Safe Haskell	Safe-Inferred
Language	Haskell2010

Control.Monad.Ology.Specific.StateT

Contents

Orphan instances

Synopsis

evalState :: State s a -> s -> a
evalStateT :: Monad m => StateT s m a -> s -> m a
execState :: State s a -> s -> s
execStateT :: Monad m => StateT s m a -> s -> m s
mapState :: ((a, s) -> (b, s)) -> State s a -> State s b
mapStateT :: (m (a, s) -> n (b, s)) -> StateT s m a -> StateT s n b
runState :: State s a -> s -> (a, s)
withState :: (s -> s) -> State s a -> State s a
withStateT :: forall s (m :: Type -> Type) a. (s -> s) -> StateT s m a -> StateT s m a
type State s = StateT s Identity
newtype StateT s (m :: Type -> Type) a = StateT {
- runStateT :: s -> m (a, s)
}
state :: forall (m :: Type -> Type) s a. Monad m => (s -> (a, s)) -> StateT s m a
put :: forall (m :: Type -> Type) s. Monad m => s -> StateT s m ()
modify' :: forall (m :: Type -> Type) s. Monad m => (s -> s) -> StateT s m ()
modify :: forall (m :: Type -> Type) s. Monad m => (s -> s) -> StateT s m ()
liftCallCC' :: CallCC m (a, s) (b, s) -> CallCC (StateT s m) a b
gets :: forall (m :: Type -> Type) s a. Monad m => (s -> a) -> StateT s m a
get :: forall (m :: Type -> Type) s. Monad m => StateT s m s
mVarRunStateT :: MVar s -> Unlift MonadTunnelIO (StateT s)
mVarRunLocked :: MonadTunnelIO m => MVar s -> m --> m
discardingStateTUnlift :: s -> Unlift MonadIO (StateT s)
dangerousMVarRunStateT :: MVar s -> Unlift MonadIO (StateT s)
liftStateT :: (Traversable f, Applicative m) => StateT s m a -> StateT (f s) m (f a)
liftWithMVarStateT :: MonadIO m => (MVar s -> m a) -> StateT s m a

Documentation

evalState #

Arguments

:: State s a	state-passing computation to execute
-> s	initial value
-> a	return value of the state computation

Evaluate a state computation with the given initial state and return the final value, discarding the final state.

```
evalState m s = fst (runState m s)
```

evalStateT :: Monad m => StateT s m a -> s -> m a #

Evaluate a state computation with the given initial state and return the final value, discarding the final state.

evalStateT m s = liftM fst (runStateT m s)

execState #

Arguments

:: State s a	state-passing computation to execute
-> s	initial value
-> s	final state

Evaluate a state computation with the given initial state and return the final state, discarding the final value.

```
execState m s = snd (runState m s)
```

execStateT :: Monad m => StateT s m a -> s -> m s #

Evaluate a state computation with the given initial state and return the final state, discarding the final value.

execStateT m s = liftM snd (runStateT m s)

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

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

runState (mapState f m) = f . runState m

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

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

runStateT (mapStateT f m) = f . runStateT m

runState #

Arguments

:: State s a	state-passing computation to execute
-> s	initial state
-> (a, s)	return value and final state

Unwrap a state monad computation as a function. (The inverse of state.)

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

withState f m executes action m on a state modified by applying f.

```
withState f m = modify f >> m
```

withStateT :: forall s (m :: Type -> Type) a. (s -> s) -> StateT s m a -> StateT s m a #

withStateT f m executes action m on a state modified by applying f.

```
withStateT f m = modify f >> m
```

type State s = StateT s Identity #

A state monad parameterized by the type s of the state to carry.

The return function leaves the state unchanged, while >>= uses the final state of the first computation as the initial state of the second.

newtype StateT s (m :: Type -> Type) a #

A state transformer monad parameterized by:

s - The state.
m - The inner monad.

The return function leaves the state unchanged, while >>= uses the final state of the first computation as the initial state of the second.

