| Safe Haskell | None |
|---|---|
| Language | Haskell2010 |
Data.Aeson.Deriving.Generic
Contents
Synopsis
- class ToAesonOptions a where
- toAesonOptions :: Proxy a -> Options
- newtype GenericEncoded opts a = GenericEncoded a
- newtype RecordSumEncoded (tagKey :: Symbol) (tagModifier :: k) (a :: Type) = RecordSumEncoded a
- data GenericOptions :: fieldLabelModifier -> constructorTagModifier -> allNullaryToStringTag -> omitNothingFields -> sumEncoding -> unwrapUnaryRecords -> tagSingleConstructors -> Type
- data field := (value :: k)
- class ToAesonOptionsField x
- data FieldLabelModifier
- data ConstructorTagModifier
- data AllNullaryToStringTag
- data OmitNothingFields
- data SumEncoding
- data UnwrapUnaryRecords
- data TagSingleConstructors
- class StringFunction (a :: k) where
- stringFunction :: Proxy a -> String -> String
- data SnakeCase
- data Uppercase
- data Lowercase
- data DropLowercasePrefix
- data DropPrefix (str :: Symbol)
- data DropSuffix (str :: Symbol)
- data Id
- snakeCase :: String -> String
- dropLowercasePrefix :: String -> String
- class ToSumEncoding a
- data UntaggedValue
- data ObjectWithSingleField
- data TwoElemArray
- data TaggedObject (tagFieldName :: Symbol) (contentsFieldName :: Symbol)
- type family LoopWarning (n :: Type -> Type) (a :: Type) :: Constraint where ...
- newtype DisableLoopWarning a = DisableLoopWarning a
- newtype x & f = Ampersand (f x)
- unAmpersand :: (&) x f -> f x
Typeclass for aeson Options
class ToAesonOptions a where Source #
A class for defining Options for Aeson's Generic deriving support.
It is generally instantiated either by specifying all Options fields, using
GenericOptions, or simply be overriding a few specific fields, by giving a
(type-level) list. In both cases, for the sake of explicitness and to reduce the
possibility of mistakes, fields are specified in a record-like form using the
'(:=)' data type.
Users may also provide their own instances for their own data types if desired, but this should not generally be necessary.
Methods
toAesonOptions :: Proxy a -> Options Source #
Instances
newtypes for Generic encodings
Main data type for Generic encodings
newtype GenericEncoded opts a Source #
Specify your encoding scheme in terms of aeson's out-of-the box Generic
functionality. This type is never used directly, only "coerced through".
Use some of the pre-defined types supplied here for the opts phantom parameter,
or define your with an instance of ToAesonOptions.
Constructors
| GenericEncoded a |
Instances
| (ToAesonOptions opts, Generic a, GToJSON Zero (Rep a)) => ToJSON (GenericEncoded opts a) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods toJSON :: GenericEncoded opts a -> Value # toEncoding :: GenericEncoded opts a -> Encoding # toJSONList :: [GenericEncoded opts a] -> Value # toEncodingList :: [GenericEncoded opts a] -> Encoding # | |
| (ToAesonOptions opts, Generic a, GFromJSON Zero (Rep a)) => FromJSON (GenericEncoded opts a) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods parseJSON :: Value -> Parser (GenericEncoded opts a) # parseJSONList :: Value -> Parser [GenericEncoded opts a] # | |
Data type for encodings of composite "sum-of-records" types
newtype RecordSumEncoded (tagKey :: Symbol) (tagModifier :: k) (a :: Type) Source #
An encoding scheme for sums of records that are defined as distinct data types.
If we have a number of record types we want to combine under a sum, a straightforward
solution is to ensure that each each inner type uses a constructor tag, and then
derive the sum with SumEncoding := UntaggedValue. This works fine for the happy
path, but makes for very bad error messages, since it means that decoding proceeds by
trying each case in sequence. Thus error messages always pertain to the last type in
the sum, even when it wasn't the intended payload. This newtype improves on that
solution by providing the relevant error messages, by remembering the correspondence
between the constructor tag and the intended inner type/parser.
In order to work correctly, the inner types must use the TaggedObject encoding.
The same tag field name and ConstructorTagModifier must be supplied to this type.
