generic-lens

Generically derive traversals, lenses and prisms.

https://github.com/kcsongor/generic-lens

Version on this page:	2.1.0.0
LTS Haskell 20.23:	2.2.2.0
Stackage Nightly 2023-06-04:	2.2.2.0
Latest on Hackage:	2.2.2.0

See all snapshots generic-lens appears in

BSD-3-Clause licensed by Csongor Kiss

Maintained by kiss.csongor.kiss@gmail.com

This version can be pinned in stack with:generic-lens-2.1.0.0@sha256:1af786fb2f347077266f4a137373c718cada59e2a2ed0aa0f5395d805ef9a18d,3867

Module documentation for 2.1.0.0

Data
- Data.Generics
  - Data.Generics.Internal
    - Data.Generics.Internal.VL
      - Data.Generics.Internal.VL.Iso
      - Data.Generics.Internal.VL.Lens
      - Data.Generics.Internal.VL.Prism
  - Data.Generics.Labels
  - Data.Generics.Product
  - Data.Generics.Sum
  - Data.Generics.Wrapped

Depends on 4 packages(full list with versions):

base, generic-lens-core, profunctors, text

Used by 5 packages in lts-18.28(full list with versions):

capability, hw-balancedparens, hw-packed-vector, hw-rankselect, verbosity

This library uses GHC.Generics to derive efficient optics (traversals, lenses and prisms) for algebraic data types in a type-directed way, with a focus on good type inference and error messages when possible.

The library exposes a van Laarhoven interface. For an alternative interface, supporting an opaque optic type, see generic-optics.

Changes

generic-lens-2.1.0.0 (2021-01-25)

Bump to generic-lens-core-2.1.0.0

generic-lens-2.0.0.0 (2020-02-11)

Drop support for GHC < 8.4
Better inference for field'
Param traversal now properly recurses deeply (#88)
Reorganise internals (see generic-lens-core)

Breaking API changes:

HasTypesUsing now takes 4 params
Removed HasConstraints traversal

generic-lens-1.2.0.1

Give HasAny/AsAny the same VTA behavior on 8.6 and 8.8 (Ryan Scott)

generic-lens-1.2.0.0

Add HasTypesUsing and HasTypesCustom for custom traversals (Lysxia)
Improve type errors when no Generic instance is defined
types now supports Text by default

Breaking API changes

HasType now includes a reflexive case so that every type ‘contains’ itself (Matt Parsons)
AsSubtype and Subtype now include a reflexive case so that every type is a subtype of itself

generic-lens-1.1.0.0

Fix regression in type inference for polymorphic optics
Add HasField0, HasPosition0, AsConstructor0, HasField_, HasPositon_, and AsConstructor_ (Lysxia)
types now supports Data.Word and Data.Int (Lysxia)
Add Wrapped iso for newtypes (Isaac Elliott)
Expose internals through Data.GenericLens.Internal
Add labels for prisms (Daniel Winograd-Cort)

generic-lens-1.0.0.2

Fix compile-time performance regression

generic-lens-1.0.0.1

Remove dump-core dependency
Relax upper bound on criterion (#42)

generic-lens-1.0.0.0

Traversals (types, param, constraints)
Prisms are now optimal too
Monomorphic versions of lenses and prisms also included

Breaking API changes

projectSub now returns Maybe sub instead of Either sup sub (#21)

generic-lens-0.5.1.0

Infer input type from result type (#25)
Allow changing of multiple type parameters (#24)
Allow changing of type parameters that have kinds other than * (#23)
Fix error message in subtype lens

generic-lens-0.5.0.0

Lenses and prisms are now type-changing.
More informative error messages
More readable type signatures in type errors and when using :t
Use doctest
Include examples in Haddock

Breaking API changes

The type parameters of the classes have been changed to accommodate the type-changing update:

class HasField name a s -> class HasField name s t a b etc.

Accordingly, field :: Lens' s a -> field :: Lens s t a b