Copyright | (c) Colin Woodbury 2015 (c) Edward Kmett 2013-2014 (c) Paul Wilson 2012 |
---|---|
License | BSD3 |
Maintainer | Colin Woodbury <colingw@gmail.com> |
Safe Haskell | Trustworthy |
Language | Haskell2010 |
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.
- class AsNumber t where
- _Integral :: (AsNumber t, Integral a) => Traversal' t a
- nonNull :: Traversal' Value Value
- data Primitive
- = StringPrim !Text
- | NumberPrim !Scientific
- | BoolPrim !Bool
- | NullPrim
- class AsNumber t => AsPrimitive t where
- class AsPrimitive t => AsValue t where
- key :: AsValue t => Text -> Traversal' t Value
- members :: AsValue t => Traversal' t Value
- nth :: AsValue t => Int -> Traversal' t Value
- values :: AsValue t => Traversal' t Value
- class AsJSON t where
Numbers
class AsNumber t where Source #
Traverse into various number types.
_Number :: Traversal' t Scientific Source #
>>>
"[1, \"x\"]" ^? nth 0 . _Number
Just 1.0
>>>
"[1, \"x\"]" ^? nth 1 . _Number
Nothing
_Number :: AsPrimitive t => Traversal' t Scientific Source #
>>>
"[1, \"x\"]" ^? nth 0 . _Number
Just 1.0
>>>
"[1, \"x\"]" ^? nth 1 . _Number
Nothing
_Double :: Traversal' t Double Source #
Traversal into an Double
over a Value
, Primitive
or Scientific
>>>
"[10.2]" ^? nth 0 . _Double
Just 10.2
_Integer :: Traversal' t Integer Source #
Traversal into an Integer
over a Value
, Primitive
or Scientific
>>>
"[10]" ^? nth 0 . _Integer
Just 10
>>>
"[10.5]" ^? nth 0 . _Integer
Just 10
>>>
"42" ^? _Integer
Just 42
_Integral :: (AsNumber t, Integral a) => Traversal' t a Source #
Access Integer Value
s as Integrals.
>>>
"[10]" ^? nth 0 . _Integral
Just 10
>>>
"[10.5]" ^? nth 0 . _Integral
Just 10
nonNull :: Traversal' Value Value Source #
Traversal 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
Primitives of Value
class AsNumber t => AsPrimitive t where Source #
Traverse into various JSON primitives.
_Primitive :: Traversal' t Primitive Source #
>>>
"[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)
_Primitive :: AsValue t => Traversal' t Primitive Source #
>>>
"[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 :: Traversal' t Text Source #
>>>
"{\"a\": \"xyz\", \"b\": true}" ^? key "a" . _String
Just "xyz"
>>>
"{\"a\": \"xyz\", \"b\": true}" ^? key "b" . _String
Nothing
_Bool :: Traversal' t Bool Source #
>>>
"{\"a\": \"xyz\", \"b\": true}" ^? key "b" . _Bool
Just True
>>>
"{\"a\": \"xyz\", \"b\": true}" ^? key "a" . _Bool
Nothing
_Null :: Traversal' t () Source #
>>>
"{\"a\": \"xyz\", \"b\": null}" ^? key "b" . _Null
Just ()
>>>
"{\"a\": \"xyz\", \"b\": null}" ^? key "a" . _Null
Nothing
Objects and Arrays
class AsPrimitive t => AsValue t where Source #
Traverse into JSON Objects and Arrays.
members :: AsValue t => Traversal' t Value Source #
A Traversal into Object properties
>>>
"{\"a\": 4, \"b\": 7}" ^.. members
[Number 4.0,Number 7.0]
>>>
"{\"a\": 4, \"b\": 7}" & members . _Number %~ (* 10)
"{\"a\":40,\"b\":70}"
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 => Traversal' t Value Source #
A 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
Traverse into actual encoded JSON.