Control.Monad.Readers

MonadState without the function dependency m -> s.

Documentation

module Control.Monad.Reader

class Monad m => MonadReaders r m where

Version of MonadReader modified to remove the functional dependency.

Minimal complete definition

local

Methods

ask :: m r

local :: (r -> r) -> m a -> m a

Instances

(Monad m, Monoid w, MonadReaders r m) => MonadReaders r (WriterT w m)

(Monad m, MonadReaders r m) => MonadReaders r (StateT s m)

Monad m => MonadReaders r (ReaderT r m)

asks

Arguments

:: MonadReaders r m

=> (r -> a)

The selector function to apply to the environment.

-> m a

Retrieves a function of the current environment.