CoflatMap Instance for Applicative

core/src/main/scala/cats/Applicative.scala

@@ -207,6 +207,28 @@ object Applicative {
  */
  implicit def catsApplicativeForArrow[F[_, _], A](implicit F: Arrow[F]): Applicative[F[A, ?]] =
  new ArrowApplicative[F, A](F)
+
+
+ /**
+ * Creates a CoflatMap for an Applicative `F`.
+ * Cannot be implicit in 1.0 for Binary Compatibility Reasons
+ *
+ * Example:
+ * {{{
+ * scala> import cats._
+ * scala> import cats.implicits._
+ * scala> val fa = Some(3)
+ * fa: Option[Int] = Some(3)
+ * scala> Applicative.coflatMap[Option].coflatten(fa)
+ * res0: Option[Option[Int]] = Some(Some(3))
+ * }}}
+ */
+ def coflatMap[F[_]](implicit F: Applicative[F]): CoflatMap[F] =
+ new CoflatMap[F] {
+ def coflatMap[A, B](fa: F[A])(f: F[A] => B): F[B] = F.pure(f(fa))
+ def map[A, B](fa: F[A])(f: A => B): F[B] = F.map(fa)(f)
+ }
+
 }
 
 private[cats] class ApplicativeMonoid[F[_], A](f: Applicative[F], monoid: Monoid[A]) extends ApplySemigroup(f, monoid) with Monoid[F[A]] {

tests/src/test/scala/cats/tests/ApplicativeSuite.scala

@@ -2,6 +2,9 @@ package cats
 package tests
 
 import cats.Applicative
+import cats.data.{Validated, Const}
+import cats.laws.discipline.arbitrary._
+import cats.laws.discipline.CoflatMapTests
 
 
 class ApplicativeSuite extends CatsSuite {
@@ -36,4 +39,14 @@ class ApplicativeSuite extends CatsSuite {
  }
  }
 
+ implicit val listwrapperApplicative = ListWrapper.applicative
+ implicit val listwrapperCoflatMap = Applicative.coflatMap[ListWrapper]
+ checkAll("Applicative[ListWrapper].coflatMap", CoflatMapTests[ListWrapper].coflatMap[String, String, String])
+
+ implicit val validatedCoflatMap = Applicative.coflatMap[Validated[String, ?]]
+ checkAll("Applicative[Validated].coflatMap", CoflatMapTests[Validated[String, ?]].coflatMap[String, String, String])
+
+ implicit val constCoflatMap = Applicative.coflatMap[Const[String, ?]]
+ checkAll("Applicative[Const].coflatMap", CoflatMapTests[Const[String, ?]].coflatMap[String, String, String])
+
 }