[tz] [PROPOSED PATCH] Switch from 'zzz' to '-00' for uninhabited abbr
Paul Eggert
eggert at cs.ucla.edu
Sun May 29 21:39:51 UTC 2016
* NEWS, Theory, tz-how-to.html: Document this.
* antarctica (Antarctica/Casey, Antarctica/Davis)
(Antarctica/Mawson, Indian/Kerguelen, Antarctica/DumontDUrville):
(Antarctica/Syowa, Antarctica/Troll, Antarctica/Vostok)
(Antarctica/Rothera):
* australasia (Antarctica/Macquarie):
* backzone (Antarctica/McMurdo):
* northamerica (America/Pangnirtung, America/Iqaluit)
(America/Resolute, America/Rankin_Inlet, America/Cambridge_Bay)
(America/Yellowknife, America/Inuvik):
* southamerica (Antarctica/Palmer):
Use '-00', not 'zzz', to abbreviate UT in uninhabited locations.
---
NEWS | 7 +++++++
Theory | 7 ++++---
antarctica | 24 ++++++++++++------------
australasia | 4 ++--
backzone | 2 +-
northamerica | 14 +++++++-------
southamerica | 2 +-
tz-how-to.html | 16 ++++++++++------
8 files changed, 44 insertions(+), 32 deletions(-)
diff --git a/NEWS b/NEWS
index b5fb182..54a520d 100644
--- a/NEWS
+++ b/NEWS
@@ -11,6 +11,13 @@ Unreleased, experimental changes
Changes affecting past time stamps
+ Locations while uninhabited now use '-00', not 'zzz', as a
+ placeholder time zone abbreviation. This is inspired by Internet
+ RFC 3339 and is more consistent with numeric time zone
+ abbreviations already used elsewhere. The change affects several
+ arctic and antarctic locations, e.g., America/Cambridge_Bay before
+ 1920 and Antarctica/Troll before 2005.
+
Asia/Baku's 1992-09-27 transition from +04 (DST) to +04 (non-DST) was
at 03:00, not 23:00 the previous day. (Thanks to Michael Deckers.)
diff --git a/Theory b/Theory
index 6bed91f..60678fe 100644
--- a/Theory
+++ b/Theory
@@ -227,9 +227,10 @@ in decreasing order of importance:
name identifying each zone and append 'T', 'ST', etc.
as before; e.g. 'VLAST' for VLAdivostok Summer Time.
- Use UT (with time zone abbreviation 'zzz') for locations while
- uninhabited. The 'zzz' mnemonic is that these locations are,
- in some sense, asleep.
+ Use UT (with time zone abbreviation '-00') for locations while
+ uninhabited. The leading '-' is a flag that the time
+ zone is in some sense undefined; this notation is
+ derived from Internet RFC 3339.
Application writers should note that these abbreviations are ambiguous
in practice: e.g. 'CST' has a different meaning in China than
diff --git a/antarctica b/antarctica
index 2af088f..a537832 100644
--- a/antarctica
+++ b/antarctica
@@ -13,7 +13,7 @@
#
# Except for the French entries,
# I made up all time zone abbreviations mentioned here; corrections welcome!
-# FORMAT is 'zzz' and GMTOFF is 0 for locations while uninhabited.
+# FORMAT is '-00' and GMTOFF is 0 for locations while uninhabited.
# Argentina - year-round bases
# Belgrano II, Confin Coast, -770227-0343737, since 1972-02-05
@@ -67,22 +67,22 @@
# http://www.timeanddate.com/news/time/antartica-time-changes-2010.html
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-Zone Antarctica/Casey 0 - zzz 1969
+Zone Antarctica/Casey 0 - -00 1969
8:00 - AWST 2009 Oct 18 2:00
# Australian Western Std Time
11:00 - CAST 2010 Mar 5 2:00 # Casey Time
8:00 - AWST 2011 Oct 28 2:00
11:00 - CAST 2012 Feb 21 17:00u
8:00 - AWST
-Zone Antarctica/Davis 0 - zzz 1957 Jan 13
+Zone Antarctica/Davis 0 - -00 1957 Jan 13
7:00 - DAVT 1964 Nov # Davis Time
- 0 - zzz 1969 Feb
+ 0 - -00 1969 Feb
7:00 - DAVT 2009 Oct 18 2:00
5:00 - DAVT 2010 Mar 10 20:00u
7:00 - DAVT 2011 Oct 28 2:00
5:00 - DAVT 2012 Feb 21 20:00u
7:00 - DAVT
-Zone Antarctica/Mawson 0 - zzz 1954 Feb 13
+Zone Antarctica/Mawson 0 - -00 1954 Feb 13
6:00 - MAWT 2009 Oct 18 2:00 # Mawson Time
5:00 - MAWT
# References:
@@ -137,7 +137,7 @@ Zone Antarctica/Mawson 0 - zzz 1954 Feb 13
# fishing stations operated variously 1819/1931
#
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-Zone Indian/Kerguelen 0 - zzz 1950 # Port-aux-Français
