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<title>ImplementSuffix - MLton Standard ML Compiler (SML Compiler)</title>
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      <a class = mltona href="Home">MLton 20051202</a>
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      ImplementSuffix
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ImplementSuffix is a pass for the <a href="SXML">SXML</a> <a href="IntermediateLanguage">IntermediateLanguage</a>, invoked from <a href="SXMLSimplify">SXMLSimplify</a>. <h2 id="head-55f8ebc805e65b5b71ddafdae390e3be2bcd69af">Description</h2>
<p>
This pass implements the <tt>TopLevel_setSuffix</tt> primitive, which installs a function to exit the program. 
</p>
<h2 id="head-8781d615fd77be9578225c40ac67b9471394cced">Implementation</h2>

<a href = "http://mlton.org/cgi-bin/viewsvn.cgi/mlton/tags/on-20051202-release/mlton/xml/implement-suffix.sig?view=markup"><img src="moin-www.png" alt="[WWW]" height="11" width="11">implement-suffix.sig</a>
 
<a href = "http://mlton.org/cgi-bin/viewsvn.cgi/mlton/tags/on-20051202-release/mlton/xml/implement-suffix.fun?view=markup"><img src="moin-www.png" alt="[WWW]" height="11" width="11">implement-suffix.fun</a>
 <h2 id="head-35ec00231a68203708e39f0e2cc10b50c6bf62de">Details and Notes</h2>
<p>
ImplementSuffix works by introducing a new <tt>ref</tt> cell to contain the function of type <tt>unit&nbsp;-&gt;&nbsp;unit</tt> that should be called on program exit. 
</p>

    <ul>

    <li>
<p>
 The following code (appropriately alpha-converted) is appended to the beginning of the <a href="SXML">SXML</a> program: 
<pre>    val z_0 = 
      fn a_0 =&gt; 
      let
         val x_0 = 
            "toplevel suffix not installed"
         val x_1 = 
            MLton_bug (x_0)
      in
         x_1
      end
   val topLevelSuffixCell = 
      Ref_ref (z_0)
</pre>
</p>
</li>
    <li>
<p>
 Any occurrence of 
<pre>   val x_0 = 
      TopLevel_setSuffix (f_0)
</pre> is rewritten to 
<pre>   val x_0 = 
      Ref_assign (topLevelSuffixCell, f_0)
</pre>
</p>
</li>
    <li>
<p>
 The following code (appropriately alpha-converted) is appended to the end of the <a href="SXML">SXML</a> program: 
<pre>   val f_0 = 
      Ref_deref (topLevelSuffixCell)
   val z_0 = 
      ()
   val x_0 = 
      f_0 z_0
</pre>
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<p>
<hr>
Last edited on 2005-12-02 04:20:49 by <span title="ppp-71-139-183-221.dsl.snfc21.pacbell.net"><a href="StephenWeeks">StephenWeeks</a></span>.
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