sub roll_die
{
    my ($sides, $min) = @_;

    return int(rand($sides - $min + 1) + $min);
}

sub my_roller
{
    my ($num_dice, $sides, $min_value, $num_to_drop) = @_;
    $num_dice ||= 3;
    $min_value ||= 1;
    $num_to_drop ||= 0;

    return () unless $num_dice >= 1;
    return () unless $num_dice > $num_to_drop;

    my @values =
        sort { $a <=> $b }
        map { roll_die($sides, $min_value) } 1 .. $num_dice;
 
    return @values[$num_to_drop .. $#values];
}

my @values = my_roller(4, 6, 2, 1);
print "@values\n";