Re: C++17 skeleton with move semantics and std::variant

[Frank Heckenbach]

Hans Åberg wrote:

> Indeed. Others, may not want to patch their installations even it
> they can, as it may cause problems for other packages. Say if one
> writes package that uses a standard Bison installation, then it
> would be dangerous to patch it up with an experimental one.

Not really dangerous, as my C++17 patch only adds new files. (My other
patches change existing files, but they are rather small, and just
bugfixes.)

> >> But if someone uses their of variants type, would that require C++11?
> > 
> > Yes, the skeleton uses move semantics (i.e. rvalue references), so
> > C++11 is the minimum. (Not entirely sure if I accidentally used some
> > C++14 feature, as that's what I tested with besides C++17, but if
> > so, it may be rather easy to avoid.)
> 
> Would it in principle possible to use ones own variants that does
> not require C++11 and put the C++11 code within preprocessor
> directives so that it works for earlier C++ versions? - I am not
> sure there would be any use for this, just wondering.

Not (easily) with my patch, as it uses move semantics throughout.
For this use case, I think it would be easier to start with the
C++03 skeleton and change the variant implementation there.

Regards,
Frank