Re: [Cbor] [EXTERNAL] Re: CBOR tag for RFC 3339 full-date values

I’d suggest the numeric date be restricted to integers. No floats, bignums, decimal fractions… Fractions of days can be represented by tag 0 or tag 1 using hours, minutes, seconds. 64-bit integer counts of days are large enough.

LL

> On Mar 11, 2020, at 9:57 AM, Mike Jones <Michael.Jones=40microsoft.com@dmarc.ietf.org> wrote:
> 
> I'm fine merging Jörg's numeric date tag into my draft, provided that the result is not a polymorphic tag, in which the value could be either a number or a string.  We should allocate separate tags for string date and numeric date, just as tags 0 and 1 are different, and not polymorphic.
> 
> If this works for everyone, I'll add the numeric date tag with proposed value 'd' into my draft.
> 
> 				-- Mike
> 
> -----Original Message-----
> From: CBOR <cbor-bounces@ietf.org> On Behalf Of Carsten Bormann
> Sent: Wednesday, March 11, 2020 9:51 AM
> To: "Richter, Jörg" <Joerg.Richter@pdv-FS.de>; Mike Jones <Michael.Jones=40microsoft.com@dmarc.ietf.org>
> Cc: cbor@ietf.org; Anthony Nadalin <tonynad@microsoft.com>
> Subject: [EXTERNAL] Re: [Cbor] CBOR tag for RFC 3339 full-date values
> 
> Hi Joerg, Mike,
> 
> we discussed the date tag proposals at the CBOR interim today.
> The meeting consensus was that we should merge the date tag part of Joerg’s specification (i.e., both textual and numeric date references) with Mike’s draft, and spend a 1+1 tag (which would indeed conveniently be tag 100 = ‘d’).
> 
> I would like to work with the two of you to generate a -01 of Mike’s draft with text from Joerg, for discussion on May 25th (or whatever replacement we find for the physical IETF107 meeting.)
> 
> (We would look at time-of-day and timezone right after registering the date tag from -01; maybe in a -02.  My personal view would be that the time-of-day tag from Joerg would go right in, but we might want to go for a 1+2 tag for timezone [29818 for ’tz’ maybe?].  But let’s discuss this when we are there.)
> 
> Is that a good way forward?
> 
> Grüße, Carsten
> 
> 
>> On 2020-03-11, at 16:25, Carsten Bormann <cabo@tzi.org> wrote:
>> 
>> Hi Joerg,
>> 
>> I’m sorry we didn’t handle your requests properly.
>> Let’s try to fix this now.
>> 
>>> On 2020-03-04, at 08:42, Richter, Jörg <Joerg.Richter@pdv-FS.de> wrote:
>>> 
>>> Hi,
>>> 
>>>> The need for a date (not time) tag has come up before; I just can’t remember where.
>>> 
>>> One year ago I sent a proposal für a date tag [1].
>>> So far it has not made it into the overview of the assigned CBOR-tags [2].
>>> 
>>> I would very much appreciate if the suggested tag number is used for the date-tag, since we already use it internally.
>> 
>> What I like about Mike’s draft is that he references RFC 3339, which already is an established specification for how to write dates textually.  For that half of the proposal, I don’t think there is a technical difference with your proposal (except that Mike suggested a different tag number).  Beyond Mike’s draft, we would need to decide that we like to use the same tag with an epoch-based numeric date.  I think this is OK; it just requires users of the tag to specify which of the internal structures (or both) they would accept.  Note that we are running into the same issue with tag 1 (as used in EAT in the RATS WG), so that may help accepting that this is a normal thing to so.
>> 
>>> What is missing for the suggested tag numbers to be assigned?
>> 
>> I think we just have to make the decision to spend the 1+1 (short) tag.
>> That becomes somewhat easier with including the numeric date, because that is indeed quite compact and merits a short tag.
>> 
>>> Btw. I have another proposal for currencies and money amounts at [3] whose tags were not assigned either.
>> 
>> Let’s get to that, too, right after we are done with the date tag.
>> 
>> Grüße, Carsten
>> 
>> 
>>> - Jörg
>>> 
>>> [1] https://j-richter.github.io/CBOR/date.html
>>> [2] https://www.iana.org/assignments/cbor-tags/cbor-tags.xhtml
>>> [3] https://j-richter.github.io/CBOR/currency.html
>>> 
>> 
> 
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