python绑定c++程序

很多时候需要给c++程序提供一种使用上的灵活性，脚本语言在这里就变得很重要了。采用Boost.Python为c++程序加一层shell，比较简单、简洁，对原有的c++代码也没有侵入性。今天试了一下，感觉不错，可以把它集成在现在正在做的项目中。

我主要参照David Abrahams的"Building Hybrid Systems with Boost.Python"(http://www.boost-consulting.com/writing/bpl.html)一文，该文中对编译 过程说的较少，偶就略做补充，为新手节省点时间（偶也是python新手）。

为c++类加python shell过程基本上如下：
(1)为c++类编写一个Boost.Python wrapper
(2)编译成so
(3)可以在python中调用了

针对David Abrahams的例子，偶的源文件如下：

例1：hello world 函数
(1)hello.cpp

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-->#include <stdexcept>
char const* greet(unsigned x)
{
   static char const* const msgs[] = { "hello", "Boost.Python", "world!" };

   if (x > 2)
       throw std::range_error("greet: index out of range");

   return msgs[x];
}

(2)hello_wrap.cpp

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-->#include <boost/python.hpp>

using namespace boost::python;

char const* greet(unsigned x);

BOOST_PYTHON_MODULE(hello)
{
    def("greet", greet, "return one of 3 parts of a greeting");
}

(3)makefile

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-->PYTHON_INCLUDE_FLAGS = \
    -I/usr/include/python2.4

LIB_FLAGS = \
    -lboost_python

SOURCE = \
    hello.cpp hello_wrap.cpp

all:${SOURCE}
    g++ ${PYTHON_INCLUDE_FLAGS} ${SOURCE} ${LIB_FLAGS} -shared -o hello.so
clean:
    rm -f hello *.o *.out *.so

(4)hello.py

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-->import hello
for x in range(3):
    print hello.greet(x)

例2：hello world类
(1)hello_class.cpp

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-->#include <boost/python.hpp>
#include <iostream>
using namespace std;
using namespace boost::python;

class World
{
public:

    void set(std::string msg) { this->msg = msg; }
   
    void greet()
    {
        cout << this->msg << endl;
     }
    
    string msg;
};

BOOST_PYTHON_MODULE(hello)
{
    class_<World> w("World");
    w.def("greet", &World::greet);
    w.def("set", &World::set);
};

(2)makefile

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-->PYTHON_INCLUDE_FLAGS = \
    -I/usr/include/python2.4

LIB_FLAGS = \
    -lboost_python

SOURCE = \
    hello_class.cpp

all:${SOURCE}
    g++ ${PYTHON_INCLUDE_FLAGS} ${SOURCE} ${LIB_FLAGS} -shared -o hello.so
clean:
    rm -f hello *.o *.out *.so

(3)hello_class.py

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-->import hello
planet = hello.World()
planet.set('howdy')
planet.greet()

更复杂的调用见上面提到的David Abrahams的文章。