Returning a flagvalue would have many of the same problems as the Null Flag bug pattern we discussed last time.
返回一个标志值将引起许多与我们上次讨论的空标志错误模式一样的错误。
2
AdArray 0x2000 a flagvalue combined with another data type constant. Indicates an array of that other data type.
一个标记值,它是与其他的数据类型常数结合在一起使用的。它指明了包含其它数据类型的数组。
3
If we had added a getValue method to class Leaf, we would either have to return some sort of flagvalue indicating that the method application is non-sensical or actually throw an exception.