-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/

-- | Fast JSON parsing and encoding
--   
--   A JSON parsing and encoding library optimized for ease of use and high
--   performance.
--   
--   To get started, see the documentation for the Data.Aeson
--   module below.
--   
--   Parsing performance on a late 2013 MacBook Pro (2.6GHz Core i7),
--   running 64-bit GHC 7.10.1, for mostly-English tweets from Twitter's
--   JSON search API:
--   
--   
--   
- 6.4 KB payloads, English: 7570 msg/sec (47.6 MB/sec)
--   
- 14.6 KB payloads, Japanese: 3261 msg/sec (46.6 MB/sec)
--   
--   
--   Encoding performance on the same machine and data:
--   
--   
--   
- 6.4 KB payloads, English: 22738 msg/sec (142.9 MB/sec)
--   
- 14.6 KB payloads, Japanese: 15911 msg/sec (227.4 MB/sec)
--   
--   
--   (A note on naming: in Greek mythology, Aeson was the father of Jason.)
@package aeson
@version 1.1.2.0

-- | Efficiently and correctly parse a JSON string. The string must be
--   encoded as UTF-8.
--   
--   It can be useful to think of parsing as occurring in two phases:
--   
--   
--   
- Identification of the textual boundaries of a JSON value. This is
--   always strict, so that an invalid JSON document can be rejected as
--   soon as possible.
--   
- Conversion of a JSON value to a Haskell value. This may be either
--   immediate (strict) or deferred (lazy); see below for details.
--   
--   
--   The question of whether to choose a lazy or strict parser is subtle,
--   but it can have significant performance implications, resulting in
--   changes in CPU use and memory footprint of 30% to 50%, or occasionally
--   more. Measure the performance of your application with each!
module Data.Aeson.Parser

-- | Parse a top-level JSON value.
--   
--   The conversion of a parsed value to a Haskell value is deferred until
--   the Haskell value is needed. This may improve performance if only a
--   subset of the results of conversions are needed, but at a cost in
--   thunk allocation.
--   
--   This function is an alias for value. In aeson 0.8 and earlier,
--   it parsed only object or array types, in conformance with the
--   now-obsolete RFC 4627.
json :: Parser Value

-- | Parse any JSON value. You should usually json in preference to
--   this function, as this function relaxes the object-or-array
--   requirement of RFC 4627.
--   
--   In particular, be careful in using this function if you think your
--   code might interoperate with Javascript. A naïve Javascript library
--   that parses JSON data using eval is vulnerable to attack
--   unless the encoded data represents an object or an array. JSON
--   implementations in other languages conform to that same restriction to
--   preserve interoperability and security.
value :: Parser Value

-- | Parse a quoted JSON string.
jstring :: Parser Text

-- | Parse a top-level JSON value.
--   
--   This is a strict version of json which avoids building up
--   thunks during parsing; it performs all conversions immediately. Prefer
--   this version if most of the JSON data needs to be accessed.
--   
--   This function is an alias for value'. In aeson 0.8 and earlier,
--   it parsed only object or array types, in conformance with the
--   now-obsolete RFC 4627.
json' :: Parser Value

-- | Strict version of value. See also json'.
value' :: Parser Value
decodeWith :: Parser Value -> (Value -> Result a) -> ByteString -> Maybe a
decodeStrictWith :: Parser Value -> (Value -> Result a) -> ByteString -> Maybe a
eitherDecodeWith :: Parser Value -> (Value -> IResult a) -> ByteString -> Either (JSONPath, String) a
eitherDecodeStrictWith :: Parser Value -> (Value -> IResult a) -> ByteString -> Either (JSONPath, String) a

module Data.Aeson.Internal.Time

-- | Like TimeOfDay, but using a fixed-width integer for seconds.
data TimeOfDay64
TOD :: {-# UNPACK #-} !Int -> {-# UNPACK #-} !Int -> {-# UNPACK #-} !Int64 -> TimeOfDay64
fromPico :: Pico -> Integer
toPico :: Integer -> Pico
diffTimeOfDay64 :: DiffTime -> TimeOfDay64
toTimeOfDay64 :: TimeOfDay -> TimeOfDay64

-- | Internal types and functions.
--   
--   Note: all declarations in this module are unstable, and prone
--   to being changed at any time.
module Data.Aeson.Internal

-- | The internal result of running a Parser.
data IResult a
IError :: JSONPath -> String -> IResult a
ISuccess :: a -> IResult a

-- | Elements of a JSON path used to describe the location of an error.
data JSONPathElement

-- | JSON path element of a key into an object, "object.key".
Key :: Text -> JSONPathElement

-- | JSON path element of an index into an array, "array[index]".
Index :: {-# UNPACK #-} !Int -> JSONPathElement
type JSONPath = [JSONPathElement]

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

-- | Annotate an error message with a JSONPath error location.
formatError :: JSONPath -> String -> String

-- | Convert a value from JSON, failing if the types do not match.
ifromJSON :: (FromJSON a) => Value -> IResult a

-- | Run a Parser.
iparse :: (a -> Parser b) -> a -> IResult b

module Data.Aeson.Encoding.Internal

-- | An encoding of a JSON value.
--   
--   tag represents which kind of JSON the Encoding is encoding
--   to, we reuse Text and Value as tags here.
newtype Encoding' tag
Encoding :: Builder -> Encoding' tag

-- | Acquire the underlying bytestring builder.
[fromEncoding] :: Encoding' tag -> Builder

-- | Often used synonnym for Encoding'.
type Encoding = Encoding' Value
encodingToLazyByteString :: Encoding' a -> ByteString

-- | Make Encoding from Builder.
--   
--   Use with care! You have to make sure that the passed Builder is a
--   valid JSON Encoding!
unsafeToEncoding :: Builder -> Encoding' a
retagEncoding :: Encoding' a -> Encoding' b

-- | A series of values that, when encoded, should be separated by commas.
--   Since 0.11.0.0, the .= operator is overloaded to create
--   either (Text, Value) or Series. You can use Series
--   when encoding directly to a bytestring builder as in the following
--   example:
--   
--   
--   toEncoding (Person name age) = pairs ("name" .= name <> "age" .= age)
--   
data Series
Empty :: Series
Value :: (Encoding' Series) -> Series

-- | Encode a series of key/value pairs, separated by commas.
pairs :: Series -> Encoding
pair :: Text -> Encoding -> Series
pair' :: Encoding' Text -> Encoding -> Series
nullEncoding :: Encoding' a -> Bool
emptyArray_ :: Encoding
emptyObject_ :: Encoding
wrapObject :: Encoding' a -> Encoding
wrapArray :: Encoding' a -> Encoding
null_ :: Encoding
bool :: Bool -> Encoding
text :: Text -> Encoding' a
lazyText :: Text -> Encoding' a
string :: String -> Encoding' a
list :: (a -> Encoding) -> [a] -> Encoding

-- | Encode as JSON object
dict :: (k -> Encoding' Text) -> (v -> Encoding) -> (forall a. (k -> v -> a -> a) -> a -> m -> a) -> m -> Encoding

-- | Encode as a tuple.
--   
--   @ toEncoding (X a b c) = tuple $ toEncoding a >*< toEncoding b
--   >*< toEncoding c
tuple :: Encoding' InArray -> Encoding

-- | See tuple.
(>*<) :: Encoding' a -> Encoding' b -> Encoding' InArray
infixr 6 >*<

-- | Type tag for tuples contents, see tuple.
data InArray
empty :: Encoding' a
(><) :: Encoding' a -> Encoding' a -> Encoding' a
infixr 6 ><
econcat :: [Encoding' a] -> Encoding' a
int8 :: Int8 -> Encoding
int16 :: Int16 -> Encoding
int32 :: Int32 -> Encoding
int64 :: Int64 -> Encoding
int :: Int -> Encoding
word8 :: Word8 -> Encoding
word16 :: Word16 -> Encoding
word32 :: Word32 -> Encoding
word64 :: Word64 -> Encoding
word :: Word -> Encoding
integer :: Integer -> Encoding
float :: Float -> Encoding
double :: Double -> Encoding
scientific :: Scientific -> Encoding
int8Text :: Int8 -> Encoding' a
int16Text :: Int16 -> Encoding' a
int32Text :: Int32 -> Encoding' a
int64Text :: Int64 -> Encoding' a
intText :: Int -> Encoding' a
word8Text :: Word8 -> Encoding' a
word16Text :: Word16 -> Encoding' a
word32Text :: Word32 -> Encoding' a
word64Text :: Word64 -> Encoding' a
wordText :: Word -> Encoding' a
integerText :: Integer -> Encoding' a
floatText :: Float -> Encoding' a
doubleText :: Double -> Encoding' a
scientificText :: Scientific -> Encoding' a
day :: Day -> Encoding' a
localTime :: LocalTime -> Encoding' a
utcTime :: UTCTime -> Encoding' a
timeOfDay :: TimeOfDay -> Encoding' a
zonedTime :: ZonedTime -> Encoding' a
value :: Value -> Encoding
comma :: Encoding' a
colon :: Encoding' a
openBracket :: Encoding' a
closeBracket :: Encoding' a
openCurly :: Encoding' a
closeCurly :: Encoding' a
instance GHC.Show.Show (Data.Aeson.Encoding.Internal.Encoding' a)
instance GHC.Classes.Eq (Data.Aeson.Encoding.Internal.Encoding' a)
instance GHC.Classes.Ord (Data.Aeson.Encoding.Internal.Encoding' a)
instance Data.Semigroup.Semigroup Data.Aeson.Encoding.Internal.Series
instance GHC.Base.Monoid Data.Aeson.Encoding.Internal.Series

-- | Functions in this module return well-formed Encoding'.
--   Polymorphic variants, which return Encoding a, return
--   a textual JSON value, so it can be used as both Encoding'
--   Text and Encoding = Encoding'
--   Value.
module Data.Aeson.Encoding

-- | Often used synonnym for Encoding'.
type Encoding = Encoding' Value

-- | An encoding of a JSON value.
--   
--   tag represents which kind of JSON the Encoding is encoding
--   to, we reuse Text and Value as tags here.
data Encoding' tag
encodingToLazyByteString :: Encoding' a -> ByteString

-- | Acquire the underlying bytestring builder.
fromEncoding :: Encoding' tag -> Builder

-- | Make Encoding from Builder.
--   
--   Use with care! You have to make sure that the passed Builder is a
--   valid JSON Encoding!
unsafeToEncoding :: Builder -> Encoding' a

-- | A series of values that, when encoded, should be separated by commas.
--   Since 0.11.0.0, the .= operator is overloaded to create
--   either (Text, Value) or Series. You can use Series
--   when encoding directly to a bytestring builder as in the following
--   example:
--   
--   
--   toEncoding (Person name age) = pairs ("name" .= name <> "age" .= age)
--   
data Series

-- | Encode a series of key/value pairs, separated by commas.
pairs :: Series -> Encoding
pair :: Text -> Encoding -> Series
pair' :: Encoding' Text -> Encoding -> Series
nullEncoding :: Encoding' a -> Bool
emptyArray_ :: Encoding
emptyObject_ :: Encoding
text :: Text -> Encoding' a
lazyText :: Text -> Encoding' a
string :: String -> Encoding' a
list :: (a -> Encoding) -> [a] -> Encoding

-- | Encode as JSON object
dict :: (k -> Encoding' Text) -> (v -> Encoding) -> (forall a. (k -> v -> a -> a) -> a -> m -> a) -> m -> Encoding
null_ :: Encoding
bool :: Bool -> Encoding
int8 :: Int8 -> Encoding
int16 :: Int16 -> Encoding
int32 :: Int32 -> Encoding
int64 :: Int64 -> Encoding
int :: Int -> Encoding
word8 :: Word8 -> Encoding
word16 :: Word16 -> Encoding
word32 :: Word32 -> Encoding
word64 :: Word64 -> Encoding
word :: Word -> Encoding
integer :: Integer -> Encoding
float :: Float -> Encoding
double :: Double -> Encoding
scientific :: Scientific -> Encoding
int8Text :: Int8 -> Encoding' a
int16Text :: Int16 -> Encoding' a
int32Text :: Int32 -> Encoding' a
int64Text :: Int64 -> Encoding' a
intText :: Int -> Encoding' a
word8Text :: Word8 -> Encoding' a
word16Text :: Word16 -> Encoding' a
word32Text :: Word32 -> Encoding' a
word64Text :: Word64 -> Encoding' a
wordText :: Word -> Encoding' a
integerText :: Integer -> Encoding' a
floatText :: Float -> Encoding' a
doubleText :: Double -> Encoding' a
scientificText :: Scientific -> Encoding' a
day :: Day -> Encoding' a
localTime :: LocalTime -> Encoding' a
utcTime :: UTCTime -> Encoding' a
timeOfDay :: TimeOfDay -> Encoding' a
zonedTime :: ZonedTime -> Encoding' a
value :: Value -> Encoding

