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Control.Monad.Reader

Portability	non-portable ( mulit-param classes, functional dependencies )
Stability	experimental
Maintainer	libraries@haskell.org

Description

Declaration of the Monoid class,and instances for list and functions

Inspired by the paper Functional Programming with Overloading and Higher-Order Polymorphism, Mark P Jones (http://www.cse.ogi.edu/~mpj) Advanced School of Functional Programming, 1995.

class (Monad m) => MonadReader r m | m -> r where

Methods

ask :: m r

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

Instances

(MonadReader r' m) => MonadReader r' (ContT r m)

(Error e, MonadReader r m) => MonadReader r (ErrorT e m)

(MonadReader s m) => MonadReader s (ListT m)

(Monoid w) => MonadReader r (RWS r w s)

(Monoid w, Monad m) => MonadReader r (RWST r w s m)

MonadReader r ((->) r)

MonadReader r (Reader r)

(Monad m) => MonadReader r (ReaderT r m)

(MonadReader r m) => MonadReader r (StateT s m)

(Monoid w, MonadReader r m) => MonadReader r (WriterT w m)

asks :: (MonadReader r m) => (r -> a) -> m a

data Reader r a

Constructors

Reader

runReader :: (r -> a)

Instances

Functor (Reader r)

Monad (Reader r)

MonadFix (Reader r)

MonadReader r (Reader r)

runReader :: Reader r a -> r -> a

mapReader :: (a -> b) -> Reader r a -> Reader r b

withReader :: (r' -> r) -> Reader r a -> Reader r' a

data ReaderT r m a

Constructors

ReaderT

runReaderT :: (r -> m a)

Instances

(MonadCont m) => MonadCont (ReaderT r m)

(MonadError e m) => MonadError e (ReaderT r m)

(Monad m) => Functor (ReaderT r m)

(Monad m) => Monad (ReaderT r m)

(MonadPlus m) => MonadPlus (ReaderT r m)

(MonadFix m) => MonadFix (ReaderT r m)

(Monad m) => MonadReader r (ReaderT r m)

MonadTrans (ReaderT r)

(MonadIO m) => MonadIO (ReaderT r m)

(MonadState s m) => MonadState s (ReaderT r m)

(MonadWriter w m) => MonadWriter w (ReaderT r m)

runReaderT :: ReaderT r m a -> r -> m a

mapReaderT :: (m a -> n b) -> ReaderT w m a -> ReaderT w n b

withReaderT :: (r' -> r) -> ReaderT r m a -> ReaderT r' m a

module Control.Monad

module Control.Monad.Fix

module Control.Monad.Trans

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