Control.Monad.ST.Trans

This library provides a monad transformer version of the ST monad.

Warning! This monad transformer should not be used with monads that can contain multiple answers, like the list monad. The reason is that the state token will be duplicated across the different answers and this causes Bad Things to happen (such as loss of referential transparency). Safe monads include the monads State, Reader, Writer, Maybe and combinations of their corresponding monad transformers.

The ST Monad Transformer

data STT s m a

STT is the monad transformer providing polymorphic updateable references

Instances

MonadError e m => MonadError e (STT s m)

Methods

throwError :: e -> STT s m a

catchError :: STT s m a -> (e -> STT s m a) -> STT s m a

MonadReader r m => MonadReader r (STT s m)

Methods

ask :: STT s m r

local :: (r -> r) -> STT s m a -> STT s m a

reader :: (r -> a) -> STT s m a

MonadState s m => MonadState s (STT s' m)

Methods

get :: STT s' m s

put :: s -> STT s' m ()

state :: (s -> (a, s)) -> STT s' m a

MonadWriter w m => MonadWriter w (STT s m)

Methods

writer :: (a, w) -> STT s m a

tell :: w -> STT s m ()

listen :: STT s m a -> STT s m (a, w)

pass :: STT s m (a, w -> w) -> STT s m a

MonadTrans (STT s)

Methods

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

(Applicative m, Monad m) => MArray (STUArray s) Word64 (STT s m)

Methods

getBounds :: Ix i => STUArray s i Word64 -> STT s m (i, i)

getNumElements :: Ix i => STUArray s i Word64 -> STT s m Int

newArray :: Ix i => (i, i) -> Word64 -> STT s m (STUArray s i Word64)

newArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Word64)

unsafeNewArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Word64)

unsafeRead :: Ix i => STUArray s i Word64 -> Int -> STT s m Word64

unsafeWrite :: Ix i => STUArray s i Word64 -> Int -> Word64 -> STT s m ()

(Applicative m, Monad m) => MArray (STUArray s) Word32 (STT s m)

Methods

getBounds :: Ix i => STUArray s i Word32 -> STT s m (i, i)

getNumElements :: Ix i => STUArray s i Word32 -> STT s m Int

newArray :: Ix i => (i, i) -> Word32 -> STT s m (STUArray s i Word32)

newArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Word32)

unsafeNewArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Word32)

unsafeRead :: Ix i => STUArray s i Word32 -> Int -> STT s m Word32

unsafeWrite :: Ix i => STUArray s i Word32 -> Int -> Word32 -> STT s m ()

(Applicative m, Monad m) => MArray (STUArray s) Word16 (STT s m)

Methods

getBounds :: Ix i => STUArray s i Word16 -> STT s m (i, i)

getNumElements :: Ix i => STUArray s i Word16 -> STT s m Int

newArray :: Ix i => (i, i) -> Word16 -> STT s m (STUArray s i Word16)

newArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Word16)

unsafeNewArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Word16)

unsafeRead :: Ix i => STUArray s i Word16 -> Int -> STT s m Word16

unsafeWrite :: Ix i => STUArray s i Word16 -> Int -> Word16 -> STT s m ()

(Applicative m, Monad m) => MArray (STUArray s) Word8 (STT s m)

Methods

getBounds :: Ix i => STUArray s i Word8 -> STT s m (i, i)

getNumElements :: Ix i => STUArray s i Word8 -> STT s m Int

newArray :: Ix i => (i, i) -> Word8 -> STT s m (STUArray s i Word8)

newArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Word8)

unsafeNewArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Word8)

unsafeRead :: Ix i => STUArray s i Word8 -> Int -> STT s m Word8

unsafeWrite :: Ix i => STUArray s i Word8 -> Int -> Word8 -> STT s m ()

(Applicative m, Monad m) => MArray (STUArray s) Int64 (STT s m)

Methods

getBounds :: Ix i => STUArray s i Int64 -> STT s m (i, i)

getNumElements :: Ix i => STUArray s i Int64 -> STT s m Int

newArray :: Ix i => (i, i) -> Int64 -> STT s m (STUArray s i Int64)

newArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Int64)

unsafeNewArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Int64)

unsafeRead :: Ix i => STUArray s i Int64 -> Int -> STT s m Int64

unsafeWrite :: Ix i => STUArray s i Int64 -> Int -> Int64 -> STT s m ()

(Applicative m, Monad m) => MArray (STUArray s) Int32 (STT s m)

