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Newsgroups: comp.lang.python
Date: Tue, 16 Oct 2012 04:46:17 -0700 (PDT)
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Subject: Re: Providing a Python wrapper to a C++ type.
From: Marco Nawijn <nawijn@gmail.com>
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On Tuesday, October 16, 2012 1:39:44 PM UTC+2, Stefan Behnel wrote:
> Marco Nawijn, 16.10.2012 12:17:
>=20
> > On Tuesday, October 16, 2012 10:11:52 AM UTC+2, aaron.l...@gmail.com wr=
ote:
>=20
> >> I have a C++ module where I have a defined, working type. How would I
>=20
> >> make a wrapper for this type to be able to be used in Python? I am
>=20
> >> familiar(-ish) with the C-API for functions but I can't see concretely=
 how
>=20
> >> one would include an interface to a type.
>=20
> >>
>=20
> >> Is it this? http://docs.python.org/release/2.7.3/extending/newtypes.ht=
ml
>=20
> >=20
>=20
> > There are a few ways of doing this. At least three come to my mind:
>=20
> > 1. Wrap the C++ type yourself by using handcrafted code implemented wit=
h the Python C API
>=20
> > 2. Use SWIG to wrap the C++ code and (semi) automatically create the wr=
apper (http://www.swig.org/)
>=20
> > 3. Use BOOST Python to wrap the C++ code (http://www.boost.org/doc/libs=
/1_51_0/libs/python/doc/index.html)
>=20
> >=20
>=20
> > I would highly discourage (1) unless you are very brave and curious. Of=
course it is a nice excercise, but if you want something to work quickly I =
would recommend to use either (2) or (3).
>=20
> >=20
>=20
> > I have used both SWIG and BOOST Python and either of them worked pretty=
 well for me. In the end I selected BOOST Python, because I was only intere=
sted in the Python wrapping (SWIG could generate many other wrappers as wel=
l).
>=20
>=20
>=20
> There's also Cython, which provides a very flexible way (unlike SWIG) of
>=20
> doing these things easily (unlike C++ with Boost).
>=20
>=20
>=20
> http://docs.cython.org/src/userguide/wrapping_CPlusPlus.html
>=20
>=20
>=20
> I agree with discouraging 1) in specific.
>=20
>=20
>=20
> Stefan

Hi Stefan,

I never worked with Cython (but I know it is very powerful and interesting)=
 but in my mind there are slight differences in usage scenario between e.g.=
 Boost Python and Cython. For me the idea of Cython is that your main code =
is in Python, but you want to improve the performance of specific parts of =
the code. In that case, Cython is the way to go. In case of Boost Python, t=
he scenario for me is that you have a main program/library in C++, but you =
want to be able use the functionality from Python.=20

Do you agree with this view?

Marco