-- | Types for working with JSON data.
module Data.Aeson.Types

-- | A JSON value represented as a Haskell value.
data Value
Object :: !Object -> Value
Array :: !Array -> Value
String :: !Text -> Value
Number :: !Scientific -> Value
Bool :: !Bool -> Value
Null :: Value

-- | Often used synonnym for Encoding'.
type Encoding = Encoding' Value

-- | Make Encoding from Builder.
--   
--   Use with care! You have to make sure that the passed Builder is a
--   valid JSON Encoding!
unsafeToEncoding :: Builder -> Encoding' a

-- | Acquire the underlying bytestring builder.
fromEncoding :: Encoding' tag -> Builder

-- | A series of values that, when encoded, should be separated by commas.
--   Since 0.11.0.0, the .= operator is overloaded to create
--   either (Text, Value) or Series. You can use Series
--   when encoding directly to a bytestring builder as in the following
--   example:
--   
--   
--   toEncoding (Person name age) = pairs ("name" .= name <> "age" .= age)
--   
data Series

-- | A JSON "array" (sequence).
type Array = Vector Value

-- | The empty array.
emptyArray :: Value

-- | A key/value pair for an Object.
type Pair = (Text, Value)

-- | A JSON "object" (key/value map).
type Object = HashMap Text Value

-- | The empty object.
emptyObject :: Value

-- | A newtype wrapper for UTCTime that uses the same non-standard
--   serialization format as Microsoft .NET, whose System.DateTime
--   type is by default serialized to JSON as in the following example:
--   
--   
--   /Date(1302547608878)/
--   
--   
--   The number represents milliseconds since the Unix epoch.
newtype DotNetTime
DotNetTime :: UTCTime -> DotNetTime

-- | Acquire the underlying value.
[fromDotNetTime] :: DotNetTime -> UTCTime

-- | Fail parsing due to a type mismatch, with a descriptive message.
--   
--   Example usage:
--   
--   
--   instance FromJSON Coord where
--     parseJSON (Object v) = {- type matches, life is good -}
--     parseJSON wat        = typeMismatch "Coord" wat
--   
typeMismatch :: String -> Value -> Parser a

-- | A JSON parser.
data Parser a

-- | The result of running a Parser.
data Result a
Error :: String -> Result a
Success :: a -> Result a

-- | A type that can be converted from JSON, with the possibility of
--   failure.
--   
--   In many cases, you can get the compiler to generate parsing code for
--   you (see below). To begin, let's cover writing an instance by hand.
--   
--   There are various reasons a conversion could fail. For example, an
--   Object could be missing a required key, an Array could
--   be of the wrong size, or a value could be of an incompatible type.
--   
--   The basic ways to signal a failed conversion are as follows:
--   
--   
--   
- empty and mzero work, but are terse and
--   uninformative;
--   
- fail yields a custom error message;
--   
- typeMismatch produces an informative message for cases when
--   the value encountered is not of the expected type.
--   
--   
--   An example type and instance using typeMismatch:
--   
--   
--   -- Allow ourselves to write Text literals.
--   {-# LANGUAGE OverloadedStrings #-}
--   
--   data Coord = Coord { x :: Double, y :: Double }
--   
--   instance FromJSON Coord where
--       parseJSON (Object v) = Coord
--           <$> v .: "x"
--           <*> v .: "y"
--   
--       -- We do not expect a non-Object value here.
--       -- We could use mzero to fail, but typeMismatch
--       -- gives a much more informative error message.
--       parseJSON invalid    = typeMismatch "Coord" invalid
--   
--   
--   For this common case of only being concerned with a single type of
--   JSON value, the functions withObject, withNumber, etc.
--   are provided. Their use is to be preferred when possible, since they
--   are more terse. Using withObject, we can rewrite the above
--   instance (assuming the same language extension and data type) as:
--   
--   
--   instance FromJSON Coord where
--       parseJSON = withObject "Coord" $ v -> Coord
--           <$> v .: "x"
--           <*> v .: "y"
--   
--   
--   Instead of manually writing your FromJSON instance, there are
--   two options to do it automatically:
--   
--   
--   
- Data.Aeson.TH provides Template Haskell functions which
--   will derive an instance at compile time. The generated instance is
--   optimized for your type so it will probably be more efficient than the
--   following option.
--   
- The compiler can provide a default generic implementation for
--   parseJSON.
--   
--   
--   To use the second, simply add a deriving Generic
--   clause to your datatype and declare a FromJSON instance for
--   your datatype without giving a definition for parseJSON.
--   
--   For example, the previous example can be simplified to just:
--   
--   
--   {-# LANGUAGE DeriveGeneric #-}
--   
--   import GHC.Generics
--   
--   data Coord = Coord { x :: Double, y :: Double } deriving Generic
--   
--   instance FromJSON Coord
--   
--   
--   The default implementation will be equivalent to parseJSON =
--   genericParseJSON defaultOptions; If you need
--   different options, you can customize the generic decoding by defining:
--   
--   
--   customOptions = defaultOptions
--                   { fieldLabelModifier = map toUpper
--                   }
--   
--   instance FromJSON Coord where
--       parseJSON = genericParseJSON customOptions
--   
class FromJSON a where parseJSON = genericParseJSON defaultOptions parseJSONList (Array a) = zipWithM (parseIndexedJSON parseJSON) [0 .. ] . toList $ a parseJSONList v = typeMismatch "[a]" v
parseJSON :: FromJSON a => Value -> Parser a
parseJSON :: (FromJSON a, Generic a, GFromJSON Zero (Rep a)) => Value -> Parser a
parseJSONList :: FromJSON a => Value -> Parser [a]

-- | Convert a value from JSON, failing if the types do not match.
fromJSON :: (FromJSON a) => Value -> Result a

-- | Run a Parser.
parse :: (a -> Parser b) -> a -> Result b

-- | Run a Parser with an Either result type. If the parse
--   fails, the Left payload will contain an error message.
parseEither :: (a -> Parser b) -> a -> Either String b

-- | Run a Parser with a Maybe result type.
parseMaybe :: (a -> Parser b) -> a -> Maybe b

-- | A type that can be converted to JSON.
--   
--   Instances in general must specify toJSON and
--   should (but don't need to) specify toEncoding.
--   
--   An example type and instance:
--   
--   
--   -- Allow ourselves to write Text literals.
--   {-# LANGUAGE OverloadedStrings #-}
--   
--   data Coord = Coord { x :: Double, y :: Double }
--   
--   instance ToJSON Coord where
--     toJSON (Coord x y) = object ["x" .= x, "y" .= y]
--   
--     toEncoding (Coord x y) = pairs ("x" .= x <> "y" .= y)
--   
--   
--   Instead of manually writing your ToJSON instance, there are two
--   options to do it automatically:
--   
--   
--   
- Data.Aeson.TH provides Template Haskell functions which
--   will derive an instance at compile time. The generated instance is
--   optimized for your type so it will probably be more efficient than the
--   following option.
--   
- The compiler can provide a default generic implementation for
--   toJSON.
--   
--   
--   To use the second, simply add a deriving Generic
--   clause to your datatype and declare a ToJSON instance. If you
--   require nothing other than defaultOptions, it is sufficient to
--   write (and this is the only alternative where the default
--   toJSON implementation is sufficient):
--   
--   
--   {-# LANGUAGE DeriveGeneric #-}
--   
--   import GHC.Generics
--   
--   data Coord = Coord { x :: Double, y :: Double } deriving Generic
--   
--   instance ToJSON Coord where
--       toEncoding = genericToEncoding defaultOptions
--   
--   
--   If on the other hand you wish to customize the generic decoding, you
--   have to implement both methods:
--   
--   
--   customOptions = defaultOptions
--                   { fieldLabelModifier = map toUpper
--                   }
--   
--   instance ToJSON Coord where
--       toJSON     = genericToJSON customOptions
--       toEncoding = genericToEncoding customOptions
--   
--   
--   Previous versions of this library only had the toJSON method.
--   Adding toEncoding had to reasons:
--   
--   
--   
- toEncoding is more efficient for the common case that the output
--   of toJSON is directly serialized to a ByteString.
--   Further, expressing either method in terms of the other would be
--   non-optimal.
--   
- The choice of defaults allows a smooth transition for existing
--   users: Existing instances that do not define toEncoding still
--   compile and have the correct semantics. This is ensured by making the
--   default implementation of toEncoding use toJSON. This
--   produces correct results, but since it performs an intermediate
--   conversion to a Value, it will be less efficient than directly
--   emitting an Encoding. (this also means that specifying nothing
--   more than instance ToJSON Coord would be sufficient as a
--   generically decoding instance, but there probably exists no good
--   reason to not specify toEncoding in new instances.)
--   
class ToJSON a where toJSON = genericToJSON defaultOptions toEncoding = value . toJSON toJSONList = listValue toJSON toEncodingList = listEncoding toEncoding

-- | Convert a Haskell value to a JSON-friendly intermediate type.
toJSON :: ToJSON a => a -> Value

-- | Convert a Haskell value to a JSON-friendly intermediate type.
toJSON :: (ToJSON a, Generic a, GToJSON Zero (Rep a)) => a -> Value

-- | Encode a Haskell value as JSON.
--   
--   The default implementation of this method creates an intermediate
--   Value using toJSON. This provides source-level
--   compatibility for people upgrading from older versions of this
--   library, but obviously offers no performance advantage.
--   
--   To benefit from direct encoding, you must provide an
--   implementation for this method. The easiest way to do so is by having
--   your types implement Generic using the DeriveGeneric
--   extension, and then have GHC generate a method body as follows.
--   
--   
--   instance ToJSON Coord where
--       toEncoding = genericToEncoding defaultOptions
--   
toEncoding :: ToJSON a => a -> Encoding
toJSONList :: ToJSON a => [a] -> Value
toEncodingList :: ToJSON a => [a] -> Encoding

-- | A key-value pair for encoding a JSON object.
class KeyValue kv
(.=) :: (KeyValue kv, ToJSON v) => Text -> v -> kv

-- | If the inner Parser failed, modify the failure message using
--   the provided function. This allows you to create more descriptive
--   error messages. For example:
--   
--   
--   parseJSON (Object o) = modifyFailure
--       ("Parsing of the Foo value failed: " ++)
--       (Foo <$> o .: "someField")
--   
--   
--   Since 0.6.2.0
modifyFailure :: (String -> String) -> Parser a -> Parser a

