Scala中子类的特征中的默认类型类实现

Question

I have the following relations:

trait Instrument

trait EquityOption extends Instrument { ... }
case class CallEquityOption(...) extends EquityOption
case class PutEquityOption(...) extends EquityOption

trait Priceable[I <: Instrument] { def price(I : Instrument) }

I can use exactly the same implementation of Priceable for the case classes CallEquityOption and PutEquityOption . By having a match case to differentiation between the Call... and Put... . However, if I try to implement it directly as Priceable[EquityOption] under object EquityOption , the implicit cannot be found since it doesn't exactly match the type.

How can I make it work without needing to duplicate code?

Answer 1

您必须证明您可以为EquityOption每个子类型提供实例。

implicit def allEquityOptions[T <: EquityOption]: Pricable[T] = ???