67 lines
2.8 KiB
HTML
67 lines
2.8 KiB
HTML
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<?xml version="1.0" encoding="utf-8"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
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"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
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<head>
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<meta http-equiv="content-type" content="application/xml+xhtml; charset=utf-8" />
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<title>Logtalk built-in method: expand_term/2</title>
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<link rel="stylesheet" href="../../screen.css" type="text/css" media="screen"/>
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<link rel="stylesheet" href="../../print.css" type="text/css" media="print"/>
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</head>
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<body>
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<div class="top-left">Logtalk reference manual</div>
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<div class="top-right">Built-in method: expand_term/2</div>
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<div class="bottom-left"><span class="page"/></div>
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<div class="bottom-right"><span class="page"/></div>
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<div class="navtop"><a href="../../index.html">contents</a> > <a href="../index.html">reference manual</a> > <a href="../index.html#methods">built-in methods</a></div>
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<h2 class="code">expand_term/2</h2>
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<h4>Description</h4>
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<pre>expand_term(Term, Expansion)</pre>
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<p>
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Expands a term. The most common use is to expand a grammar rule into a clause. Users may override the default Logtalk grammar rule translator by defining clauses for the predicate <a href="term_expansion2.html"><code>term_expansion/2</code></a>.
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<p>
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</p>
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The expansion works as follows: if the first argument is a variable, then it is unified with the second argument; if the first argument is not a variable and clauses for the <code>term_expansion/2</code> predicate are within scope, then this predicate is called to provide an expansion that is then unified with the second argument; if the <code>term_expansion/2</code> predicate is not used and the first argument is a compound term with functor <code>-->/2</code> then the default Logtalk grammar rule translator is used, with the resulting clause being unified with the second argument; when the translator is not used, the two arguments are unified.
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</p>
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<p>
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This built-in method may be used to expand a grammar rule into a clause for use with the built-in database methods.
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</p>
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<h4>Template and modes</h4>
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<pre>expand_term(?term, ?term)</pre>
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<h4>Errors</h4>
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<dl class="errors">
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<dt>(none)</dt>
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</dl>
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<h4>Examples</h4>
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<blockquote>
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<dl>
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<dt>(none)</dt>
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</dl>
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</blockquote>
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<div class="footer">
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<div class="navbottom"><a href="../index.html#methods">previous</a> | <a href="../../glossary.html">glossary</a> | <a href="term_expansion2.html">next</a></div>
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<div class="copyright">Copyright © <a href="mailto:pmoura@logtalk.org">Paulo Moura</a> — <a href="http://www.logtalk.org">Logtalk.org</a></div>
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<div class="footnote">
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<span class="validators"><a href="http://validator.w3.org/check/referer">XHTML</a> + <a href="http://jigsaw.w3.org/css-validator/check/referer">CSS</a></span>
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<span class="date">Last updated on: January 29, 2006</span>
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</div>
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</div>
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</body>
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</html>
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