+Zone Indian/Kerguelen 0 - -00 1950 # Port-aux-Français
5:00 - TFT # ISO code TF Time
#
# year-round base in the main continent
@@ -148,9 +148,9 @@ Zone Indian/Kerguelen 0 - zzz 1950 # Port-aux-Français
# It was destroyed by fire on 1952-01-14.
#
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-Zone Antarctica/DumontDUrville 0 - zzz 1947
+Zone Antarctica/DumontDUrville 0 - -00 1947
10:00 - PMT 1952 Jan 14 # Port-Martin Time
- 0 - zzz 1956 Nov
+ 0 - -00 1956 Nov
10:00 - DDUT # Dumont-d'Urville Time
# France & Italy - year-round base
@@ -176,7 +176,7 @@ Zone Antarctica/DumontDUrville 0 - zzz 1947
# was established on 1957-01-29. Since Syowa station is still the main
# station of Japan, it's appropriate for the principal location.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-Zone Antarctica/Syowa 0 - zzz 1957 Jan 29
+Zone Antarctica/Syowa 0 - -00 1957 Jan 29
3:00 - SYOT # Syowa Time
# See:
# NIPR Antarctic Research Activities (1999-08-17)
@@ -226,7 +226,7 @@ Rule Troll 2005 max - Mar lastSun 1:00u 2:00 CEST
# Remove the following line when uncommenting the above '#Rule' lines.
Rule Troll 2004 max - Oct lastSun 1:00u 0:00 UTC
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-Zone Antarctica/Troll 0 - zzz 2005 Feb 12
+Zone Antarctica/Troll 0 - -00 2005 Feb 12
0:00 Troll %s
# Poland - year-round base
@@ -267,7 +267,7 @@ Zone Antarctica/Troll 0 - zzz 2005 Feb 12
# happened to be during their visit. So we still don't really know what time
# it is at Vostok. But we'll guess UTC+6.
#
-Zone Antarctica/Vostok 0 - zzz 1957 Dec 16
+Zone Antarctica/Vostok 0 - -00 1957 Dec 16
6:00 - VOST # Vostok time
# S Africa - year-round bases
@@ -300,7 +300,7 @@ Zone Antarctica/Vostok 0 - zzz 1957 Dec 16
# <http://webexhibits.org/daylightsaving/g.html> says Rothera is -03 all year.
#
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-Zone Antarctica/Rothera 0 - zzz 1976 Dec 1
+Zone Antarctica/Rothera 0 - -00 1976 Dec 1
-3:00 - ROTT # Rothera time
# Uruguay - year round base
diff --git a/australasia b/australasia
index 55f44cf..0b33f67 100644
--- a/australasia
+++ b/australasia
@@ -243,11 +243,11 @@ Zone Australia/Lord_Howe 10:36:20 - LMT 1895 Feb
# will produce a binary file with an [A]EST-type as the first 32-bit type;
# this is required for correct handling of times before 1916 by
# pre-2013 versions of localtime.
-Zone Antarctica/Macquarie 0 - zzz 1899 Nov
+Zone Antarctica/Macquarie 0 - -00 1899 Nov
10:00 - AEST 1916 Oct 1 2:00
10:00 1:00 AEDT 1917 Feb
10:00 Aus AE%sT 1919 Apr 1 0:00s
- 0 - zzz 1948 Mar 25
+ 0 - -00 1948 Mar 25
10:00 Aus AE%sT 1967
10:00 AT AE%sT 2010 Apr 4 3:00
11:00 - MIST # Macquarie I Standard Time
diff --git a/backzone b/backzone
index 296eca8..13dc8d4 100644
--- a/backzone
+++ b/backzone
@@ -395,7 +395,7 @@ Zone America/Tortola -4:18:28 - LMT 1911 Jul # Road Town
-4:00 - AST
# McMurdo, Ross Island, since 1955-12
-Zone Antarctica/McMurdo 0 - zzz 1956
+Zone Antarctica/McMurdo 0 - -00 1956
12:00 NZ NZ%sT
Link Antarctica/McMurdo Antarctica/South_Pole
diff --git a/northamerica b/northamerica
index 1d7395c..6256f97 100644
--- a/northamerica
+++ b/northamerica
@@ -2191,39 +2191,39 @@ Rule NT_YK 1980 2006 - Oct lastSun 2:00 0 S
Rule NT_YK 1987 2006 - Apr Sun>=1 2:00 1:00 D
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# aka Panniqtuuq
-Zone America/Pangnirtung 0 - zzz 1921 # trading post est.
+Zone America/Pangnirtung 0 - -00 1921 # trading post est.
