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    Closure::bind

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

    Closure::bind — 用特定的绑定对象和类作用域复制闭包。

    说明

    public static Closure::bind(Closure $closure, ?object $newThis, object|string|null $newScope = "static"): ?Closure

    这个方法是 Closure::bindTo() 的静态版本。查看它的文档获取更多信息。

    参数

    closure

    需要绑定的匿名函数。

    newThis

    需要绑定到匿名函数的对象，或者 null 创建未绑定的闭包。

    newScope

    想要绑定给闭包的类作用域，或者 'static' 表示不改变。如果传入一个对象，则使用这个对象的类型名。 类作用域用来决定在闭包中 $this 对象的 私有、保护方法 的可见性。 不允许内置类（的对象）作为参数传递。

    返回值

    返回一个新的 Closure 对象，失败时返回 null。

    示例

    示例 #1 Closure::bind() 示例

    <?php
    class A {
    private static     $sfoo = 1;
    private     $ifoo = 2;
    }
    $cl1 = static function() {
    return     A::$sfoo;
    };
    $cl2 = function() {
    return     $this->ifoo;
    };

    $bcl1 = Closure::bind($cl1, null, 'A');
    $bcl2 = Closure::bind($cl2, new A(), 'A');
    echo     $bcl1(), "\n";
    echo     $bcl2(), "\n";
    ?>

    以上示例的输出类似于：

    1
2

    参见

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    User Contributed Notes 2 notes

    up
    88
    Vincius Krolow
    11 years ago
    With this class and method, it's possible to do nice things, like add methods on the fly to an object.

    MetaTrait.php
    <?php
    trait MetaTrait
    {
       
        private     $methods = array();

        public function     addMethod($methodName, $methodCallable)
        {
            if (!    is_callable($methodCallable)) {
                throw new     InvalidArgumentException('Second param must be callable');
            }
                $this->methods[$methodName] = Closure::bind($methodCallable, $this, get_class());
        }

        public function     __call($methodName, array $args)
        {
            if (isset(    $this->methods[$methodName])) {
                return     call_user_func_array($this->methods[$methodName], $args);
            }

            throw     RunTimeException('There is no method with the given name to call');
        }

    }
    ?>

    test.php
    <?php
    require 'MetaTrait.php';

    class     HackThursday {
        use     MetaTrait;

        private     $dayOfWeek = 'Thursday';

    }

    $test = new HackThursday();
    $test->addMethod('when', function () {
        return     $this->dayOfWeek;
    });

    echo     $test->when();

    ?>
    up
    4
    potherca at hotmail dot com
    9 years ago
    If you need to validate whether or not a closure can be bound to a PHP object, you will have to resort to using reflection.

    <?php

    /**
    * @param \Closure $callable
    *
    * @return bool
    */
    function isBindable(\Closure $callable)
    {
            $bindable = false;

            $reflectionFunction = new \ReflectionFunction($callable);
        if (
                $reflectionFunction->getClosureScopeClass() === null
                || $reflectionFunction->getClosureThis() !== null
            ) {
                $bindable = true;
        }

        return     $bindable;
    }
    ?>
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