transformers-0.1.4.0: Concrete monad transformersSource codeContentsIndex
Control.Monad.Trans.RWS.Lazy
Portabilityportable
Stabilityexperimental
Maintainerlibraries@haskell.org
Contents
The RWS monad
The RWST monad transformer
Reader operations
Writer operations
State operations
Lifting other operations
Description
Lazy RWS monad.
Synopsis
type RWS r w s = RWST r w s Identity
rws :: (r -> s -> (a, s, w)) -> RWS r w s a
runRWS :: RWS r w s a -> r -> s -> (a, s, w)
evalRWS :: RWS r w s a -> r -> s -> (a, w)
execRWS :: RWS r w s a -> r -> s -> (s, w)
mapRWS :: ((a, s, w) -> (b, s, w')) -> RWS r w s a -> RWS r w' s b
withRWS :: (r' -> s -> (r, s)) -> RWS r w s a -> RWS r' w s a
newtype RWST r w s m a = RWST {
runRWST :: r -> s -> m (a, s, w)
}
evalRWST :: Monad m => RWST r w s m a -> r -> s -> m (a, w)
execRWST :: Monad m => RWST r w s m a -> r -> s -> m (s, w)
mapRWST :: (m (a, s, w) -> n (b, s, w')) -> RWST r w s m a -> RWST r w' s n b
withRWST :: (r' -> s -> (r, s)) -> RWST r w s m a -> RWST r' w s m a
ask :: (Monoid w, Monad m) => RWST r w s m r
local :: (Monoid w, Monad m) => (r -> r) -> RWST r w s m a -> RWST r w s m a
asks :: (Monoid w, Monad m) => (r -> a) -> RWST r w s m a
tell :: (Monoid w, Monad m) => w -> RWST r w s m ()
listen :: (Monoid w, Monad m) => RWST r w s m a -> RWST r w s m (a, w)
pass :: (Monoid w, Monad m) => RWST r w s m (a, w -> w) -> RWST r w s m a
listens :: (Monoid w, Monad m) => (w -> b) -> RWST r w s m a -> RWST r w s m (a, b)
censor :: (Monoid w, Monad m) => (w -> w) -> RWST r w s m a -> RWST r w s m a
get :: (Monoid w, Monad m) => RWST r w s m s
put :: (Monoid w, Monad m) => s -> RWST r w s m ()
modify :: (Monoid w, Monad m) => (s -> s) -> RWST r w s m ()
gets :: (Monoid w, Monad m) => (s -> a) -> RWST r w s m a
liftCallCC :: Monoid w => ((((a, s, w) -> m (b, s, w)) -> m (a, s, w)) -> m (a, s, w)) -> ((a -> RWST r w s m b) -> RWST r w s m a) -> RWST r w s m a
liftCallCC' :: Monoid w => ((((a, s, w) -> m (b, s, w)) -> m (a, s, w)) -> m (a, s, w)) -> ((a -> RWST r w s m b) -> RWST r w s m a) -> RWST r w s m a
liftCatch :: (m (a, s, w) -> (e -> m (a, s, w)) -> m (a, s, w)) -> RWST l w s m a -> (e -> RWST l w s m a) -> RWST l w s m a
The RWS monad
type RWS r w s = RWST r w s IdentitySource
rws :: (r -> s -> (a, s, w)) -> RWS r w s aSource
runRWS :: RWS r w s a -> r -> s -> (a, s, w)Source
evalRWS :: RWS r w s a -> r -> s -> (a, w)Source
execRWS :: RWS r w s a -> r -> s -> (s, w)Source
mapRWS :: ((a, s, w) -> (b, s, w')) -> RWS r w s a -> RWS r w' s bSource
withRWS :: (r' -> s -> (r, s)) -> RWS r w s a -> RWS r' w s aSource
The RWST monad transformer
newtype RWST r w s m a Source
Constructors
RWST
runRWST :: r -> s -> m (a, s, w)
show/hide Instances
Monoid w => MonadTrans (RWST r w s)
(Monoid w, Monad m) => Monad (RWST r w s m)
Functor m => Functor (RWST r w s m)
(Monoid w, MonadFix m) => MonadFix (RWST r w s m)
(Monoid w, MonadPlus m) => MonadPlus (RWST r w s m)
(Monoid w, Functor m, Monad m) => Applicative (RWST r w s m)
(Monoid w, Functor m, MonadPlus m) => Alternative (RWST r w s m)
(Monoid w, MonadIO m) => MonadIO (RWST r w s m)
evalRWST :: Monad m => RWST r w s m a -> r -> s -> m (a, w)Source
execRWST :: Monad m => RWST r w s m a -> r -> s -> m (s, w)Source
mapRWST :: (m (a, s, w) -> n (b, s, w')) -> RWST r w s m a -> RWST r w' s n bSource
withRWST :: (r' -> s -> (r, s)) -> RWST r w s m a -> RWST r' w s m aSource
Reader operations
ask :: (Monoid w, Monad m) => RWST r w s m rSource
local :: (Monoid w, Monad m) => (r -> r) -> RWST r w s m a -> RWST r w s m aSource
asks :: (Monoid w, Monad m) => (r -> a) -> RWST r w s m aSource
Writer operations
tell :: (Monoid w, Monad m) => w -> RWST r w s m ()Source
listen :: (Monoid w, Monad m) => RWST r w s m a -> RWST r w s m (a, w)Source
pass :: (Monoid w, Monad m) => RWST r w s m (a, w -> w) -> RWST r w s m aSource
listens :: (Monoid w, Monad m) => (w -> b) -> RWST r w s m a -> RWST r w s m (a, b)Source
censor :: (Monoid w, Monad m) => (w -> w) -> RWST r w s m a -> RWST r w s m aSource
State operations
get :: (Monoid w, Monad m) => RWST r w s m sSource
put :: (Monoid w, Monad m) => s -> RWST r w s m ()Source
modify :: (Monoid w, Monad m) => (s -> s) -> RWST r w s m ()Source

Monadic state transformer.

Maps an old state to a new state inside a state monad. The old state is thrown away.

gets :: (Monoid w, Monad m) => (s -> a) -> RWST r w s m aSource
Gets specific component of the state, using a projection function supplied.
Lifting other operations
liftCallCC :: Monoid w => ((((a, s, w) -> m (b, s, w)) -> m (a, s, w)) -> m (a, s, w)) -> ((a -> RWST r w s m b) -> RWST r w s m a) -> RWST r w s m aSource
Uniform lifting of a callCC operation to the new monad. This version rolls back to the original state on entering the continuation.
liftCallCC' :: Monoid w => ((((a, s, w) -> m (b, s, w)) -> m (a, s, w)) -> m (a, s, w)) -> ((a -> RWST r w s m b) -> RWST r w s m a) -> RWST r w s m aSource
In-situ lifting of a callCC operation to the new monad. This version uses the current state on entering the continuation.
liftCatch :: (m (a, s, w) -> (e -> m (a, s, w)) -> m (a, s, w)) -> RWST l w s m a -> (e -> RWST l w s m a) -> RWST l w s m aSource
Lift a catchError operation to the new monad.
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