-4:00 NT_YK A%sT 1995 Apr Sun>=1 2:00
-5:00 Canada E%sT 1999 Oct 31 2:00
-6:00 Canada C%sT 2000 Oct 29 2:00
-5:00 Canada E%sT
# formerly Frobisher Bay
-Zone America/Iqaluit 0 - zzz 1942 Aug # Frobisher Bay est.
+Zone America/Iqaluit 0 - -00 1942 Aug # Frobisher Bay est.
-5:00 NT_YK E%sT 1999 Oct 31 2:00
-6:00 Canada C%sT 2000 Oct 29 2:00
-5:00 Canada E%sT
# aka Qausuittuq
-Zone America/Resolute 0 - zzz 1947 Aug 31 # Resolute founded
+Zone America/Resolute 0 - -00 1947 Aug 31 # Resolute founded
-6:00 NT_YK C%sT 2000 Oct 29 2:00
-5:00 - EST 2001 Apr 1 3:00
-6:00 Canada C%sT 2006 Oct 29 2:00
-5:00 - EST 2007 Mar 11 3:00
-6:00 Canada C%sT
# aka Kangiqiniq
-Zone America/Rankin_Inlet 0 - zzz 1957 # Rankin Inlet founded
+Zone America/Rankin_Inlet 0 - -00 1957 # Rankin Inlet founded
-6:00 NT_YK C%sT 2000 Oct 29 2:00
-5:00 - EST 2001 Apr 1 3:00
-6:00 Canada C%sT
# aka Iqaluktuuttiaq
-Zone America/Cambridge_Bay 0 - zzz 1920 # trading post est.?
+Zone America/Cambridge_Bay 0 - -00 1920 # trading post est.?
-7:00 NT_YK M%sT 1999 Oct 31 2:00
-6:00 Canada C%sT 2000 Oct 29 2:00
-5:00 - EST 2000 Nov 5 0:00
-6:00 - CST 2001 Apr 1 3:00
-7:00 Canada M%sT
-Zone America/Yellowknife 0 - zzz 1935 # Yellowknife founded?
+Zone America/Yellowknife 0 - -00 1935 # Yellowknife founded?
-7:00 NT_YK M%sT 1980
-7:00 Canada M%sT
-Zone America/Inuvik 0 - zzz 1953 # Inuvik founded
+Zone America/Inuvik 0 - -00 1953 # Inuvik founded
-8:00 NT_YK P%sT 1979 Apr lastSun 2:00
-7:00 NT_YK M%sT 1980
-7:00 Canada M%sT
diff --git a/southamerica b/southamerica
index fb437b2..1c38f63 100644
--- a/southamerica
+++ b/southamerica
@@ -1309,7 +1309,7 @@ Zone Pacific/Easter -7:17:28 - LMT 1890
# Palmer used to be supplied from Argentina.
#
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-Zone Antarctica/Palmer 0 - zzz 1965
+Zone Antarctica/Palmer 0 - -00 1965
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1982 May
-4:00 Chile CL%sT
diff --git a/tz-how-to.html b/tz-how-to.html
index 3fa7602..f0fedc5 100644
--- a/tz-how-to.html
+++ b/tz-how-to.html
@@ -466,13 +466,11 @@ offset, so the wall clock time during this period was GMT −
10:30 + 1:00 = GMT − 9:30.</p>
<p>The <code>FORMAT</code> column specifies the usual abbreviation of
-the time zone name. It can have one of four forms:</p>
+the time zone name. It can have one of three forms:</p>
<ul>
-<li>the string, “<code>zzz</code>,” which is a kind of
-null value (don’t ask)</li>
-
-<li>a single alphabetic string other than “<code>zzz</code>,”
+<li>a string of three or more characters that are either ASCII alphanumerics,
+“<code>+</code>”, or “<code>-</code>”,
in which case that’s the abbreviation</li>
<li>a pair of strings separated by a slash
@@ -513,7 +511,7 @@ a <code>SAVE</code> of zero.
</ul>
-<p>And two last things about the <code>FORMAT</code> column:</p>
+<p>And three last things about the <code>FORMAT</code> column:</p>
<ul>
<li>The <a href="https://en.wikipedia.org/wiki/Tz_database">tz
@@ -535,6 +533,12 @@ the abbreviations. They are intended to be the values returned through the
<a href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/strftime.html"><code>strftime</code></a>
function in the
<a href="http://www.chemie.fu-berlin.de/chemnet/use/info/libc/libc_19.html#SEC324">“C” locale</a>.
+
+<li>If there is no generally-accepted abbreviation for a time zone,
+a numeric offset is used instead, e.g., <code>+07</code> for 7 hours
+ahead of Greenwich. By convention, <code>-00</code> stands for an
+zone while uninhabited, where the offset is zero but in some sense
+the true offset is undefined.
</ul>
<p>As a final example, here’s the complete history for Hawaii:</p>
--
2.5.5
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