smitherfield

  template<typename... Ts>
  class SoA : public tuple<vector<Ts>...> {
          // ...
          template<size_t... Is>
          tuple<Ts&...> subscript(size_t i, index_sequence<Is...>) {
                  return {get<Is>(*this)[i]...};
          }
  public:
          // ...
          auto operator[](size_t i) {
                  return subscript(i, index_sequence_for<Ts...>{});
          }
  };

  class Array
    def neighbor_sums
      map.with_index do |_, i|
        fetch(i - 1 & 0xFF_FF_FF_FF, 0) + fetch(i + 1, 0)
      end
    end
  end

  [1, 1, 1, 1].neighbor_sums # [1, 2, 2, 1]

  ios::sync_with_stdio(false);