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[PATCH 1/2] Improve use of non-ASCII symbols in commentary
by Paul Eggert Feb. 16, 2018

Feb. 16, 2018

From: Paul Eggert <eggert(a)Penguin.CS.UCLA.EDU> Go back to using °, ±, etc. in commentary. This was prompted by my recent minor cleanup change of “34°” to “34 degrees” for Uruguay commentary. As it happens, this cleanup wasn't really needed for XEmacs, and it's annoying to have to use longwinded workarounds for common symbols. * Makefile (UNUSUAL_OK_CHARSET): New macro. (OK_CHAR): Use it. (check_character_set): Check Makefile seperately, since its UNUSUAL_OK_CHARSET can be a non-SAFE_LINE now. * NEWS: Mention this. --- Makefile | 22 +++++++++++++++------- NEWS | 6 +++++- asia | 11 +++++------ australasia | 4 ++-- backzone | 6 +++--- europe | 14 +++++++------- northamerica | 5 ++--- southamerica | 2 +- zone1970.tab | 2 +- 9 files changed, 41 insertions(+), 31 deletions(-) diff --git a/Makefile b/Makefile index 47acbbd..fc15c3e 100644 --- a/Makefile +++ b/Makefile @@ -408,13 +408,19 @@ SAFE_CHARSET3= 'abcdefghijklmnopqrstuvwxyz{|}~' SAFE_CHARSET= $(SAFE_CHARSET1)$(SAFE_CHARSET2)$(SAFE_CHARSET3) SAFE_CHAR= '[]'$(SAFE_CHARSET)'-]' +# Non-ASCII non-letters that OK_CHAR allows, as these characters are +# useful in commentary. XEmacs 21.5.34 displays them correctly, +# presumably because they are Latin-1. +UNUSUAL_OK_CHARSET= °±½¾× + # OK_CHAR matches any character allowed in the distributed files. -# This is the same as SAFE_CHAR, except that multibyte letters are -# also allowed so that commentary can contain people's names and quote -# non-English sources. For non-letters the sources are limited to -# ASCII renderings for the convenience of maintainers whose text editors -# mishandle UTF-8 by default (e.g., XEmacs 21.4.22). -OK_CHAR= '[][:alpha:]'$(SAFE_CHARSET)'-]' +# This is the same as SAFE_CHAR, except that UNUSUAL_OK_CHARSET and +# multibyte letters are also allowed so that commentary can contain a +# few safe symbols and people's names and can quote non-English sources. +# Other non-letters are limited to ASCII renderings for the +# convenience of maintainers using XEmacs 21.5.34, which by default +# mishandles Unicode characters U+0100 and greater. +OK_CHAR= '[][:alpha:]$(UNUSUAL_OK_CHARSET)'$(SAFE_CHARSET)'-]' # SAFE_LINE matches a line of safe characters. # SAFE_SHARP_LINE is similar, except any OK character can follow '#'; @@ -689,8 +695,10 @@ check_character_set: $(ENCHILADA) sharp='#' && \ ! grep -Env $(SAFE_LINE) $(MANS) date.1 $(MANTXTS) \ $(MISC) $(SOURCES) $(WEB_PAGES) \ - CONTRIBUTING LICENSE Makefile README \ + CONTRIBUTING LICENSE README \ version tzdata.zi && \ + ! grep -Env $(SAFE_LINE)'|^UNUSUAL_OK_CHARSET='$(OK_CHAR)'*$$' \ + Makefile && \ ! grep -Env $(SAFE_SHARP_LINE) $(TDATA_TO_CHECK) backzone \ leapseconds yearistype.sh zone.tab && \ ! grep -Env $(OK_LINE) $(ENCHILADA); \ diff --git a/NEWS b/NEWS index b83cce9..1e2cfdf 100644 --- a/NEWS +++ b/NEWS @@ -108,6 +108,10 @@ Unreleased, experimental changes with links to many relevant legal documents. (Thanks to Tim Parenti.) + Commentary now uses some non-ASCII characters with Unicode value + less than U+0100, as they can be useful and should work even with + older editors such as XEmacs. + Release 2018c - 2018-01-22 23:00:44 -0800 @@ -1009,7 +1013,7 @@ Release 2016b - 2016-03-12 17:30:14 -0800 Comments in zone tables have been improved. (Thanks to J William Piggott.) tzselect