Data.Aeson

aeson-1.1.2.0: Fast JSON parsing and encoding

Copyright | (c) 2011-2016 Bryan O'Sullivan (c) 2011 MailRank, Inc.
License | BSD3
Maintainer | Bryan O'Sullivan <bos@serpentine.com>
Stability | experimental
Portability | portable
Safe Haskell | None
Language | Haskell2010

Data.Aeson

Contents

- How to use this library
  - Writing instances by hand
  - Working with the AST
  - Decoding to a Haskell value
  - Decoding a mixed-type object
- Encoding and decoding
  - Direct encoding
  - Variants for strict bytestrings
- Core JSON types
- Convenience types
- Type conversion
  - Keys for maps
  - Liftings to unary and binary type constructors
  - Generic JSON classes and options
- Inspecting ``Value`s`
- Constructors and accessors
- Parsing

Description

Types and functions for working efficiently with JSON data.

(A note on naming: in Greek mythology, Aeson was the father of Jason.)

Synopsis

- decode :: FromJSON a => ByteString -> Maybe a
- decode' :: FromJSON a => ByteString -> Maybe a
- eitherDecode :: FromJSON a => ByteString -> Either String a
- eitherDecode' :: FromJSON a => ByteString -> Either String a
- encode :: ToJSON a => a -> ByteString
- decodeStrict :: FromJSON a => ByteString -> Maybe a
- decodeStrict' :: FromJSON a => ByteString -> Maybe a
- eitherDecodeStrict :: FromJSON a => ByteString -> Either String a
- eitherDecodeStrict' :: FromJSON a => ByteString -> Either String a
- data Value
  - = Object !Object
  - | Array !Array
  - | String !Text
  - | Number !Scientific
  - | Bool !Bool
  - | Null
- type Encoding = Encoding' Value
- fromEncoding :: Encoding' tag -> Builder
- type Array = Vector Value
- type Object = HashMap Text Value
- newtype DotNetTime = DotNetTime {
  - fromDotNetTime :: UTCTime
  }
- class FromJSON a where
- data Result a
  - = Error String
  - | Success a
- fromJSON :: FromJSON a => Value -> Result a
- class ToJSON a where
- class KeyValue kv where
- class ToJSONKey a where
- data ToJSONKeyFunction a
  - = ToJSONKeyText !(a -> Text) !(a -> Encoding' Text)
  - | ToJSONKeyValue !(a -> Value) !(a -> Encoding)
- class FromJSONKey a where
- data FromJSONKeyFunction a
  - = FromJSONKeyCoerce !(CoerceText a)
  - | FromJSONKeyText !(Text -> a)
  - | FromJSONKeyTextParser !(Text -> Parser a)
  - | FromJSONKeyValue !(Value -> Parser a)
- class FromJSON1 f where
- parseJSON1 :: (FromJSON1 f, FromJSON a) => Value -> Parser (f a)
- class FromJSON2 f where
- parseJSON2 :: (FromJSON2 f, FromJSON a, FromJSON b) => Value -> Parser (f a b)
- class ToJSON1 f where
- toJSON1 :: (ToJSON1 f, ToJSON a) => f a -> Value
- toEncoding1 :: (ToJSON1 f, ToJSON a) => f a -> Encoding
- class ToJSON2 f where
- toJSON2 :: (ToJSON2 f, ToJSON a, ToJSON b) => f a b -> Value
- toEncoding2 :: (ToJSON2 f, ToJSON a, ToJSON b) => f a b -> Encoding
- class GFromJSON arity f where
- data FromArgs arity a where
  - NoFromArgs :: FromArgs Zero a
  - From1Args :: (Value -> Parser a) -> (Value -> Parser [a]) -> FromArgs One a
- class GToJSON arity f where
- class GToEncoding arity f where
- data ToArgs res arity a where
  - NoToArgs :: ToArgs res Zero a
  - To1Args :: (a -> res) -> ([a] -> res) -> ToArgs res One a
- data Zero
- data One
- genericToJSON :: (Generic a, GToJSON Zero (Rep a)) => Options -> a -> Value
- genericLiftToJSON :: (Generic1 f, GToJSON One (Rep1 f)) => Options -> (a -> Value) -> ([a] -> Value) -> f a -> Value
- genericToEncoding :: (Generic a, GToEncoding Zero (Rep a)) => Options -> a -> Encoding
- genericLiftToEncoding :: (Generic1 f, GToEncoding One (Rep1 f)) => Options -> (a -> Encoding) -> ([a] -> Encoding) -> f a -> Encoding
- genericParseJSON :: (Generic a, GFromJSON Zero (Rep a)) => Options -> Value -> Parser a
- genericLiftParseJSON :: (Generic1 f, GFromJSON One (Rep1 f)) => Options -> (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (f a)
- defaultOptions :: Options
- withObject :: String -> (Object -> Parser a) -> Value -> Parser a
- withText :: String -> (Text -> Parser a) -> Value -> Parser a
- withArray :: String -> (Array -> Parser a) -> Value -> Parser a
- withNumber :: String -> (Number -> Parser a) -> Value -> Parser a
- withScientific :: String -> (Scientific -> Parser a) -> Value -> Parser a
- withBool :: String -> (Bool -> Parser a) -> Value -> Parser a
- data Series
- pairs :: Series -> Encoding
- foldable :: (Foldable t, ToJSON a) => t a -> Encoding
- (.:) :: FromJSON a => Object -> Text -> Parser a
- (.:?) :: FromJSON a => Object -> Text -> Parser (Maybe a)
- (.:!) :: FromJSON a => Object -> Text -> Parser (Maybe a)
- (.!=) :: Parser (Maybe a) -> a -> Parser a
- object :: [Pair] -> Value
- json :: Parser Value
- json' :: Parser Value

# How to use this library

This section contains basic information on the different ways to work with data using this library. These range from simple but inflexible, to complex but flexible.

The most common way to use the library is to define a data type, corresponding to some JSON data you want to work with, and then write either a `FromJSON` instance, a to `ToJSON` instance, or both for that type.

For example, given this JSON data:

    { "name": "Joe", "age": 12 }

we create a matching data type:

    {-# LANGUAGE DeriveGeneric #-}

    import GHC.Generics

    data Person = Person {
          name :: Text
        , age  :: Int
        } deriving (Generic, Show)

The `LANGUAGE` pragma and `Generic` instance let us write empty `FromJSON` and `ToJSON` instances for which the compiler will generate sensible default implementations.

    instance ToJSON Person where
        -- No need to provide a toJSON implementation.

        -- For efficiency, we write a simple toEncoding implementation, as
        -- the default version uses toJSON.
        toEncoding = genericToEncoding defaultOptions

    instance FromJSON Person
        -- No need to provide a parseJSON implementation.

We can now encode a value like so:

    >>> encode (Person {name = "Joe", age = 12})
    "{\"name\":\"Joe\",\"age\":12}"

## Writing instances by hand

When necessary, we can write `ToJSON` and `FromJSON` instances by hand. This is valuable when the JSON-on-the-wire and Haskell data are different or otherwise need some more carefully managed translation. Let's revisit our JSON data:

    { "name": "Joe", "age": 12 }

We once again create a matching data type, without bothering to add a `Generic` instance this time:

    data Person = Person {
          name :: Text
        , age  :: Int
        } deriving Show

To decode data, we need to define a `FromJSON` instance:

    {-# LANGUAGE OverloadedStrings #-}

    instance FromJSON Person where
        parseJSON = withObject "Person" $ \v -> Person
            <$> v .: "name"
            <*> v .: "age"

We can now parse the JSON data like so:

    >>> decode "{\"name\":\"Joe\",\"age\":12}" :: Maybe Person
    Just (Person {name = "Joe", age = 12})

To encode data, we need to define a `ToJSON` instance. Let's begin with an instance written entirely by hand.

    instance ToJSON Person where
        -- this generates a Value
        toJSON (Person name age) =
            object ["name" .= name, "age" .= age]

        -- this encodes directly to a bytestring Builder
        toEncoding (Person name age) =
            pairs ("name" .= name <> "age" .= age)

We can now encode a value like so:

    >>> encode (Person {name = "Joe", age = 12})
    "{\"name\":\"Joe\",\"age\":12}"

There are predefined `FromJSON` and `ToJSON` instances for many types. Here's an example using lists and `Int`s:

    >>> decode "[1,2,3]" :: Maybe [Int]
    Just [1,2,3]

And here's an example using the `Map` type to get a map of `Int`s.

    >>> decode "{\"foo\":1,\"bar\":2}" :: Maybe (Map String Int)
    Just (fromList [("bar",2),("foo",1)])

## Working with the AST

Sometimes you want to work with JSON data directly, without first converting it to a custom data type. This can be useful if you want to e.g. convert JSON data to YAML data, without knowing what the contents of the original JSON data was. The `Value` type, which is an instance of `FromJSON`, is used to represent an arbitrary JSON AST (abstract syntax tree). Example usage:

    >>> decode "{\"foo\": 123}" :: Maybe Value
    Just (Object (fromList [("foo",Number 123)]))

    >>> decode "{\"foo\": [\"abc\",\"def\"]}" :: Maybe Value
    Just (Object (fromList [("foo",Array (fromList [String "abc",String "def"]))]))

Once you have a `Value` you can write functions to traverse it and make arbitrary transformations.

## Decoding to a Haskell value

We can decode to any instance of `FromJSON`:

    λ> decode "[1,2,3]" :: Maybe [Int]
    Just [1,2,3]

Alternatively, there are instances for standard data types, so you can use them directly. For example, use the `Map` type to get a map of `Int`s.

    λ> import Data.Map
    λ> decode "{\"foo\":1,\"bar\":2}" :: Maybe (Map String Int)
    Just (fromList [("bar",2),("foo",1)])

## Decoding a mixed-type object

The above approach with maps of course will not work for mixed-type objects that don't follow a strict schema, but there are a couple of approaches available for these.

The `Object` type contains JSON objects:

    λ> decode "{\"name\":\"Dave\",\"age\":2}" :: Maybe Object
    Just (fromList) [("name",String "Dave"),("age",Number 2)]

You can extract values from it with a parser using `parse`, `parseEither` or, in this example, `parseMaybe`:

    λ> do result <- decode "{\"name\":\"Dave\",\"age\":2}"
          flip parseMaybe result $ \obj -> do
            age <- obj .: "age"
            name <- obj .: "name"
            return (name ++ ": " ++ show (age*2))

    Just "Dave: 4"

Considering that any type that implements `FromJSON` can be used here, this is quite a powerful way to parse JSON. See the documentation in `FromJSON` for how to implement this class for your own data types.

The downside is that you have to write the parser yourself; the upside is that you have complete control over the way the JSON is parsed.

# Encoding and decoding

Decoding is a two-step process.

- When decoding a value, the process is reversed: the bytes are converted to a `Value`, then the `FromJSON` class is used to convert to the desired type.

There are two ways to encode a value.

- Convert to a `Value` using `toJSON`, then possibly further encode. This was the only method available in aeson 0.9 and earlier.
- Directly encode (to what will become a `ByteString`) using `toEncoding`. This is much more efficient (about 3x faster, and less memory intensive besides), but is only available in aeson 0.10 and newer.

For convenience, the `encode` and `decode` functions combine both steps.

## Direct encoding

In older versions of this library, encoding a Haskell value involved converting to an intermediate `Value`, then encoding that.

A "direct" encoder converts straight from a source Haskell value to a `ByteString` without constructing an intermediate `Value`. This approach is faster than `toJSON`, and allocates less memory. The `toEncoding` method makes it possible to implement direct encoding with low memory overhead.

To complicate matters, the default implementation of `toEncoding` uses `toJSON`. Why? The `toEncoding` method was added to this library much more recently than `toJSON`. Using `toJSON` ensures that packages written against older versions of this library will compile and produce correct output, but they will not see any speedup from direct encoding.

To write a minimal implementation of direct encoding, your type must implement GHC's `Generic` class, and your code should look like this:

        toEncoding = genericToEncoding defaultOptions

What if you have more elaborate encoding needs? For example, perhaps you need to change the names of object keys, omit parts of a value.

To encode to a JSON "object", use the `pairs` function.

        toEncoding (Person name age) =
            pairs ("name" .= name <> "age" .= age)

Any container type that implements `Foldable` can be encoded to a JSON "array" using `foldable`.

    > import Data.Sequence as Seq
    > encode (Seq.fromList [1,2,3])
    "[1,2,3]"

decode :: FromJSON a => ByteString -> Maybe a #

Efficiently deserialize a JSON value from a lazy `ByteString`. If this fails due to incomplete or invalid input, `Nothing` is returned.

The input must consist solely of a JSON document, with no trailing data except for whitespace.

This function parses immediately, but defers conversion. See `json` for details.

decode' :: FromJSON a => ByteString -> Maybe a #

Efficiently deserialize a JSON value from a lazy `ByteString`. If this fails due to incomplete or invalid input, `Nothing` is returned.

The input must consist solely of a JSON document, with no trailing data except for whitespace.

This function parses and performs conversion immediately. See `json'` for details.

eitherDecode :: FromJSON a => ByteString -> Either String a #

Like `decode` but returns an error message when decoding fails.

eitherDecode' :: FromJSON a => ByteString -> Either String a #

Like `decode'` but returns an error message when decoding fails.

encode :: ToJSON a => a -> ByteString #

Efficiently serialize a JSON value as a lazy `ByteString`.

This is implemented in terms of the `ToJSON` class's `toEncoding` method.

## Variants for strict bytestrings

decodeStrict :: FromJSON a => ByteString -> Maybe a #

Efficiently deserialize a JSON value from a strict `ByteString`. If this fails due to incomplete or invalid input, `Nothing` is returned.

The input must consist solely of a JSON document, with no trailing data except for whitespace.

This function parses immediately, but defers conversion. See `json` for details.

decodeStrict' :: FromJSON a => ByteString -> Maybe a #

Efficiently deserialize a JSON value from a strict `ByteString`. If this fails due to incomplete or invalid input, `Nothing` is returned.

