Subject: How to define a CALSCALE?

From: Matthias Laabs <[email-masked]>
Date: Wed, 5 Nov 2003 16:33:27 +0100

Hi,

I am interested in writing a CALSCALE for JALALI(persian) calendar. Where can 
I find information on how to write or where to propose it. Is the Gregorian 
CALSCALE defined somewhere?

Thanks in advance,

Matthias

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From: [email-masked]
Date: Wed, 5 Nov 2003 11:48:56 -0500

> CALSCALE defined somewhere?

Start with RFC 2445, Section 4.7.1 Calendar Scale for the actual property. 

From there you will need to also look at the DATE (Section 4.3.4 Date) 
bits and maybe the DATE-TIME (Section 4.3.5 Date-Time) bits so they are 
correctly defined for JALLAI.  (Im assuming the time scales are the 
same...)

Finally you will need to look at any necessary changes for the recurrence 
grammar (Section 4.3.10 Recurrence Rule) bits to define the correct 
grammar sub-parts.  That is, you will want to adjust stuff like BYDAY 
values of "shanb", "yeksh", etc. and make sure the limits on values is 
adjusted accordingly.

Once you've done this, you write it up using the RFC template for drafts 
and submit it for review.  More detailed info can be found at 
http://www.rfc-editor.org/howtopub.html

Bruce
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From: John Stracke <[email-masked]>
Date: Wed, 05 Nov 2003 12:12:42 -0500

[email-masked] wrote:

> Finally you will need to look at any necessary changes for the 
> recurrence grammar (Section 4.3.10 Recurrence Rule) bits to define the 
> correct grammar sub-parts.  That is, you will want to adjust stuff 
> like BYDAY values of "shanb", "yeksh", etc. and make sure the limits 
> on values is adjusted accordingly. 

Or you might consider specifying that BYDAY still use the Gregorian 
values for days of the week, to reduce the complexity for implementers 
who want to support both scales.  It'd be annoying to humans reading the 
Persian text/calendars, but that's going to be less common.  I imagine 
they'd rather have more choice of implementations to use.

(There is a 1-1 correspondence, right? Shanb is always the same as 
Sunday, yeksh the same as Monday, etc.? I can imagine a calendar where 
the last day or two of the year is not part of any week, and the week 
always gets reset on the first day of the year; such a calendar scale 
couldn't use the Gregorian names, since there wouldn't be a 1-1 
correspondence.)

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From: Nathaniel Borenstein <[email-masked]>
Date: Fri, 7 Nov 2003 20:54:45 -0500

I think this would be a very illuminating enterprise.  Although we 
shouldn't need to delay CAP for it as long as we resolve the 
CAP-VERSION ambiguities, I think it would be very good if several 
people were beginning to think about how to define new CALSCALEs.

There are lots of fun issues.  For example, the Hebrew calendar 
includes the delightful concept of a leap month which is *not* the last 
month of the year.  Makes you want to be careful with using numeric 
values for years, doesn't it?  -- Nathaniel