Created
February 20, 2017 08:10
-
-
Save pandaforme/2b913d5fedde6861e30b39fe476873ce to your computer and use it in GitHub Desktop.
Free your context
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| import scala.concurrent.{ExecutionContext, Future} | |
| import scala.util.Try | |
| import cats.implicits._ | |
| import simulacrum.typeclass | |
| sealed trait Error | |
| case class SomethingWrong(e: Throwable) extends Error | |
| @typeclass | |
| trait Capture[F[_]] { | |
| def capture[A](a: => A): F[A] | |
| } | |
| object Capture { | |
| implicit def futureCapture(implicit ec: ExecutionContext) = new Capture[Future] { | |
| override def capture[A](a: => A): Future[A] = Future(a)(ec) | |
| } | |
| implicit val tryCapture = new Capture[Try] { | |
| override def capture[A](a: => A): Try[A] = Try(a) | |
| } | |
| implicit val optionCapture = new Capture[Option] { | |
| override def capture[A](a: => A): Option[A] = Option(a) | |
| } | |
| implicit val eitherCapture = new Capture[Either[Error, ?]] { | |
| override def capture[A](a: => A): Either[Error, A] = { | |
| val fatal: Either[Throwable, A] = Either.catchNonFatal(a) | |
| val either: Either[Error, A] = fatal.leftMap(SomethingWrong(_)) | |
| either | |
| } | |
| } | |
| implicit def fgCapture[F[_]: Capture, G[_]: Capture] = new Capture[λ[α => F[G[α]]]] { | |
| override def capture[A](a: => A): F[G[A]] = { | |
| implicitly[Capture[F]].capture(implicitly[Capture[G]].capture(a)) | |
| } | |
| } | |
| } | |
| object Main extends App { | |
| import scala.concurrent.ExecutionContext.Implicits.global | |
| import Capture._ | |
| def getUser[F[_]: Capture](id: String): F[String] = { | |
| Capture[F].capture(s"Get a user id: ${id}") | |
| } | |
| private val user1: Try[String] = getUser[Try]("123") | |
| private val user2: Option[String] = getUser[Option]("123") | |
| private val user3: Either[Error, String] = getUser[Either[Error, ?]]("123") | |
| private val user4: Future[String] = getUser[Future]("123") | |
| private val user5: Future[Try[String]] = getUser[λ[α => Future[Try[α]]]]("123") | |
| private val user6: Future[Option[String]] = getUser[λ[α => Future[Option[α]]]]("123") | |
| private val user7: Future[Either[Error, String]] = getUser[λ[α => Future[Either[Error, α]]]]("123") | |
| } |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment