[C++-sig] very basic: calling python function from c++

[Roel Vanhout]

Hello everybody, I'm only just starting out with boost.python and with 
python embedding and I have a very basic question. I have found examples 
of how to get an object into c++ from python and call functions on it, 
but what I'm trying to do is to get a function pointer to a python 
function and call that function with two parameters. Basically I have 
two numbers and users can enter an expression into the gui of the c++ 
program like this:

return num1 + num2

I thought that then in my c++ program, I'd prepend 'function 
calculate(num1, num2):' to that string, indent the expresson properly 
and then run the whole thing in python, passing the two numbers that I 
have in my c++ program to the python function. So I'm looking for a way 
to get a function pointer that I can pass two numbers and that returns a 
double. I hope I made myself clear - can anyone help me? Thanks in advance.

cheers,

roel