lexicalPermutations templates
  when <|=1> do [1] !
  otherwise
    n is $;
    p is [ $n - 1 -> # ];
    1..$n -> templates
      k is $;
      $p... -> [ $k, $... -> templates
        when <|$k..> do $+1!
        otherwise $!
      end] !
    end!
end lexicalPermutations

alpha is ['ABCD'...];
[ $alpha::length -> lexicalPermutations -> '$alpha($)...;' ] !