* Ihor Radchenko <yanta...@posteo.net> [2023-01-31 16:46]: > Specifying just @Europe/Berlin is ambiguous around the daylight savings > transition.
Sorry, I cannot see practical example why is it ambiguous. Unless programmer does not take all information in account, it is not ambigous. People on this planet agree on time zones in advance, so there are few changes that people cannot plan in advance. Those changes are recorded in time zone databases. Unless you consider programming without using time zone databases, then I can surely understand that it will be ambiguous. > To resolve the ambiguous, we should either introduce DST flag DST is property of time zone. You do not introduce it, you read it from time zone database. But maybe you wish to implement time zones in Org. In that case I can only say "Good luck" to accuracy. > or simply allow specifying the UTC offset directly. UTC offset is not reliable, and is also derived from time zone database. Try it out, make tests, create experiments, compare if that approach will be usable, publish it and put in for testing. > Since DST is not guaranteed to be +-1 hour (it may be more, up to 1 > full day), DST flag is more problematic than UTC offset. Is not if you always pull the latest tz database. Political changes are pretty careful to people and decisions are announced ahead of the change. So do you think that you cannot use tz database in Emacs Lisp? Maybe it will be necessary to make new Lisp functions defined in C language, accessing the time zone database. But it is not for Org to implement new tz database in Emacs Lisp, that will become unmaintainable work. But why not, if you wish, but accuracy of time will be questionable. Researching following pages will give you idea with what you are trying to deal with on Org level: How to Read the tz Database: https://data.iana.org/time-zones/tz-how-to.html List of tz database time zones - Wikipedia: https://en.wikipedia.org/wiki/List_of_tz_database_time_zones tz database - Wikipedia: https://en.wikipedia.org/wiki/Tz_database -- Jean Take action in Free Software Foundation campaigns: https://www.fsf.org/campaigns In support of Richard M. Stallman https://stallmansupport.org/
