Prolude.Json

Aeson re-exports

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

withText name f value applies f to the Text when value is a String and fails otherwise.

Error message example

withText "MyType" f Null
-- Error: "parsing MyType failed, expected String, but encountered Null"

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

withObject name f value applies f to the Object when value is an Object and fails otherwise.

Error message example

withObject "MyType" f (String "oops")
-- Error: "parsing MyType failed, expected Object, but encountered String"

Aeson.Types re-exports

data Parser a

A JSON parser. N.B. This might not fit your usual understanding of "parser". Instead you might like to think of Parser as a "parse result", i.e. a parser to which the input has already been applied.

Instances

MonadFail Parser

Defined in Data.Aeson.Types.Internal

Methods

fail :: String -> Parser a

MonadFix Parser

Since: aeson-2.1.0.0

Defined in Data.Aeson.Types.Internal

Methods

mfix :: (a -> Parser a) -> Parser a

Alternative Parser

Defined in Data.Aeson.Types.Internal

Methods

empty :: Parser a

(<|>) :: Parser a -> Parser a -> Parser a

some :: Parser a -> Parser [a]

many :: Parser a -> Parser [a]

Applicative Parser

Defined in Data.Aeson.Types.Internal

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

Defined in Data.Aeson.Types.Internal

Methods

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

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

Monad Parser

Defined in Data.Aeson.Types.Internal

Methods

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

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

return :: a -> Parser a

MonadPlus Parser

Defined in Data.Aeson.Types.Internal

Methods

mzero :: Parser a

mplus :: Parser a -> Parser a -> Parser a

Monoid (Parser a)

Defined in Data.Aeson.Types.Internal

Methods

mempty :: Parser a

mappend :: Parser a -> Parser a -> Parser a

mconcat :: [Parser a] -> Parser a

Semigroup (Parser a)

Defined in Data.Aeson.Types.Internal

Methods

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

sconcat :: NonEmpty (Parser a) -> Parser a

stimes :: Integral b => b -> Parser a -> Parser a

Aeson functions

jsonEitherDecode :: FromJSON a => ByteString -> Either String a

Function alias for Aeson.eitherDecode

jsonEncode :: ToJSON a => a -> ByteString

Function alias for Aeson.encode