Poco::Optional iterator to enable "for-each" syntax about poco HOT 2 CLOSED

Poco::Optional and Poco::Nullable need a review and reimplementation.

I'd say, since std::optional is part of the standard since c++17, Poco::Optional and Poco::Nullable should be implemented in terms of it (current implementations are inefficient anyways, could/should have been implemented with pointer and the bool flag "wart" avoided; NullType could have been nullptr_t, but even as it is it could have at least been static const).

C++23 adds monadic operations; if I'm understanding it right, that's what you are looking for. We did not yet move to C++23, so we can't introduce it internally at this time, but you could implement those and they can be replaced later once we move to C++23. Does that help?

/cc @matejk

from poco.

I guess Poco::Optional is only really interesting if it's offering an alternative for users of C++14 and earlier. If the project is just targeting C++17 and up, it's probably not really interesting to develop this further. Maybe I'll just create some kind of iterator adapter to scratch my own itch.

from poco.