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Re: [whatwg] <time>

From: Leif Halvard Silli <lhs@malform.no>
Date: Fri, 13 Mar 2009 04:02:13 +0100
Message-ID: <49B9CCB5.9020201@malform.no>
To: Andy Mabbett <andy@pigsonthewing.org.uk>
CC: whatwg@lists.whatwg.org, public-html@w3.org
Andy Mabbett 2009-03-12 22.51:
> In message <p06240841c5deeed58fb1@[17.202.35.52]>, David Singer:
>> At 17:53  +0100 12/03/09, Julian Reschke wrote:

>>> We aren't the subject matter experts on calendars and date formats, so
>>> why do we pretend we are?
>> I agree.  As I said before, if we want a tag to express that a date is
>> in a different calendar system, we are not going either to invent those
>> tags or define the notation and conversion of those calendar systems
>> here.  We can and should rely on groups like ISO.
> 
> If we're still discussing my proposal; I have not suggested "inventing
> tags" nor "defining notations", merely allowing space for others (such
> as ISO) to do so. What I wrote was:

>         [ snip ] One way to do so would be allow something like:
> 
>                 <time schema="[schema-name]" datetime="[value]">[date in
>                 plain text]</time>
> 
>         where the schema defaults to ISO 8601 if not stated, and the
>         whole element is treated as simply:
> 
>                 [date in plain text]
> 
>         if the schema is unrecognised; thereby ensuring backwards
>         compatibility. That way, if a hypothetical ISO- or other
>         standard for Julian dates emerges in the future, authors may
>         simply start to use it without any revision to HTML 5 being
>         required.

Perhaps we don't need any names for Julian. The simplest schema I 
could think of would be a numerical one. For instance, between 
29th of February 1900 and and 28th of February 2100, the Julian 
date is thirteen days "behind" the Gregorian.

Then, one could have a sheme called "13", which meant that 13 days 
should be added to the date in question, in order to find the 
Gregorian date.

Example: The next Russian Orthodox Christmas day could either be 
noted as Gregorian:

<time
   datetime="2010-01-07">Christmas Day</time>

Or as Julian:

<time scheme="13"
   datetime="2009-12-25">Christmas Day</time>

Both these would then point to the same day on the proleptic 
calendar.  In the latter example, the number 13 is used to tell by 
how many days the date given is behind Gregorian date.

For the period between year 200 and year 300 there is no 
calendaric difference. For the years between 100 and 200, the 
Julian calendar is 1 day ahead, hence the scheme="-1". Between 2nd 
January 45 BC until 29. of February year 100 CE, the difference is 
-2.
-- 
leif halvard silli
Received on Friday, 13 March 2009 03:03:35 UTC

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