(co)representable profunctor composition

Data/Profunctor/Corepresentable.hs

@@ -4,9 +4,12 @@ module Data.Profunctor.Corepresentable
   ( CorepresentableProfunctor(..) 
   ) where
 
+import Data.Functor
+import Data.Functor.Identity
 import Data.Profunctor
 import Control.Arrow
-import Data.Functor.Identity
+import qualified Data.Profunctor.Composition as Profunctor
+import qualified Data.Functor.Compose as Functor
 
 class Functor (Corep k) => CorepresentableProfunctor k where
   type Corep k :: * -> *
@@ -27,3 +30,8 @@ instance Functor f => CorepresentableProfunctor (UpStar f) where
   type Corep (UpStar f) = f
   cotabulatePro = UpStar
   coindexPro = runUpStar
+
+instance (CorepresentableProfunctor c, CorepresentableProfunctor d) => CorepresentableProfunctor (Profunctor.Compose c d) where
+  type Corep (Profunctor.Compose c d) = Functor.Compose (Corep c) (Corep d)
+  cotabulatePro f = Profunctor.Compose (cotabulatePro (Functor.getCompose . f)) (cotabulatePro id)
+  coindexPro (Profunctor.Compose f g) d = Functor.Compose $ coindexPro g <$> coindexPro f d

Data/Profunctor/Representable.hs

@@ -3,9 +3,12 @@ module Data.Profunctor.Representable
   ( RepresentableProfunctor(..) 
   ) where
 
+import Data.Functor
+import Data.Functor.Identity
+import qualified Data.Functor.Compose as Functor
 import Data.Profunctor
+import qualified Data.Profunctor.Composition as Profunctor
 import Control.Comonad
-import Data.Functor.Identity
 
 class Functor (Rep k) => RepresentableProfunctor k where
   type Rep k :: * -> *
@@ -26,3 +29,8 @@ instance Functor f => RepresentableProfunctor (DownStar f) where
   type Rep (DownStar f) = f
   tabulatePro = DownStar
   indexPro = runDownStar
+
+instance (RepresentableProfunctor f, RepresentableProfunctor g) => RepresentableProfunctor (Profunctor.Compose f g) where
+  type Rep (Profunctor.Compose f g) = Functor.Compose (Rep g) (Rep f)
+  tabulatePro f = Profunctor.Compose (tabulatePro id) (tabulatePro (f . Functor.Compose))
+  indexPro (Profunctor.Compose f g) (Functor.Compose d) = indexPro g $ indexPro f <$> d

representable-profunctors.cabal

@@ -1,6 +1,6 @@
 name:          representable-profunctors
 category:      Control, Categories
-version:       0.1.0.2
+version:       0.2.0
 license:       BSD3
 cabal-version: >= 1.6
 license-file:  LICENSE
@@ -22,6 +22,7 @@ library
     base >= 4 && < 5,
     comonad >= 1.1 && < 1.2,
     profunctors >= 0.1.1 && < 0.2,
+    profunctor-extras >= 0.2 && < 0.3,
     transformers >= 0.2.2.0 && < 0.3
 
   exposed-modules: