Safe Haskell	None
Language	Haskell2010

Control.Effect.Fail

Contents

Fail effect
Fail carrier
Re-exports

Synopsis

newtype Fail (m :: * -> *) k = Fail String
runFail :: FailC m a -> m (Either String a)
newtype FailC m a = FailC {
- runFailC :: ErrorC String m a
}
class (HFunctor sig, Monad m) => Carrier sig m | m -> sig
class Member (sub :: (* -> *) -> * -> *) sup
class Monad m => MonadFail (m :: Type -> Type) where
- fail :: String -> m a
run :: PureC a -> a

Fail effect

newtype Fail (m :: * -> *) k Source #

Constructors

Fail String

Instances

Instances details

Effect Fail Source #
Instance details Defined in Control.Effect.Fail Methods handle :: (Functor f, Monad m) => f () -> (forall x. f (m x) -> n (f x)) -> Fail m a -> Fail n (f a) Source #
HFunctor Fail Source #
Instance details Defined in Control.Effect.Fail Methods fmap' :: forall (f :: Type -> Type) a b. Functor (Fail f) => (a -> b) -> Fail f a -> Fail f b Source # hmap :: Functor m => (forall x. m x -> n x) -> Fail m a -> Fail n a Source #
Functor (Fail m) Source #
Instance details Defined in Control.Effect.Fail Methods fmap :: (a -> b) -> Fail m a -> Fail m b # (<$) :: a -> Fail m b -> Fail m a #
Generic1 (Fail m :: Type -> Type) Source #
Instance details Defined in Control.Effect.Fail Associated Types type Rep1 (Fail m) :: k -> Type # Methods from1 :: forall (a :: k). Fail m a -> Rep1 (Fail m) a # to1 :: forall (a :: k). Rep1 (Fail m) a -> Fail m a #
(Carrier sig m, Effect sig) => Carrier (Fail :+: sig) (FailC m) Source #
Instance details Defined in Control.Effect.Fail Methods eff :: (Fail :+: sig) (FailC m) a -> FailC m a Source #
type Rep1 (Fail m :: Type -> Type) Source #
Instance details Defined in Control.Effect.Fail type Rep1 (Fail m :: Type -> Type) = D1 ('MetaData "Fail" "Control.Effect.Fail" "fused-effects-0.5.0.1-inplace" 'True) (C1 ('MetaCons "Fail" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 String)))

Fail carrier

runFail :: FailC m a -> m (Either String a) Source #

Run a Fail effect, returning failure messages in Left and successful computations’ results in Right.

run (runFail (pure a)) === Right a

newtype FailC m a Source #

Constructors

FailC
Fields runFailC :: ErrorC String m a

Instances

Instances details

MonadTrans FailC Source #
Instance details Defined in Control.Effect.Fail Methods lift :: Monad m => m a -> FailC m a #
Monad m => Monad (FailC m) Source #
Instance details Defined in Control.Effect.Fail Methods (>>=) :: FailC m a -> (a -> FailC m b) -> FailC m b # (>>) :: FailC m a -> FailC m b -> FailC m b # return :: a -> FailC m a #
Functor m => Functor (FailC m) Source #
Instance details Defined in Control.Effect.Fail Methods fmap :: (a -> b) -> FailC m a -> FailC m b # (<$) :: a -> FailC m b -> FailC m a #
MonadFix m => MonadFix (FailC m) Source #
Instance details Defined in Control.Effect.Fail Methods mfix :: (a -> FailC m a) -> FailC m a #
(Carrier sig m, Effect sig) => MonadFail (FailC m) Source #
Instance details Defined in Control.Effect.Fail Methods fail :: String -> FailC m a #
Applicative m => Applicative (FailC m) Source #
Instance details Defined in Control.Effect.Fail Methods pure :: a -> FailC m a # (<>) :: FailC m (a -> b) -> FailC m a -> FailC m b # liftA2 :: (a -> b -> c) -> FailC m a -> FailC m b -> FailC m c # (>) :: FailC m a -> FailC m b -> FailC m b # (<*) :: FailC m a -> FailC m b -> FailC m a #
MonadIO m => MonadIO (FailC m) Source #
Instance details Defined in Control.Effect.Fail Methods liftIO :: IO a -> FailC m a #
Alternative m => Alternative (FailC m) Source #
Instance details Defined in Control.Effect.Fail Methods empty :: FailC m a # (<\|>) :: FailC m a -> FailC m a -> FailC m a # some :: FailC m a -> FailC m [a] # many :: FailC m a -> FailC m [a] #
(Alternative m, Monad m) => MonadPlus (FailC m) Source #
Instance details Defined in Control.Effect.Fail Methods mzero :: FailC m a # mplus :: FailC m a -> FailC m a -> FailC m a #
(Carrier sig m, Effect sig) => Carrier (Fail :+: sig) (FailC m) Source #
Instance details Defined in Control.Effect.Fail Methods eff :: (Fail :+: sig) (FailC m) a -> FailC m a Source #