again limits its menu comments so that menus fit on a - 24x80 alphanumeric display. + 24×80 alphanumeric display. A new web page tz-how-to.html. (Thanks to Bill Seymour.) diff --git a/asia b/asia index 63d2fb0..5c2fc50 100644 --- a/asia +++ b/asia @@ -1478,8 +1478,7 @@ Rule Japan 1950 1951 - May Sat>=1 24:00 1:00 D # From Hideyuki Suzuki (1998-11-09): # 'Tokyo' usually stands for the former location of Tokyo Astronomical -# Observatory: 139 degrees 44' 40.90" E (9h 18m 58.727s), -# 35 degrees 39' 16.0" N. +# Observatory: 139° 44' 40.90" E (9h 18m 58.727s), 35° 39' 16.0" N. # This data is from 'Rika Nenpyou (Chronological Scientific Tables) 1996' # edited by National Astronomical Observatory of Japan.... # JST (Japan Standard Time) has been used since 1888-01-01 00:00 (JST). @@ -1487,10 +1486,10 @@ Rule Japan 1950 1951 - May Sat>=1 24:00 1:00 D # From Hideyuki Suzuki (1998-11-16): # The ordinance No. 51 (1886) established "standard time" in Japan, -# which stands for the time on 135 degrees E. +# which stands for the time on 135° E. # In the ordinance No. 167 (1895), "standard time" was renamed to "central # standard time". And the same ordinance also established "western standard -# time", which stands for the time on 120 degrees E.... But "western standard +# time", which stands for the time on 120° E.... But "western standard # time" was abolished in the ordinance No. 529 (1937). In the ordinance No. # 167, there is no mention regarding for what place western standard time is # standard.... @@ -3097,9 +3096,9 @@ Zone Asia/Tashkent 4:37:11 - LMT 1924 May 2 # and is the basis for the information below. # # The 1906 transition was effective July 1 and standardized Indochina to -# Phù Liễn Observatory, legally 104 deg. 17'17" east of Paris. +# Phù Liễn Observatory, legally 104° 17' 17" east of Paris. # It's unclear whether this meant legal Paris Mean Time (00:09:21) or -# the Paris Meridian (2 deg. 20'14.03" E); the former yields 07:06:30.1333... +# the Paris Meridian (2° 20' 14.03" E); the former yields 07:06:30.1333... # and the latter 07:06:29.333... so either way it rounds to 07:06:30, # which is used below even though the modern-day Phù Liễn Observatory # is closer to 07:06:31. Abbreviate Phù Liễn Mean Time as PLMT. diff --git a/australasia b/australasia index 4f96458..c7c0ea7 100644 --- a/australasia +++ b/australasia @@ -1610,7 +1610,7 @@ Zone Pacific/Wallis 12:15:20 - LMT 1901 # From Howie Phelps (1999-11-10), who talked to a Pitcairner via shortwave: # Betty Christian told me yesterday that their local time is the same as -# Pacific Standard Time. They used to be 1/2 hour different from us here in +# Pacific Standard Time. They used to be ½ hour different from us here in # Sacramento but it was changed a couple of years ago. @@ -1649,7 +1649,7 @@ Zone Pacific/Wallis 12:15:20 - LMT 1901 # 12 hours and 20 minutes ahead of GMT. When New Zealand adjusted its # standard time in 1940s, Tonga had the choice of subtracting from its # local time to come on the same standard time as New Zealand or of -# advancing its time to maintain the differential of 13 degrees +# advancing its time to maintain the differential of 13° # (approximately 50 minutes ahead of New Zealand time). # # Because His Majesty King Tāufaʻāhau Tupou IV, then Crown Prince diff --git a/backzone b/backzone index cc724aa..2071110 100644 --- a/backzone +++ b/backzone @@ -409,7 +409,7 @@ Zone Asia/Bahrain 3:22:20 - LMT 1920 # Manamah # From