Data.Aeson.Extra.CollapsedList

Documentation

newtype CollapsedList f a

Collapsed list, singleton is represented as the value itself in JSON encoding.

λ > decode "null" :: Maybe (CollapsedList [Int] Int)
Just (CollapsedList [])
λ > decode "42" :: Maybe (CollapsedList [Int] Int)
Just (CollapsedList [42])
λ > decode "[1, 2, 3]" :: Maybe (CollapsedList [Int] Int)
Just (CollapsedList [1,2,3])

λ > encode (CollapsedList ([] :: [Int]))
"null"
λ > encode (CollapsedList ([42] :: [Int]))
"42"
λ > encode (CollapsedList ([1, 2, 3] :: [Int]))
"[1,2,3]"

Documentation rely on f Alternative instance behaving like lists'.

Constructors

CollapsedList (f a)

Instances

Functor f => Functor (CollapsedList f)

Defined in Data.Aeson.Extra.CollapsedList

Methods

fmap :: (a -> b) -> CollapsedList f a -> CollapsedList f b

(<$) :: a -> CollapsedList f b -> CollapsedList f a

Foldable f => Foldable (CollapsedList f)

Defined in Data.Aeson.Extra.CollapsedList

Methods

fold :: Monoid m => CollapsedList f m -> m

foldMap :: Monoid m => (a -> m) -> CollapsedList f a -> m

foldMap' :: Monoid m => (a -> m) -> CollapsedList f a -> m

foldr :: (a -> b -> b) -> b -> CollapsedList f a -> b

foldr' :: (a -> b -> b) -> b -> CollapsedList f a -> b

foldl :: (b -> a -> b) -> b -> CollapsedList f a -> b

foldl' :: (b -> a -> b) -> b -> CollapsedList f a -> b

foldr1 :: (a -> a -> a) -> CollapsedList f a -> a

foldl1 :: (a -> a -> a) -> CollapsedList f a -> a

toList :: CollapsedList f a -> [a]

null :: CollapsedList f a -> Bool

length :: CollapsedList f a -> Int

elem :: Eq a => a -> CollapsedList f a -> Bool

maximum :: Ord a => CollapsedList f a -> a

minimum :: Ord a => CollapsedList f a -> a

sum :: Num a => CollapsedList f a -> a

product :: Num a => CollapsedList f a -> a

Traversable f => Traversable (CollapsedList f)

Defined in Data.Aeson.Extra.CollapsedList

Methods

traverse :: Applicative f0 => (a -> f0 b) -> CollapsedList f a -> f0 (CollapsedList f b)

sequenceA :: Applicative f0 => CollapsedList f (f0 a) -> f0 (CollapsedList f a)

mapM :: Monad m => (a -> m b) -> CollapsedList f a -> m (CollapsedList f b)

sequence :: Monad m => CollapsedList f (m a) -> m (CollapsedList f a)

(ToJSON1 f, Foldable f) => ToJSON1 (CollapsedList f)

Defined in Data.Aeson.Extra.CollapsedList

Methods

liftToJSON :: (a -> Value) -> ([a] -> Value) -> CollapsedList f a -> Value

liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [CollapsedList f a] -> Value

liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> CollapsedList f a -> Encoding

liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [CollapsedList f a] -> Encoding

(FromJSON1 f, Alternative f) => FromJSON1 (CollapsedList f)

Defined in Data.Aeson.Extra.CollapsedList

Methods

liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (CollapsedList f a)

liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [CollapsedList f a]

Eq (f a) => Eq (CollapsedList f a)

Defined in Data.Aeson.Extra.CollapsedList

Methods

(==) :: CollapsedList f a -> CollapsedList f a -> Bool

(/=) :: CollapsedList f a -> CollapsedList f a -> Bool

Ord (f a) => Ord (CollapsedList f a)

Defined in Data.Aeson.Extra.CollapsedList

Methods

compare :: CollapsedList f a -> CollapsedList f a -> Ordering

(<) :: CollapsedList f a -> CollapsedList f a -> Bool

(<=) :: CollapsedList f a -> CollapsedList f a -> Bool

(>) :: CollapsedList f a -> CollapsedList f a -> Bool

(>=) :: CollapsedList f a -> CollapsedList f a -> Bool

max :: CollapsedList f a -> CollapsedList f a -> CollapsedList f a

min :: CollapsedList f a -> CollapsedList f a -> CollapsedList f a

Read (f a) => Read (CollapsedList f a)

Defined in Data.Aeson.Extra.CollapsedList

Methods

readsPrec :: Int -> ReadS (CollapsedList f a)

readList :: ReadS [CollapsedList f a]

readPrec :: ReadPrec (CollapsedList f a)

readListPrec :: ReadPrec [CollapsedList f a]

Show (f a) => Show (CollapsedList f a)

Defined in Data.Aeson.Extra.CollapsedList

Methods

showsPrec :: Int -> CollapsedList f a -> ShowS

show :: CollapsedList f a -> String

showList :: [CollapsedList f a] -> ShowS

(ToJSON1 f, Foldable f, ToJSON a) => ToJSON (CollapsedList f a)

Defined in Data.Aeson.Extra.CollapsedList

Methods

toJSON :: CollapsedList f a -> Value

toEncoding :: CollapsedList f a -> Encoding

toJSONList :: [CollapsedList f a] -> Value

toEncodingList :: [CollapsedList f a] -> Encoding

(FromJSON1 f, Alternative f, FromJSON a) => FromJSON (CollapsedList f a)

Defined in Data.Aeson.Extra.CollapsedList

Methods

parseJSON :: Value -> Parser (CollapsedList f a)

parseJSONList :: Value -> Parser [CollapsedList f a]

getCollapsedList :: CollapsedList f a -> f a

parseCollapsedList :: (FromJSON a, FromJSON1 f, Alternative f) => Object -> Text -> Parser (f a)

Parses possibly collapsed array value from the object's field.

λ > newtype V = V [Int] deriving (Show)
λ > instance FromJSON V where parseJSON = withObject "V" $ \obj -> V <$> parseCollapsedList obj "value"
λ > decode "{}" :: Maybe V
Just (V [])
λ > decode "{\"value\": null}" :: Maybe V
Just (V [])
λ > decode "{\"value\": 42}" :: Maybe V
Just (V [42])
λ > decode "{\"value\": [1, 2, 3, 4]}" :: Maybe V
Just (V [1,2,3,4])