Re-exports

class (HFunctor sig, Monad m) => Carrier sig m | m -> sig Source #

The class of carriers (results) for algebras (effect handlers) over signatures (effects), whose actions are given by the eff method.

Minimal complete definition

eff

Instances

Instances details

Carrier Pure PureC Source #
Instance details Defined in Control.Effect.Carrier Methods eff :: Pure PureC a -> PureC a Source #
(HFunctor eff, Carrier sig m, Member eff sig) => Carrier sig (InterposeC eff m) Source #
Instance details Defined in Control.Effect.Interpose Methods eff :: sig (InterposeC eff m) a -> InterposeC eff m a Source #
Monad m => Carrier (Lift m) (LiftC m) Source #
Instance details Defined in Control.Effect.Lift Methods eff :: Lift m (LiftC m) a -> LiftC m a Source #
(Carrier sig m, MonadIO m) => Carrier (Resource :+: sig) (ResourceC m) Source #
Instance details Defined in Control.Effect.Resource Methods eff :: (Resource :+: sig) (ResourceC m) a -> ResourceC m a Source #
(Carrier sig m, Effect sig) => Carrier (NonDet :+: sig) (NonDetC m) Source #
Instance details Defined in Control.Effect.NonDet Methods eff :: (NonDet :+: sig) (NonDetC m) a -> NonDetC m a Source #
(Carrier sig m, Effect sig) => Carrier (NonDet :+: sig) (OnceC m) Source #
Instance details Defined in Control.Effect.Cull Methods eff :: (NonDet :+: sig) (OnceC m) a -> OnceC m a Source #
(Carrier sig m, Effect sig) => Carrier (Fresh :+: sig) (FreshC m) Source #
Instance details Defined in Control.Effect.Fresh Methods eff :: (Fresh :+: sig) (FreshC m) a -> FreshC m a Source #
(Carrier sig m, Effect sig) => Carrier (Fail :+: sig) (FailC m) Source #
Instance details Defined in Control.Effect.Fail Methods eff :: (Fail :+: sig) (FailC m) a -> FailC m a Source #
(Carrier sig m, Effect sig) => Carrier (Cut :+: (NonDet :+: sig)) (CutC m) Source #
Instance details Defined in Control.Effect.Cut Methods eff :: (Cut :+: (NonDet :+: sig)) (CutC m) a -> CutC m a Source #
(Carrier sig m, Effect sig) => Carrier (Cull :+: (NonDet :+: sig)) (CullC m) Source #
Instance details Defined in Control.Effect.Cull Methods eff :: (Cull :+: (NonDet :+: sig)) (CullC m) a -> CullC m a Source #
(Carrier sig m, Effect sig) => Carrier (Trace :+: sig) (TraceByReturningC m) Source #
Instance details Defined in Control.Effect.Trace Methods eff :: (Trace :+: sig) (TraceByReturningC m) a -> TraceByReturningC m a Source #
Carrier sig m => Carrier (Trace :+: sig) (TraceByIgnoringC m) Source #
Instance details Defined in Control.Effect.Trace Methods eff :: (Trace :+: sig) (TraceByIgnoringC m) a -> TraceByIgnoringC m a Source #
(MonadIO m, Carrier sig m) => Carrier (Trace :+: sig) (TraceByPrintingC m) Source #
Instance details Defined in Control.Effect.Trace Methods eff :: (Trace :+: sig) (TraceByPrintingC m) a -> TraceByPrintingC m a Source #
(HFunctor eff, Carrier sig m) => Carrier (eff :+: sig) (InterpretC eff m) Source #
Instance details Defined in Control.Effect.Interpret Methods eff :: (eff :+: sig) (InterpretC eff m) a -> InterpretC eff m a Source #
(Carrier sig m, Effect sig) => Carrier (State s :+: sig) (StateC s m) Source #
Instance details Defined in Control.Effect.State.Strict Methods eff :: (State s :+: sig) (StateC s m) a -> StateC s m a Source #
(Carrier sig m, Effect sig) => Carrier (State s :+: sig) (StateC s m) Source #
Instance details Defined in Control.Effect.State.Lazy Methods eff :: (State s :+: sig) (StateC s m) a -> StateC s m a Source #
Carrier sig m => Carrier (Reader r :+: sig) (ReaderC r m) Source #
Instance details Defined in Control.Effect.Reader Methods eff :: (Reader r :+: sig) (ReaderC r m) a -> ReaderC r m a Source #
(Carrier sig m, Effect sig, RandomGen g) => Carrier (Random :+: sig) (RandomC g m) Source #
Instance details Defined in Control.Effect.Random Methods eff :: (Random :+: sig) (RandomC g m) a -> RandomC g m a Source #
(Carrier sig m, Effect sig) => Carrier (Error e :+: sig) (ErrorC e m) Source #
Instance details Defined in Control.Effect.Error Methods eff :: (Error e :+: sig) (ErrorC e m) a -> ErrorC e m a Source #
Carrier sig m => Carrier (Resumable err :+: sig) (ResumableWithC err m) Source #
Instance details Defined in Control.Effect.Resumable Methods eff :: (Resumable err :+: sig) (ResumableWithC err m) a -> ResumableWithC err m a Source #
(Carrier sig m, Effect sig) => Carrier (Resumable err :+: sig) (ResumableC err m) Source #
Instance details Defined in Control.Effect.Resumable Methods eff :: (Resumable err :+: sig) (ResumableC err m) a -> ResumableC err m a Source #
(Monoid w, Carrier sig m, Effect sig) => Carrier (Writer w :+: sig) (WriterC w m) Source #
Instance details Defined in Control.Effect.Writer Methods eff :: (Writer w :+: sig) (WriterC w m) a -> WriterC w m a Source #
(HFunctor eff, Carrier sig m, Effect sig) => Carrier (eff :+: sig) (InterpretStateC eff s m) Source #
Instance details Defined in Control.Effect.Interpret Methods eff :: (eff :+: sig) (InterpretStateC eff s m) a -> InterpretStateC eff s m a Source #

