on.cc

#include <iostream>
#include <tr1/functional>

template <typename F, typename G>
class on_class
  : public std::binary_function<typename G::argument_type,
      typename G::argument_type, typename F::result_type>
{
  private:
    F f;
    G g;
  public:
    on_class(const F& f_, const G& g_)
      : f(f_), g(g_)
    {}

    typename F::result_type
    operator()(const typename G::argument_type& x, const typename G::argument_type& y) const
    {
      return f(g(x), g(y));
    }
};

template <typename F, typename G>
on_class<F, G>
on(const F& f, const G& g)
{
  return on_class<F, G>(f, g);
}

int main()
{
  const std::tr1::function<int (int,int)> f = on(std::plus<int>(), std::negate<int>());
  std::cout << f(3, -5) << std::endl;
  return 0;
}