Safe Haskell	Safe-Inferred
Language	Haskell2010

Generics.SOP.JSON

Contents

Configuration
JSON view of a datatype
Generic functions
UpdateFromJSON and co
Re-exports

Synopsis

type JsonFieldName = String
type JsonTagName = String
data JsonOptions = JsonOptions {
- jsonFieldName :: DatatypeName -> FieldName -> JsonFieldName
- jsonTagName :: ConstructorName -> JsonTagName
}
defaultJsonOptions :: JsonOptions
data Tag
- = NoTag
- | Tag JsonTagName
data JsonInfo :: [Type] -> Type where
- JsonZero :: ConstructorName -> JsonInfo '[]
- JsonOne :: Tag -> JsonInfo '[a]
- JsonMultiple :: SListI xs => Tag -> JsonInfo xs
- JsonRecord :: SListI xs => Tag -> NP (K String) xs -> JsonInfo xs
jsonInfo :: forall a. (HasDatatypeInfo a, SListI (Code a)) => Proxy a -> JsonOptions -> NP JsonInfo (Code a)
gtoJSON :: forall a. (Generic a, HasDatatypeInfo a, All2 ToJSON (Code a)) => JsonOptions -> a -> Value
gparseJSON :: forall a. (Generic a, HasDatatypeInfo a, All2 FromJSON (Code a)) => JsonOptions -> Value -> Parser a
class UpdateFromJSON a where
- updateFromJSON :: Value -> Parser (a -> a)
gupdateFromJSON :: forall a xs. (Generic a, HasDatatypeInfo a, All UpdateFromJSON xs, Code a ~ '[xs]) => JsonOptions -> Value -> Parser (a -> a)
replaceWithJSON :: FromJSON a => Value -> Parser (a -> a)
parseWith :: UpdateFromJSON a => a -> Value -> Parser a
class ToJSON a where
- toJSON :: a -> Value
- toEncoding :: a -> Encoding
- toJSONList :: [a] -> Value
- toEncodingList :: [a] -> Encoding
- omitField :: a -> Bool
class FromJSON a where
- parseJSON :: Value -> Parser a
- parseJSONList :: Value -> Parser [a]
- omittedField :: Maybe a
data Proxy (t :: k) = Proxy

Configuration

type JsonFieldName = String Source #

type JsonTagName = String Source #

data JsonOptions Source #

JSON encoder/decoder configuration

Constructors

JsonOptions
Fields jsonFieldName :: DatatypeName -> FieldName -> JsonFieldName Construct the name for JSON object fields (not for the tags that are used for sum-types, however) The default just uses the name of the corresponding Haskell constructor jsonTagName :: ConstructorName -> JsonTagName Construct the name for a tag for sum-types. The default just uses the name of the Haskell constructor.

defaultJsonOptions :: JsonOptions Source #

JSON view of a datatype

data Tag Source #

Constructor tag

For a datatype with a single constructor we do not need to tag values with their constructor; but for a datatype with multiple constructors we do.

Constructors

NoTag
Tag JsonTagName

data JsonInfo :: [Type] -> Type where Source #

Constructors

JsonZero :: ConstructorName -> JsonInfo '[]
JsonOne :: Tag -> JsonInfo '[a]
JsonMultiple :: SListI xs => Tag -> JsonInfo xs
JsonRecord :: SListI xs => Tag -> NP (K String) xs -> JsonInfo xs

jsonInfo :: forall a. (HasDatatypeInfo a, SListI (Code a)) => Proxy a -> JsonOptions -> NP JsonInfo (Code a) Source #

Generic functions

gtoJSON :: forall a. (Generic a, HasDatatypeInfo a, All2 ToJSON (Code a)) => JsonOptions -> a -> Value Source #

gparseJSON :: forall a. (Generic a, HasDatatypeInfo a, All2 FromJSON (Code a)) => JsonOptions -> Value -> Parser a Source #

UpdateFromJSON and co

class UpdateFromJSON a where Source #

For some values we can support "updating" the value with a "partial" JSON value; record types are the prime example (and the only one supported by the generic function). For non-record types we typically can only replace the value with a "complete" JSON value; in this case, we simply ignore the old value (see replaceWithJSON). Typical class instances will look like

instance UpdateFromJSON SomeRecordType where
   updateFromJSON = gupdateFromJSON <jsonOptions>

or

instance UpdateFromJSON SomeNonRecordType where
   updateFromJSON = replaceWithJSON

NOTE: The generic function uses one-level lenses for the object fields. We could generalize this to arbitrary paths, but then the type would change to

updateFromJSON :: Value -> Parser (a -> UpdateM a)

I.e., updating a value from JSON would, in general, involve a database write.

Methods

updateFromJSON :: Value -> Parser (a -> a) Source #

Instances

Instances details

UpdateFromJSON Rational Source #
Instance details Defined in Generics.SOP.JSON Methods updateFromJSON :: Value -> Parser (Rational -> Rational) Source #
UpdateFromJSON Text Source #
Instance details Defined in Generics.SOP.JSON Methods updateFromJSON :: Value -> Parser (Text -> Text) Source #
UpdateFromJSON String Source #
Instance details Defined in Generics.SOP.JSON Methods updateFromJSON :: Value -> Parser (String -> String) Source #
UpdateFromJSON Bool Source #
Instance details Defined in Generics.SOP.JSON Methods updateFromJSON :: Value -> Parser (Bool -> Bool) Source #
UpdateFromJSON Double Source #
Instance details Defined in Generics.SOP.JSON Methods updateFromJSON :: Value -> Parser (Double -> Double) Source #
UpdateFromJSON Int Source #
Instance details Defined in Generics.SOP.JSON Methods updateFromJSON :: Value -> Parser (Int -> Int) Source #
FromJSON a => UpdateFromJSON (Maybe a) Source #
Instance details Defined in Generics.SOP.JSON Methods updateFromJSON :: Value -> Parser (Maybe a -> Maybe a) Source #
FromJSON a => UpdateFromJSON [a] Source #
Instance details Defined in Generics.SOP.JSON Methods updateFromJSON :: Value -> Parser ([a] -> [a]) Source #

gupdateFromJSON :: forall a xs. (Generic a, HasDatatypeInfo a, All UpdateFromJSON xs, Code a ~ '[xs]) => JsonOptions -> Value -> Parser (a -> a) Source #

Construct a function that updates a value of some record type, given a JSON object with new values for some (or none, or all) of the fields

replaceWithJSON :: FromJSON a => Value -> Parser (a -> a) Source #

For types that we can only replace "whole", rather than update field by field

parseWith :: UpdateFromJSON a => a -> Value -> Parser a Source #

Conversely, for types that we can only parse if we have a starting point

Re-exports

class ToJSON a where #

A type that can be converted to JSON.

Instances in general must specify toJSON and should (but don't need to) specify toEncoding.

An example type and instance:

-- Allow ourselves to write Text literals.
{-# LANGUAGE OverloadedStrings #-}

data Coord = Coord { x :: Double, y :: Double }

instance ToJSON Coord where
  toJSON (Coord x y) = object ["x" .= x, "y" .= y]

  toEncoding (Coord x y) = pairs ("x" .= x <> "y" .= y)

Instead of manually writing your ToJSON instance, there are two options to do it automatically:

Data.Aeson.TH provides Template Haskell functions which will derive an instance at compile time. The generated instance is optimized for your type so it will probably be more efficient than the following option.
The compiler can provide a default generic implementation for toJSON.

To use the second, simply add a deriving Generic clause to your datatype and declare a ToJSON instance. If you require nothing other than defaultOptions, it is sufficient to write (and this is the only alternative where the default toJSON implementation is sufficient):

{-# LANGUAGE DeriveGeneric #-}

import GHC.Generics

data Coord = Coord { x :: Double, y :: Double } deriving Generic

instance ToJSON Coord where
    toEncoding = genericToEncoding defaultOptions

or more conveniently using the DerivingVia extension

deriving via Generically Coord instance ToJSON Coord

If on the other hand you wish to customize the generic decoding, you have to implement both methods:

customOptions = defaultOptions
                { fieldLabelModifier = map toUpper
                }

instance ToJSON Coord where
    toJSON     = genericToJSON customOptions
    toEncoding = genericToEncoding customOptions

Previous versions of this library only had the toJSON method. Adding toEncoding had two reasons:

toEncoding is more efficient for the common case that the output of toJSON is directly serialized to a ByteString. Further, expressing either method in terms of the other would be non-optimal.
The choice of defaults allows a smooth transition for existing users: Existing instances that do not define toEncoding still compile and have the correct semantics. This is ensured by making the default implementation of toEncoding use toJSON. This produces correct results, but since it performs an intermediate conversion to a Value, it will be less efficient than directly emitting an Encoding. (this also means that specifying nothing more than instance ToJSON Coord would be sufficient as a generically decoding instance, but there probably exists no good reason to not specify toEncoding in new instances.)

Minimal complete definition

Nothing

Methods

toJSON :: a -> Value #

Convert a Haskell value to a JSON-friendly intermediate type.

toEncoding :: a -> Encoding #

Encode a Haskell value as JSON.

The default implementation of this method creates an intermediate Value using toJSON. This provides source-level compatibility for people upgrading from older versions of this library, but obviously offers no performance advantage.

