基于泛型的重载方法

问题描述

我想重载基于泛型的方法-像这样：

case class Indexed2dArr[Dim0Type,Dim1Type] (
  indices: (List[Dim0Type],List[Dim1Type]),array: List[List[Float]],) {
  def getSliceAtIndexLocation(i: Dim0Type): (List[Dim1Type],List[Float]) = ???
  def getSliceAtIndexLocation(i: Dim1Type): (List[Dim0Type],List[Float]) = ???
}

因此，如果使用参数getSliceAtIndexLocation调用Dim0Type，它将返回原始数组的一维切片，索引为Dim1Type。反之亦然，使用Dim1Type进行呼叫。

这会引发double deFinition编译器错误-类型擦除后，这两种方法具有相同的类型，该类型为(i: Object): Tuple2。有没有有效的方法可以解决这个问题？还是不可能直接解决？

解决方法

尝试DummyImplicit

case class Indexed2dArr[Dim0Type,Dim1Type] (
  indices: (List[Dim0Type],List[Dim1Type]),array: List[List[Float]],) {
  def getSliceAtIndexLocation(i: Dim0Type): (List[Dim1Type],List[Float]) = ???
  def getSliceAtIndexLocation(i: Dim1Type)(implicit 
    di: DummyImplicit): (List[Dim0Type],List[Float]) = ???
}

或type class模式

case class Indexed2dArr[Dim0Type,) {
  def getSliceAtIndexLocation[A](i: A)(implicit tc: TC[A]): tc.Out = tc(i)

  trait TC[A] {
    type B
    type Out = TC.MkOut[B]
    def apply(i: A): Out
  }
  object TC {
    type MkOut[B] = (List[B],List[Float])

    type Aux[A,B0] = TC[A] { type B = B0 }
    def instance[A,B0](f: A => MkOut[B0]): Aux[A,B0] = new TC[A] {
      override type B = B0
      override def apply(i: A): Out = f(i)
    }
  
    implicit val dim0Type: Aux[Dim0Type,Dim1Type] = instance(i => ???)
    implicit val dim1Type: Aux[Dim1Type,Dim0Type] = instance(i => ???)
  }
}

或magnet模式

import scala.language.implicitConversions

case class Indexed2dArr[Dim0Type,) {
  def getSliceAtIndexLocation(m: Magnet): m.Out = m()

  trait Magnet {
    type B
    type Out = Magnet.MkOut[B]
    def apply(): Out
  }
  object Magnet {
    type MkOut[B] = (List[B],List[Float])

    type Aux[B0] = Magnet { type B = B0 }
    def instance[B0](x: MkOut[B0]): Aux[B0] = new Magnet {
      override type B = B0
      override def apply(): Out = x
    }

    implicit def dim0Type(i: Dim0Type): Aux[Dim1Type] = instance(???)
    implicit def dim1Type(i: Dim1Type): Aux[Dim0Type] = instance(???)
  }
}