Control.Monad.Constrained.State

This module duplicates the Control.Monad.State module from mtl for monads with constraints.

Documentation

class Monad m => MonadState s m | m -> s where

A class for monads with state.

Minimal complete definition

state

Associated Types

type StateSuitable m a :: Constraint

Methods

get :: StateSuitable m s => m s

Return the state from the internals of the monad.

put :: (StateSuitable m (), StateSuitable m s) => s -> m ()

Replace the state inside the monad.

state :: (StateSuitable m a, StateSuitable m s) => (s -> (a, s)) -> m a

Embed a simple state action in the monad.

Instances

(MonadState s m, Monad (Unconstrained m)) => MonadState s (MaybeT m)

Associated Types

type StateSuitable (MaybeT m :: * -> *) a :: Constraint

Methods

get :: MaybeT m s

put :: s -> MaybeT m ()

state :: (StateSuitable (MaybeT m) a, StateSuitable (MaybeT m) s) => (s -> (a, s)) -> MaybeT m a

(MonadState s m, Monad (Unconstrained m)) => MonadState s (ExceptT e m)

Associated Types

type StateSuitable (ExceptT e m :: * -> *) a :: Constraint

Methods

get :: ExceptT e m s

put :: s -> ExceptT e m ()

state :: (StateSuitable (ExceptT e m) a, StateSuitable (ExceptT e m) s) => (s -> (a, s)) -> ExceptT e m a

MonadState s m => MonadState s (IdentityT * m)

Associated Types

type StateSuitable (IdentityT * m :: * -> *) a :: Constraint

Methods

get :: IdentityT * m s

put :: s -> IdentityT * m ()

state :: (StateSuitable (IdentityT * m) a, StateSuitable (IdentityT * m) s) => (s -> (a, s)) -> IdentityT * m a

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

Associated Types

type StateSuitable (StateT s m :: * -> *) a :: Constraint

Methods

get :: StateT s m s

put :: s -> StateT s m ()

state :: (StateSuitable (StateT s m) a, StateSuitable (StateT s m) s) => (s -> (a, s)) -> StateT s m a

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

Associated Types

type StateSuitable (StateT s m :: * -> *) a :: Constraint

Methods

get :: StateT s m s

put :: s -> StateT s m ()

state :: (StateSuitable (StateT s m) a, StateSuitable (StateT s m) s) => (s -> (a, s)) -> StateT s m a

(MonadState s m, Monad (Unconstrained m)) => MonadState s (WriterT w m)

Associated Types

type StateSuitable (WriterT w m :: * -> *) a :: Constraint

Methods

get :: WriterT w m s

put :: s -> WriterT w m ()

state :: (StateSuitable (WriterT w m) a, StateSuitable (WriterT w m) s) => (s -> (a, s)) -> WriterT w m a

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

Associated Types

type StateSuitable (ReaderT * r m :: * -> *) a :: Constraint

Methods

get :: ReaderT * r m s

put :: s -> ReaderT * r m ()

state :: (StateSuitable (ReaderT * r m) a, StateSuitable (ReaderT * r m) s) => (s -> (a, s)) -> ReaderT * r m a

(MonadState s m, Suitable m r) => MonadState s (ContT * r m)

Associated Types

type StateSuitable (ContT * r m :: * -> *) a :: Constraint

Methods

get :: ContT * r m s

put :: s -> ContT * r m ()

state :: (StateSuitable (ContT * r m) a, StateSuitable (ContT * r m) s) => (s -> (a, s)) -> ContT * r m a

newtype StateT s m 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

(MonadError e m, Monad (Unconstrained m)) => MonadError e (StateT s m)

Associated Types

type SuitableError (StateT s m :: * -> *) a :: Constraint

Methods

throwError :: SuitableError (StateT s m) a => e -> StateT s m a

catchError :: SuitableError (StateT s m) a => StateT s m a -> (e -> StateT s m a) -> StateT s m a

(MonadReader r m, Monad (Unconstrained m)) => MonadReader r (StateT s m)

Associated Types

type ReaderSuitable (StateT s m :: * -> *) a :: Constraint

Methods

ask :: StateT s m r

local :: (ReaderSuitable (StateT s m) a, ReaderSuitable (StateT s m) r) => (r -> r) -> StateT s m a -> StateT s m a

reader :: (ReaderSuitable (StateT s m) r, ReaderSuitable (StateT s m) a) => (r -> a) -> StateT s m a

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

Associated Types

type StateSuitable (StateT s m :: * -> *) a :: Constraint

Methods

get :: StateT s m s

put :: s -> StateT s m ()

state :: (StateSuitable (StateT s m) a, StateSuitable (StateT s m) s) => (s -> (a, s)) -> StateT s m a

(MonadWriter w m, Monad (Unconstrained m)) => MonadWriter w (StateT s m)

Associated Types

type WriterSuitable (StateT s m :: * -> *) a :: Constraint

Methods

writer :: WriterSuitable (StateT s m) a => (a, w) -> StateT s m a

tell :: w -> StateT s m ()

listenC :: WriterSuitable (StateT s m) b => (a -> w -> b) -> StateT s m a -> StateT s m b

passC :: WriterSuitable (StateT s m) a => (a -> w -> w) -> StateT s m a -> StateT s m a

MonadTrans (StateT s)

Methods

lift :: Monad m => m a -> StateT s m a

MonadTrans (StateT r)