The input must consist solely of a JSON document, with no trailing data except for whitespace.

This function parses and performs conversion immediately. See `json'` for details.

eitherDecodeStrict :: FromJSON a => ByteString -> Either String a #

Like `decodeStrict` but returns an error message when decoding fails.

eitherDecodeStrict' :: FromJSON a => ByteString -> Either String a #

Like `decodeStrict'` but returns an error message when decoding fails.

# Core JSON types

data Value #

A JSON value represented as a Haskell value.

Constructors

Object !Object |
Array !Array |
String !Text |
Number !Scientific |
Bool !Bool |
Null |

Instances

Eq Value # |
Methods (==) :: Value -> Value -> Bool # (/=) :: Value -> Value -> Bool #
Data Value # |
Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Value -> c Value # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Value # toConstr :: Value -> Constr # dataTypeOf :: Value -> DataType # dataCast1 :: Typeable (* -> *) t => (forall d. Data d => c (t d)) -> Maybe (c Value) # dataCast2 :: Typeable (* -> * -> *) t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Value) # gmapT :: (forall b. Data b => b -> b) -> Value -> Value # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Value -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Value -> r # gmapQ :: (forall d. Data d => d -> u) -> Value -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Value -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Value -> m Value # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Value -> m Value # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Value -> m Value #
Read Value # |
Methods readsPrec :: Int -> ReadS Value # readList :: ReadS [Value] # readPrec :: ReadPrec Value # readListPrec :: ReadPrec [Value] #
Show Value # |
Methods showsPrec :: Int -> Value -> ShowS # show :: Value -> String # showList :: [Value] -> ShowS #
IsString Value # |
Methods fromString :: String -> Value #
Lift Value # |
Methods lift :: Value -> Q Exp #
NFData Value # |
Methods rnf :: Value -> () #
Hashable Value # |
Methods hashWithSalt :: Int -> Value -> Int # hash :: Value -> Int #
KeyValue Pair # |
Methods (.=) :: ToJSON v => Text -> v -> Pair #
ToJSON Value # |
Methods toJSON :: Value -> Value # toEncoding :: Value -> Encoding # toJSONList :: [Value] -> Value # toEncodingList :: [Value] -> Encoding #
FromJSON Value # |
Methods parseJSON :: Value -> Parser Value # parseJSONList :: Value -> Parser [Value] #

type Encoding = Encoding' Value #

Often used synonnym for `Encoding'`.

fromEncoding :: Encoding' tag -> Builder #

Acquire the underlying bytestring builder.

type Array = Vector Value #

A JSON "array" (sequence).

type Object = HashMap Text Value #

A JSON "object" (key/value map).

# Convenience types

newtype DotNetTime #

A newtype wrapper for `UTCTime` that uses the same non-standard serialization format as Microsoft .NET, whose System.DateTime type is by default serialized to JSON as in the following example:

    /Date(1302547608878)/

The number represents milliseconds since the Unix epoch.

Constructors

DotNetTime |
Fields fromDotNetTime :: UTCTime Acquire the underlying value.

Instances

Eq DotNetTime # |
Methods (==) :: DotNetTime -> DotNetTime -> Bool # (/=) :: DotNetTime -> DotNetTime -> Bool #
Ord DotNetTime # |
Methods compare :: DotNetTime -> DotNetTime -> Ordering # (<) :: DotNetTime -> DotNetTime -> Bool # (<=) :: DotNetTime -> DotNetTime -> Bool # (>) :: DotNetTime -> DotNetTime -> Bool # (>=) :: DotNetTime -> DotNetTime -> Bool # max :: DotNetTime -> DotNetTime -> DotNetTime # min :: DotNetTime -> DotNetTime -> DotNetTime #
Read DotNetTime # |
Methods readsPrec :: Int -> ReadS DotNetTime # readList :: ReadS [DotNetTime] # readPrec :: ReadPrec DotNetTime # readListPrec :: ReadPrec [DotNetTime] #
Show DotNetTime # |
Methods showsPrec :: Int -> DotNetTime -> ShowS # show :: DotNetTime -> String # showList :: [DotNetTime] -> ShowS #
FormatTime DotNetTime # |
Methods formatCharacter :: Char -> Maybe (TimeLocale -> Maybe NumericPadOption -> DotNetTime -> String) #
ToJSON DotNetTime # |
Methods toJSON :: DotNetTime -> Value # toEncoding :: DotNetTime -> Encoding # toJSONList :: [DotNetTime] -> Value # toEncodingList :: [DotNetTime] -> Encoding #
FromJSON DotNetTime # |
Methods parseJSON :: Value -> Parser DotNetTime # parseJSONList :: Value -> Parser [DotNetTime] #

# Type conversion

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:

- `empty` and `mzero` work, but are terse and uninformative;
- `fail` yields a custom error message;
- `typeMismatch` produces an informative message for cases when the value encountered is not of the expected type.

An example type and instance using `typeMismatch`:

    -- 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 mzero to fail, but typeMismatch
        -- gives a much more informative error message.
        parseJSON invalid    = typeMismatch "Coord" invalid

For this common case of only being concerned with a single type of JSON value, the functions `withObject`, `withNumber`, 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

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

Methods

parseJSON :: Value -> Parser a #

parseJSON :: (Generic a, GFromJSON Zero (Rep a)) => Value -> Parser a #

parseJSONList :: Value -> Parser [a] #

Instances

FromJSON Bool # |
Methods parseJSON :: Value -> Parser Bool # parseJSONList :: Value -> Parser [Bool] #
FromJSON Char # |
Methods parseJSON :: Value -> Parser Char # parseJSONList :: Value -> Parser [Char] #
FromJSON Double # |
Methods parseJSON :: Value -> Parser Double # parseJSONList :: Value -> Parser [Double] #
FromJSON Float # |
Methods parseJSON :: Value -> Parser Float # parseJSONList :: Value -> Parser [Float] #
FromJSON Int # |
Methods parseJSON :: Value -> Parser Int # parseJSONList :: Value -> Parser [Int] #
FromJSON Int8 # |
Methods parseJSON :: Value -> Parser Int8 # parseJSONList :: Value -> Parser [Int8] #
FromJSON Int16 # |
Methods parseJSON :: Value -> Parser Int16 # parseJSONList :: Value -> Parser [Int16] #
FromJSON Int32 # |
Methods parseJSON :: Value -> Parser Int32 # parseJSONList :: Value -> Parser [Int32] #
FromJSON Int64 # |
Methods parseJSON :: Value -> Parser Int64 # parseJSONList :: Value -> Parser [Int64] #
FromJSON Integer # | WARNING: Only parse Integers from trusted input since an attacker could easily fill up the memory of the target system by specifying a scientific number with a big exponent like `1e1000000000`.
Methods parseJSON :: Value -> Parser Integer # parseJSONList :: Value -> Parser [Integer] #
FromJSON Ordering # |
Methods parseJSON :: Value -> Parser Ordering # parseJSONList :: Value -> Parser [Ordering] #
FromJSON Word # |
Methods parseJSON :: Value -> Parser Word # parseJSONList :: Value -> Parser [Word] #
FromJSON Word8 # |
Methods parseJSON :: Value -> Parser Word8 # parseJSONList :: Value -> Parser [Word8] #
FromJSON Word16 # |
Methods parseJSON :: Value -> Parser Word16 # parseJSONList :: Value -> Parser [Word16] #
FromJSON Word32 # |
Methods parseJSON :: Value -> Parser Word32 # parseJSONList :: Value -> Parser [Word32] #
FromJSON Word64 # |
Methods parseJSON :: Value -> Parser Word64 # parseJSONList :: Value -> Parser [Word64] #
FromJSON () # |
Methods parseJSON :: Value -> Parser () # parseJSONList :: Value -> Parser [()] #
FromJSON Text # |
Methods parseJSON :: Value -> Parser Text # parseJSONList :: Value -> Parser [Text] #
FromJSON Text # |
Methods parseJSON :: Value -> Parser Text # parseJSONList :: Value -> Parser [Text] #
FromJSON Number # |
Methods parseJSON :: Value -> Parser Number # parseJSONList :: Value -> Parser [Number] #
FromJSON Natural # |
Methods parseJSON :: Value -> Parser Natural # parseJSONList :: Value -> Parser [Natural] #
FromJSON Version # |
Methods parseJSON :: Value -> Parser Version # parseJSONList :: Value -> Parser [Version] #
FromJSON IntSet # |
Methods parseJSON :: Value -> Parser IntSet # parseJSONList :: Value -> Parser [IntSet] #
FromJSON Scientific # |
Methods parseJSON :: Value -> Parser Scientific # parseJSONList :: Value -> Parser [Scientific] #
FromJSON LocalTime # |
Methods parseJSON :: Value -> Parser LocalTime # parseJSONList :: Value -> Parser [LocalTime] #
FromJSON ZonedTime # |
Methods parseJSON :: Value -> Parser ZonedTime # parseJSONList :: Value -> Parser [ZonedTime] #
FromJSON TimeOfDay # |
Methods parseJSON :: Value -> Parser TimeOfDay # parseJSONList :: Value -> Parser [TimeOfDay] #
FromJSON UTCTime # |
Methods parseJSON :: Value -> Parser UTCTime # parseJSONList :: Value -> Parser [UTCTime] #
FromJSON NominalDiffTime # | WARNING: Only parse lengths of time from trusted input since an attacker could easily fill up the memory of the target system by specifying a scientific number with a big exponent like `1e1000000000`.
Methods parseJSON :: Value -> Parser NominalDiffTime # parseJSONList :: Value -> Parser [NominalDiffTime] #
FromJSON Day # |
Methods parseJSON :: Value -> Parser Day # parseJSONList :: Value -> Parser [Day] #
FromJSON UUID # |
Methods parseJSON :: Value -> Parser UUID # parseJSONList :: Value -> Parser [UUID] #
FromJSON DotNetTime # |
Methods parseJSON :: Value -> Parser DotNetTime # parseJSONList :: Value -> Parser [DotNetTime] #
FromJSON Value # |
Methods parseJSON :: Value -> Parser Value # parseJSONList :: Value -> Parser [Value] #
FromJSON a => FromJSON [a] # |
Methods parseJSON :: Value -> Parser [a] # parseJSONList :: Value -> Parser [[a]] #
FromJSON a => FromJSON (Maybe a) # |
Methods parseJSON :: Value -> Parser (Maybe a) # parseJSONList :: Value -> Parser [Maybe a] #
(FromJSON a, Integral a) => FromJSON (Ratio a) # |
Methods parseJSON :: Value -> Parser (Ratio a) # parseJSONList :: Value -> Parser [Ratio a] #
FromJSON a => FromJSON (Identity a) # |
Methods parseJSON :: Value -> Parser (Identity a) # parseJSONList :: Value -> Parser [Identity a] #
FromJSON a => FromJSON (Min a) # |
Methods parseJSON :: Value -> Parser (Min a) # parseJSONList :: Value -> Parser [Min a] #
FromJSON a => FromJSON (Max a) # |
Methods parseJSON :: Value -> Parser (Max a) # parseJSONList :: Value -> Parser [Max a] #
FromJSON a => FromJSON (First a) # |
Methods parseJSON :: Value -> Parser (First a) # parseJSONList :: Value -> Parser [First a] #
FromJSON a => FromJSON (Last a) # |
Methods parseJSON :: Value -> Parser (Last a) # parseJSONList :: Value -> Parser [Last a] #
FromJSON a => FromJSON (WrappedMonoid a) # |
Methods parseJSON :: Value -> Parser (WrappedMonoid a) # parseJSONList :: Value -> Parser [WrappedMonoid a] #
FromJSON a => FromJSON (Option a) # |
Methods parseJSON :: Value -> Parser (Option a) # parseJSONList :: Value -> Parser [Option a] #
FromJSON a => FromJSON (NonEmpty a) # |
Methods parseJSON :: Value -> Parser (NonEmpty a) # parseJSONList :: Value -> Parser [NonEmpty a] #
HasResolution a => FromJSON (Fixed a) # | WARNING: Only parse fixed-precision numbers from trusted input since an attacker could easily fill up the memory of the target system by specifying a scientific number with a big exponent like `1e1000000000`.
Methods parseJSON :: Value -> Parser (Fixed a) # parseJSONList :: Value -> Parser [Fixed a] #
FromJSON a => FromJSON (Dual a) # |
Methods parseJSON :: Value -> Parser (Dual a) # parseJSONList :: Value -> Parser [Dual a] #
FromJSON a => FromJSON (First a) # |
Methods parseJSON :: Value -> Parser (First a) # parseJSONList :: Value -> Parser [First a] #
FromJSON a => FromJSON (Last a) # |
Methods parseJSON :: Value -> Parser (Last a) # parseJSONList :: Value -> Parser [Last a] #
FromJSON v => FromJSON (Tree v) # |
Methods parseJSON :: Value -> Parser (Tree v) # parseJSONList :: Value -> Parser [Tree v] #
FromJSON a => FromJSON (Seq a) # |
Methods parseJSON :: Value -> Parser (Seq a) # parseJSONList :: Value -> Parser [Seq a] #
FromJSON a => FromJSON (IntMap a) # |
Methods parseJSON :: Value -> Parser (IntMap a) # parseJSONList :: Value -> Parser [IntMap a] #
(Ord a, FromJSON a) => FromJSON (Set a) # |
Methods parseJSON :: Value -> Parser (Set a) # parseJSONList :: Value -> Parser [Set a] #
FromJSON a => FromJSON (DList a) # |
Methods parseJSON :: Value -> Parser (DList a) # parseJSONList :: Value -> Parser [DList a] #
(Eq a, Hashable a, FromJSON a) => FromJSON (HashSet a) # |
Methods parseJSON :: Value -> Parser (HashSet a) # parseJSONList :: Value -> Parser [HashSet a] #
FromJSON a => FromJSON (Vector a) # |
Methods parseJSON :: Value -> Parser (Vector a) # parseJSONList :: Value -> Parser [Vector a] #
(Vector Vector a, FromJSON a) => FromJSON (Vector a) # |
Methods parseJSON :: Value -> Parser (Vector a) # parseJSONList :: Value -> Parser [Vector a] #
(Storable a, FromJSON a) => FromJSON (Vector a) # |
Methods parseJSON :: Value -> Parser (Vector a) # parseJSONList :: Value -> Parser [Vector a] #
(Prim a, FromJSON a) => FromJSON (Vector a) # |
Methods parseJSON :: Value -> Parser (Vector a) # parseJSONList :: Value -> Parser [Vector a] #
(FromJSON a, FromJSON b) => FromJSON (Either a b) # |
Methods parseJSON :: Value -> Parser (Either a b) # parseJSONList :: Value -> Parser [Either a b] #
(FromJSON a, FromJSON b) => FromJSON (a, b) # |
Methods parseJSON :: Value -> Parser (a, b) # parseJSONList :: Value -> Parser [(a, b)] #
FromJSON (Proxy k a) # |
Methods parseJSON :: Value -> Parser (Proxy k a) # parseJSONList :: Value -> Parser [Proxy k a] #
(FromJSONKey k, Ord k, FromJSON v) => FromJSON (Map k v) # |
Methods parseJSON :: Value -> Parser (Map k v) # parseJSONList :: Value -> Parser [Map k v] #
(FromJSON v, FromJSONKey k, Eq k, Hashable k) => FromJSON (HashMap k v) # |
Methods parseJSON :: Value -> Parser (HashMap k v) # parseJSONList :: Value -> Parser [HashMap k v] #
(FromJSON a, FromJSON b, FromJSON c) => FromJSON (a, b, c) # |
Methods parseJSON :: Value -> Parser (a, b, c) # parseJSONList :: Value -> Parser [(a, b, c)] #
FromJSON a => FromJSON (Const k a b) # |
Methods parseJSON :: Value -> Parser (Const k a b) # parseJSONList :: Value -> Parser [Const k a b] #
FromJSON b => FromJSON (Tagged k a b) # |
Methods parseJSON :: Value -> Parser (Tagged k a b) # parseJSONList :: Value -> Parser [Tagged k a b] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d) => FromJSON (a, b, c, d) # |
Methods parseJSON :: Value -> Parser (a, b, c, d) # parseJSONList :: Value -> Parser [(a, b, c, d)] #
(FromJSON1 f, FromJSON1 g, FromJSON a) => FromJSON (Sum * f g a) # |
Methods parseJSON :: Value -> Parser (Sum * f g a) # parseJSONList :: Value -> Parser [Sum * f g a] #
(FromJSON1 f, FromJSON1 g, FromJSON a) => FromJSON (Product * f g a) # |
Methods parseJSON :: Value -> Parser (Product * f g a) # parseJSONList :: Value -> Parser [Product * f g a] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e) => FromJSON (a, b, c, d, e) # |
Methods parseJSON :: Value -> Parser (a, b, c, d, e) # parseJSONList :: Value -> Parser [(a, b, c, d, e)] #
(FromJSON1 f, FromJSON1 g, FromJSON a) => FromJSON (Compose * * f g a) # |
Methods parseJSON :: Value -> Parser (Compose * * f g a) # parseJSONList :: Value -> Parser [Compose * * f g a] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f) => FromJSON (a, b, c, d, e, f) # |
Methods parseJSON :: Value -> Parser (a, b, c, d, e, f) # parseJSONList :: Value -> Parser [(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) # |
Methods parseJSON :: Value -> Parser (a, b, c, d, e, f, g) # parseJSONList :: Value -> Parser [(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) # |
Methods parseJSON :: Value -> Parser (a, b, c, d, e, f, g, h) # parseJSONList :: Value -> Parser [(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) # |
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)] #
(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) # |
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)] #
(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) # |
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)] #
(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) # |
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)] #
(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) # |
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)] #
(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) # |
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)] #
(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) # |
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)] #

