was: Re: [tz] Propose new zone for Crozet Islands On Thu, May 24, 2012 at 10:40 AM, Philip Newton <philip.newton@gmail.com> wrote:
On Thu, May 24, 2012 at 9:46 AM, Tobias Conradi <tobias.conradi@gmail.com> wrote:
The rule in the Theory file can easier lead to double assignments of abbreviations
I don't think a particular effort is made to make the abbreviations be unique I don't know how you define "particular".
The provision to use ISO 3166-1 alpha-2 codes for several of them leads to several of them being unique. IIRC there have been emails on the mailing list caring about uniqueness, asking for assignment of another abbreviation to avoid ambiguity. ftp://ftp.iana.org/tz/data/australasia contains a longer text by Paul Eggert 2001-04-05 about uniqueness.
or even particularly meaningful. I don't know how you define "particularly".
ftp://ftp.iana.org/tz/code/Theory ----- Outline ----- Time and date functions Scope of the tz database Names of time zone rule files Time zone abbreviations Calendrical issues Time and time zones on Mars .... one of six main sections. The section "Time zone abbreviations" contains several rules. They all derive the abbreviation from some other string related to the time zone.
The main identifier is the "Europe/Berlin" type name, that is the IANA time zone name. IANA time zones are "cross year".
not the "CE(S)T" type one. that is the IANA abbreviation for the non-IANA, the "real world" time zone.
One can try to achieve uniqueness of the latter in any given year. The two uniquenesses can be achieved independently. But indeed there are some that are not unique, e.g.: * IST ** India ** Israel (Ephraim Silverberg 1988 invention, even happy about ambiguity: "I am happy to share timezone abbreviations with India, high on my favorite-country list (and not only because my wife's family is from India" ftp://ftp.iana.org/tz/data/asia ) * EST ** Australia ** US * CST ** Australia ** US * AST ** Arabia (Eggert invention 2006-03-22 ftp://ftp.iana.org/tz/data/asia) ** Aruba, Curacao, Trinidad and Tobago * GST ** Gulf (Eggert invention 2006-03-22 ftp://ftp.iana.org/tz/data/asia) ** South Georgia and the South Sandwich Islands Also ICT Indochina (Eggert invention 2006-03-22 ftp://ftp.iana.org/tz/data/asia) IC is a reserved ISO 3166-1 alpha-2 element for the Canary Islands. -- Tobias Conradi Rheinsberger Str. 18 10115 Berlin Germany http://tobiasconradi.com/