# Simple Python program to demonstrate how Python handles multiple inheritance

# We have classes A, B, C, and D. B and C inherit from A.
# D inherits from B and C.

# Both B and C define a method foo() and the program reveals
# what Python does in this situation.

# The print statements also show that Python is able to handle the
# fact that A is referenced twice by the inheritance hierarchy and 
# only creates one instance of A that is reference by both B and C.

# You can run this program by typing "python multi.py".

# Try creating a similar program in another language that supports
# multiple inheritance and see if that langauge makes different
# choices than Python.

class A(object):

    def __init__(self):
        print("In A's __init__")
        self.w = 10

class B(A):
    def __init__(self):
        print("In B's __init__")
        super(B, self).__init__()
        self.x = 20

    def foo(self):
        print("B's foo")

class C(A):
    def __init__(self):
        print("In C's __init__")
        super(C, self).__init__()
        self.y = 30

    def foo(self):
        print("C's foo")

# Try uncommenting the next line and commenting the one below it
# to see how the order of listing the superclasses affects
# the method invocation of foo()

class D(B, C):
# class D(C, B):
    def __init__(self):
        print("In D's __init__")
        super(D, self).__init__()
        self.z = 40

d = D()

for i in ["w", "x", "y", "z"]:
    print("d.%s = %d" % (i, getattr(d, i)))

d.foo()