#include <iostream>
#include <utility>
#include <tuple>
 
template<typename Ret, typename... Ts, size_t... I>
Ret callFunction_(Ret (*fn)(Ts...), std::tuple<Ts...> tup, std::index_sequence<I...>)
{
    return fn(std::get<I>(tup)...);
}
 
template<typename Ret, typename... Ts, typename Tuple>
Ret callFunction(Ret (*fn)(Ts...), Tuple&& tup)
{
    return callFunction_(fn, std::forward<Tuple>(tup),
    	std::make_index_sequence<std::tuple_size<Tuple>{}>{});
}
 
int foo(int x, int y) {return x * y;}
 
int main()
{
    auto i = callFunction(foo, std::make_tuple(2, 3));
    std::cout << i;
}

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