lens-family

Lens Families

Version on this page:1.2.2
LTS Haskell 18.0:2.0.0@rev:1
Stackage Nightly 2021-06-19:2.1.1
Latest on Hackage:2.1.1

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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-1.2.2@sha256:7bcad928c1e027e843574983975f2a2c8a3be369eba9a381ea7a290f9fc86660,1755

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.