Question

The problem is a need to take the arguments into account before choosing the responder. Here is my attempt so far.

from responders import A, B, C  class RandomResponder(object)     def init(self, *args, *kwargs):         self.args = args         self.kwargs = kwargs      def __getattr__(self, name):         # pick a responder based on the args the function was called with         # I don't know how to do this part         # for sake of argument lets the args a function was called with lead me to pick responder A         r = A         responder = r(*self.args, **self.kwargs)         return responder.__getattr__(name) 

The desired effect would be:

r = RandomResponder() r.doSomething(1) #returns A.doSomething() r.doSomething(2) #returns B.doSomething() r.doSomething(3) #return C.doSomething() r.doSomethingElse(1) #returns A.doSomethingElse() r.doSomethingElse(2) #returns B.doSomethingElse() r.doSomethingElse(3) #returns C.doSomethingElse() 

I will not know ahead of time all the functions contained with the responders A, B, and C.

Answer 1

Try this:

class RandomResponder(object):     choices = [A, B, C]      @classmethod     def which(cls):         return random.choice(cls.choices)      def __getattr__(self, attr):         return getattr(self.which(), attr) 

which() randomly selects an option from the choices, and which getattr uses to get the attribute.

EDIT: it actually looks like you want something more like this.

class RandomResponder(object):     choices = [A, B, C]      def __getattr__(self, attr):         # we define a function that actually gets called         # which takes up the first positional argument,         # the rest are left to args and kwargs         def doCall(which, *args, **kwargs):             # get the attribute of the appropriate one, call with passed args             return getattr(self.choices[which], attr)(*args, **kwargs)         return doCall 

This could be written using lambda, but I’ll just leave it like this so it’s clearer.