Control.Comonad.Env

The Env comonad (aka the Coreader, Environment, or Product comonad)

A co-Kleisli arrow in the Env comonad is isomorphic to a Kleisli arrow in the reader monad.

(a -> e -> m) ~ (a, e) -> m ~ Env e a -> m

ComonadEnv class

class Comonad w => ComonadEnv e w | w -> e where

Minimal complete definition

ask

Methods

ask :: w a -> e

Instances

ComonadEnv e (Arg e)

Methods

ask :: Arg e a -> e

ComonadEnv e ((,) e)

Methods

ask :: (e, a) -> e

(ComonadEnv e w, Monoid m) => ComonadEnv e (TracedT m w)

Methods

ask :: TracedT m w a -> e

ComonadEnv e w => ComonadEnv e (IdentityT * w)

Methods

ask :: IdentityT * w a -> e

ComonadEnv e w => ComonadEnv e (StoreT t w)

Methods

ask :: StoreT t w a -> e

Comonad w => ComonadEnv e (EnvT e w)

Methods

ask :: EnvT e w a -> e

asks :: ComonadEnv e w => (e -> e') -> w a -> e'

local :: (e -> e') -> EnvT e w a -> EnvT e' w a

Modifies the environment using the specified function.

The Env comonad

type Env e = EnvT e Identity

env :: e -> a -> Env e a

Create an Env using an environment and a value

runEnv :: Env e a -> (e, a)

The EnvT comonad transformer

data EnvT e w a

Constructors

EnvT e (w a)

Instances

Comonad w => ComonadEnv e (EnvT e w)

Methods

ask :: EnvT e w a -> e

ComonadStore s w => ComonadStore s (EnvT e w)

Methods

pos :: EnvT e w a -> s

peek :: s -> EnvT e w a -> a

peeks :: (s -> s) -> EnvT e w a -> a

seek :: s -> EnvT e w a -> EnvT e w a

seeks :: (s -> s) -> EnvT e w a -> EnvT e w a

experiment :: Functor f => (s -> f s) -> EnvT e w a -> f a

ComonadTraced m w => ComonadTraced m (EnvT e w)

Methods

trace :: m -> EnvT e w a -> a

ComonadHoist (EnvT e)

Methods

cohoist :: (Comonad w, Comonad v) => (forall x. w x -> v x) -> EnvT e w a -> EnvT e v a

ComonadTrans (EnvT e)

Methods

lower :: Comonad w => EnvT e w a -> w a

Functor w => Functor (EnvT e w)

Methods

fmap :: (a -> b) -> EnvT e w a -> EnvT e w b

(<$) :: a -> EnvT e w b -> EnvT e w a

(Monoid e, Applicative m) => Applicative (EnvT e m)

Methods

pure :: a -> EnvT e m a

(<*>) :: EnvT e m (a -> b) -> EnvT e m a -> EnvT e m b

(*>) :: EnvT e m a -> EnvT e m b -> EnvT e m b

(<*) :: EnvT e m a -> EnvT e m b -> EnvT e m a

Foldable w => Foldable (EnvT e w)

Methods

fold :: Monoid m => EnvT e w m -> m

foldMap :: Monoid m => (a -> m) -> EnvT e w a -> m

foldr :: (a -> b -> b) -> b -> EnvT e w a -> b

foldr' :: (a -> b -> b) -> b -> EnvT e w a -> b

foldl :: (b -> a -> b) -> b -> EnvT e w a -> b

foldl' :: (b -> a -> b) -> b -> EnvT e w a -> b

foldr1 :: (a -> a -> a) -> EnvT e w a -> a

foldl1 :: (a -> a -> a) -> EnvT e w a -> a

toList :: EnvT e w a -> [a]

null :: EnvT e w a -> Bool

length :: EnvT e w a -> Int

elem :: Eq a => a -> EnvT e w a -> Bool

maximum :: Ord a => EnvT e w a -> a

minimum :: Ord a => EnvT e w a -> a

sum :: Num a => EnvT e w a -> a

product :: Num a => EnvT e w a -> a

Traversable w => Traversable (EnvT e w)

Methods

traverse :: Applicative f => (a -> f b) -> EnvT e w a -> f (EnvT e w b)

sequenceA :: Applicative f => EnvT e w (f a) -> f (EnvT e w a)

mapM :: Monad m => (a -> m b) -> EnvT e w a -> m (EnvT e w b)

sequence :: Monad m => EnvT e w (m a) -> m (EnvT e w a)

(Semigroup e, ComonadApply w) => ComonadApply (EnvT e w)

Methods

(<@>) :: EnvT e w (a -> b) -> EnvT e w a -> EnvT e w b

(@>) :: EnvT e w a -> EnvT e w b -> EnvT e w b

(<@) :: EnvT e w a -> EnvT e w b -> EnvT e w a

Comonad w => Comonad (EnvT e w)

Methods

extract :: EnvT e w a -> a

duplicate :: EnvT e w a -> EnvT e w (EnvT e w a)

extend :: (EnvT e w a -> b) -> EnvT e w a -> EnvT e w b

(Data e, Typeable (* -> *) w, Data (w a), Data a) => Data (EnvT e w a)

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> EnvT e w a -> c (EnvT e w a)

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (EnvT e w a)

toConstr :: EnvT e w a -> Constr

dataTypeOf :: EnvT e w a -> DataType

dataCast1 :: Typeable (* -> *) t => (forall d. Data d => c (t d)) -> Maybe (c (EnvT e w a))

dataCast2 :: Typeable (* -> * -> *) t => (forall d b. (Data d, Data b) => c (t d b)) -> Maybe (c (EnvT e w a))

gmapT :: (forall b. Data b => b -> b) -> EnvT e w a -> EnvT e w a

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> EnvT e w a -> r

gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> EnvT e w a -> r

gmapQ :: (forall d. Data d => d -> u) -> EnvT e w a -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> EnvT e w a -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> EnvT e w a -> m (EnvT e w a)

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> EnvT e w a -> m (EnvT e w a)

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> EnvT e w a -> m (EnvT e w a)

runEnvT :: EnvT e w a -> (e, w a)

Re-exported modules

module Control.Comonad

module Control.Comonad.Trans.Class