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<a href="./Home">MLton 20201002</a>
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<h1>MLtonCont</h1>
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<div id="content">
<div id="preamble">
<div class="sectionbody">
<div class="listingblock">
<div class="content"><div class="highlight"><pre><span></span><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>
<span class="w">   </span><span class="k">sig</span><span class="w"></span>
<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>

<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>
<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>
<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>
<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>
<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>
<span class="w">   </span><span class="k">end</span><span class="w"></span>
</pre></div></div></div>
<div class="ulist"><ul>
<li>
<p>
<span class="monospaced">type 'a t</span>
</p>
<div class="paragraph"><p>the type of continuations that expect a value of type <span class="monospaced">'a</span>.</p></div>
</li>
<li>
<p>
<span class="monospaced">callcc f</span>
</p>
<div class="paragraph"><p>applies <span class="monospaced">f</span> to the current continuation.  This copies the entire
stack; hence, <span class="monospaced">callcc</span> takes time proportional to the size of the
current stack.</p></div>
</li>
<li>
<p>
<span class="monospaced">isolate f</span>
</p>
<div class="paragraph"><p>creates a continuation that evaluates <span class="monospaced">f</span> in an empty context.  This
is a constant time operation, and yields a constant size stack.</p></div>
</li>
<li>
<p>
<span class="monospaced">prepend (k, f)</span>
</p>
<div class="paragraph"><p>composes a function <span class="monospaced">f</span> with a continuation <span class="monospaced">k</span> to create a
continuation that first does <span class="monospaced">f</span> and then does <span class="monospaced">k</span>.  This is a
constant time operation.</p></div>
</li>
<li>
<p>
<span class="monospaced">throw (k, v)</span>
</p>
<div class="paragraph"><p>throws value <span class="monospaced">v</span> to continuation <span class="monospaced">k</span>.  This copies the entire stack of
<span class="monospaced">k</span>; hence, <span class="monospaced">throw</span> takes time proportional to the size of this stack.</p></div>
</li>
<li>
<p>
<span class="monospaced">throw' (k, th)</span>
</p>
<div class="paragraph"><p>a generalization of throw that evaluates <span class="monospaced">th ()</span> in the context of
<span class="monospaced">k</span>.  Thus, for example, if <span class="monospaced">th ()</span> raises an exception or captures
another continuation, it will see <span class="monospaced">k</span>, not the current continuation.</p></div>
</li>
</ul></div>
</div>
</div>
<div class="sect1">
<h2 id="_also_see">Also see</h2>
<div class="sectionbody">
<div class="ulist"><ul>
<li>
<p>
<a href="MLtonContIsolateImplementation">MLtonContIsolateImplementation</a>
</p>
</li>
</ul></div>
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