Half-done features in PHP, pt 1

foo.php

<?php
$app->foo = function() { echo 'test'; die;};

$app->foo(); // ERROR

$f = $app->foo;

$f(); // SUCCESS


/*********************************************************
 Here's a modification to __call that would let you call
 dynamically assigned methods in the normal fashion. This
 is of limited uselfulness in PHP 5.3 because you can't
 reference $this
**********************************************************/

<?php

class Foo
{

	public function baz($txt) {
		echo "BAZ: $txt\n";
	}


	public function __call($name, $arguments) {

		if (isset($this->{$name}) && $this->{$name} instanceof Closure) {

			$m = $this->{$name};
			return call_user_func_array($m, $arguments);

		}

	}

}


$foo = new Foo();

$foo->bar = function($txt) { echo "BAR: $txt\n"; };

$foo->bar('This method was dynamically added');
$foo->baz('This method was defined in the class');



/*********************************************************
 Here's a version for PHP 5.4 that binds the scope at
 call time, letting us use $this within the Closure
**********************************************************/


trait Call_Dynamic_Methods {

	public function __call($name, $arguments) {

		if (isset($this->{$name}) && $this->{$name} instanceof Closure) {

			$this->{$name} = $this->{$name}->bindTo($this, $this);

			return call_user_func_array($this->{$name}, $arguments);

		}

		return parent::__call($name, $arguments);

	}
}


class Foo54
{
	use Call_Dynamic_Methods;

	public $thing = 'blazzoooo';

	public function baz($txt) {
		echo "BAZ: $txt\n";
	}

}


$foo = new Foo54();

$foo->baz('This method was defined in the class');

$foo->bar = function($txt) { echo "BAR: $txt\n"; };
$foo->bar('This method was dynamically added after instantiation');

$foo->bam = function($txt) { echo "BAM: $txt (" . $this->thing . ")\n"; };
$foo->bam('This method was dynamically added after instantiation, and references
	$this. It will be bound at __call time to set the scope');

$flar = 'poop';
$foo->bal = function($txt) use ($flar) { echo "BAL: $txt (" . $this->thing . ") ($flar)\n"; };
$flar = 'poop2';
$foo->bal('This will output "poop" and not "poop2"');

Just for thoroughness - here's the technical reason in a nutshell - remember that properties and methods can have the same names in PHP classes https://gist.github.com/1951282

Appreciate your insights into it, Elizabeth. Ultimately, I think functional languages are a Big Win, and it's always a bummer to come up against the limitations in PHP related to functional programming. Actually making it happen in the existing runtime is, I'm sure, very non-trivial.