name: semigroupoids category: Control, Comonads version: 4.5 license: BSD3 cabal-version: >= 1.8 license-file: LICENSE author: Edward A. Kmett maintainer: Edward A. Kmett stability: provisional homepage: http://github.com/ekmett/semigroupoids bug-reports: http://github.com/ekmett/semigroupoids/issues copyright: Copyright (C) 2011-2015 Edward A. Kmett build-type: Custom synopsis: Semigroupoids: Category sans id extra-source-files: .ghci .travis.yml .gitignore .vim.custom description: Provides a wide array of (semi)groupoids and operations for working with them. . A 'Semigroupoid' is a 'Category' without the requirement of identity arrows for every object in the category. . A 'Category' is any 'Semigroupoid' for which the Yoneda lemma holds. . When working with comonads you often have the @\<*\>@ portion of an @Applicative@, but not the @pure@. This was captured in Uustalu and Vene's \"Essence of Dataflow Programming\" in the form of the @ComonadZip@ class in the days before @Applicative@. Apply provides a weaker invariant, but for the comonads used for data flow programming (found in the streams package), this invariant is preserved. Applicative function composition forms a semigroupoid. . Similarly many structures are nearly a comonad, but not quite, for instance lists provide a reasonable 'extend' operation in the form of 'tails', but do not always contain a value. . Ideally the following relationships would hold: . > Foldable ----> Traversable <--- Functor ------> Alt ---------> Plus Semigroupoid > | | | | | > v v v v v > Foldable1 ---> Traversable1 Apply --------> Applicative -> Alternative Category > | | | | > v v v v > Bind ---------> Monad -------> MonadPlus Arrow > . Apply, Bind, and Extend (not shown) give rise the Static, Kleisli and Cokleisli semigroupoids respectively. . This lets us remove many of the restrictions from various monad transformers as in many cases the binding operation or @\<*\>@ operation does not require them. . Finally, to work with these weaker structures it is beneficial to have containers that can provide stronger guarantees about their contents, so versions of 'Traversable' and 'Foldable' that can be folded with just a 'Semigroup' are added. source-repository head type: git location: git://github.com/ekmett/semigroupoids.git flag containers description: You can disable the use of the `containers` package using `-f-containers`. . Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. default: True manual: True flag contravariant description: You can disable the use of the `contravariant` package using `-f-contravariant`. . Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. . If disabled we will not supply instances of `Contravariant` . default: True manual: True flag distributive description: You can disable the use of the `distributive` package using `-f-distributive`. . Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. . If disabled we will not supply instances of `Distributive` . default: True manual: True flag doctests description: You can disable testing with doctests using `-f-doctests`. default: True manual: True flag comonad description: You can disable the use of the `comonad` package using `-f-comonad`. . Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. . If disabled we will not supply instances of `Comonad` . default: True manual: True library build-depends: base >= 4.6 && < 5, base-orphans >= 0.3 && < 1, semigroups >= 0.8.3.1 && < 1, transformers >= 0.2 && < 0.6, transformers-compat >= 0.3 && < 0.5 if flag(containers) build-depends: containers >= 0.3 && < 0.6 if flag(contravariant) build-depends: contravariant >= 0.2.0.1 && < 2 if flag(distributive) build-depends: distributive >= 0.2.2 && < 1 if flag(comonad) build-depends: comonad >= 4 && < 5 hs-source-dirs: src exposed-modules: Data.Functor.Alt Data.Functor.Apply Data.Functor.Bind Data.Functor.Bind.Trans Data.Functor.Extend Data.Functor.Plus Data.Groupoid Data.Isomorphism Data.Semifunctor Data.Semifunctor.Associative Data.Semifunctor.Braided Data.Semigroup.Foldable Data.Semigroup.Traversable Data.Semigroupoid Data.Semigroupoid.Coproduct Data.Semigroupoid.Dual Data.Semigroupoid.Ob Data.Semigroupoid.Product Data.Semigroupoid.Static Data.Traversable.Instances ghc-options: -Wall -fno-warn-warnings-deprecations test-suite doctests type: exitcode-stdio-1.0 main-is: doctests.hs hs-source-dirs: test ghc-options: -Wall -fno-warn-warnings-deprecations if !flag(doctests) buildable: False else build-depends: base >= 4.6 && < 5, doctest >= 0.9.1 && < 0.10, directory >= 1.0, filepath