Methods

getBounds :: Ix i => STUArray s i Int32 -> STT s m (i, i)

getNumElements :: Ix i => STUArray s i Int32 -> STT s m Int

newArray :: Ix i => (i, i) -> Int32 -> STT s m (STUArray s i Int32)

newArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Int32)

unsafeNewArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Int32)

unsafeRead :: Ix i => STUArray s i Int32 -> Int -> STT s m Int32

unsafeWrite :: Ix i => STUArray s i Int32 -> Int -> Int32 -> STT s m ()

(Applicative m, Monad m) => MArray (STUArray s) Int16 (STT s m)

Methods

getBounds :: Ix i => STUArray s i Int16 -> STT s m (i, i)

getNumElements :: Ix i => STUArray s i Int16 -> STT s m Int

newArray :: Ix i => (i, i) -> Int16 -> STT s m (STUArray s i Int16)

newArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Int16)

unsafeNewArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Int16)

unsafeRead :: Ix i => STUArray s i Int16 -> Int -> STT s m Int16

unsafeWrite :: Ix i => STUArray s i Int16 -> Int -> Int16 -> STT s m ()

(Applicative m, Monad m) => MArray (STUArray s) Int8 (STT s m)

Methods

getBounds :: Ix i => STUArray s i Int8 -> STT s m (i, i)

getNumElements :: Ix i => STUArray s i Int8 -> STT s m Int

newArray :: Ix i => (i, i) -> Int8 -> STT s m (STUArray s i Int8)

newArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Int8)

unsafeNewArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Int8)

unsafeRead :: Ix i => STUArray s i Int8 -> Int -> STT s m Int8

unsafeWrite :: Ix i => STUArray s i Int8 -> Int -> Int8 -> STT s m ()

(Applicative m, Monad m) => MArray (STUArray s) Double (STT s m)

Methods

getBounds :: Ix i => STUArray s i Double -> STT s m (i, i)

getNumElements :: Ix i => STUArray s i Double -> STT s m Int

newArray :: Ix i => (i, i) -> Double -> STT s m (STUArray s i Double)

newArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Double)

unsafeNewArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Double)

unsafeRead :: Ix i => STUArray s i Double -> Int -> STT s m Double

unsafeWrite :: Ix i => STUArray s i Double -> Int -> Double -> STT s m ()

(Applicative m, Monad m) => MArray (STUArray s) Float (STT s m)

Methods

getBounds :: Ix i => STUArray s i Float -> STT s m (i, i)

getNumElements :: Ix i => STUArray s i Float -> STT s m Int

newArray :: Ix i => (i, i) -> Float -> STT s m (STUArray s i Float)

newArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Float)

unsafeNewArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Float)

unsafeRead :: Ix i => STUArray s i Float -> Int -> STT s m Float

unsafeWrite :: Ix i => STUArray s i Float -> Int -> Float -> STT s m ()

(Applicative m, Monad m) => MArray (STUArray s) Word (STT s m)

Methods

getBounds :: Ix i => STUArray s i Word -> STT s m (i, i)

getNumElements :: Ix i => STUArray s i Word -> STT s m Int

newArray :: Ix i => (i, i) -> Word -> STT s m (STUArray s i Word)

newArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Word)

unsafeNewArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Word)

unsafeRead :: Ix i => STUArray s i Word -> Int -> STT s m Word

unsafeWrite :: Ix i => STUArray s i Word -> Int -> Word -> STT s m ()

(Applicative m, Monad m) => MArray (STUArray s) Int (STT s m)

Methods

getBounds :: Ix i => STUArray s i Int -> STT s m (i, i)

getNumElements :: Ix i => STUArray s i Int -> STT s m Int

newArray :: Ix i => (i, i) -> Int -> STT s m (STUArray s i Int)

newArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Int)

unsafeNewArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Int)

unsafeRead :: Ix i => STUArray s i Int -> Int -> STT s m Int

unsafeWrite :: Ix i => STUArray s i Int -> Int -> Int -> STT s m ()

(Applicative m, Monad m) => MArray (STUArray s) Char (STT s m)

Methods

getBounds :: Ix i => STUArray s i Char -> STT s m (i, i)

getNumElements :: Ix i => STUArray s i Char -> STT s m Int

newArray :: Ix i => (i, i) -> Char -> STT s m (STUArray s i Char)

newArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Char)

unsafeNewArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Char)

unsafeRead :: Ix i => STUArray s i Char -> Int -> STT s m Char

unsafeWrite :: Ix i => STUArray s i Char -> Int -> Char -> STT s m ()