Paul Eggert (2014-08-21): # In tomorrow's The Hindu, Nitya Menon reports that India had two civil time # zones starting in 1884, one in Bombay and one in Calcutta, and that railways -# used a third time zone based on Madras time (80 deg. 18'30" E). Also, +# used a third time zone based on Madras time (80° 18' 30" E). Also, # in 1881 Bombay briefly switched to Madras time, but switched back. See: # http://www.thehindu.com/news/cities/chennai/madras-375-when-madras-clocked-… #Zone Asia/Chennai [not enough info to complete] @@ -532,7 +532,7 @@ Zone Europe/Belfast -0:23:40 - LMT 1880 Aug 2 # Data from Joseph S. Myers # https://mm.icann.org/pipermail/tz/2013-September/019883.html # References to be added -# LMT is for Town Church, St. Peter Port, 49 degrees 27'17"N 2 degrees 32'10"W +# LMT is for Town Church, St. Peter Port, 49° 27' 17" N, 2° 32' 10" W. Zone Europe/Guernsey -0:10:09 - LMT 1913 Jun 18 0:00 GB-Eire %s 1940 Jul 2 1:00 C-Eur CE%sT 1945 May 8 @@ -566,7 +566,7 @@ Zone Europe/Isle_of_Man -0:17:55 - LMT 1883 Mar 30 0:00s # Data from Joseph S. Myers # https://mm.icann.org/pipermail/tz/2013-September/019883.html # References to be added -# LMT is for Parish Church, St. Helier, 49 degrees 11'0.57"N 2 degrees 6'24.33"W +# LMT is for Parish Church, St. Helier, 49° 11' 0.57" N, 2° 6' 24.33" W. Zone Europe/Jersey -0:08:26 - LMT 1898 Jun 11 16:00u 0:00 GB-Eire %s 1940 Jul 2 1:00 C-Eur CE%sT 1945 May 8 diff --git a/europe b/europe index 8aab26e..6bbb49d 100644 --- a/europe +++ b/europe @@ -117,8 +117,8 @@ # along the towpath within a few yards of it.' # # I have a one inch to one mile map of London and my estimate of the stone's -# position is 51 degrees 28' 30" N, 0 degrees 18' 45" W. The longitude should -# be within about +-2". The Ordnance Survey grid reference is TQ172761. +# position is 51° 28' 30" N, 0° 18' 45" W. The longitude should +# be within about ±2". The Ordnance Survey grid reference is TQ172761. # # [This yields GMTOFF = -0:01:15 for London LMT in the 18th century.] @@ -158,7 +158,7 @@ # after-hours daylight in which to pursue his research. # In 1895 he presented a paper to the Wellington Philosophical Society # that proposed a two-hour daylight-saving shift. See: -# Hudson GV. On seasonal time-adjustment in countries south of lat. 30 deg. +# Hudson GV. On seasonal time-adjustment in countries south of lat. 30°. # Transactions and Proceedings of the New Zealand Institute. 1895;28:734 # http://rsnz.natlib.govt.nz/volume/rsnz_28/rsnz_28_00_006110.html # Although some interest was expressed in New Zealand, his proposal @@ -2594,13 +2594,13 @@ Zone Europe/Kaliningrad 1:22:00 - LMT 1893 Apr # From Vladimir Karpinsky (2014-07-08): # LMT in Moscow (before Jul 3, 1916) is 2:30:17, that was defined by Moscow -# Observatory (coordinates: 55 deg. 45'29.70", 37 deg. 34'05.30").... +# Observatory (coordinates: 55° 45' 29.70", 37° 34' 05.30").... # LMT in Moscow since Jul 3, 1916 is 2:31:01 as a result of new standard. # (The info is from the book by Byalokoz ... p. 18.) # The time in St. Petersburg as capital of Russia was defined by # Pulkov observatory, near St. Petersburg. In 1916 LMT Moscow # was synchronized with LMT St. Petersburg (+30 minutes), (Pulkov observatory -# coordinates: 59 deg. 46'18.70", 30 deg. 19'40.70") so 30 deg. 19'40.70" > +# coordinates: 59° 46' 18.70", 30° 19' 40.70") so 30° 19' 40.70" > # 2h01m18.7s = 2:01:19. LMT Moscow = LMT St.Petersburg + 30m 2:01:19 + 0:30 = # 2:31:19 ... # @@ -3429,7 +3429,7 @@ Zone Atlantic/Canary -1:01:36 - LMT 1922 Mar # Las Palmas de Gran C. # three degrees, or twelve minutes of time, to the west of the # meridian of the Observatory of Stockholm". The law is dated 1878-05-31. # -# The observatory at that time had the meridian 18 degrees 03' 30" +# The observatory at that time had the meridian 18° 03' 30" # eastern longitude = 01:12:14 in time. Less 12 minutes gives the # national standard time as 01:00:14 ahead of GMT.... # @@ -3533,7 +3533,7 @@ Zone Europe/Stockholm 1:12:12 - LMT 1879 Jan 1 # From Alois Treindl (2013-09-11): # The Federal regulations say # https://www.admin.ch/opc/de/classified-compilation/20071096/index.html -# ... the meridian for Bern mean time ... is 7 degrees 26' 22.50". +# ... the meridian for Bern mean time ... is 7° 26' 22.50". # Expressed in time, it is 0h29m45.5s. # From Pierre-Yves Berger (2013-09-11): diff --git a/northamerica b/northamerica index dabca97..f4e38f8 100644 --- a/northamerica +++ b/northamerica @@ -424,8 +424,7 @@ Zone America/North_Dakota/New_Salem -6:45:39 - LMT 1883 Nov 18 12:14:21 # ...according to the Census Bureau, the largest city is Beulah (although # it's commonly referred to as Beulah-Hazen, with Hazen being the next # largest city in Mercer County). Google Maps places Beulah's city hall -# at 47 degrees 15' 51" N, 101 degrees 46' 40" W, which yields an offset -# of 6h47'07". +# at 47° 15' 51" N, 101° 46' 40" W, which yields an offset of 6h47'07". Zone America/North_Dakota/Beulah -6:47:07 - LMT 1883 Nov 18 12:12:53 -7:00 US M%sT 2010 Nov 7 2:00 @@ -458,7 +457,7 @@ Zone America/Denver -6:59:56 - LMT 1883 Nov 18 12:00:04 # California, northern Idaho (Benewah, Bonner, Boundary, Clearwater, # Kootenai, Latah, Lewis, Nez Perce, and Shoshone counties, Idaho county # north of the Salmon River, and the towns of Burgdorf and Warren), -# Nevada (except West Wendover), Oregon (except the northern 3/4 of +# Nevada (except West Wendover), Oregon (except the northern ¾ of # Malheur county), and Washington # From Paul Eggert (2016-08-20): diff --git a/southamerica b/southamerica index d97343e..c6c461c 100644 --- a/southamerica +++ b/southamerica @@ -1694,7 +1694,7 @@ Link America/Port_of_Spain America/Tortola # Virgin Islands (UK) # auspices of the National Institute for the Prediction of Time. It is unclear # exactly what offset was used during this period, though Ley No. 7200 of # 1920-04-23 used the Observatory of the National Meteorological Institute in -# Montevideo (S 34 deg. 54'33", W 056 deg. 12'45") as its reference meridian, +# Montevideo (34° 54' 33" S, 56° 12' 45" W) as its reference meridian, # retarding legal time by 15 minutes 9 seconds from 1920-04-30 24:00, # resulting in UT-04. Assume the corresponding LMT of UT-03:44:51 (given on # page 725 of the Proceedings of the Second Pan-American Scientific Congress, diff --git a/zone1970.tab b/zone1970.tab index a3b6b04..2d90ed7 100644 --- a/zone1970.tab +++ b/zone1970.tab @@ -12,7 +12,7 @@ # of ISO 3166 2-character country codes. See the file 'iso3166.tab'. # 2. Latitude and longitude of the zone's principal location # in ISO 6709 sign-degrees-minutes-seconds format, -# either +-DDMM+-DDDMM or +-DDMMSS+-DDDMMSS, +# either ±DDMM±DDDMM or ±DDMMSS±DDDMMSS, # first latitude (+ is north), then longitude (+ is east). # 3. Zone name used in value of TZ environment variable. # Please see the theory.html file for how zone names are chosen. -- 2.14.3

