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RE: Here's the regex for the xs:dateTime datatype

• From: "Toby Considine" <Toby.Considine@gmail.com>
• To: "'Norman Gray'" <norman@astro.gla.ac.uk>,"'Peter Flynn'" <peter@s...>
• Date: Wed, 15 Aug 2018 11:04:40 -0400

Well noted, Peter & Norman.  I was not aware that GMT bumped the day at
noon...

This does not even touch on the problems of time zones, and that the machine
readable registry of time zones and DST rules is a server that as of three
years ago was a hobby. I remember because folks were worries about his
upcoming retirement...

Time Zones are not just the even 24 hours evenly distributed by geography
except for slight deformations for political boundaries, but are off by
quarter and third of an hour increments in some places. Two countries still
arbitrarily announce change to DST a week or so ahead of time each year. 

This may seem a trivial distinction, but there was a time not so many years
ago when the California Power Market neglected to buy power for the 25th
hour one Fall....

One can say just use Universal Time, but so long as things are scheduled to
support people, and people live in the public time, there will always be a
need to communicate unambiguously when is power or water purchased, when do
local markets close, when do options in resource markets expire... These
issues consumed a third of the time the IETF / OASIS joint work to support
smart energy.

In the USA, multiple states are considering changing time zones, or doing
away with DST. This means crossing an internal border may be a two hour time
jump some times of the year...

For those interested in time, Europe is seeking comments on rearranging
Summer Time: 
https://ec.europa.eu/eusurvey/runner/2018-summertime-arrangements


tc

-----Original Message-----
From: Norman Gray [mailto:norman@astro.gla.ac.uk] 
Sent: Tuesday, August 14, 2018 5:21 PM
To: Peter Flynn <peter@silmaril.ie>
Cc: xml-dev@lists.xml.org
Subject: Re:  Here's the regex for the xs:dateTime datatype


On 14 Aug 2018, at 21:44, Peter Flynn wrote:

> On 14/08/18 17:39, Toby Considine wrote:
>
>> And as we wander down the road toward the one true solution, be sure 
>> to consider the non-Gregorian issues that can be quite engrossing.
>
>
> Indeed they can. In the CELT project, we have old Irish annals of 
> varying sorts, using Anno Mundi which sets year zero as 5199BCE.

...and of course Greenwich Mean Time (naval/astronomical, pre-1925), which
looks just like everyone else's notion of the calendar, but which has the
day number increment at noon.

Or the post-1920s Orthodox calendar, which looks like everyone else's
calendar but which sneakily throws off the previous message's regexp for
leap years by having a different rule from everyone else.

(this is fun -- I've got a whole book-ful of these, with conversion
algorithms available for the seriously keen).

Best wishes,

Norman


--
Norman Gray  :  https://nxg.me.uk

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• Follow-Ups:
  • Re: Here's the regex for the xs:dateTime datatype
    • From: John Cowan <johnwcowan@gmail.com>
  • RE: Here's the regex for the xs:dateTime datatype
    • From: "Toby Considine" <Toby.Considine@gmail.com>

• References:
  • Here's the regex for the xs:dateTime datatype
    • From: "Costello, Roger L." <costello@mitre.org>
  • Re: Here's the regex for the xs:dateTime datatype
    • From: Michael Kay <mike@saxonica.com>
  • Re: Here's the regex for the xs:dateTime datatype
    • From: "Liam R. E. Quin" <liam@fromoldbooks.org>
  • Re: Here's the regex for the xs:dateTime datatype
    • From: David Carlisle <d.p.carlisle@gmail.com>
  • Re: Here's the regex for the xs:dateTime datatype
    • From: "Liam R. E. Quin" <liam@fromoldbooks.org>
  • RE: Here's the regex for the xs:dateTime datatype
    • From: "Toby Considine" <Toby.Considine@gmail.com>
  • Re: Here's the regex for the xs:dateTime datatype
    • From: Peter Flynn <peter@silmaril.ie>
  • Re: Here's the regex for the xs:dateTime datatype
    • From: "Norman Gray" <norman@astro.gla.ac.uk>