scalaでmapを畳み込みを使って作ってみる

Main.scala

object Main {

  def main(args: Array[String]): Unit = {

    def map[T, U](ls: List[T])(f: T => U): List[U] = ls.foldRight(Nil: List[U])((x, y) => f(x) :: y)

    println(map(List(1, 2, 3))(x => x * 2))

  }

}