class Member (sub :: (* -> *) -> * -> *) sup Source #

Minimal complete definition

inj, prj

Instances

Instances details

Member sub sub Source #
Instance details Defined in Control.Effect.Sum Methods inj :: forall (m :: Type -> Type) a. sub m a -> sub m a Source # prj :: forall (m :: Type -> Type) a. sub m a -> Maybe (sub m a) Source #
Member sub sup => Member sub (sub' :+: sup) Source #
Instance details Defined in Control.Effect.Sum Methods inj :: forall (m :: Type -> Type) a. sub m a -> (sub' :+: sup) m a Source # prj :: forall (m :: Type -> Type) a. (sub' :+: sup) m a -> Maybe (sub m a) Source #
Member sub (sub :+: sup) Source #
Instance details Defined in Control.Effect.Sum Methods inj :: forall (m :: Type -> Type) a. sub m a -> (sub :+: sup) m a Source # prj :: forall (m :: Type -> Type) a. (sub :+: sup) m a -> Maybe (sub m a) Source #

class Monad m => MonadFail (m :: Type -> Type) where #

When a value is bound in do-notation, the pattern on the left hand side of <- might not match. In this case, this class provides a function to recover.

A Monad without a MonadFail instance may only be used in conjunction with pattern that always match, such as newtypes, tuples, data types with only a single data constructor, and irrefutable patterns (~pat).

Instances of MonadFail should satisfy the following law: fail s should be a left zero for >>=,

