klaeufer

// http://underscore.io/blog/posts/2015/04/14/free-monads-are-simple.html
// updated version for scalaz 7.2.x where Free automatically applies the
// Coyoneda transform

import scalaz.{Free, ~>, Id}
import scalaz.std.list._
import scalaz.syntax.traverse._

type UserId = Int
type UserName = String

igstan

trait Factory[T] {
  def create: T
}

object Factory {
  implicit def stringFactory: Factory[String] = new Factory[String] {
    def create = "foo"
  }

  implicit def intFactory: Factory[Int] = new Factory[Int] {