oo.php

<?php

// You should make this something that is sensible for your application
namespace gist;

/**
 * You can't set functions as callable properties on a normal generic
 * object. You can on instances of this class.
 *
 * You can't use "$this," however, so the function will always receive a
 * reference to "$this" as the first argument.
 *
 * It may not be the wisest thing to use the name StdClass here, but that's what I did.
 */
class StdClass
{
	/**
	 * This is just here as a convenience, since with a real class you lose
	 * the ability to instantiate via (object)array('key' => <value>)
	 */
	function __construct(array $properties=array())
	{
		foreach ($properties as $k => $v) 
		{
			$this->$k = $v;
		}
	}

	function __call($name, $args)
	{
		return call_user_func_array($this->$name, array_merge(array($this), $args));
	}
}

// Allow chaining method calls off the constructor..
function StdClass(array $properties=array())
{
	return new StdClass($properties);
}

// Define the 'class' class
$class = StdClass(array(
	'new' => function ($class) {
		return StdClass(array_merge((array)$class, array(
			'new' => function($class) {
				$obj = StdClass((array)$class);
				$args = func_get_args();
				array_shift($args);
				call_user_func_array(array($obj, 'init'), $args);
				return $obj;
			},
		)));
	},
	'def' => function ($t, $name, $fn) {
		$t->$name = $fn;
		return $t;
	},
	'extend' => function ($t) {
		return clone $t;
	}
));

// Define a new class
$animal = $class->new()
	->def('init', function($t, $name) {
		$t->name = $name;
	})
	->def('speak', function($t) {
		echo "My name is $t->name\n";
	});

// Extend a class
$dog = $animal->extend()
	->def('speak', function($t) {
		echo "My name is $t->name, I have just met you and I love you, SQUIRREL!\n";
	})
	->def('bark', function($t) {
		echo "Woof!\n";
	});

$jimmy = $animal->new('Jimmy');
$jimmy->speak();

$doug = $dog->new('Doug');
$doug->speak();
$doug->bark();

I really just set out to make a substitute for StdClass that you could attach callable methods too, but then I realized that this was basically the same thing that dhotson had done in his oo.php, so I merged the two. This one is simpler; it leaves out the fn() method as it's pure syntactic sugar, but here we include data members as well as just methods.