基于泛型的重载方法 [英] Overloading methods based on generics
问题描述
我想重载基于泛型的方法-像这样:
I'd like to overload a method based on generics - so something like this:
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 Dim0Type
调用 getSliceAtIndexLocation
,它将返回原始数组的一维切片,索引为 Dim1Type 代码>.反之亦然,使用
Dim1Type
进行调用.
So if getSliceAtIndexLocation
is called with a parameter of Dim0Type
, it returns a single-dimensioned slice of the orginal array, with an index of Dim1Type
. And vice-versa for calling with Dim1Type
.
这将引发双重定义
编译器错误-类型擦除后,这两种方法具有相同的类型,此类型为(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?
This raises a double definition
compiler error - that the two methods have the same type after type erasure, this type being (i: Object): Tuple2
. Is there a valid way to wrangle this or is it straight-up impossible?
推荐答案
尝试使用 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]) = ???
}
或类型类模式
case class Indexed2dArr[Dim0Type, Dim1Type] (
indices: (List[Dim0Type], List[Dim1Type]),
array: List[List[Float]],
) {
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 => ???)
}
}
或磁铁模式
import scala.language.implicitConversions
case class Indexed2dArr[Dim0Type, Dim1Type] (
indices: (List[Dim0Type], List[Dim1Type]),
array: List[List[Float]],
) {
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(???)
}
}
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