Re: POSIX TS spec reverses the meaning of TZ offset compared to ISO (was: [POLL] Proposed syntax for timestamps with time zone info

[Ihor Radchenko <yantar92@posteo.net>]

Heinz Tuechler <tuechler@gmx.at> writes:

> Same for me, I usually see ISO offset. Further, I am used to exchange
> time designations (CET, EST, PDT,...) instead of [continent/city]
> timezone names.

While I see a push towards using time zone abbreviations, we should not
make them a part of the syntax.

If we take a look at https://en.wikipedia.org/wiki/List_of_time_zone_abbreviations
it states:

    Time zones are often represented by alphabetic abbreviations such as
    "EST", "WST", and "CST", but these are not part of the international
    time and date standard ISO 8601 and their use as sole designator for
    a time zone is discouraged. Such designations can be ambiguous; for
    example, "CST" can mean China Standard Time (UTC+8), Cuba Standard
    Time (UTC−5), and (North American) Central Standard Time (UTC−6),
    and it is also a widely used variant of ACST (Australian Central
    Standard Time, UTC+9:30). Such designations predate both ISO 8601
    and the internet era; in an earlier era, they were sufficiently
    unambiguous for many practical uses within a national context (for
    example, in railway timetables and business correspondence), but
    their ambiguity explains their deprecation in the internet era, when
    communications more often cannot rely on implicit geographic context
    to supply part of the meaning.

The best we can do is supply a completion dialogue and using TZ POSIX
format that is able to understand "SOMERANDOMZONENAME+07" disregarding
the unknown zone and only using the offset.

> ...My impression is that many of non experts like me don't
> know in which time zone they are living. Is it trivial to find the
> [continent/city] timezone name to a specific place?

If you don't need to worry about time zones than honestly you probably
don't need time zones in your timestamps. And at least you know the UTC
offset, don't you? Time zone abbreviation will gain you nothing if you
know UTC offset because time zone abbreviations don't code information
about the daylight savings and the likes.

-- 
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
Support Org development at <https://liberapay.com/org-mode>,
or support my work at <https://liberapay.com/yantar92>