scala – AnyVal的目的是什么？

Value classes are classes whose instances are not represented as
objects by the underlying host system. All value classes inherit from
class AnyVal.

所以,也许问题是,如果一切都是一个对象,为什么我不关心某些东西是否被表示,即实现为一个对象？这是实现细节中的实现.

但是,我们不要假装,当然你关心.你从不专攻吗？

规范继续：

Scala implementations need to provide the value classes Unit,Boolean,
Double,Float,Long,Int,Char,Short,and Byte (but are free to
provide others as well).

因此,除了所需值类的枚举之外,对AnyVal的测试是有意义的.

也就是说,你必须接受@ drexin的答案,因为如果你没有使用值类进行扩展方法,那么你就不会真正生活. (从某种意义上讲,生活起来.)

SIP的动机：

…classes in Scala that can get completely inlined,so operations on
these classes have zero overhead compared to external methods. Some
use cases for inlined classes are:

1. Inlined implicit wrappers. Methods on those wrappers would be
   translated to extension methods.
2. New numeric classes,such as unsigned ints. There would no longer
   need to be a boxing overhead for such classes. So this is similar to
   value classes in .NET.
3. Classes representing units of measure. Again,no boxing overhead
   would be incurred for these classes.

您可以将扩展方法本身标记为@inline,并且所有内容都是内联的：没有对象包装器,并且您的小方法是内联的.

我每天都使用这个功能.昨天我遇到了一个bug.该错误已经修复.这就是说它是一个很酷的功能,Scala人会从Coursera中抽出时间来消除它中的一个小错误.

这让我想起,我忘了问,这不是Coursera测验问题,是吗？