Anguish: Invisible Programming Language and Invisible Data Theft
At first glance, I'd consider it a (security) bug in Perl 6 that it permits tokens containing invisible characters, let alone consisting solely of invisible characters. Are there any other languages with this behavior?As a random example:    titan:~ geofft$ python3 -c "$(printf "\u2063") = 1"
      File "", line 1
         = 1
        ^
    SyntaxError: invalid character in identifier

If you change it to e.g. 00e9 ("é"), Python 3 permits the character, so it's not just a lower-ASCII thing.