To benefit from direct encoding, you must provide an implementation for this method. The easiest way to do so is by having your types implement Generic using the DeriveGeneric extension, and then have GHC generate a method body as follows.

instance ToJSON Coord where
    toEncoding = genericToEncoding defaultOptions

toJSONList :: [a] -> Value #

toEncodingList :: [a] -> Encoding #

omitField :: a -> Bool #

Defines when it is acceptable to omit a field of this type from a record. Used by (.?=) operator, and Generics and TH deriving with omitNothingFields = True.

Since: aeson-2.2.0.0

Instances

Instances details

ToJSON Key
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Key -> Value # toEncoding :: Key -> Encoding # toJSONList :: [Key] -> Value # toEncodingList :: [Key] -> Encoding # omitField :: Key -> Bool #
ToJSON DotNetTime
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: DotNetTime -> Value # toEncoding :: DotNetTime -> Encoding # toJSONList :: [DotNetTime] -> Value # toEncodingList :: [DotNetTime] -> Encoding # omitField :: DotNetTime -> Bool #
ToJSON Value
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Value -> Value # toEncoding :: Value -> Encoding # toJSONList :: [Value] -> Value # toEncodingList :: [Value] -> Encoding # omitField :: Value -> Bool #
ToJSON All	Since: aeson-2.2.3.0
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: All -> Value # toEncoding :: All -> Encoding # toJSONList :: [All] -> Value # toEncodingList :: [All] -> Encoding # omitField :: All -> Bool #
ToJSON Any	Since: aeson-2.2.3.0
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Any -> Value # toEncoding :: Any -> Encoding # toJSONList :: [Any] -> Value # toEncodingList :: [Any] -> Encoding # omitField :: Any -> Bool #
ToJSON Version
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Version -> Value # toEncoding :: Version -> Encoding # toJSONList :: [Version] -> Value # toEncodingList :: [Version] -> Encoding # omitField :: Version -> Bool #
ToJSON CTime
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: CTime -> Value # toEncoding :: CTime -> Encoding # toJSONList :: [CTime] -> Value # toEncodingList :: [CTime] -> Encoding # omitField :: CTime -> Bool #
ToJSON Void
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Void -> Value # toEncoding :: Void -> Encoding # toJSONList :: [Void] -> Value # toEncodingList :: [Void] -> Encoding # omitField :: Void -> Bool #
ToJSON Int16
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Int16 -> Value # toEncoding :: Int16 -> Encoding # toJSONList :: [Int16] -> Value # toEncodingList :: [Int16] -> Encoding # omitField :: Int16 -> Bool #
ToJSON Int32
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Int32 -> Value # toEncoding :: Int32 -> Encoding # toJSONList :: [Int32] -> Value # toEncodingList :: [Int32] -> Encoding # omitField :: Int32 -> Bool #
ToJSON Int64
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Int64 -> Value # toEncoding :: Int64 -> Encoding # toJSONList :: [Int64] -> Value # toEncodingList :: [Int64] -> Encoding # omitField :: Int64 -> Bool #
ToJSON Int8
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Int8 -> Value # toEncoding :: Int8 -> Encoding # toJSONList :: [Int8] -> Value # toEncodingList :: [Int8] -> Encoding # omitField :: Int8 -> Bool #
ToJSON Word16
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Word16 -> Value # toEncoding :: Word16 -> Encoding # toJSONList :: [Word16] -> Value # toEncodingList :: [Word16] -> Encoding # omitField :: Word16 -> Bool #
ToJSON Word32
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Word32 -> Value # toEncoding :: Word32 -> Encoding # toJSONList :: [Word32] -> Value # toEncodingList :: [Word32] -> Encoding # omitField :: Word32 -> Bool #
ToJSON Word64
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Word64 -> Value # toEncoding :: Word64 -> Encoding # toJSONList :: [Word64] -> Value # toEncodingList :: [Word64] -> Encoding # omitField :: Word64 -> Bool #
ToJSON Word8
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Word8 -> Value # toEncoding :: Word8 -> Encoding # toJSONList :: [Word8] -> Value # toEncodingList :: [Word8] -> Encoding # omitField :: Word8 -> Bool #
ToJSON IntSet
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: IntSet -> Value # toEncoding :: IntSet -> Encoding # toJSONList :: [IntSet] -> Value # toEncodingList :: [IntSet] -> Encoding # omitField :: IntSet -> Bool #
ToJSON Ordering
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Ordering -> Value # toEncoding :: Ordering -> Encoding # toJSONList :: [Ordering] -> Value # toEncodingList :: [Ordering] -> Encoding # omitField :: Ordering -> Bool #
ToJSON URI	Since: aeson-2.2.0.0
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: URI -> Value # toEncoding :: URI -> Encoding # toJSONList :: [URI] -> Value # toEncodingList :: [URI] -> Encoding # omitField :: URI -> Bool #
ToJSON Scientific
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Scientific -> Value # toEncoding :: Scientific -> Encoding # toJSONList :: [Scientific] -> Value # toEncodingList :: [Scientific] -> Encoding # omitField :: Scientific -> Bool #
ToJSON Text
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Text -> Value # toEncoding :: Text -> Encoding # toJSONList :: [Text] -> Value # toEncodingList :: [Text] -> Encoding # omitField :: Text -> Bool #
ToJSON Text
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Text -> Value # toEncoding :: Text -> Encoding # toJSONList :: [Text] -> Value # toEncodingList :: [Text] -> Encoding # omitField :: Text -> Bool #
ToJSON ShortText	Since: aeson-2.0.2.0
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: ShortText -> Value # toEncoding :: ShortText -> Encoding # toJSONList :: [ShortText] -> Value # toEncodingList :: [ShortText] -> Encoding # omitField :: ShortText -> Bool #
ToJSON CalendarDiffDays
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: CalendarDiffDays -> Value # toEncoding :: CalendarDiffDays -> Encoding # toJSONList :: [CalendarDiffDays] -> Value # toEncodingList :: [CalendarDiffDays] -> Encoding # omitField :: CalendarDiffDays -> Bool #
ToJSON Day
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Day -> Value # toEncoding :: Day -> Encoding # toJSONList :: [Day] -> Value # toEncodingList :: [Day] -> Encoding # omitField :: Day -> Bool #
ToJSON Month
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Month -> Value # toEncoding :: Month -> Encoding # toJSONList :: [Month] -> Value # toEncodingList :: [Month] -> Encoding # omitField :: Month -> Bool #
ToJSON Quarter
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Quarter -> Value # toEncoding :: Quarter -> Encoding # toJSONList :: [Quarter] -> Value # toEncodingList :: [Quarter] -> Encoding # omitField :: Quarter -> Bool #
ToJSON QuarterOfYear
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: QuarterOfYear -> Value # toEncoding :: QuarterOfYear -> Encoding # toJSONList :: [QuarterOfYear] -> Value # toEncodingList :: [QuarterOfYear] -> Encoding # omitField :: QuarterOfYear -> Bool #
ToJSON DayOfWeek
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: DayOfWeek -> Value # toEncoding :: DayOfWeek -> Encoding # toJSONList :: [DayOfWeek] -> Value # toEncodingList :: [DayOfWeek] -> Encoding # omitField :: DayOfWeek -> Bool #
ToJSON DiffTime
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: DiffTime -> Value # toEncoding :: DiffTime -> Encoding # toJSONList :: [DiffTime] -> Value # toEncodingList :: [DiffTime] -> Encoding # omitField :: DiffTime -> Bool #
ToJSON NominalDiffTime
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: NominalDiffTime -> Value # toEncoding :: NominalDiffTime -> Encoding # toJSONList :: [NominalDiffTime] -> Value # toEncodingList :: [NominalDiffTime] -> Encoding # omitField :: NominalDiffTime -> Bool #
ToJSON SystemTime	Encoded as number
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: SystemTime -> Value # toEncoding :: SystemTime -> Encoding # toJSONList :: [SystemTime] -> Value # toEncodingList :: [SystemTime] -> Encoding # omitField :: SystemTime -> Bool #
ToJSON UTCTime
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: UTCTime -> Value # toEncoding :: UTCTime -> Encoding # toJSONList :: [UTCTime] -> Value # toEncodingList :: [UTCTime] -> Encoding # omitField :: UTCTime -> Bool #
ToJSON CalendarDiffTime
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: CalendarDiffTime -> Value # toEncoding :: CalendarDiffTime -> Encoding # toJSONList :: [CalendarDiffTime] -> Value # toEncodingList :: [CalendarDiffTime] -> Encoding # omitField :: CalendarDiffTime -> Bool #
ToJSON LocalTime
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: LocalTime -> Value # toEncoding :: LocalTime -> Encoding # toJSONList :: [LocalTime] -> Value # toEncodingList :: [LocalTime] -> Encoding # omitField :: LocalTime -> Bool #
ToJSON TimeOfDay
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: TimeOfDay -> Value # toEncoding :: TimeOfDay -> Encoding # toJSONList :: [TimeOfDay] -> Value # toEncodingList :: [TimeOfDay] -> Encoding # omitField :: TimeOfDay -> Bool #
ToJSON ZonedTime
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: ZonedTime -> Value # toEncoding :: ZonedTime -> Encoding # toJSONList :: [ZonedTime] -> Value # toEncodingList :: [ZonedTime] -> Encoding # omitField :: ZonedTime -> Bool #
ToJSON UUID
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: UUID -> Value # toEncoding :: UUID -> Encoding # toJSONList :: [UUID] -> Value # toEncodingList :: [UUID] -> Encoding # omitField :: UUID -> Bool #
ToJSON Integer
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Integer -> Value # toEncoding :: Integer -> Encoding # toJSONList :: [Integer] -> Value # toEncodingList :: [Integer] -> Encoding # omitField :: Integer -> Bool #
ToJSON Natural
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Natural -> Value # toEncoding :: Natural -> Encoding # toJSONList :: [Natural] -> Value # toEncodingList :: [Natural] -> Encoding # omitField :: Natural -> Bool #
ToJSON ()
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: () -> Value # toEncoding :: () -> Encoding # toJSONList :: [()] -> Value # toEncodingList :: [()] -> Encoding # omitField :: () -> Bool #
ToJSON Bool
