setting C++ mode in cythonize()

[Stefan Behnel]

Hi,

the documentation suggests to pass language='c++' into cythonize() to
globally enable C++ mode, but AFAICT, this never actually worked. Cython
previously ignored this option, Cython 0.21 rejects it, and we didn't
update the docs, so the current situation is outright confusing.

http://docs.cython.org/src/userguide/wrapping_CPlusPlus.html#specify-c-language-in-setup-py

To me, this option seems the one obvious way to do it, as it mimics the
distutils Extension API most closely. So, I now implemented support for
this, but only for modules found by file name, not for user provided
Extension objects. I think that's a reasonable restriction. If users
construct their own Extension instances anyway, they can just as well set
the 'language' option on them directly (and probably already do so).

https://github.com/cython/cython/commit/88df97f250073d8a06f965d6a7e09d8fe6f4ca63

Stefan

[Matthew Honnibal]

On Friday, 3 October 2014 17:27:54 UTC+10, Stefan Behnel wrote:

Hi,

the documentation suggests to pass language='c++' into cythonize() to
globally enable C++ mode, but AFAICT, this never actually worked. Cython
previously ignored this option, Cython 0.21 rejects it, and we didn't
update the docs, so the current situation is outright confusing.

http://docs.cython.org/src/userguide/wrapping_CPlusPlus.html#specify-c-language-in-setup-py

Thanks for this. Cython's a big project that's been changing fast, and as a user I've often found the docs a bit lacking.

For instance, I wanted to use language="c++" for pyximport, and had some trouble doing so. I found this answer on StackOverflow:

https://stackoverflow.com/questions/7620003/how-do-you-tell-pyximport-to-use-the-cython-cplus-option

It recommends the use of a "foo.pyxbld" file, in the same directory as "foo.pyx", which pyximport will read for options. I tried it, and it does indeed work. This blew me away --- I'm fairly sure it's never mentioned in the docs, and it left me with many questions...

My main question is: is this actually the recommended solution? Or is it there for historical reasons, e.g. via Pyrex?

[Björn Dahlgren]

For instance, I wanted to use language="c++" for pyximport, and had some trouble doing so. I found this answer on StackOverflow:

https://stackoverflow.com/questions/7620003/how-do-you-tell-pyximport-to-use-the-cython-cplus-option

It recommends the use of a "foo.pyxbld" file, in the same directory as "foo.pyx", which pyximport will read for options. I tried it, and it does indeed work. This blew me away --- I'm fairly sure it's never mentioned in the docs, and it left me with many questions...

My main question is: is this actually the recommended solution? Or is it there for historical reasons, e.g. via Pyrex?

 

I've never see nthat either. I think it would be great if pyximport looks for lines like:

 # distutils: language = c++

in the pyx file.

[Stefan Behnel]

Björn Dahlgren schrieb am 07.10.2014 um 12:58:
> I think it would be great if pyximport looks
> for lines like:
>
> # distutils: language = c++
>
> in the pyx file.

Pyximport only marginally changed since the old days of Pyrex. It should
use cythonize() for compilation.

We certainly take patches.

Stefan

[Robert Bradshaw]

On Tue, Oct 7, 2014 at 4:48 AM, Stefan Behnel <stef...@behnel.de> wrote:
> Björn Dahlgren schrieb am 07.10.2014 um 12:58:
>> I think it would be great if pyximport looks
>> for lines like:
>>
>> # distutils: language = c++
>>
>> in the pyx file.
>
> Pyximport only marginally changed since the old days of Pyrex. It should
> use cythonize() for compilation.

+1

> We certainly take patches.

Contribution to docs are also well accepted; often as developers we're
not in the best position to know what is and isn't obvious. You can
even edit them right online:

https://github.com/cython/cython/blob/master/docs/src/userguide/wrapping_CPlusPlus.rst

- Robert