Using metaclasses to inherit class variables
telesphore4 at gmail.com
telesphore4 at gmail.com
Mon May 22 17:27:56 EDT 2006
Sorry for not being clear.
Fresh copies of class vars so the first one is the correct: ('foo',
'bar', [], False)
>>> import copy
>>>
>>> class ClassVars(type):
... def __init__(cls, name, bases, dict):
... for name, value in type(cls).classVars.iteritems():
... if name not in dict:
... setattr(cls, name, copy.copy(value))
...
>>> def are(**kwargs):
... return type('', (ClassVars,), {'classVars':kwargs})
...
>>> class C(object):
... __metaclass__ = are(name='foo', desc='bar', list=[])
... name = 'not foo' #<<< Changing a copy only owned by this class
...
>>> class D(C):
... pass
...
>>> C.name, C.desc, C.list
('not foo', 'bar', []) <<<<<<<<<<<<<<<<<<<<<< Separate copy we changed
>>> D.name, D.desc, D.list, D.list is C.list
('foo', 'bar', [], False) <<<<<<<<<<<<<<<<<<<< Defaults are not changed
Both prints are correct here
Thanks for your help btw.
t4
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