Re: [boost] [variant] Heads-up!

Subject: Re: [boost] [variant] Heads-up!
From: Matt Calabrese (rivorus_at_[hidden])
Date: 2019-04-29 20:35:18

On Mon, Apr 29, 2019 at 4:08 PM Nikita Kniazev via Boost
<boost_at_[hidden]> wrote:
>
> There seems to be misunderstanding of what the thread is about.
>
> The short sum-up of the changes: Nothing changed for users that does not
> use recursive variant. The changes were applied mainly for
> recursive_wrapper, and affect recursive variant indirectly.

Would your problems also be solved if there were a separate type,
different from recursive_wrapper, that is similar but explicitly has
an empty state (basically just a dynamic optional implementation, as
described in the other thread)? I believe this solves the performance
concerns without impacting existing users. The other suggestions on
how to do what you want without violating the never empty guarantee or
introducing a new valid state to recursive_wrapper would also be
positive regardless, imo.

-- 
-Matt Calabrese