Question on abbreviations

Mark Davis mark.davis at icu-project.org
Wed Sep 27 05:48:48 UTC 2006


I'm getting 3 strange cases when parsing the tz database, for the following
cases:

   - Didn't find %s values for M%sT under America/Phoenix:US for 1944 to
   1944
   - Didn't find %s values for C%sT under Asia/Macau:PRC for 1999 to +INF
   - Didn't find %s values for CE%sT under Europe/Warsaw:Poland for 1922
   to 1940

Let's take the first case. In the file northamerica, we have the following
lines.

Zone America/Phoenix    -7:28:18 -    LMT    1883 Nov 18 11:31:42
            -7:00    US    M%sT    1944 Jan  1 00:01
            -7:00    -    MST    1944 Apr  1 00:01
            -7:00    US    M%sT    1944 Oct  1 00:01
            -7:00    -    MST    1967
            -7:00    US    M%sT    1968 Mar 21
            -7:00    -    MST

Now, according to my reading of zic.8.txt, to see what the values for %s
are, we look at the rules that are in effect for the period in question. So
for the 2nd occurence of M%sT, we are concerned with the time between 1944
Apr  1 00:01 UNTIL 1944 Oct  1 00:01, according to the US rules. In the Rule
documentation, we have:

     LETTER/S
             Gives the "variable part" (for example, the "S" or
             "D" in "EST" or "EDT") of time zone abbreviations to
             be used when this rule is in effect.  If this field
             is -, the variable part is null.

So to get the value, we should look at the US rule that is in effect during
1944. Here are the US rules:

# Rule    NAME    FROM    TO    TYPE    IN    ON    AT    SAVE    LETTER/S
Rule    US    1918    1919    -    Mar    lastSun    2:00    1:00    D
Rule    US    1918    1919    -    Oct    lastSun    2:00    0    S
Rule    US    1942    only    -    Feb    9    2:00    1:00    W # War
Rule    US    1945    only    -    Aug    14    23:00u    1:00    P # Peace
Rule    US    1945    only    -    Sep    30    2:00    0    S
Rule    US    1967    2006    -    Oct    lastSun    2:00    0    S
Rule    US    1967    1973    -    Apr    lastSun    2:00    1:00    D
Rule    US    1974    only    -    Jan    6    2:00    1:00    D
Rule    US    1975    only    -    Feb    23    2:00    1:00    D
Rule    US    1976    1986    -    Apr    lastSun    2:00    1:00    D
Rule    US    1987    2006    -    Apr    Sun>=1    2:00    1:00    D
Rule    US    2007    max    -    Mar    Sun>=8    2:00    1:00    D
Rule    US    2007    max    -    Nov    Sun>=1    2:00    0    S

None of them are operant during 1944, so I don't find any value for M%sT. Am
I misreading something?

