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Re: [whatwg] <time>

From: Leif Halvard Silli <lhs@malform.no>
Date: Sat, 14 Mar 2009 02:49:06 +0100
Message-ID: <49BB0D12.9080600@malform.no>
To: David Singer <singer@apple.com>
CC: Robert J Burns <rob@robburns.com>, Julian Reschke <julian.reschke@gmx.de>, Geoffrey Sneddon <foolistbar@googlemail.com>, Charles McCathieNevile <chaals@opera.com>, Toby A Inkster <mail@tobyinkster.co.uk>, whatwg@lists.whatwg.org, "public-html@w3.org" <public-html@w3.org>
David Singer 2009-03-14 01.37:
> At 19:26  -0500 13/03/09, Robert J Burns wrote:
>> The chief accomplishments of ISO 8601 is the ability to represent 
>> dates in a uniform manner and in defining the Gregorian calendar from 
>> 1582 to 9999 in an unambiguous way. Beyond those dates it leaves 
>> things imprecise and ambiguous.
> 
> You keep saying this, but I have yet to hear what is imprecise or 
> ambiguous.  Could you be more clear?

I thought you admitted that "c) that parsing the body text as 8601 
may be dangerous if it's notated the same way but not (possibly 
proleptic) Gregorian;" [1]

This is very simple: The calendar has no validity before that 
date. The Gregorian date 1582-10-14 doesn't exist except in theory 
- and in situations where history doesn't matter, such as in 
astronomy, which I understand uses the proleptic Gregorian calendar.

Martin Luther died on 18th of February 1546 [2]. That is a Julian 
date. On the Proleptic Gregorian calendar, he died on the 28th of 
February. If you took a wheel that had a perimeter of 1 year, and 
rolled it back - starting on 18th of February this year -  until 
1546 on the Proleptic Gregorian calendar, you would land on 8th - 
eight - of February on the Julian calendar.

Noone went over the old  dates and "corrected" them. 18th of 
February is the day he died, and it continues to be reckoned as 
that day even if 28th is the day he "literally" died.

If we then start to use the Proleptic Gregorian calendar, the 
author must first "undo" this and record that Martin Luther died 
on 28th of February. But at the same time, software must undo 
that, again, and present the date as 18th of February, if the 
presentation is supposed to have any relevance to how history has 
been recored.

I am sorry if this was too small babysteps to you are anyone.

[1] http://www.w3.org/mid/p06240863c5e035dda4cc@%5B17.202.35.52%5D
[2] http://en.wikipedia.org/wiki/Martin_Luther
-- 
leif halvard silli
Received on Saturday, 14 March 2009 01:50:13 UTC

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