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GHC.STRef Portability non-portable (GHC Extensions) Stability internal Maintainer cvs-ghc@haskell.org

Description

References in the ST monad.

Synopsis

data STRef s a = STRef (MutVar# s a) newSTRef :: a -> ST s (STRef s a) readSTRef :: STRef s a -> ST s a writeSTRef :: STRef s a -> a -> ST s () modifySTRef :: STRef s a -> (a -> a) -> ST s ()

Documentation

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 Constructors STRef (MutVar# s a) Instances (Typeable a, Typeable b) => Typeable (STRef a b) Eq (STRef s a)

newSTRef :: a -> ST s (STRef s a)

Build a new STRef in the current state thread

readSTRef :: STRef s a -> ST s a

Read the value of an STRef

writeSTRef :: STRef s a -> a -> ST s ()

Write a new value into an STRef

modifySTRef :: STRef s a -> (a -> a) -> ST s ()

Mutate the contents of an STRef

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