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| Name: ghc-lens | Distribution: openSUSE Tumbleweed |
| Version: 5.0.1 | Vendor: openSUSE |
| Release: 2.1 | Build date: Tue Jun 1 15:21:15 2021 |
| Group: Unspecified | Build host: obs-arm-5 |
| Size: 5981168 | Source RPM: ghc-lens-5.0.1-2.1.src.rpm |
| Packager: http://bugs.opensuse.org | |
| Url: https://hackage.haskell.org/package/lens | |
| Summary: Lenses, Folds and Traversals | |
This package comes "Batteries Included" with many useful lenses for the types commonly used from the Haskell Platform, and with tools for automatically generating lenses and isomorphisms for user-supplied data types. The combinators in 'Control.Lens' provide a highly generic toolbox for composing families of getters, folds, isomorphisms, traversals, setters and lenses and their indexed variants. An overview, with a large number of examples can be found in the <https://github.com/ekmett/lens#lens-lenses-folds-and-traversals README>. An introductory video on the style of code used in this library by Simon Peyton Jones is available from <http://skillsmatter.com/podcast/scala/lenses-compositional-data-access-and-manipulation Skills Matter>. A video on how to use lenses and how they are constructed is available on <http://youtu.be/cefnmjtAolY?hd=1 youtube>. Slides for that second talk can be obtained from <http://comonad.com/haskell/Lenses-Folds-and-Traversals-NYC.pdf comonad.com>. More information on the care and feeding of lenses, including a brief tutorial and motivation for their types can be found on the <https://github.com/ekmett/lens/wiki lens wiki>. A small game of 'pong' and other more complex examples that manage their state using lenses can be found in the <https://github.com/ekmett/lens/blob/master/examples/ example folder>. /Lenses, Folds and Traversals/ With some signatures simplified, the core of the hierarchy of lens-like constructions looks like: <<http://i.imgur.com/ALlbPRa.png>> <images/Hierarchy.png (Local Copy)> You can compose any two elements of the hierarchy above using '(.)' from the 'Prelude', and you can use any element of the hierarchy as any type it linked to above it. The result is their lowest upper bound in the hierarchy (or an error if that bound doesn't exist). For instance: * You can use any 'Traversal' as a 'Fold' or as a 'Setter'. * The composition of a 'Traversal' and a 'Getter' yields a 'Fold'. /Minimizing Dependencies/ If you want to provide lenses and traversals for your own types in your own libraries, then you can do so without incurring a dependency on this (or any other) lens package at all. /e.g./ for a data type: > data Foo a = Foo Int Int a You can define lenses such as > -- bar :: Lens' (Foo a) Int > bar :: Functor f => (Int -> f Int) -> Foo a -> f (Foo a) > bar f (Foo a b c) = fmap (a' -> Foo a' b c) (f a) > -- quux :: Lens (Foo a) (Foo b) a b > quux :: Functor f => (a -> f b) -> Foo a -> f (Foo b) > quux f (Foo a b c) = fmap (Foo a b) (f c) without the need to use any type that isn't already defined in the 'Prelude'. And you can define a traversal of multiple fields with 'Control.Applicative.Applicative': > -- traverseBarAndBaz :: Traversal' (Foo a) Int > traverseBarAndBaz :: Applicative f => (Int -> f Int) -> Foo a -> f (Foo a) > traverseBarAndBaz f (Foo a b c) = Foo <$> f a <*> f b <*> pure c What is provided in this library is a number of stock lenses and traversals for common haskell types, a wide array of combinators for working them, and more exotic functionality, (/e.g./ getters, setters, indexed folds, isomorphisms).
BSD-2-Clause
* Mon May 17 2021 psimons@suse.com
- Update lens to version 5.0.1 revision 1.
Upstream has revised the Cabal build instructions on Hackage.
* Wed Feb 24 2021 psimons@suse.com
- Update lens to version 5.0.1.
5.0.1 [2021.02.24]
- -----------------
* Fix a bug in which `makeLenses` could produce ill kinded optics for
poly-kinded datatypes in certain situations.
* Fri Feb 19 2021 psimons@suse.com
- Update lens to version 5.
5 [2021.02.17]
- -------------
* Support building with GHC 9.0.
