Data.Registry.Aeson.Decoder

Documentation

type FieldDef = (Text, Text)

Field name + field type

newtype ConstructorsDecoder

This function extracts values for a set of constructor definitions The TemplateHaskell function makeDecoder can then use the constructor name and constructor field value to create an actual constructor instance for a given data type

Constructors

ConstructorsDecoder

Fields

• decodeConstructors :: Options -> [ConstructorDef] -> Value -> Either Text [ToConstructor]

data ToConstructor

Data parsed from a given Value to be potentially used to create a constructor instance of a type

Constructors

ToConstructor

Fields

• toConstructorName :: Text

  Name of the constructor to use (without modification)

• toConstructorValues :: [(Maybe FieldDef, Value)]

  Name of the values to decode for each field of the constructor instance

Instances

Show ToConstructor

Defined in Data.Registry.Aeson.Decoder

Methods

showsPrec :: Int -> ToConstructor -> ShowS

show :: ToConstructor -> String

showList :: [ToConstructor] -> ShowS

Eq ToConstructor

Defined in Data.Registry.Aeson.Decoder

Methods

(==) :: ToConstructor -> ToConstructor -> Bool

(/=) :: ToConstructor -> ToConstructor -> Bool

data ConstructorDef

Metadata for a given constructor in a data type

Constructors

ConstructorDef

Fields

• constructorDefName :: Text

  Name of the constructor

• constructorDefModifiedName :: Text

  Name of the constructor after modification with options

• constructorDefFields :: [Text]

  Name of the constructor fields (if any are defined with names. An empty list otherwise)

• constructorDefModifiedFieldNames :: [Text]

  Names of the fields after modification with options

• constructorDefFieldsTypes :: [Text]

  Types of the constructor fields

Instances

Show ConstructorDef

Defined in Data.Registry.Aeson.Decoder

Methods

showsPrec :: Int -> ConstructorDef -> ShowS

show :: ConstructorDef -> String

showList :: [ConstructorDef] -> ShowS

Eq ConstructorDef

Defined in Data.Registry.Aeson.Decoder

Methods

(==) :: ConstructorDef -> ConstructorDef -> Bool

(/=) :: ConstructorDef -> ConstructorDef -> Bool

newtype KeyDecoder a

Constructors

KeyDecoder

Fields

• decodeKeyAs :: Key -> Either Text a

Instances

Functor KeyDecoder

Defined in Data.Registry.Aeson.Decoder

Methods

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

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

newtype Decoder a

Constructors

Decoder

Fields

• decodeValue :: Value -> Either Text a

Instances

Applicative Decoder

Defined in Data.Registry.Aeson.Decoder

Methods

pure :: a -> Decoder a

(<*>) :: Decoder (a -> b) -> Decoder a -> Decoder b

liftA2 :: (a -> b -> c) -> Decoder a -> Decoder b -> Decoder c

(*>) :: Decoder a -> Decoder b -> Decoder b

(<*) :: Decoder a -> Decoder b -> Decoder a

Functor Decoder

Defined in Data.Registry.Aeson.Decoder

Methods

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

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

decoderAp :: Decoder a -> Decoder b -> Decoder (a, b)

decodeByteString :: forall a. Typeable a => Decoder a -> ByteString -> Either Text a

Use a Decoder to decode a ByteString into the desired type

decodeKey :: forall a. Typeable a => (Text -> Either Text a) -> Typed (KeyDecoder a)

Create a decoder for a key which can be read from text

keyDecoder :: forall a. (Text -> Either Text a) -> KeyDecoder a

jsonDecoder :: forall a. (FromJSON a, Typeable a) => Typed (Decoder a)

Add a Decoder a to a registry of decoders when a Aeson a instance exists usage: decoders = jsonDecoder @a <: otherDecoders

jsonDecoderOf :: FromJSON a => Decoder a

decodeMaybeOf :: forall a. Typeable a => Typed (Decoder a -> Decoder (Maybe a))

Add a Maybe (Decoder a) to a registry of decoders usage: decoders = decodeMaybeOf @a <: otherDecoders the list of otherDecoders must contain a Decoder a otherwise there will be a compilation error

maybeOfDecoder :: forall a. Decoder a -> Decoder (Maybe a)

decodePairOf :: forall a b. (Typeable a, Typeable b) => Typed (Decoder a -> Decoder b -> Decoder (a, b))

Add a Maybe (a, b) to a registry of decoders usage: decoders = decodePairOf a b <: otherDecoders the list of otherDecoders must contain a Decoder a and a Decoder b otherwise there will be a compilation error

pairOfDecoder :: forall a b. (Typeable a, Typeable b) => Decoder a -> Decoder b -> Decoder (a, b)

decodeTripleOf :: forall a b c. (Typeable a, Typeable b, Typeable c) => Typed (Decoder a -> Decoder b -> Decoder c -> Decoder (a, b, c))

