arrow

Type Members

1. trait Arrow[F[_, _]] extends Category[F] with Strong[F] with Serializable

   

   Must obey the laws defined in cats.laws.ArrowLaws.

2. trait ArrowChoice[F[_, _]] extends Arrow[F] with Choice[F] with Serializable

   

   Must obey the laws defined in cats.laws.ArrowChoiceLaws.

3. trait Category[F[_, _]] extends Compose[F] with Serializable

   

   Must obey the laws defined in cats.laws.CategoryLaws.

4. trait Choice[F[_, _]] extends Category[F] with Serializable

   

5. trait CommutativeArrow[F[_, _]] extends Arrow[F] with Serializable

   

   In a Commutative Arrow F[_, _], the split operation (or ***) is commutative, which means that there is non-interference between the effect of the paired arrows.

   In a Commutative Arrow F[_, _], the split operation (or ***) is commutative, which means that there is non-interference between the effect of the paired arrows.

   Must obey the laws in CommutativeArrowLaws

6. trait Compose[F[_, _]] extends Serializable

   

   Must obey the laws defined in cats.laws.ComposeLaws.

   Must obey the laws defined in cats.laws.ComposeLaws.

   Here's how you can use >>> and <<< Example:

   scala> import cats.implicits._
   scala> val f : Int => Int = (_ + 1)
   scala> val g : Int => Int = (_ * 100)
   scala> (f >>> g)(3)
   res0: Int = 400
   scala> (f <<< g)(3)
   res1: Int = 301

7. trait FunctionK[F[_], G[_]] extends Serializable

   

   FunctionK[F[_], G[_]] is a functor transformation from F to G in the same manner that function A => B is a morphism from values of type A to B.

   FunctionK[F[_], G[_]] is a functor transformation from F to G in the same manner that function A => B is a morphism from values of type A to B. An easy way to create a FunctionK instance is to use the Polymorphic lambdas provided by non/kind-projector v0.9+. E.g.

   val listToOption = λ[FunctionK[List, Option]](_.headOption)

8. trait Profunctor[F[_, _]] extends Serializable

   

   A Profunctor is a Contravariant functor on its first type parameter and a Functor on its second type parameter.

   A Profunctor is a Contravariant functor on its first type parameter and a Functor on its second type parameter.

   Must obey the laws defined in cats.laws.ProfunctorLaws.

9. trait Strong[F[_, _]] extends Profunctor[F] with Serializable

   

   Must obey the laws defined in cats.laws.StrongLaws.