Control.Monad.Readers

MonadState without the function dependency m -> s.

Documentation

module Control.Monad.Reader

magnify' :: forall r s m b. MonadReaders s m => Getting r s r -> ReaderT r m b -> m b

I don't know why Control.Lens.magnify isn't working for me.

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

MonadReaders s (ReifiedFold s)

MonadReaders s (ReifiedGetter s)

(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.

view :: MonadReaders s m => Getting a s a -> m a

views :: (Profunctor p, MonadReaders s m) => Optical p (->) (Const r) s s a a -> p a r -> m r

iview :: MonadReaders s m => IndexedGetting i (i, a) s a -> m (i, a)

iviews :: MonadReaders s m => IndexedGetting i r s a -> (i -> a -> r) -> m r

preview :: MonadReaders s m => Getting (First a) s a -> m (Maybe a)

previews :: MonadReaders s m => Getting (First r) s a -> (a -> r) -> m (Maybe r)

ipreview :: MonadReaders s m => IndexedGetting i (First (i, a)) s a -> m (Maybe (i, a))

ipreviews :: MonadReaders s m => IndexedGetting i (First r) s a -> (i -> a -> r) -> m (Maybe r)

review :: MonadReaders b m => AReview t b -> m t

reviews :: MonadReaders b m => AReview t b -> (t -> r) -> m r

class (Magnified m ~ Magnified n, MonadReaders b m, MonadReaders a n) => Magnify m n b a | m -> b, n -> a, m a -> n, n b -> m where

Methods

magnify :: LensLike' (Magnified m c) a b -> m c -> n c