data Result a #

The result of running a `Parser`.

Constructors

Error String |
Success a |

Instances

Monad Result # |
Methods (>>=) :: Result a -> (a -> Result b) -> Result b # (>>) :: Result a -> Result b -> Result b # return :: a -> Result a # fail :: String -> Result a #
Functor Result # |
Methods fmap :: (a -> b) -> Result a -> Result b # (<$) :: a -> Result b -> Result a #
MonadFail Result # |
Methods fail :: String -> Result a #
Applicative Result # |
Methods pure :: a -> Result a # (<*>) :: Result (a -> b) -> Result a -> Result b # (*>) :: Result a -> Result b -> Result b # (<*) :: Result a -> Result b -> Result a #
Foldable Result # |
Methods fold :: Monoid m => Result m -> m # foldMap :: Monoid m => (a -> m) -> Result a -> m # foldr :: (a -> b -> b) -> b -> Result a -> b # foldr' :: (a -> b -> b) -> b -> Result a -> b # foldl :: (b -> a -> b) -> b -> Result a -> b # foldl' :: (b -> a -> b) -> b -> Result a -> b # foldr1 :: (a -> a -> a) -> Result a -> a # foldl1 :: (a -> a -> a) -> Result a -> a # toList :: Result a -> [a] # null :: Result a -> Bool # length :: Result a -> Int # elem :: Eq a => a -> Result a -> Bool # maximum :: Ord a => Result a -> a # minimum :: Ord a => Result a -> a # sum :: Num a => Result a -> a # product :: Num a => Result a -> a #
Traversable Result # |
Methods traverse :: Applicative f => (a -> f b) -> Result a -> f (Result b) # sequenceA :: Applicative f => Result (f a) -> f (Result a) # mapM :: Monad m => (a -> m b) -> Result a -> m (Result b) # sequence :: Monad m => Result (m a) -> m (Result a) #
Alternative Result # |
Methods empty :: Result a # (<|>) :: Result a -> Result a -> Result a # some :: Result a -> Result [a] # many :: Result a -> Result [a] #
MonadPlus Result # |
Methods mzero :: Result a # mplus :: Result a -> Result a -> Result a #
Eq a => Eq (Result a) # |
Methods (==) :: Result a -> Result a -> Bool # (/=) :: Result a -> Result a -> Bool #
Show a => Show (Result a) # |
Methods showsPrec :: Int -> Result a -> ShowS # show :: Result a -> String # showList :: [Result a] -> ShowS #
Semigroup (Result a) # |
Methods (<>) :: Result a -> Result a -> Result a # sconcat :: NonEmpty (Result a) -> Result a # stimes :: Integral b => b -> Result a -> Result a #
Monoid (Result a) # |
Methods mempty :: Result a # mappend :: Result a -> Result a -> Result a # mconcat :: [Result a] -> Result a #
NFData a => NFData (Result a) # |
Methods rnf :: Result a -> () #

fromJSON :: FromJSON a => Value -> Result a #

Convert a value from JSON, failing if the types do not match.

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

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 to reasons:

1. 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.
2. 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.)

Methods

toJSON :: a -> Value #

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

toJSON :: (Generic a, GToJSON Zero (Rep a)) => 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 #

