[Python-Dev] metaclass insanity (original) (raw)

Guido van Rossum guido@python.org
Tue, 05 Nov 2002 10:03:51 -0500

> Can someone provide a reason why you'd want to use nested classes? > I've never felt this need myself. What are the motivations?

XIST (http://www.livinglogic.de/Python/xist/) uses nested classes to map XML element types and their attributes to Python classes. For example the HTML element type img looks like this in XIST: class img(Element): class Attrs(Element.Attrs): class src(URLAttr): required = True class alt(TextAttr): required = True class align(TextAttr): values = ("top", "middle", ...)

That's cool.

--Guido van Rossum (home page: http://www.python.org/~guido/)