ID:               45925
 Updated by:       [EMAIL PROTECTED]
 Reported By:      david at grudl dot com
-Status:           Open
+Status:           Wont fix
 Bug Type:         Feature/Change Request
 Operating System: -
 PHP Version:      5.3.0alpha1
 New Comment:

__invoke takes arbitrary arguments, which means you can't have an
interface that covers it.


Previous Comments:
------------------------------------------------------------------------

[2008-08-26 16:33:13] david at grudl dot com

Description:
------------
It should be useful to encapsulate PHP pseudotype callback using new
magic method __invoke(). But this type of "callable" objects are not
distinguishable by any interface or class name (compare it with
ArrayAccess or Countable interfaces).

// this is simple callback encapsulation
class Callback 
{
        private $callback;

        public function __construct($callback)
        {
                $this->callback = $callback;
        }

        public function __invoke()
        {
                $args = func_get_args();
                return call_user_func_array($this->callback, $args);
        }
}


// a Callback object:
$callback = new Callback(array('MyClass', 'anyMethod'));

// a Closure object:
$closure = function() { ... };


The problem: there is nothing common between Callback and Closure
object, what can be used (for example) as type hinting. 

First solution using interface:

interface Callable { 
    function __invoke()
}

class Callback implements Callable { ... }

function event(Callable $obj)
{
        $obj($sender, $param);
}

event($callback);
event($closure); // do not work

The class Closure is not Callable implementor thus it do not work.
Problematic is __invoke method's parameters too.

The other way:

class Callback extends Closure { ... } // do not work

function event(Closure $obj)
{
        $obj($sender, $param);
}

event($callback);
event($closure);

This is not possible, because Closure is final. Solution is make
Closure non-final.

The third way - create static factory to encapsulate PHP callback as
Closure:

function event(Closure $obj)
{
        $obj($sender, $param);
}

$callback = Closure::factory(array('MyClass', 'anyMethod'));
event($callback);
event($closure);

Maybe the most easy way.



------------------------------------------------------------------------


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