generic-aeson: Derivation of Aeson instances using GHC generics.

[ bsd3, data, library ] [ Propose Tags ]
Versions 0.1,,,, 0.1.1,,,,,,,,,,,
Change log
Dependencies aeson (>=0.6 && <1.3), attoparsec (>=0.11 && <0.14), base (>=4.4 && <4.11), generic‑deriving (>=1.6 && <1.13), ghc‑prim, mtl (>=2.0 && <2.3), tagged (>=0.2 && <0.9), text (>=0.11 && <1.3), unordered‑containers (==0.2.*), vector (>=0.10 && <0.13) [details]
License BSD-3-Clause
Author Silk
Revised Revision 2 made by AdamBergmark at Tue Dec 12 08:29:54 UTC 2017
Category Data
Source repo head: git clone
Uploaded by AdamBergmark at Sun Apr 23 11:02:53 UTC 2017
Distributions LTSHaskell:, NixOS:, openSUSE:
Downloads 10256 total (40 in the last 30 days)
Rating (no votes yet) [estimated by rule of succession]
Your Rating
  • λ
  • λ
  • λ
Status Docs available [build log]
Last success reported on 2017-04-23 [all 1 reports]
Hackage Matrix CI

Derivation of Aeson instances using GHC generics.

[Skip to Readme]




Note: This package has metadata revisions in the cabal description newer than included in the tarball. To unpack the package including the revisions, use 'cabal get'.

Maintainer's Corner

For package maintainers and hackage trustees

Readme for generic-aeson-

[back to package description]


Build Status

The structure of the generated JSON is meant to be close to idiomatic JSON. This means:

  • Enumerations (data types containing constructors without fields) are converted to JSON strings.

  • Record fields become JSON keys.

  • Data types with one unlabeled field convert to just that field.

  • Data types with multiple unlabeled fields become arrays.

  • Multiple constructors are represented by keys.

  • Maybe values are either an absent key, or the value.

  • Leading and trailing underscores are removed from constructor names and record fields

See tests/Main.hs in json-schema for more examples.

How does generic-aeson compare to the TH/Generics already present in aeson?

generic-aeson contains more special cases for creating more concise and idiomatic json. If you're working with the JSON representation directly generic-aeson should feel more natural.

Will the generated format ever change?

Changing the format would incur a breaking change to every API that uses generic-aeson so we must keep it intact.

If we find a bug where the fix changes the format we need to create a new package or version the generation code.


json-schema has generic derivation of schemas that match the generic-aeson format.