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Re: [POLL] Proposed syntax for timestamps with time zone info (was: [FEA
From: |
Jean Louis |
Subject: |
Re: [POLL] Proposed syntax for timestamps with time zone info (was: [FEATURE REQUEST] Timezone support in org-mode datestamps and org-agenda) |
Date: |
Wed, 1 Feb 2023 11:32:16 +0300 |
User-agent: |
Mutt/2.2.9+54 (af2080d) (2022-11-21) |
* Tim Cross <theophilusx@gmail.com> [2023-02-01 11:10]:
> I think the confusion relates to context interpretation. If you see
> @Europe/Berlin in isolation, then it is ambiguous as it can refer to
> two different time zone definitions (standard v daylight savings).
Of course, without the time stamp, the time zone alone cannot give
time.
> However, if you consider it in conjunction with a date and time, as
> in 2023-03-23 02:30 @Europe/Berlin, then it isn't ambiguous - in
> that case, it really just says 'Lookup the time zone offset in the
> databse for Berlin as of that date and time.
Exactly that.
> Now that could change - for example, the German government might
> make a temporary or permanent change that would change the offset
> from UTC for that date+time the day after I look at it (or export
> it).
It cannot change in past.
It will not change drastically or capriciously as Germany aligns with
other countries and ISO standard.
It is more likely that ISO non-members deviate from international
coordination of time related definitions:
ISO - Members:
https://www.iso.org/members.html
> Personally, I cannot see the use case of including both a fully
> qualitifed time zone (as in @Europe/Berlin) and an offset, but I
> also don't know all possible use cases - there could well be use
> cases where you want/need to record both the location time zone as
> well as the offset at the point when you recorded the timestamp.
Time Zones vs. Offsets – What's the Difference? Which Is Best?:
https://spin.atomicobject.com/2016/07/06/time-zones-offsets/
Quoting:
--------
- Given a time zone and a UTC time, you can know the offset—and
therefore the local time.
- Given a local time and an offset, you can know UTC time, but you do
not know which time zone you’re in (because multiple timezones have
the same offset).
- Given UTC and an offset, you can know the local time.
- Given a time zone and an offset, you don’t know much.
- That’s why a calendar systems work with time zones, offsets, and
UTC;
- we need the offset to go from local time to UTC, and we need the
time zone to go from UTC to local time.
--
Jean
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- Re: [POLL] Proposed syntax for timestamps with time zone info (was: [FEATURE REQUEST] Timezone support in org-mode datestamps and org-agenda), tomas, 2023/02/01
- Re: [POLL] Proposed syntax for timestamps with time zone info (was: [FEATURE REQUEST] Timezone support in org-mode datestamps and org-agenda), Tim Cross, 2023/02/01
- Re: [POLL] Proposed syntax for timestamps with time zone info (was: [FEATURE REQUEST] Timezone support in org-mode datestamps and org-agenda),
Jean Louis <=
- Re: [POLL] Proposed syntax for timestamps with time zone info (was: [FEATURE REQUEST] Timezone support in org-mode datestamps and org-agenda), Ihor Radchenko, 2023/02/01
- Re: [POLL] Proposed syntax for timestamps with time zone info (was: [FEATURE REQUEST] Timezone support in org-mode datestamps and org-agenda), Tim Cross, 2023/02/01
- Re: [POLL] Proposed syntax for timestamps with time zone info (was: [FEATURE REQUEST] Timezone support in org-mode datestamps and org-agenda), Ihor Radchenko, 2023/02/01
- Re: [POLL] Proposed syntax for timestamps with time zone info (was: [FEATURE REQUEST] Timezone support in org-mode datestamps and org-agenda), Jean Louis, 2023/02/01
- Re: [POLL] Proposed syntax for timestamps with time zone info (was: [FEATURE REQUEST] Timezone support in org-mode datestamps and org-agenda), Ihor Radchenko, 2023/02/01
- Re: [POLL] Proposed syntax for timestamps with time zone info (was: [FEATURE REQUEST] Timezone support in org-mode datestamps and org-agenda), Max Nikulin, 2023/02/01
- Re: [POLL] Proposed syntax for timestamps with time zone info (was: [FEATURE REQUEST] Timezone support in org-mode datestamps and org-agenda), Jean Louis, 2023/02/01
- Re: [POLL] Proposed syntax for timestamps with time zone info (was: [FEATURE REQUEST] Timezone support in org-mode datestamps and org-agenda), Ihor Radchenko, 2023/02/01