-- | Typeclass for types that can be used as the key of a map-like
--   container (like Map or HashMap). For example, since
--   Text has a ToJSONKey instance and Char has a
--   ToJSON instance, we can encode a value of type Map
--   Text Char:
--   
--   
--   >>> LBC8.putStrLn $ encode $ Map.fromList [("foo" :: Text, 'a')]
--   {"foo":"a"}
--   
--   
--   Since Int also has a ToJSONKey instance, we can
--   similarly write:
--   
--   
--   >>> LBC8.putStrLn $ encode $ Map.fromList [(5 :: Int, 'a')]
--   {"5":"a"}
--   
--   
--   JSON documents only accept strings as object keys. For any type from
--   base that has a natural textual representation, it can be
--   expected that its ToJSONKey instance will choose that
--   representation.
--   
--   For data types that lack a natural textual representation, an
--   alternative is provided. The map-like container is represented as a
--   JSON array instead of a JSON object. Each value in the array is an
--   array with exactly two values. The first is the key and the second is
--   the value.
--   
--   For example, values of type '[Text]' cannot be encoded to a string, so
--   a Map with keys of type '[Text]' is encoded as follows:
--   
--   
--   >>> LBC8.putStrLn $ encode $ Map.fromList [(["foo","bar","baz" :: Text], 'a')]
--   [[["foo","bar","baz"],"a"]]
--   
--   
--   The default implementation of ToJSONKey chooses this method of
--   encoding a key, using the ToJSON instance of the type.
--   
--   To use your own data type as the key in a map, all that is needed is
--   to write a ToJSONKey (and possibly a FromJSONKey)
--   instance for it. If the type cannot be trivially converted to and from
--   Text, it is recommended that ToJSONKeyValue is used.
--   Since the default implementations of the typeclass methods can build
--   this from a ToJSON instance, there is nothing that needs to be
--   written:
--   
--   
--   data Foo = Foo { fooAge :: Int, fooName :: Text }
--     deriving (Eq,Ord,Generic)
--   instance ToJSON Foo
--   instance ToJSONKey Foo
--   
--   
--   That's it. We can now write:
--   
--   
--   >>> let m = Map.fromList [(Foo 4 "bar",'a'),(Foo 6 "arg",'b')]
--   
--   >>> LBC8.putStrLn $ encode m
--   [[{"fooName":"bar","fooAge":4},"a"],[{"fooName":"arg","fooAge":6},"b"]]
--   
--   
--   The next case to consider is if we have a type that is a newtype
--   wrapper around Text. The recommended approach is to use
--   generalized newtype deriving:
--   
--   
--   newtype RecordId = RecordId { getRecordId :: Text}
--     deriving (Eq,Ord,ToJSONKey)
--   
--   
--   Then we may write:
--   
--   
--   >>> LBC8.putStrLn $ encode $ Map.fromList [(RecordId "abc",'a')]
--   {"abc":"a"}
--   
--   
--   Simple sum types are a final case worth considering. Suppose we have:
--   
--   
--   data Color = Red | Green | Blue
--     deriving (Show,Read,Eq,Ord)
--   
--   
--   It is possible to get the ToJSONKey instance for free as we did
--   with Foo. However, in this case, we have a natural way to go
--   to and from Text that does not require any escape sequences.
--   So, in this example, ToJSONKeyText will be used instead of
--   ToJSONKeyValue. The Show instance can be used to help
--   write ToJSONKey:
--   
--   
--   instance ToJSONKey Color where
--     toJSONKey = ToJSONKeyText f g
--       where f = Text.pack . show
--             g = text . Text.pack . show
--             -- text function is from Data.Aeson.Encoding
--   
--   
--   The situation of needing to turning function a -> Text
--   into a ToJSONKeyFunction is common enough that a special
--   combinator is provided for it. The above instance can be rewritten as:
--   
--   
--   instance ToJSONKey Color where
--     toJSONKey = toJSONKeyText (Text.pack . show)
--   
--   
--   The performance of the above instance can be improved by not using
--   String as an intermediate step when converting to Text.
--   One option for improving performance would be to use template haskell
--   machinery from the text-show package. However, even with the
--   approach, the Encoding (a wrapper around a bytestring builder)
--   is generated by encoding the Text to a ByteString, an
--   intermediate step that could be avoided. The fastest possible
--   implementation would be:
--   
--   
--   -- Assuming that OverloadedStrings is enabled
--   instance ToJSONKey Color where
--     toJSONKey = ToJSONKeyText f g
--       where f x = case x of {Red -> "Red";Green ->"Green";Blue -> "Blue"}
--             g x = case x of {Red -> text "Red";Green -> text "Green";Blue -> text "Blue"}
--             -- text function is from Data.Aeson.Encoding
--   
--   
--   This works because GHC can lift the encoded values out of the case
--   statements, which means that they are only evaluated once. This
--   approach should only be used when there is a serious need to maximize
--   performance.
class ToJSONKey a where toJSONKey = ToJSONKeyValue toJSON toEncoding toJSONKeyList = ToJSONKeyValue toJSON toEncoding

-- | Strategy for rendering the key for a map-like container.
toJSONKey :: ToJSONKey a => ToJSONKeyFunction a

-- | Strategy for rendering the key for a map-like container.
toJSONKey :: (ToJSONKey a, ToJSON a) => ToJSONKeyFunction a

-- | This is similar in spirit to the showsList method of
--   Show. It makes it possible to give String keys special
--   treatment without using OverlappingInstances. End users
--   should always be able to use the default implementation of this
--   method.
toJSONKeyList :: ToJSONKey a => ToJSONKeyFunction [a]

-- | This is similar in spirit to the showsList method of
--   Show. It makes it possible to give String keys special
--   treatment without using OverlappingInstances. End users
--   should always be able to use the default implementation of this
--   method.
toJSONKeyList :: (ToJSONKey a, ToJSON a) => ToJSONKeyFunction [a]
data ToJSONKeyFunction a

-- | key is encoded to string, produces object
ToJSONKeyText :: !(a -> Text) -> !(a -> Encoding' Text) -> ToJSONKeyFunction a

-- | key is encoded to value, produces array
ToJSONKeyValue :: !(a -> Value) -> !(a -> Encoding) -> ToJSONKeyFunction a

-- | Helper for creating textual keys.
--   
--   
--   instance ToJSONKey MyKey where
--       toJSONKey = toJSONKeyText myKeyToText
--         where
--           myKeyToText = Text.pack . show -- or showt from text-show
--   
toJSONKeyText :: (a -> Text) -> ToJSONKeyFunction a

-- | Contravariant map, as ToJSONKeyFunction is a contravariant
--   functor.
contramapToJSONKeyFunction :: (b -> a) -> ToJSONKeyFunction a -> ToJSONKeyFunction b

-- | Read the docs for ToJSONKey first. This class is a conversion
--   in the opposite direction. If you have a newtype wrapper around
--   Text, the recommended way to define instances is with
--   generalized newtype deriving:
--   
--   
--   newtype SomeId = SomeId { getSomeId :: Text }
--     deriving (Eq,Ord,Hashable,FromJSONKey)
--   
class FromJSONKey a where fromJSONKey = FromJSONKeyValue parseJSON fromJSONKeyList = FromJSONKeyValue parseJSON

-- | Strategy for parsing the key of a map-like container.
fromJSONKey :: FromJSONKey a => FromJSONKeyFunction a

-- | Strategy for parsing the key of a map-like container.
fromJSONKey :: (FromJSONKey a, FromJSON a) => FromJSONKeyFunction a

-- | This is similar in spirit to the readList method of
--   Read. It makes it possible to give String keys special
--   treatment without using OverlappingInstances. End users
--   should always be able to use the default implementation of this
--   method.
fromJSONKeyList :: FromJSONKey a => FromJSONKeyFunction [a]

-- | This is similar in spirit to the readList method of
--   Read. It makes it possible to give String keys special
--   treatment without using OverlappingInstances. End users
--   should always be able to use the default implementation of this
--   method.
fromJSONKeyList :: (FromJSONKey a, FromJSON a) => FromJSONKeyFunction [a]

-- | This type is related to ToJSONKeyFunction. If
--   FromJSONKeyValue is used in the FromJSONKey instance,
--   then ToJSONKeyValue should be used in the ToJSONKey
--   instance. The other three data constructors for this type all
--   correspond to ToJSONKeyText. Strictly speaking,
--   FromJSONKeyTextParser is more powerful than
--   FromJSONKeyText, which is in turn more powerful than
--   FromJSONKeyCoerce. For performance reasons, these exist as
--   three options instead of one.
data FromJSONKeyFunction a

-- | uses coerce (unsafeCoerce in older GHCs)
FromJSONKeyCoerce :: !(CoerceText a) -> FromJSONKeyFunction a

-- | conversion from Text that always succeeds
FromJSONKeyText :: !(Text -> a) -> FromJSONKeyFunction a

-- | conversion from Text that may fail
FromJSONKeyTextParser :: !(Text -> Parser a) -> FromJSONKeyFunction a

-- | conversion for non-textual keys
FromJSONKeyValue :: !(Value -> Parser a) -> FromJSONKeyFunction a

-- | Construct FromJSONKeyFunction for types coercible from
--   Text. This conversion is still unsafe, as Hashable and
--   Eq instances of a should be compatible with
--   Text i.e. hash values should be equal for wrapped values as
--   well. This property will always be maintained if the Hashable
--   and Eq instances are derived with generalized newtype deriving.
--   compatible with Text i.e. hash values be equal for wrapped
--   values as well.
--   
--   On pre GHC 7.8 this is unconstrainted function.
fromJSONKeyCoerce :: Coercible Text a => FromJSONKeyFunction a

-- | Semantically the same as coerceFromJSONKeyFunction = fmap coerce =
--   coerce.
--   
--   See note on fromJSONKeyCoerce.
coerceFromJSONKeyFunction :: Coercible a b => FromJSONKeyFunction a -> FromJSONKeyFunction b

-- | Same as fmap. Provided for the consistency with
--   ToJSONKeyFunction.
mapFromJSONKeyFunction :: (a -> b) -> FromJSONKeyFunction a -> FromJSONKeyFunction b

-- | Lifting of the FromJSON class to unary type constructors.
--   
--   Instead of manually writing your FromJSON1 instance, there are
--   two options to do it automatically:
--   
--   
--   
- Data.Aeson.TH provides Template Haskell functions which
--   will derive an instance at compile time. The generated instance is
--   optimized for your type so it will probably be more efficient than the
--   following option.
--   
- The compiler can provide a default generic implementation for
--   liftParseJSON.
--   
--   
--   To use the second, simply add a deriving Generic1
--   clause to your datatype and declare a FromJSON1 instance for
--   your datatype without giving a definition for liftParseJSON.
--   
--   For example:
--   
--   
--   {-# LANGUAGE DeriveGeneric #-}
--   
--   import GHC.Generics
--   
--   data Pair a b = Pair { pairFst :: a, pairSnd :: b } deriving Generic1
--   
--   instance FromJSON a => FromJSON1 (Pair a)
--   
--   
--   If the default implementation doesn't give exactly the results you
--   want, you can customize the generic decoding with only a tiny amount
--   of effort, using genericLiftParseJSON with your preferred
--   Options:
--   
--   
--   customOptions = defaultOptions
--                   { fieldLabelModifier = map toUpper
--                   }
--   
--   instance FromJSON a => FromJSON1 (Pair a) where
--       liftParseJSON = genericLiftParseJSON customOptions
--   
class FromJSON1 f where liftParseJSON = genericLiftParseJSON defaultOptions liftParseJSONList f g v = listParser (liftParseJSON f g) v
liftParseJSON :: FromJSON1 f => (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (f a)
liftParseJSON :: (FromJSON1 f, Generic1 f, GFromJSON One (Rep1 f)) => (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (f a)
liftParseJSONList :: FromJSON1 f => (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [f a]

-- | Lift the standard parseJSON function through the type
--   constructor.
parseJSON1 :: (FromJSON1 f, FromJSON a) => Value -> Parser (f a)

-- | Lifting of the FromJSON class to binary type constructors.
--   
--   Instead of manually writing your FromJSON2 instance,
--   Data.Aeson.TH provides Template Haskell functions which will
--   derive an instance at compile time.
class FromJSON2 f where liftParseJSONList2 fa ga fb gb v = case v of { Array vals -> fmap toList (mapM (liftParseJSON2 fa ga fb gb) vals) _ -> typeMismatch "[a]" v }
liftParseJSON2 :: FromJSON2 f => (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser (f a b)
liftParseJSONList2 :: FromJSON2 f => (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser [f a b]

-- | Lift the standard parseJSON function through the type
--   constructor.
parseJSON2 :: (FromJSON2 f, FromJSON a, FromJSON b) => Value -> Parser (f a b)

