Merge pull request #54 from ajnsit/identityInstances

Add encode/decode instances for `Identity a`

Author: thomashoneyman

bower.json

@@ -29,7 +29,8 @@
     "purescript-foreign-object": "^2.0.0",
     "purescript-record": "^2.0.0",
     "purescript-nonempty": "^5.0.0",
-    "purescript-arrays": "^5.1.0"
+    "purescript-arrays": "^5.1.0",
+    "purescript-identity": "^4.1.0"
   },
   "devDependencies": {
     "purescript-assert": "^4.1.0",

src/Data/Argonaut/Decode/Class.purs

@@ -6,6 +6,7 @@ import Data.Argonaut.Core (Json, isNull, caseJsonNull, caseJsonBoolean, caseJson
 import Data.Array as Arr
 import Data.Bifunctor (lmap, rmap)
 import Data.Either (Either(..), note)
+import Data.Identity (Identity(..))
 import Data.Int (fromNumber)
 import Data.List (List(..), (:), fromFoldable)
 import Data.List as L
@@ -27,6 +28,9 @@ import Type.Data.RowList (RLProxy(..))
 class DecodeJson a where
   decodeJson :: Json -> Either String a
 
+instance decodeIdentity :: DecodeJson a => DecodeJson (Identity a) where
+  decodeJson j = Identity <$> decodeJson j
+
 instance decodeJsonMaybe :: DecodeJson a => DecodeJson (Maybe a) where
   decodeJson j
     | isNull j = pure Nothing

src/Data/Argonaut/Encode/Class.purs

@@ -5,6 +5,7 @@ import Prelude
 import Data.Argonaut.Core (Json, fromArray, fromBoolean, fromNumber, fromObject, fromString, jsonNull)
 import Data.Array as Arr
 import Data.Either (Either, either)
+import Data.Identity (Identity(..))
 import Data.Int (toNumber)
 import Data.List (List(..), (:), toUnfoldable)
 import Data.List as L
@@ -26,6 +27,9 @@ import Type.Data.RowList (RLProxy(..))
 class EncodeJson a where
   encodeJson :: a -> Json
 
+instance encodeIdentity :: EncodeJson a => EncodeJson (Identity a) where
+  encodeJson (Identity a) = encodeJson a
+
 instance encodeJsonMaybe :: EncodeJson a => EncodeJson (Maybe a) where
   encodeJson Nothing  = jsonNull
   encodeJson (Just a) = encodeJson a