splitStrong/Choice with Semigroupoid instead of Category constrain (#48)

* splitStrong/Choice with Semigroupoing not a Category

* changelog

CHANGELOG.md

@@ -9,6 +9,7 @@ Breaking changes:
 New features:
 
 Bugfixes:
+- `splitStrong` and `splitChoice` functions as not requiring `identity` have now relaxed constrain of `Semigroupoid` instead of `Catergory`.  
 
 Other improvements:
 

src/Data/Profunctor/Choice.purs

@@ -3,7 +3,7 @@ module Data.Profunctor.Choice where
 import Prelude
 
 import Data.Either (Either(..), either)
-import Data.Profunctor (class Profunctor, dimap)
+import Data.Profunctor (class Profunctor, rmap)
 
 -- | The `Choice` class extends `Profunctor` with combinators for working with
 -- | sum types.
@@ -46,7 +46,7 @@ instance choiceFn :: Choice (->) where
 -- | `bi-map` would do for the `bi-functor` instance of `Either`.
 splitChoice
   :: forall p a b c d
-   . Category p
+   . Semigroupoid p
   => Choice p
   => p a b
   -> p c d
@@ -73,14 +73,11 @@ infixr 2 splitChoice as +++
 -- | function which will run the approriate computation based on the parameter supplied in the `Either` value.
 fanin
   :: forall p a b c
-   . Category p
+   . Semigroupoid p
   => Choice p
   => p a c
   -> p b c
   -> p (Either a b) c
-fanin l r = (l +++ r) >>> join
-  where
-  join :: p (Either c c) c
-  join = dimap (either identity identity) identity identity
+fanin l r = rmap (either identity identity) (l +++ r)
 
 infixr 2 fanin as |||

src/Data/Profunctor/Strong.purs

@@ -2,7 +2,7 @@ module Data.Profunctor.Strong where
 
 import Prelude
 
-import Data.Profunctor (class Profunctor, dimap)
+import Data.Profunctor (class Profunctor, lcmap)
 import Data.Tuple (Tuple(..))
 
 -- | The `Strong` class extends `Profunctor` with combinators for working with
@@ -45,7 +45,7 @@ instance strongFn :: Strong (->) where
 -- | would do for the `bi-functor` instance of `Tuple`.
 splitStrong
   :: forall p a b c d
-   . Category p
+   . Semigroupoid p
   => Strong p
   => p a b
   -> p c d
@@ -70,14 +70,11 @@ infixr 3 splitStrong as ***
 -- | on the same input and return both results in a `Tuple`.
 fanout
   :: forall p a b c
-   . Category p
+   . Semigroupoid p
   => Strong p
   => p a b
   -> p a c
   -> p a (Tuple b c)
-fanout l r = split >>> (l *** r)
-  where
-  split :: p a (Tuple a a)
-  split = dimap identity (\a -> Tuple a a) identity
+fanout l r = lcmap (\a -> Tuple a a) (l *** r)
 
 infixr 3 fanout as &&&