Moduleadjunctions-4.4.3Haskell2010

Control.Monad.Representable.State

A generalized State monad, parameterized by a Representable functor. The representation of that functor serves as the state.

2 types
1 class
11 values

Packageadjunctions-4.4.3
Exports14
LanguageHaskell2010
LicenceBSD-2-Clause
SourceState.hs

typetype State (g :: Type -> Type) = StateT g Identity

A memoized state monad parameterized by a representable functor g, where the representatation of g, Rep g is 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.

valuerunState

:: Representable g
=> State g a
state-passing computation to execute
-> Rep g
initial state
-> (a, Rep g)
return value and final state

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

valueevalState

:: Representable g
=> State g a
state-passing computation to execute
-> Rep g
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)
```

valueexecState

:: Representable g
=> State g a
state-passing computation to execute
-> Rep g
initial value
-> Rep g
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)
```

valuemapState

:: Functor g
=> (a, Rep g) -> (b, Rep g)
-> State g a
-> State g b

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

runState (mapState f m) = f . runState m

newtypenewtype StateT (g :: Type -> Type) (m :: Type -> Type) a

A state transformer monad parameterized by:

g - A representable functor used to memoize results for a state Rep g
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
- getStateT :: g (m (a, Rep g))

Instances12MonadReader, MonadState, MonadWriter, MonadFree, MonadTrans, BindTrans, …

(Representable g, MonadReader e m) => MonadReader e (StateT g m)Defined in adjunctions-4.4.3 · Control.Monad.Representable.State
(Representable g, Monad m, Rep g ~ s) => MonadState s (StateT g m)Defined in adjunctions-4.4.3 · Control.Monad.Representable.State
(Representable g, MonadWriter w m) => MonadWriter w (StateT g m)Defined in adjunctions-4.4.3 · Control.Monad.Representable.State
(Functor f, Representable g, MonadFree f m) => MonadFree f (StateT g m)Defined in adjunctions-4.4.3 · Control.Monad.Representable.State
Representable f => MonadTrans (StateT f)Defined in adjunctions-4.4.3 · Control.Monad.Representable.State
Representable f => BindTrans (StateT f)Defined in adjunctions-4.4.3 · Control.Monad.Representable.State
(Representable g, Monad m) => Monad (StateT g m)Defined in adjunctions-4.4.3 · Control.Monad.Representable.State
(Functor g, Functor m) => Functor (StateT g m)Defined in adjunctions-4.4.3 · Control.Monad.Representable.State
(Representable g, Functor m, Monad m) => Applicative (StateT g m)Defined in adjunctions-4.4.3 · Control.Monad.Representable.State
(Representable g, MonadCont m) => MonadCont (StateT g m)Defined in adjunctions-4.4.3 · Control.Monad.Representable.State
(Representable g, Bind m) => Apply (StateT g m)Defined in adjunctions-4.4.3 · Control.Monad.Representable.State
(Representable g, Bind m) => Bind (StateT g m)Defined in adjunctions-4.4.3 · Control.Monad.Representable.State

valuestateT :: Representable g => (Rep g -> m (a, Rep g)) -> StateT g m a

valuerunStateT :: Representable g => StateT g m a -> Rep g -> m (a, Rep g)

valueevalStateT :: (Representable g, Monad m) => StateT g m a -> Rep g -> 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)

valueexecStateT

:: (Representable g, Monad m)
=> StateT g m a
-> Rep g
-> m (Rep g)

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)

valuemapStateT

:: Functor g
=> m (a, Rep g) -> n (b, Rep g)
-> StateT g m a
-> StateT g n b

valueliftCallCC

:: Representable g
=> (((a, Rep g) -> m (b, Rep g)) -> m (a, Rep g)) -> m (a, Rep g)
-> (a -> StateT g m b) -> StateT g m a
-> StateT g m a

Uniform lifting of a callCC operation to the new monad. This version rolls back to the original state on entering the continuation.

valueliftCallCC'

:: Representable g
=> (((a, Rep g) -> m (b, Rep g)) -> m (a, Rep g)) -> m (a, Rep g)
-> (a -> StateT g m b) -> StateT g m a
-> StateT g m a

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 laws of a monad transformer.

classclass Monad m => MonadState s (m :: Type -> Type) | m -> s where

Minimal definition is either both of get and put or just state

Methods

get :: m s
Return the state from the internals of the monad.
put :: s -> m ()
Replace the state inside the monad.
state :: (s -> (a, s)) -> m a
Embed a simple state action into the monad.

Instances24MonadState, …

MonadState s m => MonadState s (CatchT m)Defined in exceptions-0.10.9 · Control.Monad.Catch.Pure
MonadState s m => MonadState s (Free m)Defined in free-5.2 · Control.Monad.Free
MonadState s m => MonadState s (Free m)Defined in free-5.2 · Control.Monad.Free.Ap
MonadState s m => MonadState s (F m)Defined in free-5.2 · Control.Monad.Free.Church
MonadState s m => MonadState s (IterT m)Defined in free-5.2 · Control.Monad.Trans.Iter
MonadState s m => MonadState s (MaybeT m)Defined in mtl-2.3.1 · Control.Monad.State.Class
Monad m => MonadState s (StateT s m)Defined in mtl-2.3.1 · Control.Monad.State.Class
Monad m => MonadState s (StateT s m)Defined in mtl-2.3.1 · Control.Monad.State.Class
MonadState s m => MonadState s (FT f m)Defined in free-5.2 · Control.Monad.Trans.Free.Church
MonadState s m => MonadState s (ExceptT e m)Defined in mtl-2.3.1 · Control.Monad.State.Class
MonadState s m => MonadState s (IdentityT m)Defined in mtl-2.3.1 · Control.Monad.State.Class
MonadState s m => MonadState s (ReaderT r m)Defined in mtl-2.3.1 · Control.Monad.State.Class
MonadState s m => MonadState s (SelectT r m)Defined in mtl-2.3.1 · Control.Monad.State.Class
(Representable g, Monad m, Rep g ~ s) => MonadState s (StateT g m)Defined in adjunctions-4.4.3 · Control.Monad.Representable.State
(Applicative f, MonadState s m) => MonadState s (FreeT f m)Defined in free-5.2 · Control.Monad.Trans.Free.Ap
(Functor f, MonadState s m) => MonadState s (FreeT f m)Defined in free-5.2 · Control.Monad.Trans.Free
(Monoid w, MonadState s m) => MonadState s (AccumT w m)Defined in mtl-2.3.1 · Control.Monad.State.Class
(Monoid w, MonadState s m) => MonadState s (WriterT w m)Defined in mtl-2.3.1 · Control.Monad.State.Class
(Monoid w, MonadState s m) => MonadState s (WriterT w m)Defined in mtl-2.3.1 · Control.Monad.State.Class
(Monoid w, MonadState s m) => MonadState s (WriterT w m)Defined in mtl-2.3.1 · Control.Monad.State.Class
MonadState s m => MonadState s (ContT r m)Defined in mtl-2.3.1 · Control.Monad.State.Class
(Monad m, Monoid w) => MonadState s (RWST r w s m)Defined in mtl-2.3.1 · Control.Monad.State.Class
(Monad m, Monoid w) => MonadState s (RWST r w s m)Defined in mtl-2.3.1 · Control.Monad.State.Class
(Monad m, Monoid w) => MonadState s (RWST r w s m)Defined in mtl-2.3.1 · Control.Monad.State.Class