[Distutils] Newbie building SWIG wrappers with distutils

[W.T. Bridgman]

Hello,

I searched the list archives and found some mention of getting SWIG 
v1.3 working with distutils but I couldn't find anything on the results 
of that effort.

I've got a set of python modules that I'm beginning to convert to C/C++ 
extensions and some C/C++ code I want to wrap for Python using SWIG 
v1.3.  I can get the extensions to build and work on their own (MacOS X 
10.2.4, MacPython 2.3b1) but I can't get a distutils module to build 
them.

My package directory looks something like this:

Lib/
Lib/moduleA.py
Lib/moduleB.py
Packages/
Packages/__init__.py
Packages/moduleC/
Packages/moduleC/moduleC.i
Packages/moduleC/Lib/__init__.py
Packages/moduleC/Include/moduleC.h
Packages/moduleC/Src/moduleC.c

where moduleA, moduleB are currently pure python but which may 
eventually converted to wrappers around C code and moduleC is being 
built as an extension.

Based on the docs and study of other setup.py scripts, my script looks 
something like:

extra_compile_args=["-Ddarwin"]
packages=["WTBlib"]
package_dir={'WTBlib':"Lib"}
include_dirs=[os.path.join('/usr','local','lib')]
ext_modules=[]

packages.append('WTBlib.moduleC')
package_dir['WTBlib.moduleC']=os.path.join('Packages','moduleC','Lib')
include_dirs.append(os.path.join('Packages','moduleC','Include'))
ext_modules.append(Extension('moduleC',
     [os.path.join('Packages','moduleC','Src','moduleC.c'),
     os.path.join('Packages','moduleC','moduleC.i')],
     extra_compile_args = extra_compile_args,
     include_dirs=include_dirs))

setup(name='WTBlib',version = "0.1",
     packages = packages,
     package_dir = package_dir,
     description = "",
     include_dirs = include_dirs,
     ext_package = "WTBlib",
     ext_modules = ext_modules)

Currently, it fails trying to build the SWIG wrapper.  So I built the 
wrappers manually (moduleC_wrap.c and moduleC.py and modified setup.py 
accordingly.

I expected it to build in site-packages something like:

WTBlib/
WTBlib/moduleA.py
WTBlib/moduleB.py
WTBlib/moduleC/
WTBlib/moduleC/_moduleC.so
WTBlib/moduleC/moduleC.py
WTBlib/moduleC/__init__.py

which I believe is what I want.  However, after having to modify things 
like #include paths in the wrapper file I can finally get it to build 
something like:

WTBlib/
WTBlib/__init__.py
WTBlib/moduleA.py
WTBlib/moduleB.py
WTBlib/moduleC.so
WTBlib/moduleC/
WTBlib/moduleC/moduleC.py
WTBlib/moduleC/__init__.py

which just doesn't work at all.  Pretends to import but no guts in the 
routines.

Part of my problem is clearly that I don't understand how each of the 
components entered into the setup.py gets transformed into a path for 
such things as file copy and compilation parameters.  Is there a better 
source of info on that?

What is the status of letting distutils build the wrapper files?

Also, just what is the __init__.py file for and is there ever a reason 
to put routines in it?

Thanks,
Tom