Control.Monad.ST.Persistent

This library provides support for a persistent version of the ST monad. Internally, references are backed by a IntMap, rather than being mutable variables on the heap. This decreases performance, but can be useful in certain settings, particularly those involving backtracking.

The Persistent ST Monad

type ST s = STT s Identity

A persistent version of the ST monad.

runST :: (forall s. ST s a) -> a

Run a computation that uses persistent references, and return a pure value. The rank-2 type offers similar guarantees to runST.

The Persistent ST Monad transformer

data STT s m a

Instances

MonadTrans (STT s)

Monad m => MonadRef (STRef s) (STT s m)

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

Monad m => Monad (STT s m)

Functor m => Functor (STT s m)

MonadPlus m => MonadPlus (STT s m)

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

MonadIO m => MonadIO (STT s m)

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

Run a computation that uses persistent references, and return a pure value. The rank-2 type offers similar guarantees to runST.