(Applicative m, Monad m) => MArray (STUArray s) Bool (STT s m)

Methods

getBounds :: Ix i => STUArray s i Bool -> STT s m (i, i)

getNumElements :: Ix i => STUArray s i Bool -> STT s m Int

newArray :: Ix i => (i, i) -> Bool -> STT s m (STUArray s i Bool)

newArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Bool)

unsafeNewArray_ :: Ix i => (i, i) -> STT s m (STUArray s i Bool)

unsafeRead :: Ix i => STUArray s i Bool -> Int -> STT s m Bool

unsafeWrite :: Ix i => STUArray s i Bool -> Int -> Bool -> STT s m ()

(Applicative m, Monad m) => MArray (STArray s) e (STT s m)

Methods

getBounds :: Ix i => STArray s i e -> STT s m (i, i)

getNumElements :: Ix i => STArray s i e -> STT s m Int

newArray :: Ix i => (i, i) -> e -> STT s m (STArray s i e)

newArray_ :: Ix i => (i, i) -> STT s m (STArray s i e)

unsafeNewArray_ :: Ix i => (i, i) -> STT s m (STArray s i e)

unsafeRead :: Ix i => STArray s i e -> Int -> STT s m e

unsafeWrite :: Ix i => STArray s i e -> Int -> e -> STT s m ()

(Applicative m, Monad m) => MArray (STUArray s) (StablePtr a) (STT s m)

Methods

getBounds :: Ix i => STUArray s i (StablePtr a) -> STT s m (i, i)

getNumElements :: Ix i => STUArray s i (StablePtr a) -> STT s m Int

newArray :: Ix i => (i, i) -> StablePtr a -> STT s m (STUArray s i (StablePtr a))

newArray_ :: Ix i => (i, i) -> STT s m (STUArray s i (StablePtr a))

unsafeNewArray_ :: Ix i => (i, i) -> STT s m (STUArray s i (StablePtr a))

unsafeRead :: Ix i => STUArray s i (StablePtr a) -> Int -> STT s m (StablePtr a)

unsafeWrite :: Ix i => STUArray s i (StablePtr a) -> Int -> StablePtr a -> STT s m ()

(Applicative m, Monad m) => MArray (STUArray s) (FunPtr a) (STT s m)

Methods

getBounds :: Ix i => STUArray s i (FunPtr a) -> STT s m (i, i)

getNumElements :: Ix i => STUArray s i (FunPtr a) -> STT s m Int

newArray :: Ix i => (i, i) -> FunPtr a -> STT s m (STUArray s i (FunPtr a))

newArray_ :: Ix i => (i, i) -> STT s m (STUArray s i (FunPtr a))

unsafeNewArray_ :: Ix i => (i, i) -> STT s m (STUArray s i (FunPtr a))

unsafeRead :: Ix i => STUArray s i (FunPtr a) -> Int -> STT s m (FunPtr a)

unsafeWrite :: Ix i => STUArray s i (FunPtr a) -> Int -> FunPtr a -> STT s m ()

(Applicative m, Monad m) => MArray (STUArray s) (Ptr a) (STT s m)

Methods

getBounds :: Ix i => STUArray s i (Ptr a) -> STT s m (i, i)

getNumElements :: Ix i => STUArray s i (Ptr a) -> STT s m Int

newArray :: Ix i => (i, i) -> Ptr a -> STT s m (STUArray s i (Ptr a))

newArray_ :: Ix i => (i, i) -> STT s m (STUArray s i (Ptr a))

unsafeNewArray_ :: Ix i => (i, i) -> STT s m (STUArray s i (Ptr a))

unsafeRead :: Ix i => STUArray s i (Ptr a) -> Int -> STT s m (Ptr a)

unsafeWrite :: Ix i => STUArray s i (Ptr a) -> Int -> Ptr a -> STT s m ()

Monad m => Monad (STT s m)

Methods

(>>=) :: STT s m a -> (a -> STT s m b) -> STT s m b

(>>) :: STT s m a -> STT s m b -> STT s m b

return :: a -> STT s m a

fail :: String -> STT s m a

Functor m => Functor (STT s m)

Methods

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

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

MonadFix m => MonadFix (STT s m)

Methods

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

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

Methods

pure :: a -> STT s m a

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

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

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

runST :: Monad m => (forall s. STT s m a) -> m a

Deprecated: Use runSTT instead

Executes a computation in the STT monad transformer

runSTT :: Monad m => (forall s. STT s m a) -> m a

Executes a computation in the STT monad transformer

Mutable references

data STRef s a :: * -> * -> *

a value of type STRef s a is a mutable variable in state thread s, containing a value of type a

