Enums, bitfields and wl_arrays

[Pekka Paalanen]

On Tue, 13 Oct 2015 20:27:58 +0100
Auke Booij <auke at tulcod.com> wrote:

> On 13 October 2015 at 16:19, Solerman Kaplon <solerman at gmail.com> wrote:
> > Em 13-10-2015 11:35, Nils Chr. Brause escreveu:
> >>
> >> In C++ the order doesn't matter either, since each entry has a defined
> >> value. I wonder why this is different in Java?

> I really don't understand this discussion. Is the claim that the usage
> of enums in java is problematic, because inserting a new value in an
> existing enum might change the index of later values, thereby creating
> an inconsistency?

Yes, this is how I understood the problem from the irc discussion,
indeed.

> If so, all I can say that clearly the object you want to associate
> with wayland-style enums is not whatever Java has invented for an
> "enum". The values that are associated to names inside wayland enums
> are very clear-defined, and if a language cannot safely couple names
> back to values, then that is a language that does not understand the
> concept of a variable. If this is a fundamental problem about Java
> enums, you better find a way around it, but I don't see how this is in
> any way a problem on the wayland side: there are enums, and enums
> contain names, and those names have values.
> 
> But if this is indeed the issue you are discussing, then this must
> have already been a problem before the introduction of additional XML
> attributes.
> 
> Can we agree on the following? Until there is any firm specification
> of open/closed enums, every enum should be considered open, and
> although some legal values might be listed, others might not be, and
> some might only be legal sometimes. New values may be added (but not
> changed or removed) to protocol specifications without introducing any
> compatibility issues.

FWIW, I would be happy with that.

Solerman, you forgot to reply-to-all. I added back the CCs.


Thanks,
pq
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