Copyright	(c) Edward Kmett 2013-2019 (c) Paul Wilson 2012
License	BSD3
Maintainer	Edward Kmett <ekmett@gmail.com>
Stability	experimental
Portability	non-portable
Safe Haskell	Trustworthy
Language	Haskell2010

Data.Aeson.Lens

Contents

Numbers
Objects and Arrays
Decoding
Pattern Synonyms
Orphan instances

Description

This module also exports orphan Ixed Value and Plated Value instances.

Synopsis

class AsNumber t where
- _Number :: Prism' t Scientific
- _Double :: Prism' t Double
- _Integer :: Prism' t Integer
_Integral :: (AsNumber t, Integral a) => Prism' t a
nonNull :: Prism' Value Value
class AsNumber t => AsValue t where
- _Value :: Prism' t Value
- _String :: Prism' t Text
- _Bool :: Prism' t Bool
- _Null :: Prism' t ()
- _Object :: Prism' t (KeyMap Value)
- _Array :: Prism' t (Vector Value)
key :: AsValue t => Key -> Traversal' t Value
atKey :: AsValue t => Key -> Traversal' t (Maybe Value)
members :: AsValue t => IndexedTraversal' Key t Value
nth :: AsValue t => Int -> Traversal' t Value
values :: AsValue t => IndexedTraversal' Int t Value
class IsKey t where
- _Key :: Iso' t Key
class AsJSON t where
- _JSON :: (FromJSON a, ToJSON b) => Prism t t a b
_JSON' :: (AsJSON t, FromJSON a, ToJSON a) => Prism' t a
pattern JSON :: (FromJSON a, ToJSON a, AsJSON t) => a -> t
pattern Value_ :: (FromJSON a, ToJSON a) => a -> Value
pattern Number_ :: AsNumber t => Scientific -> t
pattern Double :: AsNumber t => Double -> t
pattern Integer :: AsNumber t => Integer -> t
pattern Integral :: (AsNumber t, Integral a) => a -> t
pattern Bool_ :: AsValue t => Bool -> t
pattern String_ :: AsValue t => Text -> t
pattern Null_ :: AsValue t => t
pattern Key_ :: IsKey t => Key -> t

Numbers

class AsNumber t where Source #

Minimal complete definition

Nothing

Methods

_Number :: Prism' t Scientific Source #

>>> "[1, \"x\"]" ^? nth 0 . _Number
Just 1.0

>>> "[1, \"x\"]" ^? nth 1 . _Number
Nothing

default _Number :: AsValue t => Prism' t Scientific Source #

_Double :: Prism' t Double Source #

Prism into an Double over a Value or Scientific

>>> "[10.2]" ^? nth 0 . _Double
Just 10.2

_Integer :: Prism' t Integer Source #

Prism into an Integer over a Value or Scientific

>>> "[10]" ^? nth 0 . _Integer
Just 10

>>> "[10.5]" ^? nth 0 . _Integer
Just 10

>>> "42" ^? _Integer
Just 42

Instances

Instances details

AsNumber Value Source #
Instance details Defined in Data.Aeson.Lens Methods _Number :: Prism' Value Scientific Source # _Double :: Prism' Value Double Source # _Integer :: Prism' Value Integer Source #
AsNumber ByteString Source #
Instance details Defined in Data.Aeson.Lens Methods _Number :: Prism' ByteString Scientific Source # _Double :: Prism' ByteString Double Source # _Integer :: Prism' ByteString Integer Source #
AsNumber ByteString Source #
Instance details Defined in Data.Aeson.Lens Methods _Number :: Prism' ByteString Scientific Source # _Double :: Prism' ByteString Double Source # _Integer :: Prism' ByteString Integer Source #
AsNumber Scientific Source #
Instance details Defined in Data.Aeson.Lens Methods _Number :: Prism' Scientific Scientific Source # _Double :: Prism' Scientific Double Source # _Integer :: Prism' Scientific Integer Source #
AsNumber Text Source #
Instance details Defined in Data.Aeson.Lens Methods _Number :: Prism' Text Scientific Source # _Double :: Prism' Text Double Source # _Integer :: Prism' Text Integer Source #
AsNumber Text Source #
Instance details Defined in Data.Aeson.Lens Methods _Number :: Prism' Text Scientific Source # _Double :: Prism' Text Double Source # _Integer :: Prism' Text Integer Source #
AsNumber String Source #
Instance details Defined in Data.Aeson.Lens Methods _Number :: Prism' String Scientific Source # _Double :: Prism' String Double Source # _Integer :: Prism' String Integer Source #

_Integral :: (AsNumber t, Integral a) => Prism' t a Source #

Access Integer Values as Integrals.