-- | Lifting of the ToJSON class to unary type constructors.
--   
--   Instead of manually writing your ToJSON1 instance, there are
--   two options to do it automatically:
--   
--   
--   
- Data.Aeson.TH provides Template Haskell functions which
--   will derive an instance at compile time. The generated instance is
--   optimized for your type so it will probably be more efficient than the
--   following option.
--   
- The compiler can provide a default generic implementation for
--   toJSON1.
--   
--   
--   To use the second, simply add a deriving Generic1
--   clause to your datatype and declare a ToJSON1 instance for your
--   datatype without giving definitions for liftToJSON or
--   liftToEncoding.
--   
--   For example:
--   
--   
--   {-# LANGUAGE DeriveGeneric #-}
--   
--   import GHC.Generics
--   
--   data Pair = Pair { pairFst :: a, pairSnd :: b } deriving Generic1
--   
--   instance ToJSON a => ToJSON1 (Pair a)
--   
--   
--   If the default implementation doesn't give exactly the results you
--   want, you can customize the generic encoding with only a tiny amount
--   of effort, using genericLiftToJSON and
--   genericLiftToEncoding with your preferred Options:
--   
--   
--   customOptions = defaultOptions
--                   { fieldLabelModifier = map toUpper
--                   }
--   
--   instance ToJSON a => ToJSON1 (Pair a) where
--       liftToJSON     = genericLiftToJSON customOptions
--       liftToEncoding = genericLiftToEncoding customOptions
--   
--   
--   See also ToJSON.
class ToJSON1 f where liftToJSON = genericLiftToJSON defaultOptions liftToJSONList f g = listValue (liftToJSON f g) liftToEncoding = genericLiftToEncoding defaultOptions liftToEncodingList f g = listEncoding (liftToEncoding f g)
liftToJSON :: ToJSON1 f => (a -> Value) -> ([a] -> Value) -> f a -> Value
liftToJSON :: (ToJSON1 f, Generic1 f, GToJSON One (Rep1 f)) => (a -> Value) -> ([a] -> Value) -> f a -> Value
liftToJSONList :: ToJSON1 f => (a -> Value) -> ([a] -> Value) -> [f a] -> Value
liftToEncoding :: ToJSON1 f => (a -> Encoding) -> ([a] -> Encoding) -> f a -> Encoding
liftToEncoding :: (ToJSON1 f, Generic1 f, GToEncoding One (Rep1 f)) => (a -> Encoding) -> ([a] -> Encoding) -> f a -> Encoding
liftToEncodingList :: ToJSON1 f => (a -> Encoding) -> ([a] -> Encoding) -> [f a] -> Encoding

-- | Lift the standard toJSON function through the type constructor.
toJSON1 :: (ToJSON1 f, ToJSON a) => f a -> Value

-- | Lift the standard toEncoding function through the type
--   constructor.
toEncoding1 :: (ToJSON1 f, ToJSON a) => f a -> Encoding

-- | Lifting of the ToJSON class to binary type constructors.
--   
--   Instead of manually writing your ToJSON2 instance,
--   Data.Aeson.TH provides Template Haskell functions which will
--   derive an instance at compile time.
--   
--   The compiler cannot provide a default generic implementation for
--   liftToJSON2, unlike toJSON and liftToJSON.
class ToJSON2 f where liftToJSONList2 fa ga fb gb = listValue (liftToJSON2 fa ga fb gb) liftToEncodingList2 fa ga fb gb = listEncoding (liftToEncoding2 fa ga fb gb)
liftToJSON2 :: ToJSON2 f => (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> f a b -> Value
liftToJSONList2 :: ToJSON2 f => (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> [f a b] -> Value
liftToEncoding2 :: ToJSON2 f => (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> f a b -> Encoding
liftToEncodingList2 :: ToJSON2 f => (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> [f a b] -> Encoding

-- | Lift the standard toJSON function through the type constructor.
toJSON2 :: (ToJSON2 f, ToJSON a, ToJSON b) => f a b -> Value

-- | Lift the standard toEncoding function through the type
--   constructor.
toEncoding2 :: (ToJSON2 f, ToJSON a, ToJSON b) => f a b -> Encoding

-- | Class of generic representation types that can be converted from JSON.
class GFromJSON arity f

-- | This method (applied to defaultOptions) is used as the default
--   generic implementation of parseJSON (if the arity is
--   Zero) or liftParseJSON (if the arity is
--   One).
gParseJSON :: GFromJSON arity f => Options -> FromArgs arity a -> Value -> Parser (f a)

-- | A FromArgs value either stores nothing (for FromJSON) or
--   it stores the two function arguments that decode occurrences of the
--   type parameter (for FromJSON1).
data FromArgs arity a
[NoFromArgs] :: FromArgs Zero a
[From1Args] :: (Value -> Parser a) -> (Value -> Parser [a]) -> FromArgs One a

-- | Class of generic representation types that can be converted to JSON.
class GToJSON arity f

-- | This method (applied to defaultOptions) is used as the default
--   generic implementation of toJSON (if the arity is
--   Zero) or liftToJSON (if the arity is
--   One).
gToJSON :: GToJSON arity f => Options -> ToArgs Value arity a -> f a -> Value

-- | Class of generic representation types that can be converted to a JSON
--   Encoding.
class GToEncoding arity f

-- | This method (applied to defaultOptions) can be used as the
--   default generic implementation of toEncoding (if the
--   arity is Zero) or liftToEncoding (if the
--   arity is One).
gToEncoding :: GToEncoding arity f => Options -> ToArgs Encoding arity a -> f a -> Encoding

-- | A ToArgs value either stores nothing (for ToJSON) or it
--   stores the two function arguments that encode occurrences of the type
--   parameter (for ToJSON1).
data ToArgs res arity a
[NoToArgs] :: ToArgs res Zero a
[To1Args] :: (a -> res) -> ([a] -> res) -> ToArgs res One a

-- | A type-level indicator that ToJSON or FromJSON is
--   being derived generically.
data Zero

-- | A type-level indicator that ToJSON1 or FromJSON1 is
--   being derived generically.
data One

-- | A configurable generic JSON creator. This function applied to
--   defaultOptions is used as the default for toJSON when
--   the type is an instance of Generic.
genericToJSON :: (Generic a, GToJSON Zero (Rep a)) => Options -> a -> Value

-- | A configurable generic JSON creator. This function applied to
--   defaultOptions is used as the default for liftToJSON
--   when the type is an instance of Generic1.
genericLiftToJSON :: (Generic1 f, GToJSON One (Rep1 f)) => Options -> (a -> Value) -> ([a] -> Value) -> f a -> Value

-- | A configurable generic JSON encoder. This function applied to
--   defaultOptions is used as the default for toEncoding
--   when the type is an instance of Generic.
genericToEncoding :: (Generic a, GToEncoding Zero (Rep a)) => Options -> a -> Encoding

-- | A configurable generic JSON encoder. This function applied to
--   defaultOptions is used as the default for liftToEncoding
--   when the type is an instance of Generic1.
genericLiftToEncoding :: (Generic1 f, GToEncoding One (Rep1 f)) => Options -> (a -> Encoding) -> ([a] -> Encoding) -> f a -> Encoding

-- | A configurable generic JSON decoder. This function applied to
--   defaultOptions is used as the default for parseJSON when
--   the type is an instance of Generic.
genericParseJSON :: (Generic a, GFromJSON Zero (Rep a)) => Options -> Value -> Parser a

-- | A configurable generic JSON decoder. This function applied to
--   defaultOptions is used as the default for liftParseJSON
--   when the type is an instance of Generic1.
genericLiftParseJSON :: (Generic1 f, GFromJSON One (Rep1 f)) => Options -> (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (f a)

-- | withObject expected f value applies f to the
--   Object when value is an Object and fails using
--   typeMismatch expected otherwise.
withObject :: String -> (Object -> Parser a) -> Value -> Parser a

-- | withText expected f value applies f to the
--   Text when value is a String and fails using
--   typeMismatch expected otherwise.
withText :: String -> (Text -> Parser a) -> Value -> Parser a

-- | withArray expected f value applies f to the
--   Array when value is an Array and fails using
--   typeMismatch expected otherwise.
withArray :: String -> (Array -> Parser a) -> Value -> Parser a

-- | withNumber expected f value applies f to the
--   Number when value is a Number and fails using
--   typeMismatch expected otherwise.

-- | Deprecated: Use withScientific instead
withNumber :: String -> (Number -> Parser a) -> Value -> Parser a

-- | withScientific expected f value applies f to
--   the Scientific number when value is a Number
--   and fails using typeMismatch expected otherwise.
withScientific :: String -> (Scientific -> Parser a) -> Value -> Parser a

-- | withBool expected f value applies f to the
--   Bool when value is a Bool and fails using
--   typeMismatch expected otherwise.
withBool :: String -> (Bool -> Parser a) -> Value -> Parser a

-- | Encode a series of key/value pairs, separated by commas.
pairs :: Series -> Encoding

-- | Encode a Foldable as a JSON array.
foldable :: (Foldable t, ToJSON a) => t a -> Encoding

-- | Retrieve the value associated with the given key of an Object.
--   The result is empty if the key is not present or the value
--   cannot be converted to the desired type.
--   
--   This accessor is appropriate if the key and value must be
--   present in an object for it to be valid. If the key and value are
--   optional, use .:? instead.
(.:) :: (FromJSON a) => Object -> Text -> Parser a

-- | Retrieve the value associated with the given key of an Object.
--   The result is Nothing if the key is not present or if its value
--   is Null, or empty if the value cannot be converted to
--   the desired type.
--   
--   This accessor is most useful if the key and value can be absent from
--   an object without affecting its validity. If the key and value are
--   mandatory, use .: instead.
(.:?) :: (FromJSON a) => Object -> Text -> Parser (Maybe a)

-- | Retrieve the value associated with the given key of an Object.
--   The result is Nothing if the key is not present or
--   empty if the value cannot be converted to the desired type.
--   
--   This differs from .:? by attempting to parse Null the
--   same as any other JSON value, instead of interpreting it as
--   Nothing.
(.:!) :: (FromJSON a) => Object -> Text -> Parser (Maybe a)

-- | Helper for use in combination with .:? to provide default
--   values for optional JSON object fields.
--   
--   This combinator is most useful if the key and value can be absent from
--   an object without affecting its validity and we know a default value
--   to assign in that case. If the key and value are mandatory, use
--   .: instead.
--   
--   Example usage:
--   
--   
--   v1 <- o .:? "opt_field_with_dfl" .!= "default_val"
--   v2 <- o .:  "mandatory_field"
--   v3 <- o .:? "opt_field2"
--   
(.!=) :: Parser (Maybe a) -> a -> Parser a

-- | Create a Value from a list of name/value Pairs. If
--   duplicate keys arise, earlier keys and their associated values win.
object :: [Pair] -> Value

-- | Function variant of .:.
parseField :: (FromJSON a) => Object -> Text -> Parser a

-- | Function variant of .:?.
parseFieldMaybe :: (FromJSON a) => Object -> Text -> Parser (Maybe a)

-- | Function variant of .:!.
parseFieldMaybe' :: (FromJSON a) => Object -> Text -> Parser (Maybe a)

-- | Variant of .: with explicit parser function.
--   
--   E.g. explicitParseField parseJSON1 ::
--   (FromJSON1 f, FromJSON a) -> Object ->
--   Text -> Parser (f a)
explicitParseField :: (Value -> Parser a) -> Object -> Text -> Parser a

-- | Variant of .:? with explicit parser function.
explicitParseFieldMaybe :: (Value -> Parser a) -> Object -> Text -> Parser (Maybe a)

-- | Variant of .:! with explicit parser function.
explicitParseFieldMaybe' :: (Value -> Parser a) -> Object -> Text -> Parser (Maybe a)

-- | Helper function to use with liftToEncoding. Useful when writing
--   own ToJSON1 instances.
--   
--   
--   newtype F a = F [a]
--   
--   -- This instance encodes String as an array of chars
--   instance ToJSON1 F where
--       liftToJSON     tj _ (F xs) = liftToJSON     tj (listValue    tj) xs
--       liftToEncoding te _ (F xs) = liftToEncoding te (listEncoding te) xs
--   
--   instance FromJSON1 F where
--       liftParseJSON p _ v = F <$> liftParseJSON p (listParser p) v
--   
listEncoding :: (a -> Encoding) -> [a] -> Encoding

-- | Helper function to use with liftToJSON, see
--   listEncoding.
listValue :: (a -> Value) -> [a] -> Value

-- | Helper function to use with liftParseJSON. See
--   listEncoding.
listParser :: (Value -> Parser a) -> Value -> Parser [a]

-- | Options that specify how to encode/decode your datatype to/from JSON.
data Options
Options :: (String -> String) -> (String -> String) -> Bool -> Bool -> SumEncoding -> Bool -> Options