Mark


On 9/26/06, Paul Eggert <eggert at cs.ucla.edu> wrote:
>
> Steffen Thorsen <straen at thorsen.priv.no> writes:
>
> > Daylight Saving Time ended Friday for "Rule Palestine"
>
> Thanks for the heads-up.  Here is a proposed patch, which incorporates
> the Palestine change along with the other changes already proposed to
> this list recently.
>
> ===================================================================
> RCS file: RCS/africa,v
> retrieving revision 2006.12
> retrieving revision 2006.12.0.1
> diff -pu -r2006.12 -r2006.12.0.1
> --- africa      2006/09/18 16:58:11     2006.12
> +++ africa      2006/09/20 19:35:29     2006.12.0.1
> @@ -212,35 +212,13 @@ Rule      Egypt   1990    1994    -
> May      1      1:00    1:00
> # Go with IATA starting in 1995, except correct 1995 entry from 09-30 to
> 09-29.
> Rule   Egypt   1995    max     -       Apr     lastFri  0:00s  1:00    S
> Rule   Egypt   1995    2005    -       Sep     lastThu 23:00s  0       -
> -# From Hammad Hassan (2006-09-13), quoting The Egyptian Gazette
> (2006-09-10),
> -# issue no. 41,083, page 1, column 1:
> -# Egypt will switch back to the winter time on the eve of the first day
> of
> -# the Muslim holy month of Ramadan, expected to start this year on Sept.
> 24....
> -# "Clocks will be turned back starting from the night on which Darul Ifta
> ...
> -# announces sighting the crescent of the month of Ramadan,..." Magdi
> Radi,
> -# the Cabinet spokesman, said yesterday.
> -# From Hammad Hassan (2006-09-17):
> -# when we reach 1:00AM at Sep 25 the clocks will be turned back to
> 12:00AM.
> -# I think also this change will be this year and may be the next couple
> of
> -# years only.   (They just want to exclude Ramadan from the summer time;
> if
> -# so, the change will be among 3 years only if my calculations are
> correct).
> -# From Paul Eggert (2006-09-17):
> -# For now, assume a similar rule will be followed in 2006/2008, and that
> -# Ramadan will start as predicted by GNU Emacs 21.4.  Here's the code
> used
> -# to generate the 2006/2008 lines:
> -# (let ((year 1427))
> -#   (while (< year (+ 1427 3))
> -#     (let ((date (calendar-gregorian-from-absolute
> -#                 (calendar-absolute-from-islamic (list 9 2 year)))))
> -#      (insert (format "Rule\tEgypt\t%d\tonly\t-\t%s\t%2d\t 1:00\t0\t-\n"
> -#                      (extract-calendar-year date)
> -#                      (calendar-month-name (extract-calendar-month date)
> 3)
> -#                      (extract-calendar-day date))))
> -#     (setq year (1+ year)))))
> -Rule   Egypt   2006    only    -       Sep     25       1:00   0       -
> -Rule   Egypt   2007    only    -       Sep     14       1:00   0       -
> -Rule   Egypt   2008    only    -       Sep      3       1:00   0       -
> -Rule   Egypt   2009    max     -       Sep     lastThu 23:00s  0       -
> +# From Steffen Thorsen (2006-09-19):
> +# The Egyptian Gazette, issue 41,090 (2006-09-18), page 1, reports:
> +# Egypt will turn back clocks by one hour at the midnight of Thursday
> +# after observing the daylight saving time since May.
> +# http://news.gom.com.eg/gazette/pdf/2006/09/18/01.pdf
> +Rule   Egypt   2006    only    -       Sep     21      23:00s  0       -
> +Rule   Egypt   2007    max     -       Sep     lastThu 23:00s  0       -
>
> # Zone NAME            GMTOFF  RULES   FORMAT  [UNTIL]
> Zone   Africa/Cairo    2:05:00 -       LMT     1900 Oct
> ===================================================================
> RCS file: RCS/asia,v
> retrieving revision 2006.11
> retrieving revision 2006.11.0.3
> diff -pu -r2006.11 -r2006.11.0.3
> --- asia        2006/08/28 16:18:48     2006.11
> +++ asia        2006/09/26 17:55:21     2006.11.0.3
> @@ -1476,6 +1476,15 @@ Zone     Asia/Karachi    4:28:12 -       LMT
> 1907
> # Gaza changed as well, but presumed Gaza to follow the same rules as
> # the West Bank.
>
> +# From Steffen Thorsen (2006-09-26):
> +# according to the Palestine News Network (2006-09-19):
> +#
