fused-effects-0.2.0.0: A fast, flexible, fused effect system.

Safe HaskellNone
LanguageHaskell2010

Control.Effect.Resource

Synopsis

Documentation

data Resource m k Source #

Constructors

Resource (m resource) (resource -> m any) (resource -> m output) (output -> k) 
OnError (m resource) (resource -> m any) (resource -> m output) (output -> k) 
Instances
Effect Resource Source # 
Instance details

Defined in Control.Effect.Resource

Methods

handle :: Functor f => f () -> (forall x. f (m x) -> n (f x)) -> Resource m (m a) -> Resource n (n (f a)) Source #

HFunctor Resource Source # 
Instance details

Defined in Control.Effect.Resource

Methods

fmap' :: (a -> b) -> Resource m a -> Resource m b Source #

hmap :: (forall x. m x -> n x) -> Resource m a -> Resource n a Source #

Functor (Resource m) Source # 
Instance details

Defined in Control.Effect.Resource

Methods

fmap :: (a -> b) -> Resource m a -> Resource m b #

(<$) :: a -> Resource m b -> Resource m a #

(Carrier sig m, MonadIO m) => Carrier (Resource :+: sig) (ResourceC m) Source # 
Instance details

Defined in Control.Effect.Resource

Methods

ret :: a -> ResourceC m a Source #

eff :: (Resource :+: sig) (ResourceC m) (ResourceC m a) -> ResourceC m a Source #

bracket Source #

Arguments

:: (Member Resource sig, Carrier sig m) 
=> m resource

computation to run first ("acquire resource")

-> (resource -> m any)

computation to run last ("release resource")

-> (resource -> m a)

computation to run in-between

-> m a 

Provides a safe idiom to acquire and release resources safely.

When acquiring and operating on a resource (such as opening and reading file handle with openFile or writing to a blob of memory with malloc), any exception thrown during the operation may mean that the resource is not properly released. bracket acquire release op ensures that release is run on the value returned from acquire even if op throws an exception.

bracket is safe in the presence of asynchronous exceptions.

bracketOnError Source #

Arguments

:: (Member Resource sig, Carrier sig m) 
=> m resource

computation to run first ("acquire resource")

-> (resource -> m any)

computation to run last ("release resource")

-> (resource -> m a)

computation to run in-between

-> m a 

Like bracket, but only performs the final action if there was an exception raised by the in-between computation.

finally Source #

Arguments

:: (Member Resource sig, Carrier sig m, Applicative m) 
=> m a

computation to run first

-> m b

computation to run afterward (even if an exception was raised)

-> m a 

Like bracket, but for the simple case of one computation to run afterward.

onException Source #

Arguments

:: (Member Resource sig, Carrier sig m, Applicative m) 
=> m a

computation to run first

-> m b

computation to run afterward if an exception was raised

-> m a 

Like bracketOnError, but for the simple case of one computation to run afterward.

runResource :: (Carrier sig m, MonadIO m) => (forall x. m x -> IO x) -> Eff (ResourceC m) a -> m a Source #

newtype ResourceC m a Source #

Constructors

ResourceC ((forall x. m x -> IO x) -> m a) 
Instances
(Carrier sig m, MonadIO m) => Carrier (Resource :+: sig) (ResourceC m) Source # 
Instance details

Defined in Control.Effect.Resource

Methods

ret :: a -> ResourceC m a Source #

eff :: (Resource :+: sig) (ResourceC m) (ResourceC m a) -> ResourceC m a Source #