use Date::Set;

# when the event occurs: every friday.
my $set = Date::Set->event ( rule => 'FREQ=WEEKLY;BYDAY=FR');

# in what period we want occurences: december 2002
my $period = Date::Set->period (time => ['20021201', '20021231']);

my @occurs = $set->during (at => $period)->list;
print "occurences on ", join (" ,", @occurs), "\n";

##</code><code>##

use Date::Set;

$a = Date::Set->event();
$a->event( rule => 'FREQ=MONTHLY;INTERVAL=2;' );
$a->event( start => '20030801',
           end   => '20031201' );
@list = $a->list;

foreach (@list) {
  print "$_\n";
}

##</code><code>##

$a = Date::Set->event( rule => 'FREQ=YEARLY;INTERVAL=2' );
$a->during( start => '20030801', end => '20200801' );
print $a . "\n";