Copyright	(c) Dong Han 2019
License	BSD
Maintainer	winterland1989@gmail.com
Stability	experimental
Portability	non-portable
Safe Haskell	None
Language	Haskell2010

Z.Data.JSON.Value

Contents

Value type
parse into JSON Value
Value Parsers
Convert to Scientific

Description

This module provides definition and parsers for JSON Values, a Haskell JSON representation. The parsers is designed to comply with rfc8258, notable pitfalls are:

The numeric representation use Scientific, which impose a limit on number's exponent part(limited to Int).
Unescaped control characters(<=0x1F) are NOT accepted, (different from aeson).
Only 0x20, 0x09, 0x0A, 0x0D are valid JSON whitespaces, skipSpaces from this module is different from skipSpaces.
A JSON document shouldn't have trailing characters except whitespaces describe above, see parseValue'.
Objects are represented as key-value vectors, key order and duplicated keys are preserved for further processing.

Note that rfc8258 doesn't enforce unique key in objects, it's up to users to decided how to deal with key duplication, e.g. prefer first or last key, see withFlatMap or withFlatMapR for example.

There's no lazy parsers here, every pieces of JSON document will be parsed into a normal form Value. Object and Arrays payloads are packed into Vectors to avoid accumulating lists in memory. Read more about why no lazy parsing is needed.

Synopsis

data Value
- = Object !(Vector (Text, Value))
- | Array !(Vector Value)
- | String !Text
- | Number !Scientific
- | Bool !Bool
- | Null
key :: Functor f => Text -> (Value -> f Value) -> Value -> f Value
nth :: Functor f => Int -> (Value -> f Value) -> Value -> f Value
parseValue :: Bytes -> (Bytes, Either ParseError Value)
parseValue' :: Bytes -> Either ParseError Value
value :: Parser Value
object :: Parser (Vector (Text, Value))
array :: Parser (Vector Value)
string :: Parser Text
skipSpaces :: Parser ()
floatToScientific :: Float -> Scientific
doubleToScientific :: Double -> Scientific

Value type

data Value Source #

A JSON value represented as a Haskell value.

The Object's payload is a key-value vector instead of a map, which parsed directly from JSON document. This design choice has following advantages:

Allow different strategies handling duplicated keys.
Allow different Map type to do further parsing, e.g. FlatMap
Roundtrip without touching the original key-value order.
Save time if constructing map is not neccessary, e.g. using a linear scan to find a key if only that key is needed.

Constructors

Object !(Vector (Text, Value))
Array !(Vector Value)
String !Text
Number !Scientific
Bool !Bool
Null

Instances

Instances details

Eq Value Source #
Instance details Defined in Z.Data.JSON.Value Methods (==) :: Value -> Value -> Bool # (/=) :: Value -> Value -> Bool #
Ord Value Source #
Instance details Defined in Z.Data.JSON.Value Methods compare :: Value -> Value -> Ordering # (<) :: Value -> Value -> Bool # (<=) :: Value -> Value -> Bool # (>) :: Value -> Value -> Bool # (>=) :: Value -> Value -> Bool # max :: Value -> Value -> Value # min :: Value -> Value -> Value #
Show Value Source #
Instance details Defined in Z.Data.JSON.Value Methods showsPrec :: Int -> Value -> ShowS # show :: Value -> String # showList :: [Value] -> ShowS #
Generic Value Source #
Instance details Defined in Z.Data.JSON.Value Associated Types type Rep Value :: Type -> Type # Methods from :: Value -> Rep Value x # to :: Rep Value x -> Value #
Arbitrary Value Source #
Instance details Defined in Z.Data.JSON.Value Methods arbitrary :: Gen Value # shrink :: Value -> [Value] #
NFData Value Source #
Instance details Defined in Z.Data.JSON.Value Methods rnf :: Value -> () #
Print Value Source #
Instance details Defined in Z.Data.JSON.Value Methods toUTF8BuilderP :: Int -> Value -> Builder () Source #
JSON Value Source #
Instance details Defined in Z.Data.JSON.Base Methods fromValue :: Value -> Converter Value Source # toValue :: Value -> Value Source # encodeJSON :: Value -> Builder () Source #
type Rep Value Source #
Instance details Defined in Z.Data.JSON.Value type Rep Value = D1 ('MetaData "Value" "Z.Data.JSON.Value" "Z-Data-0.8.3.0-37u7OlWXbeeLJtWSrSJkMP" 'False) ((C1 ('MetaCons "Object" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'SourceUnpack 'SourceStrict 'DecidedStrict) (Rec0 (Vector (Text, Value)))) :+: (C1 ('MetaCons "Array" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'SourceUnpack 'SourceStrict 'DecidedStrict) (Rec0 (Vector Value))) :+: C1 ('MetaCons "String" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'SourceUnpack 'SourceStrict 'DecidedStrict) (Rec0 Text)))) :+: (C1 ('MetaCons "Number" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'SourceUnpack 'SourceStrict 'DecidedStrict) (Rec0 Scientific)) :+: (C1 ('MetaCons "Bool" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 Bool)) :+: C1 ('MetaCons "Null" 'PrefixI 'False) (U1 :: Type -> Type))))