ArrayAccess/ArrayObject return by reference

Looking at: http://lxr.php.net/xref/PHP_5_5/Zend/zend_interfaces.c#538 it seems that ArrayAccess at the moment can not be returned by a reference. I'm wondering if there was a technical reason behind this or if it is now a BC reason? Anyhow; I was attempting to dig through the source code a bit more last night to see why ArrayObject could not overload the function declaration of offsetGet to force a return by reference aka: function &offsetGet($key)... which works now for ArrayAccess but not for ArrayObject. I believe it has to deal with ArrayObject inheriting ArrayAccess? Is there a way to allow ArrayObject to change the function declaration in this way? My PHP internals skills are not the best which is the reason for the question. Anyhow; justification wise: in userland this leads to a lot of wtf factor. It really comes down to having to provide our own implementation of ArrayObject by extending several different areas including ArrayAccess so that references can be returned so multi-dimensional arrays can be properly unset aka: $ar = new ArrayObject(array('foo' => array('bar' => array('baz' => 'foo')))); unset($ar['foo']['bar']['baz']); Regards, Mike