Add attemptTap example

typelevel · Jun 16, 2020 · 6b462db · 6b462db
1 parent 00651a7
commit 6b462db
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Showing 2 changed files with 14 additions and 5 deletions.
diff --git a/core/src/main/scala/cats/MonadError.scala b/core/src/main/scala/cats/MonadError.scala
@@ -88,17 +88,23 @@ trait MonadError[F[_], E] extends ApplicativeError[F, E] with Monad[F] {
  * scala> import cats.implicits._
  * scala> import scala.util.{Try, Success}
  *
- * scala> def logErrors(result: Either[Throwable, Int]): Try[Unit] =
- *
- * scala> val a: Try[Either[Throwable, Int]] = Success(Left(new java.lang.Exception))
+ * scala> def logErrors(result: Either[Throwable, Int]): Try[Unit] = Try {
+ * result match {
+ * case Right(value) => println(s"Success: $value")
+ * case Left(_) => println("Failed")
+ * }
+ * }
+ *
+ * scala> val a: Try[Int] = Success(new java.lang.Exception)
  * scala> a.attemptTap(logErrors)
+ * Failed
  * res0: scala.util.Try[Int] = Failure(java.lang.Exception)
  *
- * scala> val b: Try[Either[Throwable, Int]] = Success(Right(1))
+ * scala> val b: Try[Int] = Success(1)
  * scala> b.attemptTap(logErrors)
+ * Success: 1
  * res1: scala.util.Try[Int] = Success(1)
  * }}}
- *
  */
  def attemptTap[A, B](fa: F[A])(f: Either[E, A] => F[B]): F[A] =
  rethrow(flatTap(attempt(fa))(f))

diff --git a/core/src/main/scala/cats/syntax/monadError.scala b/core/src/main/scala/cats/syntax/monadError.scala
@@ -32,6 +32,9 @@ final class MonadErrorOps[F[_], E, A](private val fa: F[A]) extends AnyVal {
 
  def redeemWith[B](recover: E => F[B], bind: A => F[B])(implicit F: MonadError[F, E]): F[B] =
  F.redeemWith[A, B](fa)(recover, bind)
+
+ def attemptTap[B](f: Either[E, A] => F[B])(implicit F: MonadError[F, E]): F[A] =
+ F.attemptTap(fa)(f)
 }
 
 final class MonadErrorRethrowOps[F[_], E, A](private val fea: F[Either[E, A]]) extends AnyVal {