Safe Haskell	None
Language	Haskell2010

Polysemy.Error

Contents

Synopsis

data Error e m a where
- Throw :: e -> Error e m a
- Catch :: forall e m a. m a -> (e -> m a) -> Error e m a
throw :: forall e a. forall r. Member (Error e) r => e -> Semantic r a
catch :: forall e a. forall r. Member (Error e) r => Semantic r a -> (e -> Semantic r a) -> Semantic r a
runError :: Typeable e => Semantic (Error e ': r) a -> Semantic r (Either e a)
runErrorInIO :: (Typeable e, Member (Lift IO) r) => (forall x. Semantic r x -> IO x) -> Semantic (Error e ': r) a -> Semantic r (Either e a)

Effect

data Error e m a where Source #

Constructors

Throw :: e -> Error e m a
Catch :: forall e m a. m a -> (e -> m a) -> Error e m a

Instances

type DefiningModule (Error :: Type -> (k -> Type) -> k -> Type) Source #
Instance details Defined in Polysemy.Error type DefiningModule (Error :: Type -> (k -> Type) -> k -> Type) = "Polysemy.Error"

Actions

throw :: forall e a. forall r. Member (Error e) r => e -> Semantic r a Source #

catch :: forall e a. forall r. Member (Error e) r => Semantic r a -> (e -> Semantic r a) -> Semantic r a Source #

Run an Error effect in the style of ExceptT.

Arguments

:: (Typeable e, 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 (Error e ': r) a
-> Semantic r (Either e a)

Run an Error effect as an IO Exception. This interpretation is significantly faster than runError, at the cost of being less flexible.