| Safe Haskell | Safe-Inferred |
|---|---|
| Language | Haskell2010 |
Control.Exception.Annotated.UnliftIO
Description
This module presents the same interface as
Control.Exception.Annotated, but uses MonadUnliftIO instead of
MonadCatch or MonadThrow.
Since: 0.1.2.0
Synopsis
- data AnnotatedException exception = AnnotatedException {
- annotations :: [Annotation]
- exception :: exception
- new :: e -> AnnotatedException e
- throwWithCallStack :: forall e m a. (MonadIO m, Exception e, HasCallStack) => e -> m a
- checkpoint :: forall m a. MonadUnliftIO m => Annotation -> m a -> m a
- checkpointMany :: forall m a. MonadUnliftIO m => [Annotation] -> m a -> m a
- checkpointCallStack :: (MonadCatch m, HasCallStack) => m a -> m a
- checkpointCallStackWith :: forall m a. (MonadUnliftIO m, HasCallStack) => [Annotation] -> m a -> m a
- catch :: forall e m a. (MonadUnliftIO m, Exception e) => m a -> (e -> m a) -> m a
- catches :: forall m a. MonadUnliftIO m => m a -> [Handler m a] -> m a
- tryAnnotated :: forall e m a. (MonadUnliftIO m, Exception e) => m a -> m (Either (AnnotatedException e) a)
- try :: forall e m a. (MonadUnliftIO m, Exception e) => m a -> m (Either e a)
- check :: Exception e => AnnotatedException SomeException -> Maybe (AnnotatedException e)
- hide :: Exception e => AnnotatedException e -> AnnotatedException SomeException
- annotatedExceptionCallStack :: AnnotatedException exception -> Maybe CallStack
- addCallStackToException :: CallStack -> AnnotatedException exception -> AnnotatedException exception
- data Annotation where
- Annotation :: AnnC a => a -> Annotation
- newtype CallStackAnnotation = CallStackAnnotation {
- unCallStackAnnotation :: [(String, SrcLoc)]
- class (Typeable e, Show e) => Exception e where
- toException :: e -> SomeException
- fromException :: SomeException -> Maybe e
- displayException :: e -> String
- data SomeException = Exception e => SomeException e
- throw :: forall e m a. (MonadIO m, Exception e) => e -> m a
- data Handler (m :: Type -> Type) a = Exception e => Handler (e -> m a)
- class Monad m => MonadIO (m :: Type -> Type) where
- class MonadIO m => MonadUnliftIO (m :: Type -> Type) where
- withRunInIO :: ((forall a. m a -> IO a) -> IO b) -> m b
The Main Type
data AnnotatedException exception Source #
The AnnotatedException type wraps an exception with
a [. This can provide a sort of a manual stack trace with
programmer provided data.Annotation]
Since: 0.1.0.0
Constructors
| AnnotatedException | |
Fields
| |
Instances
new :: e -> AnnotatedException e Source #
Attach an empty [ to an exception.Annotation]
Since: 0.1.0.0
throwWithCallStack :: forall e m a. (MonadIO m, Exception e, HasCallStack) => e -> m a Source #
Like throwWithCallStack, but uses MonadIO instead of
MonadThrow.
Since: 0.1.2.0
Annotating Exceptions
checkpoint :: forall m a. MonadUnliftIO m => Annotation -> m a -> m a Source #
Like checkpoint, but uses MonadUnliftIO instead of MonadCatch.
Since: 0.1.2.0
checkpointMany :: forall m a. MonadUnliftIO m => [Annotation] -> m a -> m a Source #
Like checkpointMany, but uses MonadUnliftIO instead of
MonadCatch.
Since: 0.1.2.0
checkpointCallStack :: (MonadCatch m, HasCallStack) => m a -> m a Source #
checkpointCallStackWith :: forall m a. (MonadUnliftIO m, HasCallStack) => [Annotation] -> m a -> m a Source #
Like checkpointCallStackWith, but uses MonadUnliftIO instead of
MonadCatch.
Since: 0.1.2.0
Handling Exceptions
catch :: forall e m a. (MonadUnliftIO m, Exception e) => m a -> (e -> m a) -> m a Source #
Like catch, but uses MonadUnliftIO instead of MonadCatch.
Since: 0.1.2.0
catches :: forall m a. MonadUnliftIO m => m a -> [Handler m a] -> m a Source #
Like catches, bt uses MonadUnliftIO instead of MonadCatch.
