<!doctype html public "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <title>implements_protocol/2-3</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#implements_protocol2_3">implements_protocol/2-3</a></code></h2> <hr /> <h4>Description</h4> <blockquote> <pre> implements_protocol(Object, Protocol) implements_protocol(Category, Protocol) implements_protocol(Object, Protocol, Scope) implements_protocol(Category, Protocol, Scope) </pre> <p> Enumerates, by backtracking, all pairs of entities such that an object or a category implements a protocol. </p> </blockquote> <h4>Template and modes</h4> <blockquote> <pre> implements_protocol(?object_identifier, ?protocol_identifier) implements_protocol(?category_identifier, ?protocol_identifier) implements_protocol(?object_identifier, ?protocol_identifier, ?scope) implements_protocol(?category_identifier, ?protocol_identifier, ?scope) </pre> </blockquote> <h4>Errors</h4> <blockquote> <dl> <dt>Object is neither a variable nor a valid object identifier:</dt> <dd><code>type_error(object_identifier, Object)</code></dd> <dt>Category is neither a variable nor a valid category identifier:</dt> <dd><code>type_error(category_identifier, Category)</code></dd> <dt>Protocol is neither a variable nor a valid protocol identifier:</dt> <dd><code>type_error(protocol_identifier, Protocol)</code></dd> <dt>Scope is neither a variable nor a valid entity scope:</dt> <dd><code>type_error(scope, Scope)</code></dd> </dl> </blockquote> <h4>Examples</h4> <blockquote> <pre> | ?- implements_protocol(List, listp). | ?- implements_protocol(List, listp, public). </pre> </blockquote> <hr /> <p class="center"> <strong><a href="extends_protocol2_3.html">Previous</a> | <a href="imports_category2_3.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: October 21, 2001 </p> <hr /> </body> </html>