Associated Types

type SuitableLift (StateT r :: (* -> *) -> * -> *) (m :: * -> *) a :: Constraint

Methods

lift :: (Monad m, SuitableLift (StateT r) m a) => m a -> StateT r m a

Monad m => Monad (StateT s m)

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

fail :: String -> StateT s m a

Functor m => Functor (StateT s m)

Methods

fmap :: (a -> b) -> StateT s m a -> StateT s m b

(<$) :: a -> StateT s m b -> StateT s m a

MonadFix m => MonadFix (StateT s m)

Methods

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

MonadFail m => MonadFail (StateT s m)

Methods

fail :: String -> StateT s m a

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

Methods

pure :: a -> StateT s m a

(<*>) :: StateT s m (a -> b) -> StateT s m a -> StateT s m b

(*>) :: StateT s m a -> StateT s m b -> StateT s m b

(<*) :: StateT s m a -> StateT s m b -> StateT s m a

MonadIO m => MonadIO (StateT s m)

Methods

liftIO :: IO a -> StateT s m a

(Functor m, MonadPlus m) => Alternative (StateT s m)

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]

MonadPlus m => MonadPlus (StateT s m)

Methods

mzero :: StateT s m a

mplus :: StateT s m a -> StateT s m a -> StateT s m a

(Monad m, Alternative m, Monad (Unconstrained m)) => Alternative (StateT s m)

Methods

empty :: Suitable (StateT s m) a => StateT s m a

(<|>) :: Suitable (StateT s m) a => StateT s m a -> StateT s m a -> StateT s m a

some :: Suitable (StateT s m) [a] => StateT s m a -> StateT s m [a]

many :: Suitable (StateT s m) [a] => StateT s m a -> StateT s m [a]

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

Methods

(>>=) :: Suitable (StateT s m) b => StateT s m a -> (a -> StateT s m b) -> StateT s m b

(Monad m, Monad (Unconstrained m)) => Applicative (StateT s m)

Associated Types

type Unconstrained (StateT s m :: * -> *) :: * -> *

Methods

reflect :: StateT s m a -> Unconstrained (StateT s m) a

reify :: Suitable (StateT s m) a => Unconstrained (StateT s m) a -> StateT s m a

pure :: Suitable (StateT s m) a => a -> StateT s m a

(<*>) :: Suitable (StateT s m) b => StateT s m (a -> b) -> StateT s m a -> StateT s m b

(*>) :: Suitable (StateT s m) b => StateT s m a -> StateT s m b -> StateT s m b

(<*) :: Suitable (StateT s m) a => StateT s m a -> StateT s m b -> StateT s m a

liftA2 :: Suitable (StateT s m) c => (a -> b -> c) -> StateT s m a -> StateT s m b -> StateT s m c

liftA3 :: Suitable (StateT s m) d => (a -> b -> c -> d) -> StateT s m a -> StateT s m b -> StateT s m c -> StateT s m d

Functor m => Functor (StateT s m)

Associated Types

type Suitable (StateT s m :: * -> *) a :: Constraint

Methods

fmap :: Suitable (StateT s m) b => (a -> b) -> StateT s m a -> StateT s m b

(<$) :: Suitable (StateT s m) a => a -> StateT s m b -> StateT s m a

Monad m => Monad (StateT s m)

Associated Types

type Suitable (StateT s m :: * -> *) a :: Constraint

Methods

(>>=) :: (Suitable (StateT s m) a, Suitable (StateT s m) b) => StateT s m a -> (a -> StateT s m b) -> StateT s m b

join :: Suitable (StateT s m) a => StateT s m (StateT s m a) -> StateT s m a

(MonadCont m, Monad (Unconstrained m)) => MonadCont (StateT s m)

Methods

callCC :: ((a -> StateT s m b) -> StateT s m a) -> StateT s m a

(MonadIO m, Monad (Unconstrained m)) => MonadIO (StateT s m)

Associated Types

type SuitableIO (StateT s m :: * -> *) a :: Constraint

Methods

liftIO :: SuitableIO (StateT s m) a => IO a -> StateT s m a

type SuitableLift (StateT r) m a

type SuitableLift (StateT r) m a = Suitable m (a, r)

type Unconstrained (StateT s m)

type Unconstrained (StateT s m) = StateT s (Unconstrained m)

type Suitable (StateT s m) a

type Suitable (StateT s m) a = Suitable m (a, s)

type Suitable (StateT s m) a

type Suitable (StateT s m) a = ()

type SuitableError (StateT s m) a

type SuitableError (StateT s m) a = (Suitable m (a, s), SuitableError m (a, s), SuitableError m a)

type SuitableIO (StateT s m) a

type SuitableIO (StateT s m) a = (SuitableIO m a, Suitable m (a, s))

type ReaderSuitable (StateT s m) a

type ReaderSuitable (StateT s m) a = (ReaderSuitable m a, ReaderSuitable m (a, s), Suitable m (a, s))

type StateSuitable (StateT s m) a

type StateSuitable (StateT s m) a = Suitable m (a, s)

type WriterSuitable (StateT s m) a

type WriterSuitable (StateT s m) a = (WriterSuitable m a, WriterSuitable m (a, s), Suitable m (a, s))

gets :: (StateSuitable m s, MonadState s m, Suitable m b) => (s -> b) -> m b

Get the state, while applying a transformation function.

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

Modify the state.

modify' :: (StateSuitable m (), StateSuitable m s, MonadState s m) => (s -> s) -> m ()

Modify the state, strictly in the new state.