Polysemy.Resource

Effect

data Resource m a where

An effect capable of providing bracket semantics. 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

Defined in Polysemy.Resource

type DefiningModule Resource = "Polysemy.Resource"

Actions

bracket :: forall r a a. Member Resource r => Sem r a -> (a -> Sem r ()) -> (a -> Sem r a) -> Sem r a

Interpretations

runResource

Arguments

:: Member (Lift IO) r

=> (forall x. Sem r x -> IO x)

Strategy for lowering a Sem action down to IO. This is likely some combination of runM and other interpreters composed via .@.

-> Sem (Resource ': r) a

-> Sem r a

Run a Resource effect via in terms of bracket.