Hello,
I noticed that bultin types like list, set, dict, tuple don't seem to adhere to the convention of using super() in constructor to correctly allow diamond-shaped inheritance (through MRO). For instance:
class A(object):
... def __init__(self): ... print "A.__init__" ... super(A, self).__init__() ...
class B(A, list):
... def __init__(self): ... print "B.__init__" ... super(B, self).__init__() ...
B.__mro__
(<class '__main__.B'>, <class '__main__.A'>, <type 'list'>, <type 'object'>)
B()
B.__init__ A.__init__ []
class C(list, A):
... def __init__(self): ... print "C.__init__" ... super(C, self).__init__() ...
C.__mro__
(<class '__main__.C'>, <type 'list'>, <class '__main__.A'>, <type 'object'>)
C()
C.__init__ []
It seems weird to me that I have to swap the order of bases to get the expected behaviour. Is there a reason for this, or is it simply a bug that should be fixed?
The documentation explicitly states that only one of the built-in types can be used as a base class: they aren't desinged to be mixed with each other.
regards Steve -- Meet the Python developers and your c.l.py favorites March 23-25 Come to PyCon DC 2005 http://www.pycon.org/ Steve Holden http://www.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