> http://english.pnn.ps/index.php?option=com_content&task=view&id=596&Itemid=5
> +# > The Council of Ministers announced that this year its winter schedule
> +# > will begin early, as of midnight Thursday.  It is also time to turn
> +# > back the clocks for winter.  Friday will begin an hour late this
> week.
> +# I guess it is likely that next year's date will be moved as well,
> +# because of the Ramadan.
> +
> # The rules for Egypt are stolen from the `africa' file.
> # Rule
> NAME    FROM    TO      TYPE    IN      ON      AT      SAVE    LETTER/S
> Rule EgyptAsia 1957    only    -       May     10      0:00    1:00    S
> @@ -1488,8 +1497,10 @@ Rule EgyptAsia   1966    only    -
> Oct      1      3:00    0
> Rule Palestine 1999    2005    -       Apr     Fri>=15 0:00    1:00    S
> Rule Palestine 1999    2003    -       Oct     Fri>=15 0:00    0       -
> Rule Palestine 2004    only    -       Oct      1      1:00    0       -
> -Rule Palestine 2005    max     -       Oct      4      2:00    0       -
> +Rule Palestine 2005    only    -       Oct      4      2:00    0       -
> Rule Palestine 2006    max     -       Apr      1      0:00    1:00    S
> +Rule Palestine 2006    only    -       Sep     22      0:00    0       -
> +Rule Palestine 2007    max     -       Oct     Fri>=15 0:00    0       -
>
> # Zone NAME            GMTOFF  RULES   FORMAT  [UNTIL]
> Zone   Asia/Gaza       2:17:52 -       LMT     1900 Oct
> @@ -1668,11 +1679,18 @@ Rule    Syria   1993    only    -       Sep
> 25      0:00    0       -
> # IATA SSIM (1998-02) says 1998-04-02;
> # (1998-09) says 1999-03-29 and 1999-09-29; (1999-02) says 1999-04-02,
> # 2000-04-02, and 2001-04-02; (1999-09) says 2000-03-31 and 2001-03-31;
> -# ignore all these claims and go with Shanks & Pottenger.
> +# (2006) says 2006-03-31 and 2006-09-22;
> +# for now ignore all these claims and go with Shanks & Pottenger,
> +# except for the 2006-09-22 claim (which seems right for Ramadan).
> Rule   Syria   1994    1996    -       Apr      1      0:00    1:00    S
> -Rule   Syria   1994    max     -       Oct      1      0:00    0       -
> +Rule   Syria   1994    2005    -       Oct      1      0:00    0       -
> Rule   Syria   1997    1998    -       Mar     lastMon 0:00    1:00    S
> Rule   Syria   1999    max     -       Apr      1      0:00    1:00    S
> +# From Stephen Colebourne (2006-09-18):
> +# According to IATA data, Syria will change DST on 21st September [21:00
> UTC]
> +# this year [only]....  This is probably related to Ramadan, like Egypt.
> +Rule   Syria   2006    only    -       Sep     22      0:00    0       -
> +Rule   Syria   2007    max     -       Oct      1      0:00    0       -
> # Zone NAME            GMTOFF  RULES   FORMAT  [UNTIL]
> Zone   Asia/Damascus   2:25:12 -       LMT     1920    # Dimashq
>                         2:00    Syria   EE%sT
> ===================================================================
> RCS file: RCS/southamerica,v
> retrieving revision 2006.3
> retrieving revision 2006.3.0.2
> diff -pu -r2006.3 -r2006.3.0.2
> --- southamerica        2006/04/03 14:07:15     2006.3
> +++ southamerica        2006/09/20 19:35:02     2006.3.0.2
> @@ -1064,6 +1064,10 @@ Rule     Uruguay 2005    only    -       Mar
> 27       2:00   0
> # 02:00 local time, official time in Uruguay will be at GMT -2.
> Rule   Uruguay 2005    only    -       Oct      9       2:00   1:00    S
> Rule   Uruguay 2006    only    -       Mar     12       2:00   0       -
> +# From Jesper Norgaard Welen (2006-09-06):
> +#
> http://www.presidencia.gub.uy/_web/decretos/2006/09/CM%20210_08%2006%202006_00001.PDF
> +Rule   Uruguay 2006    max     -       Oct     Sun>=1   2:00   1:00    S
> +Rule   Uruguay 2007    max     -       Mar     Sun>=8   2:00   0       -
> # Zone NAME            GMTOFF  RULES   FORMAT  [UNTIL]
> Zone America/Montevideo        -3:44:44 -      LMT     1898 Jun 28
>                         -3:44:44 -      MMT     1920 May  1     #
> Montevideo MT
>
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