Re: [Cbor] draft-ietf-cbor-date-tag-02 - handling of time zone offsets

[Juergen Schoenwaelder <[e-mail]>]

On Fri, Jul 03, 2020 at 09:05:50AM +0200, Carsten Bormann wrote:

[...]

> Counting calendar sheets ripped off the wall is rather unambiguous, though.
> 
> The problems that you are alluding to come from transitioning between the calendar day domain and the time anchored on a time scale domain; additional problems are caused with this when the time involves time zones that vary in world time offset.

You like to view a date as something entirely detached from the notion
of time. I am not sure what the use cases for this are, in particular
for computers.

I can see, however, a number of use cases where a date is associated
with a specific event and in these situations the date value is
ambiguous since multiple systems rightfully may assign different dates
to the same event (the same point in time). Hence, code comparing date
values or making calculations with them has to be careful that
surprises may happen.

/js

PS: There are even events where there is no natural time zone that can
    be associated with the event, like the first step on the moon.

-- 
Juergen Schoenwaelder           Jacobs University Bremen gGmbH
Phone: [phone]         Campus Ring 1 | 28759 Bremen | Germany
Fax:   [phone]         <https://www.jacobs-university.de/>