Philipp Haller, EPFL and Stanford University
Experimenting with pattern matching in Scala's interpreter (REPL). Below is both the code entered into the REPL as well as the REPL's output.
abstract class Tree[+T]
case class Binary[T](el: T, left: Tree[T], right: Tree[T]) extends Tree[T]
case object Empty extends Tree[Nothing]
val tree = Binary(6, Binary(5, Empty, Empty), Binary(10, Empty, Empty))
tree match {
case Binary(el, l, r) => println(l)
}
def inOrder[T](t: Tree[T]): List[T] = t match {
case Empty => List()
case Binary(el, l, r) => inOrder(l) ::: List(el) ::: inOrder(r)
}
inOrder(tree)
scala> inOrder(tree)
res1: List[Int] = List(5, 6, 10)