[boost] Re: boost/python: how to: call memberfunctions of an existing c++ object from python?

From: Marco Borm (mb.ml.boost_at_[hidden])
Date: 2005-03-10 06:16:14

David Abrahams wrote:
> Marco Borm <mb.ml.boost_at_[hidden]> writes:
> 
> 
>>It is also possible to do the following in my c++ 
>>object-code: "ret = boost::python::call<int>(PyFunction.ptr(), this );"
> 
> 
> But not so elegant or safe as:
>     ret = boost::python::extract<int>( PyFunction( *this ) );
thats true :-)

>>But now my problem: boost copies the object and passes only that
>>copy to the function.  Is it and how is it possible to make the
>>object accessible to the function within the python-script?
> 
> 
>     ret = boost::python::extract<int>( PyFunction( boost::ref(*this) ) );
To clarify: "this" isn't an instance of an boost/python object.
The Instance is created somewhere else without boost/python.
Because this, the code you gave me crashs in wrapper_base.hpp on an 
"dynamic_cast<wrapper_base const volatile*>(x)"

An example for what I want:
class CppClass {
  public:
  void foo();
  void bar();
  ....
};

BOOST_PYTHON_MODULE(test)
{
     boost::python::class_<CppClass>("CppClass", boost::python::no_init)
         .def("bar", &CppClass::bar)
        ...
     ;
}

void CppClass::foo()
{
   ....
   // call "foohelper" in python-script
   ret = boost::python::extract<int>( PyFunction( boost::ref(*this) ) );
   ....
}

// python script
def foohelper(cppobj):
        cppobj.bar()
        return 1234;

main()
{
   CppClass* object = new CppClass;
   object->foo();
}

Thanks for help!
Marco Borm