2 3

models for timezones
by scs＠eskimo.com Feb. 14, 2018

Feb. 14, 2018

It gets mentioned here often enough, but there's another significant aspect of the tz database which I'm not sure is always sufficiently appreciated, and that's how significantly it extends on the old V7/SysV/Posix model of time zones. In that old model, a time zone has one offset from Greenwich/UTC, and maybe a second offset on top of that to realize "daylight saving time", and one set of rules for deciding when to transition to and from DST. (Once upon a time, that set of rules might have been limited to the pre-1987 rules for the United States, and it might have been hard-compiled into C code. With the advent of the Posix TZ environment variable definition it's at least a little bit more flexible.) But of course (and since the beginning) the tz database has expanded on that model in at least two different ways: 1. It's not limited to one "standard" and perhaps one "daylight" time per year; there can be almost arbitrarily many offsets and arbitrarily many transition dates between them. 2. Everything -- the "base" offset (not that this is even a meaningful concept any more), the alternate offsets, and the transition dates between them can vary over time. And of course the reasons for doing this were that both changes were necessary in order to accommodate the real world; the old SysV/Posix model simply couldn't cope. But this means that there's a significantly imperfect match between the tz database and any programming language or time-handling library that has any of these notions: * A timezone is primarily defined by its base offset from UTC. * It's an additional property of a timezone whether it observes DST or not. * If DST applies to a timezone, it's defined by an additional offset and a single set of rules defining when it applies. * DST always involves a positive offset from the base offset. You *might* be able to get away with a tricky and/or imperfect mapping between the tz database and a scheme that has some of those notions -- for example, the tz reference code successfully implements the C/Posix API, isdst flag and all -- but it's bound to have warts or imperfections. Everything I've said here is, I imagine, familiar and unsurprising to any regular reader of this list, but it probably bears a bit more discussion in the Theory file. I was going to suggest adding these two new bullets under "Extensions to POSIX": * The TZ database allows for considerably more variation in time per year beyond the familiar "standard" and "daylight savings" times. A time zone can have any number of variations per year, and they may have arbitrary designations, not limited to "standard" and "daylight". * The parameters defining a time zone can vary over time, reflecting the fact that this happens in the real world all the time, as legislatures continually redefine them. Whether and when a zone observes DST (or other variants), and even the zone's notional "base offset" from UTC, are variable. (Therefore it doesn't even really make sense to talk about a zone's "base offset", since it's not necessarily a single number.) But that's in the "Time and date functions" section, and easy to overlook. So maybe these words belong as a paragraph higher up, perhaps even in the initial "Scope of the tz database" section: Because the database's scope encompasses real-world timezones which have wide-ranging complexity and are always evolving, the model for describing time zones allows for considerably more variation in time per year beyond the familiar "standard" and "daylight savings" times. A time zone can have any number of variations per year, and they may have arbitrary designations, not limited to "standard" and "daylight". Furthermore, the parameters defining a time zone can vary over time. Whether and when a zone observes DST (or other variants), and even the zone's notional "base offset" from UTC, are variable. (Therefore it doesn't even really make sense to talk about a zone's "base offset", since it is not necessarily a single number.)

3 3

Recommendations for stable list of timezone ids
by Tobias Lindaaker Feb. 14, 2018

Feb. 14, 2018

I am trying to compile a flat list of all tzids in the Time Zone Database in a way such that the position of a tzid remains the same in the list even in the face of future changes to the Time Zone Database. I would like to know if anyone could provide me with some insight into how (a prefix of) such a list could be generated from any version of the Time Zone Database. Or would this be something I would have to maintain myself from release to release of the Time Zone Database? The requirements I would have for generating this list would be that given two releases of the Time Zone Database, X and Y. If X is released before Y, then the list generated from X must be a prefix of the list generated from Y (and vice versa: if Y is released before X, the list generated from Y must be a prefix of the list generated from X). A simple alphabetical ordering is obviously not going to work, since for example the addition of America/Punta_Arenas in 2017a would end up before many of the tzids that existed in versions prior. Since I don't require this to work for all historical releases, my first thought was to start from a fairly recent release (tzdata2013h) and verify that I got the same order when sorting the timezones based on their earliest rule. However the removal of tzids (such as Canada/East-Saskatchewan in tzdata2017c) made this impossible, since any removal makes it impossible to ensure that prior versions are strict prefixes. It now seems as if I would have to maintain this list myself, tracking each release of the Time Zone Database and ensure that any tzids added to the Time Zone Database are appended to my list in release order. If possible I would very much prefer to avoid this, since it requires me to release updates of my software to track the releases of the Time Zone Database, I would much rather like it if my software could rely on the Time Zone Database available from the system where it was running. Finally some background on why (I think) I need to generate this type of list of tzids: I am improving the support for storing timestamp values in a database management system (Neo4j), and would like to avoid having to store the timezone component of zoned timestamps as a (variable length) text component, but rather store it as a fixed size integer offset into a table of tzids. Thus I need such a stable list of tzids. I have tried searching the archives of this mailing list for similar questions before posting, but have not been able to find such an entry. The closest I found were a few questions on how to translate the tzids to localized names. Since I did not read through the entire archives, but only did a search, I apologise in advance if this has been asked and solved before, and hope that you will be able to direct my attention to that thread. Thank you, Tobias

