se DateTime::Format::Strptime;

my $dt_format = DateTime::Format::Strptime->new(pattern => "%d-%m-%Y"); 

sub val_date {
    my $dt = shift;
    $dt =~ s|[./]|-|g; # '.' and '/' become '-' for simplicity
    return $dt_format->parse_datetime($dt);
}

my $s = '01-02-2007';
my $dt = val_date($s);
if ($dt) {
    print "valid date\n";
} else {
    print "not a date\n";
}