private static String toRange(char c,int low,int high)
  /**
  *  If 'c' is outside the range 'low' through 'high' (inclusive),
  *  return its representation as Java escape.
  *  Otherwise return 'c' as a one-character string.
  *
  *  @param  c the character.
  *  @return Representaton of c within the range.
  */
    {
      switch(c)
      {
        case '\b': return("\\b");
        case '\f': return("\\f");
        case '\n': return("\\n");
        case '\r': return("\\r");
        case '\t': return("\\t");
        default:
          if (c<low || c>high)
          {
            String u = "000" + Integer.toHexString(c);
            return("\\u" + u.substring(u.length()-4,u.length()));
          }
          else return Character.toString(c);
      }
    }