Re: [boost] variant2 never empty guarantees (was: Re: Outcome/expected/etc/etc/etc)

6 Jun 2017


      2017-06-06 15:38 GMT+02:00 Gottlob Frege via Boost :
...
On Tue, Jun 6, 2017 at 5:29 AM, Andrzej Krzemienski via Boost
 wrote:
...
You are basically saying: provide the implementation that gives me strong
guarantee when I meet condition X. ("X" being up to one type with
potentially throwing move constructor).
Your expectation is reasonable, but (I think) it is incompatible with
other
...
peoples' expectation: provide implementation that gives me never-empty
guarantee when I meet condition Y. ("Y" in that case means I have a type
with nothrow default constructor.)
I do not think both expectations can be satisfied in one implementation.
Regards,
&rzej;
Agreed.  But I don't see much value in the never-empty guarantee if it
doesn't give you the strong guarantee.
Exactly. I would like to see an example where a never-empty guarantee alone
adds value. Maybe this is just my lack of imagination.

Regards,
&rzej;