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Re: TimeZones and politics Re: How to tell (in advance) if adate-time is ambiguous?

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From:
Bill Ricker
Date:
July 12, 2017 18:10
Subject:
Re: TimeZones and politics Re: How to tell (in advance) if adate-time is ambiguous?
Message ID:
CAAbKA3WjtV4hbV=vW1UM0ffrqXK0823BnR4GVTQ-MTNdp5BKzg@mail.gmail.com
> Well, first of all, I did not want to insult or even criticize anybody.
> Please forgive me if my wording even made the slightest impression of
> doing so - regrettably, I am not a native English speaker.

In which case, you are doing very well, i would not have guessed.
( If I replied in French it would be painfully obvious i had merely
poor schooling in same. )

Related,

> Of course, I meant "ever" instead of "never" in the sentence above.

Idiomatically exchanging those (and various other double negations) is
regrettably becoming acceptable in informal usage in recent decades.
Which is even more confusing for second-language folks than for
irony-impaired native speakers.
    [ And one can argue if my parenthetical addition to the sentence
subject changes the required number-agreement of the verb from 'is' to
'are'. Or more simply that i overuse parentheticals with both braces
and em-dashes. I plead Guilty to the latter. :-) ]

> Actually, I am feeling the highest respect towards the experts who are
> helping with the time zone database updates, are bringing them to a
> machine readable form and are writing software modules which are dealing
> with the overwhelming bunch of time calculating oddities in an
> impressive manner. I am really very grateful for that and can't thank
> those volunteer experts enough.
>
> I just wanted to say that the statement "... the change happens at 2:00
> in Chicago ... " might not be sufficient for my case because I am trying
> to write a web application which deals with date and time calculations
> in local time zones around the world, and that I'd like the application
> to behave well (as far as possible) even in the weirdest cases.

That is pretty much the English expansion what the Olson/TZinfo file
says the EDT rule for the America/Chicago zone is.  Other rules may
say something else.

>>>  and the next law could determine the switch to
>>> happen at 08:48:27 am, and

Theoretically possible ...

>> It could in theory, but would be beyond atypical.
>> (Why? Perhaps a(n) hereditary national leader wants to honor the
>> moment of his father's birth?)

> Yes, I had something like that in my mind (although I doubt that I will
> have the application translated into the languages which are spoken in
> such regions :-))

Even worse, users anywhere may wish to schedule a meeting (or
whatever) on Pyongyang time (or whereever) without even being in that
Locale, so may reasonably request an event in some other TZ than
theirs or system native.E.g. if i wanted to tape the recent FIFA cup
winners' cup final in Petrograd/StPetersburg off a satellite feed,
entering it in TZ of the upload would make some sense.

>> (The file format and software should handle  08:48,not sure about 08:48:27 ?)

> Thanks for the hint. I have never looked into a time zone file yet
> (hoping that I could solve all my problems by using modules instead of
> doing my own thing).

Looking at  the Olson/TZinfo data is a massive rabbit-hole but my what
interesting data it is.

> I am feeling that it eventually would be better to use the weirdest
> examples (risking making a complete fool of myself if missing something)
> instead of my time zone (which is Europe/Berlin which has been
> well-behaving so far, like America / Chicago, so is probably not an
> example I should use to explain my problems ...).

Indeed, that can be useful to explore the edgecases. Kathmandu is a good one.
The non-political 'Etc/GMT+nn' zones with inverted sign zones
(inverted wrto UTC defined zones) are also good test cases to break
programs :-).


> I have chosen Venezuela because I am not an expert in this field, and it
> was the first time I heard of a time shift that was *purely* a political
> statement, so I have been shocked backed then. Until the moment when it
> happened, I had considered such a thing impossible, so I can still
> remember it (and still can't believe it - somehow :-)).

And a good example it is !  (Plenty more down the rabbit hole.)

> This is very interesting; I didn't even know that quarter-hour offsets
> do exist.

Heh. We try to forget :-).
Currently there are only x:45, but there may have been x:15's previously.

>> Yes, it's political.

Aside on politics - opposition to DST isn't new either.

My great-grandfather was among the many US dairy farmers who railed
against DST adoption.  The cows wanted to be milked as soon after dawn
as he could get on his stool, the cows didn't care about clocks let
alone punch clocks, so a farmer needed to be up with the rooster or
before.  And would work through every daylight hour in summer. If he
seemingly had leisure time before sunset that meant he should use the
time to buy someone else's standing hay and go mow and bale it ! So
the stores to which he delivered corn and milk etc changing their
hours twice per year inconvenienced him.


-- 
Bill Ricker
bill.n1vux@gmail.com
https://www.linkedin.com/in/n1vux

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