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
30
31
32
33
|
object Test{
abstract class Number
case class Int(n: scala.Int) extends Number
case class Double(d: scala.Double) extends Number
trait Term[+a]
case class Cell[a](var x: a) extends Term[a]
case class NumTerm(val n: Number) extends Term[Number]
class IntTerm(n: Int) extends NumTerm(n) with Term[Int]
def f[a](t:Term[a], c:Cell[a]): Unit = {
t match {
case NumTerm(n) => c.x = Double(1.0)
}
t match {
// presently testing that this gets past the parser: eventually
// it should actually work.
case Cell[a](x: Int) => c.x = 5
}
}
val x:Term[Number] = NumTerm(Int(5))
def main(args: Array[String]): Unit = {
val cell = Cell[Int](Int(6))
Console.println(cell)
f[Int](new IntTerm(Int(5)), cell)
Console.println(cell)
}
}
|
