Time zone: the next generation

Mark Davis mark.davis at jtcsv.com
Mon Mar 7 17:34:17 UTC 2005


----- Original Message ----- 
From: "Paul Eggert" <eggert at CS.UCLA.EDU>
To: "Deborah Goldsmith" <goldsmit at apple.com>
Cc: "Tz (tz at elsie.nci.nih.gov)" <tz at lecserver.nci.nih.gov>
Sent: Sunday, March 06, 2005 23:04
Subject: Re: Time zone: the next generation

> Deborah Goldsmith <goldsmit at apple.com> writes:
> > On Mar 6, 2005, at 1:45 AM, Paul Eggert wrote:
> >> (6)  Do we add support to represent time zone abbreviations in other
> >>      locales, e.g., HNE for Eastern Standard Time for French writers?
> >
> > That data is already in CLDR [1].
> Some of the data is there, but as far as I can tell there's no
> programmatic way to generate the proper information from the union of
> CLDR and the tz database.
> To take an extreme example, the abbreviation "LMT" can mean either
> "Local Mean Time" or "Lisbon Mean Time", and as far as I can see the
> CLDR infrastructure provides no way to tell which is which for
> Europe/Lisbon time stamps.  The tz data currently show that Portuguese
> time stamps before 1884 used local mean time, and that from 1884-1911
> they used Lisbon Mean Time, but the only think you'll find in the tz
> database proper, outside of comments, is "LMT" for both.  This sort of
> thing is why I think it advisable to add better support for time zone
> abbreviations.

While CLDR does provide for the option of having timezone abbreviations,
what we have found is that they seldom used, except in the multi-zone
countries, like the US, Canada, Australia, etc, and in that case, typically
just in the languages that are used in that country. Even there there is a
problem, because often the abbreviations used in one country will collide
with those used in another. So while it is available, it doesn't appear
worth encouraging.

> Caveat: the CLDR database
> <http://www.unicode.org/cldr/data/diff/by_type/dates_timeZoneNames.html>
> currently doesn't have any entries either for Lisbon or for local mean
> time, so to some extent I'm guessing about how the CLDR would actually
> operate once it became complete enough to handle the Portuguese situation.
> > doing so would require adding a lot of infrastructure to handle
> > localization.
> Yes.  It would be nice if we could simply point people at CLDR, and
> address the problem mentioned above.  Ideally we could point them to a
> complete reference implementation (such as already exists for tz), one
> that would handle the combined tz+CLDR problem.

We have been collecting timezone information in this release, but the way it
works is that if a country only has a single timezone, the default is to use
the name of the country itself, which we already have in a large number of
languages. So you would not see a specific timezone localization for Lisbon
unless that was felt to be important in some particular language.

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