| Copyright | Josef Svenningsson 2008-2010 (c) The University of Glasgow 1994-2000 |
|---|---|
| License | BSD |
| Maintainer | josef.svenningsson@gmail.com |
| Stability | experimental |
| Portability | non-portable (GHC Extensions) |
| Safe Haskell | None |
| Language | Haskell98 |
Control.Monad.ST.Trans
Description
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 will be duplicated across the different answers and this cause 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.
- data STT s m a
- runST :: Monad m => (forall s. STT s m a) -> m a
- data STRef s a
- newSTRef :: Monad m => a -> STT s m (STRef s a)
- readSTRef :: Monad m => STRef s a -> STT s m a
- writeSTRef :: Monad m => STRef s a -> a -> STT s m ()
- data STArray s i e
- newSTArray :: (Ix i, Monad m) => (i, i) -> e -> STT s m (STArray s i e)
- readSTArray :: (Ix i, Monad m) => STArray s i e -> i -> STT s m e
- writeSTArray :: (Ix i, Monad m) => STArray s i e -> i -> e -> STT s m ()
- boundsSTArray :: STArray s i e -> (i, i)
- numElementsSTArray :: STArray s i e -> Int
- freezeSTArray :: (Ix i, Monad m) => STArray s i e -> STT s m (Array i e)
- thawSTArray :: (Ix i, Monad m) => Array i e -> STT s m (STArray s i e)
- runSTArray :: (Ix i, Monad m) => (forall s. STT s m (STArray s i e)) -> m (Array i e)
- unsafeIOToSTT :: Monad m => IO a -> STT s m a
- unsafeSTToIO :: STT s IO a -> IO a
- unsafeSTRefToIORef :: STRef s a -> IORef a
- unsafeIORefToSTRef :: IORef a -> STRef s a
The ST Monad Transformer
runST :: Monad m => (forall s. STT s m a) -> m a Source #
Executes a computation in the STT monad transformer
Mutable references
Mutable arrays
newSTArray :: (Ix i, Monad m) => (i, i) -> e -> STT s m (STArray s i e) Source #
Creates a new mutable array
readSTArray :: (Ix i, Monad m) => STArray s i e -> i -> STT s m e Source #
Retrieves an element from the array
writeSTArray :: (Ix i, Monad m) => STArray s i e -> i -> e -> STT s m () Source #
Modifies an element in the array
boundsSTArray :: STArray s i e -> (i, i) Source #
Returns the lowest and highest indices of the array
numElementsSTArray :: STArray s i e -> Int Source #
Returns the number of elements in the array
freezeSTArray :: (Ix i, Monad m) => STArray s i e -> STT s m (Array i e) Source #
Copy a mutable array and turn it into an immutable array
thawSTArray :: (Ix i, Monad m) => Array i e -> STT s m (STArray s i e) Source #
Copy an immutable array and turn it into a mutable array
runSTArray :: (Ix i, Monad m) => (forall s. STT s m (STArray s i e)) -> m (Array i e) Source #
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
unsafeSTRefToIORef :: STRef s a -> IORef a Source #
unsafeIORefToSTRef :: IORef a -> STRef s a Source #
Orphan instances
| MonadError e m => MonadError e (STT s m) Source # | |
| MonadReader r m => MonadReader r (STT s m) Source # | |
| MonadState s m => MonadState s (STT s' m) Source # | |
| MonadWriter w m => MonadWriter w (STT s m) Source # | |
| Functor (STTRet s) Source # | |
| MonadTrans (STT s) Source # | |
| Monad m => Monad (STT s m) Source # | |
| Functor m => Functor (STT s m) Source # | |
| MonadFix m => MonadFix (STT s m) Source # | |
| (Monad m, Functor m) => Applicative (STT s m) Source # | |