generic-lens-2.3.0.0 (2025-08-27)

Tested with GHC 8.4 - 9.14 alpha1.

• Add OverloadedLabels support for positional lenses, e.g. #3 as an abbreviation for position @3, starting with GHC 9.6.

Breaking API changes:

• AsType now includes a reflexive case for consistency with HasType: every type can be treated 'as' itself.

generic-lens-2.2.2.0 (2023-04-15)

• Support unprefixed constructor prisms on GHC 9.6 (#152)

generic-lens-2.2.1.0 (2022-01-22)

• GHC 9.2 compatibility

generic-lens-2.2.0.0 (2021-07-13)

• GHC 9.0 compatibility

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