Safe Haskell	Safe-Inferred
Language	Haskell2010

Data.Automaton.Trans.RWS

Description

This module combines the wrapping and running functions for the Reader, Writer and State monad layers in a single layer.

It is based on the strict RWS monad Strict, so when combining it with other modules such as mtl's, the strict version has to be included, i.e. Strict instead of RWS or Lazy.

Synopsis

rwsS :: (Functor m, Monad m, Monoid w) => Automaton m (r, s, a) (w, s, b) -> Automaton (RWST r w s m) a b
runRWSS :: (Functor m, Monad m, Monoid w) => Automaton (RWST r w s m) a b -> Automaton m (r, s, a) (w, s, b)
newtype RWST r w s (m :: Type -> Type) a = RWST {
- runRWST :: r -> s -> m (a, s, w)
}
type RWS r w s = RWST r w s Identity
liftCallCC' :: Monoid w => CallCC m (a, s, w) (b, s, w) -> CallCC (RWST r w s m) a b
get :: forall w (m :: Type -> Type) r s. (Monoid w, Monad m) => RWST r w s m s
tell :: forall (m :: Type -> Type) w r s. Monad m => w -> RWST r w s m ()
put :: forall w (m :: Type -> Type) s r. (Monoid w, Monad m) => s -> RWST r w s m ()
ask :: forall w (m :: Type -> Type) r s. (Monoid w, Monad m) => RWST r w s m r
asks :: forall w (m :: Type -> Type) r a s. (Monoid w, Monad m) => (r -> a) -> RWST r w s m a
local :: forall r w s (m :: Type -> Type) a. (r -> r) -> RWST r w s m a -> RWST r w s m a
listen :: forall (m :: Type -> Type) r w s a. Monad m => RWST r w s m a -> RWST r w s m (a, w)
listens :: forall (m :: Type -> Type) w b r s a. Monad m => (w -> b) -> RWST r w s m a -> RWST r w s m (a, b)
censor :: forall (m :: Type -> Type) w r s a. Monad m => (w -> w) -> RWST r w s m a -> RWST r w s m a
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
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 :: forall r' s r w (m :: Type -> Type) a. (r' -> s -> (r, s)) -> RWST r w s m a -> RWST r' w s m a
reader :: forall w (m :: Type -> Type) r a s. (Monoid w, Monad m) => (r -> a) -> RWST r w s m a
state :: forall w (m :: Type -> Type) s a r. (Monoid w, Monad m) => (s -> (a, s)) -> RWST r w s m a
modify :: forall w (m :: Type -> Type) s r. (Monoid w, Monad m) => (s -> s) -> RWST r w s m ()
gets :: forall w (m :: Type -> Type) s a r. (Monoid w, Monad m) => (s -> a) -> RWST r w s m a
writer :: forall (m :: Type -> Type) a w r s. Monad m => (a, w) -> RWST r w s m a
pass :: forall (m :: Type -> Type) r w s a. Monad m => RWST r w s m (a, w -> w) -> RWST r w s m a

Documentation

rwsS :: (Functor m, Monad m, Monoid w) => Automaton m (r, s, a) (w, s, b) -> Automaton (RWST r w s m) a b Source #

Wrap an Automaton with explicit state variables in RWST monad transformer.

runRWSS :: (Functor m, Monad m, Monoid w) => Automaton (RWST r w s m) a b -> Automaton m (r, s, a) (w, s, b) Source #

Run the RWST layer by making the state variables explicit.

newtype RWST r w s (m :: Type -> Type) a #

A monad transformer adding reading an environment of type r, collecting an output of type w and updating a state of type s to an inner monad m.

Constructors

RWST
Fields runRWST :: r -> s -> m (a, s, w)

