$a = 1;
$b = 2;

my $result1 = spaceship($a, $b);
print $result1 . "\n";

my $result2 = spaceship($b, $a);
print $result2 . "\n";


sub spaceship {
   my $x = shift;
   my $y = shift;

   if ($x < $y) {return -1}
   elsif ($x > $y) {return +1}
   else {return 0};
}

--output:--
-1 
1