Constructors

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

Instances

Instances details

TransConstraint MonadFail (StateT s) Source #
Instance details Defined in Control.Monad.Ology.Specific.StateT Methods hasTransConstraint :: forall (m :: Type -> Type). MonadFail m => Dict (MonadFail (StateT s m)) Source #
TransConstraint MonadFix (StateT s) Source #
Instance details Defined in Control.Monad.Ology.Specific.StateT Methods hasTransConstraint :: forall (m :: Type -> Type). MonadFix m => Dict (MonadFix (StateT s m)) Source #
TransConstraint MonadIO (StateT s) Source #
Instance details Defined in Control.Monad.Ology.Specific.StateT Methods hasTransConstraint :: forall (m :: Type -> Type). MonadIO m => Dict (MonadIO (StateT s m)) Source #
TransConstraint Functor (StateT s) Source #
Instance details Defined in Control.Monad.Ology.Specific.StateT Methods hasTransConstraint :: forall (m :: Type -> Type). Functor m => Dict (Functor (StateT s m)) Source #
TransConstraint Monad (StateT s) Source #
Instance details Defined in Control.Monad.Ology.Specific.StateT Methods hasTransConstraint :: forall (m :: Type -> Type). Monad m => Dict (Monad (StateT s m)) Source #
TransConstraint MonadPlus (StateT s) Source #
Instance details Defined in Control.Monad.Ology.Specific.StateT Methods hasTransConstraint :: forall (m :: Type -> Type). MonadPlus m => Dict (MonadPlus (StateT s m)) Source #
TransConstraint MonadException (StateT s) Source #
Instance details Defined in Control.Monad.Ology.Specific.StateT Methods hasTransConstraint :: forall (m :: Type -> Type). MonadException m => Dict (MonadException (StateT s m)) Source #
MonadCatch e m => MonadCatch e (StateT s m) Source #
Instance details Defined in Control.Monad.Ology.Specific.StateT Methods catch :: StateT s m a -> (e -> StateT s m a) -> StateT s m a Source #
MonadThrow e m => MonadThrow e (StateT s m) Source #
Instance details Defined in Control.Monad.Ology.Specific.StateT Methods throw :: e -> StateT s m a Source #
MonadTransCoerce (StateT a) Source #
Instance details Defined in Control.Monad.Ology.Specific.StateT Methods transCoerce :: forall (m1 :: Type -> Type) (m2 :: Type -> Type). Coercible m1 m2 => Dict (Coercible (StateT a m1) (StateT a m2)) Source #
MonadTransHoist (StateT s) Source #
Instance details Defined in Control.Monad.Ology.Specific.StateT Methods hoist :: forall (m1 :: Type -> Type) (m2 :: Type -> Type). (Monad m1, Monad m2) => (m1 --> m2) -> StateT s m1 --> StateT s m2 Source #
MonadTransTunnel (StateT s) Source #
Instance details Defined in Control.Monad.Ology.Specific.StateT Associated Types type Tunnel (StateT s) :: Type -> Type Source # Methods tunnel :: Monad m => ((forall (m1 :: Type -> Type) a. Monad m1 => StateT s m1 a -> m1 (Tunnel (StateT s) a)) -> m (Tunnel (StateT s) r)) -> StateT s m r Source #
MonadTransUnlift (StateT s) Source #
Instance details Defined in Control.Monad.Ology.Specific.StateT Methods liftWithUnlift :: MonadIO m => (Unlift MonadTunnelIO (StateT s) -> m r) -> StateT s m r Source # getDiscardingUnlift :: forall (m :: Type -> Type). Monad m => StateT s m (WUnlift MonadTunnelIO (StateT s)) Source #
MonadTrans (StateT s)
Instance details Defined in Control.Monad.Trans.State.Lazy Methods lift :: Monad m => m a -> StateT s m a #
