Scala example source code file (MonadError.scala)

This example Scala source code file (MonadError.scala) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Scala by Example" ^TM.

Learn more about this Scala project at its project page.

Java - Scala tags/keywords

boolean, equal, fea, monaderror, monaderrorlaw

The MonadError.scala Scala example source code

package scalaz

////
/**
 *
 */
////
trait MonadError[F[_], S] extends Monad[F] { self =>
  ////

  def raiseError[A](e: S): F[A]
  def handleError[A](fa: F[A])(f: S => F[A]): F[A]

  trait MonadErrorLaw {
    def raisedErrorsHandled[A](e: S, f: S => F[A])(implicit FEA: Equal[F[A]]): Boolean =
      FEA.equal(handleError(raiseError(e))(f), f(e))
    def errorsRaised[A](a: A, e: S)(implicit FEA: Equal[F[A]]): Boolean =
      FEA.equal(bind(point(a))(_ => raiseError(e)), raiseError(e))
    def errorsStopComputation[A](e: S, a: A)(implicit FEA: Equal[F[A]]): Boolean =
      FEA.equal(bind(raiseError(e))(_ => point(a)), raiseError(e))
  }
  def monadErrorLaw = new MonadErrorLaw {}

  ////
  val monadErrorSyntax = new scalaz.syntax.MonadErrorSyntax[F, S] { def F = MonadError.this }
}

object MonadError {
  @inline def apply[F[_], S](implicit F: MonadError[F, S]): MonadError[F, S] = F

  ////

  ////
}