        PrintError("expected escape: \\uxxxx");
        return wabt::Result::Error;
      }
      uint16_t code = 0;
      for (int i = 0; i < 4; ++i) {
        c = ReadChar();
        int cval;
        if (c >= '0' && c <= '9') {
          cval = c - '0';
        } else if (c >= 'a' && c <= 'f') {
          cval = c - 'a' + 10;
        } else if (c >= 'A' && c <= 'F') {
          cval = c - 'A' + 10;
        } else {
          PrintError("expected hex char");