Implementing GtkTreeModel

Ok, so I'm trying to create my own class implementing GtkTreeModel to make it much faster when dealing with thousands of rows. The problem I have is there is a method called "foreach" that makes PHP blow a gasket when I try to define it. class TestTreeModel implements GtkTreeModel { public function foreach($callback_func) { // do stuff } // all the other abstract methods are defined properly } This will return: Parse error: syntax error, unexpected T_FOREACH, expecting T_STRING in foo.php on line xx Any idea on how to get around this? Thanks! -Matt