Some times ago, I proposed an optional build for SWIG if the SWIG binary was not found on the system. Here I propose an enhancement, a new library builder that will be registered in the environment env as PythonModule. It takes the same arguments as a classical SharedLibrary, but it does some additional steps :
- It forces SWIG to create a Python wrapper (flag -python)
- It checks if SWIG is present at all
- It suppresses every prefix that the system might need (as lib in Linux)
- On Windows and for Python >= 2.5, it changes the extension as pyd
Here is the code :
import re
import sys
def SWIGSharedLibrary(env, library, sources, **args):
swigre = re.compile('(.*).i')
if env.WhereIs('swig') is None:
sourcesbis = []
for source in sources:
cName = swigre.sub(r'\1_wrap.c', source)
cppName = swigre.sub(r'\1_wrap.cc', source)
if os.path.exists(cName):
sourcesbis.append(cName)
elif os.path.exists(cppName):
sourcesbis.append(cppName)
else:sourcesbis.append(source)
else:sourcesbis = sourcesif 'SWIGFLAGS' in args:
args['SWIGFLAGS'] += ['-python']
else:args['SWIGFLAGS'] = ['-python'] + env['SWIGFLAGS']
args['SHLIBPREFIX']=""
if sys.version >= '2.5':
args['SHLIBSUFFIX']=".pyd"
cat=env.SharedLibrary(library, sourcesbis, **args)
return catenv['BUILDERS']['PythonModule'] = SWIGSharedLibrary
Once registered, a new SWIG module named mymodule can be created with :
env.PythonModule('_mymodule', ['myfile.i', 'myfile.c'])
I’m a bit confused at registering a python function directly as a Builder, instead of creating a custom Builder with an action or generator. I’d like to do something similar (so I can use other builders like you use env.SharedLibrary), but I’m not sure this is a supported usage… What exactly goes on here?
In fact, the real builder is still SharedLibrary for SCons. What I do is preprocess the sources in case SWIG is not available (I change .i for _wrap.c or _wrap.cc), and then I add ‘-python’ so that swig really understands it has to create a Python module. Finally, I change the library suffix and prefix if needed before I call the real builder, SharedLibrary.
When cleaning, doesn’t seem to remove the objects that build the _mymodule.pyd.
Thanks for the report, I’ll check this.
It’s surprising though, as the only thing I do is to decorate the SharedLibrary function.