Monad and Functor

Monad.scala

//https://medium.com/beingprofessional/understanding-functor-and-monad-with-a-bag-of-peanuts-8fa702b3f69e


object Monad extends App {
//  Functor + unit+ Flatmap = Monad
  case class Sugar(weight: Int)
  case class Bag[A](content: A) {
    def map[B](f: A => B): Bag[B] = Bag(f(content))
    def flatMap[B](f: A => Bag[B]): Bag[B] = f(content)
  }
  def double(sugar: Sugar): Bag[Sugar] = Bag(Sugar(sugar.weight * 2))
  def half(sugar: Sugar): Sugar = Sugar(sugar.weight / 2)

  val halfSugarBag: Bag[Sugar] = Bag(Sugar(1)).map(sugar => half(sugar))
  val doubleSugarBag = Bag(Sugar(1)).flatMap(sugar => double(sugar))
}