zeus

0 /*

1 * Proof of concept C++23 exception interface shorthand

2 */

3

4 #include <functional>

5 #include <expected>

6 #include <string>

7

8

9 template <class Val, class Err, class... Args, class... CallArgs>

10 Val throwing_try(std::expected<Val, Err>(*func)(Args...), CallArgs&&... callargs) {

11 return std::invoke(func, std::forward<CallArgs>(callargs)...)

12 .or_else([](const auto& err) -> std::expected<Val, Err> {

13 throw err;

14 }).value();

15 }

16

17 template <class Val, class Err, class Type, class... Args, class... CallArgs>

18 Val throwing_try(std::expected<Val, Err>(Type::* func)(Args...), Type* self, CallArgs&&... callargs) {

19 return std::invoke(func, self, std::forward<CallArgs>(callargs)...)

20 .or_else([](const auto& err) -> std::expected<Val, Err> {

21 throw err;

22 }).value();

23 }

24

25 struct test {

26 std::expected<int, std::string> try_op(int x) {

27 if (x > 0) {

28 return x;

29 }

30 return std::unexpected{"op: value must be positive"};

31 }

32

33 auto op(int x) {

34 return throwing_try(&test::try_op, this, x);

35 }

36 };

37

38 int main() {

39 // return throwing_wrapper(op)(3);

40 test t;

41 return t.op(-54);

42 }`