name: lens category: Data, Lenses version: 3.10.2 x-revision: 4 license: BSD3 cabal-version: >= 1.8 license-file: LICENSE author: Edward A. Kmett maintainer: Edward A. Kmett stability: provisional homepage: http://github.com/ekmett/lens/ bug-reports: http://github.com/ekmett/lens/issues copyright: Copyright (C) 2012-2013 Edward A. Kmett build-type: Custom tested-with: GHC == 7.6.3 synopsis: Lenses, Folds and Traversals description: 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 @README@: . A video on how to use lenses and how they are constructed is available from youtube: . Slides can be obtained here: . More information on the care and feeding of lenses, including a brief tutorial and motivation for their types can be found on the lens wiki: . A small game of @pong@ and other more complex examples that manage their state using lenses can be found in the example folder: . /Lenses, Folds and Traversals/ . With some signatures simplified, the core of the hierarchy of lens-like constructions looks like: . . <> . 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) . > -- baz :: 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). extra-source-files: .travis.yml .ghci .gitignore .vim.custom examples/LICENSE examples/lens-examples.cabal examples/*.hs examples/*.lhs examples/bf-examples/*.bf images/*.png travis/cabal-apt-install travis/config AUTHORS.markdown README.markdown CHANGELOG.markdown source-repository head type: git location: git://github.com/ekmett/lens.git -- Enable benchmarking against Neil Mitchell's uniplate library for comparative performance analysis. Defaults to being turned off to avoid -- the extra dependency. -- -- > cabal configure --enable-benchmarks -fbenchmark-uniplate && cabal build && cabal bench flag benchmark-uniplate default: False manual: True -- Generate inline pragmas when using template-haskell. This defaults to enabled, but you can -- -- > cabal install lens -f-inlining -- -- to shut it off to benchmark the relative performance impact, or as last ditch effort to address compile -- errors resulting from the myriad versions of template-haskell that all purport to be 2.8. flag inlining manual: True default: True -- Some 7.6.1-rc1 users report their TH still uses old style inline pragmas. This lets them turn on inlining. flag old-inline-pragmas default: False manual: True -- Make the test suites dump their template-haskell splices. flag dump-splices default: False manual: True -- You can disable the doctests test suite with -f-test-doctests flag test-doctests default: True manual: True -- You can disable the hunit test suite with -f-test-hunit flag test-hunit default: True manual: True -- Build the properties test if we're building tests flag test-properties default: True manual: True -- Disallow unsafeCoerce flag safe default: False manual: True -- Assert that we are trustworthy when we can flag trustworthy default: True manual: True flag lib-Werror default: False manual: True library -- x-revision 4: avoid clash with (,)-instances build-depends: base-orphans < 0.5 build-depends: array >= 0.3.0.2 && < 0.6, base >= 4.4 && < 4.7, bifunctors >= 4 && < 5, bytestring >= 0.9.1.10 && < 0.11, comonad >= 4 && < 5, contravariant >= 0.3 && < 1, containers >= 0.4.0 && < 0.6, distributive >= 0.3 && < 1, filepath >= 1.2.0.0 && < 1.4, generic-deriving >= 1.4 && < 1.7, ghc-prim, hashable >= 1.1.2.3 && < 1.3, MonadCatchIO-transformers >= 0.3 && < 0.3.1, mtl >= 2.0.1 && < 2.2, parallel >= 3.1.0.1 && < 3.3, profunctors >= 4 && < 5, reflection >= 1.1.6 && < 2, semigroupoids >= 4 && < 4.1, semigroups >= 0.8.4 && < 1, split >= 0.2 && < 0.3, tagged >= 0.4.4 && < 1, template-haskell >= 2.4 && < 2.10, text >= 0.11 && < 1.2, transformers >= 0.2 && < 0.4, transformers-compat >= 0.1 && < 1, unordered-containers >= 0.2 && < 0.3, vector >= 0.9 && < 0.11, void >= 0.5 && < 1 exposed-modules: Control.Exception.Lens Control.Lens Control.Lens.Action Control.Lens.At Control.Lens.Combinators Control.Lens.Cons Control.Lens.Each Control.Lens.Equality Control.Lens.Fold Control.Lens.Getter Control.Lens.Indexed Control.Lens.Internal Control.Lens.Internal.Action Control.Lens.Internal.Bazaar Control.Lens.Internal.ByteString Control.Lens.Internal.Context Control.Lens.Internal.Deque Control.Lens.Internal.Exception Control.Lens.Internal.Fold Control.Lens.Internal.Getter Control.Lens.Internal.Indexed Control.Lens.Internal.Instances Control.Lens.Internal.Iso