Request for Adding Buddhist Calendar System

Thanomsub Noppaburana donga.nb at
Mon Mar 15 06:13:20 GMT 2010

Thanks for your fast reply and any suggestions.

2010/3/14 John Layt <johnlayt at>

> Hi Thanomsub,
> I'm the official maintainer of Calendar Systems in KDE.  Thank you for
> these
> patches, the Buddhist calendar is on my to-do list for 4.5, but I had a
> number
> of questions about how to do it right so it's great to have expert help :-)
> At a quick look, there's a few issues that spring to mind based on my
> previous
> research.
> * QDate
> You use QDate for the Gregorian calendar base calculations, which as you
> note
> causes an issue with QDate's hybrid Julian/Gregorian calendar.  However, we
> do
> have a KCalendarSystemGregorianProleptic class which implements a 'pure'
> Gregorian calculation which you could use instead.  If you look at
> KCalendarSystemIndianNational calendar you can see an example of this.
> Ok, I will look at KCalendarSystemGregorianProleptic as you suggested.

> * Year Numbering
> The big questions is do we need to adjust for the different epochs and New
> Years days used historically and keep the year numbers the same as
> observed?
> In other words, are we implementing an 'ideal' calendar as it exists today,
> or
> do we want an 'historic' calendar to show the dates as they really were in
> the
> past (like QDate sort-of does)?
> My understanding of the epochs/New Years used is:
>  1888 to 1912 used the Rattanakosin Era epoch April 6 1782 AD
>  1912 to 1941 used the Buddhist Era epoch April 1 545 BC
>  1941 to now  uses the Buddhist Era epoch January 1 545 BC
> We could implement 'pure' private classes for each of these calculations,
> then
> have a separate "Thai Solar" class made available to the users that
> switches
> between them based on the date.  Or we could just have a single class with
> all
> the calculations in one place switched on date.  Or we could just support
> the
> current calculation and not worry about historical accuracy.
> How do Thai people deal with this in daily life, for example in school text
> books, do they refer to dates before 1941 or 1912 by the old year numbers
> or
> the new year numbers?
> Oh, it seems you have more informations on this calendar :-)
As your mentions, i think we should use the modern epoch
since we thought this Thai Buddhist Era has no different from Gregorian
except Year (+543AD) .

> * Naming
> You call it the Buddhist calendar, but I think I would prefer to call it
> something like the "Thai (Buddhist Era)" or "Thai Solar" (as Wikipedia does
> as there is actually the
> Buddhist lunisolar calendar (
> which we may implement one day and I don't want them to get confused.  Any
> other suggestions?
> Ok, You're right. We should call this calendar system to "Thai (Buddhist
And it is the great news that you will be develops Buddhist lunisolar
it would be useful.

* Month and day names.
> When referring to the months and days in English, is it more common to use
> the
> English names or transcriptions of the Thai names?  So would you expect to
> see
> January or Makarakhom?
> For me, i want to use January instead of Makarakhom.
I don't think that Thai peoples would be use Makarakhom in case of using the
programs with no Localization.

Best Regards,
Thanomsub Noppaburana.

p.s.Waiting for opinions from other Thai developers.

OK, I think that's enough enough questions for now :-)  I'm looking forward
> to
> your reply.
> For initial discussions, the mailing list is always the best starting
> point,
> but the best place for submitting code is via our Review Board at
> where it's easier for people to look at and
> comment
> on the code in context.
> Many thanks,
> John.
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