Control.Comonad.Trans.Env.Lazy

The environment comonad transformer (aka coreader). This adds an extra value that can be accessed in the environment.

Left adjoint to the reader comonad.

The environment comonad

type Env e = EnvT e Identity

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

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

The environment comonad transformer

data EnvT e w a

Instances

ComonadTrans (EnvT e)

ComonadHoist (EnvT e)

Functor w => Functor (EnvT e w)

Comonad w => Comonad (EnvT e w)

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

Combinators

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