具有复杂多态性边界的Scala语法。

Question

比如说，有没有一个scala机制来简化长多态性边界？

case class RecordTypeX(...) extends A with B with C with D with E with F // defined in my project
case class RecordTypey(...) extends A with B with C with D with E with F // defined in a dependency package

class MyClass1[T <: A with B with C with D with E with F](x:T) {...}
class MyClass2[T <: A with B with C with D with E with F](x:T) {...}
...

val x = RecordTypeX(...)
val y = RecordTypeY(...)
val instance = new MyClass1(x)
val instance = new MyClass1(y)

理想情况下，如果能有一个类似于

type Processable=A with B with C with D with E with F
case class RecordTypeX(...) extends Processable // defined in my project
case class RecordTypeY(...) extends A with B with C with D with E with F // defined in a dependency package

class MyClass1[T <: Processable]() {...}
class MyClass2[T <: Processable]() {...}
...

val x = RecordTypeX(...)
val y = RecordTypeY(...)
val instance = new MyClass1(x)
val instance = new MyClass1(y)

有什么解决办法吗？

注:引入一个新的特质，结合所有其他的特质，并将其扩展到所有可能的类，如

trait Processable extends A with B with C with D with E with F

不能成为一个解决方案，因为我不能修改RecordTypeY。

Answer 1

你可以做到两者结合。

trait A
trait B
trait C
trait D
trait E
trait F

type Processable = A with B with C with D with E with F
trait ProcessableI extends A with B with C with D with E with F

final case class RecordTypeX(s: String) extends ProcessableI
final case class RecordTypeY(i: Int) extends A with B with C with D with E with F

class MyClass[T <: Processable](x: T)

val x = RecordTypeX("foo")
val y = RecordTypeY(3)
val instance1 = new MyClass(x)
val instance2 = new MyClass(y)