Safe Haskell	Safe-Inferred
Language	Haskell2010

Control.Monad.Ology.Specific.ExceptT

Contents

Orphan instances

Synopsis

mapExcept :: (Either e a -> Either e' b) -> Except e a -> Except e' b
mapExceptT :: (m (Either e a) -> n (Either e' b)) -> ExceptT e m a -> ExceptT e' n b
runExcept :: Except e a -> Either e a
runExceptT :: ExceptT e m a -> m (Either e a)
withExcept :: (e -> e') -> Except e a -> Except e' a
withExceptT :: forall (m :: Type -> Type) e e' a. Functor m => (e -> e') -> ExceptT e m a -> ExceptT e' m a
type Except e = ExceptT e Identity
newtype ExceptT e (m :: Type -> Type) a = ExceptT (m (Either e a))
throwE :: forall (m :: Type -> Type) e a. Monad m => e -> ExceptT e m a
except :: forall (m :: Type -> Type) e a. Monad m => Either e a -> ExceptT e m a
catchE :: forall (m :: Type -> Type) e a e'. Monad m => ExceptT e m a -> (e -> ExceptT e' m a) -> ExceptT e' m a
transExcept :: forall t m e a. (MonadTransTunnel t, Applicative (Tunnel t), Monad m) => t (ExceptT e m) a -> t m (Either e a)

Documentation

mapExcept :: (Either e a -> Either e' b) -> Except e a -> Except e' b #

Map the unwrapped computation using the given function.

runExcept (mapExcept f m) = f (runExcept m)

mapExceptT :: (m (Either e a) -> n (Either e' b)) -> ExceptT e m a -> ExceptT e' n b #

Map the unwrapped computation using the given function.

runExceptT (mapExceptT f m) = f (runExceptT m)

runExcept :: Except e a -> Either e a #

Extractor for computations in the exception monad. (The inverse of except).

runExceptT :: ExceptT e m a -> m (Either e a) #

The inverse of ExceptT.

withExcept :: (e -> e') -> Except e a -> Except e' a #

Transform any exceptions thrown by the computation using the given function (a specialization of withExceptT).

withExceptT :: forall (m :: Type -> Type) e e' a. Functor m => (e -> e') -> ExceptT e m a -> ExceptT e' m a #

Transform any exceptions thrown by the computation using the given function.

type Except e = ExceptT e Identity #

The parameterizable exception monad.

Computations are either exceptions or normal values.

The return function returns a normal value, while >>= exits on the first exception. For a variant that continues after an error and collects all the errors, see Errors.

newtype ExceptT e (m :: Type -> Type) a #

A monad transformer that adds exceptions to other monads.

ExceptT constructs a monad parameterized over two things:

e - The exception type.
m - The inner monad.

The return function yields a computation that produces the given value, while >>= sequences two subcomputations, exiting on the first exception.

Constructors

ExceptT (m (Either e a))