Since: 0.1.2.0
tryAnnotated :: forall e m a. (MonadUnliftIO m, Exception e) => m a -> m (Either (AnnotatedException e) a) Source #
Like tryAnnotated but uses MonadUnliftIO instead of MonadCatch.
Since: 0.1.2.0
try :: forall e m a. (MonadUnliftIO m, Exception e) => m a -> m (Either e a) Source #
Like try but uses MonadUnliftIO instead of MonadCatch.
Since: 0.1.2.0
Manipulating Annotated Exceptions
check :: Exception e => AnnotatedException SomeException -> Maybe (AnnotatedException e) Source #
Call fromException on the underlying Exception, attaching the
annotations to the result.
Since: 0.1.0.0
hide :: Exception e => AnnotatedException e -> AnnotatedException SomeException Source #
Call toException on the underlying Exception.
Since: 0.1.0.0
annotatedExceptionCallStack :: AnnotatedException exception -> Maybe CallStack Source #
Retrieves the CallStack from an AnnotatedException if one is present.
Since: 0.1.0.0
addCallStackToException :: CallStack -> AnnotatedException exception -> AnnotatedException exception Source #
Adds a CallStack to the given AnnotatedException. This function will
search through the existing annotations, and it will not add a second
CallStack to the list.
Since: 0.1.0.0
Re-exports from Data.Annotation
data Annotation where Source #
An Annotation is a wrapper around a value that includes a Typeable
constraint so we can later unpack it. It is essentially a 'Dynamic, but
we also include Show and Eq so it's more useful.
Since: 0.1.0.0
Constructors
| Annotation :: AnnC a => a -> Annotation |
Instances
| Eq Annotation Source # | Since: 0.1.0.0 |
Defined in Data.Annotation | |
| Show Annotation Source # | Since: 0.1.0.0 |
Defined in Data.Annotation Methods showsPrec :: Int -> Annotation -> ShowS # show :: Annotation -> String # showList :: [Annotation] -> ShowS # | |
| IsString Annotation Source # | Since: 0.1.0.0 |
Defined in Data.Annotation Methods fromString :: String -> Annotation # | |
newtype CallStackAnnotation Source #
A wrapper type for putting a CallStack into an Annotation. We need
this because CallStack does not have an Eq instance.
Since: 0.1.0.0
Constructors
| CallStackAnnotation | |
Fields
| |
Instances
| Eq CallStackAnnotation Source # | |
Defined in Data.Annotation Methods (==) :: CallStackAnnotation -> CallStackAnnotation -> Bool # (/=) :: CallStackAnnotation -> CallStackAnnotation -> Bool # | |
| Show CallStackAnnotation Source # | |
Defined in Data.Annotation Methods showsPrec :: Int -> CallStackAnnotation -> ShowS # show :: CallStackAnnotation -> String # showList :: [CallStackAnnotation] -> ShowS # | |
Re-exports from Control.Exception.Safe
class (Typeable e, Show e) => Exception e where #
Any type that you wish to throw or catch as an exception must be an
instance of the Exception class. The simplest case is a new exception
type directly below the root:
data MyException = ThisException | ThatException
deriving Show
instance Exception MyExceptionThe default method definitions in the Exception class do what we need
in this case. You can now throw and catch ThisException and
ThatException as exceptions:
*Main> throw ThisException `catch` \e -> putStrLn ("Caught " ++ show (e :: MyException))
Caught ThisException
In more complicated examples, you may wish to define a whole hierarchy of exceptions:
---------------------------------------------------------------------
-- Make the root exception type for all the exceptions in a compiler
data SomeCompilerException = forall e . Exception e => SomeCompilerException e
instance Show SomeCompilerException where
show (SomeCompilerException e) = show e
instance Exception SomeCompilerException
compilerExceptionToException :: Exception e => e -> SomeException
compilerExceptionToException = toException . SomeCompilerException
compilerExceptionFromException :: Exception e => SomeException -> Maybe e
compilerExceptionFromException x = do
SomeCompilerException a <- fromException x
cast a
---------------------------------------------------------------------
-- Make a subhierarchy for exceptions in the frontend of the compiler
data SomeFrontendException = forall e . Exception e => SomeFrontendException e
instance Show SomeFrontendException where
show (SomeFrontendException e) = show e
instance Exception SomeFrontendException where
toException = compilerExceptionToException
fromException = compilerExceptionFromException
frontendExceptionToException :: Exception e => e -> SomeException
frontendExceptionToException = toException . SomeFrontendException
frontendExceptionFromException :: Exception e => SomeException -> Maybe e
frontendExceptionFromException x = do
SomeFrontendException a <- fromException x
cast a
---------------------------------------------------------------------
-- Make an exception type for a particular frontend compiler exception
data MismatchedParentheses = MismatchedParentheses
deriving Show
instance Exception MismatchedParentheses where
toException = frontendExceptionToException
fromException = frontendExceptionFromExceptionWe can now catch a MismatchedParentheses exception as
MismatchedParentheses, SomeFrontendException or
SomeCompilerException, but not other types, e.g. IOException:
*Main> throw MismatchedParentheses `catch` \e -> putStrLn ("Caught " ++ show (e :: MismatchedParentheses))
Caught MismatchedParentheses
*Main> throw MismatchedParentheses `catch` \e -> putStrLn ("Caught " ++ show (e :: SomeFrontendException))
Caught MismatchedParentheses
*Main> throw MismatchedParentheses `catch` \e -> putStrLn ("Caught " ++ show (e :: SomeCompilerException))
Caught MismatchedParentheses
*Main> throw MismatchedParentheses `catch` \e -> putStrLn ("Caught " ++ show (e :: IOException))
*** Exception: MismatchedParentheses
Minimal complete definition
Nothing
Methods
toException :: e -> SomeException #
fromException :: SomeException -> Maybe e #
displayException :: e -> String #
Render this exception value in a human-friendly manner.
