[Python-Dev] PyPy 1.7 - widening the sweet spot

Nick Coghlan ncoghlan at gmail.com
Thu Nov 24 13:46:01 CET 2011

On Thu, Nov 24, 2011 at 10:20 PM, Maciej Fijalkowski <fijall at gmail.com> wrote:
> The problem is not with maintaining the modified directory. The
> problem was always things like changing interface between the C
> version and the Python version or introduction of new stuff that does
> not run on pypy because it relies on refcounting. I don't see how
> having a subrepo helps here.

Indeed, the main thing that can help on this front is to get more
modules to the same state as heapq, io, datetime (and perhaps a few
others that have slipped my mind) where the CPython repo actually
contains both C and Python implementations and the test suite
exercises both to make sure their interfaces remain suitably
consistent (even though, during normal operation, CPython users will
only ever hit the C accelerated version).

This not only helps other implementations (by keeping a Python version
of the module continuously up to date with any semantic changes), but
can help people that are porting CPython to new platforms: the C
extension modules are far more likely to break in that situation than
the pure Python equivalents, and a relatively slow fallback is often
going to be better than no fallback at all. (Note that ctypes based
pure Python modules *aren't* particularly useful for this purpose,
though - due to the libffi dependency, ctypes is one of the extension
modules most likely to break when porting).


Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia

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