<!doctype html public "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <title>extends_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#extends_protocol2_3">extends_protocol/2-3</a></code></h2> <hr /> <h4>Description</h4> <blockquote> <pre> extends_protocol(Protocol1, Protocol2) extends_protocol(Protocol1, Protocol2, Scope) </pre> <p> Enumerates, by backtracking, all pairs of protocols such that the first one extends the second. </p> </blockquote> <h4>Template and modes</h4> <blockquote> <pre> extends_protocol(?protocol_identifier, ?protocol_identifier) extends_protocol(?protocol_identifier, ?protocol_identifier, ?entity_scope) </pre> </blockquote> <h3>Errors</h3> <blockquote> <dl> <dt>Protocol1 is neither a variable nor a valid protocol identifier:</dt> <dd><code>type_error(protocol_identifier, Protocol1)</code></dd> <dt>Protocol2 is neither a variable nor a valid protocol identifier:</dt> <dd><code>type_error(protocol_identifier, Protocol2)</code></dd> <dt>Scope is neither a variable nor a valid entity scope:</dt> <dd><code>type_error(entity_scope, Scope)</code></dd> </dl> </blockquote> <h4>Examples</h4> <blockquote> <pre> | ?- extends_protocol(listp, Protocol). | ?- extends_protocol(Protocol, termp, private). </pre> </blockquote> <hr /> <p class="center"> <strong><a href="extends_object2_3.html">Previous</a> | <a href="implements_protocol2_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: July 4, 2000 </p> <hr /> </body> </html>