MIT licensed by Edward A. Kmett
Maintained by Edward A. Kmett
This version can be pinned in stack with:lens-aeson-1.1.3@sha256:52c8eaecd2d1c2a969c0762277c4a8ee72c339a686727d5785932e72ef9c3050,1764

Module documentation for 1.1.3


Hackage Build Status

The goal of lens-aeson is to provide traversals and prisms for the Aeson library’s Value type, while obeying the Traversal/Prism laws.

Contact Information

Contributions and bug reports are welcome!

Please feel free to contact me through github or on the #haskell IRC channel on

-Edward Kmett


1.1.3 [2021.11.16]

  • Drop support for pre-8.0 versions of GHC.

1.1.2 [2021.10.09]

  • Allow building with aeson-
  • Add Index, IxValue, Ixed, At, and Each instances for KeyMap if building with aeson- or later.

1.1.1 [2021.02.17]

  • Allow building with lens-5.*.
  • The build-type has been changed from Custom to Simple. To achieve this, the doctests test suite has been removed in favor of using cabal-docspec to run the doctests.

1.1 [2019.09.26]

  • Generalize the type of _JSON from Prism' t a to Prism t t a b. If you wish to continue to use the less general type, use the newly added _JSON' prism.
  • Add pattern synonyms corresponding to the Prisms that lens-aeson provides.
  • Fix the test suite on 32-bit architectures.


  • Support doctest-0.12


  • Revamp Setup.hs to use cabal-doctest. This makes it build with Cabal-2.0, and makes the doctests work with cabal new-build and sandboxes.

  • Fix tests to work against vector-0.11
  • Documentation fixes
  • No functional changes since

  • Move lens upper bound to < 5 like the other packages in the family


  • Module migrated from lens package to Data.Aeson.Lens


  • Added members and values


  • Broadened dependencies


  • Repository initialized