#include <iostream>
#include <boost/preprocessor.hpp>

const int value1 = 10;
const int value2 = 2;

int       func1() { return 5; }
int       func2() { return 2; }

#define template_expr(arg1, arg2) std::cout << arg1 + arg2() << std::endl

#define ParamSet1() (value1, func1)
#define ParamSet2() (value2, func2)

#define instantiate(expr, set_number) BOOST_PP_EXPAND(expr ParamSet##set_number())

#define instantiate_by_name(expr, set_name) BOOST_PP_EXPAND(expr set_name())

int main()
{
    instantiate(template_expr, 1); // std::cout << value1 + func1() << std::endl;
    instantiate_by_name(template_expr, ParamSet2); // std::cout << value2 + func2() << std::endl
}