Task

Implement a   Vigenère cypher,   both encryption and decryption.

The program should handle keys and text of unequal length,
and should capitalize everything and discard non-alphabetic characters. 

(If your program handles non-alphabetic characters in another way,
make a note of it.)



Related tasks

   Caesar cipher
   Rot-13
   Substitution Cipher


sub s2v ($s) { $s.uc.comb(/ <[ A..Z ]> /)».ord »-» 65 }
sub v2s (@v) { (@v »%» 26 »+» 65)».chr.join }
 
sub blacken ($red, $key) { v2s(s2v($red) »+» s2v($key)) }
sub redden  ($blk, $key) { v2s(s2v($blk) »-» s2v($key)) }
 
my $red = "Beware the Jabberwock, my son! The jaws that bite, the claws that catch!";
my $key = "Vigenere Cipher!!!";
 
say $red;
say my $black = blacken($red, $key);
say redden($black, $key);