[Python-Dev] PyPy 1.7 - widening the sweet spot (original) (raw)

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).

Cheers, Nick.

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

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