On Wed, 28 Jul 2021 at 20:16, Kyle Knoepfel via Std-Proposals <
std-proposals_at_[hidden]> wrote:

> Hi Barry,
>
> Right...which is why I said the return type of value_for(...) would not be
> quite like std::optional. So there seem to be four or five options to me:
>
> 1. std::map<K, V>::value_for(K const&) -> typename std::map<K,
> V>::value_handle, where map gains a nested type that behaves like
> std::optional<V&> would behave. Yuck.
> 2. std::map<K, V>::value_for(K const&) -> V*, where a bare pointer, or
> some equivalent, is returned. Also yuck.
> 3. std::map<K, V>::value_for(K const&) -> std::optional<V&>. Requires
> convincing the standards committee to support reference-type template
> arguments for std::optional.
> 4. Something else I haven't thought of
> 5. Stop wanting this feature
>
> I think 3 is the ideal solution, but the most unlikely to occur. Option 1
> is doable but I assume no one wants to add an additional type to std::map.
> I fear 5 is the most likely solution, although it would sadden me.
>

4. optional<reference_wrapper<V>>?