Returns whether parameter MUST be callable

# ReflectionParameter::isCallable

(PHP 5 >= 5.4.0, PHP 7, PHP 8)

ReflectionParameter::isCallable — Returns whether parameter MUST be callable

警告

本函数已自 PHP 8.0.0 起被废弃。强烈建议不要依赖本函数。

See the example below for an alternative way to derive this information.

### 说明

#[\Deprecated]
public function ReflectionParameter::isCallable(): bool

警告

本函数还未编写文档，仅有参数列表。

### 参数

此函数没有参数。

### 返回值

Returns `true` if the parameter is callable, `false` if it is not or `null` on failure.

### 更新日志

版本 | 说明
--- | ---
8.0.0 | This function has been deprecated in favor of ReflectionParameter::getType() instead.

### 示例

示例 #1 PHP 8.0.0 equivalent

As of PHP 8.0.0, the following code will report if a type supports callables, including as part of a union.

    <?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));
    }
    ?>

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