Control.Lens.Internal.Level Control.Lens.Internal.Magma Control.Lens.Internal.Prism Control.Lens.Internal.Review Control.Lens.Internal.Setter Control.Lens.Internal.Zipper Control.Lens.Internal.Zoom Control.Lens.Iso Control.Lens.Lens Control.Lens.Level Control.Lens.Loupe Control.Lens.Operators Control.Lens.Plated Control.Lens.Prism Control.Lens.Reified Control.Lens.Review Control.Lens.Setter Control.Lens.Simple Control.Lens.TH Control.Lens.Traversal Control.Lens.Tuple Control.Lens.Type Control.Lens.Wrapped Control.Lens.Zipper Control.Lens.Zoom Control.Monad.Error.Lens Control.Parallel.Strategies.Lens Control.Seq.Lens Data.Array.Lens Data.Bits.Lens Data.ByteString.Lens Data.ByteString.Strict.Lens Data.ByteString.Lazy.Lens Data.Complex.Lens Data.Data.Lens Data.Dynamic.Lens Data.HashSet.Lens Data.IntSet.Lens Data.List.Lens Data.List.Split.Lens Data.Sequence.Lens Data.Set.Lens Data.Text.Lens Data.Text.Strict.Lens Data.Text.Lazy.Lens Data.Tree.Lens Data.Typeable.Lens Data.Vector.Lens Data.Vector.Generic.Lens Generics.Deriving.Lens GHC.Generics.Lens System.Exit.Lens System.FilePath.Lens System.IO.Error.Lens Language.Haskell.TH.Lens Numeric.Lens if flag(safe) cpp-options: -DSAFE=1 if flag(trustworthy) && impl(ghc>=7.2) other-extensions: Trustworthy cpp-options: -DTRUSTWORTHY=1 if flag(old-inline-pragmas) && impl(ghc>=7.6.0.20120810) cpp-options: -DOLD_INLINE_PRAGMAS=1 if flag(inlining) cpp-options: -DINLINING if flag(lib-Werror) ghc-options: -Werror if impl(ghc<7.4) ghc-options: -fno-spec-constr-count if impl(ghc>=7.2) cpp-options: -DDEFAULT_SIGNATURES=1 ghc-options: -Wall -fwarn-tabs -O2 -fdicts-cheap -funbox-strict-fields -fmax-simplifier-iterations=10 hs-source-dirs: src -- Verify that Template Haskell expansion works test-suite templates type: exitcode-stdio-1.0 main-is: templates.hs build-depends: base, lens ghc-options: -Wall -threaded hs-source-dirs: tests if flag(dump-splices) ghc-options: -ddump-splices if impl(ghc<7.6.1) ghc-options: -Werror -- Verify the properties of lenses with QuickCheck test-suite properties type: exitcode-stdio-1.0 main-is: properties.hs ghc-options: -w -threaded -rtsopts -with-rtsopts=-N hs-source-dirs: tests if !flag(test-properties) buildable: False else build-depends: base, lens, QuickCheck >= 2.4, test-framework >= 0.6, test-framework-quickcheck2 >= 0.2, test-framework-th >= 0.2, transformers test-suite hunit type: exitcode-stdio-1.0 main-is: hunit.hs ghc-options: -w -threaded -rtsopts -with-rtsopts=-N hs-source-dirs: tests if !flag(test-hunit) buildable: False else build-depends: base, containers, HUnit >= 1.2, lens, mtl, test-framework >= 0.6, test-framework-hunit >= 0.2, test-framework-th >= 0.2 -- Verify the results of the examples test-suite doctests type: exitcode-stdio-1.0 main-is: doctests.hs ghc-options: -Wall -threaded hs-source-dirs: tests if !flag(test-doctests) buildable: False else build-depends: base, bytestring, containers, directory >= 1.0, deepseq, doctest >= 0.9.1, filepath, generic-deriving, mtl, nats, parallel, semigroups >= 0.9, simple-reflect >= 0.3.1, split, text, unordered-containers, vector if impl(ghc<7.6.1) ghc-options: -Werror -- Basic benchmarks for the uniplate-style combinators benchmark plated type: exitcode-stdio-1.0 main-is: plated.hs ghc-options: -Wall -O2 -threaded -fdicts-cheap -funbox-strict-fields hs-source-dirs: benchmarks build-depends: base, comonad, criterion, deepseq, generic-deriving, lens, transformers if flag(benchmark-uniplate) build-depends: uniplate >= 1.6.7 && < 1.7 cpp-options: -DBENCHMARK_UNIPLATE -- Benchmarking alongside variants benchmark alongside type: exitcode-stdio-1.0 main-is: alongside.hs ghc-options: -w -O2 -threaded -fdicts-cheap -funbox-strict-fields hs-source-dirs: benchmarks build-depends: base, comonad, comonads-fd, criterion, deepseq, lens, transformers -- Benchmarking unsafe implementation strategies benchmark unsafe type: exitcode-stdio-1.0 main-is: unsafe.hs ghc-options: -w -O2 -threaded -fdicts-cheap -funbox-strict-fields hs-source-dirs: benchmarks build-depends: base, comonad, comonads-fd, criterion, deepseq, generic-deriving, lens, transformers -- Benchmarking zipper usage benchmark zipper type: exitcode-stdio-1.0 main-is: zipper.hs ghc-options: -w -O2 -threaded -fdicts-cheap -funbox-strict-fields hs-source-dirs: benchmarks build-depends: base, comonad, comonads-fd, criterion, deepseq, generic-deriving, lens, transformers