[tz] [PATCH 3/3] * europe (Europe/Vaduz): Now a link to Europe/Zurich.

Clive D.W. Feather clive at davros.org
Tue Sep 10 01:13:50 UTC 2013

Guy Harris said:
>>> Rather, we should have markers of when zonal times, as opposed to LMT,
>>> first came into effect. For places where we know the legal change point,
>>> such as the UK, this is a "happened at" date-time. For places where we
>>> don't, it's a "happened sometime before" date-time, and we probably want a
>>> way to distinguish these.
> Now, whether that's "the city" or "the region covered by the tzid" is another matter; what should we do if a given locale covered by a tzid didn't all adopt (in some sense) zonal time all at once?

That's a good question. I suggest the answer is that you need to be able to
put a range in there as an alternative to a single date.

> Also, what sense of "adopt" should we, well, *adopt*?  "Adopted by a government for a region that includes all of the region in question" (which needn't always be a national government), or should we include common use (for which it might be more difficult to choose a date and time)?

I don't have a good answer to that. For the UK, I'd say that statute and
common law trumps usage, so there's a single transition date irrespective
of what some people did (the leading law case on the matter was to do with
the fact that the courthouse clock used "railway" time rather than LMT).
If there is some kind of statutory basis, use that - if it varies across
the region, use the range facility I suggest above.

If we don't have a good idea when people changed, then we're no worse off
than we are right now.

Clive D.W. Feather          | If you lie to the compiler,
Email: clive at davros.org     | it will get its revenge.
Web: http://www.davros.org  |   - Henry Spencer
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