template <int... Is>
struct int_range {};

template <int N, int... Is>
struct make_int_range : make_int_range<N - 1, N - 1, Is...> {};

template <int... Is>
struct make_int_range<0, Is...> : int_range<Is...> {};

/**
 * Private/internal, don't use
 */
template <class Lambda, int... Is>
auto _make_function(const Lambda& f, int_range<Is...>) -> void /*TODO*/ {
        typedef function_traits<Lambda> traits;
        return std::function<typename traits::return_type(typename traits::template arg<Is>::type...)>(f);
}

/**
 * Lambda to std::function
 */
template <class Lambda>
auto make_function(const Lambda& f) -> void  { //TODO std::function<function_traits<Lambda>::return_type(function_traits<Lambda>::args)> {
        typedef function_traits<Lambda> traits;
        return _make_function(f, make_int_range<function_traits<Lambda>::arity>());
}