Monads http://scabl.blogspot.com/2013/02/monads-in-scala-1.html http://scabl.blogspot.com/2013/03/monads-in-scala-2.html

Maybe

sealed trait Maybe[+A] {
 
// >>=
def flatMap[B](f: A => Maybe[B]): Maybe[B]
}
 
case class Just[+A](a: A) extends Maybe[A] {
override def flatMap[B](f: A => Maybe[B]) = f(a)
}
 
// Nothing in the Haskel example
case object MaybeNot extends Maybe[Nothing] {
override def flatMap[B](f: Nothing => Maybe[B]) = MaybeNot
}