[VCARDDAV] Non-gregorian dates

Cyrus Daboo <cyrus@daboo.name> Sun, 17 January 2010 20:25 UTC

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Date: Sun, 17 Jan 2010 15:25:30 -0800
From: Cyrus Daboo <cyrus@daboo.name>
To: CardDAV <vcarddav@ietf.org>
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Subject: [VCARDDAV] Non-gregorian dates
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Hi folks,
I have heard from a number of people who would like to specify 
non-Gregorian dates (and partial dates) in vCard properties. Whilst I do 
not proposed we add explicit support for that in vCard 4, I would suggest 
we follow the iCalendar approach and define a CALSCALE parameter that can 
be used on any property that includes a date value (either a DATE/DATETIME 
value type or TEXT). That parameter would be defined with a single value, 
"GREGORIAN", which would be the default if is in not present. We would add 
an IANA registry for new values. We would need to add a requirement for 
clients about how to deal with CALSCALE values they do not recognize - 
basically ignore the property or treat it as text.

NB this is important for things like birthdays which, if specified in a 
non-Gregorian calendar, do not always map to the same Gregorian date 
year-to-year.

-- 
Cyrus Daboo