Suppose I have the following structure:
class CasinoGame
self.expected_return
class CardGame(CasinoGame)
self.deck
def shuffle()
def reset() # get a new deck and shuffle
class Slot(CasinoGame)
self.credits
def spin()
def reset() # return credit to user, reset bonus progression
Now I want to introduce another class VideoPoker which is a card-based slot game. Ideally I want to use methods and variables from both CardGame and Slot classes. However, I'm hesitant to use the following structure (recombining tree?):
class VidPoker(CardGame, Slot)
I think it will be confusing to keep track of MRO and inheritance structure especially when I need to add more classes later, extending depth and width.
Ideally I want VidPoker to inherit Slot (video poker is technically a slot machine), but "borrow" functions from CardGame.
Is there any best practice, preferred way of structuring classes in these types of situation?
EDIT
A few folks suggested: Is it possible to do partial inheritance with Python?
I think mixin method (accepted answer) would be a good solution most of the time, but it will fail in certain cases where method uses class variable.
Example
# this works
class Class2(object):
def method(self):
print ("I am method at %s" % self.__class__)
class Class1(object): pass
class Class0(Class1):
method = Class2.method
ob = Class0()
ob.method()
# this doesn't work
class Class2(object):
s = 'hi'
def method(self):
print (self.s)
class Class1(object): pass
class Class0(Class1):
method = Class2.method
ob = Class0()
ob.method()
Back to my example, suppose CardGame has an immutable class variable num_decks used by shuffle method. I wouldn't be able to call shuffle from VidPoker if it inherits Slot.
