template <size_t k>
struct ReturnArgAction {
template <typename... Args>
- auto operator()(const Args&... args) const ->
- typename std::tuple_element<k, std::tuple<Args...>>::type {
- return std::get<k>(std::tie(args...));
+ auto operator()(Args&&... args) const -> decltype(std::get<k>(
+ std::forward_as_tuple(std::forward<Args>(args)...))) {
+ return std::get<k>(std::forward_as_tuple(std::forward<Args>(args)...));
}
};
EXPECT_EQ("seven", a.Perform(std::make_tuple(5, 6, std::string("seven"), 8)));
}
+TEST(ReturnArgActionTest, WorksForNonConstRefArg0) {
+ const Action<std::string&(std::string&)> a = ReturnArg<0>();
+ std::string s = "12345";
+ EXPECT_EQ(&s, &a.Perform(std::forward_as_tuple(s)));
+}
+
TEST(SaveArgActionTest, WorksForSameType) {
int result = 0;
const Action<void(int n)> a1 = SaveArg<0>(&result);