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<title>Logtalk control construct: ::/1</title>
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<div class="top-left">Logtalk reference manual</div>
<div class="top-right">Control construct: ::/1</div>
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<h2 class="codenp">::/1<span id="control_to_self1"/></h2>
<h4>Description</h4>
<pre>::Predicate
::(Predicate1, Predicate2, ...)
::(Predicate1; Predicate2; ...)</pre>
<p>
Send a message to <a class="glossary" title="Go to glossary definition" href="../../glossary.html#self">self</a>. Only used in the body of a predicate definition. The argument should match a public or protected predicate of <a class="glossary" title="Go to glossary definition" href="../../glossary.html#self">self</a>. It may also match a private predicate if the predicate is within the scope of the object where the method making the call is defined, if imported from a category, if used from inside a category, or when using private inheritance. We can also send a set of messages to self. The "<code>,</code>" and "<code>;</code>" in the list have the usual Prolog meaning.
</p>
<h4>Template and modes</h4>
<pre>::+messages</pre>
<h4>Errors</h4>
<dl>
<dt>Predicate is a variable:</dt>
<dd><code>instantiation_error</code></dd>
<dt>Predicate is declared private:</dt>
<dd><code>permission_error(access, private_predicate, Predicate)</code></dd>
<dt>Predicate is not declared:</dt>
<dd><code>existence_error(predicate_declaration, Predicate)</code></dd>
</dl>
<h4>Examples</h4>
<pre>area(Area) :-
::width(Width),
::height(Height),
Area is Width*Height.</pre>
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<span>Last updated on: October 26, 2006</span>
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