Modulemicrolens-aeson-2.5.2Haskell2010

Lens.Micro.Aeson

Traversals for Data.Aeson, based on microlens for minimal dependencies.

For basic manipulation of Aeson values, full Prism functionality isn't necessary. Since all Prisms are inherently Traversals, we provide Traversals that mimic the behaviour of the Prisms found in the original Data.Aeson.Lens.

3 classes
6 values

Packagemicrolens-aeson-2.5.2
Exports9
LanguageHaskell2010
LicenceMIT
SourceAeson.hs

Numbers

3 declarations

classclass AsNumber t where

Traverse into various number types.

Methods

_Number :: Traversal' t Scientific

Example1 expression

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

Example1 expression

>>> "[1, \"x\"]" ^? nth 1 . _NumberNothing

_Double :: Traversal' t Double
Traversal into an Double over a Value or Scientific
Example1 expression
```
>>> "[10.2]" ^? nth 0 . _DoubleJust 10.2
```
_Integer :: Traversal' t Integer
Traversal into an Integer over a Value or Scientific
Example1 expression
```
>>> "[10]" ^? nth 0 . _IntegerJust 10
```
Example1 expression
```
>>> "[10.5]" ^? nth 0 . _IntegerJust 10
```
Example1 expression
```
>>> "42" ^? _IntegerJust 42
```

Instances7AsNumber, …

AsNumber ValueDefined in microlens-aeson-2.5.2 · Lens.Micro.Aeson
AsNumber ByteStringDefined in microlens-aeson-2.5.2 · Lens.Micro.Aeson
AsNumber ByteStringDefined in microlens-aeson-2.5.2 · Lens.Micro.Aeson
AsNumber StringDefined in microlens-aeson-2.5.2 · Lens.Micro.Aeson
AsNumber ScientificDefined in microlens-aeson-2.5.2 · Lens.Micro.Aeson
AsNumber TextDefined in microlens-aeson-2.5.2 · Lens.Micro.Aeson
AsNumber TextDefined in microlens-aeson-2.5.2 · Lens.Micro.Aeson

value_Integral :: (AsNumber t, Integral a) => Traversal' t a

Access Integer Values as Integrals.

Example1 expression

>>> "[10]" ^? nth 0 . _IntegralJust 10

Example1 expression

>>> "[10.5]" ^? nth 0 . _IntegralJust 10

valuenonNull :: Traversal' Value Value

Traversal into non-Null values

Example1 expression

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

Example1 expression

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

Example1 expression

>>> "{\"a\": \"xyz\", \"b\": null}" ^? key "b" . nonNullNothing

Objects and Arrays

5 declarations

classclass AsNumber t => AsValue t where

Traverse into JSON Objects and Arrays.

Methods

_Value :: Traversal' t Value
Traverse into data that encodes a Value

_String :: Traversal' t Text

Example1 expression

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

Example1 expression

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

_Bool :: Traversal' t Bool

Example1 expression

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

Example1 expression

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

_Null :: Traversal' t ()

Example1 expression

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

Example1 expression

>>> "{\"a\": \"xyz\", \"b\": null}" ^? key "a" . _NullNothing

_Object :: Traversal' t (KeyMap Value)

Example1 expression

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

Example1 expression

>>> "{\"a\": {}, \"b\": null}" ^? key "b" . _ObjectNothing

_Array :: Traversal' t (Vector Value)

Instances6AsValue

AsValue ValueDefined in microlens-aeson-2.5.2 · Lens.Micro.Aeson
AsValue ByteStringDefined in microlens-aeson-2.5.2 · Lens.Micro.Aeson
AsValue ByteStringDefined in microlens-aeson-2.5.2 · Lens.Micro.Aeson
AsValue StringDefined in microlens-aeson-2.5.2 · Lens.Micro.Aeson
AsValue TextDefined in microlens-aeson-2.5.2 · Lens.Micro.Aeson
AsValue TextDefined in microlens-aeson-2.5.2 · Lens.Micro.Aeson

valuekey :: AsValue t => Key -> Traversal' t Value

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

Example1 expression

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

Example1 expression

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

valuemembers :: AsValue t => Traversal' t Value

A Traversal into Object properties

Example1 expression

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

Example1 expression

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

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

Like ix, but for Arrays with Int indexes

Example1 expression

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

Example1 expression

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

Example1 expression

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

valuevalues :: AsValue t => Traversal' t Value

A Traversal into Array elements

Example1 expression

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

Example1 expression

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

Decoding

1 declaration

classclass AsJSON t where

Traverse into actual encoded JSON.

Methods

_JSON :: (FromJSON a, ToJSON a) => Traversal' t a
_JSON is a Traversal from something containing JSON to something encoded in that structure.

Instances6AsJSON

AsJSON ValueDefined in microlens-aeson-2.5.2 · Lens.Micro.Aeson
AsJSON ByteStringDefined in microlens-aeson-2.5.2 · Lens.Micro.Aeson
AsJSON ByteStringDefined in microlens-aeson-2.5.2 · Lens.Micro.Aeson
AsJSON StringDefined in microlens-aeson-2.5.2 · Lens.Micro.Aeson
AsJSON TextDefined in microlens-aeson-2.5.2 · Lens.Micro.Aeson
AsJSON TextDefined in microlens-aeson-2.5.2 · Lens.Micro.Aeson