Constructors
| RecordSumEncoded a |
Instances
| (Generic a, GToJSON Zero (Rep a)) => ToJSON (RecordSumEncoded tagKey tagModifier a) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods toJSON :: RecordSumEncoded tagKey tagModifier a -> Value # toEncoding :: RecordSumEncoded tagKey tagModifier a -> Encoding # toJSONList :: [RecordSumEncoded tagKey tagModifier a] -> Value # toEncodingList :: [RecordSumEncoded tagKey tagModifier a] -> Encoding # | |
| (Generic a, GFromJSON Zero (Rep a), GTagParserMap (Rep a), Rep a ~ D1 meta cs, Datatype meta, StringFunction tagModifier, KnownSymbol tagKey) => FromJSON (RecordSumEncoded tagKey tagModifier a) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods parseJSON :: Value -> Parser (RecordSumEncoded tagKey tagModifier a) # parseJSONList :: Value -> Parser [RecordSumEncoded tagKey tagModifier a] # | |
Phantom types for specifying Options
Many-parameter type for explicitly providing all Options fields.
data GenericOptions :: fieldLabelModifier -> constructorTagModifier -> allNullaryToStringTag -> omitNothingFields -> sumEncoding -> unwrapUnaryRecords -> tagSingleConstructors -> Type Source #
Type-level representation of the Aeson Generic deriving Options.
This representation is useful explicitly setting all options.
Instances
| (All (StringFunction :: k2 -> Constraint) (fieldLabelModifier ': (constructorTagModifier ': ([] :: [k2]))), ToSumEncoding sumEncoding, All KnownBool (allNullaryToStringTag ': (omitNothingFields ': (unwrapUnaryRecords ': (tagSingleConstructors ': ([] :: [Bool])))))) => ToAesonOptions (GenericOptions (FieldLabelModifier := fieldLabelModifier) (ConstructorTagModifier := constructorTagModifier) (AllNullaryToStringTag := allNullaryToStringTag) (OmitNothingFields := omitNothingFields) (SumEncoding := sumEncoding) (UnwrapUnaryRecords := unwrapUnaryRecords) (TagSingleConstructors := tagSingleConstructors) :: Type) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods toAesonOptions :: Proxy (GenericOptions (FieldLabelModifier := fieldLabelModifier) (ConstructorTagModifier := constructorTagModifier) (AllNullaryToStringTag := allNullaryToStringTag) (OmitNothingFields := omitNothingFields) (SumEncoding := sumEncoding) (UnwrapUnaryRecords := unwrapUnaryRecords) (TagSingleConstructors := tagSingleConstructors)) -> Options Source # | |
Types for supplying specific Options fields
Type representing field assignment
data field := (value :: k) infix 3 Source #
Phantom data type to make explicit which fields we pass for Aeson options. Polykinded in the second argument so it can take i.e. Booleans or Symbols where needed.
Also used for specifying constant values added to, or required from, an encoding. See Data.Aeson.Deriving.WithConstantFields.
Instances
Typeclass for Options fields
class ToAesonOptionsField x Source #
A class that knows about fields of aeson's Options.
Minimal complete definition
Instances
Types representing Options fields
data FieldLabelModifier Source #
Instances
| (All (StringFunction :: k2 -> Constraint) (fieldLabelModifier ': (constructorTagModifier ': ([] :: [k2]))), ToSumEncoding sumEncoding, All KnownBool (allNullaryToStringTag ': (omitNothingFields ': (unwrapUnaryRecords ': (tagSingleConstructors ': ([] :: [Bool])))))) => ToAesonOptions (GenericOptions (FieldLabelModifier := fieldLabelModifier) (ConstructorTagModifier := constructorTagModifier) (AllNullaryToStringTag := allNullaryToStringTag) (OmitNothingFields := omitNothingFields) (SumEncoding := sumEncoding) (UnwrapUnaryRecords := unwrapUnaryRecords) (TagSingleConstructors := tagSingleConstructors) :: Type) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods toAesonOptions :: Proxy (GenericOptions (FieldLabelModifier := fieldLabelModifier) (ConstructorTagModifier := constructorTagModifier) (AllNullaryToStringTag := allNullaryToStringTag) (OmitNothingFields := omitNothingFields) (SumEncoding := sumEncoding) (UnwrapUnaryRecords := unwrapUnaryRecords) (TagSingleConstructors := tagSingleConstructors)) -> Options Source # | |
