Control.Effect.Fail

Fail effect

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

Constructors

Fail String

Instances

Effect Fail

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)

HFunctor Fail

Defined in Control.Effect.Fail

Methods

fmap' :: forall (f :: Type -> Type) a b. Functor (Fail f) => (a -> b) -> Fail f a -> Fail f b

hmap :: Functor m => (forall x. m x -> n x) -> Fail m a -> Fail n a

Functor (Fail m)

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)

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)

Defined in Control.Effect.Fail

Methods

eff :: (Fail :+: sig) (FailC m) a -> FailC m a

type Rep1 (Fail m :: Type -> Type)

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)

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

Constructors

FailC

Fields

• runFailC :: ErrorC String m a

Instances

MonadTrans FailC

Defined in Control.Effect.Fail

Methods

lift :: Monad m => m a -> FailC m a

Monad m => Monad (FailC m)

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)

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)

Defined in Control.Effect.Fail

Methods

mfix :: (a -> FailC m a) -> FailC m a

(Carrier sig m, Effect sig) => MonadFail (FailC m)

Defined in Control.Effect.Fail

Methods

fail :: String -> FailC m a

Applicative m => Applicative (FailC m)

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)

Defined in Control.Effect.Fail

Methods

liftIO :: IO a -> FailC m a

Alternative m => Alternative (FailC m)

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)

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)

Defined in Control.Effect.Fail

Methods

eff :: (Fail :+: sig) (FailC m) a -> FailC m a

Re-exports

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

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

Defined in Control.Effect.Carrier

Methods

eff :: Pure PureC a -> PureC a

(HFunctor eff, Carrier sig m, Member eff sig) => Carrier sig (InterposeC eff m)

Defined in Control.Effect.Interpose

Methods

eff :: sig (InterposeC eff m) a -> InterposeC eff m a

Monad m => Carrier (Lift m) (LiftC m)

Defined in Control.Effect.Lift

Methods

eff :: Lift m (LiftC m) a -> LiftC m a

(Carrier sig m, MonadIO m) => Carrier (Resource :+: sig) (ResourceC m)

Defined in Control.Effect.Resource

Methods

eff :: (Resource :+: sig) (ResourceC m) a -> ResourceC m a

(Carrier sig m, Effect sig) => Carrier (NonDet :+: sig) (NonDetC m)

Defined in Control.Effect.NonDet

Methods

eff :: (NonDet :+: sig) (NonDetC m) a -> NonDetC m a

(Carrier sig m, Effect sig) => Carrier (NonDet :+: sig) (OnceC m)

Defined in Control.Effect.Cull

Methods

eff :: (NonDet :+: sig) (OnceC m) a -> OnceC m a

(Carrier sig m, Effect sig) => Carrier (Fresh :+: sig) (FreshC m)

Defined in Control.Effect.Fresh

Methods

eff :: (Fresh :+: sig) (FreshC m) a -> FreshC m a

(Carrier sig m, Effect sig) => Carrier (Fail :+: sig) (FailC m)

Defined in Control.Effect.Fail

Methods

eff :: (Fail :+: sig) (FailC m) a -> FailC m a

(Carrier sig m, Effect sig) => Carrier (Cut :+: (NonDet :+: sig)) (CutC m)

Defined in Control.Effect.Cut

Methods

eff :: (Cut :+: (NonDet :+: sig)) (CutC m) a -> CutC m a

(Carrier sig m, Effect sig) => Carrier (Cull :+: (NonDet :+: sig)) (CullC m)

Defined in Control.Effect.Cull

Methods

eff :: (Cull :+: (NonDet :+: sig)) (CullC m) a -> CullC m a

(Carrier sig m, Effect sig) => Carrier (Trace :+: sig) (TraceByReturningC m)

Defined in Control.Effect.Trace

Methods

eff :: (Trace :+: sig) (TraceByReturningC m) a -> TraceByReturningC m a

Carrier sig m => Carrier (Trace :+: sig) (TraceByIgnoringC m)

