lens-family

Lens Families

Version on this page:1.2.1
LTS Haskell 16.3:2.0.0
Stackage Nightly 2020-07-04:2.0.0
Latest on Hackage:2.1.0

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BSD-3-Clause licensed by Russell O'Connor
Maintained by Russell O'Connor

Module documentation for 1.2.1

This version can be pinned in stack with:[email protected]:9407dff8059fa2886ca669694f24a5b079c5d51a0831dd5c7dd9dc949845b8d0,1750

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.