From: Ken Bloom <kbloom@...>
Date: 2007-04-23T05:10:08+09:00
Subject: Re: [QUIZ] Morse Code (#121)

Ruby Quiz <james@grayproductions.net> wrote:
> The three rules of Ruby Quiz:
> 
> 1.  Please do not post any solutions or spoiler discussion for this quiz until
> 48 hours have passed from the time on this message.
> 
> 2.  Support Ruby Quiz by submitting ideas as often as you can:
> 
> http://www.rubyquiz.com/
> 
> 3.  Enjoy!

Technically, I'm not breaking any rules in suggesting that the most
natural language for this problem is Prolog:

m('.-',    a).  m('-...',  b).  m('-.-.',  c).
m('-..',   d).  m('.',     e).  m('..-.',  f).
m('--.',   g).  m('....',  h).  m('..',    i).
m('.---',  j).  m('-.-',   k).  m('.-..',  l).
m('--',    m).  m('-.',    n).  m('---',   o).
m('.--.',  p).  m('--.-',  q).  m('.-.',   r).
m('...',   s).  m('-',     t).  m('..-',   u).
m('...-',  v).  m('.--',   w).  m('-..-',  x).
m('-.--',  y).  m('--..',  z).


morse_decode(Text,Translation):-atom_chars(Text,List),
   morse_i(List,TranslationList),
   atom_chars(Translation,TranslationList).
morse_encode(Text,Translation):-
   atom_chars(Translation,TranslationList),
   morse_i(List,TranslationList),
   atom_chars(Text,List).
morse_i([],[]).
morse_i(List,Translation):-m(First,Letter),atom_chars(First,FirstList),
      append(FirstList,RestList,List),Translation=[Letter|RestTrans],
      morse_i(RestList,RestTrans).

Examples of use:
morse_decode('...---...',X).
morse_decode('...---...',sos).
morse_encode(X,'sos').
morse_encode('...---...',sos).

--Ken Bloom