LychnisA scratchpad for thoughts on my journey through life

Classes are fun!

class AbstractMethod (object):
    def __init__(self, func):
        self._function = func

    def __get__(self, obj, type):
        return self.AbstractMethodHelper(self._function, type)

    class AbstractMethodHelper (object):
        def __init__(self, func, cls):
            self._function = func
            self._class = cls

        def __call__(self, *args, **kwargs):
            raise TypeError('Abstract method `' + self._class.__name__ \
                            + '.' + self._function + '\' called')

class MyAbstractObject (object):
    foo = AbstractMethod('foo')

class MyObject (MyAbstractObject):
    def foo(self):
        print 'foo'

def main():
    a = MyObject()
    a.foo()
    b = MyAbstractObject()
    b.foo()

> python test.py
foo
Traceback (most recent call last):
  File "test.py", line 25, in ?
    main()
  File "test.py", line 22, in main
    b.foo()
  File "/home/ivo/p/python/abstract-classes/AbstractMethod.py", line 19, in __call__
    raise TypeError('Abstract method `' + self._class.__name__ \
TypeError: Abstract method `MyAbstractObject.foo' called

Tags: , code, programming, python by ivo
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