>>> "[10]" ^? nth 0 . _Integral
Just 10

>>> "[10.5]" ^? nth 0 . _Integral
Just 10

nonNull :: Prism' Value Value Source #

Prism into non-Null values

>>> "{\"a\": \"xyz\", \"b\": null}" ^? key "a" . nonNull
Just (String "xyz")

>>> "{\"a\": {}, \"b\": null}" ^? key "a" . nonNull
Just (Object (fromList []))

>>> "{\"a\": \"xyz\", \"b\": null}" ^? key "b" . nonNull
Nothing

Objects and Arrays

class AsNumber t => AsValue t where Source #

Minimal complete definition

_Value

Methods

_Value :: Prism' t Value Source #

>>> preview _Value "[1,2,3]" == Just (Array (Vector.fromList [Number 1.0,Number 2.0,Number 3.0]))
True

_String :: Prism' t Text Source #

>>> "{\"a\": \"xyz\", \"b\": true}" ^? key "a" . _String
Just "xyz"

>>> "{\"a\": \"xyz\", \"b\": true}" ^? key "b" . _String
Nothing

>>> _Object._Wrapped # [("key" :: Key, _String # "value")] :: String
"{\"key\":\"value\"}"

_Bool :: Prism' t Bool Source #

>>> "{\"a\": \"xyz\", \"b\": true}" ^? key "b" . _Bool
Just True

>>> "{\"a\": \"xyz\", \"b\": true}" ^? key "a" . _Bool
Nothing

>>> _Bool # True :: String
"true"

>>> _Bool # False :: String
"false"

_Null :: Prism' t () Source #

>>> "{\"a\": \"xyz\", \"b\": null}" ^? key "b" . _Null
Just ()

>>> "{\"a\": \"xyz\", \"b\": null}" ^? key "a" . _Null
Nothing

>>> _Null # () :: String
"null"

_Object :: Prism' t (KeyMap Value) Source #

>>> "{\"a\": {}, \"b\": null}" ^? key "a" . _Object
Just (fromList [])

>>> "{\"a\": {}, \"b\": null}" ^? key "b" . _Object
Nothing

>>> _Object._Wrapped # [("key" :: Key, _String # "value")] :: String
"{\"key\":\"value\"}"

_Array :: Prism' t (Vector Value) Source #

>>> preview _Array "[1,2,3]" == Just (Vector.fromList [Number 1.0,Number 2.0,Number 3.0])
True

Instances

Instances details

AsValue Value Source #
Instance details Defined in Data.Aeson.Lens Methods _Value :: Prism' Value Value Source # _String :: Prism' Value Text Source # _Bool :: Prism' Value Bool Source # _Null :: Prism' Value () Source # _Object :: Prism' Value (KeyMap Value) Source # _Array :: Prism' Value (Vector Value) Source #
AsValue ByteString Source #
Instance details Defined in Data.Aeson.Lens Methods _Value :: Prism' ByteString Value Source # _String :: Prism' ByteString Text Source # _Bool :: Prism' ByteString Bool Source # _Null :: Prism' ByteString () Source # _Object :: Prism' ByteString (KeyMap Value) Source # _Array :: Prism' ByteString (Vector Value) Source #
AsValue ByteString Source #
Instance details Defined in Data.Aeson.Lens Methods _Value :: Prism' ByteString Value Source # _String :: Prism' ByteString Text Source # _Bool :: Prism' ByteString Bool Source # _Null :: Prism' ByteString () Source # _Object :: Prism' ByteString (KeyMap Value) Source # _Array :: Prism' ByteString (Vector Value) Source #
AsValue Text Source #
Instance details Defined in Data.Aeson.Lens Methods _Value :: Prism' Text Value Source # _String :: Prism' Text Text Source # _Bool :: Prism' Text Bool Source # _Null :: Prism' Text () Source # _Object :: Prism' Text (KeyMap Value) Source # _Array :: Prism' Text (Vector Value) Source #
AsValue Text Source #
Instance details Defined in Data.Aeson.Lens Methods _Value :: Prism' Text Value Source # _String :: Prism' Text Text0 Source # _Bool :: Prism' Text Bool Source # _Null :: Prism' Text () Source # _Object :: Prism' Text (KeyMap Value) Source # _Array :: Prism' Text (Vector Value) Source #
AsValue String Source #
Instance details Defined in Data.Aeson.Lens Methods _Value :: Prism' String Value Source # _String :: Prism' String Text Source # _Bool :: Prism' String Bool Source # _Null :: Prism' String () Source # _Object :: Prism' String (KeyMap Value) Source # _Array :: Prism' String (Vector Value) Source #

