add instance for Star (#28)

* add instance for Star

* add Costar instance

Co-authored-by: JordanMartinez <[email protected]>

Author: safareli

bower.json

@@ -23,6 +23,7 @@
     "purescript-maybe": "master",
     "purescript-newtype": "master",
     "purescript-prelude": "master",
+    "purescript-profunctor": "master",
     "purescript-refs": "master",
     "purescript-transformers": "master"
   },

src/Control/Parallel/Class.purs

@@ -14,6 +14,8 @@ import Data.Either (Either)
 import Data.Functor.Compose (Compose(..))
 import Data.Maybe (Maybe(..))
 import Data.Newtype (class Newtype)
+import Data.Profunctor.Costar (Costar(..))
+import Data.Profunctor.Star (Star(..))
 import Effect.Class (class MonadEffect, liftEffect)
 import Effect.Ref as Ref
 
@@ -39,6 +41,15 @@ instance monadParMaybeT :: Parallel f m => Parallel (Compose f Maybe) (MaybeT m)
   parallel (MaybeT ma) = Compose (parallel ma)
   sequential (Compose fa) = MaybeT (sequential fa)
 
+instance monadParStar :: Parallel f m => Parallel (Star f a) (Star m a) where
+  parallel (Star f) = (Star $ parallel <<< f)
+  sequential (Star f) = (Star $ sequential <<< f)
+
+instance monadParCostar :: Parallel f m => Parallel (Costar f a) (Costar m a) where
+  parallel (Costar f) = (Costar $ sequential >>> f)
+  sequential (Costar f) = (Costar $ parallel >>> f)
+
+
 -- | The `ParCont` type constructor provides an `Applicative` instance
 -- | based on `ContT Unit m`, which waits for multiple continuations to be
 -- | resumed simultaneously.