an class="pre">(&#64;)/1</span></code></a></li>
</ul>
</li>
<li class="toctree-l3"><a class="reference internal" href="external_calls.html">Calling external predicates</a></li>
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</ul>
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<li class="toctree-l2"><a class="reference internal" href="../directives/index.html">Directives</a></li>
<li class="toctree-l2"><a class="reference internal" href="../predicates/index.html">Built-in pr