Samuel,
This calendar information is some of my brainstorming.
Microsoft has implemented calendar classes. The open-source Joda-Time
project also has calendar classes and a chronology class. I have not
analyzed the details. The Apache implementation of calendaring should
be independent of Microsoft libraries.
In my brief analysis of the Joda-Time documentation, there may be a
significant deficiency in the architecture - trying to maintain
compatibility with JDK (Java Development Kit) datetime functions and use
of a microsecond time clock. Some kind of solar-calendar time factoring
would help a long-lasting chronology infrastructure. The Gregorian
Algorithm of 400-year cycles is currently the most stable algorithm in
wide use.
I have not downloaded the Joda-Time project hosted at Sourceforge for
analysis. The possibilities might prove interesting.
Whatever we choose for a time continuum (like the Joda-Time project)
should be independent of the applied calendar. Each calendar class will
have its own rules to handle specific and arbitrary adjustments. But
the time continuum should be a long-lasting (many millennia of time
consistency). All calendars should have reference points to the chosen
time continuum. This allows interoperability between calendars.
Steven J. Hathaway
On 4/14/2012 11:19 AM, Samuel Medeiros wrote:
Steven,
in addition to consider the difference between Julian and Gregorian
Calendar patterns before 1582, I think is necessary remember that
dates manipulations before March 1, 4 AD, when the modern Julian
calendar rules were adopted, are not accurate. Furthermore, before 45
BC, the Julian calendar did not even exist.
Sincerely,
Samuel Queiroz
Em 14 de abril de 2012 18:10, Samuel Medeiros <ccc.sam...@gmail.com
<mailto:ccc.sam...@gmail.com>> escreveu:
Steven,
thank you for this reference.
I understood the Proleptic Gregorian Calendar is used to dates
before 1582, when the Gregorian Calendar effectively was used.
As the Julian Calendar had a big error (by considering all
centuries as leaps), there are difference to consider between
Gregorian and Julian dates before that year (1582).
Sincerely,
Samuel Queiroz
Em 12 de abril de 2012 20:16, <shath...@e-z.net
<mailto:shath...@e-z.net>> escreveu:
Samuel,
The year BC-1 is the year before AD-1.
See: http://wikipedia.org/wiki/Proleptic_Gregorian_calendar
This gives you some insight if we are going to use Gregorian
Calendar
years before AD-1.
Sincerely,
Steven J. Hathaway
--
Samuel de Medeiros Queiroz
Formal Methods Group (GMF - UFCG - Brazil)