TransConstraint (MonadCatch e) (StateT s) Source #
Instance details Defined in Control.Monad.Ology.Specific.StateT Methods hasTransConstraint :: forall (m :: Type -> Type). MonadCatch e m => Dict (MonadCatch e (StateT s m)) Source #
TransConstraint (MonadThrow e) (StateT s) Source #
Instance details Defined in Control.Monad.Ology.Specific.StateT Methods hasTransConstraint :: forall (m :: Type -> Type). MonadThrow e m => Dict (MonadThrow e (StateT s m)) Source #
MonadFail m => MonadFail (StateT s m)
Instance details Defined in Control.Monad.Trans.State.Lazy Methods fail :: String -> StateT s m a #
MonadFix m => MonadFix (StateT s m)
Instance details Defined in Control.Monad.Trans.State.Lazy Methods mfix :: (a -> StateT s m a) -> StateT s m a #
MonadIO m => MonadIO (StateT s m)
Instance details Defined in Control.Monad.Trans.State.Lazy Methods liftIO :: IO a -> StateT s m a #
Contravariant m => Contravariant (StateT s m)
Instance details Defined in Control.Monad.Trans.State.Lazy Methods contramap :: (a' -> a) -> StateT s m a -> StateT s m a' # (>$) :: b -> StateT s m b -> StateT s m a #
(Functor m, MonadPlus m) => Alternative (StateT s m)
Instance details Defined in Control.Monad.Trans.State.Lazy Methods empty :: StateT s m a # (<\|>) :: StateT s m a -> StateT s m a -> StateT s m a # some :: StateT s m a -> StateT s m [a] # many :: StateT s m a -> StateT s m [a] #
(Functor m, Monad m) => Applicative (StateT s m)
Instance details Defined in Control.Monad.Trans.State.Lazy Methods pure :: a -> StateT s m a # (<>) :: StateT s m (a -> b) -> StateT s m a -> StateT s m b # liftA2 :: (a -> b -> c) -> StateT s m a -> StateT s m b -> StateT s m c # (>) :: StateT s m a -> StateT s m b -> StateT s m b # (<*) :: StateT s m a -> StateT s m b -> StateT s m a #
Functor m => Functor (StateT s m)
Instance details Defined in Control.Monad.Trans.State.Lazy Methods fmap :: (a -> b) -> StateT s m a -> StateT s m b # (<$) :: a -> StateT s m b -> StateT s m a #
Monad m => Monad (StateT s m)
Instance details Defined in Control.Monad.Trans.State.Lazy Methods (>>=) :: StateT s m a -> (a -> StateT s m b) -> StateT s m b # (>>) :: StateT s m a -> StateT s m b -> StateT s m b # return :: a -> StateT s m a #
MonadPlus m => MonadPlus (StateT s m)
Instance details Defined in Control.Monad.Trans.State.Lazy Methods mzero :: StateT s m a # mplus :: StateT s m a -> StateT s m a -> StateT s m a #
Invariant m => Invariant (StateT s m)	from the `transformers` package
Instance details Defined in Data.Functor.Invariant Methods invmap :: (a -> b) -> (b -> a) -> StateT s m a -> StateT s m b #
MonadException m => MonadException (StateT s m) Source #
Instance details Defined in Control.Monad.Ology.Specific.StateT Associated Types type Exc (StateT s m) Source # Methods throwExc :: Exc (StateT s m) -> StateT s m a Source # catchExc :: StateT s m a -> (Exc (StateT s m) -> StateT s m a) -> StateT s m a Source #
type Tunnel (StateT s) Source #
Instance details Defined in Control.Monad.Ology.Specific.StateT type Tunnel (StateT s) = (,) (Endo s)
type Exc (StateT s m) Source #
Instance details Defined in Control.Monad.Ology.Specific.StateT type Exc (StateT s m) = Exc m