Instances

Instances details

TransConstraint MonadFail (ExceptT e) Source #
Instance details Defined in Control.Monad.Ology.Specific.ExceptT Methods hasTransConstraint :: forall (m :: Type -> Type). MonadFail m => Dict (MonadFail (ExceptT e m)) Source #
TransConstraint MonadFix (ExceptT e) Source #
Instance details Defined in Control.Monad.Ology.Specific.ExceptT Methods hasTransConstraint :: forall (m :: Type -> Type). MonadFix m => Dict (MonadFix (ExceptT e m)) Source #
TransConstraint MonadIO (ExceptT e) Source #
Instance details Defined in Control.Monad.Ology.Specific.ExceptT Methods hasTransConstraint :: forall (m :: Type -> Type). MonadIO m => Dict (MonadIO (ExceptT e m)) Source #
TransConstraint Functor (ExceptT e) Source #
Instance details Defined in Control.Monad.Ology.Specific.ExceptT Methods hasTransConstraint :: forall (m :: Type -> Type). Functor m => Dict (Functor (ExceptT e m)) Source #
TransConstraint Monad (ExceptT e) Source #
Instance details Defined in Control.Monad.Ology.Specific.ExceptT Methods hasTransConstraint :: forall (m :: Type -> Type). Monad m => Dict (Monad (ExceptT e m)) Source #
Monoid e => TransConstraint MonadPlus (ExceptT e) Source #
Instance details Defined in Control.Monad.Ology.Specific.ExceptT Methods hasTransConstraint :: forall (m :: Type -> Type). MonadPlus m => Dict (MonadPlus (ExceptT e m)) Source #
TransConstraint MonadException (ExceptT e) Source #
Instance details Defined in Control.Monad.Ology.Specific.ExceptT Methods hasTransConstraint :: forall (m :: Type -> Type). MonadException m => Dict (MonadException (ExceptT e m)) Source #
TransConstraint MonadInner (ExceptT e) Source #
Instance details Defined in Control.Monad.Ology.Specific.ExceptT Methods hasTransConstraint :: forall (m :: Type -> Type). MonadInner m => Dict (MonadInner (ExceptT e m)) Source #
MonadTransCoerce (ExceptT e) Source #
Instance details Defined in Control.Monad.Ology.Specific.ExceptT Methods transCoerce :: forall (m1 :: Type -> Type) (m2 :: Type -> Type). Coercible m1 m2 => Dict (Coercible (ExceptT e m1) (ExceptT e m2)) Source #
MonadTransHoist (ExceptT e) Source #
Instance details Defined in Control.Monad.Ology.Specific.ExceptT Methods hoist :: forall (m1 :: Type -> Type) (m2 :: Type -> Type). (Monad m1, Monad m2) => (m1 --> m2) -> ExceptT e m1 --> ExceptT e m2 Source #
MonadTransTunnel (ExceptT e) Source #
Instance details Defined in Control.Monad.Ology.Specific.ExceptT Associated Types type Tunnel (ExceptT e) :: Type -> Type Source # Methods tunnel :: Monad m => ((forall (m1 :: Type -> Type) a. Monad m1 => ExceptT e m1 a -> m1 (Tunnel (ExceptT e) a)) -> m (Tunnel (ExceptT e) r)) -> ExceptT e m r Source #
MonadTrans (ExceptT e)
Instance details Defined in Control.Monad.Trans.Except Methods lift :: Monad m => m a -> ExceptT e m a #
MonadFail m => MonadFail (ExceptT e m)
Instance details Defined in Control.Monad.Trans.Except Methods fail :: String -> ExceptT e m a #
MonadFix m => MonadFix (ExceptT e m)
Instance details Defined in Control.Monad.Trans.Except Methods mfix :: (a -> ExceptT e m a) -> ExceptT e m a #
MonadIO m => MonadIO (ExceptT e m)
Instance details Defined in Control.Monad.Trans.Except Methods liftIO :: IO a -> ExceptT e m a #
MonadZip m => MonadZip (ExceptT e m)
