Add decoders for Char

Author: i-am-the-slime

src/Data/Argonaut/Decode/Class.purs

@@ -76,6 +76,9 @@ instance decodeJsonNonEmptyList :: (DecodeJson a) => DecodeJson (NonEmptyList a)
 instance decodeJsonCodePoint :: DecodeJson CodePoint where
   decodeJson = decodeCodePoint
 
+instance decodeChar :: DecodeJson Char where
+  decodeJson = decodeChar
+
 instance decodeForeignObject :: DecodeJson a => DecodeJson (FO.Object a) where
   decodeJson = decodeForeignObject decodeJson
 

src/Data/Argonaut/Decode/Decoders.purs

@@ -26,6 +26,7 @@ import Data.Traversable (traverse)
 import Data.TraversableWithIndex (traverseWithIndex)
 import Data.Tuple (Tuple(..))
 import Foreign.Object as FO
+import Data.String.CodeUnits (toChar) as CU
 
 decodeIdentity
   :: forall a
@@ -148,6 +149,11 @@ decodeCodePoint json =
   note (Named "CodePoint" $ UnexpectedValue json)
     =<< map (codePointAt 0) (decodeString json)
 
+decodeChar :: Json -> Either JsonDecodeError Char
+decodeChar json =
+  note (Named "Char" $ UnexpectedValue json)
+    =<< map CU.toChar (decodeString json)
+
 decodeForeignObject
   :: forall a
    . (Json -> Either JsonDecodeError a)

test/Test/Main.purs

@@ -71,6 +71,7 @@ jsonParser' = either (liftEffect <<< throw) pure <<< jsonParser
 main :: Effect Unit
 main = flip runReaderT 0 do
   suite "Either Check" eitherCheck
+  suite "Char Check" charCheck
   suite "Encode/Decode NonEmpty Check" nonEmptyCheck
   suite "Encode/Decode Checks" encodeDecodeCheck
   suite "Encode/Decode Record Checks" encodeDecodeRecordCheck
@@ -222,6 +223,17 @@ eitherCheck = do
         Left err ->
           false <?> printJsonDecodeError err
 
+charCheck :: Test
+charCheck = do
+  test "Test EncodeJson/DecodeJson Char test" do
+    quickCheck \(x :: Char) ->
+      case decodeJson (encodeJson x) of
+        Right decoded ->
+          decoded == x
+            <?> ("x = " <> show x <> ", decoded = " <> show decoded)
+        Left err ->
+          false <?> printJsonDecodeError err
+
 manualRecordDecode :: Test
 manualRecordDecode = do
   fooJson <- jsonParser' """{ "bar": [1, 2, 3], "baz": true }"""