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Bool -> Value # toEncoding :: Bool -> Encoding # toJSONList :: [Bool] -> Value # toEncodingList :: [Bool] -> Encoding # omitField :: Bool -> Bool #
ToJSON Char
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Char -> Value # toEncoding :: Char -> Encoding # toJSONList :: [Char] -> Value # toEncodingList :: [Char] -> Encoding # omitField :: Char -> Bool #
ToJSON Double
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Double -> Value # toEncoding :: Double -> Encoding # toJSONList :: [Double] -> Value # toEncodingList :: [Double] -> Encoding # omitField :: Double -> Bool #
ToJSON Float
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Float -> Value # toEncoding :: Float -> Encoding # toJSONList :: [Float] -> Value # toEncodingList :: [Float] -> Encoding # omitField :: Float -> Bool #
ToJSON Int
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Int -> Value # toEncoding :: Int -> Encoding # toJSONList :: [Int] -> Value # toEncodingList :: [Int] -> Encoding # omitField :: Int -> Bool #
ToJSON Word
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Word -> Value # toEncoding :: Word -> Encoding # toJSONList :: [Word] -> Value # toEncodingList :: [Word] -> Encoding # omitField :: Word -> Bool #
ToJSON v => ToJSON (KeyMap v)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: KeyMap v -> Value # toEncoding :: KeyMap v -> Encoding # toJSONList :: [KeyMap v] -> Value # toEncodingList :: [KeyMap v] -> Encoding # omitField :: KeyMap v -> Bool #
ToJSON a => ToJSON (Identity a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Identity a -> Value # toEncoding :: Identity a -> Encoding # toJSONList :: [Identity a] -> Value # toEncodingList :: [Identity a] -> Encoding # omitField :: Identity a -> Bool #
ToJSON a => ToJSON (First a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: First a -> Value # toEncoding :: First a -> Encoding # toJSONList :: [First a] -> Value # toEncodingList :: [First a] -> Encoding # omitField :: First a -> Bool #
ToJSON a => ToJSON (Last a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Last a -> Value # toEncoding :: Last a -> Encoding # toJSONList :: [Last a] -> Value # toEncodingList :: [Last a] -> Encoding # omitField :: Last a -> Bool #
ToJSON a => ToJSON (Down a)	Since: aeson-2.2.0.0
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Down a -> Value # toEncoding :: Down a -> Encoding # toJSONList :: [Down a] -> Value # toEncodingList :: [Down a] -> Encoding # omitField :: Down a -> Bool #
ToJSON a => ToJSON (First a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: First a -> Value # toEncoding :: First a -> Encoding # toJSONList :: [First a] -> Value # toEncodingList :: [First a] -> Encoding # omitField :: First a -> Bool #
ToJSON a => ToJSON (Last a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Last a -> Value # toEncoding :: Last a -> Encoding # toJSONList :: [Last a] -> Value # toEncodingList :: [Last a] -> Encoding # omitField :: Last a -> Bool #
ToJSON a => ToJSON (Max a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Max a -> Value # toEncoding :: Max a -> Encoding # toJSONList :: [Max a] -> Value # toEncodingList :: [Max a] -> Encoding # omitField :: Max a -> Bool #
ToJSON a => ToJSON (Min a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Min a -> Value # toEncoding :: Min a -> Encoding # toJSONList :: [Min a] -> Value # toEncodingList :: [Min a] -> Encoding # omitField :: Min a -> Bool #
ToJSON a => ToJSON (WrappedMonoid a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: WrappedMonoid a -> Value # toEncoding :: WrappedMonoid a -> Encoding # toJSONList :: [WrappedMonoid a] -> Value # toEncodingList :: [WrappedMonoid a] -> Encoding # omitField :: WrappedMonoid a -> Bool #
ToJSON a => ToJSON (Dual a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Dual a -> Value # toEncoding :: Dual a -> Encoding # toJSONList :: [Dual a] -> Value # toEncodingList :: [Dual a] -> Encoding # omitField :: Dual a -> Bool #
ToJSON a => ToJSON (Product a)	Since: aeson-2.2.3.0
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Product a -> Value # toEncoding :: Product a -> Encoding # toJSONList :: [Product a] -> Value # toEncodingList :: [Product a] -> Encoding # omitField :: Product a -> Bool #
ToJSON a => ToJSON (Sum a)	Since: aeson-2.2.3.0
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Sum a -> Value # toEncoding :: Sum a -> Encoding # toJSONList :: [Sum a] -> Value # toEncodingList :: [Sum a] -> Encoding # omitField :: Sum a -> Bool #
ToJSON a => ToJSON (NonEmpty a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: NonEmpty a -> Value # toEncoding :: NonEmpty a -> Encoding # toJSONList :: [NonEmpty a] -> Value # toEncodingList :: [NonEmpty a] -> Encoding # omitField :: NonEmpty a -> Bool #
(Generic a, GToJSON' Value Zero (Rep a), GToJSON' Encoding Zero (Rep a)) => ToJSON (Generically a)	Since: aeson-2.1.0.0
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Generically a -> Value # toEncoding :: Generically a -> Encoding # toJSONList :: [Generically a] -> Value # toEncodingList :: [Generically a] -> Encoding # omitField :: Generically a -> Bool #
(ToJSON a, Integral a) => ToJSON (Ratio a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Ratio a -> Value # toEncoding :: Ratio a -> Encoding # toJSONList :: [Ratio a] -> Value # toEncodingList :: [Ratio a] -> Encoding # omitField :: Ratio a -> Bool #
ToJSON a => ToJSON (IntMap a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: IntMap a -> Value # toEncoding :: IntMap a -> Encoding # toJSONList :: [IntMap a] -> Value # toEncodingList :: [IntMap a] -> Encoding # omitField :: IntMap a -> Bool #
ToJSON a => ToJSON (Seq a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Seq a -> Value # toEncoding :: Seq a -> Encoding # toJSONList :: [Seq a] -> Value # toEncodingList :: [Seq a] -> Encoding # omitField :: Seq a -> Bool #
ToJSON a => ToJSON (Set a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Set a -> Value # toEncoding :: Set a -> Encoding # toJSONList :: [Set a] -> Value # toEncodingList :: [Set a] -> Encoding # omitField :: Set a -> Bool #
ToJSON v => ToJSON (Tree v)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Tree v -> Value # toEncoding :: Tree v -> Encoding # toJSONList :: [Tree v] -> Value # toEncodingList :: [Tree v] -> Encoding # omitField :: Tree v -> Bool #
ToJSON1 f => ToJSON (Fix f)	Since: aeson-1.5.3.0
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Fix f -> Value # toEncoding :: Fix f -> Encoding # toJSONList :: [Fix f] -> Value # toEncodingList :: [Fix f] -> Encoding # omitField :: Fix f -> Bool #
(ToJSON1 f, Functor f) => ToJSON (Mu f)	Since: aeson-1.5.3.0
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Mu f -> Value # toEncoding :: Mu f -> Encoding # toJSONList :: [Mu f] -> Value # toEncodingList :: [Mu f] -> Encoding # omitField :: Mu f -> Bool #
(ToJSON1 f, Functor f) => ToJSON (Nu f)	Since: aeson-1.5.3.0
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Nu f -> Value # toEncoding :: Nu f -> Encoding # toJSONList :: [Nu f] -> Value # toEncodingList :: [Nu f] -> Encoding # omitField :: Nu f -> Bool #
ToJSON a => ToJSON (DNonEmpty a)	Since: aeson-1.5.3.0
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: DNonEmpty a -> Value # toEncoding :: DNonEmpty a -> Encoding # toJSONList :: [DNonEmpty a] -> Value # toEncodingList :: [DNonEmpty a] -> Encoding # omitField :: DNonEmpty a -> Bool #
ToJSON a => ToJSON (DList a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: DList a -> Value # toEncoding :: DList a -> Encoding # toJSONList :: [DList a] -> Value # toEncodingList :: [DList a] -> Encoding # omitField :: DList a -> Bool #
ToJSON a => ToJSON (Array a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Array a -> Value # toEncoding :: Array a -> Encoding # toJSONList :: [Array a] -> Value # toEncodingList :: [Array a] -> Encoding # omitField :: Array a -> Bool #
(Prim a, ToJSON a) => ToJSON (PrimArray a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: PrimArray a -> Value # toEncoding :: PrimArray a -> Encoding # toJSONList :: [PrimArray a] -> Value # toEncodingList :: [PrimArray a] -> Encoding # omitField :: PrimArray a -> Bool #
ToJSON a => ToJSON (SmallArray a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: SmallArray a -> Value # toEncoding :: SmallArray a -> Encoding # toJSONList :: [SmallArray a] -> Value # toEncodingList :: [SmallArray a] -> Encoding # omitField :: SmallArray a -> Bool #
ToJSON a => ToJSON (Maybe a)	Since: aeson-1.5.3.0
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Maybe a -> Value # toEncoding :: Maybe a -> Encoding # toJSONList :: [Maybe a] -> Value # toEncodingList :: [Maybe a] -> Encoding # omitField :: Maybe a -> Bool #
ToJSON a => ToJSON (HashSet a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: HashSet a -> Value # toEncoding :: HashSet a -> Encoding # toJSONList :: [HashSet a] -> Value # toEncodingList :: [HashSet a] -> Encoding # omitField :: HashSet a -> Bool #
ToJSON a => ToJSON (Vector a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Vector a -> Value # toEncoding :: Vector a -> Encoding # toJSONList :: [Vector a] -> Value # toEncodingList :: [Vector a] -> Encoding # omitField :: Vector a -> Bool #
(Prim a, ToJSON a) => ToJSON (Vector a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Vector a -> Value # toEncoding :: Vector a -> Encoding # toJSONList :: [Vector a] -> Value # toEncodingList :: [Vector a] -> Encoding # omitField :: Vector a -> Bool #
(Storable a, ToJSON a) => ToJSON (Vector a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Vector a -> Value # toEncoding :: Vector a -> Encoding # toJSONList :: [Vector a] -> Value # toEncodingList :: [Vector a] -> Encoding # omitField :: Vector a -> Bool #
(Vector Vector a, ToJSON a) => ToJSON (Vector a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Vector a -> Value # toEncoding :: Vector a -> Encoding # toJSONList :: [Vector a] -> Value # toEncodingList :: [Vector a] -> Encoding # omitField :: Vector a -> Bool #
ToJSON a => ToJSON (Maybe a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Maybe a -> Value # toEncoding :: Maybe a -> Encoding # toJSONList :: [Maybe a] -> Value # toEncodingList :: [Maybe a] -> Encoding # omitField :: Maybe a -> Bool #
