Transaction.scala

/**
  * A Transaction can produce an effect and a result using STMOps. This represents
  * an atomic operation performed using the STMOps, getting/setting data, etc.
  * Using a wrapper allows for use of different effects, and serialisation.
  */
trait Transaction[A] {
  
  def apply[F[_]: Monad](implicit stm: STMOps[F]): F[A]

  def map[B](f: A => B): Transaction[B] = {
    val t = this
    new Transaction[B] {
      override def apply[F[_] : Monad](implicit stm: STMOps[F]): F[B] = t[F].map(f)
    }
  }

  def flatMap[B](f: A => Transaction[B]): Transaction[B] = {
    val t = this
    new Transaction[B] {
      override def apply[F[_] : Monad](implicit stm: STMOps[F]): F[B] = t[F].flatMap(a => f(a)[F])
    }
  }

}