Calling an overridden method, superclass an calls overridden method

Question

This code throws an exception, AttributeError, \"wtf!\", because A.foo() is calling B.foo1(), shouldn\'t it call A.foo1()? Ho

Answer 1

One can see what Python is doing here, but the manner of overriding is a bit extreme. Take the case when class A defines 100 attributes and class B inherits these and add 1 more attribute. We want to be able to have the __init__() for B call the __init__() for A and let B's code define only its single attribute. Similarly, if we define a reset() method in A to set all attributes to zero, then the corresponding reset() method for B should be able just to call the reset() method for A and then zero out the single B attribute instead of having to duplicate all of A's code. Python is making difficult what is supposed to be a major advantage of object-oriented programming; that is, the reuse of code. The best option here is avoid overriding of methods that we really want to reuse. If you want to get a sense of the complications with Python here, try this code:

class X(object):
    def __init__ ( self ):
        print "X"
        self.x = 'x'
        self.reset()
        print "back to X"
    def reset ( self ):
        print "reset X"
        self.xx = 'xx'

class Y(X):
    def __init__ ( self ):
        print "Y"
        super(Y,self).__init__()
        self.y = 'y'
        self.reset()
        print "back to Y"
    def reset ( self ):
        print "reset Y"
        super(Y,self).reset()
        print "back to reset Y"
        self.yy = 'yy'

aY = Y()

(To make this work properly, remove the self.reset() call in __init__() for class Y.)