Merge pull request #1 from joneshf/master

Added `Choice` and `Strong`.

Author: garyb

README.md

@@ -17,4 +17,32 @@
 
     lmap :: forall a b c p. (Profunctor p) => (a -> b) -> p b c -> p a c
 
-    rmap :: forall a b c p. (Profunctor p) => (b -> c) -> p a b -> p a c
+    rmap :: forall a b c p. (Profunctor p) => (b -> c) -> p a b -> p a c
+
+
+## Module Data.Profunctor.Choice
+
+### Type Classes
+
+    class (Profunctor p) <= Choice p where
+      left :: forall a b c. p a b -> p (Either a c) (Either b c)
+      right :: forall a b c. p b c -> p (Either a b) (Either a c)
+
+
+### Type Class Instances
+
+    instance choiceArr :: Choice Prim.Function
+
+
+## Module Data.Profunctor.Strong
+
+### Type Classes
+
+    class (Profunctor p) <= Strong p where
+      first :: forall a b c. p a b -> p (Tuple a c) (Tuple b c)
+      second :: forall a b c. p b c -> p (Tuple a b) (Tuple a c)
+
+
+### Type Class Instances
+
+    instance strongArr :: Strong Prim.Function

bower.json

@@ -19,5 +19,9 @@
     "bower.json",
     "Gruntfile.js",
     "package.json"
-  ]
+  ],
+  "dependencies": {
+    "purescript-either": "~0.1.4",
+    "purescript-tuples": "~0.2.2"
+  }
 }

src/Data/Profunctor/Choice.purs

@@ -0,0 +1,14 @@
+module Data.Profunctor.Choice where
+
+  import Data.Either (Either(..))
+  import Data.Profunctor (Profunctor)
+
+  class (Profunctor p) <= Choice p where
+    left :: forall a b c. p a b -> p (Either a c) (Either b c)
+    right :: forall a b c. p b c -> p (Either a b) (Either a c)
+
+  instance choiceArr :: Choice (->) where
+    left a2b (Left a)  = Left $ a2b a
+    left _   (Right c) = Right c
+
+    right = (<$>)

src/Data/Profunctor/Strong.purs

@@ -0,0 +1,12 @@
+module Data.Profunctor.Strong where
+
+  import Data.Profunctor (Profunctor)
+  import Data.Tuple (Tuple(..))
+
+  class (Profunctor p) <= Strong p where
+    first :: forall a b c. p a b -> p (Tuple a c) (Tuple b c)
+    second :: forall a b c. p b c -> p (Tuple a b) (Tuple a c)
+
+  instance strongArr :: Strong (->) where
+    first a2b (Tuple a c) = Tuple (a2b a) c
+    second = (<$>)