Overriding methods per-object

[Chris Rebert]

On Fri, Apr 17, 2009 at 6:22 PM, Pavel Panchekha <PavPanchekha at gmail.com> wrote:
> I've got an object which has a method, __nonzero__
> The problem is, that method is attached to that object not that class
>
>> a = GeneralTypeOfObject()
>> a.__nonzero__ = lambda: False
>> a.__nonzero__()
> False
>
> But:
>
>> bool(a)
> True

This is as documented. See
http://docs.python.org/3.0/reference/datamodel.html#special-lookup

>
> What to do?

Either wrap the object in another object of a class that does define
__bool__, or change GeneralTypeOfObject so it defines __bool__(),
possibly having its __bool__ delegate to another method, which you
could then override on a per-object basis similar to your current
code.

Cheers,
Chris
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