On Sun 2021-05-23T22:43:46+0100 Clive D.W. Feather via tz hath writ:
I would actually say that, if we're going to do something like that, there should be a way to put a "not valid before" marker into the zone data and have the functions return either an error or a clearly nonsense answer.
My impression is that the answers provided by creating such an interface would be indistinguishable from the LMT of Kew Observatory for London, and the city longitudes for everything else. Those are already akin to nonsense or a declaration of invalidity. The disruption caused by creating such an interface and the maintenance of the cutoff dates would be two reasons to say that what LMT values are in existence now already implements this idea. -- Steve Allen <sla@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 https://www.ucolick.org/~sla/ Hgt +250 m