[Python-Dev] Pickle implementation questions (original) (raw)

Bruce Christensen t-bruch at microsoft.com
Fri Jun 30 19:16:54 CEST 2006

Thanks for your responses, Martin!

Martin v. Löwis wrote:

Bruce Christensen wrote: > - Where are object.reduce and object.reduceex defined, and how > does copyreg.reduceex fit into the picture?

See http://docs.python.org/lib/node69.html

So just to be clear, is it something like this?

class object: def reduce(self): return copy_reg._reduce_ex(self, -1)

def __reduce_ex__(self, protocol):
    return copy_reg._reduce_ex(self, protocol)

Does _reduce_ex's behavior actually change depending on the specified protocol version? The only difference that I can see or think of is that an assert causes it to fail if the protocol is >= 2.

> - What does copyreg.constructor() do?

It does this: def constructor(object): if not callable(object): raise TypeError("constructors must be callable")

So it is part of the public interface? It's exported in all, but it appears that it's undocumented.

Thanks,

--Bruce

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