edwardGunawan

trait SomeTrait {
 def fetchAll: Future[Seq[String]]
}

edwardGunawan

implicit class ListOp[A](lst: List[A]) {
  def filterBy(p: A => Predicate): List[A] = lst.filter{ p(_) match {
      case Predicate.Keep => true
      case Predicate.Discard => false
    }
  }
}

edwardGunawan

List(1,2,4).filter{p => if(p > 2) Predicate.Keep else Predicate.Disacrd}

edwardGunawan

def filter[A](p: A => Predicate): List[A]

edwardGunawan

sealed trait Predicate 
object Predicate {
  case object Keep extends Predicate
  case object Discard extends Predicate
}

edwardGunawan

trait List[A] {
  def filter(p : A => Boolean): List[A]
}

edwardGunawan

trait SomeInterface {
  def someFunction(): Future[Either[Throwable, String]]
}

edwardGunawan

trait SomeInterface {
  def someFunction(): EitherT[Future, Throwable, String]
}

edwardGunawan

def doSomething(res: Future[Either[Throwable, Option[A]]]) = res match {
   case Success(a) =>
      a match {
        case Left(ex) => 
        case Right(b) =>  b match {
                                case Some(c) => 
                                case None =>
                              }

        }

edwardGunawan

def buildRunner
  ((req,Resp) => ctx.TransactionContext)
  ((resp, ctx.rtx.Transaction) => Final[Context])
  (resp => Unit): Runner[ctx.Transaction, rtx.TransacitonResponse] = new Runner[ctx.Transaction, rtx.TransactionResponse] { 
   override def run((ctx.Transaction, rtx.TransactionResponse) => Response): Req => Resp = ???
  }
  
  
trait Runner[T, F] {
 def run((T,F) => Response): Req => Resp