Defined in Control.Effect.Trace

Methods

eff :: (Trace :+: sig) (TraceByIgnoringC m) a -> TraceByIgnoringC m a

(MonadIO m, Carrier sig m) => Carrier (Trace :+: sig) (TraceByPrintingC m)

Defined in Control.Effect.Trace

Methods

eff :: (Trace :+: sig) (TraceByPrintingC m) a -> TraceByPrintingC m a

(HFunctor eff, Carrier sig m) => Carrier (eff :+: sig) (InterpretC eff m)

Defined in Control.Effect.Interpret

Methods

eff :: (eff :+: sig) (InterpretC eff m) a -> InterpretC eff m a

(Carrier sig m, Effect sig) => Carrier (State s :+: sig) (StateC s m)

Defined in Control.Effect.State.Strict

Methods

eff :: (State s :+: sig) (StateC s m) a -> StateC s m a

(Carrier sig m, Effect sig) => Carrier (State s :+: sig) (StateC s m)

Defined in Control.Effect.State.Lazy

Methods

eff :: (State s :+: sig) (StateC s m) a -> StateC s m a

Carrier sig m => Carrier (Reader r :+: sig) (ReaderC r m)

Defined in Control.Effect.Reader

Methods

eff :: (Reader r :+: sig) (ReaderC r m) a -> ReaderC r m a

(Carrier sig m, Effect sig, RandomGen g) => Carrier (Random :+: sig) (RandomC g m)

Defined in Control.Effect.Random

Methods

eff :: (Random :+: sig) (RandomC g m) a -> RandomC g m a

(Carrier sig m, Effect sig) => Carrier (Error e :+: sig) (ErrorC e m)

Defined in Control.Effect.Error

Methods

eff :: (Error e :+: sig) (ErrorC e m) a -> ErrorC e m a

Carrier sig m => Carrier (Resumable err :+: sig) (ResumableWithC err m)

Defined in Control.Effect.Resumable

Methods

eff :: (Resumable err :+: sig) (ResumableWithC err m) a -> ResumableWithC err m a

(Carrier sig m, Effect sig) => Carrier (Resumable err :+: sig) (ResumableC err m)

Defined in Control.Effect.Resumable

Methods

eff :: (Resumable err :+: sig) (ResumableC err m) a -> ResumableC err m a

(Monoid w, Carrier sig m, Effect sig) => Carrier (Writer w :+: sig) (WriterC w m)

Defined in Control.Effect.Writer

Methods

eff :: (Writer w :+: sig) (WriterC w m) a -> WriterC w m a

(HFunctor eff, Carrier sig m, Effect sig) => Carrier (eff :+: sig) (InterpretStateC eff s m)

Defined in Control.Effect.Interpret

Methods

eff :: (eff :+: sig) (InterpretStateC eff s m) a -> InterpretStateC eff s m a

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

Minimal complete definition

inj, prj

Instances

Member sub sub

Defined in Control.Effect.Sum

Methods

inj :: forall (m :: Type -> Type) a. sub m a -> sub m a

prj :: forall (m :: Type -> Type) a. sub m a -> Maybe (sub m a)

Member sub sup => Member sub (sub' :+: sup)

Defined in Control.Effect.Sum

Methods

inj :: forall (m :: Type -> Type) a. sub m a -> (sub' :+: sup) m a

prj :: forall (m :: Type -> Type) a. (sub' :+: sup) m a -> Maybe (sub m a)

Member sub (sub :+: sup)

Defined in Control.Effect.Sum

Methods

inj :: forall (m :: Type -> Type) a. sub m a -> (sub :+: sup) m a

prj :: forall (m :: Type -> Type) a. (sub :+: sup) m a -> Maybe (sub m a)

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

Defined in Control.Monad.Fail

Methods

fail :: String -> [a]

MonadFail Maybe

Since: base-4.9.0.0

Defined in Control.Monad.Fail

Methods

fail :: String -> Maybe a

MonadFail IO

Since: base-4.9.0.0

Defined in Control.Monad.Fail

Methods

fail :: String -> IO a

MonadFail ReadP

Since: base-4.9.0.0

Defined in Text.ParserCombinators.ReadP

Methods

fail :: String -> ReadP a

MonadFail P

Since: base-4.9.0.0

Defined in Text.ParserCombinators.ReadP

Methods

fail :: String -> P a

MonadFail (ST s)

