1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
|
/** Test contributed by Stefan Zeiger showing that HLists can be
* specialized.
*/
sealed trait HList {
type Self <: HList
type |: [E] = HCons[E, Self]
final def |: [@specialized E](elem: E): |: [E] = new HCons[E, Self](elem, this.asInstanceOf[Self])
def m[@specialized E, T <: AnyRef](x: E): T = null.asInstanceOf[T]
}
final class HCons[@specialized H, T <: HList](val head: H, val tail: T) extends HList {
type Self = HCons[H, T]
}
final object HNil extends HList {
type Self = HNil.type
}
object Test extends App {
val l1 = new HCons(42, "foo" |: HNil)
println(l1.getClass)
val l2 = 42 |: "abc" |: HNil
println(l2.getClass)
}
|