| StringFunction f => ToAesonOptionsField (FieldLabelModifier := f :: Type) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods toAesonOptionsField :: Proxy (FieldLabelModifier := f) -> Options -> Options Source # | |
data ConstructorTagModifier Source #
Instances
| (All (StringFunction :: k2 -> Constraint) (fieldLabelModifier ': (constructorTagModifier ': ([] :: [k2]))), ToSumEncoding sumEncoding, All KnownBool (allNullaryToStringTag ': (omitNothingFields ': (unwrapUnaryRecords ': (tagSingleConstructors ': ([] :: [Bool])))))) => ToAesonOptions (GenericOptions (FieldLabelModifier := fieldLabelModifier) (ConstructorTagModifier := constructorTagModifier) (AllNullaryToStringTag := allNullaryToStringTag) (OmitNothingFields := omitNothingFields) (SumEncoding := sumEncoding) (UnwrapUnaryRecords := unwrapUnaryRecords) (TagSingleConstructors := tagSingleConstructors) :: Type) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods toAesonOptions :: Proxy (GenericOptions (FieldLabelModifier := fieldLabelModifier) (ConstructorTagModifier := constructorTagModifier) (AllNullaryToStringTag := allNullaryToStringTag) (OmitNothingFields := omitNothingFields) (SumEncoding := sumEncoding) (UnwrapUnaryRecords := unwrapUnaryRecords) (TagSingleConstructors := tagSingleConstructors)) -> Options Source # | |
| StringFunction f => ToAesonOptionsField (ConstructorTagModifier := f :: Type) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods toAesonOptionsField :: Proxy (ConstructorTagModifier := f) -> Options -> Options Source # | |
data AllNullaryToStringTag Source #
Instances
| (All (StringFunction :: k2 -> Constraint) (fieldLabelModifier ': (constructorTagModifier ': ([] :: [k2]))), ToSumEncoding sumEncoding, All KnownBool (allNullaryToStringTag ': (omitNothingFields ': (unwrapUnaryRecords ': (tagSingleConstructors ': ([] :: [Bool])))))) => ToAesonOptions (GenericOptions (FieldLabelModifier := fieldLabelModifier) (ConstructorTagModifier := constructorTagModifier) (AllNullaryToStringTag := allNullaryToStringTag) (OmitNothingFields := omitNothingFields) (SumEncoding := sumEncoding) (UnwrapUnaryRecords := unwrapUnaryRecords) (TagSingleConstructors := tagSingleConstructors) :: Type) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods toAesonOptions :: Proxy (GenericOptions (FieldLabelModifier := fieldLabelModifier) (ConstructorTagModifier := constructorTagModifier) (AllNullaryToStringTag := allNullaryToStringTag) (OmitNothingFields := omitNothingFields) (SumEncoding := sumEncoding) (UnwrapUnaryRecords := unwrapUnaryRecords) (TagSingleConstructors := tagSingleConstructors)) -> Options Source # | |
| KnownBool b => ToAesonOptionsField (AllNullaryToStringTag := b :: Type) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods toAesonOptionsField :: Proxy (AllNullaryToStringTag := b) -> Options -> Options Source # | |
data OmitNothingFields Source #
Instances
| (All (StringFunction :: k2 -> Constraint) (fieldLabelModifier ': (constructorTagModifier ': ([] :: [k2]))), ToSumEncoding sumEncoding, All KnownBool (allNullaryToStringTag ': (omitNothingFields ': (unwrapUnaryRecords ': (tagSingleConstructors ': ([] :: [Bool])))))) => ToAesonOptions (GenericOptions (FieldLabelModifier := fieldLabelModifier) (ConstructorTagModifier := constructorTagModifier) (AllNullaryToStringTag := allNullaryToStringTag) (OmitNothingFields := omitNothingFields) (SumEncoding := sumEncoding) (UnwrapUnaryRecords := unwrapUnaryRecords) (TagSingleConstructors := tagSingleConstructors) :: Type) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods toAesonOptions :: Proxy (GenericOptions (FieldLabelModifier := fieldLabelModifier) (ConstructorTagModifier := constructorTagModifier) (AllNullaryToStringTag := allNullaryToStringTag) (OmitNothingFields := omitNothingFields) (SumEncoding := sumEncoding) (UnwrapUnaryRecords := unwrapUnaryRecords) (TagSingleConstructors := tagSingleConstructors)) -> Options Source # | |
| KnownBool b => ToAesonOptionsField (OmitNothingFields := b :: Type) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods toAesonOptionsField :: Proxy (OmitNothingFields := b) -> Options -> Options Source # | |
data SumEncoding #
Specifies how to encode constructors of a sum datatype.
