File: option-fold.scala

package info (click to toggle)
scala 2.11.12-5
  • links: PTS, VCS
  • area: main
  • in suites: bookworm
  • size: 62,828 kB
  • sloc: javascript: 28,808; java: 13,415; xml: 3,250; sh: 1,620; python: 756; makefile: 38; awk: 36; ansic: 6
file content (20 lines) | stat: -rw-r--r-- 470 bytes parent folder | download | duplicates (4) 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
 
object Test {
  sealed class A
  case object B extends A
  case class C(x: Int) extends A

  def f[T](x: Option[T]) = x.fold(List.empty[T])(List(_))
  def g(x: Option[A]) = x.fold(-1) {
    case B    => 0
    case C(x) => x
    case _    => ???
  }

  def main(args: Array[String]): Unit = {
    println(f(None))        //List()
    println(f(Some(5)))     //List(5)
    println(g(None))        //-1
    println(g(Some(B)))     //0
    println(g(Some(C(1))))  //1
  }
}