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<h2><code><a class="back" title="Return to index" href="../index.html#extends_protocol2_3">extends_protocol/2-3</a></code></h2>
<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>
extends_protocol(?protocol_identifier, ?protocol_identifier)
extends_protocol(?protocol_identifier, ?protocol_identifier, ?scope)
<h4>Errors</h4>
<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(scope, Scope)</code></dd>
</dl>
<h4>Examples</h4>
| ?- extends_protocol(listp, Protocol).
| ?- extends_protocol(Protocol, termp, private).
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Last updated on: October 21, 2001
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