Safe Haskell	None
Language	Haskell2010

Data.Aeson.Micro

Contents

Core JSON types
- Constructors
- Accessors
Encoding and decoding
Prism-style parsers
Type conversion

Description

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

Synopsis

data Value
- = Object !Object
- | Array [Value]
- | String !Text
- | Number !Double
- | Bool !Bool
- | Null
type Object = Map Text Value
type Pair = (Text, Value)
(.=) :: ToJSON v => Text -> v -> Pair
object :: [Pair] -> Value
emptyArray :: Value
emptyObject :: Value
(.:) :: 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
encode :: ToJSON a => a -> ByteString
encodeStrict :: ToJSON a => a -> ByteString
encodeToBuilder :: ToJSON a => a -> Builder
decodeStrict :: FromJSON a => ByteString -> Maybe a
decode :: FromJSON a => ByteString -> Maybe a
decodeStrictN :: FromJSON a => ByteString -> Maybe [a]
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
class FromJSON a where
- parseJSON :: Value -> Parser a
data Parser a
parseMaybe :: (a -> Parser b) -> a -> Maybe b
class ToJSON a where
- toJSON :: a -> Value

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

Instances details

Data Value #

Instance details

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 #

IsString Value #

Instance details

Defined in Data.Aeson.Micro

Methods

fromString :: String -> Value #

Generic Value #

Instance details

Defined in Data.Aeson.Micro

Associated Types

type Rep Value

Instance details

Defined in Data.Aeson.Micro

type Rep Value = D1 ('MetaData "Value" "Data.Aeson.Micro" "microaeson-0.1.0.1-EzJWrVCb4s2KhRq3xj8Bhi" '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))))

Methods

from :: Value -> Rep Value x #

to :: Rep Value x -> Value #

Read Value #

Instance details

Defined in Data.Aeson.Micro

Methods

readsPrec :: Int -> ReadS Value #

readList :: ReadS [Value] #

readPrec :: ReadPrec Value #

readListPrec :: ReadPrec [Value] #

Show Value #

Instance details

Defined in Data.Aeson.Micro

Methods

showsPrec :: Int -> Value -> ShowS #

show :: Value -> String #

showList :: [Value] -> ShowS #

NFData Value #

Instance details

Defined in Data.Aeson.Micro

Methods

rnf :: Value -> () #

Eq Value #

Instance details

Defined in Data.Aeson.Micro

Methods

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

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

FromJSON Value #

Instance details

Defined in Data.Aeson.Micro

Methods

parseJSON :: Value -> Parser Value #

ToJSON Value #

Instance details

Defined in Data.Aeson.Micro

Methods

toJSON :: Value -> Value #

type Rep Value #

Instance details

Defined in Data.Aeson.Micro

type Rep Value = D1 ('MetaData "Value" "Data.Aeson.Micro" "microaeson-0.1.0.1-EzJWrVCb4s2KhRq3xj8Bhi" '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

Instances details

FromJSON Int16 #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser Int16 #
FromJSON Int32 #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser Int32 #
FromJSON Int64 #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser Int64 #
FromJSON Int8 #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser Int8 #
FromJSON Word16 #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser Word16 #
FromJSON Word32 #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser Word32 #
FromJSON Word64 #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser Word64 #
FromJSON Word8 #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser Word8 #
FromJSON Ordering #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser Ordering #
FromJSON Value #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser Value #
FromJSON Text #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser Text #
FromJSON Text #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser Text #
FromJSON Integer #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser Integer #
FromJSON () #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser () #
FromJSON Bool #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser Bool #
FromJSON Double #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser Double #
FromJSON Float #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser Float #
FromJSON Int #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser Int #
FromJSON Word #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser Word #
FromJSON a => FromJSON (Maybe a) #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser (Maybe a) #
FromJSON a => FromJSON [a] #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser [a] #
FromJSON v => FromJSON (Map Text v) #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser (Map Text v) #
(FromJSON a, FromJSON b) => FromJSON (a, b) #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser (a, b) #
(FromJSON a, FromJSON b, FromJSON c) => FromJSON (a, b, c) #
Instance details 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) #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser (a, b, c, d) #

