[Python-Dev] clarification on PEP 3124 status

[Darren Dale]

Could somebody please clarify the status of PEP 3124? At
http://ftp.python.org/dev/peps/ , it is listed as "under
consideration", but http://ftp.python.org/dev/peps/pep-3124/ says it
has been deferred.

I was reading through the discussion on the python-3000 mailing list
archive, and at one point somebody asked for other examples where
generic functions are used in the community. The numpy project has a
basic generic function mechanism for numpy's ufuncs (regular functions
that operate on arrays), where subclasses of numpy.ndarray can define
__array_prepare__ (this method will be added in numpy-1.4) and
__array_wrap__ methods, which are sort of analogous to @before and
@after in PEP 3124 (ndarray subclasses define an __array_priority__
attribute to decide how to dispatch). The numpy approach is not a
general solution and is not as flexible as what is described in the
PEP, but it can be used by functions that operate on subclasses that
implement matrices, masked arrays, arrays with physical units.

I would be very interested in seeing a framework for generic functions
in the numpy standard library. I think would be more simple and
flexible than what we currently have. Is there still
interest/motivation for supporting generic functions in the standard
library?

Darren