Instances

Eq (STRef s a)

Methods

(==) :: STRef s a -> STRef s a -> Bool

(/=) :: STRef s a -> STRef s a -> Bool

newSTRef :: (Applicative m, Monad m) => a -> STT s m (STRef s a)

Create a new reference

readSTRef :: (Applicative m, Monad m) => STRef s a -> STT s m a

Reads the value of a reference

writeSTRef :: (Applicative m, Monad m) => STRef s a -> a -> STT s m ()

Modifies the value of a reference

Mutable arrays

data STArray s i e :: * -> * -> * -> *

Mutable, boxed, non-strict arrays in the ST monad. The type arguments are as follows:

• s: the state variable argument for the ST type
• i: the index type of the array (should be an instance of Ix)
• e: the element type of the array.

Instances

MArray (STArray s) e (ST s)

Methods

getBounds :: Ix i => STArray s i e -> ST s (i, i)

getNumElements :: Ix i => STArray s i e -> ST s Int

newArray :: Ix i => (i, i) -> e -> ST s (STArray s i e)

newArray_ :: Ix i => (i, i) -> ST s (STArray s i e)

unsafeNewArray_ :: Ix i => (i, i) -> ST s (STArray s i e)

unsafeRead :: Ix i => STArray s i e -> Int -> ST s e

unsafeWrite :: Ix i => STArray s i e -> Int -> e -> ST s ()

MArray (STArray s) e (ST s)

Methods

getBounds :: Ix i => STArray s i e -> ST s (i, i)

getNumElements :: Ix i => STArray s i e -> ST s Int

newArray :: Ix i => (i, i) -> e -> ST s (STArray s i e)

newArray_ :: Ix i => (i, i) -> ST s (STArray s i e)

unsafeNewArray_ :: Ix i => (i, i) -> ST s (STArray s i e)

unsafeRead :: Ix i => STArray s i e -> Int -> ST s e

unsafeWrite :: Ix i => STArray s i e -> Int -> e -> ST s ()

(Applicative m, Monad m) => MArray (STArray s) e (STT s m)

Methods

getBounds :: Ix i => STArray s i e -> STT s m (i, i)

getNumElements :: Ix i => STArray s i e -> STT s m Int

newArray :: Ix i => (i, i) -> e -> STT s m (STArray s i e)

newArray_ :: Ix i => (i, i) -> STT s m (STArray s i e)

unsafeNewArray_ :: Ix i => (i, i) -> STT s m (STArray s i e)

unsafeRead :: Ix i => STArray s i e -> Int -> STT s m e

unsafeWrite :: Ix i => STArray s i e -> Int -> e -> STT s m ()

Eq (STArray s i e)

Methods

(==) :: STArray s i e -> STArray s i e -> Bool

(/=) :: STArray s i e -> STArray s i e -> Bool

newSTArray :: (Ix i, Applicative m, Monad m) => (i, i) -> e -> STT s m (STArray s i e)

Creates a new mutable array

readSTArray :: (Ix i, Applicative m, Monad m) => STArray s i e -> i -> STT s m e

Retrieves an element from the array

writeSTArray :: (Ix i, Applicative m, Monad m) => STArray s i e -> i -> e -> STT s m ()

Modifies an element in the array

boundsSTArray :: STArray s i e -> (i, i)

Returns the lowest and highest indices of the array

numElementsSTArray :: STArray s i e -> Int

Returns the number of elements in the array

freezeSTArray :: (Ix i, Applicative m, Monad m) => STArray s i e -> STT s m (Array i e)

Copy a mutable array and turn it into an immutable array

thawSTArray :: (Ix i, Applicative m, Monad m) => Array i e -> STT s m (STArray s i e)

Copy an immutable array and turn it into a mutable array

runSTArray :: (Ix i, Applicative m, Monad m) => (forall s. STT s m (STArray s i e)) -> m (Array i e)

A safe way to create and work with a mutable array before returning an immutable array for later perusal. This function avoids copying the array before returning it.

Unsafe Operations

unsafeIOToSTT :: Monad m => IO a -> STT s m a

unsafeSTToIO :: STT s IO a -> IO a

Deprecated: Use unsafeSTTToIO instead

unsafeSTTToIO :: STT s IO a -> IO a

unsafeSTRefToIORef :: STRef s a -> IORef a

unsafeIORefToSTRef :: IORef a -> STRef s a