Data.Aeson.Micro

Minimal JavaScript Object Notation (JSON) support as per RFC 8259.

This API provides a subset (with a couple of divergences; see below) of aeson API but puts the emphasis on simplicity rather than performance and features.

The ToJSON and FromJSON instances are intended to have an encoding compatible with aeson's encoding.

Limitations and divergences from aeson's API

In order to reduce the dependency footprint and keep the code simpler, the following divergences from the aeson API have to be made:

• There are no FromJSON/ToJSON instances for Char & String.
• The type synonym (& the constructor of the same name) Object uses containers's Map rather than a HashMap unordered-containers.
• Array is represented by an ordinary list rather than a Vector from the vector package.
• Number uses Double instead of Scientific

Core JSON types

data Value

A JSON value represented as a Haskell value.

Constructors

Object !Object

Array [Value]

String !Text

Number !Double

Bool !Bool

Null

Instances

Eq Value

Defined in Data.Aeson.Micro

Methods

(==) :: Value -> Value -> Bool

(/=) :: Value -> Value -> Bool

Data Value

Defined in Data.Aeson.Micro

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 :: forall r r'. (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

Defined in Data.Aeson.Micro

Methods

readsPrec :: Int -> ReadS Value

readList :: ReadS [Value]

readPrec :: ReadPrec Value

readListPrec :: ReadPrec [Value]

Show Value

Defined in Data.Aeson.Micro

Methods

showsPrec :: Int -> Value -> ShowS

show :: Value -> String

showList :: [Value] -> ShowS

IsString Value

Defined in Data.Aeson.Micro

Methods

fromString :: String -> Value

Generic Value

Defined in Data.Aeson.Micro

Associated Types

type Rep Value :: Type -> Type

Methods

from :: Value -> Rep Value x

to :: Rep Value x -> Value

NFData Value

Defined in Data.Aeson.Micro

Methods

rnf :: Value -> ()

FromJSON Value

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser Value

ToJSON Value

Defined in Data.Aeson.Micro

Methods

toJSON :: Value -> Value

type Rep Value

Defined in Data.Aeson.Micro

type Rep Value = D1 ('MetaData "Value" "Data.Aeson.Micro" "microaeson-0.1.0.1-6v69xl011e3GZfSSG94uTZ" 'False) ((C1 ('MetaCons "Object" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 Object)) :+: (C1 ('MetaCons "Array" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 [Value])) :+: C1 ('MetaCons "String" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 Text)))) :+: (C1 ('MetaCons "Number" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 Double)) :+: (C1 ('MetaCons "Bool" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 Bool)) :+: C1 ('MetaCons "Null" 'PrefixI 'False) (U1 :: Type -> Type))))

type Object = Map Text Value

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

type Pair = (Text, Value)

A key/value pair for an Object

Constructors

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

A key-value pair for encoding a JSON object.

object :: [Pair] -> Value

Create a Value from a list of name/value Pairs.

emptyArray :: Value

The empty JSON Array (i.e. []).

emptyObject :: Value

The empty JSON Object (i.e. {}).

Accessors

(.:) :: 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

Encoding and decoding

encode :: ToJSON a => a -> ByteString

Serialise value as JSON/UTF-8-encoded lazy ByteString

encodeStrict :: ToJSON a => a -> ByteString

Serialise value as JSON/UTF-8-encoded strict ByteString

encodeToBuilder :: ToJSON a => a -> Builder

Serialise value as JSON/UTF8-encoded Builder

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

Decode a single JSON document

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

Decode a single JSON document

decodeStrictN :: FromJSON a => ByteString -> Maybe [a]

Decode multiple concatenated JSON documents

Prism-style parsers

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

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

withArray :: String -> ([Value] -> Parser a) -> Value -> Parser a

withNumber :: String -> (Double -> Parser a) -> Value -> Parser a

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

Type conversion

class FromJSON a where

A type that JSON can be deserialised into

Methods

parseJSON :: Value -> Parser a

Decode a JSON value into a native Haskell type

Instances

FromJSON Bool

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser Bool

FromJSON Double

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser Double

FromJSON Float

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser Float

FromJSON Int

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser Int

FromJSON Int8

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser Int8

FromJSON Int16

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser Int16

FromJSON Int32

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser Int32

FromJSON Int64

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser Int64

FromJSON Integer

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser Integer

FromJSON Ordering

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser Ordering

FromJSON Word

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser Word

FromJSON Word8

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser Word8

FromJSON Word16

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser Word16

FromJSON Word32

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser Word32

FromJSON Word64

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser Word64

FromJSON ()

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser ()

FromJSON Text

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser Text

FromJSON Text

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser Text

FromJSON Value

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser Value

FromJSON a => FromJSON [a]

