module with __call__ defined is not callable?

[limodou]

On 2/8/06, adam johnson <adam.sven.johnson at gmail.com> wrote:
> Thanks for you answer.
>
> I was under the impression that you could tack methods onto an object at any
> time, your example almost works with old style classes and would with a
> function instead of a method.
>
> >>> class A:
> ...     def __init__(self):
> ...             self.__call__ = A.hello
> ...     def hello(self):
> ...             print "Hello, world!"
> ...
> >>> a = A()
> >>> a()
> Traceback (most recent call last):
>   File "<stdin>", line 1, in ?
> TypeError: unbound method hello() must be called with A instance as first
> argument (got nothing instead)
> >>> a(a)
> Hello, world!
> >>>
>
> So now all I need to know is why now with new style classes the special
> functions need to be defined on the class instead of attached to the
> instance at any time.
>
don't need do like above!

 >>> class A:
 ...     def __init__(self):
 ...             A.__call__ = A.hello
 ...     def hello(self):
 ...             print "Hello, world!"

 >>> a = A()
 >>> a()
 Hello, world!

You should review the bound method and unbound method.

--
I like python!
My Blog: http://www.donews.net/limodou
NewEdit Maillist: http://groups.google.com/group/NewEdit