PHP Unconference Europe 2015

Closure::bind

(PHP 5 >= 5.4.0)

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

Description

public static Closure Closure::bind ( Closure $closure , object $newthis [, mixed $newscope = "static" ] )

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

Parameters

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 associate 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.

Return Values

Returns a new Closure object or FALSE on failure

Examples

Example #1 Closure::bind() example

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

$bcl1 Closure::bind($cl1null'A');
$bcl2 Closure::bind($cl2, new A(), 'A');
echo 
$bcl1(), "\n";
echo 
$bcl2(), "\n";
?>

The above example will output something similar to:

1
2

See Also

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User Contributed Notes 2 notes

up
27
Vincius Krolow
1 year 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
0
jaaf64 at zoraldia dot com
4 days ago
To make the previous example easier to catch and test for a learner of the language:
<?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 (
'Method "'.$methodName.'" exists and returns: '.call_user_func_array($this->methods[$methodName], $args));
        }
        return(
'Method "' .$methodName.'": There is no method with this name to call');
    }
}
?>

<?php
require 'MetaTrait.php';

class
HackThursday {
    use
MetaTrait;
    private
$dayOfWeek = 'Thursday';
}

$test = new HackThursday();
$test->addMethod('when', function () {
    return
$this->dayOfWeek;
});
echo
$test->when();
echo
'<br/>'.$test->phony();
?>
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