How to provide custom structured bindings for the sorted view class

sorted_view_cpp17_custom_structured_bindings.cpp

namespace std
{
	// 1. provide tuple_element<I, sorted_view<...>>::type
	template <std::size_t I, class... Types>
	struct tuple_element<I, utl::sorted_view<Types...>>
	{
		using sorted_view_t = utl::sorted_view<Types...>;
		using type = typename sorted_view_t::template tuple_element_t<I>;
	};

	// 2. provide tuple_size<sorted_view<...>>
	template <class... Types>
	struct tuple_size<utl::sorted_view<Types...>>
	    : public integral_constant<size_t, sizeof...(Types)>
	{
	};
}

namespace utl
{
	// 3. provide a get<I>(sorted_view<...>) function
	template <std::size_t I, class... Types>
	auto get(sorted_view<Types...> const& sv)
	{
		return sv.template elem<I>();
	}
}