Instance details Defined in Control.Monad.Trans.Except Methods mzip :: ExceptT e m a -> ExceptT e m b -> ExceptT e m (a, b) # mzipWith :: (a -> b -> c) -> ExceptT e m a -> ExceptT e m b -> ExceptT e m c # munzip :: ExceptT e m (a, b) -> (ExceptT e m a, ExceptT e m b) #
Foldable f => Foldable (ExceptT e f)
Instance details Defined in Control.Monad.Trans.Except Methods fold :: Monoid m => ExceptT e f m -> m # foldMap :: Monoid m => (a -> m) -> ExceptT e f a -> m # foldMap' :: Monoid m => (a -> m) -> ExceptT e f a -> m # foldr :: (a -> b -> b) -> b -> ExceptT e f a -> b # foldr' :: (a -> b -> b) -> b -> ExceptT e f a -> b # foldl :: (b -> a -> b) -> b -> ExceptT e f a -> b # foldl' :: (b -> a -> b) -> b -> ExceptT e f a -> b # foldr1 :: (a -> a -> a) -> ExceptT e f a -> a # foldl1 :: (a -> a -> a) -> ExceptT e f a -> a # toList :: ExceptT e f a -> [a] # null :: ExceptT e f a -> Bool # length :: ExceptT e f a -> Int # elem :: Eq a => a -> ExceptT e f a -> Bool # maximum :: Ord a => ExceptT e f a -> a # minimum :: Ord a => ExceptT e f a -> a # sum :: Num a => ExceptT e f a -> a # product :: Num a => ExceptT e f a -> a #
(Eq e, Eq1 m) => Eq1 (ExceptT e m)
Instance details Defined in Control.Monad.Trans.Except Methods liftEq :: (a -> b -> Bool) -> ExceptT e m a -> ExceptT e m b -> Bool #
(Ord e, Ord1 m) => Ord1 (ExceptT e m)
Instance details Defined in Control.Monad.Trans.Except Methods liftCompare :: (a -> b -> Ordering) -> ExceptT e m a -> ExceptT e m b -> Ordering #
(Read e, Read1 m) => Read1 (ExceptT e m)
Instance details Defined in Control.Monad.Trans.Except Methods liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (ExceptT e m a) # liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [ExceptT e m a] # liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (ExceptT e m a) # liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [ExceptT e m a] #
(Show e, Show1 m) => Show1 (ExceptT e m)
Instance details Defined in Control.Monad.Trans.Except Methods liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> ExceptT e m a -> ShowS # liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [ExceptT e m a] -> ShowS #
Contravariant m => Contravariant (ExceptT e m)
Instance details Defined in Control.Monad.Trans.Except Methods contramap :: (a' -> a) -> ExceptT e m a -> ExceptT e m a' # (>$) :: b -> ExceptT e m b -> ExceptT e m a #
Traversable f => Traversable (ExceptT e f)
Instance details Defined in Control.Monad.Trans.Except Methods traverse :: Applicative f0 => (a -> f0 b) -> ExceptT e f a -> f0 (ExceptT e f b) # sequenceA :: Applicative f0 => ExceptT e f (f0 a) -> f0 (ExceptT e f a) # mapM :: Monad m => (a -> m b) -> ExceptT e f a -> m (ExceptT e f b) # sequence :: Monad m => ExceptT e f (m a) -> m (ExceptT e f a) #
(Functor m, Monad m, Monoid e) => Alternative (ExceptT e m)
Instance details Defined in Control.Monad.Trans.Except Methods empty :: ExceptT e m a # (<\|>) :: ExceptT e m a -> ExceptT e m a -> ExceptT e m a # some :: ExceptT e m a -> ExceptT e m [a] # many :: ExceptT e m a -> ExceptT e m [a] #
(Functor m, Monad m) => Applicative (ExceptT e m)
Instance details Defined in Control.Monad.Trans.Except Methods pure :: a -> ExceptT e m a # (<>) :: ExceptT e m (a -> b) -> ExceptT e m a -> ExceptT e m b # liftA2 :: (a -> b -> c) -> ExceptT e m a -> ExceptT e m b -> ExceptT e m c # (>) :: ExceptT e m a -> ExceptT e m b -> ExceptT e m b # (<*) :: ExceptT e m a -> ExceptT e m b -> ExceptT e m a #
