Stuff

<?php

class pre_testclass {
	function __construct($foo) {
		echo $foo. ' ';
	}
}

	function instantiateObj($class, $args) { 
		$args = array_values($args); 
		$code = 'new $class($args[' . implode('], $args[', array_keys($args)) . ']);'; 
		return eval($code); 
	}

$bar = 'testclass';
$foo = 'pre_'.$bar;
$$foo = instantiateObj($foo, array('hello'));

var_dump($pre_testclass);

// OUTPUT:
// hello NULL

?>