About the 2 ways of adding an enum: The user can always specify an error handler to handle unknown values. The error handle can then handle the error value, or unknown value.
On Mon, 27 Apr 2015 09:05 Pekka Paalanen <ppaala...@gmail.com> wrote: > On Sat, 25 Apr 2015 14:11:32 +0000 > Jeroen Bollen <jbin...@gmail.com> wrote: > > > > I think that totally depends on how the interface is specified. This > > > applies only to one of the two ways an <enum> can grow. > > > > What other way can it grow? It can only grow bigger. If the application > > isn't aware of new values added, it should output a warning or an error. > > These: > > On Wed, 22 Apr 2015 09:34:51 +0300 > Pekka Paalanen <ppaala...@gmail.com> wrote: > > > There are two ways to add values to an existing <enum>: > > > > - Bumping the interface version, and ensuring the new values are used > > only with the appropriate runtime interface version. > > > > - From the first definition of an interface, specify how unknown values > > should be handled. Otherwise users do not expect unknown values to > > appear. > > The latter case is where you do not want an automatic always-on warning > or error. > > > > On Fri, 24 Apr 2015 22:05 Bill Spitzak <spit...@gmail.com> wrote: > > > > > Since all the codegen packages that want to use this enum attribute > have > > > not been written yet I don't think back-compatibility is an issue. They > > > are not using uint because they do not exist yet! > > Except if you happen to have an old libwayland which you develop your > 3rd party app against, for instance because you use a distribution that > does not include a more recent version yet. > > Depending on the language, I suppose the breakage could go both ways? > Is there a language where an enum is not allowed to be implicitly > converted to a uint or int? > > > Thanks, > pq > > > > The C codegen can continue to ignore the enum, or use it in a way that > > > does not break code that tries to pass an integer or the wrong enum. > > > > > > On 04/24/2015 12:07 AM, Pekka Paalanen wrote: > > > > > > > The purpose of docenum was purely for documentation. An API generator > > > > must ignore all docenum annotations. This was the backward-compatible > > > > addition. > > > > > > > > Any attribute that modifies the generated API in incompatible ways > > > > cannot be added after the interface has been released as stable. If > > > > your function argument was uint, and you change it to an enum in a > > > > strictly typed language, does it not have a good chance of breaking > > > > someone's build? > > > > >
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