Regional database connections

gistfile1.scala

object Regional {
  case class IOM[M, A](unwrap: IO[A])
  case class Q[M](c: Connection)

  def iomMonad[M]: Monad[({type λ[α] = IOM[M, α]})#λ] =
    new Monad[({type f[a] = IOM[M, a]})#f] {
      def pure[A](a: => A) = IOM[M, A](a.point[IO])
      def bind[A, B](m: IOM[M, A], f: A => IOM[M, B]) =
        IOM(m.unwrap >>= (x => f(x).unwrap))
    }
  def executeQuery[M](q: Q[M], s: String): IOM[M, ResultSet] =
    IOM(io { q.c.executeQuery(s) })
  def withConnection[M, A](u: url, f: Q[M] => IOM[M, A]): IOM[M, A] =
    IOM(openConnection(u).bracket(closeConnection, c => f(Q(c)).unwrap))
  def runIOM(x: Forall[({type λ[μ] = IOM[μ, A]})#λ]): IO[A] =
    x.unwrap
    
}