Control.Monad.Representable.Reader

Representable functors on Hask all monads, being isomorphic to a reader monad.

Representable functor monad

type Reader f = ReaderT f Identity

reader :: Representable f => (Key f -> b) -> Reader f b

runReader :: Indexable f => Reader f b -> Key f -> b

Monad Transformer

newtype ReaderT f m b

Constructors

ReaderT

Fields

getReaderT :: f (m b)

Instances

(Key f ~ e, Representable f, Monad m) => MonadReader e (ReaderT f m)

(Representable f, MonadWriter w m) => MonadWriter w (ReaderT f m)

Representable f => MonadTrans (ReaderT f)

(Representable f, Monad m) => Monad (ReaderT f m)

(Functor f, Functor m) => Functor (ReaderT f m)

(Representable f, Applicative m) => Applicative (ReaderT f m)

(Foldable f, Foldable m) => Foldable (ReaderT f m)

(Traversable f, Traversable m) => Traversable (ReaderT f m)

(Representable f, Representable m, Semigroup (Key f), Semigroup (Key m), Monoid (Key f), Monoid (Key m)) => Comonad (ReaderT f m)

(Representable f, Representable m, Semigroup (Key f), Semigroup (Key m)) => Extend (ReaderT f m)

(Representable f, Distributive m) => Distributive (ReaderT f m)

(Keyed f, Keyed m) => Keyed (ReaderT f m)

(Representable f, Representable m) => Zip (ReaderT f m)

(Representable f, Representable m) => ZipWithKey (ReaderT f m)

(Indexable f, Indexable m) => Indexable (ReaderT f m)

(Lookup f, Lookup m) => Lookup (ReaderT f m)

(Adjustable f, Adjustable m) => Adjustable (ReaderT f m)

(FoldableWithKey f, FoldableWithKey m) => FoldableWithKey (ReaderT f m)

(FoldableWithKey1 f, FoldableWithKey1 m) => FoldableWithKey1 (ReaderT f m)

(TraversableWithKey f, TraversableWithKey m) => TraversableWithKey (ReaderT f m)

(TraversableWithKey1 f, TraversableWithKey1 m) => TraversableWithKey1 (ReaderT f m)

(Representable f, MonadIO m) => MonadIO (ReaderT f m)

(Traversable1 f, Traversable1 m) => Traversable1 (ReaderT f m)

(Foldable1 f, Foldable1 m) => Foldable1 (ReaderT f m)

(Representable f, Apply m) => Apply (ReaderT f m)

(Representable f, Bind m) => Bind (ReaderT f m)

(Representable f, Representable m) => Representable (ReaderT f m)

ask :: MonadReader r m => m r

Retrieves the monad environment.

local

Arguments

:: MonadReader r m

=> forall a .

=> (r -> r)

The function to modify the environment.

-> m a

Reader to run in the modified environment.

-> m a

Executes a computation in a modified environment.

module Data.Functor.Representable