Functor m => Functor (ExceptT e m)
Instance details Defined in Control.Monad.Trans.Except Methods fmap :: (a -> b) -> ExceptT e m a -> ExceptT e m b # (<$) :: a -> ExceptT e m b -> ExceptT e m a #
Monad m => Monad (ExceptT e m)
Instance details Defined in Control.Monad.Trans.Except Methods (>>=) :: ExceptT e m a -> (a -> ExceptT e m b) -> ExceptT e m b # (>>) :: ExceptT e m a -> ExceptT e m b -> ExceptT e m b # return :: a -> ExceptT e m a #
(Monad m, Monoid e) => MonadPlus (ExceptT e m)
Instance details Defined in Control.Monad.Trans.Except Methods mzero :: ExceptT e m a # mplus :: ExceptT e m a -> ExceptT e m a -> ExceptT e m a #
Invariant m => Invariant (ExceptT e m)	from the `transformers` package
Instance details Defined in Data.Functor.Invariant Methods invmap :: (a -> b) -> (b -> a) -> ExceptT e m a -> ExceptT e m b #
MonadException m => MonadException (ExceptT e m) Source #
Instance details Defined in Control.Monad.Ology.Specific.ExceptT Associated Types type Exc (ExceptT e m) Source # Methods throwExc :: Exc (ExceptT e m) -> ExceptT e m a Source # catchExc :: ExceptT e m a -> (Exc (ExceptT e m) -> ExceptT e m a) -> ExceptT e m a Source #
MonadInner m => MonadInner (ExceptT e m) Source #
Instance details Defined in Control.Monad.Ology.Specific.ExceptT Methods retrieveInner :: ExceptT e m a -> Result (Exc (ExceptT e m)) a Source #
MonadCatch ex m => MonadCatch (Either e ex) (ExceptT e m) Source #
Instance details Defined in Control.Monad.Ology.Specific.ExceptT Methods catch :: ExceptT e m a -> (Either e ex -> ExceptT e m a) -> ExceptT e m a Source #
MonadThrow ex m => MonadThrow (Either e ex) (ExceptT e m) Source #
Instance details Defined in Control.Monad.Ology.Specific.ExceptT Methods throw :: Either e ex -> ExceptT e m a Source #
(Read e, Read1 m, Read a) => Read (ExceptT e m a)
Instance details Defined in Control.Monad.Trans.Except Methods readsPrec :: Int -> ReadS (ExceptT e m a) # readList :: ReadS [ExceptT e m a] # readPrec :: ReadPrec (ExceptT e m a) # readListPrec :: ReadPrec [ExceptT e m a] #
(Show e, Show1 m, Show a) => Show (ExceptT e m a)
Instance details Defined in Control.Monad.Trans.Except Methods showsPrec :: Int -> ExceptT e m a -> ShowS # show :: ExceptT e m a -> String # showList :: [ExceptT e m a] -> ShowS #
(Eq e, Eq1 m, Eq a) => Eq (ExceptT e m a)
Instance details Defined in Control.Monad.Trans.Except Methods (==) :: ExceptT e m a -> ExceptT e m a -> Bool # (/=) :: ExceptT e m a -> ExceptT e m a -> Bool #
(Ord e, Ord1 m, Ord a) => Ord (ExceptT e m a)
Instance details Defined in Control.Monad.Trans.Except Methods compare :: ExceptT e m a -> ExceptT e m a -> Ordering # (<) :: ExceptT e m a -> ExceptT e m a -> Bool # (<=) :: ExceptT e m a -> ExceptT e m a -> Bool # (>) :: ExceptT e m a -> ExceptT e m a -> Bool # (>=) :: ExceptT e m a -> ExceptT e m a -> Bool # max :: ExceptT e m a -> ExceptT e m a -> ExceptT e m a # min :: ExceptT e m a -> ExceptT e m a -> ExceptT e m a #
type Tunnel (ExceptT e) Source #
Instance details Defined in Control.Monad.Ology.Specific.ExceptT type Tunnel (ExceptT e) = Either e
type Exc (ExceptT e m) Source #
Instance details Defined in Control.Monad.Ology.Specific.ExceptT type Exc (ExceptT e m) = Either e (Exc m)

