scalaz.Equal是如何解决的
scalaz.Equal是如何解决的,scala,implicit,scalaz,Scala,Implicit,Scalaz,scalaz包中有Equal对象: package scalaz object Equal extends EqualLow { // ... implicit def Tuple3Equal[A: Equal, B: Equal, C: Equal]: Equal[(A, B, C)] = equal { case ((a1, b1, c1), (a2, b2, c2)) => a1 ≟ a2 && b1 ≟ b2 && c1 ≟ c
scalaz
包中有Equal
对象:
package scalaz
object Equal extends EqualLow {
// ...
implicit def Tuple3Equal[A: Equal, B: Equal, C: Equal]: Equal[(A, B, C)] = equal {
case ((a1, b1, c1), (a2, b2, c2)) => a1 ≟ a2 && b1 ≟ b2 && c1 ≟ c2
}
//...
}
编译器如何知道在调用时将调用隐式def Tuple3Equal
方法:
import scalaz._
import Scalaz._
implicitly[Equal[Tuple3[Int,Int,Int]]]
//or
(1,2,3).=== (1,2,3)
请注意,我只导入
scalaz.\uuz
包和scalaz.\uz
对象,并且没有包含隐式的显式导入scalaz.Equal.\uu。,因为在查找Foo
类型的隐式时,Foo
的伴随对象总是被选中。有关隐式解析的完整描述,请参阅。因为在查找类型为Foo
的隐式时,Foo
的伴生对象总是被选中。有关隐式解析的完整描述,请参见