Krasnyanskiy · April 16, 2016 16:09
diff --git a/FoldDemo.scala b/FoldDemo.scala
 abstract class List[+T] {
  def flatMap[U](f: T => List[U]): List[U] = this match {
    case x :: xs => f(x) ++ xs.flatMap(f) // ++ is a concat operator
    case Nil => Nil
  }
 }
	abstract class List[+T] {
	def flatMap[U](f: T => List[U]): List[U] = this match {
	case x :: xs => f(x) ++ xs.flatMap(f) // ++ is a concat operator
	case Nil => Nil
	}
	}