Instances

ToJSON Bool # |
Methods toJSON :: Bool -> Value # toEncoding :: Bool -> Encoding # toJSONList :: [Bool] -> Value # toEncodingList :: [Bool] -> Encoding #
ToJSON Char # |
Methods toJSON :: Char -> Value # toEncoding :: Char -> Encoding # toJSONList :: [Char] -> Value # toEncodingList :: [Char] -> Encoding #
ToJSON Double # |
Methods toJSON :: Double -> Value # toEncoding :: Double -> Encoding # toJSONList :: [Double] -> Value # toEncodingList :: [Double] -> Encoding #
ToJSON Float # |
Methods toJSON :: Float -> Value # toEncoding :: Float -> Encoding # toJSONList :: [Float] -> Value # toEncodingList :: [Float] -> Encoding #
ToJSON Int # |
Methods toJSON :: Int -> Value # toEncoding :: Int -> Encoding # toJSONList :: [Int] -> Value # toEncodingList :: [Int] -> Encoding #
ToJSON Int8 # |
Methods toJSON :: Int8 -> Value # toEncoding :: Int8 -> Encoding # toJSONList :: [Int8] -> Value # toEncodingList :: [Int8] -> Encoding #
ToJSON Int16 # |
Methods toJSON :: Int16 -> Value # toEncoding :: Int16 -> Encoding # toJSONList :: [Int16] -> Value # toEncodingList :: [Int16] -> Encoding #
ToJSON Int32 # |
Methods toJSON :: Int32 -> Value # toEncoding :: Int32 -> Encoding # toJSONList :: [Int32] -> Value # toEncodingList :: [Int32] -> Encoding #
ToJSON Int64 # |
Methods toJSON :: Int64 -> Value # toEncoding :: Int64 -> Encoding # toJSONList :: [Int64] -> Value # toEncodingList :: [Int64] -> Encoding #
ToJSON Integer # |
Methods toJSON :: Integer -> Value # toEncoding :: Integer -> Encoding # toJSONList :: [Integer] -> Value # toEncodingList :: [Integer] -> Encoding #
ToJSON Ordering # |
Methods toJSON :: Ordering -> Value # toEncoding :: Ordering -> Encoding # toJSONList :: [Ordering] -> Value # toEncodingList :: [Ordering] -> Encoding #
ToJSON Word # |
Methods toJSON :: Word -> Value # toEncoding :: Word -> Encoding # toJSONList :: [Word] -> Value # toEncodingList :: [Word] -> Encoding #
ToJSON Word8 # |
Methods toJSON :: Word8 -> Value # toEncoding :: Word8 -> Encoding # toJSONList :: [Word8] -> Value # toEncodingList :: [Word8] -> Encoding #
ToJSON Word16 # |
Methods toJSON :: Word16 -> Value # toEncoding :: Word16 -> Encoding # toJSONList :: [Word16] -> Value # toEncodingList :: [Word16] -> Encoding #
ToJSON Word32 # |
Methods toJSON :: Word32 -> Value # toEncoding :: Word32 -> Encoding # toJSONList :: [Word32] -> Value # toEncodingList :: [Word32] -> Encoding #
ToJSON Word64 # |
Methods toJSON :: Word64 -> Value # toEncoding :: Word64 -> Encoding # toJSONList :: [Word64] -> Value # toEncodingList :: [Word64] -> Encoding #
ToJSON () # |
Methods toJSON :: () -> Value # toEncoding :: () -> Encoding # toJSONList :: [()] -> Value # toEncodingList :: [()] -> Encoding #
ToJSON Text # |
Methods toJSON :: Text -> Value # toEncoding :: Text -> Encoding # toJSONList :: [Text] -> Value # toEncodingList :: [Text] -> Encoding #
ToJSON Text # |
Methods toJSON :: Text -> Value # toEncoding :: Text -> Encoding # toJSONList :: [Text] -> Value # toEncodingList :: [Text] -> Encoding #
ToJSON Number # |
Methods toJSON :: Number -> Value # toEncoding :: Number -> Encoding # toJSONList :: [Number] -> Value # toEncodingList :: [Number] -> Encoding #
ToJSON Natural # |
Methods toJSON :: Natural -> Value # toEncoding :: Natural -> Encoding # toJSONList :: [Natural] -> Value # toEncodingList :: [Natural] -> Encoding #
ToJSON Version # |
Methods toJSON :: Version -> Value # toEncoding :: Version -> Encoding # toJSONList :: [Version] -> Value # toEncodingList :: [Version] -> Encoding #
ToJSON IntSet # |
Methods toJSON :: IntSet -> Value # toEncoding :: IntSet -> Encoding # toJSONList :: [IntSet] -> Value # toEncodingList :: [IntSet] -> Encoding #
ToJSON Scientific # |
Methods toJSON :: Scientific -> Value # toEncoding :: Scientific -> Encoding # toJSONList :: [Scientific] -> Value # toEncodingList :: [Scientific] -> Encoding #
ToJSON LocalTime # |
Methods toJSON :: LocalTime -> Value # toEncoding :: LocalTime -> Encoding # toJSONList :: [LocalTime] -> Value # toEncodingList :: [LocalTime] -> Encoding #
ToJSON ZonedTime # |
Methods toJSON :: ZonedTime -> Value # toEncoding :: ZonedTime -> Encoding # toJSONList :: [ZonedTime] -> Value # toEncodingList :: [ZonedTime] -> Encoding #
ToJSON TimeOfDay # |
Methods toJSON :: TimeOfDay -> Value # toEncoding :: TimeOfDay -> Encoding # toJSONList :: [TimeOfDay] -> Value # toEncodingList :: [TimeOfDay] -> Encoding #
ToJSON UTCTime # |
Methods toJSON :: UTCTime -> Value # toEncoding :: UTCTime -> Encoding # toJSONList :: [UTCTime] -> Value # toEncodingList :: [UTCTime] -> Encoding #
ToJSON NominalDiffTime # |
Methods toJSON :: NominalDiffTime -> Value # toEncoding :: NominalDiffTime -> Encoding # toJSONList :: [NominalDiffTime] -> Value # toEncodingList :: [NominalDiffTime] -> Encoding #
ToJSON Day # |
Methods toJSON :: Day -> Value # toEncoding :: Day -> Encoding # toJSONList :: [Day] -> Value # toEncodingList :: [Day] -> Encoding #
ToJSON UUID # |
Methods toJSON :: UUID -> Value # toEncoding :: UUID -> Encoding # toJSONList :: [UUID] -> Value # toEncodingList :: [UUID] -> Encoding #
ToJSON DotNetTime # |
Methods toJSON :: DotNetTime -> Value # toEncoding :: DotNetTime -> Encoding # toJSONList :: [DotNetTime] -> Value # toEncodingList :: [DotNetTime] -> Encoding #
ToJSON Value # |
Methods toJSON :: Value -> Value # toEncoding :: Value -> Encoding # toJSONList :: [Value] -> Value # toEncodingList :: [Value] -> Encoding #
ToJSON a => ToJSON [a] # |
Methods toJSON :: [a] -> Value # toEncoding :: [a] -> Encoding # toJSONList :: [[a]] -> Value # toEncodingList :: [[a]] -> Encoding #
ToJSON a => ToJSON (Maybe a) # |
Methods toJSON :: Maybe a -> Value # toEncoding :: Maybe a -> Encoding # toJSONList :: [Maybe a] -> Value # toEncodingList :: [Maybe a] -> Encoding #
(ToJSON a, Integral a) => ToJSON (Ratio a) # |
Methods toJSON :: Ratio a -> Value # toEncoding :: Ratio a -> Encoding # toJSONList :: [Ratio a] -> Value # toEncodingList :: [Ratio a] -> Encoding #
ToJSON a => ToJSON (Identity a) # |
Methods toJSON :: Identity a -> Value # toEncoding :: Identity a -> Encoding # toJSONList :: [Identity a] -> Value # toEncodingList :: [Identity a] -> Encoding #
ToJSON a => ToJSON (Min a) # |
Methods toJSON :: Min a -> Value # toEncoding :: Min a -> Encoding # toJSONList :: [Min a] -> Value # toEncodingList :: [Min a] -> Encoding #
ToJSON a => ToJSON (Max a) # |
Methods toJSON :: Max a -> Value # toEncoding :: Max a -> Encoding # toJSONList :: [Max a] -> Value # toEncodingList :: [Max a] -> Encoding #
ToJSON a => ToJSON (First a) # |
Methods toJSON :: First a -> Value # toEncoding :: First a -> Encoding # toJSONList :: [First a] -> Value # toEncodingList :: [First a] -> Encoding #
ToJSON a => ToJSON (Last a) # |
Methods toJSON :: Last a -> Value # toEncoding :: Last a -> Encoding # toJSONList :: [Last a] -> Value # toEncodingList :: [Last a] -> Encoding #
ToJSON a => ToJSON (WrappedMonoid a) # |
Methods toJSON :: WrappedMonoid a -> Value # toEncoding :: WrappedMonoid a -> Encoding # toJSONList :: [WrappedMonoid a] -> Value # toEncodingList :: [WrappedMonoid a] -> Encoding #
ToJSON a => ToJSON (Option a) # |
Methods toJSON :: Option a -> Value # toEncoding :: Option a -> Encoding # toJSONList :: [Option a] -> Value # toEncodingList :: [Option a] -> Encoding #
ToJSON a => ToJSON (NonEmpty a) # |
Methods toJSON :: NonEmpty a -> Value # toEncoding :: NonEmpty a -> Encoding # toJSONList :: [NonEmpty a] -> Value # toEncodingList :: [NonEmpty a] -> Encoding #
HasResolution a => ToJSON (Fixed a) # |
Methods toJSON :: Fixed a -> Value # toEncoding :: Fixed a -> Encoding # toJSONList :: [Fixed a] -> Value # toEncodingList :: [Fixed a] -> Encoding #
ToJSON a => ToJSON (Dual a) # |
Methods toJSON :: Dual a -> Value # toEncoding :: Dual a -> Encoding # toJSONList :: [Dual a] -> Value # toEncodingList :: [Dual a] -> Encoding #
ToJSON a => ToJSON (First a) # |
Methods toJSON :: First a -> Value # toEncoding :: First a -> Encoding # toJSONList :: [First a] -> Value # toEncodingList :: [First a] -> Encoding #
ToJSON a => ToJSON (Last a) # |
Methods toJSON :: Last a -> Value # toEncoding :: Last a -> Encoding # toJSONList :: [Last a] -> Value # toEncodingList :: [Last a] -> Encoding #
ToJSON v => ToJSON (Tree v) # |
Methods toJSON :: Tree v -> Value # toEncoding :: Tree v -> Encoding # toJSONList :: [Tree v] -> Value # toEncodingList :: [Tree v] -> Encoding #
ToJSON a => ToJSON (Seq a) # |
Methods toJSON :: Seq a -> Value # toEncoding :: Seq a -> Encoding # toJSONList :: [Seq a] -> Value # toEncodingList :: [Seq a] -> Encoding #
ToJSON a => ToJSON (IntMap a) # |
Methods toJSON :: IntMap a -> Value # toEncoding :: IntMap a -> Encoding # toJSONList :: [IntMap a] -> Value # toEncodingList :: [IntMap a] -> Encoding #
ToJSON a => ToJSON (Set a) # |
Methods toJSON :: Set a -> Value # toEncoding :: Set a -> Encoding # toJSONList :: [Set a] -> Value # toEncodingList :: [Set a] -> Encoding #
ToJSON a => ToJSON (DList a) # |
Methods toJSON :: DList a -> Value # toEncoding :: DList a -> Encoding # toJSONList :: [DList a] -> Value # toEncodingList :: [DList a] -> Encoding #
ToJSON a => ToJSON (HashSet a) # |
Methods toJSON :: HashSet a -> Value # toEncoding :: HashSet a -> Encoding # toJSONList :: [HashSet a] -> Value # toEncodingList :: [HashSet a] -> Encoding #
ToJSON a => ToJSON (Vector a) # |
Methods toJSON :: Vector a -> Value # toEncoding :: Vector a -> Encoding # toJSONList :: [Vector a] -> Value # toEncodingList :: [Vector a] -> Encoding #
(Vector Vector a, ToJSON a) => ToJSON (Vector a) # |
Methods toJSON :: Vector a -> Value # toEncoding :: Vector a -> Encoding # toJSONList :: [Vector a] -> Value # toEncodingList :: [Vector a] -> Encoding #
(Storable a, ToJSON a) => ToJSON (Vector a) # |
Methods toJSON :: Vector a -> Value # toEncoding :: Vector a -> Encoding # toJSONList :: [Vector a] -> Value # toEncodingList :: [Vector a] -> Encoding #
(Prim a, ToJSON a) => ToJSON (Vector a) # |
Methods toJSON :: Vector a -> Value # toEncoding :: Vector a -> Encoding # toJSONList :: [Vector a] -> Value # toEncodingList :: [Vector a] -> Encoding #
(ToJSON a, ToJSON b) => ToJSON (Either a b) # |
Methods toJSON :: Either a b -> Value # toEncoding :: Either a b -> Encoding # toJSONList :: [Either a b] -> Value # toEncodingList :: [Either a b] -> Encoding #
(ToJSON a, ToJSON b) => ToJSON (a, b) # |
Methods toJSON :: (a, b) -> Value # toEncoding :: (a, b) -> Encoding # toJSONList :: [(a, b)] -> Value # toEncodingList :: [(a, b)] -> Encoding #
ToJSON (Proxy k a) # |
Methods toJSON :: Proxy k a -> Value # toEncoding :: Proxy k a -> Encoding # toJSONList :: [Proxy k a] -> Value # toEncodingList :: [Proxy k a] -> Encoding #
(ToJSON v, ToJSONKey k) => ToJSON (Map k v) # |
Methods toJSON :: Map k v -> Value # toEncoding :: Map k v -> Encoding # toJSONList :: [Map k v] -> Value # toEncodingList :: [Map k v] -> Encoding #
(ToJSON v, ToJSONKey k) => ToJSON (HashMap k v) # |
Methods toJSON :: HashMap k v -> Value # toEncoding :: HashMap k v -> Encoding # toJSONList :: [HashMap k v] -> Value # toEncodingList :: [HashMap k v] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c) => ToJSON (a, b, c) # |
Methods toJSON :: (a, b, c) -> Value # toEncoding :: (a, b, c) -> Encoding # toJSONList :: [(a, b, c)] -> Value # toEncodingList :: [(a, b, c)] -> Encoding #
ToJSON a => ToJSON (Const k a b) # |
Methods toJSON :: Const k a b -> Value # toEncoding :: Const k a b -> Encoding # toJSONList :: [Const k a b] -> Value # toEncodingList :: [Const k a b] -> Encoding #
ToJSON b => ToJSON (Tagged k a b) # |
Methods toJSON :: Tagged k a b -> Value # toEncoding :: Tagged k a b -> Encoding # toJSONList :: [Tagged k a b] -> Value # toEncodingList :: [Tagged k a b] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d) => ToJSON (a, b, c, d) # |
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 #
(ToJSON1 f, ToJSON1 g, ToJSON a) => ToJSON (Sum * f g a) # |
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 #
(ToJSON1 f, ToJSON1 g, ToJSON a) => ToJSON (Product * f g a) # |
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 #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e) => ToJSON (a, b, c, d, e) # |
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 #
(ToJSON1 f, ToJSON1 g, ToJSON a) => ToJSON (Compose * * f g a) # |
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 #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f) => ToJSON (a, b, c, d, e, f) # |
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 #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g) => ToJSON (a, b, c, d, e, f, g) # |
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 #
(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) # |
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 #
(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) # |
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 #
(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) # |
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 #
(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) # |
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 #
(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) # |
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 #
(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) # |
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 #
(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) # |
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 #
(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) # |
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 #

class KeyValue kv where #

A key-value pair for encoding a JSON object.

Minimal complete definition

(.=)

Methods

(.=) :: ToJSON v => Text -> v -> kv infixr 8 #

Instances

KeyValue Pair # |
Methods (.=) :: ToJSON v => Text -> v -> Pair #
KeyValue Series # |
Methods (.=) :: ToJSON v => Text -> v -> Series #

## Keys for maps

class ToJSONKey a where #

Typeclass for types that can be used as the key of a map-like container (like `Map` or `HashMap`). For example, since `Text` has a `ToJSONKey` instance and `Char` has a `ToJSON` instance, we can encode a value of type `Map` `Text` `Char`:

    >>> LBC8.putStrLn $ encode $ Map.fromList [("foo" :: Text, 'a')]
    {"foo":"a"}

Since `Int` also has a `ToJSONKey` instance, we can similarly write:

    >>> LBC8.putStrLn $ encode $ Map.fromList [(5 :: Int, 'a')]
    {"5":"a"}

JSON documents only accept strings as object keys. For any type from `base` that has a natural textual representation, it can be expected that its `ToJSONKey` instance will choose that representation.

For data types that lack a natural textual representation, an alternative is provided. The map-like container is represented as a JSON array instead of a JSON object. Each value in the array is an array with exactly two values. The first is the key and the second is the value.

For example, values of type '[Text]' cannot be encoded to a string, so a `Map` with keys of type '[Text]' is encoded as follows:

    >>> LBC8.putStrLn $ encode $ Map.fromList [(["foo","bar","baz" :: Text], 'a')]
    [[["foo","bar","baz"],"a"]]

The default implementation of `ToJSONKey` chooses this method of encoding a key, using the `ToJSON` instance of the type.

To use your own data type as the key in a map, all that is needed is to write a `ToJSONKey` (and possibly a `FromJSONKey`) instance for it. If the type cannot be trivially converted to and from `Text`, it is recommended that `ToJSONKeyValue` is used. Since the default implementations of the typeclass methods can build this from a `ToJSON` instance, there is nothing that needs to be written:

    data Foo = Foo { fooAge :: Int, fooName :: Text }
      deriving (Eq,Ord,Generic)
    instance ToJSON Foo
    instance ToJSONKey Foo

That's it. We can now write:

    >>> let m = Map.fromList [(Foo 4 "bar",'a'),(Foo 6 "arg",'b')]
    >>> LBC8.putStrLn $ encode m
    [[{"fooName":"bar","fooAge":4},"a"],[{"fooName":"arg","fooAge":6},"b"]]

The next case to consider is if we have a type that is a newtype wrapper around `Text`. The recommended approach is to use generalized newtype deriving:

    newtype RecordId = RecordId { getRecordId :: Text}
      deriving (Eq,Ord,ToJSONKey)

Then we may write:

    >>> LBC8.putStrLn $ encode $ Map.fromList [(RecordId "abc",'a')]
    {"abc":"a"}

Simple sum types are a final case worth considering. Suppose we have:

    data Color = Red | Green | Blue
      deriving (Show,Read,Eq,Ord)

It is possible to get the `ToJSONKey` instance for free as we did with `Foo`. However, in this case, we have a natural way to go to and from `Text` that does not require any escape sequences. So, in this example, `ToJSONKeyText` will be used instead of `ToJSONKeyValue`. The `Show` instance can be used to help write `ToJSONKey`:

    instance ToJSONKey Color where
      toJSONKey = ToJSONKeyText f g
        where f = Text.pack . show
              g = text . Text.pack . show
              -- text function is from Data.Aeson.Encoding

The situation of needing to turning function `a -> Text` into a `ToJSONKeyFunction` is common enough that a special combinator is provided for it. The above instance can be rewritten as:

    instance ToJSONKey Color where
      toJSONKey = toJSONKeyText (Text.pack . show)

The performance of the above instance can be improved by not using `String` as an intermediate step when converting to `Text`. One option for improving performance would be to use template haskell machinery from the `text-show` package. However, even with the approach, the `Encoding` (a wrapper around a bytestring builder) is generated by encoding the `Text` to a `ByteString`, an intermediate step that could be avoided. The fastest possible implementation would be:

    -- Assuming that OverloadedStrings is enabled
    instance ToJSONKey Color where
      toJSONKey = ToJSONKeyText f g
        where f x = case x of {Red -> "Red";Green ->"Green";Blue -> "Blue"}
              g x = case x of {Red -> text "Red";Green -> text "Green";Blue -> text "Blue"}
              -- text function is from Data.Aeson.Encoding

This works because GHC can lift the encoded values out of the case statements, which means that they are only evaluated once. This approach should only be used when there is a serious need to maximize performance.

Methods

toJSONKey :: ToJSONKeyFunction a #

Strategy for rendering the key for a map-like container.

toJSONKey :: ToJSON a => ToJSONKeyFunction a #

Strategy for rendering the key for a map-like container.

toJSONKeyList :: ToJSONKeyFunction [a] #

This is similar in spirit to the `showsList` method of `Show`. It makes it possible to give `String` keys special treatment without using `OverlappingInstances`. End users should always be able to use the default implementation of this method.

toJSONKeyList :: ToJSON a => ToJSONKeyFunction [a] #

This is similar in spirit to the `showsList` method of `Show`. It makes it possible to give `String` keys special treatment without using `OverlappingInstances`. End users should always be able to use the default implementation of this method.

