-- Hoogle documentation, generated by Haddock -- See Hoogle, http://www.haskell.org/hoogle/ -- | Comonad transformers -- -- Comonad transformers @package comonad-transformers @version 3.0 module Data.Functor.Composition -- | We often need to distinguish between various forms of Functor-like -- composition in Haskell in order to please the type system. This lets -- us work with these representations uniformly. class Composition o decompose :: Composition o => o f g x -> f (g x) compose :: Composition o => f (g x) -> o f g x instance Composition Compose module Data.Functor.Coproduct newtype Coproduct f g a Coproduct :: Either (f a) (g a) -> Coproduct f g a getCoproduct :: Coproduct f g a -> Either (f a) (g a) left :: f a -> Coproduct f g a right :: g a -> Coproduct f g a coproduct :: (f a -> b) -> (g a -> b) -> Coproduct f g a -> b instance (Contravariant f, Contravariant g) => Contravariant (Coproduct f g) instance (Comonad f, Comonad g) => Comonad (Coproduct f g) instance (Extend f, Extend g) => Extend (Coproduct f g) instance (Traversable1 f, Traversable1 g) => Traversable1 (Coproduct f g) instance (Traversable f, Traversable g) => Traversable (Coproduct f g) instance (Foldable1 f, Foldable1 g) => Foldable1 (Coproduct f g) instance (Foldable f, Foldable g) => Foldable (Coproduct f g) instance (Functor f, Functor g) => Functor (Coproduct f g) module Control.Comonad.Trans.Identity -- | The trivial monad transformer, which maps a monad to an equivalent -- monad. newtype IdentityT (m :: * -> *) a :: (* -> *) -> * -> * IdentityT :: m a -> IdentityT a runIdentityT :: IdentityT a -> m a module Control.Comonad.Trans.Class class ComonadTrans t lower :: (ComonadTrans t, Comonad w) => t w a -> w a instance ComonadTrans IdentityT module Control.Comonad.Hoist.Class class ComonadHoist t cohoist :: (ComonadHoist t, Comonad w) => t w a -> t Identity a instance ComonadHoist IdentityT -- | The environment comonad transformer (aka coreader). This adds an extra -- value that can be accessed in the environment. -- -- Left adjoint to the reader comonad. module Control.Comonad.Trans.Env type Env e = EnvT e Identity env :: e -> a -> Env e a runEnv :: Env e a -> (e, a) data EnvT e w a EnvT :: e -> (w a) -> EnvT e w a runEnvT :: EnvT e w a -> (e, w a) lowerEnvT :: EnvT e w a -> w a ask :: EnvT e w a -> e asks :: (e -> f) -> EnvT e w a -> f local :: (e -> e) -> EnvT e w a -> EnvT e w a instance Traversable w => Traversable (EnvT e w) instance Foldable w => Foldable (EnvT e w) instance (Semigroup e, ComonadApply w) => ComonadApply (EnvT e w) instance (Semigroup e, Apply w) => Apply (EnvT e w) instance ComonadHoist (EnvT e) instance ComonadTrans (EnvT e) instance Comonad w => Comonad (EnvT e w) instance Extend w => Extend (EnvT e w) instance Functor w => Functor (EnvT e w) instance (Data e, Typeable1 w, Data (w a), Data a) => Data (EnvT e w a) instance (Typeable s, Typeable1 w, Typeable a) => Typeable (EnvT s w a) instance (Typeable s, Typeable1 w) => Typeable1 (EnvT s w) -- | The strict store (state-in-context/costate) comonad transformer is -- subject to the laws: -- --
--   x = seek (pos x) x
--   y = pos (seek y x)
--   seek y x = seek y (seek z x)
--   
-- -- Thanks go to Russell O'Connor and Daniel Peebles for their help -- formulating and proving the laws for this comonad transformer. module Control.Comonad.Trans.Store type Store s = StoreT s Identity store :: (s -> a) -> s -> Store s a runStore :: Store s a -> (s -> a, s) data StoreT s w a StoreT :: (w (s -> a)) -> s -> StoreT s w a runStoreT :: StoreT s w a -> (w (s -> a), s) -- | Read the current position pos :: StoreT s w a -> s -- | Seek to an absolute location -- --
--   seek s = peek s . duplicate
--   
seek :: Comonad w => s -> StoreT s w a -> StoreT s w a -- | Seek to a relative location -- --
--   seeks f = peeks f . duplicate
--   
seeks :: Comonad w => (s -> s) -> StoreT s w a -> StoreT s w a -- | Peek at a value at a given absolute location -- --
--   peek x . extend (peek y) = peek y
--   
peek :: Comonad w => s -> StoreT s w a -> a -- | Peek at a value at a given relative location peeks :: Comonad w => (s -> s) -> StoreT s w a -> a experiment :: (Comonad w, Functor f) => (s -> f s) -> StoreT s w a -> f a instance ComonadHoist (StoreT s) instance ComonadTrans (StoreT s) instance Comonad w => Comonad (StoreT s w) instance Extend w => Extend (StoreT s w) instance (Applicative w, Monoid s) => Applicative (StoreT s w) instance (ComonadApply w, Semigroup s) => ComonadApply (StoreT s w) instance (Apply w, Semigroup s) => Apply (StoreT s w) instance Functor w => Functor (StoreT s w) instance (Typeable s, Typeable1 w, Typeable a) => Typeable (StoreT s w a) instance (Typeable s, Typeable1 w) => Typeable1 (StoreT s w) -- | The trace comonad transformer (aka the cowriter or exponential comonad -- transformer). module Control.Comonad.Trans.Traced type Traced m = TracedT m Identity traced :: (m -> a) -> Traced m a runTraced :: Traced m a -> m -> a newtype TracedT m w a TracedT :: w (m -> a) -> TracedT m w a runTracedT :: TracedT m w a -> w (m -> a) trace :: Comonad w => m -> TracedT m w a -> a listen :: Functor w => TracedT m w a -> TracedT m w (a, m) listens :: Functor w => (m -> b) -> TracedT m w a -> TracedT m w (a, b) censor :: Functor w => (m -> m) -> TracedT m w a -> TracedT m w a instance (Typeable s, Typeable1 w) => Typeable1 (TracedT s w) instance Distributive w => Distributive (TracedT m w) instance Monoid m => ComonadHoist (TracedT m) instance Monoid m => ComonadTrans (TracedT m) instance (Comonad w, Monoid m) => Comonad (TracedT m w) instance (Extend w, Semigroup m) => Extend (TracedT m w) instance Applicative w => Applicative (TracedT m w) instance (ComonadApply w, Monoid m) => ComonadApply (TracedT m w) instance Apply w => Apply (TracedT m w) instance Functor w => Functor (TracedT m w)