ToJSON a => ToJSON (a)	Since: aeson-2.0.2.0
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: (a) -> Value # toEncoding :: (a) -> Encoding # toJSONList :: [(a)] -> Value # toEncodingList :: [(a)] -> Encoding # omitField :: (a) -> Bool #
ToJSON a => ToJSON [a]
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: [a] -> Value # toEncoding :: [a] -> Encoding # toJSONList :: [[a]] -> Value # toEncodingList :: [[a]] -> Encoding # omitField :: [a] -> Bool #
(ToJSON a, ToJSON b) => ToJSON (Either a b)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Either a b -> Value # toEncoding :: Either a b -> Encoding # toJSONList :: [Either a b] -> Value # toEncodingList :: [Either a b] -> Encoding # omitField :: Either a b -> Bool #
HasResolution a => ToJSON (Fixed a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Fixed a -> Value # toEncoding :: Fixed a -> Encoding # toJSONList :: [Fixed a] -> Value # toEncodingList :: [Fixed a] -> Encoding # omitField :: Fixed a -> Bool #
ToJSON (Proxy a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Proxy a -> Value # toEncoding :: Proxy a -> Encoding # toJSONList :: [Proxy a] -> Value # toEncodingList :: [Proxy a] -> Encoding # omitField :: Proxy a -> Bool #
(ToJSON v, ToJSONKey k) => ToJSON (Map k v)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Map k v -> Value # toEncoding :: Map k v -> Encoding # toJSONList :: [Map k v] -> Value # toEncodingList :: [Map k v] -> Encoding # omitField :: Map k v -> Bool #
(ToJSON a, ToJSON b) => ToJSON (Either a b)	Since: aeson-1.5.3.0
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Either a b -> Value # toEncoding :: Either a b -> Encoding # toJSONList :: [Either a b] -> Value # toEncodingList :: [Either a b] -> Encoding # omitField :: Either a b -> Bool #
(ToJSON a, ToJSON b) => ToJSON (These a b)	Since: aeson-1.5.3.0
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: These a b -> Value # toEncoding :: These a b -> Encoding # toJSONList :: [These a b] -> Value # toEncodingList :: [These a b] -> Encoding # omitField :: These a b -> Bool #
(ToJSON a, ToJSON b) => ToJSON (Pair a b)	Since: aeson-1.5.3.0
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Pair a b -> Value # toEncoding :: Pair a b -> Encoding # toJSONList :: [Pair a b] -> Value # toEncodingList :: [Pair a b] -> Encoding # omitField :: Pair a b -> Bool #
(ToJSON a, ToJSON b) => ToJSON (These a b)	Since: aeson-1.5.1.0
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: These a b -> Value # toEncoding :: These a b -> Encoding # toJSONList :: [These a b] -> Value # toEncodingList :: [These a b] -> Encoding # omitField :: These a b -> Bool #
(ToJSON v, ToJSONKey k) => ToJSON (HashMap k v)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: HashMap k v -> Value # toEncoding :: HashMap k v -> Encoding # toJSONList :: [HashMap k v] -> Value # toEncodingList :: [HashMap k v] -> Encoding # omitField :: HashMap k v -> Bool #
(ToJSON a, ToJSON b) => ToJSON (a, b)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: (a, b) -> Value # toEncoding :: (a, b) -> Encoding # toJSONList :: [(a, b)] -> Value # toEncodingList :: [(a, b)] -> Encoding # omitField :: (a, b) -> Bool #
ToJSON a => ToJSON (Const a b)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Const a b -> Value # toEncoding :: Const a b -> Encoding # toJSONList :: [Const a b] -> Value # toEncodingList :: [Const a b] -> Encoding # omitField :: Const a b -> Bool #
ToJSON b => ToJSON (Tagged a b)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Tagged a b -> Value # toEncoding :: Tagged a b -> Encoding # toJSONList :: [Tagged a b] -> Value # toEncodingList :: [Tagged a b] -> Encoding # omitField :: Tagged a b -> Bool #
(ToJSON1 f, ToJSON1 g, ToJSON a) => ToJSON (These1 f g a)	Since: aeson-1.5.1.0
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: These1 f g a -> Value # toEncoding :: These1 f g a -> Encoding # toJSONList :: [These1 f g a] -> Value # toEncodingList :: [These1 f g a] -> Encoding # omitField :: These1 f g a -> Bool #
(ToJSON a, ToJSON b, ToJSON c) => ToJSON (a, b, c)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: (a, b, c) -> Value # toEncoding :: (a, b, c) -> Encoding # toJSONList :: [(a, b, c)] -> Value # toEncodingList :: [(a, b, c)] -> Encoding # omitField :: (a, b, c) -> Bool #
(ToJSON1 f, ToJSON1 g, ToJSON a) => ToJSON (Product f g a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Product f g a -> Value # toEncoding :: Product f g a -> Encoding # toJSONList :: [Product f g a] -> Value # toEncodingList :: [Product f g a] -> Encoding # omitField :: Product f g a -> Bool #
(ToJSON1 f, ToJSON1 g, ToJSON a) => ToJSON (Sum f g a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Sum f g a -> Value # toEncoding :: Sum f g a -> Encoding # toJSONList :: [Sum f g a] -> Value # toEncodingList :: [Sum f g a] -> Encoding # omitField :: Sum f g a -> Bool #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d) => ToJSON (a, b, c, d)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: (a, b, c, d) -> Value # toEncoding :: (a, b, c, d) -> Encoding # toJSONList :: [(a, b, c, d)] -> Value # toEncodingList :: [(a, b, c, d)] -> Encoding # omitField :: (a, b, c, d) -> Bool #
(ToJSON1 f, ToJSON1 g, ToJSON a) => ToJSON (Compose f g a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Compose f g a -> Value # toEncoding :: Compose f g a -> Encoding # toJSONList :: [Compose f g a] -> Value # toEncodingList :: [Compose f g a] -> Encoding # omitField :: Compose f g a -> Bool #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e) => ToJSON (a, b, c, d, e)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: (a, b, c, d, e) -> Value # toEncoding :: (a, b, c, d, e) -> Encoding # toJSONList :: [(a, b, c, d, e)] -> Value # toEncodingList :: [(a, b, c, d, e)] -> Encoding # omitField :: (a, b, c, d, e) -> Bool #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f) => ToJSON (a, b, c, d, e, f)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: (a, b, c, d, e, f) -> Value # toEncoding :: (a, b, c, d, e, f) -> Encoding # toJSONList :: [(a, b, c, d, e, f)] -> Value # toEncodingList :: [(a, b, c, d, e, f)] -> Encoding # omitField :: (a, b, c, d, e, f) -> Bool #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g) => ToJSON (a, b, c, d, e, f, g)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: (a, b, c, d, e, f, g) -> Value # toEncoding :: (a, b, c, d, e, f, g) -> Encoding # toJSONList :: [(a, b, c, d, e, f, g)] -> Value # toEncodingList :: [(a, b, c, d, e, f, g)] -> Encoding # omitField :: (a, b, c, d, e, f, g) -> Bool #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h) => ToJSON (a, b, c, d, e, f, g, h)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: (a, b, c, d, e, f, g, h) -> Value # toEncoding :: (a, b, c, d, e, f, g, h) -> Encoding # toJSONList :: [(a, b, c, d, e, f, g, h)] -> Value # toEncodingList :: [(a, b, c, d, e, f, g, h)] -> Encoding # omitField :: (a, b, c, d, e, f, g, h) -> Bool #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i) => ToJSON (a, b, c, d, e, f, g, h, i)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: (a, b, c, d, e, f, g, h, i) -> Value # toEncoding :: (a, b, c, d, e, f, g, h, i) -> Encoding # toJSONList :: [(a, b, c, d, e, f, g, h, i)] -> Value # toEncodingList :: [(a, b, c, d, e, f, g, h, i)] -> Encoding # omitField :: (a, b, c, d, e, f, g, h, i) -> Bool #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j) => ToJSON (a, b, c, d, e, f, g, h, i, j)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: (a, b, c, d, e, f, g, h, i, j) -> Value # toEncoding :: (a, b, c, d, e, f, g, h, i, j) -> Encoding # toJSONList :: [(a, b, c, d, e, f, g, h, i, j)] -> Value # toEncodingList :: [(a, b, c, d, e, f, g, h, i, j)] -> Encoding # omitField :: (a, b, c, d, e, f, g, h, i, j) -> Bool #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j, ToJSON k) => ToJSON (a, b, c, d, e, f, g, h, i, j, k)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: (a, b, c, d, e, f, g, h, i, j, k) -> Value # toEncoding :: (a, b, c, d, e, f, g, h, i, j, k) -> Encoding # toJSONList :: [(a, b, c, d, e, f, g, h, i, j, k)] -> Value # toEncodingList :: [(a, b, c, d, e, f, g, h, i, j, k)] -> Encoding # omitField :: (a, b, c, d, e, f, g, h, i, j, k) -> Bool #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j, ToJSON k, ToJSON l) => ToJSON (a, b, c, d, e, f, g, h, i, j, k, l)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: (a, b, c, d, e, f, g, h, i, j, k, l) -> Value # toEncoding :: (a, b, c, d, e, f, g, h, i, j, k, l) -> Encoding # toJSONList :: [(a, b, c, d, e, f, g, h, i, j, k, l)] -> Value # toEncodingList :: [(a, b, c, d, e, f, g, h, i, j, k, l)] -> Encoding # omitField :: (a, b, c, d, e, f, g, h, i, j, k, l) -> Bool #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j, ToJSON k, ToJSON l, ToJSON m) => ToJSON (a, b, c, d, e, f, g, h, i, j, k, l, m)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> Value # toEncoding :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> Encoding # toJSONList :: [(a, b, c, d, e, f, g, h, i, j, k, l, m)] -> Value # toEncodingList :: [(a, b, c, d, e, f, g, h, i, j, k, l, m)] -> Encoding # omitField :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> Bool #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j, ToJSON k, ToJSON l, ToJSON m, ToJSON n) => ToJSON (a, b, c, d, e, f, g, h, i, j, k, l, m, n)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> Value # toEncoding :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> Encoding # toJSONList :: [(a, b, c, d, e, f, g, h, i, j, k, l, m, n)] -> Value # toEncodingList :: [(a, b, c, d, e, f, g, h, i, j, k, l, m, n)] -> Encoding # omitField :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> Bool #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j, ToJSON k, ToJSON l, ToJSON m, ToJSON n, ToJSON o) => ToJSON (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> Value # toEncoding :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> Encoding # toJSONList :: [(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)] -> Value # toEncodingList :: [(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)] -> Encoding # omitField :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> Bool #

