Minimal example for boost::python in ros

This is a minimal ros package that uses boost::python to make a C++
function available to a python script.
There are some static paths that should better be handled by cmake,
though.

Author: Zandru

CMakeLists.txt

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+cmake_minimum_required(VERSION 2.8.3)
+project(boostpy_test)
+
+## Find catkin macros and libraries
+## if COMPONENTS list like find_package(catkin REQUIRED COMPONENTS xyz)
+## is used, also find other catkin packages
+find_package(catkin REQUIRED COMPONENTS
+  roscpp
+  rospy
+)
+
+## System dependencies are found with CMake's conventions
+find_package(Boost REQUIRED COMPONENTS python)
+
+
+## Uncomment this if the package has a setup.py. This macro ensures
+## modules and global scripts declared therein get installed
+## See http://ros.org/doc/api/catkin/html/user_guide/setup_dot_py.html
+# catkin_python_setup()
+
+
+
+###################################
+## catkin specific configuration ##
+###################################
+## The catkin_package macro generates cmake config files for your package
+## Declare things to be passed to dependent projects
+## INCLUDE_DIRS: uncomment this if you package contains header files
+## LIBRARIES: libraries you create in this project that dependent projects also need
+## CATKIN_DEPENDS: catkin_packages dependent projects also need
+## DEPENDS: system dependencies of this project that dependent projects also need
+catkin_package(
+#  INCLUDE_DIRS include
+#  LIBRARIES boostpy_test
+#  CATKIN_DEPENDS roscpp rospy
+#  DEPENDS system_lib
+)
+
+###########
+## Build ##
+###########
+
+## Specify additional locations of header files
+## Your package locations should be listed before other locations
+# include_directories(include)
+include_directories(
+  ${catkin_INCLUDE_DIRS}
+  ${Boost_INCLUDE_DIRS}
+  "/usr/include/python2.7" #TODO: let cmake find the path
+)
+
+add_library(mycpplib SHARED
+  src/mycpplib.cpp
+)
+
+target_link_libraries(mycpplib
+  ${catkin_LIBRARIES}
+  ${Boost_LIBRARIES}
+)

README.md

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+Using Boost::Python with cmake
+==============================
+
+The official boost documentation uses boosts own build tool `bjam`. To integrate it into a catkin build, I have to use
+cmake, though.
+This page looks like a very nice and detailed tutorial: https://www.preney.ca/paul/archives/107
+
+Maybe even better:
+https://github.com/ethz-asl/Schweizer-Messer/wiki/Adding-boost::python-exports-to-your-ROS-package

package.xml

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+<?xml version="1.0"?>
+<package>
+  <name>boostpy_test</name>
+  <version>0.0.0</version>
+  <description>The boostpy_test package</description>
+
+  <!-- One maintainer tag required, multiple allowed, one person per tag --> 
+  <!-- Example:  -->
+  <!-- <maintainer email="jane.doe@example.com">Jane Doe</maintainer> -->
+  <maintainer email="felix@todo.todo">felix</maintainer>
+
+
+  <!-- One license tag required, multiple allowed, one license per tag -->
+  <!-- Commonly used license strings: -->
+  <!--   BSD, MIT, Boost Software License, GPLv2, GPLv3, LGPLv2.1, LGPLv3 -->
+  <license>TODO</license>
+
+
+  <!-- Url tags are optional, but mutiple are allowed, one per tag -->
+  <!-- Optional attribute type can be: website, bugtracker, or repository -->
+  <!-- Example: -->
+  <!-- <url type="website">http://wiki.ros.org/boostpy_test</url> -->
+
+
+  <!-- Author tags are optional, mutiple are allowed, one per tag -->
+  <!-- Authors do not have to be maintianers, but could be -->
+  <!-- Example: -->
+  <!-- <author email="jane.doe@example.com">Jane Doe</author> -->
+
+
+  <!-- The *_depend tags are used to specify dependencies -->
+  <!-- Dependencies can be catkin packages or system dependencies -->
+  <!-- Examples: -->
+  <!-- Use build_depend for packages you need at compile time: -->
+  <!--   <build_depend>message_generation</build_depend> -->
+  <!-- Use buildtool_depend for build tool packages: -->
+  <!--   <buildtool_depend>catkin</buildtool_depend> -->
+  <!-- Use run_depend for packages you need at runtime: -->
+  <!--   <run_depend>message_runtime</run_depend> -->
+  <!-- Use test_depend for packages you need only for testing: -->
+  <!--   <test_depend>gtest</test_depend> -->
+  <buildtool_depend>catkin</buildtool_depend>
+  <build_depend>roscpp</build_depend>
+  <build_depend>rospy</build_depend>
+  <run_depend>roscpp</run_depend>
+  <run_depend>rospy</run_depend>
+
+
+  <!-- The export tag contains other, unspecified, tags -->
+  <export>
+    <!-- You can specify that this package is a metapackage here: -->
+    <!-- <metapackage/> -->
+
+    <!-- Other tools can request additional information be placed here -->
+
+  </export>
+</package>

scripts/use_cpplib.py

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+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+import rospy
+
+import sys
+# TODO: this is ugly... can this be set using cmake?
+sys.path.append("/home/felix/ws/ros/devel/lib")
+
+import libmycpplib as cpp
+
+# this is the equivalent to `main()` in c++
+if __name__ == '__main__':
+    rospy.init_node('use_cpplib')
+
+    cpp.hello()
+
+    #rospy.spin()

src/mycpplib.cpp

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+#include <iostream>
+#include <boost/python.hpp>
+
+using namespace std;
+
+void hello()
+{
+    cout << "Hello Python. I'm C++, looking forward to work with you!" << endl;
+}
+
+
+
+BOOST_PYTHON_MODULE(libmycpplib) // name has to match with the name in CMakeLists `add_library` + prefix 'lib'
+{
+   using namespace boost::python;
+   def("hello", hello);
+}