Scala example source code file (Catchable.scala)

This example Scala source code file (Catchable.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

catchable, throwable

The Catchable.scala Scala example source code

package scalaz

////
/**
 * A context in which exceptions can be caught and thrown.
 *
 * This class places no other class constraints on `F`, but it should be the
 * case that exceptions raised via `fail` are caught by the nearest surrounding
 * `attempt` and returned as a `Left`. In addition to catching explicitly
 * raised exceptions via `fail`, we expect that `attempt` catch ambient
 * exceptions that might occur when 'evaluating' an `F`.
 *
 * We can state the requirement that `attempt` catch all ambient exceptions
 * by stipulating that for all total functions of the form
 * `g: forall A . F[Throwable \/ A] => B`, `g compose attempt` is also
 * total.
 */
////
trait Catchable[F[_]]  { self =>
  ////

  def attempt[A](f: F[A]): F[Throwable \/ A]
  def fail[A](err: Throwable): F[A]
  // derived functions

  ////
  val catchableSyntax = new scalaz.syntax.CatchableSyntax[F] { def F = Catchable.this }
}

object Catchable {
  @inline def apply[F[_]](implicit F: Catchable[F]): Catchable[F] = F

  ////

  ////
}