使用boost python传递函数引用

Question

我在C++中有这样一个函数：

typedef boost::function<boost::shared_ptr<Object> (CL_DomElement*, std::string& desc)> Parser;
void registerParser(std::string type, Parser p);

// Later: exporting into python-module:
BOOST_PYTHON_MODULE(TypesManager)
{
    bp::def("RegisterParser", registerParser);
}

# Python code:
class TestObj(Object):
    @staticmethod
    def ParseTestObj(node, desc):
        pass

RegisterParser("test_obj", TestObj.ParseTestObj)

python代码中的Object是在c++代码中使用的导出类。

Boost.Python.ArgumentError: Python argument types in
    RegisterParser(str, function)
did not match C++ signature:
    RegisterParser(TypesManager {lvalue}, std::string, boost::function<boost::shared_ptr<Object> ()(CL_DomElement*, std::string&)>)

我做错了什么？

Answer 1

我不相信Boost Python知道如何将python函数转换为boost::function对象。我建议使用代理来获取python callable对象并模拟C++接口。快速示例模型(当然是未经测试的)：

typedef boost::function<boost::shared_ptr<Object> (CL_DomElement*, std::string& desc)> Parser;
void registerParser(std::string type, Parser p);

struct ParserProxy
{
    bp::object callable;

    ParserProxy(bp::object callable)
    : callable(callable)
    { }

    boost::shared_ptr<Object> operator()(CL_DomElement* elem, std::string& desc)
    {
        bp::object obj = callable(elem, desc);
        return bp::extract<boost::shared_ptr<Object> >(obj);
    }
};

void registerParserByProxy(std::string type, bp::object callable)
{
    registerParser(type, ParserProxy(callable));
}

// Later: exporting into python-module:
BOOST_PYTHON_MODULE(TypesManager)
{
        bp::def("RegisterParser", registerParserByProxy);
}