class FromJSON a where #

A type that can be converted from JSON, with the possibility of failure.

In many cases, you can get the compiler to generate parsing code for you (see below). To begin, let's cover writing an instance by hand.

There are various reasons a conversion could fail. For example, an Object could be missing a required key, an Array could be of the wrong size, or a value could be of an incompatible type.

The basic ways to signal a failed conversion are as follows:

fail yields a custom error message: it is the recommended way of reporting a failure;
empty (or mzero) is uninformative: use it when the error is meant to be caught by some (<|>);
typeMismatch can be used to report a failure when the encountered value is not of the expected JSON type; unexpected is an appropriate alternative when more than one type may be expected, or to keep the expected type implicit.

prependFailure (or modifyFailure) add more information to a parser's error messages.

An example type and instance using typeMismatch and prependFailure:

-- Allow ourselves to write Text literals.
{-# LANGUAGE OverloadedStrings #-}

data Coord = Coord { x :: Double, y :: Double }

instance FromJSON Coord where
    parseJSON (Object v) = Coord
        <$> v .: "x"
        <*> v .: "y"

    -- We do not expect a non-Object value here.
    -- We could use empty to fail, but typeMismatch
    -- gives a much more informative error message.
    parseJSON invalid    =
        prependFailure "parsing Coord failed, "
            (typeMismatch "Object" invalid)

For this common case of only being concerned with a single type of JSON value, the functions withObject, withScientific, etc. are provided. Their use is to be preferred when possible, since they are more terse. Using withObject, we can rewrite the above instance (assuming the same language extension and data type) as:

instance FromJSON Coord where
    parseJSON = withObject "Coord" $ \v -> Coord
        <$> v .: "x"
        <*> v .: "y"

Instead of manually writing your FromJSON instance, there are two options to do it automatically:

Data.Aeson.TH provides Template Haskell functions which will derive an instance at compile time. The generated instance is optimized for your type so it will probably be more efficient than the following option.
The compiler can provide a default generic implementation for parseJSON.

To use the second, simply add a deriving Generic clause to your datatype and declare a FromJSON instance for your datatype without giving a definition for parseJSON.

For example, the previous example can be simplified to just:

{-# LANGUAGE DeriveGeneric #-}

import GHC.Generics

data Coord = Coord { x :: Double, y :: Double } deriving Generic

instance FromJSON Coord

or using the DerivingVia extension

deriving via Generically Coord instance FromJSON Coord

The default implementation will be equivalent to parseJSON = genericParseJSON defaultOptions; if you need different options, you can customize the generic decoding by defining:

customOptions = defaultOptions
                { fieldLabelModifier = map toUpper
                }

instance FromJSON Coord where
    parseJSON = genericParseJSON customOptions

Minimal complete definition

Nothing

Methods

parseJSON :: Value -> Parser a #

parseJSONList :: Value -> Parser [a] #

omittedField :: Maybe a #

Default value for optional fields. Used by (.:?=) operator, and Generics and TH deriving with allowOmittedFields = True (default).

