[Cbor] Re: Private tag numbers / 1010

[Carsten Bormann <[e-mail]>]

On 15. Dec 2024, at 06:18, Anders Rundgren <[e-mail]> wrote:
> 
>> 
>> Regarding https://datatracker.ietf.org/doc/draft-rundgren-cotx/05/ of
>> tag 1010, please provide ability for identifier to be a non-text string
>> until this is not an RFC.
> 
> Well, for unknown reasons

(You can find discussion in the records of the mailing list.)

> the CBOR WG have rejected the by other formats firmly established method using dereferenceable specification URLs as object identifiers,

Actually, over in T2TRG we are looking at the subject of dereferenceable identifiers [1], so it’s not like we don’t care.  It just turned out there wasn’t a lot of appetite for URIs as type identifiers in the CBOR WG.
(Note that there is RFC 9090, which defines tags for another identifier scheme, ASN.1 OIDs, but didn’t go ahead to do the tag-1010-like type identifier/data item pairing — it apparently never occurred to us in the seven-year history of this RFC that this might be useful (*).)

So I wouldn’t use the term “rejected”, more like “not picked up”.
(It may have played a role that CBOR already has an excellent type identifier mechanism, the tag.)
And you did get the tag 1010 that does exactly what you specified it to do.

[1]: https://www.ietf.org/archive/id/draft-bormann-t2trg-deref-id-04.html
[2]: https://www.rfc-editor.org/rfc/rfc9090

> so it seems COTX will remain my private "invention" :)

I hope you don’t have patent claims on this; the tag registry is there for everyone to use.

> Anyway, I'm not a fan of "polymorphic" tags so I would urge you to seek a new tag number

Here I agree.

> (hopefully a bit more compact than 1010), for a version using a binary argument.

Well, “a binary argument” is not really very specific.
If we believe attaching type identifiers to data items is important, we should try to make them useful by being well-defined.

Grüße, Carsten

(*) Even knowing that ASN.1 has had ANY DEFINED BY since about 1984…