freckle-exception-0.0.0.0: Some extensions to the annotated-exception library
Safe HaskellNone
LanguageGHC2021

Freckle.App.Exception.Types

Synopsis

Documentation

data ExceptionHandler (m :: k -> Type) (a :: k) Source #

Constructors

Exception e => ExceptionHandler (e -> m a) 

data AnnotatedException exception #

The AnnotatedException type wraps an exception with a [Annotation]. This can provide a sort of a manual stack trace with programmer provided data.

Since: annotated-exception-0.1.0.0

Constructors

AnnotatedException 

Fields

Instances

Instances details
Foldable AnnotatedException 
Instance details

Defined in Control.Exception.Annotated

Methods

fold :: Monoid m => AnnotatedException m -> m #

foldMap :: Monoid m => (a -> m) -> AnnotatedException a -> m #

foldMap' :: Monoid m => (a -> m) -> AnnotatedException a -> m #

foldr :: (a -> b -> b) -> b -> AnnotatedException a -> b #

foldr' :: (a -> b -> b) -> b -> AnnotatedException a -> b #

foldl :: (b -> a -> b) -> b -> AnnotatedException a -> b #

foldl' :: (b -> a -> b) -> b -> AnnotatedException a -> b #

foldr1 :: (a -> a -> a) -> AnnotatedException a -> a #

foldl1 :: (a -> a -> a) -> AnnotatedException a -> a #

toList :: AnnotatedException a -> [a] #

null :: AnnotatedException a -> Bool #

length :: AnnotatedException a -> Int #

elem :: Eq a => a -> AnnotatedException a -> Bool #

maximum :: Ord a => AnnotatedException a -> a #

minimum :: Ord a => AnnotatedException a -> a #

sum :: Num a => AnnotatedException a -> a #

product :: Num a => AnnotatedException a -> a #

Traversable AnnotatedException 
Instance details

Defined in Control.Exception.Annotated

Applicative AnnotatedException 
Instance details

Defined in Control.Exception.Annotated

Functor AnnotatedException 
Instance details

Defined in Control.Exception.Annotated

Exception exception => Exception (AnnotatedException exception)

This instance of Exception is a bit interesting. It tries to do as much hiding and packing and flattening as possible to ensure that even exception handling machinery outside of this package can still intelligently handle it.

Any Exception can be caught as a AnnotatedException with an empty context, so catching a AnnotatedException e will also catch a regular e and give it an empty set of annotations.

For the most up to date details, see the test suite.

Since: annotated-exception-0.1.0.0

Instance details

Defined in Control.Exception.Annotated

Exception exception => Show (AnnotatedException exception) 
Instance details

Defined in Control.Exception.Annotated

Methods

showsPrec :: Int -> AnnotatedException exception -> ShowS #

show :: AnnotatedException exception -> String #

showList :: [AnnotatedException exception] -> ShowS #

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 MyException

The 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 = frontendExceptionFromException

We 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

Instances details
Exception AesonException 
Instance details

Defined in Data.Aeson.Types.Internal

Exception NestedAtomically

Since: base-4.0

Instance details

Defined in Control.Exception.Base

Exception NoMatchingContinuationPrompt

Since: base-4.18

Instance details

Defined in Control.Exception.Base

Exception NoMethodError

Since: base-4.0

Instance details

Defined in Control.Exception.Base

Exception NonTermination

Since: base-4.0

Instance details

Defined in Control.Exception.Base

Exception PatternMatchFail

Since: base-4.0

Instance details

Defined in Control.Exception.Base

Exception RecConError

Since: base-4.0

Instance details

Defined in Control.Exception.Base

Exception RecSelError

Since: base-4.0

Instance details

Defined in Control.Exception.Base

Exception RecUpdError

Since: base-4.0

Instance details

Defined in Control.Exception.Base

Exception TypeError

Since: base-4.9.0.0

Instance details

Defined in Control.Exception.Base

Exception Dynamic

Since: base-4.0.0.0

Instance details

Defined in Data.Dynamic

Exception Void

Since: base-4.8.0.0

Instance details

Defined in GHC.Exception.Type

Exception ErrorCall

Since: base-4.0.0.0

Instance details

Defined in GHC.Exception

Exception ArithException

Since: base-4.0.0.0

Instance details

Defined in GHC.Exception.Type

Exception SomeException

Since: base-3.0

Instance details

Defined in GHC.Exception.Type

Exception AllocationLimitExceeded

Since: base-4.8.0.0

Instance details

Defined in GHC.IO.Exception

Exception ArrayException

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Exception AssertionFailed

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Exception AsyncException

Since: base-4.7.0.0

Instance details

Defined in GHC.IO.Exception

Exception BlockedIndefinitelyOnMVar

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Exception BlockedIndefinitelyOnSTM

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Exception CompactionFailed

Since: base-4.10.0.0

Instance details

Defined in GHC.IO.Exception

Exception Deadlock

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Exception ExitCode

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Exception FixIOException

Since: base-4.11.0.0

Instance details

Defined in GHC.IO.Exception

Exception IOException

Since: base-4.1.0.0

Instance details

Defined in GHC.IO.Exception

Exception SomeAsyncException

Since: base-4.7.0.0

Instance details

Defined in GHC.IO.Exception

Exception IOPortException 
Instance details

Defined in GHC.IOPort

Methods

toException :: IOPortException -> SomeException #

fromException :: SomeException -> Maybe IOPortException #

displayException :: IOPortException -> String #

Exception Timeout

Since: base-4.7.0.0

Instance details

Defined in System.Timeout

Exception NotFoundException 
Instance details

Defined in Context.Internal

Exception InvalidAccess 
Instance details

Defined in Control.Monad.Trans.Resource.Internal

Exception ResourceCleanupException 
Instance details

Defined in Control.Monad.Trans.Resource.Internal

Exception StringException

Since: unliftio-0.1.0.0

Instance details

Defined in UnliftIO.Exception

Exception ConcException 
Instance details

Defined in UnliftIO.Internals.Async

Exception exception => Exception (AnnotatedException exception)

This instance of Exception is a bit interesting. It tries to do as much hiding and packing and flattening as possible to ensure that even exception handling machinery outside of this package can still intelligently handle it.

Any Exception can be caught as a AnnotatedException with an empty context, so catching a AnnotatedException e will also catch a regular e and give it an empty set of annotations.

For the most up to date details, see the test suite.

Since: annotated-exception-0.1.0.0

Instance details

Defined in Control.Exception.Annotated

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

Instances details
Exception SomeException

Since: base-3.0

Instance details

Defined in GHC.Exception.Type

Show SomeException

Since: base-3.0

Instance details

Defined in GHC.Exception.Type

type HasCallStack = ?callStack :: CallStack #

Request a CallStack.

NOTE: The implicit parameter ?callStack :: CallStack is an implementation detail and should not be considered part of the CallStack API, we may decide to change the implementation in the future.

Since: base-4.9.0.0