Instances
data UnwrapUnaryRecords Source #
Instances
| (All (StringFunction :: k2 -> Constraint) (fieldLabelModifier ': (constructorTagModifier ': ([] :: [k2]))), ToSumEncoding sumEncoding, All KnownBool (allNullaryToStringTag ': (omitNothingFields ': (unwrapUnaryRecords ': (tagSingleConstructors ': ([] :: [Bool])))))) => ToAesonOptions (GenericOptions (FieldLabelModifier := fieldLabelModifier) (ConstructorTagModifier := constructorTagModifier) (AllNullaryToStringTag := allNullaryToStringTag) (OmitNothingFields := omitNothingFields) (SumEncoding := sumEncoding) (UnwrapUnaryRecords := unwrapUnaryRecords) (TagSingleConstructors := tagSingleConstructors) :: Type) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods toAesonOptions :: Proxy (GenericOptions (FieldLabelModifier := fieldLabelModifier) (ConstructorTagModifier := constructorTagModifier) (AllNullaryToStringTag := allNullaryToStringTag) (OmitNothingFields := omitNothingFields) (SumEncoding := sumEncoding) (UnwrapUnaryRecords := unwrapUnaryRecords) (TagSingleConstructors := tagSingleConstructors)) -> Options Source # | |
| KnownBool b => ToAesonOptionsField (UnwrapUnaryRecords := b :: Type) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods toAesonOptionsField :: Proxy (UnwrapUnaryRecords := b) -> Options -> Options Source # | |
data TagSingleConstructors Source #
Instances
| (All (StringFunction :: k2 -> Constraint) (fieldLabelModifier ': (constructorTagModifier ': ([] :: [k2]))), ToSumEncoding sumEncoding, All KnownBool (allNullaryToStringTag ': (omitNothingFields ': (unwrapUnaryRecords ': (tagSingleConstructors ': ([] :: [Bool])))))) => ToAesonOptions (GenericOptions (FieldLabelModifier := fieldLabelModifier) (ConstructorTagModifier := constructorTagModifier) (AllNullaryToStringTag := allNullaryToStringTag) (OmitNothingFields := omitNothingFields) (SumEncoding := sumEncoding) (UnwrapUnaryRecords := unwrapUnaryRecords) (TagSingleConstructors := tagSingleConstructors) :: Type) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods toAesonOptions :: Proxy (GenericOptions (FieldLabelModifier := fieldLabelModifier) (ConstructorTagModifier := constructorTagModifier) (AllNullaryToStringTag := allNullaryToStringTag) (OmitNothingFields := omitNothingFields) (SumEncoding := sumEncoding) (UnwrapUnaryRecords := unwrapUnaryRecords) (TagSingleConstructors := tagSingleConstructors)) -> Options Source # | |
| KnownBool b => ToAesonOptionsField (TagSingleConstructors := b :: Type) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods toAesonOptionsField :: Proxy (TagSingleConstructors := b) -> Options -> Options Source # | |
class StringFunction (a :: k) where Source #
Instances
Applies snakeCase
Instances
| StringFunction SnakeCase Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic | |
Instances
| StringFunction Uppercase Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic | |
Instances
| StringFunction Lowercase Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic | |
data DropLowercasePrefix Source #
Applies dropLowercasePrefix, dropping until the first uppercase character.
Instances
| StringFunction DropLowercasePrefix Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods stringFunction :: Proxy DropLowercasePrefix -> String -> String Source # | |
data DropPrefix (str :: Symbol) Source #
Instances
| KnownSymbol str => StringFunction (DropPrefix str :: Type) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods stringFunction :: Proxy (DropPrefix str) -> String -> String Source # | |
data DropSuffix (str :: Symbol) Source #
Instances
| KnownSymbol str => StringFunction (DropSuffix str :: Type) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods stringFunction :: Proxy (DropSuffix str) -> String -> String Source # | |
Instances
| StringFunction Id Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic | |
snakeCase :: String -> String Source #
Field name modifier function that separates camel-case words by underscores (i.e. on capital letters). Also knows to handle a consecutive sequence of capitals as a single word.
