/* CRIAL
  SERIALIZER_BEGIN
    mpkutil_pack_str(packer, "$name");
    mpkutil_pack_str(packer, $code);
  END
  DESERIALIZER_BEGIN
    const char* v;
    size_t      vlen;
    if (!mpkutil_get_str(
          mpkutil_get_map_item_by_str(root, "$name"), &v, &vlen) ||
        strncmp(v, $code, vlen) != 0 || $code[vlen] != 0) {
      goto FAIL;
    }
  END
  PROPERTY subclass = "ground"

  SERIALIZER_BEGIN
    mpkutil_pack_str(packer, "$name");
    LOCOMMON_MSGPACK_PACK_ANY(packer, &base->$code);
  END
  DESERIALIZER_BEGIN
    if (!LOCOMMON_MSGPACK_UNPACK_ANY(
          mpkutil_get_map_item_by_str(root, "$name"), &base->$code)) {
      goto FAIL;
    }
  END
  PROPERTY id   = super.super.id
  PROPERTY pos  = super.super.pos
  PROPERTY size = super.size
  PROPERTY type = param.type
*/