导出Scala枚举的Cats命令

Question

我想要Scala的Order的通用Cats Enumeration。我试过了

implicit def enumOrder[E <: Enumeration, V <: E#Value]: cats.Order[V] = new cats.Order[V] {
  def compare(x: V, y: V): Int = x.compare(y)
}

但我明白了

[error] overloaded method value compare with alternatives:
[error]   ((that: _1.Value)Int) forSome { val _1: E } <and>
[error]   (that: _1.Value)Int
[error]  cannot be applied to (V)
[error]     def compare(x: V, y: V): Int = x.compare(y)
[error]                                      ^

有谁知道我怎么能实现这个？谢谢

NB，我刚刚问了一个similar question，我认为这会产生一个答案，我会很聪明地适用于这个问题，但事实并非如此。

Answer 1

implicit def enumOrder[V <: Enumeration#Value](implicit ord: Ordering[V]): cats.Order[V] = new cats.Order[V] {
  def compare(x: V, y: V): Int = ord.compare(x, y)
}

要么

implicit def enumOrder[V <: Enumeration#Value](implicit ord: Ordering[V]): cats.Order[V] = ord.compare(_, _)