primitive-0.3.1: Wrappers for primitive operations Contents Index

Control.Monad.Primitive Portability non-portable Maintainer Roman Leshchinskiy <rl@cse.unsw.edu.au>

Description

Primitive state-transformer monads

Synopsis

class Monad m => PrimMonad m where type PrimState m primitive :: (State# (PrimState m) -> (#State# (PrimState m), a#)) -> m a internal :: m a -> State# (PrimState m) -> (#State# (PrimState m), a#) data RealWorld primitive_ :: PrimMonad m => (State# (PrimState m) -> State# (PrimState m)) -> m () primToPrim :: (PrimMonad m1, PrimMonad m2, PrimState m1 ~ PrimState m2) => m1 a -> m2 a primToIO :: (PrimMonad m, PrimState m ~ RealWorld) => m a -> IO a primToST :: PrimMonad m => m a -> ST (PrimState m) a unsafePrimToPrim :: (PrimMonad m1, PrimMonad m2) => m1 a -> m2 a unsafePrimToIO :: PrimMonad m => m a -> IO a unsafePrimToST :: PrimMonad m => m a -> ST s a unsafeInlinePrim :: PrimMonad m => m a -> a unsafeInlineIO :: IO a -> a unsafeInlineST :: ST s a -> a touch :: PrimMonad m => a -> m ()

Documentation

class Monad m => PrimMonad m where

Class of primitive state-transformer monads Associated Types type PrimState m State token type Methods primitive :: (State# (PrimState m) -> (#State# (PrimState m), a#)) -> m a Execute a primitive operation internal :: m a -> State# (PrimState m) -> (#State# (PrimState m), a#) Expose the internal structure of the monad Instances PrimMonad IO PrimMonad (ST s)

data RealWorld

RealWorld is deeply magical. It is primitive, but it is not unlifted (hence ptrArg). We never manipulate values of type RealWorld; it's only used in the type system, to parameterise State#. Instances Typeable RealWorld

primitive_ :: PrimMonad m => (State# (PrimState m) -> State# (PrimState m)) -> m ()

Execute a primitive operation with no result

primToPrim :: (PrimMonad m1, PrimMonad m2, PrimState m1 ~ PrimState m2) => m1 a -> m2 a

Convert a PrimMonad to another monad with the same state token.

primToIO :: (PrimMonad m, PrimState m ~ RealWorld) => m a -> IO a

Convert a PrimMonad with a RealWorld state token to IO

primToST :: PrimMonad m => m a -> ST (PrimState m) a

Convert a PrimMonad to ST

unsafePrimToPrim :: (PrimMonad m1, PrimMonad m2) => m1 a -> m2 a

Convert a PrimMonad to another monad with a possibly different state token. This operation is highly unsafe!

unsafePrimToIO :: PrimMonad m => m a -> IO a

Convert any PrimMonad to IO. This operation is highly unsafe!

unsafePrimToST :: PrimMonad m => m a -> ST s a

Convert any PrimMonad to ST with an arbitrary state token. This operations is highly unsafe!

unsafeInlinePrim :: PrimMonad m => m a -> a

unsafeInlineIO :: IO a -> a

unsafeInlineST :: ST s a -> a

touch :: PrimMonad m => a -> m ()

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