Re: C++ & Python

From: David Abrahams (abrahams_at_[hidden])
Date: 2000-10-16 10:58:57

Normally, people want to write the "business logic" of their applications in
Python and save C++ for the speed-critical components. If you can afford to
do what you're asking about, you might consider writing your whole
application in Python and dispensing with C++ altogether.  That said...

It isn't well-documented yet, but py_cpp can be used for this purpose. You
can use the py::Callback template to call methods on the objects you get
from Python, e.g. something like this should work:

// caveat: UNTESTED!
#include <py_cpp/pyptr.h>
#include <py_cpp/callback.h>
#include <py_cpp/py.h>
#include <Python.h>
int main()
{
   try {
       py::Ptr module(PyImport_ImportModule("weapons"));
       const int strength = 10;
       const char* manufacturer = "Vordon Empire";
       py::Ptr a_blaster(py::Callback<py::Ptr>::call_method(
                module.get(), "Blaster", strength, manufacturer));
       py::Callback<void>::call_method(a_blaster.get(), "Fire");
       int old_strength = py::Callback<int>::call_method(a_blaster.get(),
"get_strength");
       py::Callback<void>::call_method(a_blaster.get(), "set_strength", 5);
   }
   catch(...)
   {
   }
}

I think that CXX (http://cxx.sourceforge.net) may be better at this job than
py_cpp, though I'm not at all sure.

Good luck,
Dave
----- Original Message -----
From: "Ted Milker" <tmilker_at_[hidden]>

> I've been following the C++/python sig mailing list and saw your
> posts about py_cpp.  Reading the webpage, it exposes the C++
> classes you write to python, but can you recommend something for
> doing the opposite?  I'd like to write a lot of the high level
> objects(NPC AI, items/weapons/etc) in Python and allow C++ to use
> those objects.  That way I don't have to recompile the binary to
> modify the objects in the game world.
>
> Ted