key :: AsValue t => Key -> Traversal' t Value Source #

Like ix, but for Value with Key indices. This often has better inference than ix when used with OverloadedStrings.

>>> "{\"a\": 100, \"b\": 200}" ^? key "a"
Just (Number 100.0)

>>> "[1,2,3]" ^? key "a"
Nothing

atKey :: AsValue t => Key -> Traversal' t (Maybe Value) Source #

Like key, but uses at instead of ix. This is handy when adding and removing object keys:

>>> "{\"a\": 100, \"b\": 200}" & atKey "a" .~ Nothing
"{\"b\":200}"

>>> "{\"a\": 100, \"b\": 200}" & atKey "c" ?~ String "300"
"{\"a\":100,\"b\":200,\"c\":\"300\"}"

members :: AsValue t => IndexedTraversal' Key t Value Source #

An indexed Traversal into Object properties

>>> Data.List.sort ("{\"a\": 4, \"b\": 7}" ^@.. members . _Number)
[("a",4.0),("b",7.0)]

>>> "{\"a\": 4}" & members . _Number *~ 10
"{\"a\":40}"

nth :: AsValue t => Int -> Traversal' t Value Source #

Like ix, but for Arrays with Int indexes

>>> "[1,2,3]" ^? nth 1
Just (Number 2.0)

>>> "{\"a\": 100, \"b\": 200}" ^? nth 1
Nothing

>>> "[1,2,3]" & nth 1 .~ Number 20
"[1,20,3]"

values :: AsValue t => IndexedTraversal' Int t Value Source #

An indexed Traversal into Array elements

>>> "[1,2,3]" ^.. values
[Number 1.0,Number 2.0,Number 3.0]

>>> "[1,2,3]" & values . _Number *~ 10
"[10,20,30]"

class IsKey t where Source #

Methods

_Key :: Iso' t Key Source #

_Key is an Iso from something to a Key. This is primarily intended for situations where one wishes to use object keys that are not string literals and therefore must be converted:

>>> let k = "a" :: Text
>>> "{\"a\": 100, \"b\": 200}" ^? key (k ^. _Key)
Just (Number 100.0)

Note that applying _Key directly to a string literal (e.g., "a" ^. _Key) will likely not typecheck when OverloadedStrings is enabled.

