[Python-Dev] Class decorators (original) (raw)

Guido van Rossum guido at python.org
Tue Mar 28 06:02:20 CEST 2006

On 3/27/06, Phillip J. Eby <pje at telecommunity.com> wrote:

PyProtocols and the zope.interface package both support inline class decorators called "class advisors". They don't require any special syntax, and aren't much more complex than regular decorators. By defining an advisor like this:

from protocols.advice import addClassAdvisor def someadvisor(whateverargs): def callback(cls): print "I can modify",cls,"or replace it" return cls addClassAdvisor(callback) you can then use it in a class body like so: class SomeClass: someadvisor("something") And the return value from 'callback' will replace SomeClass, just like a decorator replaces the function it's called on. The implementation should work with any Python version from 2.2 up. I'm not sure if it would work with IronPython. But if it doesn't, that would be a good indication of feature(s) that IronPython is missing. ;)

Just curious (and lazy): what magic is the implementation using that makes this work without a custom metaclass?

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

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