Safe Haskell	None
Language	Haskell2010

Polysemy.Resource

Contents

Effect
Actions
Interpretations

Synopsis

data Resource m a where
- Bracket :: m a -> (a -> m ()) -> (a -> m b) -> Resource m b
bracket :: forall a b. forall r. Member Resource r => Semantic r a -> (a -> Semantic r ()) -> (a -> Semantic r b) -> Semantic r b
runResource :: forall r a. Member (Lift IO) r => (forall x. Semantic r x -> IO x) -> Semantic (Resource ': r) a -> Semantic r a

Effect

data Resource m a where Source #

An effect capable of providing bracket semantic. Interpreters for this will successfully run the deallocation action even in the presence of other short-circuiting effects.

Constructors

Bracket
Fields :: m a Action to allocate a resource. -> (a -> m ()) Action to cleanup the resource. This is guaranteed to be called. -> (a -> m b) Action which uses the resource. -> Resource m b

Instances

type DefiningModule Resource Source #
Instance details Defined in Polysemy.Resource type DefiningModule Resource = "Polysemy.Resource"

Actions

bracket :: forall a b. forall r. Member Resource r => Semantic r a -> (a -> Semantic r ()) -> (a -> Semantic r b) -> Semantic r b Source #

Interpretations

runResource Source #

Arguments

:: Member (Lift IO) r
=> (forall x. Semantic r x -> IO x)	Strategy for lowering a `Semantic` action down to `IO`. This is likely some combination of `runM` and other interpters composed via `.@`.
-> Semantic (Resource ': r) a
-> Semantic r a

Run a Resource effect via in terms of bracket.