[openbabel-scripting] Re: Python installation

[Geoffrey H. <ge...@ge...>]

>> BTW, do you think you could add a test to setup.py? I've included
>> some of my initial code below, but it's not bullet-proof yet.
>> Basically, I'd want setup.py to check "pkg-config --variable=prefix
>> openbabel-2.0" (best case) then /usr/local, then /usr, and
>> finally ../../src for libraries and include files. This should cover
>> the two obvious cases of an independent pyopenbabel.tar.gz and
>> something in the source/build directory.
>
> What do other packages do? I am not used to writing C extensions using
> distutils. Surely distutils checks 'the usual locations' for the
> library. One problem with providing several different mechanisms is  
> that
> you multiply the numbers of bugs and make them more difficult to track
> down. Personally, I would just find out the best way of doing this,  
> and
> force everybody to do it. How about the usual locations followed by  
> the
> location pointed to by the environment variable OpenBabelLib or
> something?

I haven't written many C/C++ extensions using distutils either -- it  
does not seem to be as easy to do as Perl, which has many C/C++ modules.

Distutils doesn't seem to be able to find "the usual locations" for  
libraries. Plus the python module probably has two distribution  
channels right now: as part of openbabel-2.x and hopefully as a  
separate download.

I imagine that the scripting wrappers will need releases more  
frequently than the main library.

> I don't like writing code like shown below as it's really  
> unportable. It
> should run on windows as easily (!) as on Linux/MacOSX. This is a bit
> hacky.
>
> import os
> if os.path.isfile(os.path.join("usr","local","lib","libopenbabel.a"):
> 	X
> else:
> 	y

OK, but Windows isn't going to have libraries in \usr\local\lib. I  
don't know about Cygwin.

Basically, I don't care much about syntax -- it seems like we want a  
bunch of checks:
- Run pkg-config (if it exists)
- Check /usr/local and /usr for libopenbabel.a
- Check ../../src/ if we might be in the build for libopenbabel.

I guess the main problem is that none of us know much about writing a  
setup.py script with Distutils for libraries. I've done Google  
searches but haven't turned up much. Any pointers?

Thanks,
-Geoff