-- | Function applied to field labels. Handy for removing common record
--   prefixes for example.
[fieldLabelModifier] :: Options -> String -> String

-- | Function applied to constructor tags which could be handy for
--   lower-casing them for example.
[constructorTagModifier] :: Options -> String -> String

-- | If True the constructors of a datatype, with all nullary
--   constructors, will be encoded to just a string with the constructor
--   tag. If False the encoding will always follow the
--   sumEncoding.
[allNullaryToStringTag] :: Options -> Bool

-- | If True record fields with a Nothing value will be
--   omitted from the resulting object. If False the resulting
--   object will include those fields mapping to null.
[omitNothingFields] :: Options -> Bool

-- | Specifies how to encode constructors of a sum datatype.
[sumEncoding] :: Options -> SumEncoding

-- | Hide the field name when a record constructor has only one field, like
--   a newtype.
[unwrapUnaryRecords] :: Options -> Bool

-- | Specifies how to encode constructors of a sum datatype.
data SumEncoding

-- | A constructor will be encoded to an object with a field
--   tagFieldName which specifies the constructor tag (modified by
--   the constructorTagModifier). If the constructor is a record the
--   encoded record fields will be unpacked into this object. So make sure
--   that your record doesn't have a field with the same label as the
--   tagFieldName. Otherwise the tag gets overwritten by the encoded
--   value of that field! If the constructor is not a record the encoded
--   constructor contents will be stored under the contentsFieldName
--   field.
TaggedObject :: String -> String -> SumEncoding
[tagFieldName] :: SumEncoding -> String
[contentsFieldName] :: SumEncoding -> String

-- | Constructor names won't be encoded. Instead only the contents of the
--   constructor will be encoded as if the type had a single constructor.
--   JSON encodings have to be disjoint for decoding to work properly.
--   
--   When decoding, constructors are tried in the order of definition. If
--   some encodings overlap, the first one defined will succeed.
--   
--   Note: Nullary constructors are encoded as strings (using
--   constructorTagModifier). Having a nullary constructor alongside
--   a single field constructor that encodes to a string leads to
--   ambiguity.
--   
--   Note: Only the last error is kept when decoding, so in the case
--   of malformed JSON, only an error for the last constructor will be
--   reported.
UntaggedValue :: SumEncoding

-- | A constructor will be encoded to an object with a single field named
--   after the constructor tag (modified by the
--   constructorTagModifier) which maps to the encoded contents of
--   the constructor.
ObjectWithSingleField :: SumEncoding

-- | A constructor will be encoded to a 2-element array where the first
--   element is the tag of the constructor (modified by the
--   constructorTagModifier) and the second element the encoded
--   contents of the constructor.
TwoElemArray :: SumEncoding

-- | Converts from CamelCase to another lower case, interspersing the
--   character between all capital letters and their previous entries,
--   except those capital letters that appear together, like API.
--   
--   For use by Aeson template haskell calls.
--   
--   
--   camelTo '_' 'CamelCaseAPI' == "camel_case_api"
--   

-- | Deprecated: Use camelTo2 for better results
camelTo :: Char -> String -> String

-- | Better version of camelTo. Example where it works better:
--   
--   
--   camelTo '_' 'CamelAPICase' == "camel_apicase"
--   camelTo2 '_' 'CamelAPICase' == "camel_api_case"
--   
camelTo2 :: Char -> String -> String

-- | Default encoding Options:
--   
--   
--   Options
--   { fieldLabelModifier      = id
--   , constructorTagModifier  = id
--   , allNullaryToStringTag   = True
--   , omitNothingFields       = False
--   , sumEncoding             = defaultTaggedObject
--   , unwrapUnaryRecords      = False
--   }
--   
defaultOptions :: Options

-- | Default TaggedObject SumEncoding options:
--   
--   
--   defaultTaggedObject = TaggedObject
--                         { tagFieldName      = "tag"
--                         , contentsFieldName = "contents"
--                         }
--   
defaultTaggedObject :: SumEncoding

-- | Most frequently, you'll probably want to encode straight to UTF-8 (the
--   standard JSON encoding) using encode.
--   
--   You can use the conversions to Builders when embedding JSON
--   messages as parts of a protocol.
module Data.Aeson.Text

-- | Encode a JSON Value to a Data.Text.Lazy
--   
--   Note: uses toEncoding
encodeToLazyText :: ToJSON a => a -> Text

-- | Encode a JSON Value to a Data.Text Builder, which
--   can be embedded efficiently in a text-based protocol.
--   
--   If you are going to immediately encode straight to a
--   ByteString, it is more efficient to use
--   encodeToBuilder instead.
--   
--   Note: Uses toJSON
encodeToTextBuilder :: ToJSON a => a -> Builder

-- | Types and functions for working efficiently with JSON data.
--   
--   (A note on naming: in Greek mythology, Aeson was the father of Jason.)
module Data.Aeson

-- | Efficiently deserialize a JSON value from a lazy ByteString. If
--   this fails due to incomplete or invalid input, Nothing is
--   returned.
--   
--   The input must consist solely of a JSON document, with no trailing
--   data except for whitespace.
--   
--   This function parses immediately, but defers conversion. See
--   json for details.
decode :: (FromJSON a) => ByteString -> Maybe a

-- | Efficiently deserialize a JSON value from a lazy ByteString. If
--   this fails due to incomplete or invalid input, Nothing is
--   returned.
--   
--   The input must consist solely of a JSON document, with no trailing
--   data except for whitespace.
--   
--   This function parses and performs conversion immediately. See
--   json' for details.
decode' :: (FromJSON a) => ByteString -> Maybe a

-- | Like decode but returns an error message when decoding fails.
eitherDecode :: (FromJSON a) => ByteString -> Either String a

-- | Like decode' but returns an error message when decoding fails.
eitherDecode' :: (FromJSON a) => ByteString -> Either String a

-- | Efficiently serialize a JSON value as a lazy ByteString.
--   
--   This is implemented in terms of the ToJSON class's
--   toEncoding method.
encode :: (ToJSON a) => a -> ByteString

-- | Efficiently deserialize a JSON value from a strict ByteString.
--   If this fails due to incomplete or invalid input, Nothing is
--   returned.
--   
--   The input must consist solely of a JSON document, with no trailing
--   data except for whitespace.
--   
--   This function parses immediately, but defers conversion. See
--   json for details.
decodeStrict :: (FromJSON a) => ByteString -> Maybe a

-- | Efficiently deserialize a JSON value from a strict ByteString.
--   If this fails due to incomplete or invalid input, Nothing is
--   returned.
--   
--   The input must consist solely of a JSON document, with no trailing
--   data except for whitespace.
--   
--   This function parses and performs conversion immediately. See
--   json' for details.
decodeStrict' :: (FromJSON a) => ByteString -> Maybe a

-- | Like decodeStrict but returns an error message when decoding
--   fails.
eitherDecodeStrict :: (FromJSON a) => ByteString -> Either String a

-- | Like decodeStrict' but returns an error message when decoding
--   fails.
eitherDecodeStrict' :: (FromJSON a) => ByteString -> Either String a

-- | A JSON value represented as a Haskell value.
data Value
Object :: !Object -> Value
Array :: !Array -> Value
String :: !Text -> Value
Number :: !Scientific -> Value
Bool :: !Bool -> Value
Null :: Value

-- | Often used synonnym for Encoding'.
type Encoding = Encoding' Value

-- | Acquire the underlying bytestring builder.
fromEncoding :: Encoding' tag -> Builder

-- | A JSON "array" (sequence).
type Array = Vector Value

-- | A JSON "object" (key/value map).
type Object = HashMap Text Value

-- | A newtype wrapper for UTCTime that uses the same non-standard
--   serialization format as Microsoft .NET, whose System.DateTime
--   type is by default serialized to JSON as in the following example:
--   
--   
--   /Date(1302547608878)/
--   
--   
--   The number represents milliseconds since the Unix epoch.
newtype DotNetTime
DotNetTime :: UTCTime -> DotNetTime

-- | Acquire the underlying value.
[fromDotNetTime] :: DotNetTime -> UTCTime

-- | A type that can be converted from JSON, with the possibility of
--   failure.
--   
--   In many cases, you can get the compiler to generate parsing code for
--   you (see below). To begin, let's cover writing an instance by hand.
--   
--   There are various reasons a conversion could fail. For example, an
--   Object could be missing a required key, an Array could
--   be of the wrong size, or a value could be of an incompatible type.
--   
--   The basic ways to signal a failed conversion are as follows:
--   
--   
--   
- empty and mzero work, but are terse and
--   uninformative;
--   
- fail yields a custom error message;
--   
- typeMismatch produces an informative message for cases when
--   the value encountered is not of the expected type.
--   
--   
--   An example type and instance using typeMismatch:
--   
--   
--   -- Allow ourselves to write Text literals.
--   {-# LANGUAGE OverloadedStrings #-}
--   
--   data Coord = Coord { x :: Double, y :: Double }
--   
--   instance FromJSON Coord where
--       parseJSON (Object v) = Coord
--           <$> v .: "x"
--           <*> v .: "y"
--   
--       -- We do not expect a non-Object value here.
--       -- We could use mzero to fail, but typeMismatch
--       -- gives a much more informative error message.
--       parseJSON invalid    = typeMismatch "Coord" invalid
--   
--   
--   For this common case of only being concerned with a single type of
--   JSON value, the functions withObject, withNumber, etc.
--   are provided. Their use is to be preferred when possible, since they
--   are more terse. Using withObject, we can rewrite the above
--   instance (assuming the same language extension and data type) as:
--   
--   
--   instance FromJSON Coord where
--       parseJSON = withObject "Coord" $ v -> Coord
--           <$> v .: "x"
--           <*> v .: "y"
--   
--   
--   Instead of manually writing your FromJSON instance, there are
--   two options to do it automatically:
--   
--   
--   
- Data.Aeson.TH provides Template Haskell functions which
--   will derive an instance at compile time. The generated instance is
--   optimized for your type so it will probably be more efficient than the
--   following option.
--   
- The compiler can provide a default generic implementation for
--   parseJSON.
--   
--   
--   To use the second, simply add a deriving Generic
--   clause to your datatype and declare a FromJSON instance for
--   your datatype without giving a definition for parseJSON.
--   
--   For example, the previous example can be simplified to just:
--   
--   
--   {-# LANGUAGE DeriveGeneric #-}
--   
--   import GHC.Generics
--   
--   data Coord = Coord { x :: Double, y :: Double } deriving Generic
--   
--   instance FromJSON Coord
--   
--   
--   The default implementation will be equivalent to parseJSON =
--   genericParseJSON defaultOptions; If you need
--   different options, you can customize the generic decoding by defining:
--   
--   
--   customOptions = defaultOptions
--                   { fieldLabelModifier = map toUpper
--                   }
--   
--   instance FromJSON Coord where
--       parseJSON = genericParseJSON customOptions
--   
class FromJSON a where parseJSON = genericParseJSON defaultOptions parseJSONList (Array a) = zipWithM (parseIndexedJSON parseJSON) [0 .. ] . toList $ a parseJSONList v = typeMismatch "[a]" v
parseJSON :: FromJSON a => Value -> Parser a
parseJSON :: (FromJSON a, Generic a, GFromJSON Zero (Rep a)) => Value -> Parser a
parseJSONList :: FromJSON a => Value -> Parser [a]

-- | The result of running a Parser.
data Result a
Error :: String -> Result a
Success :: a -> Result a

-- | Convert a value from JSON, failing if the types do not match.
fromJSON :: (FromJSON a) => Value -> Result a