Instances

ToJSONKey Bool # |
Methods toJSONKey :: ToJSONKeyFunction Bool # toJSONKeyList :: ToJSONKeyFunction [Bool] #
ToJSONKey Char # |
Methods toJSONKey :: ToJSONKeyFunction Char # toJSONKeyList :: ToJSONKeyFunction [Char] #
ToJSONKey Double # |
Methods toJSONKey :: ToJSONKeyFunction Double # toJSONKeyList :: ToJSONKeyFunction [Double] #
ToJSONKey Float # |
Methods toJSONKey :: ToJSONKeyFunction Float # toJSONKeyList :: ToJSONKeyFunction [Float] #
ToJSONKey Int # |
Methods toJSONKey :: ToJSONKeyFunction Int # toJSONKeyList :: ToJSONKeyFunction [Int] #
ToJSONKey Int8 # |
Methods toJSONKey :: ToJSONKeyFunction Int8 # toJSONKeyList :: ToJSONKeyFunction [Int8] #
ToJSONKey Int16 # |
Methods toJSONKey :: ToJSONKeyFunction Int16 # toJSONKeyList :: ToJSONKeyFunction [Int16] #
ToJSONKey Int32 # |
Methods toJSONKey :: ToJSONKeyFunction Int32 # toJSONKeyList :: ToJSONKeyFunction [Int32] #
ToJSONKey Int64 # |
Methods toJSONKey :: ToJSONKeyFunction Int64 # toJSONKeyList :: ToJSONKeyFunction [Int64] #
ToJSONKey Integer # |
Methods toJSONKey :: ToJSONKeyFunction Integer # toJSONKeyList :: ToJSONKeyFunction [Integer] #
ToJSONKey Word # |
Methods toJSONKey :: ToJSONKeyFunction Word # toJSONKeyList :: ToJSONKeyFunction [Word] #
ToJSONKey Word8 # |
Methods toJSONKey :: ToJSONKeyFunction Word8 # toJSONKeyList :: ToJSONKeyFunction [Word8] #
ToJSONKey Word16 # |
Methods toJSONKey :: ToJSONKeyFunction Word16 # toJSONKeyList :: ToJSONKeyFunction [Word16] #
ToJSONKey Word32 # |
Methods toJSONKey :: ToJSONKeyFunction Word32 # toJSONKeyList :: ToJSONKeyFunction [Word32] #
ToJSONKey Word64 # |
Methods toJSONKey :: ToJSONKeyFunction Word64 # toJSONKeyList :: ToJSONKeyFunction [Word64] #
ToJSONKey Text # |
Methods toJSONKey :: ToJSONKeyFunction Text # toJSONKeyList :: ToJSONKeyFunction [Text] #
ToJSONKey Text # |
Methods toJSONKey :: ToJSONKeyFunction Text # toJSONKeyList :: ToJSONKeyFunction [Text] #
ToJSONKey Natural # |
Methods toJSONKey :: ToJSONKeyFunction Natural # toJSONKeyList :: ToJSONKeyFunction [Natural] #
ToJSONKey Version # |
Methods toJSONKey :: ToJSONKeyFunction Version # toJSONKeyList :: ToJSONKeyFunction [Version] #
ToJSONKey Scientific # |
Methods toJSONKey :: ToJSONKeyFunction Scientific # toJSONKeyList :: ToJSONKeyFunction [Scientific] #
ToJSONKey LocalTime # |
Methods toJSONKey :: ToJSONKeyFunction LocalTime # toJSONKeyList :: ToJSONKeyFunction [LocalTime] #
ToJSONKey ZonedTime # |
Methods toJSONKey :: ToJSONKeyFunction ZonedTime # toJSONKeyList :: ToJSONKeyFunction [ZonedTime] #
ToJSONKey TimeOfDay # |
Methods toJSONKey :: ToJSONKeyFunction TimeOfDay # toJSONKeyList :: ToJSONKeyFunction [TimeOfDay] #
ToJSONKey UTCTime # |
Methods toJSONKey :: ToJSONKeyFunction UTCTime # toJSONKeyList :: ToJSONKeyFunction [UTCTime] #
ToJSONKey Day # |
Methods toJSONKey :: ToJSONKeyFunction Day # toJSONKeyList :: ToJSONKeyFunction [Day] #
ToJSONKey UUID # |
Methods toJSONKey :: ToJSONKeyFunction UUID # toJSONKeyList :: ToJSONKeyFunction [UUID] #
(ToJSONKey a, ToJSON a) => ToJSONKey [a] # |
Methods toJSONKey :: ToJSONKeyFunction [a] # toJSONKeyList :: ToJSONKeyFunction [[a]] #
ToJSONKey a => ToJSONKey (Identity a) # |
Methods toJSONKey :: ToJSONKeyFunction (Identity a) # toJSONKeyList :: ToJSONKeyFunction [Identity a] #
HasResolution a => ToJSONKey (Fixed a) # |
Methods toJSONKey :: ToJSONKeyFunction (Fixed a) # toJSONKeyList :: ToJSONKeyFunction [Fixed a] #
(ToJSON a, ToJSON b) => ToJSONKey (a, b) # |
Methods toJSONKey :: ToJSONKeyFunction (a, b) # toJSONKeyList :: ToJSONKeyFunction [(a, b)] #
(ToJSON a, ToJSON b, ToJSON c) => ToJSONKey (a, b, c) # |
Methods toJSONKey :: ToJSONKeyFunction (a, b, c) # toJSONKeyList :: ToJSONKeyFunction [(a, b, c)] #
ToJSONKey b => ToJSONKey (Tagged k a b) # |
Methods toJSONKey :: ToJSONKeyFunction (Tagged k a b) # toJSONKeyList :: ToJSONKeyFunction [Tagged k a b] #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d) => ToJSONKey (a, b, c, d) # |
Methods toJSONKey :: ToJSONKeyFunction (a, b, c, d) # toJSONKeyList :: ToJSONKeyFunction [(a, b, c, d)] #

data ToJSONKeyFunction a #

Constructors

ToJSONKeyText !(a -> Text) !(a -> Encoding' Text) | key is encoded to string, produces object
ToJSONKeyValue !(a -> Value) !(a -> Encoding) | key is encoded to value, produces array

class FromJSONKey a where #

Read the docs for `ToJSONKey` first. This class is a conversion in the opposite direction. If you have a newtype wrapper around `Text`, the recommended way to define instances is with generalized newtype deriving:

    newtype SomeId = SomeId { getSomeId :: Text }
      deriving (Eq,Ord,Hashable,FromJSONKey)

Methods

fromJSONKey :: FromJSONKeyFunction a #

Strategy for parsing the key of a map-like container.

fromJSONKey :: FromJSON a => FromJSONKeyFunction a #

Strategy for parsing the key of a map-like container.

fromJSONKeyList :: FromJSONKeyFunction [a] #

This is similar in spirit to the `readList` method of `Read`. It makes it possible to give `String` keys special treatment without using `OverlappingInstances`. End users should always be able to use the default implementation of this method.

fromJSONKeyList :: FromJSON a => FromJSONKeyFunction [a] #

This is similar in spirit to the `readList` method of `Read`. It makes it possible to give `String` keys special treatment without using `OverlappingInstances`. End users should always be able to use the default implementation of this method.

Instances

FromJSONKey Bool # |
Methods fromJSONKey :: FromJSONKeyFunction Bool # fromJSONKeyList :: FromJSONKeyFunction [Bool] #
FromJSONKey Char # |
Methods fromJSONKey :: FromJSONKeyFunction Char # fromJSONKeyList :: FromJSONKeyFunction [Char] #
FromJSONKey Double # |
Methods fromJSONKey :: FromJSONKeyFunction Double # fromJSONKeyList :: FromJSONKeyFunction [Double] #
FromJSONKey Float # |
Methods fromJSONKey :: FromJSONKeyFunction Float # fromJSONKeyList :: FromJSONKeyFunction [Float] #
FromJSONKey Int # |
Methods fromJSONKey :: FromJSONKeyFunction Int # fromJSONKeyList :: FromJSONKeyFunction [Int] #
FromJSONKey Int8 # |
Methods fromJSONKey :: FromJSONKeyFunction Int8 # fromJSONKeyList :: FromJSONKeyFunction [Int8] #
FromJSONKey Int16 # |
Methods fromJSONKey :: FromJSONKeyFunction Int16 # fromJSONKeyList :: FromJSONKeyFunction [Int16] #
FromJSONKey Int32 # |
Methods fromJSONKey :: FromJSONKeyFunction Int32 # fromJSONKeyList :: FromJSONKeyFunction [Int32] #
FromJSONKey Int64 # |
Methods fromJSONKey :: FromJSONKeyFunction Int64 # fromJSONKeyList :: FromJSONKeyFunction [Int64] #
FromJSONKey Integer # |
Methods fromJSONKey :: FromJSONKeyFunction Integer # fromJSONKeyList :: FromJSONKeyFunction [Integer] #
FromJSONKey Word # |
Methods fromJSONKey :: FromJSONKeyFunction Word # fromJSONKeyList :: FromJSONKeyFunction [Word] #
FromJSONKey Word8 # |
Methods fromJSONKey :: FromJSONKeyFunction Word8 # fromJSONKeyList :: FromJSONKeyFunction [Word8] #
FromJSONKey Word16 # |
Methods fromJSONKey :: FromJSONKeyFunction Word16 # fromJSONKeyList :: FromJSONKeyFunction [Word16] #
FromJSONKey Word32 # |
Methods fromJSONKey :: FromJSONKeyFunction Word32 # fromJSONKeyList :: FromJSONKeyFunction [Word32] #
FromJSONKey Word64 # |
Methods fromJSONKey :: FromJSONKeyFunction Word64 # fromJSONKeyList :: FromJSONKeyFunction [Word64] #
FromJSONKey Text # |
Methods fromJSONKey :: FromJSONKeyFunction Text # fromJSONKeyList :: FromJSONKeyFunction [Text] #
FromJSONKey Text # |
Methods fromJSONKey :: FromJSONKeyFunction Text # fromJSONKeyList :: FromJSONKeyFunction [Text] #
FromJSONKey Natural # |
Methods fromJSONKey :: FromJSONKeyFunction Natural # fromJSONKeyList :: FromJSONKeyFunction [Natural] #
FromJSONKey Version # |
Methods fromJSONKey :: FromJSONKeyFunction Version # fromJSONKeyList :: FromJSONKeyFunction [Version] #
FromJSONKey LocalTime # |
Methods fromJSONKey :: FromJSONKeyFunction LocalTime # fromJSONKeyList :: FromJSONKeyFunction [LocalTime] #
FromJSONKey ZonedTime # |
Methods fromJSONKey :: FromJSONKeyFunction ZonedTime # fromJSONKeyList :: FromJSONKeyFunction [ZonedTime] #
FromJSONKey TimeOfDay # |
Methods fromJSONKey :: FromJSONKeyFunction TimeOfDay # fromJSONKeyList :: FromJSONKeyFunction [TimeOfDay] #
FromJSONKey UTCTime # |
Methods fromJSONKey :: FromJSONKeyFunction UTCTime # fromJSONKeyList :: FromJSONKeyFunction [UTCTime] #
FromJSONKey Day # |
Methods fromJSONKey :: FromJSONKeyFunction Day # fromJSONKeyList :: FromJSONKeyFunction [Day] #
FromJSONKey UUID # |
Methods fromJSONKey :: FromJSONKeyFunction UUID # fromJSONKeyList :: FromJSONKeyFunction [UUID] #
(FromJSONKey a, FromJSON a) => FromJSONKey [a] # |
Methods fromJSONKey :: FromJSONKeyFunction [a] # fromJSONKeyList :: FromJSONKeyFunction [[a]] #
FromJSONKey a => FromJSONKey (Identity a) # |
Methods fromJSONKey :: FromJSONKeyFunction (Identity a) # fromJSONKeyList :: FromJSONKeyFunction [Identity a] #
(FromJSON a, FromJSON b) => FromJSONKey (a, b) # |
Methods fromJSONKey :: FromJSONKeyFunction (a, b) # fromJSONKeyList :: FromJSONKeyFunction [(a, b)] #
(FromJSON a, FromJSON b, FromJSON c) => FromJSONKey (a, b, c) # |
Methods fromJSONKey :: FromJSONKeyFunction (a, b, c) # fromJSONKeyList :: FromJSONKeyFunction [(a, b, c)] #
FromJSONKey b => FromJSONKey (Tagged k a b) # |
Methods fromJSONKey :: FromJSONKeyFunction (Tagged k a b) # fromJSONKeyList :: FromJSONKeyFunction [Tagged k a b] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d) => FromJSONKey (a, b, c, d) # |
Methods fromJSONKey :: FromJSONKeyFunction (a, b, c, d) # fromJSONKeyList :: FromJSONKeyFunction [(a, b, c, d)] #

data FromJSONKeyFunction a #

This type is related to `ToJSONKeyFunction`. If `FromJSONKeyValue` is used in the `FromJSONKey` instance, then `ToJSONKeyValue` should be used in the `ToJSONKey` instance. The other three data constructors for this type all correspond to `ToJSONKeyText`. Strictly speaking, `FromJSONKeyTextParser` is more powerful than `FromJSONKeyText`, which is in turn more powerful than `FromJSONKeyCoerce`. For performance reasons, these exist as three options instead of one.

Constructors

FromJSONKeyCoerce !(CoerceText a) | uses `coerce` (`unsafeCoerce` in older GHCs)
FromJSONKeyText !(Text -> a) | conversion from `Text` that always succeeds
FromJSONKeyTextParser !(Text -> Parser a) | conversion from `Text` that may fail
FromJSONKeyValue !(Value -> Parser a) | conversion for non-textual keys

Instances

Functor FromJSONKeyFunction # | Only law abiding up to interpretation
Methods fmap :: (a -> b) -> FromJSONKeyFunction a -> FromJSONKeyFunction b # (<$) :: a -> FromJSONKeyFunction b -> FromJSONKeyFunction a #

## Liftings to unary and binary type constructors

class FromJSON1 f where #

Lifting of the `FromJSON` class to unary type constructors.