Instances

Instances details

MFunctor (RWST r w s :: (Type -> Type) -> Type -> Type)
Instance details Defined in Control.Monad.Morph Methods hoist :: forall m n (b :: k). Monad m => (forall a. m a -> n a) -> RWST r w s m b -> RWST r w s n b #
(Monoid w, MonadSplit g m) => MonadSplit g (RWST r w s m)
Instance details Defined in Control.Monad.Random.Class Methods getSplit :: RWST r w s m g #
Monoid w => MonadTrans (RWST r w s)
Instance details Defined in Control.Monad.Trans.RWS.Strict Methods lift :: Monad m => m a -> RWST r w s m a #
(Monoid w, MonadInterleave m) => MonadInterleave (RWST r w s m)
Instance details Defined in Control.Monad.Random.Class Methods interleave :: RWST r w s m a -> RWST r w s m a #
(Monoid w, MonadRandom m) => MonadRandom (RWST r w s m)
Instance details Defined in Control.Monad.Random.Class Methods getRandomR :: Random a => (a, a) -> RWST r w s m a # getRandom :: Random a => RWST r w s m a # getRandomRs :: Random a => (a, a) -> RWST r w s m [a] # getRandoms :: Random a => RWST r w s m [a] #
(Monoid w, MonadFail m) => MonadFail (RWST r w s m)
Instance details Defined in Control.Monad.Trans.RWS.Strict Methods fail :: String -> RWST r w s m a #
(Monoid w, MonadFix m) => MonadFix (RWST r w s m)
Instance details Defined in Control.Monad.Trans.RWS.Strict Methods mfix :: (a -> RWST r w s m a) -> RWST r w s m a #
(Monoid w, MonadIO m) => MonadIO (RWST r w s m)
Instance details Defined in Control.Monad.Trans.RWS.Strict Methods liftIO :: IO a -> RWST r w s m a #
Contravariant m => Contravariant (RWST r w s m)
Instance details Defined in Control.Monad.Trans.RWS.Strict Methods contramap :: (a' -> a) -> RWST r w s m a -> RWST r w s m a' # (>$) :: b -> RWST r w s m b -> RWST r w s m a #
(Monoid w, Functor m, MonadPlus m) => Alternative (RWST r w s m)
Instance details Defined in Control.Monad.Trans.RWS.Strict Methods empty :: RWST r w s m a # (<\|>) :: RWST r w s m a -> RWST r w s m a -> RWST r w s m a # some :: RWST r w s m a -> RWST r w s m [a] # many :: RWST r w s m a -> RWST r w s m [a] #
(Monoid w, Functor m, Monad m) => Applicative (RWST r w s m)
Instance details Defined in Control.Monad.Trans.RWS.Strict Methods pure :: a -> RWST r w s m a # (<>) :: RWST r w s m (a -> b) -> RWST r w s m a -> RWST r w s m b # liftA2 :: (a -> b -> c) -> RWST r w s m a -> RWST r w s m b -> RWST r w s m c # (>) :: RWST r w s m a -> RWST r w s m b -> RWST r w s m b # (<*) :: RWST r w s m a -> RWST r w s m b -> RWST r w s m a #
Functor m => Functor (RWST r w s m)
Instance details Defined in Control.Monad.Trans.RWS.Strict Methods fmap :: (a -> b) -> RWST r w s m a -> RWST r w s m b # (<$) :: a -> RWST r w s m b -> RWST r w s m a #
(Monoid w, Monad m) => Monad (RWST r w s m)
Instance details Defined in Control.Monad.Trans.RWS.Strict Methods (>>=) :: RWST r w s m a -> (a -> RWST r w s m b) -> RWST r w s m b # (>>) :: RWST r w s m a -> RWST r w s m b -> RWST r w s m b # return :: a -> RWST r w s m a #
(Monoid w, MonadPlus m) => MonadPlus (RWST r w s m)
Instance details Defined in Control.Monad.Trans.RWS.Strict Methods mzero :: RWST r w s m a # mplus :: RWST r w s m a -> RWST r w s m a -> RWST r w s m a #
(Monoid w, PrimMonad m) => PrimMonad (RWST r w s m)
Instance details Defined in Control.Monad.Primitive Associated Types type PrimState (RWST r w s m) # Methods primitive :: (State# (PrimState (RWST r w s m)) -> (# State# (PrimState (RWST r w s m)), a #)) -> RWST r w s m a #
(Monoid w, Monad m) => Selective (RWST r w s m)
Instance details Defined in Control.Selective Methods select :: RWST r w s m (Either a b) -> RWST r w s m (a -> b) -> RWST r w s m b #
Generic (RWST r w s m a)
Instance details Defined in Control.Monad.Trans.RWS.Strict Associated Types type Rep (RWST r w s m a) :: Type -> Type # Methods from :: RWST r w s m a -> Rep (RWST r w s m a) x # to :: Rep (RWST r w s m a) x -> RWST r w s m a #
type PrimState (RWST r w s m)
Instance details Defined in Control.Monad.Primitive type PrimState (RWST r w s m) = PrimState m
type Rep (RWST r w s m a)
Instance details Defined in Control.Monad.Trans.RWS.Strict type Rep (RWST r w s m a) = D1 ('MetaData "RWST" "Control.Monad.Trans.RWS.Strict" "transformers-0.6.1.0" 'True) (C1 ('MetaCons "RWST" 'PrefixI 'True) (S1 ('MetaSel ('Just "runRWST") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (r -> s -> m (a, s, w)))))

type RWS r w s = RWST r w s Identity #

A monad containing an environment of type r, output of type w and an updatable state of type s.

liftCallCC' :: Monoid w => CallCC m (a, s, w) (b, s, w) -> CallCC (RWST r w s m) a b #

In-situ lifting of a callCC operation to the new monad. This version uses the current state on entering the continuation.

get :: forall w (m :: Type -> Type) r s. (Monoid w, Monad m) => RWST r w s m s #

Fetch the current value of the state within the monad.

tell :: forall (m :: Type -> Type) w r s. Monad m => w -> RWST r w s m () #

tell w is an action that produces the output w.

put :: forall w (m :: Type -> Type) s r. (Monoid w, Monad m) => s -> RWST r w s m () #

put s sets the state within the monad to s.

ask :: forall w (m :: Type -> Type) r s. (Monoid w, Monad m) => RWST r w s m r #

Fetch the value of the environment.

