Subject: Re: [boost] variant2 never empty guarantees (was: Re: Outcome/expected/etc/etc/etc)
From: Peter Dimov (lists_at_[hidden])
Date: 2017-06-08 13:01:07
> Gottlob Frege wrote:
>
> > Agreed. But I don't see much value in the never-empty guarantee if it
> > doesn't give you the strong guarantee.
>
> I'm not sure I understand this fully; could you please explain from what
> expressions, and under what conditions, you expect the strong guarantee?
>
> variant<X, Y> v1, v2;
> X x;
>
> v1= v2; // do you expect strong guarantee here?
> v1 = std::move(v2); // here?
> v1 = x; // here?
> v1 = std::move(x); // here?
> v1.emplace<X>(); // here?
Anyone? This is a genuine inquiry. How can I give you strong guarantee if
you don't tell me when and where you want it?