lens-aeson-1.2.3: Law-abiding lenses for aeson
Copyright(c) Edward Kmett 2013-2019 (c) Paul Wilson 2012
LicenseBSD3
MaintainerEdward Kmett <ekmett@gmail.com>
Stabilityexperimental
Portabilitynon-portable
Safe HaskellTrustworthy
LanguageHaskell2010

Data.Aeson.Lens

Description

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

Synopsis

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

_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

_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

AsValue ByteString Source # 
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Defined in Data.Aeson.Lens

AsValue ByteString Source # 
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Defined in Data.Aeson.Lens

AsValue Text Source # 
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Defined in Data.Aeson.Lens

AsValue Text Source # 
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AsValue String Source # 
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Defined in Data.Aeson.Lens

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 ByteStrings, 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 ByteStrings 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

IsKey ByteString Source #

This instance assumes that you are dealing with UTF-8–encoded ByteStrings, 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 ByteStrings 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

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 # 
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Defined in Data.Aeson.Lens

IsKey String Source # 
Instance details

Defined in Data.Aeson.Lens

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

AsJSON ByteString Source # 
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Defined in Data.Aeson.Lens

AsJSON Text Source # 
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Defined in Data.Aeson.Lens

Methods

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

AsJSON Text Source # 
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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

Plated Value Source # 
Instance details

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 #