Copyright	(C) 2008-2014 Edward Kmett
License	BSD-style (see the file LICENSE)
Maintainer	Edward Kmett <ekmett@gmail.com>
Stability	experimental
Portability	non-portable (fundeps, MPTCs)
Safe Haskell	Safe
Language	Haskell2010

Control.Comonad.Env

Contents

ComonadEnv class
The Env comonad
The EnvT comonad transformer
Re-exported modules

Description

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

Synopsis

class Comonad w => ComonadEnv e w | w -> e where
- ask :: w a -> e
asks :: ComonadEnv e w => (e -> e') -> w a -> e'
local :: (e -> e') -> EnvT e w a -> EnvT e' w a
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)
runEnvT :: EnvT e w a -> (e, w a)
module Control.Comonad
module Control.Comonad.Trans.Class

ComonadEnv class

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

Methods

ask :: w a -> e Source #

Instances

Instances details

ComonadEnv e ( Arg e) Source #
Instance details Defined in Control.Comonad.Env.Class Methods ask :: Arg e a -> e Source #
ComonadEnv e ( (,) e) Source #
Instance details Defined in Control.Comonad.Env.Class Methods ask :: (e, a) -> e Source #
( ComonadEnv e w, Monoid m) => ComonadEnv e ( TracedT m w) Source #
Instance details Defined in Control.Comonad.Env.Class Methods ask :: TracedT m w a -> e Source #
ComonadEnv e w => ComonadEnv e ( IdentityT w) Source #
Instance details Defined in Control.Comonad.Env.Class Methods ask :: IdentityT w a -> e Source #
ComonadEnv e w => ComonadEnv e ( StoreT t w) Source #
Instance details Defined in Control.Comonad.Env.Class Methods ask :: StoreT t w a -> e Source #
Comonad w => ComonadEnv e ( EnvT e w) Source #
Instance details Defined in Control.Comonad.Env.Class Methods ask :: EnvT e w a -> e Source #

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

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

Modifies the environment using the specified function.

The Env comonad

type Env e = EnvT e Identity Source #

env :: e -> a -> Env e a Source #

Create an Env using an environment and a value

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

The EnvT comonad transformer

data EnvT e w a Source #

Constructors

EnvT e (w a)

