You need to build a parameter pack of numbers and unpack them
template<int ...>
struct seq { };
template<int N, int ...S>
struct gens : gens<N-1, N-1, S...> { };
template<int ...S>
struct gens<0, S...> {
typedef seq<S...> type;
};
// ...
void delayed_dispatch() {
callFunc(typename gens<sizeof...(Args)>::type());
}
template<int ...S>
void callFunc(seq<S...>) {
func(std::get<S>(params) ...);
}
// ...