analysis of entered characters (very basic)

MODULE analyzechar;
FROM InOut IMPORT WriteString, WriteLn, Read, Write;
TYPE
    letters = SET OF ['A'..'z'];
    digits = SET OF ['0'..'9'];
VAR
   allvowels, allconsonants: letters;
   alldigits : digits;
   ch : CHAR;
CONST
     empty = letters{};
     wovels = letters{'A', 'E', 'I', 'O', 'U'};
     consonants = letters{'A'..'Z'} -  wovels;
     dig = digits{'0'..'9'};

BEGIN
     allvowels := empty;
     allconsonants := empty;
     alldigits := digits{};
     WriteString('Enter the text block that you want to analyze');
     WriteLn; WriteString('Finish your entering with a dot!');
     WriteLn;
     Read(ch);
     WHILE ch <> '.' DO
     (*everything is written correctly*)
     (*but function CAP in some versions of the module2*)
     (*from some reason doesn't work corectly!*)
         IF CAP(ch) IN wovels THEN
          INCL(allvowels,ch)
        END;
        IF CAP(ch) IN consonants THEN
          INCL(allconsonants,ch)
        END;
        IF ch IN dig THEN
          INCL(alldigits,ch)
        END;
        Read(ch);
   END;
   WriteLn;
   WriteString('All the vowels, which are found in the text, are: ');
   WriteLn;
   FOR ch := 'A' TO 'Z' DO
      IF ch IN allvowels THEN
        Write(ch);
        WriteString('  ');
      END
   END;
   WriteLn;
   WriteString('All the consonants, which are found in the text, are: ');
   WriteLn;
   FOR ch := 'A' TO 'Z' DO
      IF ch IN allconsonants THEN
        Write(ch);
        WriteString('  ');
      END
   END;
   WriteLn;
   WriteString('All the numbers which have been found in the text, are: ');
   WriteLn;
   FOR ch := '0' TO '9' DO
      IF ch IN alldigits THEN
        Write(ch);
        WriteString('  ');
      END
   END;
END analyzechar.