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser [a]

FromJSON a => FromJSON (Maybe a)

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser (Maybe a)

(FromJSON a, FromJSON b) => FromJSON (a, b)

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser (a, b)

FromJSON v => FromJSON (Map Text v)

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser (Map Text v)

(FromJSON a, FromJSON b, FromJSON c) => FromJSON (a, b, c)

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser (a, b, c)

(FromJSON a, FromJSON b, FromJSON c, FromJSON d) => FromJSON (a, b, c, d)

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser (a, b, c, d)

data Parser a

JSON Parser Monad used by FromJSON

Instances

Monad Parser

Defined in Data.Aeson.Micro

Methods

(>>=) :: Parser a -> (a -> Parser b) -> Parser b

(>>) :: Parser a -> Parser b -> Parser b

return :: a -> Parser a

Functor Parser

Defined in Data.Aeson.Micro

Methods

fmap :: (a -> b) -> Parser a -> Parser b

(<$) :: a -> Parser b -> Parser a

MonadFail Parser

Defined in Data.Aeson.Micro

Methods

fail :: String -> Parser a

Applicative Parser

Defined in Data.Aeson.Micro

Methods

pure :: a -> Parser a

(<*>) :: Parser (a -> b) -> Parser a -> Parser b

liftA2 :: (a -> b -> c) -> Parser a -> Parser b -> Parser c

(*>) :: Parser a -> Parser b -> Parser b

(<*) :: Parser a -> Parser b -> Parser a

parseMaybe :: (a -> Parser b) -> a -> Maybe b

Run Parser.

A common use-case is parseMaybe parseJSON.

class ToJSON a where

A type that can be converted to JSON.

Methods

toJSON :: a -> Value

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

Instances

ToJSON Bool

Defined in Data.Aeson.Micro

Methods

toJSON :: Bool -> Value

ToJSON Double

Defined in Data.Aeson.Micro

Methods

toJSON :: Double -> Value

ToJSON Float

Defined in Data.Aeson.Micro

Methods

toJSON :: Float -> Value

ToJSON Int

Defined in Data.Aeson.Micro

Methods

toJSON :: Int -> Value

ToJSON Int8

Defined in Data.Aeson.Micro

Methods

toJSON :: Int8 -> Value

ToJSON Int16

Defined in Data.Aeson.Micro

Methods

toJSON :: Int16 -> Value

ToJSON Int32

Defined in Data.Aeson.Micro

Methods

toJSON :: Int32 -> Value

ToJSON Int64

Possibly lossy due to conversion to Double

Defined in Data.Aeson.Micro

Methods

toJSON :: Int64 -> Value

ToJSON Integer

Possibly lossy due to conversion to Double

Defined in Data.Aeson.Micro

Methods

toJSON :: Integer -> Value

ToJSON Word

Defined in Data.Aeson.Micro

Methods

toJSON :: Word -> Value

ToJSON Word8

Defined in Data.Aeson.Micro

Methods

toJSON :: Word8 -> Value

ToJSON Word16

Defined in Data.Aeson.Micro

Methods

toJSON :: Word16 -> Value

ToJSON Word32

Defined in Data.Aeson.Micro

Methods

toJSON :: Word32 -> Value

ToJSON Word64

Possibly lossy due to conversion to Double

Defined in Data.Aeson.Micro

Methods

toJSON :: Word64 -> Value

ToJSON ()

Defined in Data.Aeson.Micro

Methods

toJSON :: () -> Value

ToJSON Text

Defined in Data.Aeson.Micro

Methods

toJSON :: Text -> Value

ToJSON Text

Defined in Data.Aeson.Micro

Methods

toJSON :: Text -> Value

ToJSON Value

Defined in Data.Aeson.Micro

Methods

toJSON :: Value -> Value

ToJSON a => ToJSON [a]

Defined in Data.Aeson.Micro

Methods

toJSON :: [a] -> Value

ToJSON a => ToJSON (Maybe a)

Defined in Data.Aeson.Micro

Methods

toJSON :: Maybe a -> Value

(ToJSON a, ToJSON b) => ToJSON (a, b)

Defined in Data.Aeson.Micro

Methods

toJSON :: (a, b) -> Value

ToJSON v => ToJSON (Map Text v)

Defined in Data.Aeson.Micro

Methods

toJSON :: Map Text v -> Value

(ToJSON a, ToJSON b, ToJSON c) => ToJSON (a, b, c)

Defined in Data.Aeson.Micro

Methods

toJSON :: (a, b, c) -> Value

(ToJSON a, ToJSON b, ToJSON c, ToJSON d) => ToJSON (a, b, c, d)

Defined in Data.Aeson.Micro

Methods

toJSON :: (a, b, c, d) -> Value