[Tutor] What is the metaclass for?

[Danny Yoo]

> > Can someone describe under what a metaclass is for and under
> > circumstances do we need to consider using them?
>
>
> My short answer would be that metaclasses are a mechanism for black
> magic -- or at least, very dark grey magic. ;) Odds are good that if
> what you read about metaclasses makes no sense, then you're not likely
> to need metaclasses for anything that you're doing -- it's a very
> advanced subject for advanced programmers. (Read this as -- I don't know
> just what to do with them either, so I'm sticking to what I can
> understand! ;) They're a fairly new addition to Python and I never felt
> limited by their absence. But they seem to make some people happy...)


Does anyone have the Python Cookbook (dead trees version) handy?  I'm
actually still in Santa Fe, and forgot to bring mine with me, but I
remember seeing a really awesome example of metaclasses in one of the
later chapters in the Python Cookbook.  I'll be back home tomorrow, so
I'll try to correctly quote the example when I return.

Concrete examples often make abstract concepts less difficult to perceive.
Someone had once asked if the idea of an "interface" could be handled in
Python.  Metaclasses allow us to extend Python's idea of a class to
include interfaces:

    http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/164901


Hope this helps!