George Sakkis <[EMAIL PROTECTED]> writes: > By the way, why do we need both NotImplementedError and the > NotImplemented singleton object ? Couldn't we have just one of them ?
One of them is an exception class, the other is not. They have rather different semantics. I think of NotImplemented as equivalent to None; it's useful as a sentinel value to set an attribute to in (e.g.) an abstract class. For a function that is (or has a flow branch which is) not (yet?) implemented, I don't want to return at all. Instead, I want to raise an instance of NotImplementedError. I think it's desirable to keep them both distinct as is. -- \ "If you get invited to your first orgy, don't just show up | `\ nude. That's a common mistake. You have to let nudity | _o__) 'happen.'" -- Jack Handey | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
