String typeOf(String st) throws Exception
   {
      //handle define, the word after it is a procedure
      //to ensure that everything after define is still procedure
      if (reservedWords.contains(st))
      {
         return "RESERVED WORD";
      }
      else if (Character.isDigit(st.charAt(0)))
      {
         return "DIGIT";
      }
      else if (specialSymbol.contains(st))
      {
         return "PROCEDURE";
      }
      else
      {
         return "IDENTIFIER";
      }
      //add here if you want to check procedure example: member?, null?
   }