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| GHC.ST | | Portability | non-portable (GHC Extensions) | | Stability | internal | | Maintainer | cvs-ghc@haskell.org |
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| Description |
| The ST Monad.
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| Synopsis |
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| Documentation |
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| newtype ST s a |
The strict state-transformer monad.
A computation of type ST s a transforms an internal state indexed
by s, and returns a value of type a.
The s parameter is either
- an unstantiated type variable (inside invocations of runST), or
- RealWorld (inside invocations of stToIO).
It serves to keep the internal states of different invocations
of runST separate from each other and from invocations of
stToIO. | | Constructors | | | Instances | |
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| type STRep s a = State# s -> (#State# s, a#) |
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| data STret s a |
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| liftST :: ST s a -> State# s -> STret s a |
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| unsafeInterleaveST :: ST s a -> ST s a |
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| fixST :: (a -> ST s a) -> ST s a |
| Allow the result of a state transformer computation to be used (lazily)
inside the computation.
Note that if f is strict, fixST f = _|_. |
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| runST :: (forall s . ST s a) -> a |
| Return the value computed by a state transformer computation.
The forall ensures that the internal state used by the ST
computation is inaccessible to the rest of the program. |
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| runSTRep :: (forall s . STRep s a) -> a |
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| Produced by Haddock version 0.6 |
