#include <boost/parameter.hpp>

BOOST_PARAMETER_NAME(arg1)
BOOST_PARAMETER_NAME(arg2)

using namespace boost::parameter;

struct callable2
{
    BOOST_PARAMETER_CONST_MEMBER_FUNCTION(
        (void), call, tag, (required (arg1,(int))(arg2,(int)))
    )
    {
        call_impl(arg1, arg2);
    }

 private:
    void call_impl(int, int); // implemented elsewhere.
};