8 15

Inappropriate project direction
by Stephen Colebourne Feb. 12, 2018

Feb. 12, 2018

In the last few years, the following changes have been made to the tzdb project. Each of these - added no value - had a cost that far exceeded the benefits - should not have happened 1) Removal of Zone definitions from many countries. While the Zone definitions may have been the same across different countries, it was never appropriate to merge the time-zones of multiple different countries (backzone being the result). - the change caused LMT values to be lost - downstream consumers had to change logic wrt the meaning of backzone - it was culturally insensitive to not provide a primary Zone entry for some countries 2) Removal of textual short zone names. While these names may well have been invented in some cases, the had often become de facto standards - end-users complained about the loss of textual names - downstream consumers had to change logic to handle numeric-style identifiers 3) Move to a niche archive format The main archive format was changed from the well-known and widely supported gz to the niche lz format. There was and is no justification for using a niche format on a project as important as this one. - downstream consumers need to find and use the niche format - Windows does not have proper support for the niche format 4) Negative SAVE values Despite being a known fact in tzdb since 2005, and despite being warned not to in advance, a decision to re-interpret the meaning of Ireland DST was pushed through. - downstream consumers broke - the interaction with CLDR is incompatible with negative DST - the change has no impact on actual times - even if someone thought it was broken, there are no benefits to making the change 5) Fractional seconds A desire to fix subsecond data from over 50 years ago. - downstream consumers will break - the number of people who care is vanishingly small Were recent discussions a one-off, I might be prepared to let things lie, but as can be seen, there is a pattern here. Not one of these changes has added value to the project. Not one of them has been necessary to the primary mission of recording what governments are doing to their clocks now, nor even in the last 40 years. Worse, the majority are driven by a notion that getting the data "pure" trumps all problems reported by downstream consumers. It is long past time to accept that tzdb needs to focus on the primary mission - recording current government changes in a stable, backwards compatible manner. Tinkering needs to stop. Stephen

10 15

EP vote on EU DST; afternoon gloom in Scotland
by Paul Eggert Feb. 11, 2018

Feb. 11, 2018

On Thursday, the European Parliament voted 384-152 to pass a nonbinding resolution calling for the European Commission to re-evaluate the current system of daylight saving time in Europe. An article about this and how it's entangled with European politics can be found here: Yeginsu C. Daylight saving time: what's it good for? European lawmakers ask. New York Times. 2018-02-09. https://www.nytimes.com/2018/02/09/world/europe/europe-daylight-saving.html My favorite quote is about the UK Daylight Saving Bill 2010-12. Yeginsu writes: "That bill was met with fierce resistance in places like Scotland, where residents argued that they liked the afternoon gloom just fine."

2 1

License of lzip, lzlib and pdlzip
by Antonio Diaz Diaz Feb. 11, 2018

Feb. 11, 2018

Bryan Smith wrote: > There is still a heavy copyleft (e.g., GPL) v. non-copyleft FLOSS > debate that rages on, with various people putting various values -- > from nothing to everything -- on that. lzip -- or more problematic, > it's lzlib -- is GPLv2 -- not even LGPL -- which has some asterisks > for commercial developers. I don't know the state of public domain > lzip (pdlzip), but it seems to be good enough for any decompression > (and most general compression). Thanks for your comments. I'll just add a clarification about lzip licensing. Lzip itself is GPL version 2 or later. Lzlib was also GPLv2+, but a year ago (in version 1.9) the license was changed to 2-clause BSD as you can see in lzlib's homepage[1]. There is also another BSD licensed library (libarchive) able to (de)compress lzip files and lzip-compressed tar archives. Pdlzip has a 2-clause BSD license[2]. It is maintained and fully compatible with the lzip format for both compression and decompression. [1] http://www.nongnu.org/lzip/lzlib.html [2] http://www.nongnu.org/lzip/pdlzip.html Best regards, Antonio.

