public static void main(String args []) throws ParseException
  {
    EG1 parser = new EG1(System.in);
    while (true)
    {
      System.out.println("Reading from standard input...");
      System.out.print("Enter an expression like \u005c"1+(2+3)*4;\u005c" :");
      try
      {
        switch (EG1.one_line())
        {
          case 0 :
          System.out.println("OK.");
          break;
          case 1 :
          System.out.println("Goodbye.");
          break;
          default :
          break;
        }
      }
      catch (Exception e)
      {
        System.out.println("NOK.");
        System.out.println(e.getMessage());
        EG1.ReInit(System.in);
      }
      catch (Error e)
      {
        System.out.println("Oops.");
        System.out.println(e.getMessage());
        break;
      }
    }
  }