-- | A type that can be converted to JSON.
--   
--   Instances in general must specify toJSON and
--   should (but don't need to) specify toEncoding.
--   
--   An example type and instance:
--   
--   
--   -- Allow ourselves to write Text literals.
--   {-# LANGUAGE OverloadedStrings #-}
--   
--   data Coord = Coord { x :: Double, y :: Double }
--   
--   instance ToJSON Coord where
--     toJSON (Coord x y) = object ["x" .= x, "y" .= y]
--   
--     toEncoding (Coord x y) = pairs ("x" .= x <> "y" .= y)
--   
--   
--   Instead of manually writing your ToJSON instance, there are two
--   options to do it automatically:
--   
--   
--   
- Data.Aeson.TH provides Template Haskell functions which
--   will derive an instance at compile time. The generated instance is
--   optimized for your type so it will probably be more efficient than the
--   following option.
--   
- The compiler can provide a default generic implementation for
--   toJSON.
--   
--   
--   To use the second, simply add a deriving Generic
--   clause to your datatype and declare a ToJSON instance. If you
--   require nothing other than defaultOptions, it is sufficient to
--   write (and this is the only alternative where the default
--   toJSON implementation is sufficient):
--   
--   
--   {-# LANGUAGE DeriveGeneric #-}
--   
--   import GHC.Generics
--   
--   data Coord = Coord { x :: Double, y :: Double } deriving Generic
--   
--   instance ToJSON Coord where
--       toEncoding = genericToEncoding defaultOptions
--   
--   
--   If on the other hand you wish to customize the generic decoding, you
--   have to implement both methods:
--   
--   
--   customOptions = defaultOptions
--                   { fieldLabelModifier = map toUpper
--                   }
--   
--   instance ToJSON Coord where
--       toJSON     = genericToJSON customOptions
--       toEncoding = genericToEncoding customOptions
--   
--   
--   Previous versions of this library only had the toJSON method.
--   Adding toEncoding had to reasons:
--   
--   
--   
- toEncoding is more efficient for the common case that the output
--   of toJSON is directly serialized to a ByteString.
--   Further, expressing either method in terms of the other would be
--   non-optimal.
--   
- The choice of defaults allows a smooth transition for existing
--   users: Existing instances that do not define toEncoding still
--   compile and have the correct semantics. This is ensured by making the
--   default implementation of toEncoding use toJSON. This
--   produces correct results, but since it performs an intermediate
--   conversion to a Value, it will be less efficient than directly
--   emitting an Encoding. (this also means that specifying nothing
--   more than instance ToJSON Coord would be sufficient as a
--   generically decoding instance, but there probably exists no good
--   reason to not specify toEncoding in new instances.)
--   
class ToJSON a where toJSON = genericToJSON defaultOptions toEncoding = value . toJSON toJSONList = listValue toJSON toEncodingList = listEncoding toEncoding

-- | Convert a Haskell value to a JSON-friendly intermediate type.
toJSON :: ToJSON a => a -> Value

-- | Convert a Haskell value to a JSON-friendly intermediate type.
toJSON :: (ToJSON a, Generic a, GToJSON Zero (Rep a)) => a -> Value

-- | Encode a Haskell value as JSON.
--   
--   The default implementation of this method creates an intermediate
--   Value using toJSON. This provides source-level
--   compatibility for people upgrading from older versions of this
--   library, but obviously offers no performance advantage.
--   
--   To benefit from direct encoding, you must provide an
--   implementation for this method. The easiest way to do so is by having
--   your types implement Generic using the DeriveGeneric
--   extension, and then have GHC generate a method body as follows.
--   
--   
--   instance ToJSON Coord where
--       toEncoding = genericToEncoding defaultOptions
--   
toEncoding :: ToJSON a => a -> Encoding
toJSONList :: ToJSON a => [a] -> Value
toEncodingList :: ToJSON a => [a] -> Encoding

-- | A key-value pair for encoding a JSON object.
class KeyValue kv
(.=) :: (KeyValue kv, ToJSON v) => Text -> v -> kv

-- | Typeclass for types that can be used as the key of a map-like
--   container (like Map or HashMap). For example, since
--   Text has a ToJSONKey instance and Char has a
--   ToJSON instance, we can encode a value of type Map
--   Text Char:
--   
--   
--   >>> LBC8.putStrLn $ encode $ Map.fromList [("foo" :: Text, 'a')]
--   {"foo":"a"}
--   
--   
--   Since Int also has a ToJSONKey instance, we can
--   similarly write:
--   
--   
--   >>> LBC8.putStrLn $ encode $ Map.fromList [(5 :: Int, 'a')]
--   {"5":"a"}
--   
--   
--   JSON documents only accept strings as object keys. For any type from
--   base that has a natural textual representation, it can be
--   expected that its ToJSONKey instance will choose that
--   representation.
--   
--   For data types that lack a natural textual representation, an
--   alternative is provided. The map-like container is represented as a
--   JSON array instead of a JSON object. Each value in the array is an
--   array with exactly two values. The first is the key and the second is
--   the value.
--   
--   For example, values of type '[Text]' cannot be encoded to a string, so
--   a Map with keys of type '[Text]' is encoded as follows:
--   
--   
--   >>> LBC8.putStrLn $ encode $ Map.fromList [(["foo","bar","baz" :: Text], 'a')]
--   [[["foo","bar","baz"],"a"]]
--   
--   
--   The default implementation of ToJSONKey chooses this method of
--   encoding a key, using the ToJSON instance of the type.
--   
--   To use your own data type as the key in a map, all that is needed is
--   to write a ToJSONKey (and possibly a FromJSONKey)
--   instance for it. If the type cannot be trivially converted to and from
--   Text, it is recommended that ToJSONKeyValue is used.
--   Since the default implementations of the typeclass methods can build
--   this from a ToJSON instance, there is nothing that needs to be
--   written:
--   
--   
--   data Foo = Foo { fooAge :: Int, fooName :: Text }
--     deriving (Eq,Ord,Generic)
--   instance ToJSON Foo
--   instance ToJSONKey Foo
--   
--   
--   That's it. We can now write:
--   
--   
--   >>> let m = Map.fromList [(Foo 4 "bar",'a'),(Foo 6 "arg",'b')]
--   
--   >>> LBC8.putStrLn $ encode m
--   [[{"fooName":"bar","fooAge":4},"a"],[{"fooName":"arg","fooAge":6},"b"]]
--   
--   
--   The next case to consider is if we have a type that is a newtype
--   wrapper around Text. The recommended approach is to use
--   generalized newtype deriving:
--   
--   
--   newtype RecordId = RecordId { getRecordId :: Text}
--     deriving (Eq,Ord,ToJSONKey)
--   
--   
--   Then we may write:
--   
--   
--   >>> LBC8.putStrLn $ encode $ Map.fromList [(RecordId "abc",'a')]
--   {"abc":"a"}
--   
--   
--   Simple sum types are a final case worth considering. Suppose we have:
--   
--   
--   data Color = Red | Green | Blue
--     deriving (Show,Read,Eq,Ord)
--   
--   
--   It is possible to get the ToJSONKey instance for free as we did
--   with Foo. However, in this case, we have a natural way to go
--   to and from Text that does not require any escape sequences.
--   So, in this example, ToJSONKeyText will be used instead of
--   ToJSONKeyValue. The Show instance can be used to help
--   write ToJSONKey:
--   
--   
--   instance ToJSONKey Color where
--     toJSONKey = ToJSONKeyText f g
--       where f = Text.pack . show
--             g = text . Text.pack . show
--             -- text function is from Data.Aeson.Encoding
--   
--   
--   The situation of needing to turning function a -> Text
--   into a ToJSONKeyFunction is common enough that a special
--   combinator is provided for it. The above instance can be rewritten as:
--   
--   
--   instance ToJSONKey Color where
--     toJSONKey = toJSONKeyText (Text.pack . show)
--   
--   
--   The performance of the above instance can be improved by not using
--   String as an intermediate step when converting to Text.
--   One option for improving performance would be to use template haskell
--   machinery from the text-show package. However, even with the
--   approach, the Encoding (a wrapper around a bytestring builder)
--   is generated by encoding the Text to a ByteString, an
--   intermediate step that could be avoided. The fastest possible
--   implementation would be:
--   
--   
--   -- Assuming that OverloadedStrings is enabled
--   instance ToJSONKey Color where
--     toJSONKey = ToJSONKeyText f g
--       where f x = case x of {Red -> "Red";Green ->"Green";Blue -> "Blue"}
--             g x = case x of {Red -> text "Red";Green -> text "Green";Blue -> text "Blue"}
--             -- text function is from Data.Aeson.Encoding
--   
--   
--   This works because GHC can lift the encoded values out of the case
--   statements, which means that they are only evaluated once. This
--   approach should only be used when there is a serious need to maximize
--   performance.
class ToJSONKey a where toJSONKey = ToJSONKeyValue toJSON toEncoding toJSONKeyList = ToJSONKeyValue toJSON toEncoding

-- | Strategy for rendering the key for a map-like container.
toJSONKey :: ToJSONKey a => ToJSONKeyFunction a

-- | Strategy for rendering the key for a map-like container.
toJSONKey :: (ToJSONKey a, ToJSON a) => ToJSONKeyFunction a

-- | This is similar in spirit to the showsList method of
--   Show. It makes it possible to give String keys special
--   treatment without using OverlappingInstances. End users
--   should always be able to use the default implementation of this
--   method.
toJSONKeyList :: ToJSONKey a => ToJSONKeyFunction [a]

-- | This is similar in spirit to the showsList method of
--   Show. It makes it possible to give String keys special
--   treatment without using OverlappingInstances. End users
--   should always be able to use the default implementation of this
--   method.
toJSONKeyList :: (ToJSONKey a, ToJSON a) => ToJSONKeyFunction [a]
data ToJSONKeyFunction a

-- | key is encoded to string, produces object
ToJSONKeyText :: !(a -> Text) -> !(a -> Encoding' Text) -> ToJSONKeyFunction a

-- | key is encoded to value, produces array
ToJSONKeyValue :: !(a -> Value) -> !(a -> Encoding) -> ToJSONKeyFunction a

-- | Read the docs for ToJSONKey first. This class is a conversion
--   in the opposite direction. If you have a newtype wrapper around
--   Text, the recommended way to define instances is with
--   generalized newtype deriving:
--   
--   
--   newtype SomeId = SomeId { getSomeId :: Text }
--     deriving (Eq,Ord,Hashable,FromJSONKey)
--   
class FromJSONKey a where fromJSONKey = FromJSONKeyValue parseJSON fromJSONKeyList = FromJSONKeyValue parseJSON

-- | Strategy for parsing the key of a map-like container.
fromJSONKey :: FromJSONKey a => FromJSONKeyFunction a

-- | Strategy for parsing the key of a map-like container.
fromJSONKey :: (FromJSONKey a, FromJSON a) => FromJSONKeyFunction a

-- | This is similar in spirit to the readList method of
--   Read. It makes it possible to give String keys special
--   treatment without using OverlappingInstances. End users
--   should always be able to use the default implementation of this
--   method.
fromJSONKeyList :: FromJSONKey a => FromJSONKeyFunction [a]

-- | This is similar in spirit to the readList method of
--   Read. It makes it possible to give String keys special
--   treatment without using OverlappingInstances. End users
--   should always be able to use the default implementation of this
--   method.
fromJSONKeyList :: (FromJSONKey a, FromJSON a) => FromJSONKeyFunction [a]

-- | This type is related to ToJSONKeyFunction. If
--   FromJSONKeyValue is used in the FromJSONKey instance,
--   then ToJSONKeyValue should be used in the ToJSONKey
--   instance. The other three data constructors for this type all
--   correspond to ToJSONKeyText. Strictly speaking,
--   FromJSONKeyTextParser is more powerful than
--   FromJSONKeyText, which is in turn more powerful than
--   FromJSONKeyCoerce. For performance reasons, these exist as
--   three options instead of one.
data FromJSONKeyFunction a

-- | uses coerce (unsafeCoerce in older GHCs)
FromJSONKeyCoerce :: !(CoerceText a) -> FromJSONKeyFunction a

-- | conversion from Text that always succeeds
FromJSONKeyText :: !(Text -> a) -> FromJSONKeyFunction a

-- | conversion from Text that may fail
FromJSONKeyTextParser :: !(Text -> Parser a) -> FromJSONKeyFunction a

-- | conversion for non-textual keys
FromJSONKeyValue :: !(Value -> Parser a) -> FromJSONKeyFunction a

