monad-stlike-io-0.1: ST-like monad capturing variables to regions and supporting IO. Source code Contents Index

Control.Monad.STLike.IO

Contents IOS monad Regioned monad Utilities

Synopsis

type IOS s t = STLike IO s t io :: IO t -> IOS s t runIOS :: (forall s. IOS s t) -> IO t data Regioned s t runRegion :: (NotShared ty, STLikeImpl m) => Regioned s ty -> STLike m s ty region :: t -> Regioned s t rbsFromPtr :: Ptr a -> Int -> IOS s (Regioned s ByteString) rbsToBS :: STLikeImpl m => Regioned s ByteString -> STLike m s ByteString withRbsPtr :: Regioned s ByteString -> (Ptr any -> Int -> IOS s t) -> IOS s t rbsMapLookup :: (STLikeImpl m, Ord key) => Regioned s key -> Map key value -> STLike m s (Maybe value)

IOS monad

type IOS s t = STLike IO s t Source

Monad for scoped IO computations The underlying monad must be strict here.

io :: IO t -> IOS s t Source

Lift IO computations into IOS. liftIO also works.

runIOS :: (forall s. IOS s t) -> IO t Source

Run an IOS computation in the IO monad.

Regioned monad

data Regioned s t Source

Regioned variables. A regioned variable is safe i.e. no references to it may escape the current IOS. Instances Monad (Regioned s) Functor (Regioned s)

runRegion :: (NotShared ty, STLikeImpl m) => Regioned s ty -> STLike m s ty Source

Run a computation on regioned data and return the result in a strict fashion.

region :: t -> Regioned s t Source

Regions a value. Synonym for return.

Utilities

rbsFromPtr :: Ptr a -> Int -> IOS s (Regioned s ByteString) Source

Create a ByteString representing the pointer and length. No copying done, O(1).

rbsToBS :: STLikeImpl m => Regioned s ByteString -> STLike m s ByteString Source

Create a copy of a regioned ByteString as a normal ByteString. O(n).

withRbsPtr :: Regioned s ByteString -> (Ptr any -> Int -> IOS s t) -> IOS s t Source

Use a regioned ByteString as a pointer. O(1). The pointer points to the region contents, so be cafeful with it.

rbsMapLookup :: (STLikeImpl m, Ord key) => Regioned s key -> Map key value -> STLike m s (Maybe value) Source

Lookup inside a Map with a regioned ByteString.

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