Safe Haskell	Safe-Inferred
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 & Value.
The type synonym (& the constructor of the same name) Value 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 Source #

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 Source #
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 Source #
Instance details Defined in Data.Aeson.Micro Methods fromString :: String -> Value #
Generic Value Source #
Instance details Defined in Data.Aeson.Micro Associated Types type Rep Value :: Type -> Type # Methods from :: Value -> Rep Value x # to :: Rep Value x -> Value #
Read Value Source #
Instance details Defined in Data.Aeson.Micro Methods readsPrec :: Int -> ReadS Value # readList :: ReadS [Value] # readPrec :: ReadPrec Value # readListPrec :: ReadPrec [Value] #
Show Value Source #
Instance details Defined in Data.Aeson.Micro Methods showsPrec :: Int -> Value -> ShowS # show :: Value -> String # showList :: [Value] -> ShowS #
NFData Value Source #
Instance details Defined in Data.Aeson.Micro Methods rnf :: Value -> () #
Eq Value Source #
Instance details Defined in Data.Aeson.Micro Methods (==) :: Value -> Value -> Bool # (/=) :: Value -> Value -> Bool #
FromJSON Value Source #
Instance details Defined in Data.Aeson.Micro Methods parseJSON :: Value -> Parser Value Source #
ToJSON Value Source #
Instance details Defined in Data.Aeson.Micro Methods toJSON :: Value -> Value Source #
type Rep Value Source #
Instance details Defined in Data.Aeson.Micro type Rep Value = D1 ('MetaData "Value" "Data.Aeson.Micro" "microaeson-0.1.0.1-inplace" '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 Source #

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

type Pair = (Text, Value) Source #

A key/value pair for an Value

Constructors

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

A key-value pair for encoding a JSON object.

object :: [Pair] -> Value Source #

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

emptyArray :: Value Source #

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

emptyObject :: Value Source #

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

Accessors

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

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

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

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

Encoding and decoding

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

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

encodeStrict :: ToJSON a => a -> ByteString Source #

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

encodeToBuilder :: ToJSON a => a -> Builder Source #

Serialise value as JSON/UTF8-encoded Builder

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

Decode a single JSON document

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

Decode a single JSON document

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

Decode multiple concatenated JSON documents

Prism-style parsers

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

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

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

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

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

Type conversion

class FromJSON a where Source #

A type that JSON can be deserialised into

Methods

parseJSON :: Value -> Parser a Source #

Decode a JSON value into a native Haskell type

Instances

Instances details

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

data Parser a Source #

JSON Parser Monad used by FromJSON

Instances

Instances details

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

Run Parser.

A common use-case is parseMaybe parseJSON.

class ToJSON a where Source #

A type that can be converted to JSON.

Methods

toJSON :: a -> Value Source #

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

Instances

Instances details

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

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