constexpr_map.cpp

#include <array>
#include <cstdio>

template <class Array, class F, class Seq>
struct map_impl;

template <class Array, class F, size_t... I>
struct map_impl<Array, F, std::index_sequence<I...>>
{
  template <class... Args>
  static constexpr Array run(Array const A, Args... args)
  {
    return Array{F::value(A[I], args...)...};
  }
};

template <class F, class T, size_t N, class... Args>
constexpr auto map(std::array<T,N> const A, Args... args)
{
  return map_impl<std::array<T,N>, F, decltype(std::make_index_sequence<N>())>::run(A, args...);
}

constexpr int f(int i) { return i+1; }

int main()
{
  constexpr std::array<int, 10> A = {0};
  constexpr auto B = map<std::integral_constant<decltype(&f), &f>>(A);
  for (int V: B) {
    printf("%d\n", V);
  }
  return 0;
}