Since: base-4.11.0.0

Defined in GHC.ST

Methods

fail :: String -> ST s a

MonadFail m => MonadFail (ResourceC m)

Defined in Control.Effect.Resource

Methods

fail :: String -> ResourceC m a

MonadFail m => MonadFail (NonDetC m)

Defined in Control.Effect.NonDet

Methods

fail :: String -> NonDetC m a

MonadFail m => MonadFail (LiftC m)

Defined in Control.Effect.Lift

Methods

fail :: String -> LiftC m a

MonadFail m => MonadFail (FreshC m)

Defined in Control.Effect.Fresh

Methods

fail :: String -> FreshC m a

(Carrier sig m, Effect sig) => MonadFail (FailC m)

Defined in Control.Effect.Fail

Methods

fail :: String -> FailC m a

MonadFail m => MonadFail (CutC m)

Defined in Control.Effect.Cut

Methods

fail :: String -> CutC m a

MonadFail m => MonadFail (OnceC m)

Defined in Control.Effect.Cull

Methods

fail :: String -> OnceC m a

MonadFail m => MonadFail (CullC m)

Defined in Control.Effect.Cull

Methods

fail :: String -> CullC m a

MonadFail m => MonadFail (TraceByReturningC m)

Defined in Control.Effect.Trace

Methods

fail :: String -> TraceByReturningC m a

MonadFail m => MonadFail (TraceByIgnoringC m)

Defined in Control.Effect.Trace

Methods

fail :: String -> TraceByIgnoringC m a

MonadFail m => MonadFail (TraceByPrintingC m)

Defined in Control.Effect.Trace

Methods

fail :: String -> TraceByPrintingC m a

MonadFail f => MonadFail (Ap f)

Since: base-4.12.0.0

Defined in Data.Monoid

Methods

fail :: String -> Ap f a

MonadFail m => MonadFail (IdentityT m)

Defined in Control.Monad.Trans.Identity

Methods

fail :: String -> IdentityT m a

(Monad m, Error e) => MonadFail (ErrorT e m)

Defined in Control.Monad.Trans.Error

Methods

fail :: String -> ErrorT e m a

MonadFail m => MonadFail (ReaderT r m)

Defined in Control.Monad.Trans.Reader

Methods

fail :: String -> ReaderT r m a

MonadFail m => MonadFail (StateC s m)

Defined in Control.Effect.State.Strict

Methods

fail :: String -> StateC s m a

MonadFail m => MonadFail (StateC s m)

Defined in Control.Effect.State.Lazy

Methods

fail :: String -> StateC s m a

MonadFail m => MonadFail (ReaderC r m)

Defined in Control.Effect.Reader

Methods

fail :: String -> ReaderC r m a

MonadFail m => MonadFail (RandomC g m)

Defined in Control.Effect.Random

Methods

fail :: String -> RandomC g m a

MonadFail m => MonadFail (InterpretC eff m)

Defined in Control.Effect.Interpret

Methods

fail :: String -> InterpretC eff m a

MonadFail m => MonadFail (InterposeC eff m)

Defined in Control.Effect.Interpose

Methods

fail :: String -> InterposeC eff m a

MonadFail m => MonadFail (ErrorC e m)

Defined in Control.Effect.Error

Methods

fail :: String -> ErrorC e m a

MonadFail m => MonadFail (ResumableWithC err m)

Defined in Control.Effect.Resumable

Methods

fail :: String -> ResumableWithC err m a

MonadFail m => MonadFail (ResumableC err m)

Defined in Control.Effect.Resumable

Methods

fail :: String -> ResumableC err m a

MonadFail m => MonadFail (WriterC w m)

Defined in Control.Effect.Writer

Methods

fail :: String -> WriterC w m a

MonadFail m => MonadFail (InterpretStateC eff s m)

Defined in Control.Effect.Interpret

Methods

fail :: String -> InterpretStateC eff s m a

run :: PureC a -> a

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