Operator overloading problems with Python 2.1 and gcc 3.0

From: jfo60540_at_[hidden]
Date: 2001-07-26 10:55:35

Hi -
 
I am new to boost.python. I compiled the library with Python 2.1.1 and
gcc
3.0 under Solaris 2.7. There were a few minor problems (gcc stl
headers
are broken and std::sin(float) and std::cos(float) are left undefined
),
but I eventually  got all the tests (in particular comprehensive.py)
to
work properly. I then tried the following code to test
the operator overloading feature:
 
 
#include <iostream>
 
class vector {
     protected:
         int x;
         int y;
     public:
       vector(int a=0,int b=0) {
         x = a;
         y = b;}
       void set_values(int a, int b) {
         x=a;
         y=b;}
       vector operator+ (const vector operand) {
         vector z;
         z.x = x + operand.x;
         z.y = y + operand.y;
         return z;}
       vector operator- (const vector operand) {
         vector z;
         z.x = x - operand.x;
         z.y = y - operand.y;
         return z;}
};
 
#include <boost/python/class_builder.hpp>
namespace python = boost::python;
BOOST_PYTHON_MODULE_INIT(over)
{
  try
  {
    python::module_builder over("over");
    python::class_builder<vector> vector_class(over, "vector");
    vector_class.def(python::constructor<int,int>());
    vector_class.def(&vector::set_values, "set_values");
    vector_class.def(boost::python::operators<(boost::python::op_add |
boost::python::op_sub)>());
  }
  catch(...)
  {
    python::handle_exception(); // Deal with the exception for Python
  }
}
 
 
Compilation of the above fails with the following error messages:
 
/usr/local/ap/include/boost/python/operators.hpp: In member function
`PyObject*
   boost::python::detail::define_operator<2>::operator_function<Left,
   Right>::do_call(PyObject*, PyObject*) const [with Left = const
vector&,
   Right = const vector&]':
/usr/local/ap/include/boost/python/detail/extension_class.hpp:861:  
instantiated from here
/usr/local/ap/include/boost/python/operators.hpp:295: passing `const
vector' as
   `this' argument of `vector vector::operator-(vector)' discards
qualifiers
/usr/local/ap/include/boost/python/operators.hpp: In member function
`PyObject*
   boost::python::detail::define_operator<1>::operator_function<Left,
   Right>::do_call(PyObject*, PyObject*) const [with Left = const
vector&,
   Right = const vector&]':
/usr/local/ap/include/boost/python/detail/extension_class.hpp:861:  
instantiated from here
/usr/local/ap/include/boost/python/operators.hpp:294: passing `const
vector' as
   `this' argument of `vector vector::operator+(vector)' discards
qualifiers
 
 
Any help would be appreciated.