monad1.scala

case class ScalaChan[A](value: A)

implicit def ScalaChanEqual[A]: Equal[ScalaChan[A]] = equalA

implicit def ScalaChanShow[A]: Show[ScalaChan[A]] = showA

implicit lazy val ScalaChanPure: Pure[ScalaChan] = new Pure[ScalaChan] {
  def pure[A](a: => A): ScalaChan[A] = ScalaChan(a)
}

implicit lazy val ScalaChanBind: Bind[ScalaChan] = new Bind[ScalaChan] {
  def bind[A, B](a: ScalaChan[A], f: A => ScalaChan[B]): ScalaChan[B] = f(a.value)
}

def f[A[_]: Monad, B: Semigroup](a: A[B]) = for {
  i <- a
  j <- a
} yield i |+| j

f(100.some) assert_=== 200.some

f(ScalaChan("Scala")) assert_=== ScalaChan("ScalaScala")

implicit lazy val ScalaChanMonad: Monad[ScalaChan] = new Monad[ScalaChan] {
  def pure[A](a: => A): ScalaChan[A] = ScalaChan(a)
  def bind[A, B](a: ScalaChan[A], f: A => ScalaChan[B]): ScalaChan[B] = f(a.value)
}

monad2.scala

'Scalaz.wrapNel.getOrElseM('Scala.some.wrapNel) assert_=== NonEmptyList('Scala)

'Scalaz.wrapNel.getOrElseM(none.wrapNel) assert_=== NonEmptyList('Scalaz)

monad3.scala

true.some.ifM('Scalaz.some, 'Scala.some) assert_=== Option('Scalaz)

nel(false, true, false).ifM('イカちゃん.wrapNel, 'Scalaちゃん.wrapNel) assert_=== NonEmptyList('Scalaちゃん,'イカちゃん,'Scalaちゃん)

monad4.scala

'Z'.some.replicate[List](5) assert_=== List(Option('Z'), Option('Z'), Option('Z'), Option('Z'), Option('Z'))

'Z'.some.replicateM[List](3) assert_=== Option(List('Z', 'Z', 'Z'))

monad5.scala

nel(1, 2, 3).foldLeftM(mzero[Int])(_ |+| _ |> (i => (i % 2 === 0).option(i)))

nel(1, 2, 3).foldLeftM(mzero[Int])(_.replicate[List](_)) assert_=== List(0, 0, 0, 0, 0, 0)