Okay I ported whatever is in the last post of that thread to Perl: (only tested with this year though)

print easter_date(2005);

sub easter_date {
        my $Year = shift;
         $G = $Year % 19; 
         $C = int($Year / 100); 
         $H = int($C - ($C / 4) - ((8*$C+13) / 25) + 19*$G + 15) % 30;
+ 
         $I = $H - int($H / 28)*(1 - int($H / 28)*int(29 / ($H + 1))*(
+int(21 - $G) / 11)); 
         $J = ($Year + int($Year/4) + $I + 2 - $C + int($C/4)) % 7; 
         $L = $I - $J; 
         $m = 3 + int(($L + 40) / 44); 
         $d = $L + 28 - 31 * (int($m / 4)); 
         $y = $Year; 
         return sprintf("%04d-%02d-%02d", $y, $m, $d); 
}
[download]

DON'T USE THIS CODE!

I wrote a quick and dirty compare of the date calculated by this sub against the list in the zip file at Easter Sunday Dates and found it to be 22% inaccurate. Good enough for PHP perhaps? *grin*

Yes I get that the thread was a joke :)

Update: see Re^3: What about Easter? by themage for an updated subroutine which does not produce any erros when compared to the list.

--
Murray Barton
Do not seek to follow in the footsteps of the wise. Seek what they sought. -Basho

There is a small error in the PHP version, that pg ported here: <updated, wrong name>.

The line


$H = int($C - ($C / 4) - ((8*$C+13) / 25) + 19*$G + 15) % 30;
[download]


Should be:


$H = ($C - int($C / 4) - int((8*$C+13) / 25) + 19*$G + 15) % 30;
[download]


The final sub sould look like:



sub easter_date {
  my $Year = shift;
  my ($G,$C,$H,$I,$J,$L)="0"x6;
  $G = $Year % 19;
  $C = int($Year / 100);
  $H = ($C - int($C / 4) - int((8*$C+13) / 25) + 19*$G + 15) % 30;
  $I = $H - int($H / 28)*(1 - int($H / 28)*int(29 / ($H + 1))*(int(21 
+- $G) / 11));
  $J = ($Year + int($Year/4) + $I + 2 - $C + int($C/4)) % 7;
  $L = $I - $J;
  my $m = 3 + int(($L + 40) / 44);
  my $d = $L + 28 - 31 * (int($m / 4));
  my $y = $Year;
  return sprintf("%04d-%02d-%02d", $y, $m, $d);
}
[download]

This way, I think that it should be ok. What you think greenFox?


TheMage
http://themage.bliker.com

That fixed it. With your updated sub I got 0 errors for 2517 dates. Well spotted.

--
Murray Barton
Do not seek to follow in the footsteps of the wise. Seek what they sought. -Basho

Too SLOW! Must be in CORE!