scons-tool-swigpy

SCons tool to generate Python modules using Swig.

Installation

There are few ways to install this tool for your project.

From pypi

This method may be preferable if you build your project under a virtualenv. To add swigpy tool from pypi, type (within your wirtualenv):

pip install scons-tool-loader scons-tool-swigpy

or, if your project uses pipenv:

pipenv install --dev scons-tool-loader scons-tool-swigpy

Alternatively, you may add this to your Pipfile

[dev-packages]
scons-tool-loader = "*"
scons-tool-swigpy = "*"

The tool will be installed as a namespaced package sconstool.swigpy in project's virtual environment. You may further use scons-tool-loader to load the tool.

As a git submodule

1. Create new git repository:

   mkdir /tmp/prj && cd /tmp/prj
   touch README.rst
   git init

2. Add the scons-tool-swigpy as a submodule:

   git submodule add git://github.com/ptomulik/scons-tool-swigpy.git site_scons/site_tools/swigpy

3. For python 2.x create __init__.py in site_tools directory:

   touch site_scons/site_tools/__init__.py

   this will allow to directly import site_tools.swigpy (this may be required by other tools).

Usage example

Git-based projects

1. Create some source files, for example src/hello.hpp and src/hello.cpp:

   // src/hello.hpp
   #ifndef HELLO_HPP
   #define HELLO_HPP
   void hello();
   #endif

   // src/hello.cpp
   #include "hello.hpp"
   #include <iostream>
   void hello() { std::cout << "Hello" << std::endl; }

2. Create swig interface file src/hello.i

   // src/hello.i
   %module hello;
   %{
   #include "hello.hpp"
   %}
   %include "hello.hpp"

3. Write SConstruct file:

   # SConstruct
   env = Environment(tools = [ 'default', 'swigpy' ])
   SConscript('src/SConscript', exports=['env'], variant_dir='build', duplicate=0)

4. Write src/SConscript:

   # src/SConscript
   Import(['env'])
   env.Append( SWIGPY_CPPPATH = ['.'] )
   env.Append( SWIGPY_LIBPATH = ['.'] )
   env.Append( SWIGPY_SWIGFLAGS = ['-c++'] )
   env.SharedLibrary( 'hello', ['hello.cpp'] )
   env.SwigPyModule( 'hello', SWIGPY_LIBS = ['$SWIGPY_PYTHONLIB', 'hello'] )

5. Try it out:

   scons

   This shall create a library build/libhello.so and all the files that comprise its python wrapper:

   ptomulik@tea:$ ls build/
   hello.os  hello.pyc  hello_wrap.cc  libhello.so
   hello.py  _hello.so  hello_wrap.os

6. Test the generated wrapper:

   cd build
   LD_LIBRARY_PATH='.' python
   >>> import hello
   >>> hello.hello()

Details

Module description

The module provides a SwigPyModule() builder which generates python module based on a swig interface *.i file:

SwigPyModule(modname, **overrides)

The modname is a name of the module being generated, for example 'foo' or 'foo.bar' (note, it's neither the source file name nor target file name). The overrides overwrite construction variables such as SWIGFLAGS or CFLAGS.

Example 1:

The following code expects a foo.i interface file to be present and generates python module defined by this file.

SwigPyModule('foo')

Example 2:

The following code expects a foo/bar.i interface file to be present and generates python module defined by this file undef foo subdirectory.

SwigPyModule('foo.bar')

Construction variables

Construction variables used by SwigPyModule are summarized in the following table. Note that there are two groups of variables. The first group are the well known variables such as CFLAGS or SWIGFLAGS. The second group are the variables prefixed with SWIGPY_. These variables, if defined, overwrite the well known variables when generating python bindings.

Variable	Default
SWIG
SWIGVERSION
SWIGFLAGS
SWIGDIRECTORSUFFIX
SWIGCFILESUFFIX
SWIGCXXFILESUFFIX
SWIGPATH
SWIGINCPREFIX
SWIGINCSUFFIX
SWIGCOM
CPPPATH
SHLIBPREFIX
CCFLAGS
CFLAGS
CXXFLAGS
LIBS
LIBPATH
LDFLAGS
SWIGPY_SWIG
SWIGPY_SWIGVERSION
SWIGPY_SWIGFLAGS	[-python', '-builtin']
SWIGPY_SWIGDIRECTORSUFFIX
SWIGPY_SWIGCFILESUFFIX
SWIGPY_SWIGCXXFILESUFFIX
SWIGPY_SWIGPATH
SWIGPY_SWIGINCPREFIX
SWIGPY_SWIGINCSUFFIX
SWIGPY_SWIGCOM
SWIGPY_CPPPATH	["$SWIGPY_PYTHONINCDIR"]
SWIGPY_SHOBJPREFIX
SWIGPY_SHOBJSUFFIX
SWIGPY_SHLIBPREFIX	'_'
SWIGPY_SHLIBSUFFIX	.pyd on Windows
SWIGPY_LIBPREFIX	'_'
SWIGPY_LIBSUFFIX
SWIGPY_IMPLIBPREFIX	'_'
SWIGPY_IMPLIBSUFFIX
SWIGPY_WINDOWSEXPPREFIX	'_'
SWIGPY_WINDOWSEXPSUFFIX
SWIGPY_CC
SWIGPY_CXX
SWIGPY_SHCC
SWIGPY_SHCXX
SWIGPY_CCFLAGS
SWIGPY_CFLAGS
SWIGPY_CXXFLAGS
SWIGPY_SHCCFLAGS
SWIGPY_SHCFLAGS
SWIGPY_SHCXXFLAGS
SWIGPY_LIBS	["$SWIGPY_PYTHONLIB"]
SWIGPY_LIBPATH	["$SWIGPY_PYTHONLIBDIR"]
SWIGPY_LINKFLAGS
SWIGPY_M2SWIGFILE	lambda parts: path.join(*parts) + '.i'
SWIGPY_M2CFILE	lambda parts: path.join(*parts)
SWIGPY_M2SHLIBFILE	lambda parts: path.join(*parts)

The SWIGPY_M2SWIGFILE lambda determines the name of swig interface (source file). The SWIGPY_M2CFILE determines the name (without suffix) of the C or C++ wrapper file being generated by swig. The SWIGPY_M2SHLIBFILE determines the name of shared library that will contain the wrapper binary code after compilation (without prefix and suffix). The parts provided to any of these macros are the parts of modname, that is they're result of modname.split('.').

LICENSE

Copyright (c) 2014-2020 by Paweł Tomulik <ptomulik@meil.pw.edu.pl>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE