use DateTime;
use strict;
use warnings;
my $str = '2003/11/12';
my( $y, $m, $d ) = qw[ 2003 11 12 ]; # this part magic, use split
$d = DateTime->new( year => $y, month => $m, day => $d);
warn $d->ymd;
$d->add(days => 6);
die $d->ymd;
__END__
2003-11-12 at C:\dev\loose\datetime3.pl line 7.
2003-11-18 at C:\dev\loose\datetime3.pl line 9.