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LambdaFree is an analysis pass for the <a href="SXML">SXML</a> <a href="IntermediateLanguage">IntermediateLanguage</a>, invoked from <a href="ClosureConvert">ClosureConvert</a>. <h2 id="head-55f8ebc805e65b5b71ddafdae390e3be2bcd69af">Description</h2>
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This pass descends the entire <a href="SXML">SXML</a> program and attaches a property to each <tt>Lambda</tt> <tt>PrimExp.t</tt> in the program.  Then, you can use <tt>lambdaFree</tt> and <tt>lambdaRec</tt> to get free variables of that <tt>Lambda</tt>. 
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<h2 id="head-8781d615fd77be9578225c40ac67b9471394cced">Implementation</h2>

<a href = "http://mlton.org/cgi-bin/viewsvn.cgi/mlton/tags/on-20051202-release/mlton/closure-convert/lambda-free.sig?view=markup"><img src="moin-www.png" alt="[WWW]" height="11" width="11">lambda-free.sig</a>
 
<a href = "http://mlton.org/cgi-bin/viewsvn.cgi/mlton/tags/on-20051202-release/mlton/closure-convert/lambda-free.fun?view=markup"><img src="moin-www.png" alt="[WWW]" height="11" width="11">lambda-free.fun</a>
 <h2 id="head-35ec00231a68203708e39f0e2cc10b50c6bf62de">Details and Notes</h2>
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For <tt>Lambda</tt>s bound in a <tt>Fun</tt> dec, <tt>lambdaFree</tt> gives the union of the frees of the entire group of mutually recursive functions.  Hence, <tt>lambdaFree</tt> for every <tt>Lambda</tt> in a single <tt>Fun</tt> dec is the same. Furthermore, for a <tt>Lambda</tt> bound in a <tt>Fun</tt> dec, <tt>lambdaRec</tt> gives the list of other functions bound in the same dec defining that <tt>Lambda</tt>.  For example: 
<pre>val rec f = fn x =&gt; ... y ... g ... f ...
and g = fn z =&gt; ... f ... w ...
</pre>
<pre> * lambdaFree(fn x =&gt;) = [y, w]
 * lambdaFree(fn z =&gt;) = [y, w]
 * lambdaRec(fn x =&gt;) = [g, f]
 * lambdaRec(fn z =&gt;) = [f]
</pre>
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Last edited on 2005-12-02 04:21:28 by <span title="ppp-71-139-183-221.dsl.snfc21.pacbell.net"><a href="StephenWeeks">StephenWeeks</a></span>.
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