Re: Explicit Values for Enums

[Doug Cutting <cu...@apache.org>]

Changing the serialization of schemas to use schema-specified values
would be difficult to achieve in a compatible manner.  However
changing the values used in some programming languages might not be
difficult.  In Java the ordinal value is not user-specifiable, but in
C and C++ it is.  So such a schema property might be used by the C++
code generator.

Doug

On Sun, Jun 2, 2013 at 1:35 PM, William McKenzie
<ws...@cartewright.com> wrote:
> I did a few searches on Jira and couldn't find anything it, so apologies if
> this has been requested previously.
>
> It seems like it would be useful to allow an explicit value for enumeration
> members. I suppose the biggest argument against it would be that might have
> to be a breaking change to the schemas, since the current list of values is
> just an array of strings, but maybe it could be added as an optional schema
> field which would override the implicit sequential numbering.
>
> // Maybe?
> {
>      "type": "enum",
>      "name": "Roles",
>      "symbols": [ "Producer", "Consumer" ]
>      "values": [ 100, 101 ]
> }
>
> // This is just too ugly
> {
>      "type": "enum",
>      "name": "Roles",
>      "symbols": [ "Producer=100", "Consumer=101" ]
> }
>
> // Alternating strings and values? still pretty ugly.
> {
>      "type": "enum",
>      "name": "Roles",
>      "symbols": [ "Producer", 100,  "Consumer", 101 ]
> }
>
> ~Bill