Function enum_for_each

include/magic_enum/magic_enum_utility.hpp:67–78

template <typename E, detail::enum_subtype S = detail::subtype_v<E>, typename F, detail::enable_if_t<E, int> = 0>
constexpr auto enum_for_each(F&& f) {
  using D = std::decay_t<E>;
  static_assert(std::is_enum_v<D>, "magic_enum::enum_for_each requires enum type.");
  static_assert(detail::is_reflected_v<D, S>, "magic_enum requires enum implementation and valid max and min.");
  constexpr auto sep = std::make_index_sequence<detail::count_v<D, S>>{};

  if constexpr (detail::all_invocable<D, S, F>(sep)) {
    return detail::for_each<D, S>(std::forward<F>(f), sep);
  } else {
    static_assert(detail::always_false_v<D>, "magic_enum::enum_for_each requires invocable of all enum value.");
  }
}

template <typename E, detail::enum_subtype S = detail::subtype_v<E>>
[[nodiscard]] constexpr auto enum_next_value(E value, std::ptrdiff_t n = 1) noexcept -> detail::enable_if_t<E, optional<std::decay_t<E>>> {