  57 </li>
  58 <li>
  59 <p>
  60 <span class="monospaced">isolate f</span>
  61 </p>
  62 <div class="paragraph"><p>creates a continuation that evaluates <span class="monospaced">f</span> in an empty context.  This
  63 is a constant time operation, and yields a constant size stack.</p></div>
  64 </li>
  65 <li>
  66 <p>
  67 <span class="monospaced">prepend (k, f)</span>
  68 </p>
  69 <div class="paragraph"><p>composes a function <span class="monospaced">f</span> with a continuation <span class="monospaced">k</span> to create a
  70 continuation that first does <span class="monospaced">f</span> and then does <span class="monospaced">k</span>.  This is a
  71 constant time operation.</p></div>
  72 </li>
  73 <li>
  74 <p>
  75 <span class="monospaced">throw (k, v)</span>
  76 </p>
  77 <div class="paragraph"><p>throws value <span class="monospaced">v</span> to continuation <span class="monospaced">k</span>.  This copies the entire stack of
  78 <span class="monospaced">k</span>; hence, <span class="monospaced">throw</span> takes time proportional to the size of this stack.</p></div>
  79 </li>
  80 <li>
  81 <p>
  82 <span class="monospaced">throw' (k, th)</span>
  83 </p>
  84 <div class="paragraph"><p>a generalization of throw that evaluates <span class="monospaced">th ()</span> in the context of
  85 <span class="monospaced">k</span>.  Thus, for example, if <span class="monospaced">th ()</span> raises an exception or captures
  86 another continuation, it will see <span class="monospaced">k</span>, not the current continuation.</p></div>
  87 </li>
  88 </ul></div>
  89 </div>
  90 </div>
  91 <div class="sect1">
  92 <h2 id="_also_see">Also see</h2>
  93 <div class="sectionbody">
  94 <div class="ulist"><ul>
  95 <li>
  96 <p>
  97 <a href="MLtonContIsolateImplementation">MLtonContIsolateImplementation</a>
  98 </p>
  99 </li>
 100 </ul></div>
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