Question

对于给定的抽象类Edge2D，我采用的是泛型类型T. 将上下文绑定到某个接口Point2DInterface。

object Implicits {

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

使用以下实现时，T = DoublePoint2D

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

如何为T创建中缀运算符？所以我可以写

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
    }
    }

不管上一个问题，我想知道，有没有办法结合起来隐式对象的实现？例如，组合DoublePoint2DInterface和IntPoint2DInterface。

document.getElementById("dtBody1")

Answer 1

如何为T创建中缀运算符？

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

不管上一个问题，我想知道，有没有办法组合隐式对象的实现？

将其设为通用，即将IntPoint2D和DoublePoint2D替换为Point2D[T: Numeric]，将两个隐含对象替换为implicit def numericPoint2D[T: Numeric]: Point2DInterface[Point2D[T]]

上下文与Infix运算符绑定

1 个答案: