Interfaces (Re: Perl is worse! (was: Python is Wierd!))

[Jim Fulton]

Corran Webster wrote:
> 
> In article <oogg5.2633$6E.681244 at ptah.visi.com>, ge at nowhere.none (Grant
> Edwards) wrote:
> 
> > In article <Pine.GSO.4.10.10007281010300.4194-100000 at sundial>, Moshe
> > Zadka wrote:
> > >On Fri, 28 Jul 2000, Grant Edwards wrote:
> > >
> > >> Is 'sequence mapping' for list() an tuple() defined the same as
> > >> for the 'for' statement: it has a get_item(i) method that
> > >> returns either a value or raises an exception?
> > >
> > >Actually, I think these two want an __len__ method too.
> >
> > At this point somebody is required to complain about the
> > vagueness of Python interfaces, and if there was some sort of
> > language facility for defining the interface for a "sequence"
> > then I wouldn't have had to ask that question.
> >
> > Since it's Friday, and the person assigned to the task of
> > complaining about interfaces is off today, I've filled in
> > temporarily.  But I'm goign golfing at noon, so if you want to
> > argue about it you'll have to make an appointment with the
> > regular staff on Monday.  Since I'm just filling in, all I'd be
> > able to provide is rote contridiction -- which we all know
> > isn't a real argument...
> 
> Here's a little something that I've been fiddling with in my spare time
> for the past little while.  It's an interface definition mechanism which
> uses metaclasses to allow a heirarchy of interfaces (somewhat like the
> exception heirarchy).  See the docstrings for details on how to use it.
> 
> Warning:  This uses metaclasses, so your head may explode if you try to
> follow what is going on here.
> 
> Corran
> 
(interesting interface implementation skipped)

Have you looked at:

http://www.zope.org/Members/jim/PythonInterfaces/Summary

This looks very similar to what you've put together.
We are beginning to apply this in Zope.

Jim

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