1 0

Fractional seconds in zic input
by Paul Eggert Feb. 10, 2018

Feb. 10, 2018

For many years I've chafed at tzdata's lack of support for fractional seconds. We have good evidence of well-established standard-time UT offsets that were not multiples of one second; for example, the Netherlands before 1937. These can't be recorded in tzdata except as comments. Ideally tzcode would support fractional-second times and UT offsets all the way down the chain. This would mean changes to the tz binary format and to the runtime API, though, which is not something we'd do lightly, if ever. However, it's easy to change the zic spec to allow fractional seconds, and to change zic to accept and ignore the fractions, so that fractional seconds can be documented more formally in the data; this could well be useful to applications other than tzcode. Proposed patch attached, hairy sscanf format and all. This patch does not actually change the data, as we'll need time, and/or a procedure to automatically generate data compatible with zic 2018c and earlier.

17 51

tzdata source compatibility
by christos＠zoulas.com Feb. 7, 2018

Feb. 7, 2018

Hi, Here's my 5 cents to the tzdb compatibility discussion: - Things need to move forward; half-measures like "functional comments" end up hurting in the long term and create unpredictable behavior. - There are other users of the tzdata "source" so compatibility needs to be maintained for "some time". - On the other hand, we can't be held hostage forever; people who write parsers, should be able to maintain the code. Straw man proposal: 1. Create a version ChangeLog with tzdb; it should be simple: - a version number (for reference) - the release date (to guide expiration) - an explanation to what changed in the format (for parser writers) 2. Maintain two copies of the source; the current one, and the previous version in a "compat" subdirectory. Expire "compat" a year after the release of the next version. I hope this is helpful, christos

5 6

New open-source zoneinfo compiler
by Kerry Shetline Feb. 5, 2018

Feb. 5, 2018

Hi, In case this might be of use to others, I’ve posted a new project on GitHub, https://github.com/kshetline/compact-time-zone-generator <https://github.com/kshetline/compact-time-zone-generator>. This is a parser and compiler written in Java that produces output primarily meant to be used with web apps. The project also includes an Angular demo app which consumes this format of compiled time zone data. The README for the project explains more, and provides some demo links, which might help decide if this is a project that might be useful to share on the discussion list. -Kerry

2 1

[PROPOSED] Fix 0.5 s bug for Jakarta in 1923
by Paul Eggert Feb. 5, 2018

Feb. 5, 2018

* ziguard.awk: Fix bug for Asia/Jakarta: the 1923-12-31 transition was off by 0.5 s when fractional seconds were enabled. --- ziguard.awk | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/ziguard.awk b/ziguard.awk index 795b4ef..70376b7 100644 --- a/ziguard.awk +++ b/ziguard.awk @@ -38,6 +38,8 @@ BEGIN { frac["7:07:12"] = "7:07:12.5" # Asia/Jakarta before 1923 frac["7:36:42"] = "7:36:41.7" # Asia/Hong_Kong before 1904 frac["8:05:43"] = "8:05:43.2" # Asia/Shanghai before 1901 + + fract["23:47:12"] = "23:47:12.5" # Asia/Jakarta 1923-12-31 transition } /^Zone/ { zone = $2 } @@ -61,7 +63,7 @@ outfile != "main.zi" { } } - # Add or remove fractional seconds as needed. + # Add or remove fractional seconds as needed in UT offsets. f = $1 == "Zone" ? 3 : 1 for (rounded in frac) { original = frac[rounded] @@ -69,6 +71,13 @@ outfile != "main.zi" { $f = vanguard ? original : rounded } } + # Likewise for transition times. + for (rounded in fract) { + original = fract[rounded] + if ($(f + 6) == rounded || $(f + 6) == original) { + $(f + 6) = vanguard ? original : rounded + } + } } # If a Link line is followed by a Zone line for the same data, comment -- 2.14.3

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