Default implementation: show
Since: base-4.8.0.0
Instances
data SomeException #
The SomeException type is the root of the exception type hierarchy.
When an exception of type e is thrown, behind the scenes it is
encapsulated in a SomeException.
Constructors
| Exception e => SomeException e |
Instances
| Show SomeException | Since: base-3.0 |
Defined in GHC.Exception.Type Methods showsPrec :: Int -> SomeException -> ShowS # show :: SomeException -> String # showList :: [SomeException] -> ShowS # | |
| Exception SomeException | Since: base-3.0 |
Defined in GHC.Exception.Type Methods toException :: SomeException -> SomeException # fromException :: SomeException -> Maybe SomeException # displayException :: SomeException -> String # | |
class Monad m => MonadIO (m :: Type -> Type) where #
Monads in which IO computations may be embedded.
Any monad built by applying a sequence of monad transformers to the
IO monad will be an instance of this class.
Instances should satisfy the following laws, which state that liftIO
is a transformer of monads:
Instances
| MonadIO IO | Since: base-4.9.0.0 |
Defined in Control.Monad.IO.Class | |
| MonadIO Q | |
Defined in Language.Haskell.TH.Syntax | |
| MonadIO m => MonadIO (IdentityT m) | |
Defined in Control.Monad.Trans.Identity | |
| (Error e, MonadIO m) => MonadIO (ErrorT e m) | |
Defined in Control.Monad.Trans.Error | |
| MonadIO m => MonadIO (ReaderT r m) | |
Defined in Control.Monad.Trans.Reader | |
class MonadIO m => MonadUnliftIO (m :: Type -> Type) where #
Monads which allow their actions to be run in IO.
While MonadIO allows an IO action to be lifted into another
monad, this class captures the opposite concept: allowing you to
capture the monadic context. Note that, in order to meet the laws
given below, the intuition is that a monad must have no monadic
state, but may have monadic context. This essentially limits
MonadUnliftIO to ReaderT and IdentityT transformers on top of
IO.
Laws. For any value u returned by askUnliftIO, it must meet the
monad transformer laws as reformulated for MonadUnliftIO:
unliftIO u . return = return
unliftIO u (m >>= f) = unliftIO u m >>= unliftIO u . f
Instances of MonadUnliftIO must also satisfy the idempotency law:
askUnliftIO >>= \u -> (liftIO . unliftIO u) m = m
This law showcases two properties. First, askUnliftIO doesn't change
the monadic context, and second, liftIO . unliftIO u is equivalent to
id IF called in the same monadic context as askUnliftIO.
Since: unliftio-core-0.1.0.0
Methods
withRunInIO :: ((forall a. m a -> IO a) -> IO b) -> m b #
Convenience function for capturing the monadic context and running an IO
action with a runner function. The runner function is used to run a monadic
action m in IO.
Since: unliftio-core-0.1.0.0
Instances
| MonadUnliftIO IO | |
Defined in Control.Monad.IO.Unlift | |
| MonadUnliftIO m => MonadUnliftIO (IdentityT m) | |
Defined in Control.Monad.IO.Unlift | |
| MonadUnliftIO m => MonadUnliftIO (ReaderT r m) | |
Defined in Control.Monad.IO.Unlift | |