Writing a wrapper - any tips?

Stefan Behnel stefan_ml at behnel.de
Fri Jul 13 11:49:23 CEST 2012


Martin P. Hellwig, 13.07.2012 09:39:
> On Friday, 13 July 2012 05:03:23 UTC+1, Temia Eszteri  wrote:
>> I'm going to be looking into writing a wrapper for the Allegro 5 game
>> development libraries, either with ctypes or Cython. They technically
>> have a basic 1:1 ctypes wrapper currently, but I wanted to make
>> something more pythonic, because it'd be next to impossible to deal
>> with the memory management cleanly in the script itself.
>>
>> Anything I should keep in mind? Any tips to pass on to a first-time
>> module writer, pitfalls to watch out for, etc.?
> <cut>
> I would split the wrapping in layers, the lowest layer is a one on one
> exposure of the library with your wrapper, I would rather avoid ctypes
> for performance reasons, however if performance is not a concern ctypes
> is excellent and broadly available.
> 
> The next layer is purely there to make the lower layer pythonic, i.e.
> apply namespaces, automatic handling of memory, PEP8 naming convetions,
> etc. etc. just what you would expect from a modern pure python module
> 
> The next layer, if you want to, contains tools that are often used in
> that concept, think in the line of design patterns.

And the good thing about Cython in this context is that even if performance
*is* a concern, you can move code around between all three layers freely in
order to adjust it to your performance requirements and even drop the
lowest layer entirely. In fact, my advice is to really skip that lowest
layer in a Cython wrapper, because if it's really just a 1:1 mapping, it's
going to end up with a lot of boring and redundant code and you won't gain
anything from it.

Stefan




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