[Cython] setup.py and cmdclass

[Stefan Behnel]

T J wrote:
> [Sorry for all the posts...but hopefully, it gives the devs a sense of
> the varied user backgrounds]
>
> I've figured out how to get my cython extensions to compile via
> distutils.  This site:
>
>     http://wiki.cython.org/WrappingCPlusPlus
>
> says that I can pass the cmdclass keyword to the Extension() object.
> However, when I do this, I get (for example):
>
>    error: unknown file type '.pyx' (from 'primes.pyx')
>
> Only if I move the cmdclass declaration to the setup() will it compile
> properly.  That is fine, but now I wonder how I can handle extensions
> if they are not Cython extensions.  That is, suppose I have:
>
> from Cython.Distutils import build_ext
> setup(....
>           ext_modules=[Extension('primes', 'primes.pyx'),
> Extension('noncython', 'noncython.c')]
>           cmdclass={'build_ext': build_ext}
>          )
>
> Would this work?  My first reaction is that I don't want the cython
> build_ext for a non-cython extension.  Or is the Cython build_ext a
> superset of distutils.command.build_ext?

Apparently, you forgot to try it before posting. Reading the source would
also have answered your question.

Cython's own build_ext only special-cases .pyx files and passes on their
.c/.cpp result, so replacing it once and for all shouldn't hurt.

Stefan