[pypy-dev] What can Cython do for PyPy?

[Stefan Behnel]

Hi,

there has recently been a move towards a .NET/IronPython port of Cython, 
mostly driven by the need for a fast NumPy port. During the related 
discussion, the question came up how much it would take to let Cython also 
target other runtimes, including PyPy.

Given that PyPy already has a CPython C-API compatibility layer, I doubt 
that it would be hard to enable that. With my limited knowledge about the 
internals of that layer, I guess the question thus becomes: is there 
anything Cython could do to the C code it generates that would make the 
Cython generated extension modules run faster/better/safer on PyPy than 
they would currently? I never tried to make a Cython module actually run on 
PyPy (simply because I don't use PyPy), but I have my doubts that they'd 
run perfectly out of the box. While generally portable, I'm pretty sure the 
C code relies on some specific internals of CPython that PyPy can't easily 
(or efficiently) provide.

Stefan