[tz] [tz-announce] 2018f release of tz code and data available

Steve Allen sla at ucolick.org
Sun Oct 21 03:00:12 UTC 2018

On Sat 2018-10-20T21:55:50+0100 Stephen Colebourne hath writ:
> The java.time.* code exposes the local time that the transition occurs.
> This can be represented within the bounds 00:00 to 24:00. There is no way
> to represent 25:00 or negatives.
> https://docs.oracle.com/javase/8/docs/api/java/time/zone/ZoneOffsetTransitionRule.html

Many examples of non-normalized dates and times exist in historical
literature.  One example is 1970 January -1 and December 35 at
The subsequent page has January -6 and December 40, and not to be
forgotten in other civil use was 1712 February 30

> As such, the tzdb parser would have to convert 25:00 and try to reinterpret
> it as the next day within the valid bounds, which is far from ideal. It
> would be much better for the upstream source to represent the data in a
> more standard and backwards compatible way.

People did these sorts of things, and not just in astronomy.  The
choice is whether or not a modern parser will be able to read what
people actually did or go into a mode resembling denial.

Steve Allen                    <sla at ucolick.org>              WGS-84 (GPS)
UCO/Lick Observatory--ISB 260  Natural Sciences II, Room 165  Lat  +36.99855
1156 High Street               Voice: +1 831 459 3046         Lng -122.06015
Santa Cruz, CA 95064           http://www.ucolick.org/~sla/   Hgt +250 m

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