Neil Schemenauer wrote:
>
> I've run into a problem with ExtensionClass which I believe can
> only be fixed by modifying Python. I will try to explain.
>
> I have an ExtensionClass which defines __cmp__. Depending on the
> objects being compared, the __cmp__ method may never be called.
> This is due to code in object.c that looks like this:
>
> if (PyInstance_Check(v) || PyInstance_Check(w)) {
> try to use use __cmp__ method
> }
> else {
> try number coerce and fall back on type name comparison
> }
>
> Extension classes can never pass the PyInstance_Check predicate.
> I've searched for all occurances of PyInstance_Check in the 2.0
> source. In many places that PyInstance_Check occurs a more
> general "is this an instance-like type" check would seem to be
> more suitable.
>
> Here is my proposal:
(snip)
I think you got some good answers later in the thread.
I'll point out that a work around is to make your ExtensionClass
a numeric type. Numeric types have different comparison
semantics that allow you to get around this limitation.
I did this a few months back for acquisition wrappers.
Jim
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