18498c43d2
git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@576 b08c6af1-5177-4d33-ba66-4b1c6b8b522a
84 lines
2.5 KiB
HTML
84 lines
2.5 KiB
HTML
<?xml version="1.0" encoding="iso-8859-1"?>
|
|
<?xml-stylesheet type="text/css" href="../../styles.css" ?>
|
|
|
|
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
|
|
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
|
|
|
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
|
|
|
|
<head>
|
|
<title>retract/1</title>
|
|
<link rel="stylesheet" href="../../styles.css" type="text/css" />
|
|
</head>
|
|
|
|
<body>
|
|
|
|
<hr />
|
|
<h2><code><a class="back" title="Return to index" href="../index.html#retract1">retract/1</a></code></h2>
|
|
<hr />
|
|
|
|
<h4>Description</h4>
|
|
|
|
<blockquote>
|
|
<pre>
|
|
retract(Clause)
|
|
retract((Head:-Body))
|
|
</pre>
|
|
<p>
|
|
Retracts a dynamic clause from an object.
|
|
</p>
|
|
</blockquote>
|
|
|
|
<h4>Template and modes</h4>
|
|
|
|
<blockquote>
|
|
<pre>
|
|
retract(+clause)
|
|
</pre>
|
|
</blockquote>
|
|
|
|
<h4>Errors</h4>
|
|
|
|
<blockquote>
|
|
<dl>
|
|
<dt>Head is a variable:</dt>
|
|
<dd><code>instantiation_error</code></dd>
|
|
<dt>Head is neither a variable nor a callable term:</dt>
|
|
<dd><code>type_error(callable, Head)</code></dd>
|
|
<dt>The predicate indicator of Head is that of a private predicate:</dt>
|
|
<dd><code>permission_error(modify, private_predicate, Head)</code></dd>
|
|
<dt>The predicate indicator of Head is that of a protected predicate:</dt>
|
|
<dd><code>permission_error(modify, protected_predicate, Head)</code></dd>
|
|
<dt>The predicate indicator of Head is that of a static predicate:</dt>
|
|
<dd><code>permission_error(modify, static_predicate, Head)</code></dd>
|
|
<dt>The predicate indicator of Head is not declared:</dt>
|
|
<dd><code>existence_error(predicate_declaration, Head)</code></dd>
|
|
</dl>
|
|
</blockquote>
|
|
|
|
<h4>Examples</h4>
|
|
|
|
<blockquote>
|
|
<dl>
|
|
<dt>To retract a matching clause of any dynamic predicate in <a class="glossary" title="Go to glossary definition" href="../../glossary.html#this">this</a>:</dt>
|
|
<dd><code>retract(Clause)</code></dd>
|
|
<dt>To retract a matching clause of a public or protected dynamic predicate in <a class="glossary" title="Go to glossary definition" href="../../glossary.html#self">self</a>:</dt>
|
|
<dd><code>::retract(Clause)</code></dd>
|
|
<dt>To retract a matching clause of a public dynamic predicate in an object:</dt>
|
|
<dd><code>Object::retract(Clause)</code></dd>
|
|
</dl>
|
|
</blockquote>
|
|
|
|
<hr />
|
|
<p class="center">
|
|
<strong><a href="clause2.html">Previous</a> | <a href="retractall1.html">Next</a> | <a href="../index.html">Table of Contents</a> | <a href="../../bibliography.html">Bibliography</a> | <a href="../../glossary.html">Glossary</a></strong>
|
|
</p>
|
|
<p class="center">
|
|
Last updated on: August 6, 2002
|
|
</p>
|
|
<hr />
|
|
|
|
</body>
|
|
|
|
</html>
|