En Thu, 24 Sep 2009 12:14:39 -0300, brian huggins <bgh...@aol.com>
escribió:
I want to set up descriptors at runtine, but it isn't working the way
i would expect. Does anybody know if this is possible?
class TestDesc (object):
x=Descriptor ("x")
def __init__ (self):
self.y=Descriptor("y")
test=TestDesc()
test.y
<descriptor.Descriptor object at 0x00B3A5F0>
When i access y, it appears to be a regular object and not a
descriptor type object like x. Is there a way to make y work the same
as x but setting it up during object creation?
The descriptor "magic" only happens when the attribute is looked up on the
class; when it's found in the instance itself, nothing special happens.
You cannot attach descriptors to a specific instance, but you can alter
its class at runtime. Basically you have to create a new class (that
inherits from the "real" class and adds the desired descriptor) and set it
as the instance __class__ attribute.
(This was discussed some time ago, try searching the list archives. Uh, I
found this:
http://groups.google.com/group/comp.lang.python/t/bfc093464dd6ba9/
but you should be able to find other threads)
--
Gabriel Genellina
--
http://mail.python.org/mailman/listinfo/python-list
