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

data ST s a

A persistent version of the ST monad.

Instances

Monad (ST s)

Functor (ST s)

Applicative (ST s)

MonadRef (STRef s) (ST s)

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.