[Python-3000] Abilities / Interfaces

[Jonathan LaCour]

Phillip J. Eby wrote:

> In essence, interfaces turn libraries into "frameworks", but generic
> functions turn frameworks into libraries.  I didn't really discover
> this until January of last year, though, when I did some experiments
> in replacing various PEAK interfaces with generic functions.

This is easily the most important part of the conversation, IMO, and I
would hate for it to be missed. "Interfaces" in the Java universe are a
hard contract that everyone has to agree upon up-front, and if you don't
agree, you have to create your own framework that does the very same
things in a different way. What you end up with is a world of many
competing frameworks, none of which interoperate.

The alternative may not be as *familiar* but it certainly paints a much
brighter picture. If you have two different frameworks that take
slightly different approaches (or even _radically_ different approaches)
to the same problems, you can make them work together as one, rather
than having to pick one or the other. Its like framework detente!

Adopting Java-like interfaces just because they are "familiar" would be
a huge mistake, as it would condemn Python to the limitations of such an
implementation unnecessarily. This is Python 3000, not Java, and while I
certainly understand the argument of familiarity, I won't let something
that seems a tad magical at first scare me into a comfortable decision.

I have actually used generic functions (using RuleDispatch) in practice
and find them to not only be hugely powerful, but much more pragmatic.
Am I the only one out there who sees it this way?

--
Jonathan LaCour
http://cleverdevil.org