* Remove the `Swapped` type class in favor of `Swap` from the `assoc` package.
* Remove the `Strict` type class in favor of `Strict` from the `strict` package.
The `swapped`, `strict` and `lazy` isomorphisms are now defined using "new" type classes.
Users which define own instances of old type classes are advised to
define instances of the new ones.
```haskell
import qualified Data.Bifunctor.Swap as Swap
import qualified Control.Lens as Lens
instance Swap.Swap MyType where
swap = ...
[#]if !MIN_VERSION_lens(4,20,0)
instance Lens.Swapped MyType where
swapped = iso Swap.swap Swap.swap
[#]endif
```
* The `FunctorWithIndex`, `FoldableWithIndex` and `TraversableWithIndex` type classes
have been migrated to a new package,
[`indexed-traversable`](https://hackage.haskell.org/package/indexed-traversable).
The `imapped`, `ifolded` and `itraversed` methods are now top-level functions.
If you are not defining these methods in your instances,
you don't need to change your definitions.
Beware: the `optics-core` package (versions <0.4) defines similar classes,
and will also migrate to use `indexed-traversable` classes. Therefore, you
might get duplicate instance errors if your package defines both.
If you define your own `FunctorWithIndex` etc. instances,
we recommend that you depend directly on the `indexed-traversable` package.
If you want to continue support `lens-4` users, you may write
```haskell
- - from indexed-traversable
import Data.Functor.WithIndex
- - from lens
import qualified Control.Lens as L
- - your (indexed) container
data MySeq a = ...
- - indexed-traversable instance
instance FunctorWithIndex Int MySeq where imap = ...
instance FoldableWithIndex Int MySeq where ifoldMap = ...
instance TraversableWithIndex Int MySeq where itraverse = ...
- - lens <5 instance, note the !
[#]if !MIN_VERSION_lens(5,0,0)
instance L.FunctorWithIndex Int MySeq where imap = imap
instance L.FoldableWithIndex Int MySeq where ifoldMap = ifoldMap
instance L.TraversableWithIndex Int MySeq where itraverse = itraverse
[#]endif
```
In other words, always provide `indexed-traversable` instances.
If your package depends on `lens` and allows `lens-4`,
you should additionally provide instances for `lens-4` type classes
that can reuse the `indexed-traversable` instances.
* Make the functions in `Control.Lens.TH` work more robustly with poly-kinded
data types. This can cause a breaking change under certain situations:
* TH-generated optics for poly-kinded data types are now much more likely to
mention kind variables in their definitions, which will require enabling
the `PolyKinds` extension at use sites in order to typecheck.
* Because TH-generated optics now quantify more kind variables than they did
previously, this can affect the order of visible type applications.
* Generalize the types of `generic` and `generic1` to allow type-changing
updates. If you wish to use the old, more restricted types of these
functions, use `simple . generic` or `simple . generic1` instead.
* Add `Control.Lens.Profunctor` with conversion functions to and from
profunctor optic representation.
* Add `Control.Lens.Review.reviewing`, which is like `review` but with a more
polymorphic type.
* Mark `Control.Lens.Equality` as Trustworthy.
* The build-type has been changed from `Custom` to `Simple`.
To achieve this, the `doctests` test suite has been removed in favor of using [`cabal-docspec`](https://github.com/phadej/cabal-extras/tree/master/cabal-docspec) to run the doctests.
* Use `alterF` in `At (HashMap k)` instance implementation.
* Use `alterF` in `At` and `Contains` instances for `Set`, `IntSet`, and
`HashSet`.
* Avoid re-inserting keys already present in `ix` for `Set`, `IntSet`,
and `HashSet`. For `Set` and `HashSet`, this changes the semantics
slightly; if the user-supplied key is `==` to one already present in
the set, then the latter will not be replaced in the result.
* Consume `()` values lazily in `Control.Lens.At`.
* Mon Feb 08 2021 psimons@suse.com
- Update lens to version 4.19.2 revision 5.
Upstream has revised the Cabal build instructions on Hackage.
* Sun Jan 31 2021 psimons@suse.com
- Update lens to version 4.19.2 revision 4.
Upstream has revised the Cabal build instructions on Hackage.
* Wed Jan 20 2021 psimons@suse.com
- Update lens to version 4.19.2 revision 3.
