yap-6.3/Logtalk/manuals/refman/methods/parameter2.html

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	<title>parameter/2</title>
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<h2><code><a class="back" title="Return to index" href="../index.html#parameter2">parameter/2</a></code></h2>
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<h4>Description</h4>

<blockquote>
<pre>
parameter(Number, Term)
</pre>
<p>
	Used only in <a class="glossary" title="Go to glossary definition" href="../../glossary.html#parametric">parametric objects</a>, this method returns parameter values by using the parameter position in the entity identifier. Note that this predicate implies an instantiation between its second argument and the corresponding implicit context argument in the predicate containing the call. This instantiation occurs at the clause head, not at the clause body. See also <a  href="this1.html"><code>this/1</code></a>.
</p>
</blockquote>

<h4>Template and modes</h4>

<blockquote>
<pre>
parameter(+integer, ?term)
</pre>
</blockquote>

<h4>Errors</h4>

<blockquote>
	<dl>
		<dt>Number is a variable:</dt>
			<dd><code>instantiation_error</code></dd>
		<dt>Number is neither a variable nor an integer value:</dt>
			<dd><code>type_error(integer, Number)</code></dd>
		<dt>Object identifier is not a compound term:</dt>
			<dd><code>type_error(compound, Object)</code></dd>
		<dt>Number is a negative integer value:</dt>
			<dd><code>domain_error(not_less_than_zero, Number)</code></dd>
	</dl>
</blockquote>

<h4>Examples</h4>

<blockquote>
<pre>
:- object(box(_Colour)).

    ...
    
    colour(Colour) :-
        parameter(1, Colour).

    ...
</pre>
</blockquote>

<hr />
<p class="center">
<strong><a href="../builtins/retractall1.html">Previous</a> | <a href="self1.html">Next</a> | <a href="../index.html">Table of Contents</a> | <a href="../../bibliography.html">Bibliography</a> | <a href="../../glossary.html">Glossary</a></strong>
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Last updated on: March 4, 2003
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Logtalk release 2.14.1 files. git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@561 b08c6af1-5177-4d33-ba66-4b1c6b8b522a 2002-08-01 00:34:42 +01:00			`<?xml version="1.0" encoding="iso-8859-1"?>`
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Logtalk release 2.14.1 files. git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@561 b08c6af1-5177-4d33-ba66-4b1c6b8b522a 2002-08-01 00:34:42 +01:00			`<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"`
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			`<head>`
			`<title>parameter/2</title>`
Logtalk 2.14.2 release files. git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@576 b08c6af1-5177-4d33-ba66-4b1c6b8b522a 2002-08-26 17:45:50 +01:00			`<link rel="stylesheet" href="../../styles.css" type="text/css" />`
Logtalk files git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@55 b08c6af1-5177-4d33-ba66-4b1c6b8b522a 2001-06-06 21:07:01 +01:00			`</head>`

			`<body>`

			`<hr />`
			`<h2><code><a class="back" title="Return to index" href="../index.html#parameter2">parameter/2</a></code></h2>`
			`<hr />`

			`<h4>Description</h4>`

			`<blockquote>`
			`<pre>`
			`parameter(Number, Term)`
			`</pre>`
			`<p>`
Logtalk 2.15.1 release files. git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@791 b08c6af1-5177-4d33-ba66-4b1c6b8b522a 2003-03-08 10:01:36 +00:00			Used only in <a class="glossary" title="Go to glossary definition" href="../../glossary.html#parametric">parametric objects</a>, this method returns parameter values by using the parameter position in the entity identifier. Note that this predicate implies an instantiation between its second argument and the corresponding implicit context argument in the predicate containing the call. This instantiation occurs at the clause head, not at the clause body. See also <a href="this1.html"><code>this/1</code></a>.
Logtalk files git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@55 b08c6af1-5177-4d33-ba66-4b1c6b8b522a 2001-06-06 21:07:01 +01:00			`</p>`
			`</blockquote>`

			`<h4>Template and modes</h4>`

			`<blockquote>`
			`<pre>`
			`parameter(+integer, ?term)`
			`</pre>`
			`</blockquote>`

Updated to Logtalk 2.9.1 git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@211 b08c6af1-5177-4d33-ba66-4b1c6b8b522a 2001-12-05 23:57:48 +00:00			`<h4>Errors</h4>`
Logtalk files git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@55 b08c6af1-5177-4d33-ba66-4b1c6b8b522a 2001-06-06 21:07:01 +01:00
			`<blockquote>`
			`<dl>`
			`<dt>Number is a variable:</dt>`
			`<dd><code>instantiation_error</code></dd>`
Logtalk 2.14.2 release files. git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@576 b08c6af1-5177-4d33-ba66-4b1c6b8b522a 2002-08-26 17:45:50 +01:00			`<dt>Number is neither a variable nor an integer value:</dt>`
Logtalk files git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@55 b08c6af1-5177-4d33-ba66-4b1c6b8b522a 2001-06-06 21:07:01 +01:00			`<dd><code>type_error(integer, Number)</code></dd>`
			`<dt>Object identifier is not a compound term:</dt>`
			`<dd><code>type_error(compound, Object)</code></dd>`
			`<dt>Number is a negative integer value:</dt>`
			`<dd><code>domain_error(not_less_than_zero, Number)</code></dd>`
			`</dl>`
			`</blockquote>`

			`<h4>Examples</h4>`

			`<blockquote>`
			`<pre>`
			`:- object(box(_Colour)).`

			`...`

			`colour(Colour) :-`
			`parameter(1, Colour).`

			`...`
			`</pre>`
			`</blockquote>`

			`<hr />`
			`<p class="center">`
			`<strong><a href="../builtins/retractall1.html">Previous</a> \| <a href="self1.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">`
Logtalk 2.15.1 release files. git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@791 b08c6af1-5177-4d33-ba66-4b1c6b8b522a 2003-03-08 10:01:36 +00:00			`Last updated on: March 4, 2003`
Logtalk files git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@55 b08c6af1-5177-4d33-ba66-4b1c6b8b522a 2001-06-06 21:07:01 +01:00			`</p>`
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