-- | Lifting of the FromJSON class to unary type constructors.
--   
--   Instead of manually writing your FromJSON1 instance, there are
--   two options to do it automatically:
--   
--   
--   
- Data.Aeson.TH provides Template Haskell functions which
--   will derive an instance at compile time. The generated instance is
--   optimized for your type so it will probably be more efficient than the
--   following option.
--   
- The compiler can provide a default generic implementation for
--   liftParseJSON.
--   
--   
--   To use the second, simply add a deriving Generic1
--   clause to your datatype and declare a FromJSON1 instance for
--   your datatype without giving a definition for liftParseJSON.
--   
--   For example:
--   
--   
--   {-# LANGUAGE DeriveGeneric #-}
--   
--   import GHC.Generics
--   
--   data Pair a b = Pair { pairFst :: a, pairSnd :: b } deriving Generic1
--   
--   instance FromJSON a => FromJSON1 (Pair a)
--   
--   
--   If the default implementation doesn't give exactly the results you
--   want, you can customize the generic decoding with only a tiny amount
--   of effort, using genericLiftParseJSON with your preferred
--   Options:
--   
--   
--   customOptions = defaultOptions
--                   { fieldLabelModifier = map toUpper
--                   }
--   
--   instance FromJSON a => FromJSON1 (Pair a) where
--       liftParseJSON = genericLiftParseJSON customOptions
--   
class FromJSON1 f where liftParseJSON = genericLiftParseJSON defaultOptions liftParseJSONList f g v = listParser (liftParseJSON f g) v
liftParseJSON :: FromJSON1 f => (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (f a)
liftParseJSON :: (FromJSON1 f, Generic1 f, GFromJSON One (Rep1 f)) => (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (f a)
liftParseJSONList :: FromJSON1 f => (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [f a]

-- | Lift the standard parseJSON function through the type
--   constructor.
parseJSON1 :: (FromJSON1 f, FromJSON a) => Value -> Parser (f a)

-- | Lifting of the FromJSON class to binary type constructors.
--   
--   Instead of manually writing your FromJSON2 instance,
--   Data.Aeson.TH provides Template Haskell functions which will
--   derive an instance at compile time.
class FromJSON2 f where liftParseJSONList2 fa ga fb gb v = case v of { Array vals -> fmap toList (mapM (liftParseJSON2 fa ga fb gb) vals) _ -> typeMismatch "[a]" v }
liftParseJSON2 :: FromJSON2 f => (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser (f a b)
liftParseJSONList2 :: FromJSON2 f => (Value -> Parser a) -> (Value -> Parser [a]) -> (Value -> Parser b) -> (Value -> Parser [b]) -> Value -> Parser [f a b]

-- | Lift the standard parseJSON function through the type
--   constructor.
parseJSON2 :: (FromJSON2 f, FromJSON a, FromJSON b) => Value -> Parser (f a b)

-- | Lifting of the ToJSON class to unary type constructors.
--   
--   Instead of manually writing your ToJSON1 instance, there are
--   two options to do it automatically:
--   
--   
--   
- Data.Aeson.TH provides Template Haskell functions which
--   will derive an instance at compile time. The generated instance is
--   optimized for your type so it will probably be more efficient than the
--   following option.
--   
- The compiler can provide a default generic implementation for
--   toJSON1.
--   
--   
--   To use the second, simply add a deriving Generic1
--   clause to your datatype and declare a ToJSON1 instance for your
--   datatype without giving definitions for liftToJSON or
--   liftToEncoding.
--   
--   For example:
--   
--   
--   {-# LANGUAGE DeriveGeneric #-}
--   
--   import GHC.Generics
--   
--   data Pair = Pair { pairFst :: a, pairSnd :: b } deriving Generic1
--   
--   instance ToJSON a => ToJSON1 (Pair a)
--   
--   
--   If the default implementation doesn't give exactly the results you
--   want, you can customize the generic encoding with only a tiny amount
--   of effort, using genericLiftToJSON and
--   genericLiftToEncoding with your preferred Options:
--   
--   
--   customOptions = defaultOptions
--                   { fieldLabelModifier = map toUpper
--                   }
--   
--   instance ToJSON a => ToJSON1 (Pair a) where
--       liftToJSON     = genericLiftToJSON customOptions
--       liftToEncoding = genericLiftToEncoding customOptions
--   
--   
--   See also ToJSON.
class ToJSON1 f where liftToJSON = genericLiftToJSON defaultOptions liftToJSONList f g = listValue (liftToJSON f g) liftToEncoding = genericLiftToEncoding defaultOptions liftToEncodingList f g = listEncoding (liftToEncoding f g)
liftToJSON :: ToJSON1 f => (a -> Value) -> ([a] -> Value) -> f a -> Value
liftToJSON :: (ToJSON1 f, Generic1 f, GToJSON One (Rep1 f)) => (a -> Value) -> ([a] -> Value) -> f a -> Value
liftToJSONList :: ToJSON1 f => (a -> Value) -> ([a] -> Value) -> [f a] -> Value
liftToEncoding :: ToJSON1 f => (a -> Encoding) -> ([a] -> Encoding) -> f a -> Encoding
liftToEncoding :: (ToJSON1 f, Generic1 f, GToEncoding One (Rep1 f)) => (a -> Encoding) -> ([a] -> Encoding) -> f a -> Encoding
liftToEncodingList :: ToJSON1 f => (a -> Encoding) -> ([a] -> Encoding) -> [f a] -> Encoding

-- | Lift the standard toJSON function through the type constructor.
toJSON1 :: (ToJSON1 f, ToJSON a) => f a -> Value

-- | Lift the standard toEncoding function through the type
--   constructor.
toEncoding1 :: (ToJSON1 f, ToJSON a) => f a -> Encoding

-- | Lifting of the ToJSON class to binary type constructors.
--   
--   Instead of manually writing your ToJSON2 instance,
--   Data.Aeson.TH provides Template Haskell functions which will
--   derive an instance at compile time.
--   
--   The compiler cannot provide a default generic implementation for
--   liftToJSON2, unlike toJSON and liftToJSON.
class ToJSON2 f where liftToJSONList2 fa ga fb gb = listValue (liftToJSON2 fa ga fb gb) liftToEncodingList2 fa ga fb gb = listEncoding (liftToEncoding2 fa ga fb gb)
liftToJSON2 :: ToJSON2 f => (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> f a b -> Value
liftToJSONList2 :: ToJSON2 f => (a -> Value) -> ([a] -> Value) -> (b -> Value) -> ([b] -> Value) -> [f a b] -> Value
liftToEncoding2 :: ToJSON2 f => (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> f a b -> Encoding
liftToEncodingList2 :: ToJSON2 f => (a -> Encoding) -> ([a] -> Encoding) -> (b -> Encoding) -> ([b] -> Encoding) -> [f a b] -> Encoding

-- | Lift the standard toJSON function through the type constructor.
toJSON2 :: (ToJSON2 f, ToJSON a, ToJSON b) => f a b -> Value

-- | Lift the standard toEncoding function through the type
--   constructor.
toEncoding2 :: (ToJSON2 f, ToJSON a, ToJSON b) => f a b -> Encoding

-- | Class of generic representation types that can be converted from JSON.
class GFromJSON arity f

-- | This method (applied to defaultOptions) is used as the default
--   generic implementation of parseJSON (if the arity is
--   Zero) or liftParseJSON (if the arity is
--   One).
gParseJSON :: GFromJSON arity f => Options -> FromArgs arity a -> Value -> Parser (f a)

-- | A FromArgs value either stores nothing (for FromJSON) or
--   it stores the two function arguments that decode occurrences of the
--   type parameter (for FromJSON1).
data FromArgs arity a
[NoFromArgs] :: FromArgs Zero a
[From1Args] :: (Value -> Parser a) -> (Value -> Parser [a]) -> FromArgs One a

-- | Class of generic representation types that can be converted to JSON.
class GToJSON arity f

-- | This method (applied to defaultOptions) is used as the default
--   generic implementation of toJSON (if the arity is
--   Zero) or liftToJSON (if the arity is
--   One).
gToJSON :: GToJSON arity f => Options -> ToArgs Value arity a -> f a -> Value

-- | Class of generic representation types that can be converted to a JSON
--   Encoding.
class GToEncoding arity f

-- | This method (applied to defaultOptions) can be used as the
--   default generic implementation of toEncoding (if the
--   arity is Zero) or liftToEncoding (if the
--   arity is One).
gToEncoding :: GToEncoding arity f => Options -> ToArgs Encoding arity a -> f a -> Encoding

-- | A ToArgs value either stores nothing (for ToJSON) or it
--   stores the two function arguments that encode occurrences of the type
--   parameter (for ToJSON1).
data ToArgs res arity a
[NoToArgs] :: ToArgs res Zero a
[To1Args] :: (a -> res) -> ([a] -> res) -> ToArgs res One a

-- | A type-level indicator that ToJSON or FromJSON is
--   being derived generically.
data Zero

-- | A type-level indicator that ToJSON1 or FromJSON1 is
--   being derived generically.
data One

-- | A configurable generic JSON creator. This function applied to
--   defaultOptions is used as the default for toJSON when
--   the type is an instance of Generic.
genericToJSON :: (Generic a, GToJSON Zero (Rep a)) => Options -> a -> Value

-- | A configurable generic JSON creator. This function applied to
--   defaultOptions is used as the default for liftToJSON
--   when the type is an instance of Generic1.
genericLiftToJSON :: (Generic1 f, GToJSON One (Rep1 f)) => Options -> (a -> Value) -> ([a] -> Value) -> f a -> Value

-- | A configurable generic JSON encoder. This function applied to
--   defaultOptions is used as the default for toEncoding
--   when the type is an instance of Generic.
genericToEncoding :: (Generic a, GToEncoding Zero (Rep a)) => Options -> a -> Encoding

-- | A configurable generic JSON encoder. This function applied to
--   defaultOptions is used as the default for liftToEncoding
--   when the type is an instance of Generic1.
genericLiftToEncoding :: (Generic1 f, GToEncoding One (Rep1 f)) => Options -> (a -> Encoding) -> ([a] -> Encoding) -> f a -> Encoding

-- | A configurable generic JSON decoder. This function applied to
--   defaultOptions is used as the default for parseJSON when
--   the type is an instance of Generic.
genericParseJSON :: (Generic a, GFromJSON Zero (Rep a)) => Options -> Value -> Parser a

-- | A configurable generic JSON decoder. This function applied to
--   defaultOptions is used as the default for liftParseJSON
--   when the type is an instance of Generic1.
genericLiftParseJSON :: (Generic1 f, GFromJSON One (Rep1 f)) => Options -> (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (f a)

-- | Default encoding Options:
--   
--   
--   Options
--   { fieldLabelModifier      = id
--   , constructorTagModifier  = id
--   , allNullaryToStringTag   = True
--   , omitNothingFields       = False
--   , sumEncoding             = defaultTaggedObject
--   , unwrapUnaryRecords      = False
--   }
--   
defaultOptions :: Options

-- | withObject expected f value applies f to the
--   Object when value is an Object and fails using
--   typeMismatch expected otherwise.
withObject :: String -> (Object -> Parser a) -> Value -> Parser a

-- | withText expected f value applies f to the
--   Text when value is a String and fails using
--   typeMismatch expected otherwise.
withText :: String -> (Text -> Parser a) -> Value -> Parser a

-- | withArray expected f value applies f to the
--   Array when value is an Array and fails using
--   typeMismatch expected otherwise.
withArray :: String -> (Array -> Parser a) -> Value -> Parser a

-- | withNumber expected f value applies f to the
--   Number when value is a Number and fails using
--   typeMismatch expected otherwise.