Since: aeson-2.2.0.0

Instances

Instances details

FromJSON Key
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Key # parseJSONList :: Value -> Parser [Key] # omittedField :: Maybe Key #
FromJSON DotNetTime
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser DotNetTime # parseJSONList :: Value -> Parser [DotNetTime] # omittedField :: Maybe DotNetTime #
FromJSON Value
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Value # parseJSONList :: Value -> Parser [Value] # omittedField :: Maybe Value #
FromJSON All	Since: aeson-2.2.3.0
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser All # parseJSONList :: Value -> Parser [All] # omittedField :: Maybe All #
FromJSON Any	Since: aeson-2.2.3.0
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Any # parseJSONList :: Value -> Parser [Any] # omittedField :: Maybe Any #
FromJSON Version
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Version # parseJSONList :: Value -> Parser [Version] # omittedField :: Maybe Version #
FromJSON CTime
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser CTime # parseJSONList :: Value -> Parser [CTime] # omittedField :: Maybe CTime #
FromJSON Void
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Void # parseJSONList :: Value -> Parser [Void] # omittedField :: Maybe Void #
FromJSON Int16
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Int16 # parseJSONList :: Value -> Parser [Int16] # omittedField :: Maybe Int16 #
FromJSON Int32
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Int32 # parseJSONList :: Value -> Parser [Int32] # omittedField :: Maybe Int32 #
FromJSON Int64
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Int64 # parseJSONList :: Value -> Parser [Int64] # omittedField :: Maybe Int64 #
FromJSON Int8
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Int8 # parseJSONList :: Value -> Parser [Int8] # omittedField :: Maybe Int8 #
FromJSON Word16
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Word16 # parseJSONList :: Value -> Parser [Word16] # omittedField :: Maybe Word16 #
FromJSON Word32
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Word32 # parseJSONList :: Value -> Parser [Word32] # omittedField :: Maybe Word32 #
FromJSON Word64
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Word64 # parseJSONList :: Value -> Parser [Word64] # omittedField :: Maybe Word64 #
FromJSON Word8
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Word8 # parseJSONList :: Value -> Parser [Word8] # omittedField :: Maybe Word8 #
FromJSON IntSet
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser IntSet # parseJSONList :: Value -> Parser [IntSet] # omittedField :: Maybe IntSet #
FromJSON Ordering
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Ordering # parseJSONList :: Value -> Parser [Ordering] # omittedField :: Maybe Ordering #
FromJSON URI	Since: aeson-2.2.0.0
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser URI # parseJSONList :: Value -> Parser [URI] # omittedField :: Maybe URI #
FromJSON Scientific
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Scientific # parseJSONList :: Value -> Parser [Scientific] # omittedField :: Maybe Scientific #
FromJSON Text
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Text # parseJSONList :: Value -> Parser [Text] # omittedField :: Maybe Text #
FromJSON Text
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Text # parseJSONList :: Value -> Parser [Text] # omittedField :: Maybe Text #
FromJSON ShortText	Since: aeson-2.0.2.0
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser ShortText # parseJSONList :: Value -> Parser [ShortText] # omittedField :: Maybe ShortText #
FromJSON CalendarDiffDays
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser CalendarDiffDays # parseJSONList :: Value -> Parser [CalendarDiffDays] # omittedField :: Maybe CalendarDiffDays #
FromJSON Day
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Day # parseJSONList :: Value -> Parser [Day] # omittedField :: Maybe Day #
FromJSON Month
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Month # parseJSONList :: Value -> Parser [Month] # omittedField :: Maybe Month #
FromJSON Quarter
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Quarter # parseJSONList :: Value -> Parser [Quarter] # omittedField :: Maybe Quarter #
FromJSON QuarterOfYear
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser QuarterOfYear # parseJSONList :: Value -> Parser [QuarterOfYear] # omittedField :: Maybe QuarterOfYear #
FromJSON DayOfWeek
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser DayOfWeek # parseJSONList :: Value -> Parser [DayOfWeek] # omittedField :: Maybe DayOfWeek #
FromJSON DiffTime	This instance includes a bounds check to prevent maliciously large inputs to fill up the memory of the target system. You can newtype `Scientific` and provide your own instance using `withScientific` if you want to allow larger inputs.
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser DiffTime # parseJSONList :: Value -> Parser [DiffTime] # omittedField :: Maybe DiffTime #
FromJSON NominalDiffTime	This instance includes a bounds check to prevent maliciously large inputs to fill up the memory of the target system. You can newtype `Scientific` and provide your own instance using `withScientific` if you want to allow larger inputs.
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser NominalDiffTime # parseJSONList :: Value -> Parser [NominalDiffTime] # omittedField :: Maybe NominalDiffTime #
FromJSON SystemTime
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser SystemTime # parseJSONList :: Value -> Parser [SystemTime] # omittedField :: Maybe SystemTime #
FromJSON UTCTime
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser UTCTime # parseJSONList :: Value -> Parser [UTCTime] # omittedField :: Maybe UTCTime #
FromJSON CalendarDiffTime
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser CalendarDiffTime # parseJSONList :: Value -> Parser [CalendarDiffTime] # omittedField :: Maybe CalendarDiffTime #
FromJSON LocalTime
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser LocalTime # parseJSONList :: Value -> Parser [LocalTime] # omittedField :: Maybe LocalTime #
FromJSON TimeOfDay
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser TimeOfDay # parseJSONList :: Value -> Parser [TimeOfDay] # omittedField :: Maybe TimeOfDay #
FromJSON ZonedTime	Supported string formats: `YYYY-MM-DD HH:MMZ` `YYYY-MM-DD HH:MM:SSZ` `YYYY-MM-DD HH:MM:SS.SSSZ` The first space may instead be a `T`, and the second space is optional. The `Z` represents UTC. The `Z` may be replaced with a time zone offset of the form `+0000` or `-08:00`, where the first two digits are hours, the `:` is optional and the second two digits (also optional) are minutes.
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser ZonedTime # parseJSONList :: Value -> Parser [ZonedTime] # omittedField :: Maybe ZonedTime #
FromJSON UUID
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser UUID # parseJSONList :: Value -> Parser [UUID] # omittedField :: Maybe UUID #
FromJSON Integer	This instance includes a bounds check to prevent maliciously large inputs to fill up the memory of the target system. You can newtype `Scientific` and provide your own instance using `withScientific` if you want to allow larger inputs.
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Integer # parseJSONList :: Value -> Parser [Integer] # omittedField :: Maybe Integer #
FromJSON Natural
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Natural # parseJSONList :: Value -> Parser [Natural] # omittedField :: Maybe Natural #
FromJSON ()
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser () # parseJSONList :: Value -> Parser [()] # omittedField :: Maybe () #
FromJSON Bool
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Bool # parseJSONList :: Value -> Parser [Bool] # omittedField :: Maybe Bool #
FromJSON Char
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Char # parseJSONList :: Value -> Parser [Char] # omittedField :: Maybe Char #
FromJSON Double
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Double # parseJSONList :: Value -> Parser [Double] # omittedField :: Maybe Double #
FromJSON Float
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Float # parseJSONList :: Value -> Parser [Float] # omittedField :: Maybe Float #
FromJSON Int
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Int # parseJSONList :: Value -> Parser [Int] # omittedField :: Maybe Int #
FromJSON Word
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser Word # parseJSONList :: Value -> Parser [Word] # omittedField :: Maybe Word #
FromJSON v => FromJSON (KeyMap v)	Since: aeson-2.0.1.0
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (KeyMap v) # parseJSONList :: Value -> Parser [KeyMap v] # omittedField :: Maybe (KeyMap v) #
FromJSON a => FromJSON (Identity a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Identity a) # parseJSONList :: Value -> Parser [Identity a] # omittedField :: Maybe (Identity a) #
FromJSON a => FromJSON (First a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (First a) # parseJSONList :: Value -> Parser [First a] # omittedField :: Maybe (First a) #
FromJSON a => FromJSON (Last a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Last a) # parseJSONList :: Value -> Parser [Last a] # omittedField :: Maybe (Last a) #
FromJSON a => FromJSON (Down a)	Since: aeson-2.2.0.0
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Down a) # parseJSONList :: Value -> Parser [Down a] # omittedField :: Maybe (Down a) #
FromJSON a => FromJSON (First a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (First a) # parseJSONList :: Value -> Parser [First a] # omittedField :: Maybe (First a) #
FromJSON a => FromJSON (Last a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Last a) # parseJSONList :: Value -> Parser [Last a] # omittedField :: Maybe (Last a) #
FromJSON a => FromJSON (Max a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Max a) # parseJSONList :: Value -> Parser [Max a] # omittedField :: Maybe (Max a) #
FromJSON a => FromJSON (Min a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Min a) # parseJSONList :: Value -> Parser [Min a] # omittedField :: Maybe (Min a) #
FromJSON a => FromJSON (WrappedMonoid a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (WrappedMonoid a) # parseJSONList :: Value -> Parser [WrappedMonoid a] # omittedField :: Maybe (WrappedMonoid a) #
FromJSON a => FromJSON (Dual a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Dual a) # parseJSONList :: Value -> Parser [Dual a] # omittedField :: Maybe (Dual a) #
FromJSON a => FromJSON (Product a)	Since: aeson-2.2.3.0
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Product a) # parseJSONList :: Value -> Parser [Product a] # omittedField :: Maybe (Product a) #
FromJSON a => FromJSON (Sum a)	Since: aeson-2.2.3.0
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Sum a) # parseJSONList :: Value -> Parser [Sum a] # omittedField :: Maybe (Sum a) #
FromJSON a => FromJSON (NonEmpty a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (NonEmpty a) # parseJSONList :: Value -> Parser [NonEmpty a] # omittedField :: Maybe (NonEmpty a) #
(Generic a, GFromJSON Zero (Rep a)) => FromJSON (Generically a)	Since: aeson-2.1.0.0
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Generically a) # parseJSONList :: Value -> Parser [Generically a] # omittedField :: Maybe (Generically a) #
