substitution of a method by a callable object
tjreedy at udel.edu
Wed Oct 22 22:34:44 CEST 2008
George Sakkis wrote:
> On Oct 22, 12:13 pm, netimen <neti... at gmail.com> wrote:
>> Can I substitute a method of a class by a callable object (not a
>> function)? I can very easy insert my function in a class as a method,
>> but an object - can't.
>> I have the following:
>> class Foo(object):
>> class Obj(object):
>> def __call__(self, obj_self):
>> print 'Obj'
>> def func(self):
>> print 'func'
>> f = Foo()
>> Foo.meth = func
>> f.meth() # all goes OK
>> Foo.meth = Obj()
>> f.meth() # I get TypeError: __call__() takes exactly 2 arguments (1
> You have to wrap it as an (unbound) instance method explicitly:
Nope. As the error message says, the method was called with nothing
provided to be bound to the extraneous parameter obj_self. Either
provide an arg, such as with f.meth(1), *or* delete obj_self and 'Obj'
is printed, with both 2.5 and 3.0.
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