Stephen Colebourne wrote:
On 26 January 2018 at 07:46, Paul Eggert <eggert@cs.ucla.edu> wrote:
Meno Hochschild wrote:
I have adjusted my tzdb-compiler (Time4J) such that it looks if all rule lines referencing the same name (here: Eire) contain any negative dst offsets. If yes then let's assume summer time for SAVE=0 and winter time for SAVE < 0. So I can still work with old unchanged CLDR-entries for getting "Irish Standard Time" in summer.
This sounds like a good idea regardless of whether we make changes to zic input. Couldn't OpenJDK do the same?
Such an approach is merely adding an even more subtle API to TZDB, one where a mixture of positive and negative SAVE values would cause chaos.
What sort of chaos, exactly? Meno Hochschild is not reporting any chaos.
Meno's approach with an extra column actually tackles the heart of the problem by providing a stable key that can be used to link the two projects.
Such a key could be given in a separate data file, which could be used by zi parsers that do not support negative DST offsets, or that have other specialized requirements. That would be less disruptive than changing zic input format for purposes unrelated to zic. For this particular issue I'm hoping that we can use an even less-disruptive approach, such as the one proposed here: https://mm.icann.org/pipermail/tz/2018-January/026002.html which should avoid the need for an extra column or an extra file.