On 1/1/2011 6:55 PM, K. Richard Pixley wrote:
Can anyone explain to me why this doesn't work?
class Foo(object):
@property
@classmethod
def f(cls):
return 4
I mean, I think it seems to be syntactically clear what I'm trying to
accomplish. What am I missing?
First, because classmethod returns a classmethod instance, not a
function, so what gets passed to property is the classmethod descriptor,
not an actual callable.
Second, because a property descriptor just returns itself when accessed
on the class. It only works on instances.
To do what you want, I think you would need to write your own descriptor
class. Something like this:
class classproperty(object):
def __init__(self, getter):
self._getter = getter
def __get__(self, instance, owner):
return self._getter(owner)
class Foo(object):
@classproperty
def f(cls):
return 4
Modify as needed if you want to accomodate setters and deleters as well.
Cheers,
Ian
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