Control.Comonad.Trans.Env

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

Left adjoint to the reader comonad.

Documentation

type Env e = EnvT e Identity

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

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

data EnvT e w a

Constructors

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)

ask :: EnvT e w a -> e