> Nearly complete novice question: is there any (possible) overlap at all
> between DBC (which AFAIK has something to do with specifying method
> preconditions, postconditions, and invariants) and the sort of _optional_
> type declaration stuff that is proposed/planned for Python 3000 (that is
> supposed to help produce more efficient code and help detect errors earlier
> on)?
> 
> Conrad Schneiker
> (This note is unofficial and subject to improvement without notice.)

Well, no one really knows what python has in store, but I'd guess it would be
along the lines of dylan's optional type declarations which provide
documentation, error checking, and efficiency.  DBC is more like structured
assertions, which don't necessarily have anything to do with types.  There was
a discussion a while back about DBC on c.l.py, and some people posted some
hairy metaclass stuff.

Speaking of dylan, I wonder what matz's impression of it is?  Was there any
influence?  They seem strikingly similar in many ways, except dylan has a
slightly different OO model with multiple dispatch, and macros, and the
ability to compile down to c++-speed code.