Upstream has revised the Cabal build instructions on Hackage.
* Thu Dec 17 2020 Ondřej Súkup <mimi.vx@gmail.com>
- disable %{ix86} build
* Tue Oct 06 2020 psimons@suse.com
- Update lens to version 4.19.2 revision 2.
Upstream has revised the Cabal build instructions on Hackage.
* Mon Aug 31 2020 psimons@suse.com
- Update lens to version 4.19.2 revision 1.
Upstream has revised the Cabal build instructions on Hackage.
* Tue Aug 18 2020 Peter Simons <psimons@suse.com>
- Replace %setup -q with the more modern %autosetup macro.
* Tue Jun 16 2020 Peter Simons <psimons@suse.com>
- Re-generate file with latest version of spec-cleaner.
* Wed May 06 2020 psimons@suse.com
- Update lens to version 4.19.2.
4.19.2 [2020.04.15]
- ------------------
* Remove the test suite's dependency on `test-framework-th`.
* Thu Feb 27 2020 psimons@suse.com
- Update lens to version 4.19.1.
4.19.1 [2020.02.13]
- ------------------
* Fix a bug introduced in 4.19 where using `_TupE` to `preview` a value would
always fail.
* Fri Feb 07 2020 psimons@suse.com
- Update lens to version 4.19.
4.19 [2020.02.03]
- ----------------
* Support building with GHC 8.10.
* The types of `_TupE` and `_UnboxedTupE` are now `Prism' Exp [Maybe Exp]`
when built against `template-haskell-2.16` or later to reflect the new
types of `TupE` and `UnboxedTupE`.
* Add `_ForallVisT` and `_BytesPrimL` prisms when building against
`template-haskell-2.16` or later.
* Make `<>~` and `<>=` and their `<op` and `<<op` state variants require only
`Semigroup`, not `Monoid`.
* Add `{Functor,Foldable,Traversable}WithIndex` instances for
`Control.Applicative.Const` and `Data.Functor.Constant.Constant`.
* Fri Nov 08 2019 Peter Simons <psimons@suse.com>
- Drop obsolete group attributes.
* Sat Sep 14 2019 psimons@suse.com
- Update lens to version 4.18.1.
4.18.1 [2019.09.13]
- ------------------
* Remove the use of `cpp-options: -traditional`. This should be unnecessary
on all versions of GHC that `lens` supports, as modern GHCs already use
`-traditional` internally during preprocessing. More critically, the use
of `cpp-options: -traditional` breaks profiling builds on GHC 8.8
(see https://gitlab.haskell.org/ghc/ghc/issues/17185).
* Sat Sep 07 2019 psimons@suse.com
- Update lens to version 4.18.
Upstream has edited the change log file since the last release in
a non-trivial way, i.e. they did more than just add a new entry
at the top. You can review the file at:
http://hackage.haskell.org/package/lens-4.18/src/CHANGELOG.markdown
* Thu Aug 08 2019 Peter Simons <psimons@suse.com>
- Update Cabal file to allow building with call-stack 0.2.x.
* Tue Jun 11 2019 Peter Simons <psimons@suse.com>
- Update Cabal file for more accurate build dependencies.
* Tue Apr 30 2019 psimons@suse.com
- Update lens to version 4.17.1.
4.17.1 [2019.04.26]
- ------------------
* Support `th-abstraction-0.3.0.0` or later.
* Only incur `semigroups` and `void` dependencies on old GHCs.
* Add `holes1Of`.
* Add `locally` (https://github.com/ekmett/lens/pull/829).
* Add `ilocally` (https://github.com/ekmett/lens/pull/836).
* Add a third `Prism` law.
* Add `gplate1`.
* Add `Wrapped`/`Rewrapped` instances for `Data.Monoid.Ap`.
* Thu Aug 02 2018 psimons@suse.com
- Add lens at version 4.17.
/usr/lib/ghc-8.10.4/lens-5.0.1 /usr/lib/ghc-8.10.4/lens-5.0.1/libHSlens-5.0.1-AUVnivliGJaHZkpXUJIse1-ghc8.10.4.so /usr/share/licenses/ghc-lens /usr/share/licenses/ghc-lens/LICENSE
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