dropLowercasePrefix :: String -> String Source #
Drop the first lowercase sequence (i.e. until isUpper returns True) from the start
of a string. Used for the common idiom where fields are prefixed by the type name in
all lowercase. The definition is taken from the aeson-casing package.
class ToSumEncoding a Source #
Type-level encoding for SumEncoding
Minimal complete definition
Instances
| ToSumEncoding TwoElemArray Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods | |
| ToSumEncoding ObjectWithSingleField Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods toSumEncoding :: Proxy ObjectWithSingleField -> SumEncoding Source # | |
| ToSumEncoding UntaggedValue Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods toSumEncoding :: Proxy UntaggedValue -> SumEncoding Source # | |
| (KnownSymbol tag, KnownSymbol contents) => ToSumEncoding (TaggedObject tag contents :: Type) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods toSumEncoding :: Proxy (TaggedObject tag contents) -> SumEncoding Source # | |
data UntaggedValue Source #
Instances
| ToSumEncoding UntaggedValue Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods toSumEncoding :: Proxy UntaggedValue -> SumEncoding Source # | |
data ObjectWithSingleField Source #
Instances
| ToSumEncoding ObjectWithSingleField Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods toSumEncoding :: Proxy ObjectWithSingleField -> SumEncoding Source # | |
data TwoElemArray Source #
Instances
| ToSumEncoding TwoElemArray Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods | |
data TaggedObject (tagFieldName :: Symbol) (contentsFieldName :: Symbol) Source #
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.
Instances
| (KnownSymbol tag, KnownSymbol contents) => ToSumEncoding (TaggedObject tag contents :: Type) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods toSumEncoding :: Proxy (TaggedObject tag contents) -> SumEncoding Source # | |
Safety class
type family LoopWarning (n :: Type -> Type) (a :: Type) :: Constraint where ... Source #
Used in FromJSON/ToJSON superclass constraints for newtypes that recursively modify
the instances. A guard against the common mistake of deriving encoders in terms
of such a newtype over the naked base type instead of the GenericEncoded version.
This can lead to nasty runtime bugs.
This error can be disabled by wrapping your type in DisableLoopWarning.
This should never be necessary to use the functionality of this package. It may be
required if you, for example, combine our newtypes with another library's types
for generating aeson instances.
Equations
| LoopWarning n (GenericEncoded opts a) = () | |
| LoopWarning n (RecordSumEncoded tagKey tagValMod a) = () | |
| LoopWarning n (DisableLoopWarning a) = () | |
| LoopWarning n (x & f) = LoopWarning n (f x) | |
| LoopWarning n (f x) = LoopWarning n x | |
| LoopWarning n x = TypeError (((((((((((((((((Text "Uh oh! Watch out for those infinite loops!" :$$: Text "Newtypes that recursively modify aeson instances, namely:") :$$: Text "") :$$: (Text " " :<>: ShowType n)) :$$: Text "") :$$: Text "must only be used atop a type that creates the instances non-recursively: ") :$$: Text "") :$$: Text " \65518 GenericEncoded") :$$: Text " \65518 RecordSumEncoded") :$$: Text "") :$$: Text "We observe instead the inner type: ") :$$: Text "") :$$: (Text " " :<>: ShowType x)) :$$: Text "") :$$: Text "You probably created an infinitely recursive encoder/decoder pair.") :$$: Text "See `LoopWarning` for details.") :$$: Text "This check can be disabled by wrapping the inner type in `DisableLoopWarning`.") :$$: Text "") |
newtype DisableLoopWarning a Source #
Assert that you know what you're doing and to nullify the LoopWarning constraint family.
This should not be necessary.
Constructors
| DisableLoopWarning a |
Instances
| ToJSON a => ToJSON (DisableLoopWarning a) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods toJSON :: DisableLoopWarning a -> Value # toEncoding :: DisableLoopWarning a -> Encoding # toJSONList :: [DisableLoopWarning a] -> Value # toEncodingList :: [DisableLoopWarning a] -> Encoding # | |
| FromJSON a => FromJSON (DisableLoopWarning a) Source # | |
Defined in Data.Aeson.Deriving.Internal.Generic Methods parseJSON :: Value -> Parser (DisableLoopWarning a) # parseJSONList :: Value -> Parser [DisableLoopWarning a] # | |
Convenience newtype
newtype x & f infixl 2 Source #
Constructors
| Ampersand (f x) |
unAmpersand :: (&) x f -> f x Source #