Instead of manually writing your `FromJSON1` 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 `liftParseJSON`.

To use the second, simply add a `deriving `Generic1`` clause to your datatype and declare a `FromJSON1` instance for your datatype without giving a definition for `liftParseJSON`.

For example:

    {-# LANGUAGE DeriveGeneric #-}

    import GHC.Generics

    data Pair a b = Pair { pairFst :: a, pairSnd :: b } deriving Generic1

    instance FromJSON a => FromJSON1 (Pair a)

If the default implementation doesn't give exactly the results you want, you can customize the generic decoding with only a tiny amount of effort, using `genericLiftParseJSON` with your preferred `Options`:

    customOptions = defaultOptions
                    { fieldLabelModifier = map toUpper
                    }

    instance FromJSON a => FromJSON1 (Pair a) where
        liftParseJSON = genericLiftParseJSON customOptions

Methods

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

liftParseJSON :: (Generic1 f, GFromJSON One (Rep1 f)) => (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (f a) #

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

Instances

FromJSON1 [] # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [a] # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [[a]] #
FromJSON1 Maybe # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (Maybe a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [Maybe a] #
FromJSON1 Identity # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (Identity a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [Identity a] #
FromJSON1 Min # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (Min a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [Min a] #
FromJSON1 Max # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (Max a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [Max a] #
FromJSON1 First # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (First a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [First a] #
FromJSON1 Last # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (Last a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [Last a] #
FromJSON1 WrappedMonoid # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (WrappedMonoid a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [WrappedMonoid a] #
FromJSON1 Option # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (Option a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [Option a] #
FromJSON1 NonEmpty # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (NonEmpty a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [NonEmpty a] #
FromJSON1 Dual # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (Dual a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [Dual a] #
FromJSON1 First # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (First a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [First a] #
FromJSON1 Last # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (Last a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [Last a] #
FromJSON1 Tree # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (Tree a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [Tree a] #
FromJSON1 Seq # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (Seq a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [Seq a] #
FromJSON1 IntMap # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (IntMap a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [IntMap a] #
FromJSON1 DList # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (DList a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [DList a] #
FromJSON1 Vector # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (Vector a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [Vector a] #
FromJSON a => FromJSON1 (Either a) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (Either a a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [Either a a] #
FromJSON a => FromJSON1 ((,) a) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (a, a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [(a, a)] #
FromJSON1 (Proxy *) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (Proxy * a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [Proxy * a] #
(FromJSONKey k, Ord k) => FromJSON1 (Map k) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (Map k a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [Map k a] #
(FromJSONKey k, Eq k, Hashable k) => FromJSON1 (HashMap k) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (HashMap k a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [HashMap k a] #
(FromJSON a, FromJSON b) => FromJSON1 ((,,) a b) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (a, b, a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [(a, b, a)] #
FromJSON a => FromJSON1 (Const * a) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (Const * a a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [Const * a a] #
FromJSON1 (Tagged k a) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (Tagged k a a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [Tagged k a a] #
(FromJSON a, FromJSON b, FromJSON c) => FromJSON1 ((,,,) a b c) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (a, b, c, a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [(a, b, c, a)] #
(FromJSON1 f, FromJSON1 g) => FromJSON1 (Sum * f g) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (Sum * f g a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [Sum * f g a] #
(FromJSON1 f, FromJSON1 g) => FromJSON1 (Product * f g) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (Product * f g a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [Product * f g a] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d) => FromJSON1 ((,,,,) a b c d) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (a, b, c, d, a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [(a, b, c, d, a)] #
(FromJSON1 f, FromJSON1 g) => FromJSON1 (Compose * * f g) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (Compose * * f g a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [Compose * * f g a] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e) => FromJSON1 ((,,,,,) a b c d e) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (a, b, c, d, e, a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [(a, b, c, d, e, a)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f) => FromJSON1 ((,,,,,,) a b c d e f) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (a, b, c, d, e, f, a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [(a, b, c, d, e, f, a)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g) => FromJSON1 ((,,,,,,,) a b c d e f g) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (a, b, c, d, e, f, g, a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [(a, b, c, d, e, f, g, a)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h) => FromJSON1 ((,,,,,,,,) a b c d e f g h) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (a, b, c, d, e, f, g, h, a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [(a, b, c, d, e, f, g, h, a)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i) => FromJSON1 ((,,,,,,,,,) a b c d e f g h i) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (a, b, c, d, e, f, g, h, i, a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [(a, b, c, d, e, f, g, h, i, a)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j) => FromJSON1 ((,,,,,,,,,,) a b c d e f g h i j) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (a, b, c, d, e, f, g, h, i, j, a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [(a, b, c, d, e, f, g, h, i, j, a)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j, FromJSON k) => FromJSON1 ((,,,,,,,,,,,) a b c d e f g h i j k) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (a, b, c, d, e, f, g, h, i, j, k, a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [(a, b, c, d, e, f, g, h, i, j, k, a)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j, FromJSON k, FromJSON l) => FromJSON1 ((,,,,,,,,,,,,) a b c d e f g h i j k l) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (a, b, c, d, e, f, g, h, i, j, k, l, a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [(a, b, c, d, e, f, g, h, i, j, k, l, a)] #
(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) => FromJSON1 ((,,,,,,,,,,,,,) a b c d e f g h i j k l m) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (a, b, c, d, e, f, g, h, i, j, k, l, m, a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [(a, b, c, d, e, f, g, h, i, j, k, l, m, a)] #
(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) => FromJSON1 ((,,,,,,,,,,,,,,) a b c d e f g h i j k l m n) # |
Methods liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (a, b, c, d, e, f, g, h, i, j, k, l, m, n, a) # liftParseJSONList :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [(a, b, c, d, e, f, g, h, i, j, k, l, m, n, a)] #

parseJSON1 :: (FromJSON1 f, FromJSON a) => Value -> Parser (f a) #

Lift the standard `parseJSON` function through the type constructor.

class FromJSON2 f where #

Lifting of the `FromJSON` class to binary type constructors.

Instead of manually writing your `FromJSON2` instance, Data.Aeson.TH provides Template Haskell functions which will derive an instance at compile time.

Minimal complete definition

liftParseJSON2

Methods

liftParseJSON2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser (f a b) #

liftParseJSONList2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser [f a b] #

Instances

FromJSON2 Either # |
Methods liftParseJSON2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser (Either a b) # liftParseJSONList2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser [Either a b] #
FromJSON2 (,) # |
Methods liftParseJSON2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser (a, b) # liftParseJSONList2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser [(a, b)] #
FromJSON a => FromJSON2 ((,,) a) # |
Methods liftParseJSON2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser (a, a, b) # liftParseJSONList2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser [(a, a, b)] #
FromJSON2 (Const *) # |
Methods liftParseJSON2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser (Const * a b) # liftParseJSONList2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser [Const * a b] #
FromJSON2 (Tagged *) # |
Methods liftParseJSON2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser (Tagged * a b) # liftParseJSONList2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser [Tagged * a b] #
(FromJSON a, FromJSON b) => FromJSON2 ((,,,) a b) # |
Methods liftParseJSON2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser (a, b, a, b) # liftParseJSONList2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser [(a, b, a, b)] #
(FromJSON a, FromJSON b, FromJSON c) => FromJSON2 ((,,,,) a b c) # |
Methods liftParseJSON2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser (a, b, c, a, b) # liftParseJSONList2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser [(a, b, c, a, b)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d) => FromJSON2 ((,,,,,) a b c d) # |
Methods liftParseJSON2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser (a, b, c, d, a, b) # liftParseJSONList2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser [(a, b, c, d, a, b)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e) => FromJSON2 ((,,,,,,) a b c d e) # |
Methods liftParseJSON2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser (a, b, c, d, e, a, b) # liftParseJSONList2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser [(a, b, c, d, e, a, b)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f) => FromJSON2 ((,,,,,,,) a b c d e f) # |
Methods liftParseJSON2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser (a, b, c, d, e, f, a, b) # liftParseJSONList2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser [(a, b, c, d, e, f, a, b)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g) => FromJSON2 ((,,,,,,,,) a b c d e f g) # |
Methods liftParseJSON2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser (a, b, c, d, e, f, g, a, b) # liftParseJSONList2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser [(a, b, c, d, e, f, g, a, b)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h) => FromJSON2 ((,,,,,,,,,) a b c d e f g h) # |
Methods liftParseJSON2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser (a, b, c, d, e, f, g, h, a, b) # liftParseJSONList2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser [(a, b, c, d, e, f, g, h, a, b)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i) => FromJSON2 ((,,,,,,,,,,) a b c d e f g h i) # |
Methods liftParseJSON2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser (a, b, c, d, e, f, g, h, i, a, b) # liftParseJSONList2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser [(a, b, c, d, e, f, g, h, i, a, b)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j) => FromJSON2 ((,,,,,,,,,,,) a b c d e f g h i j) # |
Methods liftParseJSON2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser (a, b, c, d, e, f, g, h, i, j, a, b) # liftParseJSONList2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser [(a, b, c, d, e, f, g, h, i, j, a, b)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j, FromJSON k) => FromJSON2 ((,,,,,,,,,,,,) a b c d e f g h i j k) # |
Methods liftParseJSON2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser (a, b, c, d, e, f, g, h, i, j, k, a, b) # liftParseJSONList2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser [(a, b, c, d, e, f, g, h, i, j, k, a, b)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j, FromJSON k, FromJSON l) => FromJSON2 ((,,,,,,,,,,,,,) a b c d e f g h i j k l) # |
Methods liftParseJSON2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser (a, b, c, d, e, f, g, h, i, j, k, l, a, b) # liftParseJSONList2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser [(a, b, c, d, e, f, g, h, i, j, k, l, a, b)] #
(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) => FromJSON2 ((,,,,,,,,,,,,,,) a b c d e f g h i j k l m) # |
Methods liftParseJSON2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser (a, b, c, d, e, f, g, h, i, j, k, l, m, a, b) # liftParseJSONList2 :: (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser [(a, b, c, d, e, f, g, h, i, j, k, l, m, a, b)] #

parseJSON2 :: (FromJSON2 f, FromJSON a, FromJSON b) => Value -> Parser (f a b) #

Lift the standard `parseJSON` function through the type constructor.

class ToJSON1 f where #

Lifting of the `ToJSON` class to unary type constructors.

Instead of manually writing your `ToJSON1` 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 `toJSON1`.

To use the second, simply add a `deriving `Generic1`` clause to your datatype and declare a `ToJSON1` instance for your datatype without giving definitions for `liftToJSON` or `liftToEncoding`.

For example:

    {-# LANGUAGE DeriveGeneric #-}

    import GHC.Generics

    data Pair = Pair { pairFst :: a, pairSnd :: b } deriving Generic1

    instance ToJSON a => ToJSON1 (Pair a)

If the default implementation doesn't give exactly the results you want, you can customize the generic encoding with only a tiny amount of effort, using `genericLiftToJSON` and `genericLiftToEncoding` with your preferred `Options`:

    customOptions = defaultOptions
                    { fieldLabelModifier = map toUpper
                    }

    instance ToJSON a => ToJSON1 (Pair a) where
        liftToJSON     = genericLiftToJSON customOptions
        liftToEncoding = genericLiftToEncoding customOptions

See also `ToJSON`.

Methods

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

liftToJSON :: (Generic1 f, GToJSON One (Rep1 f)) => (a -> Value) -> ([a] -> Value) -> f a -> Value #

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

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

liftToEncoding :: (Generic1 f, GToEncoding One (Rep1 f)) => (a -> Encoding) -> ([a] -> Encoding) -> f a -> Encoding #

