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<a href="./Home">MLton 20201002</a>
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<h1>MLLex</h1>
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<div id="content">
<div id="preamble">
<div class="sectionbody">
<div class="paragraph"><p><a href="MLLex">MLLex</a> is a lexical analyzer generator for <a href="StandardML">Standard ML</a>
modeled after the Lex lexical analyzer generator.</p></div>
<div class="paragraph"><p>A version of MLLex, ported from the <a href="SMLNJ">SML/NJ</a> sources, is
distributed with MLton.</p></div>
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<div class="sect1">
<h2 id="_description">Description</h2>
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<div class="paragraph"><p>MLLex takes as input the lex language as defined in the ML-Lex manual,
and outputs a lexical analyzer in SML.</p></div>
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<div class="sect1">
<h2 id="_implementation">Implementation</h2>
<div class="sectionbody">
<div class="ulist"><ul>
<li>
<p>
<a href="https://github.com/MLton/mlton/blob/master/mllex/lexgen.sml"><span class="monospaced">lexgen.sml</span></a>
</p>
</li>
<li>
<p>
<a href="https://github.com/MLton/mlton/blob/master/mllex/main.sml"><span class="monospaced">main.sml</span></a>
</p>
</li>
<li>
<p>
<a href="https://github.com/MLton/mlton/blob/master/mllex/call-main.sml"><span class="monospaced">call-main.sml</span></a>
</p>
</li>
</ul></div>
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<div class="sect1">
<h2 id="_details_and_notes">Details and Notes</h2>
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<div class="paragraph"><p>There are 3 main passes in the MLLex tool:</p></div>
<div class="ulist"><ul>
<li>
<p>
Source parsing. In this pass, lex source program are parsed into internal representations. The core part of this pass is a hand-written lexer and an LL(1) parser. The output of this pass is a record of user code, rules (along with start states) and actions. (MLLex definitions are wiped off.)
</p>
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<li>
<p>
DFA construction. In this pass, a DFA is constructed by the algorithm of H. Yamada et. al.
</p>
</li>
<li>
<p>
Output. In this pass, the generated DFA is written out as a transition table, along with a table-driven algorithm, to an SML file.
</p>
</li>
</ul></div>
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<div class="sect1">
<h2 id="_also_see">Also see</h2>
<div class="sectionbody">
<div class="ulist"><ul>
<li>
<p>
<a href="Documentation.attachments/mllex.pdf"><span class="monospaced">mllex.pdf</span></a>
</p>
</li>
<li>
<p>
<a href="MLYacc">MLYacc</a>
</p>
</li>
<li>
<p>
<a href="References#AppelEtAl94">AppelEtAl94</a>
</p>
</li>
<li>
<p>
<a href="References#Price09">Price09</a>
</p>
</li>
</ul></div>
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