SWIG + expy

[Stefan Behnel]

Yingjie Lan, 28.04.2010 05:53:
>> From: Stefan Behnel
>> Yingjie Lan, 27.04.2010 08:30:
>>> Is it possible to use SWIG to parse C/C++, and provide
>> an interface for
>>> me to generate some code? I thought it might be good
>> to have SWIG help
>>> generate expy files, then generate the python
>> extension via expy.
>>
>> There have been similar discussions on the Cython mailing
>> list (you might want to search the archives). The main theme
>> seems to be that clang provides a suitable parser, and
>> several people have used it to write up a code generator for
>> their specific needs (you might want to look at those).
>
> Thank you very much, I will take a look at this.
> BTW, is there a similar project going on for Cython?

Not from the side of the core developers. As I said, some users have grown 
their own tools, but nothing generally usable has been contributed so far.

Anyway, the use case isn't as important as one might think. The only reason 
why one would want to use an automated wrapper generator is because a huge 
API needs to get wrapped quickly (such as Qt or GTK, for example), and 
performance doesn't really matter (like for a GUI toolkit).

Most people want a wrapper that is fast, efficient and well usable from 
Python code. In most cases, one, two or all of these three requirements 
will prohibit the use of a wrapper generator like SWIG or Boost, so you'll 
eventually end up writing a wrapper manually anyway. For Cython, such a 
tool would mostly generate the .pxd declarations and potentially a one-time 
skeleton that users would then adapt to their needs, and that they would 
likely rewrite broadly. C APIs usually don't fit Python very well, and C++ 
APIs only do so in rare cases.

Even if the wrapped C/C++ API is big, it can often benefit from a smaller, 
more high-level wrapper, rather than transferring all low-level quirks into 
Python space and annoying users with them. A keyword argument here and 
there is much better than yet another function, and any manual memory 
management is straight out in the first place.

Stefan