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

Instances

ToJSON1 [] # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> [a] -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [[a]] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> [a] -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [[a]] -> Encoding #
ToJSON1 Maybe # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> Maybe a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [Maybe a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> Maybe a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [Maybe a] -> Encoding #
ToJSON1 Identity # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> Identity a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [Identity a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> Identity a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [Identity a] -> Encoding #
ToJSON1 Min # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> Min a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [Min a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> Min a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [Min a] -> Encoding #
ToJSON1 Max # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> Max a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [Max a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> Max a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [Max a] -> Encoding #
ToJSON1 First # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> First a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [First a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> First a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [First a] -> Encoding #
ToJSON1 Last # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> Last a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [Last a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> Last a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [Last a] -> Encoding #
ToJSON1 WrappedMonoid # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> WrappedMonoid a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [WrappedMonoid a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> WrappedMonoid a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [WrappedMonoid a] -> Encoding #
ToJSON1 Option # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> Option a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [Option a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> Option a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [Option a] -> Encoding #
ToJSON1 NonEmpty # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> NonEmpty a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [NonEmpty a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> NonEmpty a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [NonEmpty a] -> Encoding #
ToJSON1 Dual # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> Dual a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [Dual a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> Dual a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [Dual a] -> Encoding #
ToJSON1 First # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> First a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [First a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> First a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [First a] -> Encoding #
ToJSON1 Last # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> Last a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [Last a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> Last a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [Last a] -> Encoding #
ToJSON1 Tree # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> Tree a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [Tree a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> Tree a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [Tree a] -> Encoding #
ToJSON1 Seq # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> Seq a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [Seq a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> Seq a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [Seq a] -> Encoding #
ToJSON1 IntMap # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> IntMap a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [IntMap a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> IntMap a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [IntMap a] -> Encoding #
ToJSON1 Set # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> Set a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [Set a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> Set a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [Set a] -> Encoding #
ToJSON1 DList # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> DList a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [DList a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> DList a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [DList a] -> Encoding #
ToJSON1 HashSet # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> HashSet a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [HashSet a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> HashSet a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [HashSet a] -> Encoding #
ToJSON1 Vector # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> Vector a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [Vector a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> Vector a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [Vector a] -> Encoding #
ToJSON a => ToJSON1 (Either a) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> Either a a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [Either a a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> Either a a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [Either a a] -> Encoding #
ToJSON a => ToJSON1 ((,) a) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> (a, a) -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [(a, a)] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> (a, a) -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [(a, a)] -> Encoding #
ToJSON1 (Proxy *) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> Proxy * a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [Proxy * a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> Proxy * a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [Proxy * a] -> Encoding #
ToJSONKey k => ToJSON1 (Map k) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> Map k a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [Map k a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> Map k a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [Map k a] -> Encoding #
ToJSONKey k => ToJSON1 (HashMap k) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> HashMap k a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [HashMap k a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> HashMap k a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [HashMap k a] -> Encoding #
(ToJSON a, ToJSON b) => ToJSON1 ((,,) a b) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> (a, b, a) -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [(a, b, a)] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> (a, b, a) -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [(a, b, a)] -> Encoding #
ToJSON a => ToJSON1 (Const * a) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> Const * a a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [Const * a a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> Const * a a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [Const * a a] -> Encoding #
ToJSON1 (Tagged k a) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> Tagged k a a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [Tagged k a a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> Tagged k a a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [Tagged k a a] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c) => ToJSON1 ((,,,) a b c) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> (a, b, c, a) -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [(a, b, c, a)] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> (a, b, c, a) -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [(a, b, c, a)] -> Encoding #
(ToJSON1 f, ToJSON1 g) => ToJSON1 (Sum * f g) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> Sum * f g a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [Sum * f g a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> Sum * f g a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [Sum * f g a] -> Encoding #
(ToJSON1 f, ToJSON1 g) => ToJSON1 (Product * f g) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> Product * f g a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [Product * f g a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> Product * f g a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [Product * f g a] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d) => ToJSON1 ((,,,,) a b c d) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> (a, b, c, d, a) -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [(a, b, c, d, a)] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> (a, b, c, d, a) -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [(a, b, c, d, a)] -> Encoding #
(ToJSON1 f, ToJSON1 g) => ToJSON1 (Compose * * f g) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> Compose * * f g a -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [Compose * * f g a] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> Compose * * f g a -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [Compose * * f g a] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e) => ToJSON1 ((,,,,,) a b c d e) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> (a, b, c, d, e, a) -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [(a, b, c, d, e, a)] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> (a, b, c, d, e, a) -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [(a, b, c, d, e, a)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f) => ToJSON1 ((,,,,,,) a b c d e f) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> (a, b, c, d, e, f, a) -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [(a, b, c, d, e, f, a)] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> (a, b, c, d, e, f, a) -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [(a, b, c, d, e, f, a)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g) => ToJSON1 ((,,,,,,,) a b c d e f g) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> (a, b, c, d, e, f, g, a) -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [(a, b, c, d, e, f, g, a)] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> (a, b, c, d, e, f, g, a) -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [(a, b, c, d, e, f, g, a)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h) => ToJSON1 ((,,,,,,,,) a b c d e f g h) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> (a, b, c, d, e, f, g, h, a) -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [(a, b, c, d, e, f, g, h, a)] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> (a, b, c, d, e, f, g, h, a) -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [(a, b, c, d, e, f, g, h, a)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i) => ToJSON1 ((,,,,,,,,,) a b c d e f g h i) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> (a, b, c, d, e, f, g, h, i, a) -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [(a, b, c, d, e, f, g, h, i, a)] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> (a, b, c, d, e, f, g, h, i, a) -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [(a, b, c, d, e, f, g, h, i, a)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j) => ToJSON1 ((,,,,,,,,,,) a b c d e f g h i j) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> (a, b, c, d, e, f, g, h, i, j, a) -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [(a, b, c, d, e, f, g, h, i, j, a)] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> (a, b, c, d, e, f, g, h, i, j, a) -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [(a, b, c, d, e, f, g, h, i, j, a)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j, ToJSON k) => ToJSON1 ((,,,,,,,,,,,) a b c d e f g h i j k) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> (a, b, c, d, e, f, g, h, i, j, k, a) -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [(a, b, c, d, e, f, g, h, i, j, k, a)] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> (a, b, c, d, e, f, g, h, i, j, k, a) -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [(a, b, c, d, e, f, g, h, i, j, k, a)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j, ToJSON k, ToJSON l) => ToJSON1 ((,,,,,,,,,,,,) a b c d e f g h i j k l) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> (a, b, c, d, e, f, g, h, i, j, k, l, a) -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [(a, b, c, d, e, f, g, h, i, j, k, l, a)] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> (a, b, c, d, e, f, g, h, i, j, k, l, a) -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [(a, b, c, d, e, f, g, h, i, j, k, l, a)] -> Encoding #
(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) => ToJSON1 ((,,,,,,,,,,,,,) a b c d e f g h i j k l m) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, a) -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [(a, b, c, d, e, f, g, h, i, j, k, l, m, a)] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, a) -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [(a, b, c, d, e, f, g, h, i, j, k, l, m, a)] -> Encoding #
(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) => ToJSON1 ((,,,,,,,,,,,,,,) a b c d e f g h i j k l m n) # |
Methods liftToJSON :: (a -> Value) -> ([a] -> Value) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, a) -> Value # liftToJSONList :: (a -> Value) -> ([a] -> Value) -> [(a, b, c, d, e, f, g, h, i, j, k, l, m, n, a)] -> Value # liftToEncoding :: (a -> Encoding) -> ([a] -> Encoding) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, a) -> Encoding # liftToEncodingList :: (a -> Encoding) -> ([a] -> Encoding) -> [(a, b, c, d, e, f, g, h, i, j, k, l, m, n, a)] -> Encoding #

toJSON1 :: (ToJSON1 f, ToJSON a) => f a -> Value #

Lift the standard `toJSON` function through the type constructor.

toEncoding1 :: (ToJSON1 f, ToJSON a) => f a -> Encoding #

Lift the standard `toEncoding` function through the type constructor.

class ToJSON2 f where #

Lifting of the `ToJSON` class to binary type constructors.

Instead of manually writing your `ToJSON2` instance, Data.Aeson.TH provides Template Haskell functions which will derive an instance at compile time.

The compiler cannot provide a default generic implementation for `liftToJSON2`, unlike `toJSON` and `liftToJSON`.

Minimal complete definition

liftToJSON2, liftToEncoding2

Methods

liftToJSON2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> f a b -> Value #

liftToJSONList2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> [f a b] -> Value #

liftToEncoding2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> f a b -> Encoding #

liftToEncodingList2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> [f a b] -> Encoding #

Instances

ToJSON2 Either # |
Methods liftToJSON2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> Either a b -> Value # liftToJSONList2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> [Either a b] -> Value # liftToEncoding2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> Either a b -> Encoding # liftToEncodingList2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> [Either a b] -> Encoding #
ToJSON2 (,) # |
Methods liftToJSON2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> (a, b) -> Value # liftToJSONList2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> [(a, b)] -> Value # liftToEncoding2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> (a, b) -> Encoding # liftToEncodingList2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> [(a, b)] -> Encoding #
ToJSON a => ToJSON2 ((,,) a) # |
Methods liftToJSON2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> (a, a, b) -> Value # liftToJSONList2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> [(a, a, b)] -> Value # liftToEncoding2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> (a, a, b) -> Encoding # liftToEncodingList2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> [(a, a, b)] -> Encoding #
ToJSON2 (Const *) # |
Methods liftToJSON2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> Const * a b -> Value # liftToJSONList2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> [Const * a b] -> Value # liftToEncoding2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> Const * a b -> Encoding # liftToEncodingList2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> [Const * a b] -> Encoding #
ToJSON2 (Tagged *) # |
Methods liftToJSON2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> Tagged * a b -> Value # liftToJSONList2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> [Tagged * a b] -> Value # liftToEncoding2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> Tagged * a b -> Encoding # liftToEncodingList2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> [Tagged * a b] -> Encoding #
(ToJSON a, ToJSON b) => ToJSON2 ((,,,) a b) # |
Methods liftToJSON2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> (a, b, a, b) -> Value # liftToJSONList2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> [(a, b, a, b)] -> Value # liftToEncoding2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> (a, b, a, b) -> Encoding # liftToEncodingList2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> [(a, b, a, b)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c) => ToJSON2 ((,,,,) a b c) # |
Methods liftToJSON2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> (a, b, c, a, b) -> Value # liftToJSONList2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> [(a, b, c, a, b)] -> Value # liftToEncoding2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> (a, b, c, a, b) -> Encoding # liftToEncodingList2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> [(a, b, c, a, b)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d) => ToJSON2 ((,,,,,) a b c d) # |
Methods liftToJSON2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> (a, b, c, d, a, b) -> Value # liftToJSONList2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> [(a, b, c, d, a, b)] -> Value # liftToEncoding2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> (a, b, c, d, a, b) -> Encoding # liftToEncodingList2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> [(a, b, c, d, a, b)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e) => ToJSON2 ((,,,,,,) a b c d e) # |
Methods liftToJSON2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> (a, b, c, d, e, a, b) -> Value # liftToJSONList2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> [(a, b, c, d, e, a, b)] -> Value # liftToEncoding2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> (a, b, c, d, e, a, b) -> Encoding # liftToEncodingList2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> [(a, b, c, d, e, a, b)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f) => ToJSON2 ((,,,,,,,) a b c d e f) # |
Methods liftToJSON2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> (a, b, c, d, e, f, a, b) -> Value # liftToJSONList2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> [(a, b, c, d, e, f, a, b)] -> Value # liftToEncoding2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> (a, b, c, d, e, f, a, b) -> Encoding # liftToEncodingList2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> [(a, b, c, d, e, f, a, b)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g) => ToJSON2 ((,,,,,,,,) a b c d e f g) # |
Methods liftToJSON2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> (a, b, c, d, e, f, g, a, b) -> Value # liftToJSONList2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> [(a, b, c, d, e, f, g, a, b)] -> Value # liftToEncoding2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> (a, b, c, d, e, f, g, a, b) -> Encoding # liftToEncodingList2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> [(a, b, c, d, e, f, g, a, b)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h) => ToJSON2 ((,,,,,,,,,) a b c d e f g h) # |
Methods liftToJSON2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> (a, b, c, d, e, f, g, h, a, b) -> Value # liftToJSONList2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> [(a, b, c, d, e, f, g, h, a, b)] -> Value # liftToEncoding2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> (a, b, c, d, e, f, g, h, a, b) -> Encoding # liftToEncodingList2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> [(a, b, c, d, e, f, g, h, a, b)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i) => ToJSON2 ((,,,,,,,,,,) a b c d e f g h i) # |
Methods liftToJSON2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> (a, b, c, d, e, f, g, h, i, a, b) -> Value # liftToJSONList2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> [(a, b, c, d, e, f, g, h, i, a, b)] -> Value # liftToEncoding2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> (a, b, c, d, e, f, g, h, i, a, b) -> Encoding # liftToEncodingList2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> [(a, b, c, d, e, f, g, h, i, a, b)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j) => ToJSON2 ((,,,,,,,,,,,) a b c d e f g h i j) # |
Methods liftToJSON2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> (a, b, c, d, e, f, g, h, i, j, a, b) -> Value # liftToJSONList2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> [(a, b, c, d, e, f, g, h, i, j, a, b)] -> Value # liftToEncoding2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> (a, b, c, d, e, f, g, h, i, j, a, b) -> Encoding # liftToEncodingList2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> [(a, b, c, d, e, f, g, h, i, j, a, b)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j, ToJSON k) => ToJSON2 ((,,,,,,,,,,,,) a b c d e f g h i j k) # |
Methods liftToJSON2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> (a, b, c, d, e, f, g, h, i, j, k, a, b) -> Value # liftToJSONList2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> [(a, b, c, d, e, f, g, h, i, j, k, a, b)] -> Value # liftToEncoding2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> (a, b, c, d, e, f, g, h, i, j, k, a, b) -> Encoding # liftToEncodingList2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> [(a, b, c, d, e, f, g, h, i, j, k, a, b)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j, ToJSON k, ToJSON l) => ToJSON2 ((,,,,,,,,,,,,,) a b c d e f g h i j k l) # |
Methods liftToJSON2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> (a, b, c, d, e, f, g, h, i, j, k, l, a, b) -> Value # liftToJSONList2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> [(a, b, c, d, e, f, g, h, i, j, k, l, a, b)] -> Value # liftToEncoding2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> (a, b, c, d, e, f, g, h, i, j, k, l, a, b) -> Encoding # liftToEncodingList2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> [(a, b, c, d, e, f, g, h, i, j, k, l, a, b)] -> Encoding #
(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) => ToJSON2 ((,,,,,,,,,,,,,,) a b c d e f g h i j k l m) # |
Methods liftToJSON2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, a, b) -> Value # liftToJSONList2 :: (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> [(a, b, c, d, e, f, g, h, i, j, k, l, m, a, b)] -> Value # liftToEncoding2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, a, b) -> Encoding # liftToEncodingList2 :: (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> [(a, b, c, d, e, f, g, h, i, j, k, l, m, a, b)] -> Encoding #

toJSON2 :: (ToJSON2 f, ToJSON a, ToJSON b) => f a b -> Value #

Lift the standard `toJSON` function through the type constructor.

toEncoding2 :: (ToJSON2 f, ToJSON a, ToJSON b) => f a b -> Encoding #

Lift the standard `toEncoding` function through the type constructor.

## Generic JSON classes and options

class GFromJSON arity f where #

Class of generic representation types that can be converted from JSON.

Minimal complete definition

gParseJSON

Methods

gParseJSON :: Options -> FromArgs arity a -> Value -> Parser (f a) #

This method (applied to `defaultOptions`) is used as the default generic implementation of `parseJSON` (if the `arity` is `Zero`) or `liftParseJSON` (if the `arity` is `One`).

