In which of four zones should lastThu 24:00 be used
Responses on the mailing list indicate that use of 24:00 in timezone source files is the way to go where appropriate. The question now is: where is where? There are four places currently using a "lastFri 0:00" rule for the start of DST now and into the future: Script started on Tue May 05 09:43:53 2009 lecserver$ grep -i max.*lastfri.*0:00.*1:00 * africa:Rule Egypt 1995 max - Apr lastFri 0:00s 1:00 S asia:Rule Jordan 2002 max - Mar lastFri 0:00s 1:00 S asia:Rule Palestine 2009 max - Mar lastFri 0:00 1:00 S asia:Rule Syria 2009 max - Mar lastFri 0:00 1:00 S lecserver$ exit script done on Tue May 05 09:44:14 2009 We've seen a report that Jordan should really be "...Mar lastThu 24:00..." What of the other three areas? (Alas, Egypt is the only one of the three where a look at old newspapers might help.) --ado
"Olson, Arthur David (NIH/NCI) [E]" <olsona@dc37a.nci.nih.gov> writes:
Responses on the mailing list indicate that use of 24:00 in timezone source files is the way to go where appropriate. The question now is: where is where?
I would guess that all four locations (Egypt, Jordan, Palestine, and Syria) are inspired by the same mental ruleset, and if we have good evidence that one should be lastThu 24:00, then we should do the same with the other four.
Paul Eggert writes:
I would guess that all four locations (Egypt, Jordan, Palestine, and Syria) are inspired by the same mental ruleset, and if we have good evidence that one should be lastThu 24:00, then we should do the same with the other four.
I disagree that interpreting mental rulesets is a good way forward. Rather I would recommend to check each occurence where it actually matters and create the rules based on that. For Egypt the only difference of the two rules for the period 1995-2009 occurs in 1998 and 2009, concerning Friday 1.st. of May 1998 and Friday 1.st. of May 2009. We already saw that in 2009 the change took place on the 24.th. of April so did not follow Last Thursday of April at 24:00. I have no information from 1998, but I doubt that Last Thursday of April would be correct in 1998. Jordan is really the inspiration for these rule changes and here it must be correct. In Palestine there are no rules further back than 2008 that are relevant for this ruleset, and for 2008 and 2009 apparently the rule is Last Thursday of March at 24:00, although none of them have 1.st. of April being a Friday so we won't know yet. For Syria we could put the rule for years 2007 and 2009, but these years were non-critical since either rule would work. And since we already had an exception in 2008 (First Friday of April) I think it is hard to argue they go by a rule or a mindset. - Jesper Nørgaard Welen
participants (3)
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Jesper Nørgaard -
Olson, Arthur David (NIH/NCI) [E] -
Paul Eggert