listinherited2.py

#!/usr/bin/env python3
# File listinherited.py (2.x + 3.x)


class ListInherited:
    """
    Use dir() to collection both instance attr and names inherited from
    its classes; Python 3.x shows more name than 2.x because of the
    implied object superclass in the new-style class model; getattr()
    fetches inherited names not in self.__dict__; user __str__, not
    __repr__, or else the loops when printing bound method!
    """

    def __attrname(self, indent=' '*4):
        result = 'Unders%s\n%s%%s\nOthers%s\n' % ('-'*77, indent, '-'*77)
        unders = []
        for attr in dir(self):  # instance dir
            if attr[:2] == '__' and attr[-2:] == '__':
                unders.append(attr)
            else:
                display = str(getattr(self, attr))[:82-(len(indent) + len(attr))]
                result += '%s%s=%s\n' % (indent, attr, display)
        return result % ', '.join(unders)

    def __str__(self):
        return '<Instance of %s, address %s:\n%s>' % (
            self.__class__.__name__,
            id(self),           # My address
            self.__attrname())  # name=value list


def tester(listerclass, sept=False):

    class Super:

        def __init__(self):
            self.data1 = 'spam'

        def ham(self):
            pass

    class Sub(Super, listerclass):

        def __init__(self):
            Super.__init__(self)
            self.data2 = 'eggs'
            self.data3 = 42

        def spam(self):
            pass

    instance = Sub()
    print(instance)
    if sept:
        print('-' * 80)


if __name__ == '__main__':

    tester(ListInherited)