[Python-3000] Abilities / Interfaces

[George Sakkis]

On 11/21/06, Guido van Rossum <guido at python.org> wrote:

> A. Preliminaries.
>
> There are some open issues that we should probably address before
> diving too deep into the specification of abilities or interfaces.
>
> 1. Abstract Base Classes (ABCs)?
>
> Are we sure that we have passed the station of ABCs, or should we
> revisit why those aren't sufficient for our purposes?
>
> Bill Janssen seems to be in favor of just using ABCs. Pro: less new
> infrastructure. Con: hard to add a new ABC on the fly to an existing
> 3rd party class (mucking with __bases__ is too much of a hack to
> seriously propose).
>
> I'd like to explore this some more before committing to anything.

I'd like that too, with some concrete examples if possible.  I'm still
unsure what interfaces buy us that ABCs (are these the same/equivalent
to mixins?) don't, especially with an adaptation/generic function
mechanism in place.

George