Re[2]: ROT13 and alike

[Giuseppe Bilotta <bourbaki@bigfoot.com>]

>>\startscrambling[rot13]
>> \swaps a to m  n to z
>> \swaps A to M  N to Z
>>% also \swaps  <num> to <num>  <num> to <num>, checking for same length
>>\stopscrambling

HH> too tricky probably but `a to `m may work  

Nope.  The  transformation  I meant was not a->m, n->z, but "all codes
between  a  and  m included should be sequentially mapped to the codes
between  n  and z, and vice versa. The same for caps". Maybe with more
keywords, like:

\startscrambling[rot3]
  \swaps a to w with d to z
  \swaps x to z with a to c
\stopscrambling

But for simple swappings:

\startscrambling[carbo]
   \swaps a o, e i     % a <-> o, e <-> i
   \swaps b p, c g, d t, f v % etcetera
\stopscrambling