$x = 'ii';
$y = 'ii';

sub Roman {

=pod
    This doesn't check for validity, as the
    subtraction rule is always honored, even
    for I before M if you want to do that.
    Roman numerals generally allow I only before
    V or X for the subtraction rule, X before
    an L or a C, and C before a D or an M.

    If you need to check validity, it'd be a
    task suitable for a separate sub since
    this one should be able to handle horked
    but workable values by design, just in
    case. Heck, this doesn't even check for
    the existence of invalid characters. It
    just ignores them.
=cut

    my $z = 0;
    my @foo = uc(shift) =~ /(M+|D+|C+|L+|X+|V+|I+)/g;
    my %value = (
        'M' => 1000,
        'D' => 500,
        'C' => 100,
        'L' => 50,
        'X' => 10,
        'V' => 5,
        'I' => 1,
    );
    for ( my $i = 0; $i < scalar @foo; $i++ ) {
        my $ch = substr $foo[$i], 0, 1;
        my $v = $value{$ch};
        my $nxt_ch = '';
        my $nxt_v = -1;
        if ( defined ( $foo[$i + 1] ) ) {
            $nxt_ch = substr( $foo[$i + 1], 0, 1 );
            $nxt_v = $value{$nxt_ch};
        }
        foreach ( 1..length $foo[$i] ) {
            if ( $nxt_v > $v ) {
                $z -= $value{$ch};
            } else {
                $z += $value{$ch};
            }
         }
    }
    return $z;
}

printf "The result is: %d\n", (Roman $x) + (Roman $y);
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