It is very far along, though completed, couldn't be integrated before the cutoff date.

https://github.com/cplusplus/papers/issues/1161

Similar to function_ref there is interest in national body comments to ask for function_ref to get in somehow even though it too was punted to C++26. I am unfamiliar with the national body comments process but it would be wonderful if the following could be considered.

function_ref: The changes over the past year were mainly dangling fixes and primary use case enhancements. Otherwise the core contents of the paper was ready over a year ago.
monadic functions for expected: are purely the addition of a few functions
mdarray is similarly complete and had been tracking last minute changes to mdspan, container and last minute deletions
#embed is going into C23 though it was originally proposed for C++; I couldn't think of a greater testament to the ongoing cooperation to the C and C++ communities if there was a simultaneous release.
lazy is so anemic that it is practically a tag class

peanut butter is to jelly as
move_only_function is to function_ref, as
mdspan is to mdarray, as
generator is to lazy

While I wouldn't want any of the former to be delayed, I would be elated if exceptions were made for the laters.

There is also, seemingly, a backlog on somewhat completed language features.

Needless to say if none of these somehow make it into C++23, C++26 is going to be a good release before we even get to the good stuff. However, I would rather see C++23 made as great as it could reasonably be in remembrance of any fallen comrades during this COVID release and a testament to our tenacious spirit to persevere despite the loss of the annual meetings and conferences.





On Tue, Oct 18, 2022 at 2:32 PM Oleksandr Koval via Std-Proposals <std-proposals@lists.isocpp.org> wrote:
https://wg21.link/P2505

On Tue, Oct 18, 2022 at 9:27 PM Shiroki Satsuki via Std-Proposals <std-proposals@lists.isocpp.org> wrote:
'std::expected' adds a nice way of handling errors without using the
exception system and will be included in C++ 23. 'std::optional' is
going to have monadic operations in this version too.

However, the current 'std::expected' proposal
(https://wg21.link/p0323r10) makes no mention of monadic operations,
neither 'transform' (aka 'map') nor 'and_then' (aka 'bind' or
'flatMap'). A generic associated types 'rebind<U>' is included, though.

It would be a pity if functional programming lovers must wait until C++
26 for a complete 'Either' monad.




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Regards,
Oleksandr Koval.
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