(FromJSON a, Integral a) => FromJSON (Ratio a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Ratio a) # parseJSONList :: Value -> Parser [Ratio a] # omittedField :: Maybe (Ratio a) #
FromJSON a => FromJSON (IntMap a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (IntMap a) # parseJSONList :: Value -> Parser [IntMap a] # omittedField :: Maybe (IntMap a) #
FromJSON a => FromJSON (Seq a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Seq a) # parseJSONList :: Value -> Parser [Seq a] # omittedField :: Maybe (Seq a) #
(Ord a, FromJSON a) => FromJSON (Set a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Set a) # parseJSONList :: Value -> Parser [Set a] # omittedField :: Maybe (Set a) #
FromJSON v => FromJSON (Tree v)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Tree v) # parseJSONList :: Value -> Parser [Tree v] # omittedField :: Maybe (Tree v) #
FromJSON1 f => FromJSON (Fix f)	Since: aeson-1.5.3.0
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Fix f) # parseJSONList :: Value -> Parser [Fix f] # omittedField :: Maybe (Fix f) #
(FromJSON1 f, Functor f) => FromJSON (Mu f)	Since: aeson-1.5.3.0
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Mu f) # parseJSONList :: Value -> Parser [Mu f] # omittedField :: Maybe (Mu f) #
(FromJSON1 f, Functor f) => FromJSON (Nu f)	Since: aeson-1.5.3.0
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Nu f) # parseJSONList :: Value -> Parser [Nu f] # omittedField :: Maybe (Nu f) #
FromJSON a => FromJSON (DNonEmpty a)	Since: aeson-1.5.3.0
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (DNonEmpty a) # parseJSONList :: Value -> Parser [DNonEmpty a] # omittedField :: Maybe (DNonEmpty a) #
FromJSON a => FromJSON (DList a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (DList a) # parseJSONList :: Value -> Parser [DList a] # omittedField :: Maybe (DList a) #
FromJSON a => FromJSON (Array a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Array a) # parseJSONList :: Value -> Parser [Array a] # omittedField :: Maybe (Array a) #
(Prim a, FromJSON a) => FromJSON (PrimArray a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (PrimArray a) # parseJSONList :: Value -> Parser [PrimArray a] # omittedField :: Maybe (PrimArray a) #
FromJSON a => FromJSON (SmallArray a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (SmallArray a) # parseJSONList :: Value -> Parser [SmallArray a] # omittedField :: Maybe (SmallArray a) #
FromJSON a => FromJSON (Maybe a)	Since: aeson-1.5.3.0
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Maybe a) # parseJSONList :: Value -> Parser [Maybe a] # omittedField :: Maybe0 (Maybe a) #
(Eq a, Hashable a, FromJSON a) => FromJSON (HashSet a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (HashSet a) # parseJSONList :: Value -> Parser [HashSet a] # omittedField :: Maybe (HashSet a) #
FromJSON a => FromJSON (Vector a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Vector a) # parseJSONList :: Value -> Parser [Vector a] # omittedField :: Maybe (Vector a) #
(Prim a, FromJSON a) => FromJSON (Vector a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Vector a) # parseJSONList :: Value -> Parser [Vector a] # omittedField :: Maybe (Vector a) #
(Storable a, FromJSON a) => FromJSON (Vector a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Vector a) # parseJSONList :: Value -> Parser [Vector a] # omittedField :: Maybe (Vector a) #
(Vector Vector a, FromJSON a) => FromJSON (Vector a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Vector a) # parseJSONList :: Value -> Parser [Vector a] # omittedField :: Maybe (Vector a) #
FromJSON a => FromJSON (Maybe a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Maybe a) # parseJSONList :: Value -> Parser [Maybe a] # omittedField :: Maybe (Maybe a) #
FromJSON a => FromJSON (a)	Since: aeson-2.0.2.0
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (a) # parseJSONList :: Value -> Parser [(a)] # omittedField :: Maybe (a) #
FromJSON a => FromJSON [a]
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser [a] # parseJSONList :: Value -> Parser [[a]] # omittedField :: Maybe [a] #
(FromJSON a, FromJSON b) => FromJSON (Either a b)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Either a b) # parseJSONList :: Value -> Parser [Either a b] # omittedField :: Maybe (Either a b) #
HasResolution a => FromJSON (Fixed a)	This instance includes a bounds check to prevent maliciously large inputs to fill up the memory of the target system. You can newtype `Scientific` and provide your own instance using `withScientific` if you want to allow larger inputs.
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Fixed a) # parseJSONList :: Value -> Parser [Fixed a] # omittedField :: Maybe (Fixed a) #
FromJSON (Proxy a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Proxy a) # parseJSONList :: Value -> Parser [Proxy a] # omittedField :: Maybe (Proxy a) #
(FromJSONKey k, Ord k, FromJSON v) => FromJSON (Map k v)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Map k v) # parseJSONList :: Value -> Parser [Map k v] # omittedField :: Maybe (Map k v) #
(FromJSON a, FromJSON b) => FromJSON (Either a b)	Since: aeson-1.5.3.0
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Either a b) # parseJSONList :: Value -> Parser [Either a b] # omittedField :: Maybe (Either a b) #
(FromJSON a, FromJSON b) => FromJSON (These a b)	Since: aeson-1.5.3.0
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (These a b) # parseJSONList :: Value -> Parser [These a b] # omittedField :: Maybe (These a b) #
(FromJSON a, FromJSON b) => FromJSON (Pair a b)	Since: aeson-1.5.3.0
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Pair a b) # parseJSONList :: Value -> Parser [Pair a b] # omittedField :: Maybe (Pair a b) #
(FromJSON a, FromJSON b) => FromJSON (These a b)	Since: aeson-1.5.1.0
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (These a b) # parseJSONList :: Value -> Parser [These a b] # omittedField :: Maybe (These a b) #
(FromJSON v, FromJSONKey k, Eq k, Hashable k) => FromJSON (HashMap k v)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (HashMap k v) # parseJSONList :: Value -> Parser [HashMap k v] # omittedField :: Maybe (HashMap k v) #
(FromJSON a, FromJSON b) => FromJSON (a, b)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (a, b) # parseJSONList :: Value -> Parser [(a, b)] # omittedField :: Maybe (a, b) #
FromJSON a => FromJSON (Const a b)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Const a b) # parseJSONList :: Value -> Parser [Const a b] # omittedField :: Maybe (Const a b) #
FromJSON b => FromJSON (Tagged a b)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Tagged a b) # parseJSONList :: Value -> Parser [Tagged a b] # omittedField :: Maybe (Tagged a b) #
(FromJSON1 f, FromJSON1 g, FromJSON a) => FromJSON (These1 f g a)	Since: aeson-1.5.1.0
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (These1 f g a) # parseJSONList :: Value -> Parser [These1 f g a] # omittedField :: Maybe (These1 f g a) #
(FromJSON a, FromJSON b, FromJSON c) => FromJSON (a, b, c)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (a, b, c) # parseJSONList :: Value -> Parser [(a, b, c)] # omittedField :: Maybe (a, b, c) #
(FromJSON1 f, FromJSON1 g, FromJSON a) => FromJSON (Product f g a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Product f g a) # parseJSONList :: Value -> Parser [Product f g a] # omittedField :: Maybe (Product f g a) #
(FromJSON1 f, FromJSON1 g, FromJSON a) => FromJSON (Sum f g a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Sum f g a) # parseJSONList :: Value -> Parser [Sum f g a] # omittedField :: Maybe (Sum f g a) #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d) => FromJSON (a, b, c, d)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (a, b, c, d) # parseJSONList :: Value -> Parser [(a, b, c, d)] # omittedField :: Maybe (a, b, c, d) #
(FromJSON1 f, FromJSON1 g, FromJSON a) => FromJSON (Compose f g a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Compose f g a) # parseJSONList :: Value -> Parser [Compose f g a] # omittedField :: Maybe (Compose f g a) #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e) => FromJSON (a, b, c, d, e)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (a, b, c, d, e) # parseJSONList :: Value -> Parser [(a, b, c, d, e)] # omittedField :: Maybe (a, b, c, d, e) #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f) => FromJSON (a, b, c, d, e, f)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (a, b, c, d, e, f) # parseJSONList :: Value -> Parser [(a, b, c, d, e, f)] # omittedField :: Maybe (a, b, c, d, e, f) #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g) => FromJSON (a, b, c, d, e, f, g)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (a, b, c, d, e, f, g) # parseJSONList :: Value -> Parser [(a, b, c, d, e, f, g)] # omittedField :: Maybe (a, b, c, d, e, f, g) #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h) => FromJSON (a, b, c, d, e, f, g, h)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (a, b, c, d, e, f, g, h) # parseJSONList :: Value -> Parser [(a, b, c, d, e, f, g, h)] # omittedField :: Maybe (a, b, c, d, e, f, g, h) #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i) => FromJSON (a, b, c, d, e, f, g, h, i)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (a, b, c, d, e, f, g, h, i) # parseJSONList :: Value -> Parser [(a, b, c, d, e, f, g, h, i)] # omittedField :: Maybe (a, b, c, d, e, f, g, h, i) #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j) => FromJSON (a, b, c, d, e, f, g, h, i, j)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (a, b, c, d, e, f, g, h, i, j) # parseJSONList :: Value -> Parser [(a, b, c, d, e, f, g, h, i, j)] # omittedField :: Maybe (a, b, c, d, e, f, g, h, i, j) #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j, FromJSON k) => FromJSON (a, b, c, d, e, f, g, h, i, j, k)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (a, b, c, d, e, f, g, h, i, j, k) # parseJSONList :: Value -> Parser [(a, b, c, d, e, f, g, h, i, j, k)] # omittedField :: Maybe (a, b, c, d, e, f, g, h, i, j, k) #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j, FromJSON k, FromJSON l) => FromJSON (a, b, c, d, e, f, g, h, i, j, k, l)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (a, b, c, d, e, f, g, h, i, j, k, l) # parseJSONList :: Value -> Parser [(a, b, c, d, e, f, g, h, i, j, k, l)] # omittedField :: Maybe (a, b, c, d, e, f, g, h, i, j, k, l) #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j, FromJSON k, FromJSON l, FromJSON m) => FromJSON (a, b, c, d, e, f, g, h, i, j, k, l, m)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (a, b, c, d, e, f, g, h, i, j, k, l, m) # parseJSONList :: Value -> Parser [(a, b, c, d, e, f, g, h, i, j, k, l, m)] # omittedField :: Maybe (a, b, c, d, e, f, g, h, i, j, k, l, m) #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j, FromJSON k, FromJSON l, FromJSON m, FromJSON n) => FromJSON (a, b, c, d, e, f, g, h, i, j, k, l, m, n)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (a, b, c, d, e, f, g, h, i, j, k, l, m, n) # parseJSONList :: Value -> Parser [(a, b, c, d, e, f, g, h, i, j, k, l, m, n)] # omittedField :: Maybe (a, b, c, d, e, f, g, h, i, j, k, l, m, n) #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j, FromJSON k, FromJSON l, FromJSON m, FromJSON n, FromJSON o) => FromJSON (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) # parseJSONList :: Value -> Parser [(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)] # omittedField :: Maybe (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) #

