A start on a package for doing monadic IO in scala

io.scala

package object io {
  sealed trait IO[A] {
    def unsafePerformIO: A
  }

  object IO {
    def apply[A](a: => A): IO[A] = new IO[A] {
      def unsafePerformIO = a
    }
  }

  implicit val IOMonad = new Monad[IO] {
    def pure[A](a: => A): IO[A] = IO(a)
    def bind[A,B](a: IO[A], f: A => IO[B]): IO[B] = IO {
      implicitly[Monad[Function0]].bind(() => a.unsafePerformIO, (x:A) => () => f(x).unsafePerformIO)()
    }
  }
  
  def bracket[A,B,C](init: IO[A], fin: A => IO[B], body: A => IO[C]): IO[C] =
    for { a <- init
          c <- body(a)
          _ <- fin(a) }
      yield c
}