callsuper.py

class CallSuper(Exception): pass


def callsuper(method):
    """
    Decorator for calling the super method automagically.
    
    In the submethod, if a ``CallSuper`` exception is raised at any point, then
    the wrapper will look up the class's MRO (method resolution order) for a
    method of the same name. If none is found, the exception is allowed to
    permeate. If one is found, it too is wrapped with the ``callsuper``
    decorator and called with the arguments passed to ``CallSuper.__init__()``.
    """
    def callsuper_wrapper(self, *args):
        try:
            return method(self, *args)
        except CallSuper, exc:
            supermethod, name = None, method.__name__
            for base in self.__class__.mro()[1:]:
                if (hasattr(base, name) and
                    hasattr(getattr(base, name), '__call__')):
                    supermethod = callsuper(getattr(base, name))
                    break
            if not supermethod:
                raise
            return supermethod(self, *exc.args)
    callsuper_wrapper.__name__ = method.__name__
    callsuper_wrapper.__doc__ = method.__doc__
    return callsuper_wrapper

# Test it out

global COUNTER
COUNTER = 0

class SuperClass(object):
    
    def method(self):
        global COUNTER
        COUNTER += 1 # Increment counter.

class SubClass(SuperClass):
    
    @callsuper
    def method(self):
        global COUNTER
        COUNTER += 1 # Increment counter.
        raise CallSuper

SubClass().method()
assert COUNTER == 2