上下文與Infix運算符綁定

Question

對於給定的抽象類Edge2D，我采用泛型類型T，並將上下文綁定到某個接口Point2DInterface。

abstract class Edge2D[T : Point2DInterface] {

  val p1: T
  val p2: T

  def length(): Double = {
    implicitly[Point2DInterface[T]].Sub(p1, p2)
  }
}

trait Point2DInterface[T] {
  def Sub(first: T, second: T): Double
}

通過以下實現，當T = DoublePoint2D時

object Implicits {

  implicit object DoublePoint2DInterface extends Point2DInterface[DoublePoint2D] {
    def Sub(first: DoublePoint2D, second: DoublePoint2D): Double = {
      first - second
    }
  }
}

如何為T創建中綴運算符？ 所以我可以寫

  def length(): Double = {
    p1 - p2
  }

不管上一個問題，我想知道，有沒有辦法結合隱式對象的實現？ 例如，組合DoublePoint2DInterface和IntPoint2DInterface。

object Implicits {

  implicit object DoublePoint2DInterface extends Point2DInterface[DoublePoint2D] {
    def Sub(first: DoublePoint2D, second: DoublePoint2D): Double = {
      first - second
    }
  }

implicit object IntPoint2DInterface extends Point2DInterface[IntPoint2D] {
    def Sub(first: IntPoint2D, second: IntPoint2D): Double = {
      first - second
    }
    }

Answer 1

如何為T創建中綴運算符？

implicit class Point2DInterfaceOps[T](x: T)(implicit evidence: Point2DInterfaceOps[T]) {
  def -(y: T) = evidence.Sub(x, y)
  ...
}

不管上一個問題，我想知道，有沒有辦法結合隱式對象的實現？

使它成為泛型，即用Point2D[T: Numeric]替換IntPoint2D和DoublePoint2D Point2D[T: Numeric]和隱implicit def numericPoint2D[T: Numeric]: Point2DInterface[Point2D[T]]的兩個隱式對象implicit def numericPoint2D[T: Numeric]: Point2DInterface[Point2D[T]]