/* Sound Morse code via the PC buzzer.           June 2011 */
MORSE: procedure options (main);
   declare (i, j) fixed binary;
   declare buzz character (1) static initial ('07'x);
   declare text character (100) varying,
      c character (1);
   declare alphabet character (36) static initial (
      'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789');
   declare morse_character character(5) varying;
   declare morse_codes(36) character(5) varying static initial (
      /* Letters A-Z */
      '.-',    '-...',   '-.-.',   '-..',    '.',
      '..-.',  '--.',    '....',   '..',     '.---',
      '-.-',   '.-..',   '--',     '-.',     '---',
      '--.-',  '--.-',   '.-.',    '...',    '-',
      '..-',   '...-',   '.--',    '-..-',   '-.--',
      '--..',
      /* Digits 0-9 */
      '-----', '.----',  '..---', '...--',   '....-',
      '.....', '-....',  '--...', '---..',   '----.' );

   put skip list ('Please type the text to be transmitted:');
   get edit (text) (L);

   do i = 1 to length (text);
      c = substr(text, i, 1);
      j = index(alphabet, uppercase(c));
      if j > 0 then
         do;
            morse_character = morse_codes(j);
            put skip list (morse_character); /* Display the Morse. */
            call send_morse (morse_character);
         end;
   end;

send_morse: procedure (morse_character);
   declare morse_character character(*) varying;
   declare i fixed binary;

   do i = 1 to length(morse_character);
      if substr(morse_character, 1, 1) = '-' then
         put skip edit (buzz, ' ', buzz) (a(1), A, skip, a(1));
      else
         put skip edit (buzz, ' ') (a(1));
      delay (1000); /* Delay one period. */
   end;
   delay (1000);
      /* Making a delay of 2 periods after each English letter. */
end send_morse;

END MORSE;