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<p>For a tutorial for writing rules, see <a href="guide.html">guide</a>.  For a detailed reference of the language, see <a href="reference.html">reference</a>.  For details on the modules, see <a href="modules.html">modules</a>.</p>
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<h2 id="_introduction">Introduction</h2>
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<p>The Predicate Rule system provides an alternative rule injection system fo