Decorator design: executing a method only if it has been overridden

I've stumbled in a tricky python question. Given (updated):

class A(object):
    def run(self):
        # This makes possible to determine if 'run' was overridden
        if self.run.im_func != A.run.im_func:
            print('Running in {0}'.format(self.__class__.__name__))

class B(A):
    def run(self):
        super(B, self).run()

class C(A):
    pass

b = B()
c = C() 
b.run()
>>> Running in B

c.run()
>>> # nothing :)

How would you design the @runoverriden decorator, that would do the job of conditional statement in A.run()?

Update: The purpose of this code is that A.run() should log the run() calls , only if it has been overridden.

Thank 开发者_Python百科you!

If I understand what you want:

import functools
def runoverridden(f):
    @functools.wraps(f)
    def wrapper(self, *args, **kw):
        if getattr(self, f.__name__).im_func != wrapper:
            return f(self, *args, **kw)
    return wrapper

class A(object):
    @runoverridden
    def run(self):
        print('Running in A')

class B(A):
    def run(self):
        super(B, self).run()
        print('Running in B')

class C(A):
    pass

b = B()
c = C() 
b.run()
c.run()

It sounds like you want ABCs. Specifically, the abstractmethod decorator.