Multiple inheritance on PHP

multiple-inheritance.php

<?php

class GranFather 
{
	function a()
	{
		return 'GranFather.A';
	}
	function b()
	{
		return 'GranFather.B';
	}
}

class Father
{
	private $parent, $extend = 'GranFather';
	function __parent()
	{
		if (!$this->parent) $this->parent = new $this->extend();
		return $this->parent;
	}
	function __call($foo, $args)
	{
		return call_user_func_array(array($this->__parent(), $foo), $args);
	}
	function __get($var)
	{
		return $this->__parent()->__get($var);
	}

	function a()
	{
		return 'Father.A - OVERRIDE';
	}
}

class Child
{
	private $parent, $extend = 'Father';
	function __parent()
	{
		if (!$this->parent) $this->parent = new $this->extend();
		return $this->parent;
	}
	function __call($foo, $args)
	{
		return call_user_func_array(array($this->__parent(), $foo), $args);
	}
	function __get($var)
	{
		return $this->__parent()->__get($var);
	}
	function a()
	{
		return 'Child.A - OVERRIDE AGAIN';
	}
}

$g = new GranFather();
$f = new Father();
$c = new Child();

echo "GranFather.A: ".$g->a()."\n";
echo "GranFather.B: ".$g->b()."\n";
echo "Father.A(): ".$f->a()."\n";
echo "Father.B(): ".$f->b()."\n";
echo "Child.A(): ".$c->a()."\n";
echo "Child.B(): ".$c->b()."\n";