doc/guide/localhost/XMLSimplifyTypes

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  26 <h1>XMLSimplifyTypes</h1>
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  29 <div id="preamble">
  30 <div class="sectionbody">
  31 <div class="paragraph"><p><a href="XMLSimplifyTypes">XMLSimplifyTypes</a> is an optimization pass for the <a href="XML">XML</a>
  32 <a href="IntermediateLanguage">IntermediateLanguage</a>, invoked from <a href="XMLSimplify">XMLSimplify</a>.</p></div>
  33 </div>
  34 </div>
  35 <div class="sect1">
  36 <h2 id="_description">Description</h2>
  37 <div class="sectionbody">
  38 <div class="paragraph"><p>This pass simplifies types in an <a href="XML">XML</a> program, eliminating all
  39 unused type arguments.</p></div>
  40 </div>
  41 </div>
  42 <div class="sect1">
  43 <h2 id="_implementation">Implementation</h2>
  44 <div class="sectionbody">
  45 <div class="ulist"><ul>
  46 <li>
  47 <p>
  48 <a href="https://github.com/MLton/mlton/blob/master/mlton/xml/simplify-types.sig"><span class="monospaced">simplify-types.sig</span></a>
  49 </p>
  50 </li>
  51 <li>
  52 <p>
  53 <a href="https://github.com/MLton/mlton/blob/master/mlton/xml/simplify-types.fun"><span class="monospaced">simplify-types.fun</span></a>
  54 </p>
  55 </li>
  56 </ul></div>
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  58 </div>
  59 <div class="sect1">
  60 <h2 id="_details_and_notes">Details and Notes</h2>
  61 <div class="sectionbody">
  62 <div class="paragraph"><p>It first computes a simple fixpoint on all the <span class="monospaced">datatype</span> declarations
  63 to determine which <span class="monospaced">datatype</span> <span class="monospaced">tycon</span> args are actually used.  Then it
  64 does a single pass over the program to determine which polymorphic
  65 declaration type variables are used, and rewrites types to eliminate
  66 unused type arguments.</p></div>
  67 <div class="paragraph"><p>This pass should eliminate any spurious duplication that the
  68 <a href="Monomorphise">Monomorphise</a> pass might perform due to phantom types.</p></div>
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