data Proxy (t :: k) #

Proxy is a type that holds no data, but has a phantom parameter of arbitrary type (or even kind). Its use is to provide type information, even though there is no value available of that type (or it may be too costly to create one).

Historically, Proxy :: Proxy a is a safer alternative to the undefined :: a idiom.

>>> Proxy :: Proxy (Void, Int -> Int)
Proxy

Proxy can even hold types of higher kinds,

>>> Proxy :: Proxy Either
Proxy

>>> Proxy :: Proxy Functor
Proxy

>>> Proxy :: Proxy complicatedStructure
Proxy

Constructors

Proxy

Instances

Instances details

Generic1 (Proxy :: k -> Type)
Instance details Defined in GHC.Generics Associated Types type Rep1 Proxy :: k -> Type # Methods from1 :: forall (a :: k0). Proxy a -> Rep1 Proxy a # to1 :: forall (a :: k0). Rep1 Proxy a -> Proxy a #
FromJSON1 (Proxy :: Type -> Type)
Instance details Defined in Data.Aeson.Types.FromJSON Methods liftParseJSON :: Maybe a -> (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (Proxy a) # liftParseJSONList :: Maybe a -> (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [Proxy a] # liftOmittedField :: Maybe a -> Maybe (Proxy a) #
ToJSON1 (Proxy :: Type -> Type)
Instance details Defined in Data.Aeson.Types.ToJSON Methods liftToJSON :: (a -> Bool) -> (a -> Value) -> ([a] -> Value) -> Proxy a -> Value # liftToJSONList :: (a -> Bool) -> (a -> Value) -> ([a] -> Value) -> [Proxy a] -> Value # liftToEncoding :: (a -> Bool) -> (a -> Encoding) -> ([a] -> Encoding) -> Proxy a -> Encoding # liftToEncodingList :: (a -> Bool) -> (a -> Encoding) -> ([a] -> Encoding) -> [Proxy a] -> Encoding # liftOmitField :: (a -> Bool) -> Proxy a -> Bool #
Foldable (Proxy :: Type -> Type)	Since: base-4.7.0.0
Instance details Defined in Data.Foldable Methods fold :: Monoid m => Proxy m -> m # foldMap :: Monoid m => (a -> m) -> Proxy a -> m # foldMap' :: Monoid m => (a -> m) -> Proxy a -> m # foldr :: (a -> b -> b) -> b -> Proxy a -> b # foldr' :: (a -> b -> b) -> b -> Proxy a -> b # foldl :: (b -> a -> b) -> b -> Proxy a -> b # foldl' :: (b -> a -> b) -> b -> Proxy a -> b # foldr1 :: (a -> a -> a) -> Proxy a -> a # foldl1 :: (a -> a -> a) -> Proxy a -> a # toList :: Proxy a -> [a] # null :: Proxy a -> Bool # length :: Proxy a -> Int # elem :: Eq a => a -> Proxy a -> Bool # maximum :: Ord a => Proxy a -> a # minimum :: Ord a => Proxy a -> a # sum :: Num a => Proxy a -> a # product :: Num a => Proxy a -> a #
Traversable (Proxy :: Type -> Type)	Since: base-4.7.0.0
Instance details Defined in Data.Traversable Methods traverse :: Applicative f => (a -> f b) -> Proxy a -> f (Proxy b) # sequenceA :: Applicative f => Proxy (f a) -> f (Proxy a) # mapM :: Monad m => (a -> m b) -> Proxy a -> m (Proxy b) # sequence :: Monad m => Proxy (m a) -> m (Proxy a) #
Alternative (Proxy :: Type -> Type)	Since: base-4.9.0.0
Instance details Defined in Data.Proxy Methods empty :: Proxy a # (<\|>) :: Proxy a -> Proxy a -> Proxy a # some :: Proxy a -> Proxy [a] # many :: Proxy a -> Proxy [a] #
Applicative (Proxy :: Type -> Type)	Since: base-4.7.0.0
Instance details Defined in Data.Proxy Methods pure :: a -> Proxy a # (<>) :: Proxy (a -> b) -> Proxy a -> Proxy b # liftA2 :: (a -> b -> c) -> Proxy a -> Proxy b -> Proxy c # (>) :: Proxy a -> Proxy b -> Proxy b # (<*) :: Proxy a -> Proxy b -> Proxy a #
Functor (Proxy :: Type -> Type)	Since: base-4.7.0.0
Instance details Defined in Data.Proxy Methods fmap :: (a -> b) -> Proxy a -> Proxy b # (<$) :: a -> Proxy b -> Proxy a #
Monad (Proxy :: Type -> Type)	Since: base-4.7.0.0
Instance details Defined in Data.Proxy Methods (>>=) :: Proxy a -> (a -> Proxy b) -> Proxy b # (>>) :: Proxy a -> Proxy b -> Proxy b # return :: a -> Proxy a #
MonadPlus (Proxy :: Type -> Type)	Since: base-4.9.0.0
Instance details Defined in Data.Proxy Methods mzero :: Proxy a # mplus :: Proxy a -> Proxy a -> Proxy a #
Hashable1 (Proxy :: Type -> Type)
Instance details Defined in Data.Hashable.Class Methods liftHashWithSalt :: (Int -> a -> Int) -> Int -> Proxy a -> Int #
FromJSON (Proxy a)
Instance details Defined in Data.Aeson.Types.FromJSON Methods parseJSON :: Value -> Parser (Proxy a) # parseJSONList :: Value -> Parser [Proxy a] # omittedField :: Maybe (Proxy a) #
ToJSON (Proxy a)
Instance details Defined in Data.Aeson.Types.ToJSON Methods toJSON :: Proxy a -> Value # toEncoding :: Proxy a -> Encoding # toJSONList :: [Proxy a] -> Value # toEncodingList :: [Proxy a] -> Encoding # omitField :: Proxy a -> Bool #
Monoid (Proxy s)	Since: base-4.7.0.0
Instance details Defined in Data.Proxy Methods mempty :: Proxy s # mappend :: Proxy s -> Proxy s -> Proxy s # mconcat :: [Proxy s] -> Proxy s #
Semigroup (Proxy s)	Since: base-4.9.0.0
Instance details Defined in Data.Proxy Methods (<>) :: Proxy s -> Proxy s -> Proxy s # sconcat :: NonEmpty (Proxy s) -> Proxy s # stimes :: Integral b => b -> Proxy s -> Proxy s #
Bounded (Proxy t)	Since: base-4.7.0.0
Instance details Defined in Data.Proxy Methods minBound :: Proxy t # maxBound :: Proxy t #
Enum (Proxy s)	Since: base-4.7.0.0
Instance details Defined in Data.Proxy Methods succ :: Proxy s -> Proxy s # pred :: Proxy s -> Proxy s # toEnum :: Int -> Proxy s # fromEnum :: Proxy s -> Int # enumFrom :: Proxy s -> [Proxy s] # enumFromThen :: Proxy s -> Proxy s -> [Proxy s] # enumFromTo :: Proxy s -> Proxy s -> [Proxy s] # enumFromThenTo :: Proxy s -> Proxy s -> Proxy s -> [Proxy s] #
Generic (Proxy t)
Instance details Defined in GHC.Generics Associated Types type Rep (Proxy t) :: Type -> Type # Methods from :: Proxy t -> Rep (Proxy t) x # to :: Rep (Proxy t) x -> Proxy t #
Ix (Proxy s)	Since: base-4.7.0.0
Instance details Defined in Data.Proxy Methods range :: (Proxy s, Proxy s) -> [Proxy s] # index :: (Proxy s, Proxy s) -> Proxy s -> Int # unsafeIndex :: (Proxy s, Proxy s) -> Proxy s -> Int # inRange :: (Proxy s, Proxy s) -> Proxy s -> Bool # rangeSize :: (Proxy s, Proxy s) -> Int # unsafeRangeSize :: (Proxy s, Proxy s) -> Int #
Read (Proxy t)	Since: base-4.7.0.0
Instance details Defined in Data.Proxy Methods readsPrec :: Int -> ReadS (Proxy t) # readList :: ReadS [Proxy t] # readPrec :: ReadPrec (Proxy t) # readListPrec :: ReadPrec [Proxy t] #
Show (Proxy s)	Since: base-4.7.0.0
Instance details Defined in Data.Proxy Methods showsPrec :: Int -> Proxy s -> ShowS # show :: Proxy s -> String # showList :: [Proxy s] -> ShowS #
Eq (Proxy s)	Since: base-4.7.0.0
Instance details Defined in Data.Proxy Methods (==) :: Proxy s -> Proxy s -> Bool # (/=) :: Proxy s -> Proxy s -> Bool #
Ord (Proxy s)	Since: base-4.7.0.0
Instance details Defined in Data.Proxy Methods compare :: Proxy s -> Proxy s -> Ordering # (<) :: Proxy s -> Proxy s -> Bool # (<=) :: Proxy s -> Proxy s -> Bool # (>) :: Proxy s -> Proxy s -> Bool # (>=) :: Proxy s -> Proxy s -> Bool # max :: Proxy s -> Proxy s -> Proxy s # min :: Proxy s -> Proxy s -> Proxy s #
Hashable (Proxy a)
Instance details Defined in Data.Hashable.Class Methods hashWithSalt :: Int -> Proxy a -> Int # hash :: Proxy a -> Int #
type Rep1 (Proxy :: k -> Type)	Since: base-4.6.0.0
Instance details Defined in GHC.Generics type Rep1 (Proxy :: k -> Type) = D1 ('MetaData "Proxy" "Data.Proxy" "base" 'False) (C1 ('MetaCons "Proxy" 'PrefixI 'False) (U1 :: k -> Type))
type Rep (Proxy t)	Since: base-4.6.0.0
Instance details Defined in GHC.Generics type Rep (Proxy t) = D1 ('MetaData "Proxy" "Data.Proxy" "base" 'False) (C1 ('MetaCons "Proxy" 'PrefixI 'False) (U1 :: Type -> Type))
type Code (Proxy t)
Instance details Defined in Generics.SOP.Instances type Code (Proxy t) = '['[] :: [Type]]
type DatatypeInfoOf (Proxy t)
Instance details Defined in Generics.SOP.Instances type DatatypeInfoOf (Proxy t) = 'ADT "Data.Proxy" "Proxy" '['Constructor "Proxy"] '['[] :: [StrictnessInfo]]