state #

Arguments

:: forall (m :: Type -> Type) s a. Monad m
=> (s -> (a, s))	pure state transformer
-> StateT s m a	equivalent state-passing computation

Construct a state monad computation from a function. (The inverse of runState.)

put :: forall (m :: Type -> Type) s. Monad m => s -> StateT s m () #

put s sets the state within the monad to s.

modify' :: forall (m :: Type -> Type) s. Monad m => (s -> s) -> StateT s m () #

A variant of modify in which the computation is strict in the new state.

```
modify' f = get >>= (($!) put . f)
```

modify :: forall (m :: Type -> Type) s. Monad m => (s -> s) -> StateT 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)
```

liftCallCC' :: CallCC m (a, s) (b, s) -> CallCC (StateT 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. It does not satisfy the uniformity property (see Control.Monad.Signatures).

gets :: forall (m :: Type -> Type) s a. Monad m => (s -> a) -> StateT s m a #

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

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

get :: forall (m :: Type -> Type) s. Monad m => StateT s m s #

Fetch the current value of the state within the monad.

mVarRunStateT :: MVar s -> Unlift MonadTunnelIO (StateT s) Source #

Run the StateT on an MVar, taking the initial state and putting the final state.

mVarRunLocked :: MonadTunnelIO m => MVar s -> m --> m Source #

Take the MVar before and put it back after.

discardingStateTUnlift :: s -> Unlift MonadIO (StateT s) Source #

dangerousMVarRunStateT :: MVar s -> Unlift MonadIO (StateT s) Source #

Dangerous, because the MVar won't be released on exception.

liftStateT :: (Traversable f, Applicative m) => StateT s m a -> StateT (f s) m (f a) Source #

liftWithMVarStateT :: MonadIO m => (MVar s -> m a) -> StateT s m a Source #

Orphan instances

TransConstraint MonadFail (StateT s) Source #
Instance details Methods hasTransConstraint :: forall (m :: Type -> Type). MonadFail m => Dict (MonadFail (StateT s m)) Source #
TransConstraint MonadFix (StateT s) Source #
Instance details Methods hasTransConstraint :: forall (m :: Type -> Type). MonadFix m => Dict (MonadFix (StateT s m)) Source #
TransConstraint MonadIO (StateT s) Source #
Instance details Methods hasTransConstraint :: forall (m :: Type -> Type). MonadIO m => Dict (MonadIO (StateT s m)) Source #
TransConstraint Functor (StateT s) Source #
Instance details Methods hasTransConstraint :: forall (m :: Type -> Type). Functor m => Dict (Functor (StateT s m)) Source #
TransConstraint Monad (StateT s) Source #
Instance details Methods hasTransConstraint :: forall (m :: Type -> Type). Monad m => Dict (Monad (StateT s m)) Source #
TransConstraint MonadPlus (StateT s) Source #
Instance details Methods hasTransConstraint :: forall (m :: Type -> Type). MonadPlus m => Dict (MonadPlus (StateT s m)) Source #
TransConstraint MonadException (StateT s) Source #
Instance details Methods hasTransConstraint :: forall (m :: Type -> Type). MonadException m => Dict (MonadException (StateT s m)) Source #
MonadCatch e m => MonadCatch e (StateT s m) Source #
Instance details Methods catch :: StateT s m a -> (e -> StateT s m a) -> StateT s m a Source #
MonadThrow e m => MonadThrow e (StateT s m) Source #
Instance details Methods throw :: e -> StateT s m a Source #
MonadTransCoerce (StateT a) Source #
Instance details Methods transCoerce :: forall (m1 :: Type -> Type) (m2 :: Type -> Type). Coercible m1 m2 => Dict (Coercible (StateT a m1) (StateT a m2)) Source #
MonadTransHoist (StateT s) Source #
Instance details Methods hoist :: forall (m1 :: Type -> Type) (m2 :: Type -> Type). (Monad m1, Monad m2) => (m1 --> m2) -> StateT s m1 --> StateT s m2 Source #
MonadTransTunnel (StateT s) Source #
Instance details Associated Types type Tunnel (StateT s) :: Type -> Type Source # Methods tunnel :: Monad m => ((forall (m1 :: Type -> Type) a. Monad m1 => StateT s m1 a -> m1 (Tunnel (StateT s) a)) -> m (Tunnel (StateT s) r)) -> StateT s m r Source #
MonadTransUnlift (StateT s) Source #
Instance details Methods liftWithUnlift :: MonadIO m => (Unlift MonadTunnelIO (StateT s) -> m r) -> StateT s m r Source # getDiscardingUnlift :: forall (m :: Type -> Type). Monad m => StateT s m (WUnlift MonadTunnelIO (StateT s)) Source #
TransConstraint (MonadCatch e) (StateT s) Source #
Instance details Methods hasTransConstraint :: forall (m :: Type -> Type). MonadCatch e m => Dict (MonadCatch e (StateT s m)) Source #
TransConstraint (MonadThrow e) (StateT s) Source #
Instance details Methods hasTransConstraint :: forall (m :: Type -> Type). MonadThrow e m => Dict (MonadThrow e (StateT s m)) Source #
MonadException m => MonadException (StateT s m) Source #
Instance details Associated Types type Exc (StateT s m) Source # Methods throwExc :: Exc (StateT s m) -> StateT s m a Source # catchExc :: StateT s m a -> (Exc (StateT s m) -> StateT s m a) -> StateT s m a Source #