Data.Aeson.Lens

Numbers

class AsNumber t where

Minimal complete definition

Nothing

Methods

_Number :: Prism' t Scientific

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

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

_Double :: Prism' t Double

Prism into an Double over a Value, Primitive or Scientific

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

_Integer :: Prism' t Integer

Prism into an Integer over a Value, Primitive or Scientific

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

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

Instances

AsNumber String

AsNumber ByteString

AsNumber Scientific

AsNumber Value

AsNumber Primitive

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

Access Integer Values as Integrals.

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

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

nonNull :: Prism' Value Value

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

Primitive

data Primitive

Primitives of Value

Constructors

StringPrim !Text

NumberPrim !Scientific

BoolPrim !Bool

NullPrim

Instances

Eq Primitive

Data Primitive

Ord Primitive

Show Primitive

AsPrimitive Primitive

AsNumber Primitive

Typeable * Primitive

class AsNumber t => AsPrimitive t where

Minimal complete definition

Nothing

Methods

_Primitive :: Prism' t Primitive

>>> "[1, \"x\", null, true, false]" ^? nth 0 . _Primitive
Just (NumberPrim 1.0)

>>> "[1, \"x\", null, true, false]" ^? nth 1 . _Primitive
Just (StringPrim "x")

>>> "[1, \"x\", null, true, false]" ^? nth 2 . _Primitive
Just NullPrim

>>> "[1, \"x\", null, true, false]" ^? nth 3 . _Primitive
Just (BoolPrim True)

>>> "[1, \"x\", null, true, false]" ^? nth 4 . _Primitive
Just (BoolPrim False)

_String :: Prism' t Text

_Bool :: Prism' t Bool

_Null :: Prism' t ()

Instances

AsPrimitive String

AsPrimitive ByteString

AsPrimitive Value

AsPrimitive Primitive

Objects and Arrays

class AsPrimitive t => AsValue t where

Minimal complete definition

Nothing

Methods

_Value :: Prism' t Value

>>> "[1,2,3]" ^? _Value
Just (Array (fromList [Number 1.0,Number 2.0,Number 3.0]))

_Object :: Prism' t (HashMap Text Value)

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

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

_Array :: Prism' t (Vector Value)

>>> "[1,2,3]" ^? _Array
Just (fromList [Number 1.0,Number 2.0,Number 3.0])

Instances

AsValue String

AsValue ByteString

AsValue Value

key :: AsValue t => Text -> Traversal' t Value

Like ix, but for Object with Text 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

members :: AsValue t => IndexedTraversal' Text t Value

An indexed Traversal into Object properties

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

>>> "{\"a\": 4, \"b\": 7}" & members . _Number *~ 10
"{\"a\":40,\"b\":70}"

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

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

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]"

Decoding

class AsJSON t where

Minimal complete definition

Nothing

Methods

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

A Prism into Value on lazy ByteStrings.

Instances

AsJSON String

AsJSON ByteString

AsJSON Value