Control.Monad.State

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

Description

State monads.

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) => MonadState s m | m -> s where

Methods

get :: m s

put :: s -> m ()

Instances

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

(Error e, MonadState s m) => MonadState s (ErrorT e m)

(MonadState s m) => MonadState s (ListT m)

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

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

MonadState s (State s)

(Monad m) => MonadState s (StateT s m)

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

(Monoid w, MonadState s m) => MonadState s (WriterT w m)

modify :: (MonadState s m) => (s -> s) -> m ()

gets :: (MonadState s m) => (s -> a) -> m a

data State s a

Constructors

State

runState :: (s -> (a, s))

Instances

Functor (State s)

Monad (State s)

MonadFix (State s)

MonadState s (State s)

runState :: State s a -> s -> (a, s)

evalState :: State s a -> s -> a

execState :: State s a -> s -> s

mapState :: ((a, s) -> (b, s)) -> State s a -> State s b

withState :: (s -> s) -> State s a -> State s a

data StateT s m a

Constructors

StateT

runStateT :: (s -> m (a, s))

Instances

(MonadCont m) => MonadCont (StateT s m)

(MonadError e m) => MonadError e (StateT s m)

(Monad m) => Functor (StateT s m)

(Monad m) => Monad (StateT s m)

(MonadPlus m) => MonadPlus (StateT s m)

(MonadFix m) => MonadFix (StateT s m)

(Monad m) => MonadState s (StateT s m)

MonadTrans (StateT s)

(MonadIO m) => MonadIO (StateT s m)

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

(MonadWriter w m) => MonadWriter w (StateT s m)

runStateT :: StateT s m a -> s -> m (a, s)

evalStateT :: (Monad m) => StateT s m a -> s -> m a

execStateT :: (Monad m) => StateT s m a -> s -> m s

mapStateT :: (m (a, s) -> n (b, s)) -> StateT s m a -> StateT s n b

withStateT :: (s -> s) -> StateT s m a -> StateT s m a

module Control.Monad

module Control.Monad.Fix

module Control.Monad.Trans

Produced by Haddock version 0.4