data Parser a #

JSON Parser Monad used by FromJSON

Instances

Instances details

MonadFail Parser #
Instance details Defined in Data.Aeson.Micro Methods fail :: String -> Parser a #
Applicative Parser #
Instance details 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 #
Functor Parser #
Instance details Defined in Data.Aeson.Micro Methods fmap :: (a -> b) -> Parser a -> Parser b # (<$) :: a -> Parser b -> Parser a #
Monad Parser #
Instance details Defined in Data.Aeson.Micro Methods (>>=) :: Parser a -> (a -> Parser b) -> Parser b # (>>) :: Parser a -> Parser b -> Parser b # return :: a -> 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

Instances details

ToJSON Int16 #
Instance details Defined in Data.Aeson.Micro Methods toJSON :: Int16 -> Value #
ToJSON Int32 #
Instance details Defined in Data.Aeson.Micro Methods toJSON :: Int32 -> Value #
ToJSON Int64 #	Possibly lossy due to conversion to `Double`
Instance details Defined in Data.Aeson.Micro Methods toJSON :: Int64 -> Value #
ToJSON Int8 #
Instance details Defined in Data.Aeson.Micro Methods toJSON :: Int8 -> Value #
ToJSON Word16 #
Instance details Defined in Data.Aeson.Micro Methods toJSON :: Word16 -> Value #
ToJSON Word32 #
Instance details Defined in Data.Aeson.Micro Methods toJSON :: Word32 -> Value #
ToJSON Word64 #	Possibly lossy due to conversion to `Double`
Instance details Defined in Data.Aeson.Micro Methods toJSON :: Word64 -> Value #
ToJSON Word8 #
Instance details Defined in Data.Aeson.Micro Methods toJSON :: Word8 -> Value #
ToJSON Value #
Instance details Defined in Data.Aeson.Micro Methods toJSON :: Value -> Value #
ToJSON Text #
Instance details Defined in Data.Aeson.Micro Methods toJSON :: Text -> Value #
ToJSON Text #
Instance details Defined in Data.Aeson.Micro Methods toJSON :: Text -> Value #
ToJSON Integer #	Possibly lossy due to conversion to `Double`
Instance details Defined in Data.Aeson.Micro Methods toJSON :: Integer -> Value #
ToJSON () #
Instance details Defined in Data.Aeson.Micro Methods toJSON :: () -> Value #
ToJSON Bool #
Instance details Defined in Data.Aeson.Micro Methods toJSON :: Bool -> Value #
ToJSON Double #
Instance details Defined in Data.Aeson.Micro Methods toJSON :: Double -> Value #
ToJSON Float #
Instance details Defined in Data.Aeson.Micro Methods toJSON :: Float -> Value #
ToJSON Int #
Instance details Defined in Data.Aeson.Micro Methods toJSON :: Int -> Value #
ToJSON Word #
Instance details Defined in Data.Aeson.Micro Methods toJSON :: Word -> Value #
ToJSON a => ToJSON (Maybe a) #
Instance details Defined in Data.Aeson.Micro Methods toJSON :: Maybe a -> Value #
ToJSON a => ToJSON [a] #
Instance details Defined in Data.Aeson.Micro Methods toJSON :: [a] -> Value #
ToJSON v => ToJSON (Map Text v) #
Instance details Defined in Data.Aeson.Micro Methods toJSON :: Map Text v -> Value #
(ToJSON a, ToJSON b) => ToJSON (a, b) #
Instance details Defined in Data.Aeson.Micro Methods toJSON :: (a, b) -> Value #
(ToJSON a, ToJSON b, ToJSON c) => ToJSON (a, b, c) #
Instance details Defined in Data.Aeson.Micro Methods toJSON :: (a, b, c) -> Value #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d) => ToJSON (a, b, c, d) #
Instance details Defined in Data.Aeson.Micro Methods toJSON :: (a, b, c, d) -> Value #

Limitations and divergences from aeson's API

Core JSON types

Instances

Constructors

Accessors

Encoding and decoding

Prism-style parsers

Type conversion

Instances

Instances

Instances

Limitations and divergences from `aeson`'s API