private static String parseStringLiteral(String token) {
    if (token.length() < 2) {
      return "";
    }
    StringBuilder sb = new StringBuilder(token.length() - 2);
    int i = 1;
    while (i < token.length() - 1) {
      char c = token.charAt(i);
      if (c == '\\') {
        c = token.charAt(++i);
        if (c == 'n') sb.append('\n');
        else if (c == 't') sb.append('\t');
        else if (c == 'f') sb.append('\f');
        else sb.append(c);
      } else {
        sb.append(c);
      }
      i++;
    }
    return sb.toString();
  }
private static String parseStringLiteral(String token)