asks :: forall w (m :: Type -> Type) r a s. (Monoid w, Monad m) => (r -> a) -> RWST r w s m a #

Retrieve a function of the current environment.

```
asks f = liftM f ask
```

local :: forall r w s (m :: Type -> Type) a. (r -> r) -> RWST r w s m a -> RWST r w s m a #

Execute a computation in a modified environment

runRWST (local f m) r s = runRWST m (f r) s

listen :: forall (m :: Type -> Type) r w s a. Monad m => RWST r w s m a -> RWST r w s m (a, w) #

listen m is an action that executes the action m and adds its output to the value of the computation.

runRWST (listen m) r s = liftM (\ (a, w) -> ((a, w), w)) (runRWST m r s)

listens :: forall (m :: Type -> Type) w b r s a. Monad m => (w -> b) -> RWST r w s m a -> RWST r w s m (a, b) #

listens f m is an action that executes the action m and adds the result of applying f to the output to the value of the computation.

listens f m = liftM (id *** f) (listen m)

runRWST (listens f m) r s = liftM (\ (a, w) -> ((a, f w), w)) (runRWST m r s)

censor :: forall (m :: Type -> Type) w r s a. Monad m => (w -> w) -> RWST r w s m a -> RWST r w s m a #

censor f m is an action that executes the action m and applies the function f to its output, leaving the return value unchanged.

censor f m = pass (liftM (\ x -> (x,f)) m)

runRWST (censor f m) r s = liftM (\ (a, w) -> (a, f w)) (runRWST m r s)

rws :: (r -> s -> (a, s, w)) -> RWS r w s a #

Construct an RWS computation from a function. (The inverse of runRWS.)

runRWS :: RWS r w s a -> r -> s -> (a, s, w) #

Unwrap an RWS computation as a function. (The inverse of rws.)

evalRWS #

Arguments

:: RWS r w s a	RWS computation to execute
-> r	initial environment
-> s	initial value
-> (a, w)	final value and output

Evaluate a computation with the given initial state and environment, returning the final value and output, discarding the final state.

execRWS #

Arguments

:: RWS r w s a	RWS computation to execute
-> r	initial environment
-> s	initial value
-> (s, w)	final state and output

Evaluate a computation with the given initial state and environment, returning the final state and output, discarding the final value.

mapRWS :: ((a, s, w) -> (b, s, w')) -> RWS r w s a -> RWS r w' s b #

Map the return value, final state and output of a computation using the given function.

runRWS (mapRWS f m) r s = f (runRWS m r s)

withRWS :: (r' -> s -> (r, s)) -> RWS r w s a -> RWS r' w s a #

withRWS f m executes action m with an initial environment and state modified by applying f.

runRWS (withRWS f m) r s = uncurry (runRWS m) (f r s)

evalRWST #

Arguments

:: Monad m
=> RWST r w s m a	computation to execute
-> r	initial environment
-> s	initial value
-> m (a, w)	computation yielding final value and output

Evaluate a computation with the given initial state and environment, returning the final value and output, discarding the final state.

execRWST #

Arguments

:: Monad m
=> RWST r w s m a	computation to execute
-> r	initial environment
-> s	initial value
-> m (s, w)	computation yielding final state and output

Evaluate a computation with the given initial state and environment, returning the final state and output, discarding the final value.

mapRWST :: (m (a, s, w) -> n (b, s, w')) -> RWST r w s m a -> RWST r w' s n b #

Map the inner computation using the given function.

runRWST (mapRWST f m) r s = f (runRWST m r s)

withRWST :: forall r' s r w (m :: Type -> Type) a. (r' -> s -> (r, s)) -> RWST r w s m a -> RWST r' w s m a #

withRWST f m executes action m with an initial environment and state modified by applying f.

runRWST (withRWST f m) r s = uncurry (runRWST m) (f r s)

reader :: forall w (m :: Type -> Type) r a s. (Monoid w, Monad m) => (r -> a) -> RWST r w s m a #

Constructor for computations in the reader monad (equivalent to asks).

state :: forall w (m :: Type -> Type) s a r. (Monoid w, Monad m) => (s -> (a, s)) -> RWST r w s m a #

Construct a state monad computation from a state transformer function.

modify :: forall w (m :: Type -> Type) s r. (Monoid w, Monad m) => (s -> s) -> RWST r w s m () #

modify f is an action that updates the state to the result of applying f to the current state.

```
modify f = get >>= (put . f)
```

gets :: forall w (m :: Type -> Type) s a r. (Monoid w, Monad m) => (s -> a) -> RWST r w s m a #

Get a specific component of the state, using a projection function supplied.

```
gets f = liftM f get
```

writer :: forall (m :: Type -> Type) a w r s. Monad m => (a, w) -> RWST r w s m a #

Construct a writer computation from a (result, output) pair.

pass :: forall (m :: Type -> Type) r w s a. Monad m => RWST r w s m (a, w -> w) -> RWST r w s m a #

pass m is an action that executes the action m, which returns a value and a function, and returns the value, applying the function to the output.

runRWST (pass m) r s = liftM (\ ((a, f), w) -> (a, f w)) (runRWST m r s)