Daniel Kolbo wrote: > Say you have two classes: human and male. Further, say male extends > human. Let's say you have a human object. Then later you want to make > that human object a male object. This seems to be a pretty reasonable > thing to request of our objects. I don't think any human can change gender without major surgery, but I don't know if you just chose your example badly or whether you really think objects should be able to mutate into other types of object without some kind of special treatment. > This type of thing would especially be > easy if objects of parent classes could be cast as an object of its > extended class. Where would the extra data come from to fill in any fields the base class does not have? Just think of a simple example with a Shape class, extended by a ColouredShape class which contains some data about the object's colour - if you have a Shape object it can't become a ColouredShape without some surgery because bits of the ColouredShape's anatomy are not present. -- Gary Please do NOT send me 'courtesy' replies off-list. PHP 5.2.12 (cli) (built: Jan 14 2010 14:54:11) 1.7.7(0.230/5/3) 2010-08-31 09:58 Cygwin -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php