Basic Scala Memoïzation

Memo

  case class Memo[A, B](f: A => B) extends Function1[A, B] {
    private val cache = scala.collection.mutable.Map.empty[A, B]
    def apply(x: A) = cache.getOrElseUpdate(x, f(x))
  }

  val fibonacci: Memo[Int, Int] = Memo {
    case 0 => 0
    case 1 => 1
    case n => fibonacci(n - 1) + fibonacci(n - 2)
  }