throws Throwable
  public Value evalObject(Env env)    throws Throwable  {    Value value;    if (_var.isGlobal()) {      value = env.getGlobalValue(_name);      if (value == null || ! value.isset()) {        value = env.createObject();        env.setGlobalValue(_name, value);      }    } else {      value = env.getValue(_name);      if (value == null || ! value.isset()) {        value = env.createObject();        env.setValue(_name, value);      }    }    return value;  }