Copyright	(c) 2015-2016 Bryan O'Sullivan
License	BSD3
Maintainer	Bryan O'Sullivan <bos@serpentine.com>
Stability	experimental
Portability	portable
Safe Haskell	None
Language	Haskell2010

Data.Aeson.Internal

Description

Internal types and functions.

Note : all declarations in this module are unstable, and prone to being changed at any time.

Synopsis

data IResult a
- = IError JSONPath String
- | ISuccess a
data JSONPathElement
- = Key Key
- | Index ! Int
type JSONPath = [ JSONPathElement ]
(<?>) :: Parser a -> JSONPathElement -> Parser a
formatError :: JSONPath -> String -> String
ifromJSON :: FromJSON a => Value -> IResult a
iparse :: (a -> Parser b) -> a -> IResult b

Documentation

data IResult a Source #

The internal result of running a Parser .

Constructors

IError JSONPath String
ISuccess a

Instances

Instances details

Monad IResult Source #
Instance details Defined in Data.Aeson.Types.Internal Methods (>>=) :: IResult a -> (a -> IResult b) -> IResult b Source # (>>) :: IResult a -> IResult b -> IResult b Source # return :: a -> IResult a Source #
Functor IResult Source #
Instance details Defined in Data.Aeson.Types.Internal Methods fmap :: (a -> b) -> IResult a -> IResult b Source # (<$) :: a -> IResult b -> IResult a Source #
MonadFail IResult Source #
Instance details Defined in Data.Aeson.Types.Internal Methods fail :: String -> IResult a Source #
Applicative IResult Source #
Instance details Defined in Data.Aeson.Types.Internal Methods pure :: a -> IResult a Source # (<>) :: IResult (a -> b) -> IResult a -> IResult b Source # liftA2 :: (a -> b -> c) -> IResult a -> IResult b -> IResult c Source # (>) :: IResult a -> IResult b -> IResult b Source # (<*) :: IResult a -> IResult b -> IResult a Source #
Foldable IResult Source #
Instance details Defined in Data.Aeson.Types.Internal Methods fold :: Monoid m => IResult m -> m Source # foldMap :: Monoid m => (a -> m) -> IResult a -> m Source # foldMap' :: Monoid m => (a -> m) -> IResult a -> m Source # foldr :: (a -> b -> b) -> b -> IResult a -> b Source # foldr' :: (a -> b -> b) -> b -> IResult a -> b Source # foldl :: (b -> a -> b) -> b -> IResult a -> b Source # foldl' :: (b -> a -> b) -> b -> IResult a -> b Source # foldr1 :: (a -> a -> a) -> IResult a -> a Source # foldl1 :: (a -> a -> a) -> IResult a -> a Source # toList :: IResult a -> [a] Source # null :: IResult a -> Bool Source # length :: IResult a -> Int Source # elem :: Eq a => a -> IResult a -> Bool Source # maximum :: Ord a => IResult a -> a Source # minimum :: Ord a => IResult a -> a Source # sum :: Num a => IResult a -> a Source # product :: Num a => IResult a -> a Source #
Traversable IResult Source #
Instance details Defined in Data.Aeson.Types.Internal Methods traverse :: Applicative f => (a -> f b) -> IResult a -> f ( IResult b) Source # sequenceA :: Applicative f => IResult (f a) -> f ( IResult a) Source # mapM :: Monad m => (a -> m b) -> IResult a -> m ( IResult b) Source # sequence :: Monad m => IResult (m a) -> m ( IResult a) Source #
Alternative IResult Source #
Instance details Defined in Data.Aeson.Types.Internal Methods empty :: IResult a Source # (<\|>) :: IResult a -> IResult a -> IResult a Source # some :: IResult a -> IResult [a] Source # many :: IResult a -> IResult [a] Source #
MonadPlus IResult Source #
Instance details Defined in Data.Aeson.Types.Internal Methods mzero :: IResult a Source # mplus :: IResult a -> IResult a -> IResult a Source #
Eq a => Eq ( IResult a) Source #
Instance details Defined in Data.Aeson.Types.Internal Methods (==) :: IResult a -> IResult a -> Bool Source # (/=) :: IResult a -> IResult a -> Bool Source #
Show a => Show ( IResult a) Source #
Instance details Defined in Data.Aeson.Types.Internal Methods showsPrec :: Int -> IResult a -> ShowS Source # show :: IResult a -> String Source # showList :: [ IResult a] -> ShowS Source #
Semigroup ( IResult a) Source #
Instance details Defined in Data.Aeson.Types.Internal Methods (<>) :: IResult a -> IResult a -> IResult a Source # sconcat :: NonEmpty ( IResult a) -> IResult a Source # stimes :: Integral b => b -> IResult a -> IResult a Source #
Monoid ( IResult a) Source #
Instance details Defined in Data.Aeson.Types.Internal Methods mempty :: IResult a Source # mappend :: IResult a -> IResult a -> IResult a Source # mconcat :: [ IResult a] -> IResult a Source #
NFData a => NFData ( IResult a) Source #
Instance details Defined in Data.Aeson.Types.Internal Methods rnf :: IResult a -> () Source #

data JSONPathElement Source #

Elements of a JSON path used to describe the location of an error.

Constructors

Key Key	JSON path element of a key into an object, "object.key".
Index ! Int	JSON path element of an index into an array, "array[index]".

Instances

Instances details

Eq JSONPathElement Source #
Instance details Defined in Data.Aeson.Types.Internal Methods (==) :: JSONPathElement -> JSONPathElement -> Bool Source # (/=) :: JSONPathElement -> JSONPathElement -> Bool Source #
Ord JSONPathElement Source #
Instance details Defined in Data.Aeson.Types.Internal Methods compare :: JSONPathElement -> JSONPathElement -> Ordering Source # (<) :: JSONPathElement -> JSONPathElement -> Bool Source # (<=) :: JSONPathElement -> JSONPathElement -> Bool Source # (>) :: JSONPathElement -> JSONPathElement -> Bool Source # (>=) :: JSONPathElement -> JSONPathElement -> Bool Source # max :: JSONPathElement -> JSONPathElement -> JSONPathElement Source # min :: JSONPathElement -> JSONPathElement -> JSONPathElement Source #
Show JSONPathElement Source #
Instance details Defined in Data.Aeson.Types.Internal Methods showsPrec :: Int -> JSONPathElement -> ShowS Source # show :: JSONPathElement -> String Source # showList :: [ JSONPathElement ] -> ShowS Source #
NFData JSONPathElement Source #
Instance details Defined in Data.Aeson.Types.Internal Methods rnf :: JSONPathElement -> () Source #

type JSONPath = [ JSONPathElement ] Source #

(<?>) :: Parser a -> JSONPathElement -> Parser a Source #

Add JSON Path context to a parser

When parsing a complex structure, it helps to annotate (sub)parsers with context, so that if an error occurs, you can find its location.

withObject "Person" $ \o ->
  Person
    <$> o .: "name" <?> Key "name"
    <*> o .: "age"  <?> Key "age"

(Standard methods like (.:) already do this.)

With such annotations, if an error occurs, you will get a JSON Path location of that error.

Since 0.10

formatError :: JSONPath -> String -> String Source #

Annotate an error message with a JSONPath error location.

ifromJSON :: FromJSON a => Value -> IResult a Source #

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

iparse :: (a -> Parser b) -> a -> IResult b Source #

Run a Parser .