Copyright	(c) Michael Szvetits 2023
License	BSD-3-Clause (see the file LICENSE)
Maintainer	typedbyte@qualified.name
Stability	stable
Portability	portable
Safe Haskell	Safe-Inferred
Language	GHC2021

Effectful.Resource

Contents

Resource Effect
Manage Regions
Manage Resources

Description

A region-based resource effect for the effectful ecosystem.

Synopsis

data Resource :: Effect
runResource :: IOE :> es => Eff (Resource ': es) a -> Eff es a
data Region
withRegion :: Resource :> es => Eff es a -> Eff es a
currentRegion :: Resource :> es => Eff es Region
data Key
data InvalidKey = InvalidKey
manage :: Resource :> es => IO a -> (a -> IO b) -> Eff es a
allocate :: Resource :> es => IO a -> (a -> IO b) -> Eff es (a, Key)
free :: Key -> Eff es ()
freeAll :: Foldable t => t Key -> Eff es ()
move :: Resource :> es => Key -> Region -> Eff es Key
move_ :: Resource :> es => Key -> Region -> Eff es ()
defer :: Resource :> es => IO a -> Eff es ()

Resource Effect

data Resource :: Effect Source #

The region-based resource effect.

Instances

Instances details

type DispatchOf Resource Source #
Instance details Defined in Effectful.Resource type DispatchOf Resource = 'Static 'WithSideEffects
newtype StaticRep Resource Source #
Instance details Defined in Effectful.Resource newtype StaticRep Resource = Resource Region

runResource :: IOE :> es => Eff (Resource ': es) a -> Eff es a Source #

Runs the resource effect.

Manage Regions

data Region Source #

A region owns resources and frees them on close.

Instances

Instances details

Eq Region Source #
Instance details Defined in Effectful.Resource Methods (==) :: Region -> Region -> Bool # (/=) :: Region -> Region -> Bool #

withRegion :: Resource :> es => Eff es a -> Eff es a Source #

Runs a computation in a new region.

currentRegion :: Resource :> es => Eff es Region Source #

Gets the current region.

Manage Resources

data Key Source #

Each resource is identified by a unique key.

Instances

Instances details

Eq Key Source #
Instance details Defined in Effectful.Resource Methods (==) :: Key -> Key -> Bool # (/=) :: Key -> Key -> Bool #

data InvalidKey Source #

An error which occurs if a key is freed/moved that has already been freed/moved.

Constructors

InvalidKey

Instances

Instances details

Exception InvalidKey Source #
Instance details Defined in Effectful.Resource Methods toException :: InvalidKey -> SomeException # fromException :: SomeException -> Maybe InvalidKey # displayException :: InvalidKey -> String #
Show InvalidKey Source #
Instance details Defined in Effectful.Resource Methods showsPrec :: Int -> InvalidKey -> ShowS # show :: InvalidKey -> String # showList :: [InvalidKey] -> ShowS #
Eq InvalidKey Source #
Instance details Defined in Effectful.Resource Methods (==) :: InvalidKey -> InvalidKey -> Bool # (/=) :: InvalidKey -> InvalidKey -> Bool #
Ord InvalidKey Source #
Instance details Defined in Effectful.Resource Methods compare :: InvalidKey -> InvalidKey -> Ordering # (<) :: InvalidKey -> InvalidKey -> Bool # (<=) :: InvalidKey -> InvalidKey -> Bool # (>) :: InvalidKey -> InvalidKey -> Bool # (>=) :: InvalidKey -> InvalidKey -> Bool # max :: InvalidKey -> InvalidKey -> InvalidKey # min :: InvalidKey -> InvalidKey -> InvalidKey #

manage Source #

Arguments

:: Resource :> es
=> IO a	The computation which acquires the resource.
-> (a -> IO b)	The computation which releases the resource.
-> Eff es a	The acquired resource.

Allocates a resource in the current region which is automatically freed at the end of the region.

allocate Source #

Arguments

:: Resource :> es
=> IO a	The computation which acquires the resource.
-> (a -> IO b)	The computation which releases the resource.
-> Eff es (a, Key)	The acquired resource and its corresponding key.

Allocates a resource in the current region which can be moved and freed manually using its key.

free :: Key -> Eff es () Source #

Frees a resource manually.

freeAll :: Foldable t => t Key -> Eff es () Source #

Frees a collection of resources manually.

move :: Resource :> es => Key -> Region -> Eff es Key Source #

Moves a resource to the specified region, yielding a new key for the resource. The old key is invalid after the movement.

move_ :: Resource :> es => Key -> Region -> Eff es () Source #

Moves a resource to the specified region. It is freed at the end of this region. The key of the moved resource is invalid after the movement.

defer :: Resource :> es => IO a -> Eff es () Source #

Associats a cleanup action with the current region which is executed when the region is closed.