comonad 0.5.0 → 0.6.0

raw patch · 2 files changed

+5/−62 lines, 2 filesdep −functor-apply

Dependencies removed: functor-apply

Files

• Control/Comonad.hs +4/−60
• comonad.cabal +1/−2

@@ -12,24 +12,18 @@ -- A 'Comonad' is the categorical dual of a 'Monad'. ---------------------------------------------------------------------------- module Control.Comonad ( -  -- * FunctorApply-    module Data.Functor.Apply   -- * Comonads-  , Comonad(..)-  , (=>=)     -- :: Comonad w => (w a -> b) -> (w b -> c) -> w a -> c-  , (=<=)     -- :: Comonad w => (w b -> c) -> (w a -> b) -> w a -> c+    Comonad(..)   , (=>>)     -- :: Comonad w => w a -> (w a -> b) -> w b   , (<<=)     -- :: Comonad w => (w a -> b) -> w a -> w b   , liftW     -- :: Comonad w => (a -> b) -> w a -> w b   , wfix      -- :: Comonad w => w (w a -> a) -> a -  -- * ComonadApply - strong lax symmetric semimonoidal comonads-  , ComonadApply-  , liftW2    -- :: ComonadApply w => (a -> b -> c) -> w a -> w b -> w c-  , liftW3    -- :: ComonadApply w => (a -> b -> c -> d) -> w a -> w b -> w c -> w d-   -- * Cokleisli Arrows   , Cokleisli(..)+  -- ** Cokleisli composition+  , (=>=)     -- :: Comonad w => (w a -> b) -> (w b -> c) -> w a -> c+  , (=<=)     -- :: Comonad w => (w b -> c) -> (w a -> b) -> w a -> c   ) where  import Prelude hiding (id, (.))@@ -37,7 +31,6 @@ import Control.Arrow import Control.Category import Control.Monad.Trans.Identity-import Data.Functor.Apply import Data.Functor.Identity import Data.Monoid @@ -169,48 +162,6 @@   extract = extract . runIdentityT   extend f (IdentityT m) = IdentityT (extend (f . IdentityT) m) -instance Comonad f => Comonad (MaybeApply f) where-  extract (MaybeApply (Right a)) = a-  extract (MaybeApply (Left fa)) = extract fa-  duplicate w@(MaybeApply Right{}) = MaybeApply (Right w)-  duplicate (MaybeApply (Left fa)) = MaybeApply (Left (extend (MaybeApply . Left) fa))--instance ComonadApply f => ComonadApply (MaybeApply f)-  -{- | --A strong lax symmetric semi-monoidal comonad. As such an instance of -'ComonadApply' is required to satisfy:--> extract (a <.> b) = extract a (extract b)--This class is based on ComonadZip from \"The Essence of Dataflow Programming\" -by Tarmo Uustalu and Varmo Vene, but adapted to fit the programming style of-Control.Applicative. 'Applicative' can be seen as a similar law over and above -FunctorApply that:--> pure (a b) = pure a <.> pure b---}--class (Comonad w, FunctorApply w) => ComonadApply w--- | Only requires a Semigroup, but no such class exists-instance Monoid m => ComonadApply ((,)m)--- | Only requires a Semigroup, but no such class exists-instance Monoid m => ComonadApply ((->)m)-instance ComonadApply Identity-instance ComonadApply w => ComonadApply (IdentityT w)---- | Lift a binary function into a comonad with zipping-liftW2 :: ComonadApply w => (a -> b -> c) -> w a -> w b -> w c-liftW2 = liftF2-{-# INLINE liftW2 #-}---- | Lift a ternary function into a comonad with zipping-liftW3 :: ComonadApply w => (a -> b -> c -> d) -> w a -> w b -> w c -> w d-liftW3 = liftF3-{-# INLINE liftW3 #-}- -- | The 'Cokleisli' 'Arrow's of a given 'Comonad' newtype Cokleisli w a b = Cokleisli { runCokleisli :: w a -> b } @@ -231,17 +182,10 @@ instance Comonad w => ArrowChoice (Cokleisli w) where   left = leftApp -instance ComonadApply w => ArrowLoop (Cokleisli w) where-  loop (Cokleisli f) = Cokleisli (fst . wfix . extend f') where -    f' wa wb = f ((,) <$> wa <.> (snd <$> wb))- -- Cokleisli arrows are actually just a special case of a reader monad:  instance Functor (Cokleisli w a) where   fmap f (Cokleisli g) = Cokleisli (f . g)--instance FunctorApply (Cokleisli w a) where-  Cokleisli f <.> Cokleisli a = Cokleisli (\w -> (f w) (a w))  instance Applicative (Cokleisli w a) where   pure = Cokleisli . const

@@ -1,6 +1,6 @@ name:          comonad category:      Control, Comonads-version:       0.5.0+version:       0.6.0 license:       BSD3 cabal-version: >= 1.2 license-file:  LICENSE@@ -16,7 +16,6 @@ library   build-depends:      base >= 4 && < 4.4,-    functor-apply >= 0.5 && < 0.6,     transformers >= 0.2.0 && < 0.3    exposed-modules: