NAME
Date::Easter - Calculates Easter for any given year
SYNOPSIS
use Date::Easter;
($month, $day) = julian_easter(1752);
($month, $day) = easter(1753);
($month, $day) = gregorian_easter(1753);
($month, $day) = orthodox_easter(1823);
DESCRIPTION
Calculates Easter for a given year.
easter() is, for the moment, an alias to gregorian_easter(), since
that's what most people use now. The thought was to somehow know which
of the other methods to call, that that proved to be rather sticky.
Date::Easter provides the following functions:
julian_easter
( $month, $day ) = julian_easter( $year );
Returns the month and day of easter in the given year, in the Julian
calendar.
gregorian_easter
( $month, $day ) = gregorian_easter( $year );
Returns the month and day of easter in the given year, in the Gregorian
calendar, which is what most of the world uses.
easter
( $month, $day ) = easter( $year );
Returns the month and day of easter in the given year, in the Gregorian
calendar, which is what most of the world uses.
orthodox_easter
( $month, $day ) = orthodox_easter( $year );
Returns the month and day of easter in the given year, in the Orthodox
calendar.
From code by Pascalis Ligdas, based on original code by Apostolos
Syropoulos
AUTHOR
Rich Bowen <
[email protected]>
To Do
Since the dates that various countries switched to the Gregorian
calendar vary greatly, it's hard to figure out when to use which method.
Perhaps some sort of locale checking would be cool?
I need to test the Julian easter calculations, but I'm a little confused
as to the difference between the Orthodox Easter and the Julian Easter.
I need to read some more.
The use of localtime and timelocal locks us into the epoch, which is a
rather silly limitation. Need to move to Date::DayOfWeek or other module
to calculate the day of the week. This should immediately make the
module usable back to the beginning of celebration of Easter.
Other Comments
Yes, Date::Manip already has code in it to do this. But Date::Manip is
very big, and rather slow. I needed something faster and smaller, and
did not need all that other stuff. And I have a real interest in date
calculations, so I thought this would be fun. Date::Manip is a very cool
module. I use it myself.
See also
http://www.pauahtun.org/CalendarFAQ/cal/node3.html for more
details on calculating Easter.
And many thanks to Simon Cozens who provided me with the code for the
orthodox_easter function.
The tests are taken from a table at
http://www.chariot.net.au/~gmarts/eastcalc.htm
The script 'easter' is just a simple way to find out when easter falls
in a given year. Type 'easter' to find easter for this year, and 'easter
1983' to find when easter falls in 1983.
