Data.Json.Parser

Parsing from different types

parseJsonBs :: JsonReadable t => ByteString -> Either String t

Parse json from a strict ByteString

parseJsonBsl :: JsonReadable t => ByteString -> Either String t

Parse json from a lazy ByteString

parseJsonT :: JsonReadable t => Text -> Either String t

Parse json from a strict Text

Description how to parse JSON to a Haskell type

class JsonReadable t where

Typeclass defining an attoparsec Parser how Haskell types should be parsed from JSON. Use predifined instances (with readJson) and runSpec (on ObjSpec) to define instances for custom types

Methods

readJson :: Parser t

Instances

JsonReadable Bool

JsonReadable Double

JsonReadable Int

JsonReadable Int8

JsonReadable Int16

JsonReadable Int32

JsonReadable Int64

JsonReadable Word

JsonReadable Word8

JsonReadable Word16

JsonReadable Word32

JsonReadable Word64

JsonReadable Text

JsonReadable Scientific

JsonReadable t => JsonReadable [t]

JsonReadable t => JsonReadable (Maybe t)

JsonReadable t => JsonReadable (Vector t)

JsonReadable a => JsonReadable (HVect ((:) * a ([] *)))

(JsonReadable a, JsonReadable b) => JsonReadable (Either a b)

JsonReadable t => JsonReadable (t, t)

DSL to easily create parser for custom Haskell types

runParseSpec :: ParseSpec k -> Parser k

Convert a ParseSpec into a Parser

data ObjSpec ts where

List of TypedKeys, should be in the same order as your constructor in runSpec will expect them

Constructors

ObjSpecNil :: ObjSpec []

(:&&:) :: (JsonReadable t, Typeable t) => !(TypedKey t) -> !(ObjSpec ts) -> ObjSpec (t : ts) infixr 5

data ParseSpec k where

Parser specification. Use :$: for normal types and FirstConstr / :|: for sum types

Constructors

(:$:) :: HVectElim ts k -> ObjSpec ts -> ParseSpec k infixr 4

FirstConstr :: KeyedConstr k -> ParseSpec k

(:|:) :: KeyedConstr k -> ParseSpec k -> ParseSpec k

Instances

ConstrTagger (ParseSpec k)

type ResultType (ParseSpec k) = k

data KeyedConstr k

Associates a json key with a parser

Instances

ConstrTagger (KeyedConstr k)

type ResultType (KeyedConstr k) = k

(<||>) :: KeyedConstr k -> ParseSpec k -> ParseSpec k infixr 3

Choice between multiple constructors

class ConstrTagger r where

Associated Types

type ResultType r :: *

Methods

(.->) :: Text -> Parser (ResultType r) -> r

Associate a json key with a parser

Instances

ConstrTagger (ParseSpec k)

ConstrTagger (KeyedConstr k)

data TypedKey t

Json object key to a value t

Instances

Typeable * t => IsString (TypedKey t)

Typeable * t => IsString (TypedKey (Maybe t))

reqKey :: Typeable t => Text -> TypedKey t

Required json object key. Use IsString instance for automatic choice

optKey :: Typeable t => Text -> TypedKey (Maybe t)

Optional json object key. Use IsString instance for automatic choice

typedKeyKey :: TypedKey t -> Text

Get the textual key of a TypedKey

Low level JSON parsing helpers

readObject :: (Text -> Maybe (Parser a)) -> Parser (HashMap Text a)

Parse a json object given a value parser for each key

type Parser = Parser ByteString

data WrappedValue

A value that is Typeable and JsonReadable

Constructors

forall t . (Typeable t, JsonReadable t) => WrappedValue !t

getValueByKey :: (Monad m, Typeable t) => Text -> HashMap Text WrappedValue -> m t

Get a value out of the map returned by readObject

getOptValueByKey :: (Monad m, Typeable t) => Text -> HashMap Text WrappedValue -> m (Maybe t)

Optionally get a value out of the map returned by readObject