It's wise here to look at the IANA tz program, which is pretty comprehensive and maintained fairly scrupulously. See https://www.iana.org/time-zones . Hint: do NOT waste your time with the lz 'Complete set'.
Wise but also maddening, as the rules are baroque beyond belief. As an amusing aside, the documentation is complex and the comments make hilarious reading, as does the 2011 Astrolabe lawsuit (Mentioned here: https://en.wikipedia.org/wiki/Tz_database but as I recall, the details were quite weird) A few of years ago I wrote a Perl program to translate the tz rules into to a long but simple array of zones, transition times, offsets and daylight saving adjustments, and it nearly broke me. Good luck! My 2c, Jo. On Thu, 27 Dec 2018 at 21:26, Anssi Seppälä <[email protected]> wrote: > Yes indeed. Any system would be helpful because more difficulties are to > come: EU is planning to stop the day-light-saving-time and let the member > countries individually select to which time zone the want to stay. Not to > mention Brexit were Brittons surely do their own decision. > > Anssi > > -----Alkuperäinen viesti----- > Lähettäjä: Programming <[email protected]> > Puolesta Raul Miller > Lähetetty: Wednesday, 26 December 2018 21.44 > Vastaanottaja: Programming forum <[email protected]> > Aihe: [Jprogramming] time zones > > I ran into a situation today, where I need to handle time zones in J. > > After poking around a bit, I found > > > https://code.jsoftware.com/wiki/User:Ric_Sherlock/Extend_Dates_Project/DatesAdd_Script > > and > > http://www.jsoftware.com/pipermail/programming/2014-March/036357.html > > So, basically, here's my impression of where things are at: > > (1) time zones are an issue which people need to deal with relatively > often. > > (2) the details are arbitrary, vary from year to year and based on the > government in charge of the location in question. > > So: > > (3) There's almost always some sort of time zone database included with > every modern operating system. > > Currently, we've got informal partial support for time zones (only for > Windows - not for OSX, Linux, etc.). For the unix parts of the world, > probably https://man.openbsd.org/gettimeofday.2 or maybe as a > fallback: > https://www.gnu.org/software/libc/manual/html_node/Time-Zone-Functions.html > is the way to go... > > That's more work than my current project warrants - I'm just going to use > a hard coded constant for now, and maybe turn that into a prompted thing > later, if necessary. But I might come back to this issue at some point... > (and I expect other people will, also -- this is, after all, an issue that > people need to deal with relatively often). > > FYI, > > -- > Raul > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
