Re: UTC or not UTC for timestamps in the past ([FEATURE REQUEST] Timezone support in org-mode)

[Thomas S. Dye]

Aloha Ihor,

Ihor Radchenko <yantar92@posteo.net> writes:

> "Thomas S. Dye" <tsd@tsdye.online> writes:
>
> > > I understand above that it is easier understandable when 
> > > reading
> > > [2023-01-22 Sun 08:29@+1100] as it is assumed by poster (I 
> > > guess 
> > > Max)
> > > that user will understand that there is +11 hours ahead.
> > Yes, the offset here is ambiguous--is it offset from some 
> > timezone 
> > or from UTC?
>
> It is not ambiguous if the user is familiar with standard time 
> format.
> The representation above is derived from
> https://en.wikipedia.org/wiki/ISO_8601, which allows the 
> following:
>
>     <time>Z
>
>     If the time is in UTC, add a Z directly after the time 
>     without a space.
>     Z is the zone designator for the zero UTC offset. "09:30 
>     UTC" is
>     therefore represented as "09:30Z" or "T0930Z". "14:45:15 
>     UTC" would be
>     "14:45:15Z" or "T144515Z".
>
>     <time>±hh:mm
>     <time>±hhmm
>     <time>±hh
>
>     The UTC offset is appended to the time in the same way that 
>     'Z' was
>     above, in the form ±[hh]:[mm], ±[hh][mm], or ±[hh].
>
>     Negative UTC offsets describe a time zone west of UTC±00:00, 
>     where the
>     civil time is behind (or earlier) than UTC so the zone 
>     designator will
>     look like "−03:00","−0300", or "−03".
>     
>     Positive UTC offsets describe a time zone at or east of 
>     UTC±00:00, where
>     the civil time is the same as or ahead (or later) than UTC 
>     so the zone
>     designator will look like "+02:00","+0200", or "+02".

Got it.  Thanks for the full explanation!  The ambiguity I 
mentioned was due to my ignorance of the time standard format 
variants.

> > Here is a proposal for a terminology of events that honors 
> > Ramsey's distinction between events and occurrences and hopes 
> > to 
> > cover all of Org's use cases.
> > ...
> > ...
> > The Org user should be able to toggle timestamp representation. 
> > In the case of a no-host event, user might toggle between UTC 
> > and 
> > local time.  In the case of situated or itinerant event, user 
> > might toggle among UTC, local time, and local time at the event 
> > site.
>
> Instead of toggling, would it be better to echo the different 
> formats
> like eldoc does + mouse-echo?

Or both?  Toggling globally and echoing individually, IIUC?

All the best,
Tom

--
Thomas S. Dye
https://tsdye.online/tsdye