metaclasses

Benjamin musiccomposition at gmail.com
Tue Mar 4 05:01:33 CET 2008


On Mar 3, 7:12 pm, castiro... at gmail.com wrote:
> What are metaclasses?

Depends on whether you want to be confused or not. If you do, look at
this old but still head bursting essay: http://www.python.org/doc/essays/metaclasses/.

Basically, the metaclass of a (new-style) class is responsible for
creating the class. This means when Python sees
class Foo(object):
    __metaclass__ = FooMeta
class FooMeta(type):
    def __new__(cls, name, bases, dct):
       #do something cool to the class
       pass
It asks FooMeta to create the class Foo. Metaclasses always extend
type because type is the default metaclass.



More information about the Python-list mailing list