-- | Deprecated: Use withScientific instead
withNumber :: String -> (Number -> Parser a) -> Value -> Parser a

-- | withScientific expected f value applies f to
--   the Scientific number when value is a Number
--   and fails using typeMismatch expected otherwise.
withScientific :: String -> (Scientific -> Parser a) -> Value -> Parser a

-- | withBool expected f value applies f to the
--   Bool when value is a Bool and fails using
--   typeMismatch expected otherwise.
withBool :: String -> (Bool -> Parser a) -> Value -> Parser a

-- | A series of values that, when encoded, should be separated by commas.
--   Since 0.11.0.0, the .= operator is overloaded to create
--   either (Text, Value) or Series. You can use Series
--   when encoding directly to a bytestring builder as in the following
--   example:
--   
--   
--   toEncoding (Person name age) = pairs ("name" .= name <> "age" .= age)
--   
data Series

-- | Encode a series of key/value pairs, separated by commas.
pairs :: Series -> Encoding

-- | Encode a Foldable as a JSON array.
foldable :: (Foldable t, ToJSON a) => t a -> Encoding

-- | Retrieve the value associated with the given key of an Object.
--   The result is empty if the key is not present or the value
--   cannot be converted to the desired type.
--   
--   This accessor is appropriate if the key and value must be
--   present in an object for it to be valid. If the key and value are
--   optional, use .:? instead.
(.:) :: (FromJSON a) => Object -> Text -> Parser a

-- | Retrieve the value associated with the given key of an Object.
--   The result is Nothing if the key is not present or if its value
--   is Null, or empty if the value cannot be converted to
--   the desired type.
--   
--   This accessor is most useful if the key and value can be absent from
--   an object without affecting its validity. If the key and value are
--   mandatory, use .: instead.
(.:?) :: (FromJSON a) => Object -> Text -> Parser (Maybe a)

-- | Retrieve the value associated with the given key of an Object.
--   The result is Nothing if the key is not present or
--   empty if the value cannot be converted to the desired type.
--   
--   This differs from .:? by attempting to parse Null the
--   same as any other JSON value, instead of interpreting it as
--   Nothing.
(.:!) :: (FromJSON a) => Object -> Text -> Parser (Maybe a)

-- | Helper for use in combination with .:? to provide default
--   values for optional JSON object fields.
--   
--   This combinator is most useful if the key and value can be absent from
--   an object without affecting its validity and we know a default value
--   to assign in that case. If the key and value are mandatory, use
--   .: instead.
--   
--   Example usage:
--   
--   
--   v1 <- o .:? "opt_field_with_dfl" .!= "default_val"
--   v2 <- o .:  "mandatory_field"
--   v3 <- o .:? "opt_field2"
--   
(.!=) :: Parser (Maybe a) -> a -> Parser a

-- | Create a Value from a list of name/value Pairs. If
--   duplicate keys arise, earlier keys and their associated values win.
object :: [Pair] -> Value

-- | Parse a top-level JSON value.
--   
--   The conversion of a parsed value to a Haskell value is deferred until
--   the Haskell value is needed. This may improve performance if only a
--   subset of the results of conversions are needed, but at a cost in
--   thunk allocation.
--   
--   This function is an alias for value. In aeson 0.8 and earlier,
--   it parsed only object or array types, in conformance with the
--   now-obsolete RFC 4627.
json :: Parser Value

-- | Parse a top-level JSON value.
--   
--   This is a strict version of json which avoids building up
--   thunks during parsing; it performs all conversions immediately. Prefer
--   this version if most of the JSON data needs to be accessed.
--   
--   This function is an alias for value'. In aeson 0.8 and earlier,
--   it parsed only object or array types, in conformance with the
--   now-obsolete RFC 4627.
json' :: Parser Value

-- | This module is left to supply limited backwards-compatibility.

-- | Deprecated: Use Data.Aeson or Data.Aeson.Text instead
module Data.Aeson.Encode
encode :: ToJSON a => a -> ByteString
encodeToTextBuilder :: Value -> Builder

-- | Functions to mechanically derive ToJSON and FromJSON
--   instances. Note that you need to enable the TemplateHaskell
--   language extension in order to use this module.
--   
--   An example shows how instances are generated for arbitrary data types.
--   First we define a data type:
--   
--   
--   data D a = Nullary
--            | Unary Int
--            | Product String Char a
--            | Record { testOne   :: Double
--                     , testTwo   :: Bool
--                     , testThree :: D a
--                     } deriving Eq
--   
--   
--   Next we derive the necessary instances. Note that we make use of the
--   feature to change record field names. In this case we drop the first 4
--   characters of every field name. We also modify constructor names by
--   lower-casing them:
--   
--   
--   $(deriveJSON defaultOptions{fieldLabelModifier = drop 4, constructorTagModifier = map toLower} ''D)
--   
--   
--   Now we can use the newly created instances.
--   
--   
--   d :: D Int
--   d = Record { testOne = 3.14159
--              , testTwo = True
--              , testThree = Product "test" 'A' 123
--              }
--   
--   
--   
--   >>> fromJSON (toJSON d) == Success d
--   > True
--   
--   
--   This also works for data family instances, but instead of passing in
--   the data family name (with double quotes), we pass in a data family
--   instance constructor (with a single quote):
--   
--   
--   data family DF a
--   data instance DF Int = DF1 Int
--                        | DF2 Int Int
--                        deriving Eq
--   
--   $(deriveJSON defaultOptions 'DF1)
--   -- Alternatively, one could pass 'DF2 instead
--   
--   
--   Please note that you can derive instances for tuples using the
--   following syntax:
--   
--   
--   -- FromJSON and ToJSON instances for 4-tuples.
--   $(deriveJSON defaultOptions ''(,,,))
--   
module Data.Aeson.TH

-- | Options that specify how to encode/decode your datatype to/from JSON.
data Options
Options :: (String -> String) -> (String -> String) -> Bool -> Bool -> SumEncoding -> Bool -> Options

-- | Function applied to field labels. Handy for removing common record
--   prefixes for example.
[fieldLabelModifier] :: Options -> String -> String

-- | Function applied to constructor tags which could be handy for
--   lower-casing them for example.
[constructorTagModifier] :: Options -> String -> String

-- | If True the constructors of a datatype, with all nullary
--   constructors, will be encoded to just a string with the constructor
--   tag. If False the encoding will always follow the
--   sumEncoding.
[allNullaryToStringTag] :: Options -> Bool

-- | If True record fields with a Nothing value will be
--   omitted from the resulting object. If False the resulting
--   object will include those fields mapping to null.
[omitNothingFields] :: Options -> Bool

-- | Specifies how to encode constructors of a sum datatype.
[sumEncoding] :: Options -> SumEncoding

-- | Hide the field name when a record constructor has only one field, like
--   a newtype.
[unwrapUnaryRecords] :: Options -> Bool

-- | Specifies how to encode constructors of a sum datatype.
data SumEncoding

-- | A constructor will be encoded to an object with a field
--   tagFieldName which specifies the constructor tag (modified by
--   the constructorTagModifier). If the constructor is a record the
--   encoded record fields will be unpacked into this object. So make sure
--   that your record doesn't have a field with the same label as the
--   tagFieldName. Otherwise the tag gets overwritten by the encoded
--   value of that field! If the constructor is not a record the encoded
--   constructor contents will be stored under the contentsFieldName
--   field.
TaggedObject :: String -> String -> SumEncoding
[tagFieldName] :: SumEncoding -> String
[contentsFieldName] :: SumEncoding -> String

-- | Constructor names won't be encoded. Instead only the contents of the
--   constructor will be encoded as if the type had a single constructor.
--   JSON encodings have to be disjoint for decoding to work properly.
--   
--   When decoding, constructors are tried in the order of definition. If
--   some encodings overlap, the first one defined will succeed.
--   
--   Note: Nullary constructors are encoded as strings (using
--   constructorTagModifier). Having a nullary constructor alongside
--   a single field constructor that encodes to a string leads to
--   ambiguity.
--   
--   Note: Only the last error is kept when decoding, so in the case
--   of malformed JSON, only an error for the last constructor will be
--   reported.
UntaggedValue :: SumEncoding

-- | A constructor will be encoded to an object with a single field named
--   after the constructor tag (modified by the
--   constructorTagModifier) which maps to the encoded contents of
--   the constructor.
ObjectWithSingleField :: SumEncoding

-- | A constructor will be encoded to a 2-element array where the first
--   element is the tag of the constructor (modified by the
--   constructorTagModifier) and the second element the encoded
--   contents of the constructor.
TwoElemArray :: SumEncoding

-- | Default encoding Options:
--   
--   
--   Options
--   { fieldLabelModifier      = id
--   , constructorTagModifier  = id
--   , allNullaryToStringTag   = True
--   , omitNothingFields       = False
--   , sumEncoding             = defaultTaggedObject
--   , unwrapUnaryRecords      = False
--   }
--   
defaultOptions :: Options

-- | Default TaggedObject SumEncoding options:
--   
--   
--   defaultTaggedObject = TaggedObject
--                         { tagFieldName      = "tag"
--                         , contentsFieldName = "contents"
--                         }
--   
defaultTaggedObject :: SumEncoding

-- | Generates both ToJSON and FromJSON instance declarations
--   for the given data type or data family instance constructor.
--   
--   This is a convienience function which is equivalent to calling both
--   deriveToJSON and deriveFromJSON.
deriveJSON :: Options -> Name -> Q [Dec]

-- | Generates both ToJSON1 and FromJSON1 instance
--   declarations for the given data type or data family instance
--   constructor.
--   
--   This is a convienience function which is equivalent to calling both
--   deriveToJSON1 and deriveFromJSON1.
deriveJSON1 :: Options -> Name -> Q [Dec]

-- | Generates both ToJSON2 and FromJSON2 instance
--   declarations for the given data type or data family instance
--   constructor.
--   
--   This is a convienience function which is equivalent to calling both
--   deriveToJSON2 and deriveFromJSON2.
deriveJSON2 :: Options -> Name -> Q [Dec]

-- | Generates a ToJSON instance declaration for the given data type
--   or data family instance constructor.
deriveToJSON :: Options -> Name -> Q [Dec]

-- | Generates a ToJSON1 instance declaration for the given data
--   type or data family instance constructor.
deriveToJSON1 :: Options -> Name -> Q [Dec]

-- | Generates a ToJSON2 instance declaration for the given data
--   type or data family instance constructor.
deriveToJSON2 :: Options -> Name -> Q [Dec]

-- | Generates a FromJSON instance declaration for the given data
--   type or data family instance constructor.
deriveFromJSON :: Options -> Name -> Q [Dec]

-- | Generates a FromJSON1 instance declaration for the given data
--   type or data family instance constructor.
deriveFromJSON1 :: Options -> Name -> Q [Dec]

-- | Generates a FromJSON2 instance declaration for the given data
--   type or data family instance constructor.
deriveFromJSON2 :: Options -> Name -> Q [Dec]

-- | Generates a lambda expression which encodes the given data type or
--   data family instance constructor as a Value.
mkToJSON :: Options -> Name -> Q Exp

-- | Generates a lambda expression which encodes the given data type or
--   data family instance constructor as a Value by using the given
--   encoding function on occurrences of the last type parameter.
mkLiftToJSON :: Options -> Name -> Q Exp

-- | Generates a lambda expression which encodes the given data type or
--   data family instance constructor as a Value by using the given
--   encoding functions on occurrences of the last two type parameters.
mkLiftToJSON2 :: Options -> Name -> Q Exp

-- | Generates a lambda expression which encodes the given data type or
--   data family instance constructor as a JSON string.
mkToEncoding :: Options -> Name -> Q Exp

-- | Generates a lambda expression which encodes the given data type or
--   data family instance constructor as a JSON string by using the given
--   encoding function on occurrences of the last type parameter.
mkLiftToEncoding :: Options -> Name -> Q Exp

-- | Generates a lambda expression which encodes the given data type or
--   data family instance constructor as a JSON string by using the given
--   encoding functions on occurrences of the last two type parameters.
mkLiftToEncoding2 :: Options -> Name -> Q Exp

-- | Generates a lambda expression which parses the JSON encoding of the
--   given data type or data family instance constructor.
mkParseJSON :: Options -> Name -> Q Exp

-- | Generates a lambda expression which parses the JSON encoding of the
--   given data type or data family instance constructor by using the given
--   parsing function on occurrences of the last type parameter.
mkLiftParseJSON :: Options -> Name -> Q Exp

-- | Generates a lambda expression which parses the JSON encoding of the
--   given data type or data family instance constructor by using the given
--   parsing functions on occurrences of the last two type parameters.
mkLiftParseJSON2 :: Options -> Name -> Q Exp
instance GHC.Classes.Eq Data.Aeson.TH.StarKindStatus
instance GHC.Classes.Ord Data.Aeson.TH.Arity
instance GHC.Classes.Eq Data.Aeson.TH.Arity
instance GHC.Enum.Enum Data.Aeson.TH.Arity
instance Data.Aeson.TH.LookupField a
instance Data.Aeson.TH.LookupField (GHC.Base.Maybe a)
