[Python-3000] Traits/roles instead of ABCs

[Bill Janssen]

Greg Ewing writes:
> But I don't think there is any such definition, and
> the confusion arises because people lazily use the
> vague term "file-like" instead of spelling out what
> they really mean ("has a read() method", etc.)

Yes, I agree with this.  That's why
http://wiki.python.org/moin/AbstractBaseClasses?highlight=%28AbstractBaseClasses%29
splits the "file-like" interface into a number of composable pieces.

Bill