<?xml version="1.0" encoding="utf-8"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"> <head> <meta http-equiv="content-type" content="application/xml+xhtml; charset=utf-8" /> <title>Logtalk built-in predicate: instantiates_class/2-3</title> <link rel="stylesheet" href="../../screen.css" type="text/css" media="screen"/> <link rel="stylesheet" href="../../print.css" type="text/css" media="print"/> </head> <body> <div class="top-left">Logtalk reference manual</div> <div class="top-right">Built-in predicate: instantiates_class/2-3</div> <div class="bottom-left"><span class="page"/></div> <div class="bottom-right"><span class="page"/></div> <div class="navtop"><a href="../../index.html">contents</a> > <a href="../index.html">reference manual</a> > <a href="../index.html#builtins">built-in predicates</a></div> <h2 class="codenp">instantiates_class/2-3<span id="builtins_instantiates_class2_3"/></h2> <h4>Description</h4> <pre>instantiates_class(Instance, Class) instantiates_class(Instance, Class, Scope)</pre> <p> Enumerates, by backtracking, all pairs of objects such that the first one instantiates the second. The relation scope is represented by the atoms <code>public</code>, <code>protected</code>, and <code>private</code>. </p> <h4>Template and modes</h4> <pre>instantiates_class(?object_identifier, ?object_identifier) instantiates_class(?object_identifier, ?object_identifier, ?scope)</pre> <h4>Errors</h4> <dl> <dt>Instance is neither a variable nor a valid object identifier:</dt> <dd><code>type_error(object_identifier, Instance)</code></dd> <dt>Class is neither a variable nor a valid object identifier:</dt> <dd><code>type_error(object_identifier, Class)</code></dd> <dt>Scope is neither a variable nor a valid entity scope:</dt> <dd><code>type_error(scope, Scope)</code></dd> </dl> <h4>Examples</h4> <pre>| ?- instantiates_class(water_jug, state_space). | ?- instantiates_class(Space, state_space, public).</pre> <div class="footer"> <div class="copyright"> <span>Copyright © <a href="mailto:pmoura@logtalk.org">Paulo Moura</a> — <a href="http://logtalk.org">Logtalk.org</a></span><br/> <span>Last updated on: October 26, 2006</span> </div> <div class="navbottom"> <span><a href="imports_category2_3.html">previous</a> | <a href="../../glossary.html">glossary</a> | <a href="specializes_class2_3.html">next</a></span><br/> <span><a href="http://validator.w3.org/check/referer">XHTML</a> + <a href="http://jigsaw.w3.org/css-validator/check/referer">CSS</a></span> </div> </div> </body> </html>