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

匿名函数
Closure::bindTo() - 用特定的绑定对象和类作用域复制闭包。

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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();

?>

down

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;
}
?>