Instances

Instances details

ComonadTraced m w => ComonadTraced m ( EnvT e w) Source #
Instance details Defined in Control.Comonad.Traced.Class Methods trace :: m -> EnvT e w a -> a Source #
ComonadStore s w => ComonadStore s ( EnvT e w) Source #
Instance details Defined in Control.Comonad.Store.Class Methods pos :: EnvT e w a -> s Source # peek :: s -> EnvT e w a -> a Source # peeks :: (s -> s) -> EnvT e w a -> a Source # seek :: s -> EnvT e w a -> EnvT e w a Source # seeks :: (s -> s) -> EnvT e w a -> EnvT e w a Source # experiment :: Functor f => (s -> f s) -> EnvT e w a -> f a Source #
Comonad w => ComonadEnv e ( EnvT e w) Source #
Instance details Defined in Control.Comonad.Env.Class Methods ask :: EnvT e w a -> e Source #
ComonadHoist ( EnvT e) Source #
Instance details Defined in Control.Comonad.Trans.Env Methods cohoist :: ( Comonad w, Comonad v) => ( forall x. w x -> v x) -> EnvT e w a -> EnvT e v a Source #
ComonadTrans ( EnvT e) Source #
Instance details Defined in Control.Comonad.Trans.Env Methods lower :: Comonad w => EnvT e w a -> w a Source #
Functor w => Functor ( EnvT e w) Source #
Instance details Defined in Control.Comonad.Trans.Env Methods fmap :: (a -> b) -> EnvT e w a -> EnvT e w b Source # (<$) :: a -> EnvT e w b -> EnvT e w a Source #
( Monoid e, Applicative m) => Applicative ( EnvT e m) Source #
Instance details Defined in Control.Comonad.Trans.Env Methods pure :: a -> EnvT e m a Source # (<>) :: EnvT e m (a -> b) -> EnvT e m a -> EnvT e m b Source # liftA2 :: (a -> b -> c) -> EnvT e m a -> EnvT e m b -> EnvT e m c Source # (>) :: EnvT e m a -> EnvT e m b -> EnvT e m b Source # (<*) :: EnvT e m a -> EnvT e m b -> EnvT e m a Source #
Foldable w => Foldable ( EnvT e w) Source #
Instance details Defined in Control.Comonad.Trans.Env Methods fold :: Monoid m => EnvT e w m -> m Source # foldMap :: Monoid m => (a -> m) -> EnvT e w a -> m Source # foldMap' :: Monoid m => (a -> m) -> EnvT e w a -> m Source # foldr :: (a -> b -> b) -> b -> EnvT e w a -> b Source # foldr' :: (a -> b -> b) -> b -> EnvT e w a -> b Source # foldl :: (b -> a -> b) -> b -> EnvT e w a -> b Source # foldl' :: (b -> a -> b) -> b -> EnvT e w a -> b Source # foldr1 :: (a -> a -> a) -> EnvT e w a -> a Source # foldl1 :: (a -> a -> a) -> EnvT e w a -> a Source # toList :: EnvT e w a -> [a] Source # null :: EnvT e w a -> Bool Source # length :: EnvT e w a -> Int Source # elem :: Eq a => a -> EnvT e w a -> Bool Source # maximum :: Ord a => EnvT e w a -> a Source # minimum :: Ord a => EnvT e w a -> a Source # sum :: Num a => EnvT e w a -> a Source # product :: Num a => EnvT e w a -> a Source #
Traversable w => Traversable ( EnvT e w) Source #
Instance details Defined in Control.Comonad.Trans.Env Methods traverse :: Applicative f => (a -> f b) -> EnvT e w a -> f ( EnvT e w b) Source # sequenceA :: Applicative f => EnvT e w (f a) -> f ( EnvT e w a) Source # mapM :: Monad m => (a -> m b) -> EnvT e w a -> m ( EnvT e w b) Source # sequence :: Monad m => EnvT e w (m a) -> m ( EnvT e w a) Source #
( Semigroup e, ComonadApply w) => ComonadApply ( EnvT e w) Source #
Instance details Defined in Control.Comonad.Trans.Env Methods (<@>) :: EnvT e w (a -> b) -> EnvT e w a -> EnvT e w b Source # (@>) :: EnvT e w a -> EnvT e w b -> EnvT e w b Source # (<@) :: EnvT e w a -> EnvT e w b -> EnvT e w a Source #
Comonad w => Comonad ( EnvT e w) Source #
Instance details Defined in Control.Comonad.Trans.Env Methods extract :: EnvT e w a -> a Source # duplicate :: EnvT e w a -> EnvT e w ( EnvT e w a) Source # extend :: ( EnvT e w a -> b) -> EnvT e w a -> EnvT e w b Source #
( Data e, Typeable w, Data (w a), Data a) => Data ( EnvT e w a) Source #
Instance details Defined in Control.Comonad.Trans.Env 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) Source # gunfold :: ( forall b r. Data b => c (b -> r) -> c r) -> ( forall r. r -> c r) -> Constr -> c ( EnvT e w a) Source # toConstr :: EnvT e w a -> Constr Source # dataTypeOf :: EnvT e w a -> DataType Source # dataCast1 :: Typeable t => ( forall d. Data d => c (t d)) -> Maybe (c ( EnvT e w a)) Source # dataCast2 :: Typeable t => ( forall d e0. ( Data d, Data e0) => c (t d e0)) -> Maybe (c ( EnvT e w a)) Source # gmapT :: ( forall b. Data b => b -> b) -> EnvT e w a -> EnvT e w a Source # gmapQl :: (r -> r' -> r) -> r -> ( forall d. Data d => d -> r') -> EnvT e w a -> r Source # gmapQr :: forall r r'. (r' -> r -> r) -> r -> ( forall d. Data d => d -> r') -> EnvT e w a -> r Source # gmapQ :: ( forall d. Data d => d -> u) -> EnvT e w a -> [u] Source # gmapQi :: Int -> ( forall d. Data d => d -> u) -> EnvT e w a -> u Source # gmapM :: Monad m => ( forall d. Data d => d -> m d) -> EnvT e w a -> m ( EnvT e w a) Source # gmapMp :: MonadPlus m => ( forall d. Data d => d -> m d) -> EnvT e w a -> m ( EnvT e w a) Source # gmapMo :: MonadPlus m => ( forall d. Data d => d -> m d) -> EnvT e w a -> m ( EnvT e w a) Source #

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

Re-exported modules

module Control.Comonad

module Control.Comonad.Trans.Class