Re: [Cbor] A CBOR tag for alternatives/unions, request for comments

Carsten Bormann <cabo@tzi.org> Wed, 23 February 2022 13:16 UTC

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From: Carsten Bormann <cabo@tzi.org>
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Date: Wed, 23 Feb 2022 14:16:14 +0100
Cc: Alexander Byaly <alexander.byaly@iohk.io>, Jared Corduan <jared.corduan@iohk.io>
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To: Michael Peyton Jones <michael.peyton-jones@iohk.io>, Duncan Coutts <duncan@well-typed.com>, cbor@ietf.org
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Subject: Re: [Cbor] A CBOR tag for alternatives/unions, request for comments
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I finally got around to integrate the proposal by Duncan Coutts and Michael Peyton Jones to allocate tags for enumerated alternative data items into notable-tags.

https://www.ietf.org/archive/id/draft-bormann-cbor-notable-tags-06.html#name-enumerated-alternative-data

I took the liberty to suggest tag 101 (‘e’) for the extended case.
I also made the cases non-overlapping, as this simplifies deterministic encoding (and interop testing in general).

Current state of tag allocation:
range  used     %                 free                total
0 1+0    12 50.00                   12                   24
1 1+1    62 26.72                  170                  232
2 1+2    45  0.07                65235                65280
3 1+4     3  0.00           4294901757           4294901760
4 1+8     2  0.00 18446744069414584318 18446744069414584320

If we have time in the CBOR meeting today (very likely) and you have time and comments, we could complete the discussion and ask IANA to register.

Coordinates of the CBOR meeting are below.
You’ll need an IETF datatracker account to participate; you can do that here:

https://datatracker.ietf.org/accounts/create/

I’m out of English words to apologize for my tardy treatment of this matter (and for the late notice of the meeting in 100 minutes).

Grüße, Carsten


The next CBOR WG Virtual Meeting is this Wednesday, 23 Feb, at 15:00
UTC.  Information for this meeting is here:

Datatracker: https://datatracker.ietf.org/meeting/interim-2022-cbor-04/session/cbor
Notes: https://notes.ietf.org/notes-ietf-interim-2022-cbor-04-cbor
Meetecho: https://meetings.conf.meetecho.com/interim/?short=9d38d4c9-cf9e-48c3-bc25-97b025698ec0