Lens Families

Version on this page:1.2.3
LTS Haskell 22.25:2.1.3
Stackage Nightly 2024-06-16:2.1.3
Latest on Hackage:2.1.3

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BSD-3-Clause licensed by Russell O'Connor
Maintained by Russell O'Connor
This version can be pinned in stack with:lens-family-1.2.3@sha256:b5ae2994a2423e3ba532840cc040579f69bdb155a32bb822daa1cf892ad64036,1721

This package provides first class functional references. In addition to the usual operations of getting, setting and composition, plus integration with monad state, lens families provide some unique features:

  • Polymorphic updating

  • Traversals

  • Cast projection functions to read-only lenses

  • Cast "toList" functions to read-only traversals

  • Cast semantic editor combinators to modify-only traversals.