Add a Maybe (a, b, c) to a registry of decoders usage: decoders = decodeTripleOf a b @c <: otherDecoders the list of otherDecoders must contain a Decoder a, a Decoder b and a Decoder c otherwise there will be a compilation error

tripleOfDecoder :: forall a b c. (Typeable a, Typeable b, Typeable c) => Decoder a -> Decoder b -> Decoder c -> Decoder (a, b, c)

decodeListOf :: forall a. Typeable a => Typed (Decoder a -> Decoder [a])

Add a Decoder [a] to a registry of decoders usage: decoders = decodeListOf @a <: otherDecoders the list of otherDecoders must contain a Decoder a otherwise there will be a compilation error

listOfDecoder :: forall a. Typeable a => Decoder a -> Decoder [a]

decodeMapOf :: forall a b. (Typeable a, Ord a, Typeable b) => Typed (KeyDecoder a -> Decoder b -> Decoder (Map a b))

mapOfDecoder :: forall a b. (Typeable a, Ord a, Typeable b) => KeyDecoder a -> Decoder b -> Decoder (Map a b)

decodeNonEmptyOf :: forall a. Typeable a => Typed (Decoder a -> Decoder (NonEmpty a))

Add a Decoder (NonEmpty a) to a registry of decoders usage: decoders = decodeNonEmptyOf @a <: otherDecoders the list of otherDecoders must contain a Decoder a otherwise there will be a compilation error

nonEmptyOfDecoder :: forall a. Typeable a => Decoder a -> Decoder (NonEmpty a)

showType :: forall a. Typeable a => String

defaultDecoderOptions :: Registry _ _

textKeyDecoder :: KeyDecoder Text

stringKeyDecoder :: KeyDecoder String

decodeFieldValue :: Decoder a -> Text -> Text -> (Maybe FieldDef, Value) -> Either Text a

Use a decoder to decode a field The constructor name, the type where the field is inserted and the field definition are used to provide better error messages

makeConstructorDef :: Text -> [Text] -> [Text] -> ConstructorDef

decodeFromDefinitions :: Options -> ConstructorsDecoder -> [ConstructorDef] -> Value -> (ToConstructor -> Either Text a) -> Either Text a

Try to find the appropriate constructor definition encoded in the json value then try to decode all its fields with decoding function

defaultConstructorsDecoder :: ConstructorsDecoder

makeToConstructors :: Options -> [ConstructorDef] -> Value -> Either Text [ToConstructor]

Try to extract possible constructor values based on: - the encoding options - the list of constructor definitions - a JSON value Several alternatives can be returned for an Untagged sum encoding when there are several constructor definitions

makeTaggedObject :: Options -> Text -> Text -> [ConstructorDef] -> Value -> Either Text ToConstructor

Try to find which constructor was encoded in a tagged object where the tag field encode the constructor name and the values are either inline in the object or in a contents field

makeUntaggedValue :: Options -> [ConstructorDef] -> Value -> Either Text [ToConstructor]

Try to find which constructor was encoded in an untagged value and extract its possible values

makeObjectWithSingleField :: Options -> [ConstructorDef] -> Value -> Either Text ToConstructor

Try to find which constructor was encoded in an object with a single field where the field name encodes the constructor name and the object values encode the constructor fields

makeTwoElemArray :: Options -> [ConstructorDef] -> Value -> Either Text ToConstructor

Try to find which constructor was encoded in an array with 2 elements where the first element encodes the constructor name and the other element the constructor values

checkSumEncoding :: Options -> [ConstructorDef] -> Value -> Maybe Text

Check if the sum encoding structure looks correct This requires the whole list of constructor definitions

applyOptions :: Options -> ConstructorDef -> ConstructorDef

Apply at runtime options to a constructor definition in order to be able to match field definitions in the decoded json value

makeToConstructorFromValue :: Options -> ConstructorDef -> Value -> Either Text ToConstructor

For a given constructor definition extract all the required fields from a json value

jsonTypeOf :: Value -> Text

Return a textual description of a json value

tryConstructors :: [ConstructorDef] -> (ConstructorDef -> Either Text ToConstructor) -> Either Text ToConstructor

Try to extract a constructor and its values from a list of constructor definitions

foldEither :: [Either Text c] -> Either Text c

Return the first right element if available

encodeAsText :: ToJSON a => a -> Text

Encode a value as Text using its ToJSON instance

plural :: Foldable f => f a -> Text

Return a "s" if there are more than one element

module Data.Registry.Aeson.TH.Decoder

module Data.Registry.Aeson.TH.ThOptions