On Mon, Mar 11, 2024 at 10:07 AM Frederick Virchanza Gotham wrote:
>
> Although maybe I could have written a lambda or a template class to do
> away with the preprocessor macroes.


Here it is without the preprocessor macroes:

    template<typename Tuple, size_t I>
    class CastTo final {
        using tElem = tuple_element_t< I, remove_reference_t<Tuple> >;
        using tElem_NoRef = remove_reference_t<tElem>;
        inline static constexpr bool vElem_IsRef =
!is_same_v<tElem,tElem_NoRef>;
        inline static constexpr bool vElem_ShouldBeR =
is_rvalue_reference_v<tElem> || (!vElem_IsRef &&
!is_lvalue_reference_v<Tuple>);
    public:
        using type = conditional_t< vElem_ShouldBeR , tElem_NoRef&&,
tElem_NoRef& >;
    };

    template<typename Tuple, size_t I>
    using CastTo_t = CastTo<Tuple,I>::type;

    template<typename F, typename Tuple, size_t... I>
    constexpr decltype(auto) apply_perfectly_impl(F &&f, Tuple &&t,
index_sequence<I...>)
    {
        return invoke( forward<F>(f), static_cast< CastTo_t<Tuple,I>
>( get<I>(t) )... );
    }

I've left out the 'noexcept(noexcept(................))' on both
functions because it's so long.