microlens-aeson
Law-abiding lenses for Aeson, using microlens
http://github.com/fosskers/microlens-aeson/
Version on this page: | 2.5.1 |
LTS Haskell 22.36: | 2.5.2 |
Stackage Nightly 2024-10-05: | 2.5.2 |
Latest on Hackage: | 2.5.2 |
microlens-aeson-2.5.1@sha256:cebefa1914183777a598399ab783da83ac24a50667398bf6552d62074c969f7f,1603
Module documentation for 2.5.1
- Lens
- Lens.Micro
microlens-aeson
microlens-aeson
provides Traversals for the
Aeson library’s Value
type,
while obeying the Traversal
laws.
microlens-aeson
is derived from lens-aeson
, but is based upon microlens
to reduce the amount of dependencies involved.
Here is the dependency graph for lens-aeson
:
And that for microlens-aeson
:
Usage
microlens-aeson
provides Traversals into both lazy and strict variants
of all the text types. Here are some examples:
{-# LANGUAGE OverloadedStrings #-}
import Data.Aeson
import Data.Text (Text)
import Lens.Micro.Aeson
--------------------------
-- Manipulating primatives
--------------------------
-- | Optionally getting one value
a :: Maybe Int
a = ("37" :: Text) ^? _Integer -- Just 37
-- | Setting one value within encoded JSON
b :: Maybe Text
b = "true" & _Bool .~ False -- "false"
----------------------
-- Manipulating arrays
----------------------
-- | Get all values as an Aeson type.
c :: [Value]
c = "[1, 2, 3]" ^.. values -- [Number 1.0, Number 2.0, Number 3.0]
-- | Get all values cast to some simpler number type.
d :: [Double]
d = "[1, 2, 3]" ^.. values . _Double -- [1.0, 2.0, 3.0]
-- | Access a specific index, and set a `Value` directly.
e :: Text
e = "[1,2,3]" & nth 1 .~ Number 20 -- "[1,20,3]"
-----------------------
-- Manipulating objects
-----------------------
-- | Access all values of the key/value pairs.
f :: Text
f = "{\"a\":4,\"b\":7}" & members . _Number %~ (*10) -- "{\"a\":40,\"b\":70}"
-- | Access via a given key.
g :: Maybe Value
g = ("{\"a\": 100, \"b\": 200}" :: Text) ^? key "a" -- Just (Number 100.0)
-----------------------------------
-- Aeson `Value`s from encoded JSON
-----------------------------------
h :: Maybe Text
h = "{\"a\":4,\"b\":7}" ^? _Value
-- Just (Object (fromList [("a",Number 4.0),("b",Number 7.0)]))
See the Haddock documentation for a full API specification.
Migration from Data.Aeson.Lens
The functions provided here are Traversals, not Prisms, therefore creation of encoded JSON from Haskell types like:
>>> _Bool # True :: String
"true"
is no longer possible. Otherwise, if your use cases are strictly like
those listed in the Usage section above, then you need only to switch
the import from Data.Aeson.Lens
to Lens.Micro.Aeson
.
Changes
microlens-aeson
2.5.1 (2023-08-16)
Changed
- Support for
aeson-2.2
.
2.5.0 (2022-03-19)
This is a breaking update that matches upstream changes to lens-aeson
. Luckily
the changes are mostly simplifications and improvements that better match the
aeson-2
API. Thanks to sjshuck
for his contributions to this release.
Changed
- Simplify class hierarchy to
AsNumber t => AsValue t
. Change the default signature of_Number
accordingly. - Move
_String
,_Bool
, and_Null
to be methods of classAsValue
. - Convert
HashMap Text
-based interfaces toKeyMap Key
. This changes the types of_Object
andkey
. - Change
Index Value
toKey
. - Require
base >= 4.9
, the same asaeson-2.*
does. - Drop dependencies on
deepseq
andunordered-containers
.
Removed
Primitive
and classAsPrimitive
.- Orphan
Ixed
instances forHashMap
andVector
.
2.4.1 (2022-01-21)
Added
text-2.0
support.
2.4.0 (2021-10-21)
Changed
aeson-2.0
is now the minimum required version.
2.3.1 (2020-07-19)
Fixed
- Test suite fixed to succeed deterministically on 32-bit machines.
2.3.0.3
- Readd 7.10 support. Forgive the spam.
2.3.0.2
- Bumping bounds, cleaning code.
2.3.0.1
- Enable compilation with GHC
7.8
(base-4.7
). Only when this version ofbase
is used does our typePrimitive
lose itsHashable
instance, due to a lack ofDeriveAnyClass
. Otherwise, the API is unchanged frommicrolens-aeson-2.3.0
.
2.2.0
- Various fixes to dependency version bounds
2.1.0
- Restored original
AsJSON
and_JSON
typing - Bumped
microlens
dep max
2.0.0
- Complete conversion to
microlens
- All
Prism
are nowTraversal
1.0.0.5
- Fix tests to work against vector-0.11
- Documentation fixes
- No functional changes since 1.0.0.4
1.0.0.3
- Move lens upper bound to < 5 like the other packages in the family
1
- Module migrated from lens package to Data.Aeson.Lens
0.1.2
- Added
members
andvalues
0.1.1
- Broadened dependencies
0.1
- Repository initialized