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<title>Logtalk control construct: ::/2</title>
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<div class="top-left">Logtalk reference manual</div>
<div class="top-right">Control construct: ::/2</div>
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<h2 class="code">::/2</h2>
<h4>Description</h4>
<pre>Object::Predicate
(Object1, Object2, ...)::Predicate
(Object1; Object2; ...)::Predicate
Object::(Predicate1, Predicate2, ...)
Object::(Predicate1; Predicate2; ...)</pre>
<p>
Sends a message to an object. The message argument must match a public predicate of the receiver object. We can also send the same message to a set of objects or a set of messages to the same object. The "<code>,</code>" and "<code>;</code>" in the list have the usual Prolog meaning.
</p>
<h4>Template and modes</h4>
<pre>+receivers::+messages</pre>
<h4>Errors</h4>
<blockquote>
<dl>
<dt>Either Object or 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 declared protected:</dt>
<dd><code>permission_error(access, protected_predicate, Predicate)</code></dd>
<dt>Predicate is not declared:</dt>
<dd><code>existence_error(predicate_declaration, Predicate)</code></dd>
<dt>Object does not exist:</dt>
<dd><code>existence_error(object, Object)</code></dd>
</dl>
</blockquote>
<h4>Examples</h4>
<pre>| ?- list::member(X, [1, 2, 3]).
X = 1 ;
X = 2 ;
X = 3
yes</pre>
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<span class="date">Last updated on: November 16, 2005</span>
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