>
> Isn't it too low-level? How well does it *capture intent* and *how
> readable it is*? I do not think I want to *transform* anything (I just
> want to have a couple of checks)...
>

When you're starting with optional<UserId> and end with optional<string> then
you practically do a transform, even if you don't call it that.
It's like using standard algorithms instead of raw for loops.