Add Encode and Decode instances to Identity (#50)

bower.json

@@ -22,7 +22,8 @@
     "purescript-ordered-collections": "^1.0.0",
     "purescript-proxy": "^3.0.0",
     "purescript-exceptions": "^4.0.0",
-    "purescript-record": "^1.0.0"
+    "purescript-record": "^1.0.0",
+    "purescript-identity": "^4.1.0"
   },
   "devDependencies": {
     "purescript-assert": "^4.0.0",

src/Foreign/Class.purs

@@ -6,7 +6,9 @@ import Control.Monad.Except (except, mapExcept)
 import Data.Array ((..), zipWith, length)
 import Data.Bifunctor (lmap)
 import Data.Either (Either(..))
+import Data.Identity (Identity(..))
 import Data.Maybe (Maybe, maybe)
+import Data.Newtype (unwrap)
 import Data.Traversable (sequence)
 import Foreign (F, Foreign, ForeignError(..), readArray, readBoolean, readChar, readInt, readNumber, readString, unsafeToForeign)
 import Foreign.Internal (readObject)
@@ -56,6 +58,9 @@ instance numberDecode :: Decode Number where
 instance intDecode :: Decode Int where
   decode = readInt
 
+instance identityDecode :: Decode a => Decode (Identity a) where
+  decode = map Identity <<< decode
+
 instance arrayDecode :: Decode a => Decode (Array a) where
   decode = readArray >=> readElements where
     readElements :: Array Foreign -> F (Array a)
@@ -112,6 +117,9 @@ instance numberEncode :: Encode Number where
 instance intEncode :: Encode Int where
   encode = unsafeToForeign
 
+instance identityEncode :: Encode a => Encode (Identity a) where
+  encode = encode <<< unwrap
+
 instance arrayEncode :: Encode a => Encode (Array a) where
   encode = unsafeToForeign <<< map encode