Function select

extlibs/sol3/include/sol/sol.hpp:17702–17744

		template <bool is_yielding, typename Fx, typename... Args>
		void select(lua_State* L, Fx&& fx, Args&&... args) {
			using uFx = meta::unqualified_t<Fx>;
			if constexpr (is_lua_reference_v<uFx>) {
				// TODO: hoist into lambda in this case for yielding???
				stack::push(L, std::forward<Fx>(fx), std::forward<Args>(args)...);
			}
			else if constexpr (is_lua_c_function_v<uFx>) {
				int upvalues = 0;
				upvalues += stack::push(L, nullptr);
				upvalues += stack::push(L, std::forward<Fx>(fx));
#if defined(SOL_NOEXCEPT_FUNCTION_TYPE) && SOL_NOEXCEPT_FUNCTION_TYPE
				if constexpr (std::is_nothrow_invocable_r_v<int, uFx, lua_State*>) {
					detail::lua_CFunction_noexcept cf = &lua_c_noexcept_wrapper<is_yielding>;
					lua_pushcclosure(L, reinterpret_cast<lua_CFunction>(cf), 2);
				}
				else {
					lua_CFunction cf = &lua_c_wrapper<is_yielding>;
					lua_pushcclosure(L, cf, 2);
				}
#else
				lua_CFunction cf = &function_detail::lua_c_wrapper<is_yielding>;
				lua_pushcclosure(L, cf, 2);
#endif
			}
			else if constexpr (std::is_function_v<std::remove_pointer_t<uFx>>) {
				std::decay_t<Fx> target(std::forward<Fx>(fx), std::forward<Args>(args)...);
				lua_CFunction freefunc = &function_detail::upvalue_free_function<Fx, is_yielding>::call;

				int upvalues = 0;
				upvalues += stack::push(L, nullptr);
				upvalues += stack::stack_detail::push_as_upvalues(L, target);
				stack::push(L, c_closure(freefunc, upvalues));
			}
			else if constexpr (std::is_member_function_pointer_v<uFx>) {
				select_member_function<is_yielding>(L, std::forward<Fx>(fx), std::forward<Args>(args)...);
			}
			else if constexpr (meta::is_member_object_v<uFx>) {
				select_member_variable<is_yielding>(L, std::forward<Fx>(fx), std::forward<Args>(args)...);
			}
			else {
				select_convertible<is_yielding>(types<>(), L, std::forward<Fx>(fx), std::forward<Args>(args)...);
			}
		}
	} // namespace function_detail

	namespace stack {