total idiot question: +=, .=, etc...

Guido van Rossum guido at cnri.reston.va.us
Tue Jun 29 13:27:05 CEST 1999


Greg Ewing <greg.ewing at compaq.com> writes:

> >     class A(B):
> >         def __init__(self, x, y, z):
> >             B.__init__(self, x, y, z)
> 
> I could live with having to explicitly name the
> superclass, provided something checked that the
> class I named was actually a direct base class
> of the one where the method is defined. That
> way things would be less likely to break
> mysteriously when I rearrange the class
> hierarchy.

Oh, but that check *is* being made!  (In fact this is the same check
that prevents "class methods" from working ;-)

>>> class A:
	def __init__(self):
		self.a = 1


>>> class B:
	def __init__(self):
		self.b = 1


>>> class C(B):
	def __init__(self):
		A.__init__(self)


>>> C()
Traceback (innermost last):
  File "<pyshell#12>", line 1, in ?
    C()
  File "<pyshell#11>", line 3, in __init__
    A.__init__(self)
TypeError: unbound method must be called with class instance 1st argument
>>> 

--Guido van Rossum (home page: http://www.python.org/~guido/)




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