fail s >>= f  =  fail s

If your Monad is also MonadPlus, a popular definition is

fail _ = mzero

Since: base-4.9.0.0

Methods

fail :: String -> m a #

Instances

Instances details

MonadFail []	Since: base-4.9.0.0
Instance details Defined in Control.Monad.Fail Methods fail :: String -> [a] #
MonadFail Maybe	Since: base-4.9.0.0
Instance details Defined in Control.Monad.Fail Methods fail :: String -> Maybe a #
MonadFail IO	Since: base-4.9.0.0
Instance details Defined in Control.Monad.Fail Methods fail :: String -> IO a #
MonadFail ReadP	Since: base-4.9.0.0
Instance details Defined in Text.ParserCombinators.ReadP Methods fail :: String -> ReadP a #
MonadFail P	Since: base-4.9.0.0
Instance details Defined in Text.ParserCombinators.ReadP Methods fail :: String -> P a #
MonadFail (ST s)	Since: base-4.11.0.0
Instance details Defined in GHC.ST Methods fail :: String -> ST s a #
MonadFail m => MonadFail (ResourceC m) Source #
Instance details Defined in Control.Effect.Resource Methods fail :: String -> ResourceC m a #
MonadFail m => MonadFail (NonDetC m) Source #
Instance details Defined in Control.Effect.NonDet Methods fail :: String -> NonDetC m a #
MonadFail m => MonadFail (LiftC m) Source #
Instance details Defined in Control.Effect.Lift Methods fail :: String -> LiftC m a #
MonadFail m => MonadFail (FreshC m) Source #
Instance details Defined in Control.Effect.Fresh Methods fail :: String -> FreshC m a #
(Carrier sig m, Effect sig) => MonadFail (FailC m) Source #
Instance details Defined in Control.Effect.Fail Methods fail :: String -> FailC m a #
MonadFail m => MonadFail (CutC m) Source #
Instance details Defined in Control.Effect.Cut Methods fail :: String -> CutC m a #
MonadFail m => MonadFail (OnceC m) Source #
Instance details Defined in Control.Effect.Cull Methods fail :: String -> OnceC m a #
MonadFail m => MonadFail (CullC m) Source #
Instance details Defined in Control.Effect.Cull Methods fail :: String -> CullC m a #
MonadFail m => MonadFail (TraceByReturningC m) Source #
Instance details Defined in Control.Effect.Trace Methods fail :: String -> TraceByReturningC m a #
MonadFail m => MonadFail (TraceByIgnoringC m) Source #
Instance details Defined in Control.Effect.Trace Methods fail :: String -> TraceByIgnoringC m a #
MonadFail m => MonadFail (TraceByPrintingC m) Source #
Instance details Defined in Control.Effect.Trace Methods fail :: String -> TraceByPrintingC m a #
MonadFail f => MonadFail (Ap f)	Since: base-4.12.0.0
Instance details Defined in Data.Monoid Methods fail :: String -> Ap f a #
MonadFail m => MonadFail (IdentityT m)
Instance details Defined in Control.Monad.Trans.Identity Methods fail :: String -> IdentityT m a #
(Monad m, Error e) => MonadFail (ErrorT e m)
Instance details Defined in Control.Monad.Trans.Error Methods fail :: String -> ErrorT e m a #
MonadFail m => MonadFail (ReaderT r m)
Instance details Defined in Control.Monad.Trans.Reader Methods fail :: String -> ReaderT r m a #
MonadFail m => MonadFail (StateC s m) Source #
Instance details Defined in Control.Effect.State.Strict Methods fail :: String -> StateC s m a #
MonadFail m => MonadFail (StateC s m) Source #
Instance details Defined in Control.Effect.State.Lazy Methods fail :: String -> StateC s m a #
MonadFail m => MonadFail (ReaderC r m) Source #
Instance details Defined in Control.Effect.Reader Methods fail :: String -> ReaderC r m a #
MonadFail m => MonadFail (RandomC g m) Source #
Instance details Defined in Control.Effect.Random Methods fail :: String -> RandomC g m a #
MonadFail m => MonadFail (InterpretC eff m) Source #
Instance details Defined in Control.Effect.Interpret Methods fail :: String -> InterpretC eff m a #
MonadFail m => MonadFail (InterposeC eff m) Source #
Instance details Defined in Control.Effect.Interpose Methods fail :: String -> InterposeC eff m a #
MonadFail m => MonadFail (ErrorC e m) Source #
Instance details Defined in Control.Effect.Error Methods fail :: String -> ErrorC e m a #
MonadFail m => MonadFail (ResumableWithC err m) Source #
Instance details Defined in Control.Effect.Resumable Methods fail :: String -> ResumableWithC err m a #
MonadFail m => MonadFail (ResumableC err m) Source #
Instance details Defined in Control.Effect.Resumable Methods fail :: String -> ResumableC err m a #
MonadFail m => MonadFail (WriterC w m) Source #
Instance details Defined in Control.Effect.Writer Methods fail :: String -> WriterC w m a #
MonadFail m => MonadFail (InterpretStateC eff s m) Source #
Instance details Defined in Control.Effect.Interpret Methods fail :: String -> InterpretStateC eff s m a #

run :: PureC a -> a Source #

Run an action exhausted of effects to produce its final result value.