throwE :: forall (m :: Type -> Type) e a. Monad m => e -> ExceptT e m a #

Signal an exception value e.

```
runExceptT (throwE e) = return (Left e)
```
```
throwE e >>= m = throwE e
```

except :: forall (m :: Type -> Type) e a. Monad m => Either e a -> ExceptT e m a #

Constructor for computations in the exception monad. (The inverse of runExcept).

catchE #

Arguments

:: forall (m :: Type -> Type) e a e'. Monad m
=> ExceptT e m a	the inner computation
-> (e -> ExceptT e' m a)	a handler for exceptions in the inner computation
-> ExceptT e' m a

Handle an exception.

```
catchE (lift m) h = lift m
```
```
catchE (throwE e) h = h e
```

transExcept :: forall t m e a. (MonadTransTunnel t, Applicative (Tunnel t), Monad m) => t (ExceptT e m) a -> t m (Either e a) Source #

Orphan instances

TransConstraint MonadFail (ExceptT e) Source #
Instance details Methods hasTransConstraint :: forall (m :: Type -> Type). MonadFail m => Dict (MonadFail (ExceptT e m)) Source #
TransConstraint MonadFix (ExceptT e) Source #
Instance details Methods hasTransConstraint :: forall (m :: Type -> Type). MonadFix m => Dict (MonadFix (ExceptT e m)) Source #
TransConstraint MonadIO (ExceptT e) Source #
Instance details Methods hasTransConstraint :: forall (m :: Type -> Type). MonadIO m => Dict (MonadIO (ExceptT e m)) Source #
TransConstraint Functor (ExceptT e) Source #
Instance details Methods hasTransConstraint :: forall (m :: Type -> Type). Functor m => Dict (Functor (ExceptT e m)) Source #
TransConstraint Monad (ExceptT e) Source #
Instance details Methods hasTransConstraint :: forall (m :: Type -> Type). Monad m => Dict (Monad (ExceptT e m)) Source #
Monoid e => TransConstraint MonadPlus (ExceptT e) Source #
Instance details Methods hasTransConstraint :: forall (m :: Type -> Type). MonadPlus m => Dict (MonadPlus (ExceptT e m)) Source #
TransConstraint MonadException (ExceptT e) Source #
Instance details Methods hasTransConstraint :: forall (m :: Type -> Type). MonadException m => Dict (MonadException (ExceptT e m)) Source #
TransConstraint MonadInner (ExceptT e) Source #
Instance details Methods hasTransConstraint :: forall (m :: Type -> Type). MonadInner m => Dict (MonadInner (ExceptT e m)) Source #
MonadTransCoerce (ExceptT e) Source #
Instance details Methods transCoerce :: forall (m1 :: Type -> Type) (m2 :: Type -> Type). Coercible m1 m2 => Dict (Coercible (ExceptT e m1) (ExceptT e m2)) Source #
MonadTransHoist (ExceptT e) Source #
Instance details Methods hoist :: forall (m1 :: Type -> Type) (m2 :: Type -> Type). (Monad m1, Monad m2) => (m1 --> m2) -> ExceptT e m1 --> ExceptT e m2 Source #
MonadTransTunnel (ExceptT e) Source #
Instance details Associated Types type Tunnel (ExceptT e) :: Type -> Type Source # Methods tunnel :: Monad m => ((forall (m1 :: Type -> Type) a. Monad m1 => ExceptT e m1 a -> m1 (Tunnel (ExceptT e) a)) -> m (Tunnel (ExceptT e) r)) -> ExceptT e m r Source #
MonadException m => MonadException (ExceptT e m) Source #
Instance details Associated Types type Exc (ExceptT e m) Source # Methods throwExc :: Exc (ExceptT e m) -> ExceptT e m a Source # catchExc :: ExceptT e m a -> (Exc (ExceptT e m) -> ExceptT e m a) -> ExceptT e m a Source #
MonadInner m => MonadInner (ExceptT e m) Source #
Instance details Methods retrieveInner :: ExceptT e m a -> Result (Exc (ExceptT e m)) a Source #
MonadCatch ex m => MonadCatch (Either e ex) (ExceptT e m) Source #
Instance details Methods catch :: ExceptT e m a -> (Either e ex -> ExceptT e m a) -> ExceptT e m a Source #
MonadThrow ex m => MonadThrow (Either e ex) (ExceptT e m) Source #
Instance details Methods throw :: Either e ex -> ExceptT e m a Source #