PHP Conference Nagoya 2025

    Closure::bind

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

    Closure::bind — Duplicates a closure with a specific bound object and class scope

    Опис

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

    This method is a static version of Closure::bindTo(). See the documentation of that method for more information.

    Параметри

    closure

    The anonymous functions to bind.

    newThis

    The object to which the given anonymous function should be bound, or null for the closure to be unbound.

    newScope

    The class scope to which the closure is to be associated, or 'static' to keep the current one. If an object is given, the type of the object will be used instead. This determines the visibility of protected and private methods of the bound object. It is not allowed to pass (an object of) an internal class as this parameter.

    Значення, що повертаються

    Returns a new Closure object, or null on failure.

    Приклади

    Приклад #1 Closure::bind() example

    <?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";
    ?>

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    User Contributed Notes 2 notes

    up
    91
    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
    5
    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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