<?xml version="1.0" encoding="utf-8"?>
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<refentry xml:id="reflectionparameter.iscallable" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
 <refnamediv>
  <refname>ReflectionParameter::isCallable</refname>
  <refpurpose>Returns whether parameter MUST be callable</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
   &warn.deprecated.function-8-0-0;
  <para>See the example below for an alternative way to derive this information.</para>
 </refsynopsisdiv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis role="ReflectionParameter">
   <modifier>public</modifier> <type>bool</type><methodname>ReflectionParameter::isCallable</methodname>
   <void/>
  </methodsynopsis>
  <para>

  </para>

  &warn.undocumented.func;

 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  &no.function.parameters;
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns &true; if the parameter is <type>callable</type>, &false; if it is
   not or &null; on failure.
  </para>
 </refsect1>

 <refsect1 role="examples">
 &reftitle.examples;
 <para>
  <example>
   <title>PHP 8.0.0 equivalent</title>
   <para>
    As of PHP 8.0.0, the following code will report if a type supports callables,
    including as part of a union.
   </para>
   <programlisting role="php">
<![CDATA[
<?php
function declaresCallable(ReflectionParameter $reflectionParameter): bool
{
    $reflectionType = $reflectionParameter->getType();

    if (!$reflectionType) return false;

    $types = $reflectionType instanceof ReflectionUnionType
        ? $reflectionType->getTypes()
        : [$reflectionType];

   return in_array('callable', array_map(fn(ReflectionNamedType $t) => $t->getName(), $types));
}
?>
]]>
   </programlisting>
  </example>
 </para>
 </refsect1>

</refentry>
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