On 05/11/14 06:15, Roberto Martínez wrote:
The thing with this is tricky. I need the change in the instance,
> not in the class, because I have multiple instances and all of
> them must have different implementations of __call__.
Why not just use functions with closure if that's what you need?
def a(one):
two = 'three'
def mycall(self):
nonlocal two
print 'NEW'
return mycall
Python functions are objects.
The workaround of calling a different method inside __call__
> is not valid for my case because I want to change the *signature*
> of the function also -for introspection reasons.
This seems like they should be two totally separate classes. If the
signature is different, then it violates the substitution principle. If
it violates substitution, then there is no reason why they should be of
the same class.
This was my first approach, but it is not very informative to the user
and I prefer to have arguments with descriptive names. We have to change
__doc__ too, so this is not an ideal solution for me.
I tried to implement __getattribute__, but is not called either. :(
Or you can use an factory function:
def A(p):
def xcall(self):
return 'X'
def ycall(self):
return 'Y'
class _A(object):
__call__ = xcall if p == 'x' else ycall
return _A
>>> A('x')()(), A('y')()()
('X', 'Y')
or plain and simply just use inheritance if you want to pass an
isinstance check:
class A(object):
def __call__(self):
print 'OLD'
class A1(A):
def __call__(self):
print 'NEW'
What exactly, are you trying to do?
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