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

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' :: 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 :: Fail m a -> Rep1 (Fail m) a # to1 :: 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-0.5.0.0-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

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 # fail :: String -> 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

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

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

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.