[Python-Dev] Requesting that a class be a new-style class

[Phillip J. Eby]

At 09:15 AM 2/20/05 +0100, Alex Martelli wrote:
>This is because types.ClassType turns somersaults to enable this: in this 
>latter construct, Python's mechanisms determine ClassType as the metaclass 
>(it's the metaclass of the first base class), but then ClassType in turn 
>sniffs around for another metaclass to delegate to, among the supplied 
>bases, and having found one washes its hands of the whole business;-).

To be pedantic, the actual algorithm in 2.2+ has nothing to do with the 
first base class; that's the pre-2.2 algorithm.  The 2.2 algorithm looks 
for the most-derived metaclass of the base classes, and simply ignores 
classic bases altogether.