Instances

Instances details

IsKey Key Source #
Instance details Defined in Data.Aeson.Lens Methods _Key :: Iso' Key Key Source #
IsKey ByteString Source #	This instance assumes that you are dealing with UTF-8–encoded `ByteString`s, as this is the encoding that RFC 8259 requires JSON values to use. As such, this is not a full `Iso`, since non–UTF-8–encoded `ByteString`s will not roundtrip: `>>>` `let str = view _Key ("\255" :: Strict.ByteString)``>>>` `str`"\65533" `>>>` `view (from _Key) str :: Strict.ByteString`"\239\191\189"
Instance details Defined in Data.Aeson.Lens Methods _Key :: Iso' ByteString Key Source #
IsKey ByteString Source #	This instance assumes that you are dealing with UTF-8–encoded `ByteString`s, as this is the encoding that RFC 8259 requires JSON values to use. As such, this is not a full `Iso`, since non–UTF-8–encoded `ByteString`s will not roundtrip: `>>>` `let str = view _Key ("\255" :: Lazy.ByteString)``>>>` `str`"\65533" `>>>` `view (from _Key) str :: Lazy.ByteString`"\239\191\189"
Instance details Defined in Data.Aeson.Lens Methods _Key :: Iso' ByteString Key Source #
IsKey Text Source #
Instance details Defined in Data.Aeson.Lens Methods _Key :: Iso' Text Key Source #
IsKey Text Source #
Instance details Defined in Data.Aeson.Lens Methods _Key :: Iso' Text Key Source #
IsKey ShortText Source #
Instance details Defined in Data.Aeson.Lens Methods _Key :: Iso' ShortText Key Source #
IsKey String Source #
Instance details Defined in Data.Aeson.Lens Methods _Key :: Iso' String Key Source #

Decoding

class AsJSON t where Source #

Methods

_JSON :: (FromJSON a, ToJSON b) => Prism t t a b Source #

_JSON is a Prism from something containing JSON to something encoded in that structure

Instances

Instances details

AsJSON Value Source #
Instance details Defined in Data.Aeson.Lens Methods _JSON :: (FromJSON a, ToJSON b) => Prism Value Value a b Source #
AsJSON ByteString Source #
Instance details Defined in Data.Aeson.Lens Methods _JSON :: (FromJSON a, ToJSON b) => Prism ByteString ByteString a b Source #
AsJSON ByteString Source #
Instance details Defined in Data.Aeson.Lens Methods _JSON :: (FromJSON a, ToJSON b) => Prism ByteString ByteString a b Source #
AsJSON Text Source #
Instance details Defined in Data.Aeson.Lens Methods _JSON :: (FromJSON a, ToJSON b) => Prism Text Text a b Source #
AsJSON Text Source #
Instance details Defined in Data.Aeson.Lens Methods _JSON :: (FromJSON a, ToJSON b) => Prism Text Text a b Source #
AsJSON String Source #
Instance details Defined in Data.Aeson.Lens Methods _JSON :: (FromJSON a, ToJSON b) => Prism String String a b Source #

_JSON' :: (AsJSON t, FromJSON a, ToJSON a) => Prism' t a Source #

Pattern Synonyms

pattern JSON :: (FromJSON a, ToJSON a, AsJSON t) => a -> t Source #

pattern Value_ :: (FromJSON a, ToJSON a) => a -> Value Source #

pattern Number_ :: AsNumber t => Scientific -> t Source #

pattern Double :: AsNumber t => Double -> t Source #

pattern Integer :: AsNumber t => Integer -> t Source #

pattern Integral :: (AsNumber t, Integral a) => a -> t Source #

pattern Bool_ :: AsValue t => Bool -> t Source #

pattern String_ :: AsValue t => Text -> t Source #

pattern Null_ :: AsValue t => t Source #

pattern Key_ :: IsKey t => Key -> t Source #

Orphan instances

Ixed Value Source #
Instance details Methods ix :: Index Value -> Traversal' Value (IxValue Value)
Plated Value Source #
Instance details Methods plate :: Traversal' Value Value
At (KeyMap v) Source #
Instance details Methods at :: Index (KeyMap v) -> Lens' (KeyMap v) (Maybe (IxValue (KeyMap v)))
Ixed (KeyMap v) Source #
Instance details Methods ix :: Index (KeyMap v) -> Traversal' (KeyMap v) (IxValue (KeyMap v))
Wrapped (KeyMap v) Source #
Instance details Associated Types type Unwrapped (KeyMap v) Methods _Wrapped' :: Iso' (KeyMap v) (Unwrapped (KeyMap v))
t ~ KeyMap v' => Rewrapped (KeyMap v) t Source #	Use `iso toList fromList`. Unwrapping returns some permutation of the list.
Instance details
Each (KeyMap a) (KeyMap b) a b Source #
Instance details Methods each :: Traversal (KeyMap a) (KeyMap b) a b