Instances

GFromJSON arity U1 # |
Methods gParseJSON :: Options -> FromArgs arity a -> Value -> Parser (U1 a) #
GFromJSON One Par1 # |
Methods gParseJSON :: Options -> FromArgs One a -> Value -> Parser (Par1 a) #
FromJSON1 f => GFromJSON One (Rec1 f) # |
Methods gParseJSON :: Options -> FromArgs One a -> Value -> Parser (Rec1 f a) #
(AllNullary ((:+:) a b) allNullary, ParseSum * arity ((:+:) a b) allNullary) => GFromJSON arity ((:+:) a b) # |
Methods gParseJSON :: Options -> FromArgs arity a -> Value -> Parser ((a :+: b) a) #
(FromProduct arity a, FromProduct arity b, ProductSize a, ProductSize b) => GFromJSON arity ((:*:) a b) # |
Methods gParseJSON :: Options -> FromArgs arity a -> Value -> Parser ((a :*: b) a) #
ConsFromJSON arity a => GFromJSON arity (C1 c a) # |
Methods gParseJSON :: Options -> FromArgs arity a -> Value -> Parser (C1 c a a) #
FromJSON a => GFromJSON arity (K1 i a) # |
Methods gParseJSON :: Options -> FromArgs arity a -> Value -> Parser (K1 i a a) #
(FromJSON1 f, GFromJSON One g) => GFromJSON One ((:.:) f g) # |
Methods gParseJSON :: Options -> FromArgs One a -> Value -> Parser ((f :.: g) a) #
GFromJSON arity a => GFromJSON arity (M1 i c a) # |
Methods gParseJSON :: Options -> FromArgs arity a -> Value -> Parser (M1 i c a a) #

data FromArgs arity a where #

A `FromArgs` value either stores nothing (for `FromJSON`) or it stores the two function arguments that decode occurrences of the type parameter (for `FromJSON1`).

Constructors

NoFromArgs :: FromArgs Zero a |
From1Args :: (Value -> Parser a) -> (Value -> Parser [a]) -> FromArgs One a |

class GToJSON arity f where #

Class of generic representation types that can be converted to JSON.

Minimal complete definition

gToJSON

Methods

gToJSON :: Options -> ToArgs Value arity a -> f a -> Value #

This method (applied to `defaultOptions`) is used as the default generic implementation of `toJSON` (if the `arity` is `Zero`) or `liftToJSON` (if the `arity` is `One`).

Instances

GToJSON arity U1 # |
Methods gToJSON :: Options -> ToArgs Value arity a -> U1 a -> Value #
GToJSON One Par1 # |
Methods gToJSON :: Options -> ToArgs Value One a -> Par1 a -> Value #
ToJSON1 f => GToJSON One (Rec1 f) # |
Methods gToJSON :: Options -> ToArgs Value One a -> Rec1 f a -> Value #
(AllNullary ((:+:) a b) allNullary, SumToJSON * arity ((:+:) a b) allNullary) => GToJSON arity ((:+:) a b) # |
Methods gToJSON :: Options -> ToArgs Value arity a -> (a :+: b) a -> Value #
(WriteProduct arity a, WriteProduct arity b, ProductSize a, ProductSize b) => GToJSON arity ((:*:) a b) # |
Methods gToJSON :: Options -> ToArgs Value arity a -> (a :*: b) a -> Value #
ConsToJSON arity a => GToJSON arity (C1 c a) # |
Methods gToJSON :: Options -> ToArgs Value arity a -> C1 c a a -> Value #
ToJSON a => GToJSON arity (K1 i a) # |
Methods gToJSON :: Options -> ToArgs Value arity a -> K1 i a a -> Value #
(ToJSON1 f, GToJSON One g) => GToJSON One ((:.:) f g) # |
Methods gToJSON :: Options -> ToArgs Value One a -> (f :.: g) a -> Value #
GToJSON arity a => GToJSON arity (M1 i c a) # |
Methods gToJSON :: Options -> ToArgs Value arity a -> M1 i c a a -> Value #

class GToEncoding arity f where #

Class of generic representation types that can be converted to a JSON `Encoding`.

Minimal complete definition

gToEncoding

Methods

gToEncoding :: Options -> ToArgs Encoding arity a -> f a -> Encoding #

This method (applied to `defaultOptions`) can be used as the default generic implementation of `toEncoding` (if the `arity` is `Zero`) or `liftToEncoding` (if the `arity` is `One`).

Instances

GToEncoding arity U1 # |
Methods gToEncoding :: Options -> ToArgs Encoding arity a -> U1 a -> Encoding #
GToEncoding One Par1 # |
Methods gToEncoding :: Options -> ToArgs Encoding One a -> Par1 a -> Encoding #
ToJSON1 f => GToEncoding One (Rec1 f) # |
Methods gToEncoding :: Options -> ToArgs Encoding One a -> Rec1 f a -> Encoding #
(AllNullary ((:+:) a b) allNullary, SumToEncoding * arity ((:+:) a b) allNullary) => GToEncoding arity ((:+:) a b) # |
Methods gToEncoding :: Options -> ToArgs Encoding arity a -> (a :+: b) a -> Encoding #
(EncodeProduct arity a, EncodeProduct arity b) => GToEncoding arity ((:*:) a b) # |
Methods gToEncoding :: Options -> ToArgs Encoding arity a -> (a :*: b) a -> Encoding #
ConsToEncoding arity a => GToEncoding arity (C1 c a) # |
Methods gToEncoding :: Options -> ToArgs Encoding arity a -> C1 c a a -> Encoding #
ToJSON a => GToEncoding arity (K1 i a) # |
Methods gToEncoding :: Options -> ToArgs Encoding arity a -> K1 i a a -> Encoding #
(ToJSON1 f, GToEncoding One g) => GToEncoding One ((:.:) f g) # |
Methods gToEncoding :: Options -> ToArgs Encoding One a -> (f :.: g) a -> Encoding #
GToEncoding arity a => GToEncoding arity (M1 i c a) # |
Methods gToEncoding :: Options -> ToArgs Encoding arity a -> M1 i c a a -> Encoding #

data ToArgs res arity a where #

A `ToArgs` value either stores nothing (for `ToJSON`) or it stores the two function arguments that encode occurrences of the type parameter (for `ToJSON1`).

Constructors

NoToArgs :: ToArgs res Zero a |
To1Args :: (a -> res) -> ([a] -> res) -> ToArgs res One a |

data Zero #

A type-level indicator that `ToJSON` or `FromJSON` is being derived generically.

data One #

A type-level indicator that `ToJSON1` or `FromJSON1` is being derived generically.

Instances

GToEncoding One Par1 # |
Methods gToEncoding :: Options -> ToArgs Encoding One a -> Par1 a -> Encoding #
GToJSON One Par1 # |
Methods gToJSON :: Options -> ToArgs Value One a -> Par1 a -> Value #
GFromJSON One Par1 # |
Methods gParseJSON :: Options -> FromArgs One a -> Value -> Parser (Par1 a) #
ToJSON1 f => GToEncoding One (Rec1 f) # |
Methods gToEncoding :: Options -> ToArgs Encoding One a -> Rec1 f a -> Encoding #
ToJSON1 f => GToJSON One (Rec1 f) # |
Methods gToJSON :: Options -> ToArgs Value One a -> Rec1 f a -> Value #
FromJSON1 f => GFromJSON One (Rec1 f) # |
Methods gParseJSON :: Options -> FromArgs One a -> Value -> Parser (Rec1 f a) #
(ToJSON1 f, GToEncoding One g) => GToEncoding One ((:.:) f g) # |
Methods gToEncoding :: Options -> ToArgs Encoding One a -> (f :.: g) a -> Encoding #
(ToJSON1 f, GToJSON One g) => GToJSON One ((:.:) f g) # |
Methods gToJSON :: Options -> ToArgs Value One a -> (f :.: g) a -> Value #
(FromJSON1 f, GFromJSON One g) => GFromJSON One ((:.:) f g) # |
Methods gParseJSON :: Options -> FromArgs One a -> Value -> Parser ((f :.: g) a) #

genericToJSON :: (Generic a, GToJSON Zero (Rep a)) => Options -> a -> Value #

A configurable generic JSON creator. This function applied to `defaultOptions` is used as the default for `toJSON` when the type is an instance of `Generic`.

genericLiftToJSON :: (Generic1 f, GToJSON One (Rep1 f)) => Options -> (a -> Value) -> ([a] -> Value) -> f a -> Value #

A configurable generic JSON creator. This function applied to `defaultOptions` is used as the default for `liftToJSON` when the type is an instance of `Generic1`.

genericToEncoding :: (Generic a, GToEncoding Zero (Rep a)) => Options -> a -> Encoding #

A configurable generic JSON encoder. This function applied to `defaultOptions` is used as the default for `toEncoding` when the type is an instance of `Generic`.

genericLiftToEncoding :: (Generic1 f, GToEncoding One (Rep1 f)) => Options -> (a -> Encoding) -> ([a] -> Encoding) -> f a -> Encoding #

A configurable generic JSON encoder. This function applied to `defaultOptions` is used as the default for `liftToEncoding` when the type is an instance of `Generic1`.

genericParseJSON :: (Generic a, GFromJSON Zero (Rep a)) => Options -> Value -> Parser a #

A configurable generic JSON decoder. This function applied to `defaultOptions` is used as the default for `parseJSON` when the type is an instance of `Generic`.

genericLiftParseJSON :: (Generic1 f, GFromJSON One (Rep1 f)) => Options -> (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (f a) #

A configurable generic JSON decoder. This function applied to `defaultOptions` is used as the default for `liftParseJSON` when the type is an instance of `Generic1`.

defaultOptions :: Options #

Default encoding `Options`:

    Options
    { fieldLabelModifier      = id
    , constructorTagModifier  = id
    , allNullaryToStringTag   = True
    , omitNothingFields       = False
    , sumEncoding             = defaultTaggedObject
    , unwrapUnaryRecords      = False
    }

# Inspecting ``Value`s`

withObject :: String -> (Object -> Parser a) -> Value -> Parser a #

``withObject` expected f value` applies `f` to the `Object` when `value` is an `Object` and fails using ``typeMismatch` expected` otherwise.

withText :: String -> (Text -> Parser a) -> Value -> Parser a #

``withText` expected f value` applies `f` to the `Text` when `value` is a `String` and fails using ``typeMismatch` expected` otherwise.

withArray :: String -> (Array -> Parser a) -> Value -> Parser a #

``withArray` expected f value` applies `f` to the `Array` when `value` is an `Array` and fails using ``typeMismatch` expected` otherwise.

withNumber :: String -> (Number -> Parser a) -> Value -> Parser a #

Deprecated: Use withScientific instead

``withNumber` expected f value` applies `f` to the `Number` when `value` is a `Number` and fails using ``typeMismatch` expected` otherwise.

withScientific :: String -> (Scientific -> Parser a) -> Value -> Parser a #

``withScientific` expected f value` applies `f` to the `Scientific` number when `value` is a `Number` and fails using ``typeMismatch` expected` otherwise.

withBool :: String -> (Bool -> Parser a) -> Value -> Parser a #

``withBool` expected f value` applies `f` to the `Bool` when `value` is a `Bool` and fails using ``typeMismatch` expected` otherwise.

# Constructors and accessors

data Series #

A series of values that, when encoded, should be separated by commas. Since 0.11.0.0, the `.=` operator is overloaded to create either `(Text, Value)` or `Series`. You can use Series when encoding directly to a bytestring builder as in the following example:

    toEncoding (Person name age) = pairs ("name" .= name <> "age" .= age)

Instances

Semigroup Series # |
Methods (<>) :: Series -> Series -> Series # sconcat :: NonEmpty Series -> Series # stimes :: Integral b => b -> Series -> Series #
Monoid Series # |
Methods mempty :: Series # mappend :: Series -> Series -> Series # mconcat :: [Series] -> Series #
KeyValue Series # |
Methods (.=) :: ToJSON v => Text -> v -> Series #

pairs :: Series -> Encoding #

Encode a series of key/value pairs, separated by commas.

foldable :: (Foldable t, ToJSON a) => t a -> Encoding #

Encode a `Foldable` as a JSON array.

(.:) :: FromJSON a => Object -> Text -> Parser a #

Retrieve the value associated with the given key of an `Object`. The result is `empty` if the key is not present or the value cannot be converted to the desired type.

This accessor is appropriate if the key and value must be present in an object for it to be valid. If the key and value are optional, use `.:?` instead.

(.:?) :: FromJSON a => Object -> Text -> Parser (Maybe a) #

Retrieve the value associated with the given key of an `Object`. The result is `Nothing` if the key is not present or if its value is `Null`, or `empty` if the value cannot be converted to the desired type.

This accessor is most useful if the key and value can be absent from an object without affecting its validity. If the key and value are mandatory, use `.:` instead.

(.:!) :: FromJSON a => Object -> Text -> Parser (Maybe a) #

Retrieve the value associated with the given key of an `Object`. The result is `Nothing` if the key is not present or `empty` if the value cannot be converted to the desired type.

This differs from `.:?` by attempting to parse `Null` the same as any other JSON value, instead of interpreting it as `Nothing`.

(.!=) :: Parser (Maybe a) -> a -> Parser a #

Helper for use in combination with `.:?` to provide default values for optional JSON object fields.

This combinator is most useful if the key and value can be absent from an object without affecting its validity and we know a default value to assign in that case. If the key and value are mandatory, use `.:` instead.

Example usage:

     v1 <- o .:? "opt_field_with_dfl" .!= "default_val"
     v2 <- o .:  "mandatory_field"
     v3 <- o .:? "opt_field2"

object :: [Pair] -> Value #

Create a `Value` from a list of name/value `Pair`s. If duplicate keys arise, earlier keys and their associated values win.

# Parsing

json :: Parser Value #

Parse a top-level JSON value.

The conversion of a parsed value to a Haskell value is deferred until the Haskell value is needed. This may improve performance if only a subset of the results of conversions are needed, but at a cost in thunk allocation.

This function is an alias for `value`. In aeson 0.8 and earlier, it parsed only object or array types, in conformance with the now-obsolete RFC 4627.

json' :: Parser Value #

Parse a top-level JSON value.

This is a strict version of `json` which avoids building up thunks during parsing; it performs all conversions immediately. Prefer this version if most of the JSON data needs to be accessed.

This function is an alias for `value'`. In aeson 0.8 and earlier, it parsed only object or array types, in conformance with the now-obsolete RFC 4627.