c++ template specify type after variadic types

type_after_variadic.cpp

// from https://www.cppstories.com/2020/09/variadic-pack-first.html/
namespace detail
{
  template<typename Output, typename... Inputs>
  void tempFunc(Output& output, Inputs const&... inputs)
  {
    // implementation of f
  }

  template<typename... InputsThenOutput, size_t... InputIndexes>
  void tempFunc(std::tuple<InputsThenOutput...> inputsThenOutputs, std::index_sequence<InputIndexes...>)
  {
    auto constexpr OutputIndex = sizeof...(InputsThenOutput) - 1;

    detail::tempFunc(std::get<OutputIndex>(inputsThenOutputs), std::get<InputIndexes>(inputsThenOutputs)...);
  }
}

// usage: tempFunc(input1, input2, input3, output);
template<typename... InputsThenOutput>
void tempFunc(InputsThenOutput&&... inputsThenOutput)
{
  detail::tempFunc(std::forward_as_tuple(inputsThenOutput...), std::make_index_sequence<sizeof...(inputsThenOutput) - 1>{});
}