if <assignment>:

[Delaney, Timothy]

["implementation defined" vs "undefined"]

OK - I was being a bit facetious in the rant ... I do know what the formal
differences are.

The practical differences OTOH are none at all IMO - something that is
"implementation defined" may as well be "undefined" because for all intents
and purposes you can't use it. You can't even rely on it retaining its
behaviour across versions unless specifically stated that it will do so. If
you absolutely *must* use the behaviour, you have to resort to all kinds of
platform detection and various other things.

I make a strong recommendation to people I work with never to use anything
in any language which is not "well-defined". Just one of the reasons I like
Python - there are so few areas where behaviour is not "well-defined" - and
most of those cases are non-important (for example, whether or not two
references to equal integers reference the same object).

Tim Delaney