raiseOrPure (#1933)

typelevel · Sep 26, 2017 · 9123be0 · 9123be0
1 parent dc8637d
commit 9123be0
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diff --git a/core/src/main/scala/cats/syntax/either.scala b/core/src/main/scala/cats/syntax/either.scala
@@ -263,6 +263,10 @@ final class EitherOps[A, B](val eab: Either[A, B]) extends AnyVal {
    * }}}
    */
   def toEitherT[F[_]: Applicative]: EitherT[F, A, B] = EitherT.fromEither(eab)
+
+  def raiseOrPure[F[_]](implicit ev: ApplicativeError[F, A]): F[B] =
+    ev.fromEither(eab)
+
 }
 
 final class EitherObjectOps(val either: Either.type) extends AnyVal { // scalastyle:off ensure.single.space.after.token

diff --git a/tests/src/test/scala/cats/tests/EitherTests.scala b/tests/src/test/scala/cats/tests/EitherTests.scala
@@ -1,7 +1,7 @@
 package cats
 package tests
 
-import cats.data.EitherT
+import cats.data.{ EitherT, Validated }
 import cats.laws.discipline._
 import cats.kernel.laws.{GroupLaws, OrderLaws}
 import scala.util.Try
@@ -276,4 +276,11 @@ class EitherTests extends CatsSuite {
     }
   }
 
+  test("raiseOrPure syntax consistent with fromEither") {
+    val ev = ApplicativeError[Validated[String, ?], String]
+    forAll { (fa: Either[String, Int]) =>
+      fa.raiseOrPure[Validated[String, ?]] should === (ev.fromEither(fa))
+    }
+  }
+
 }