Safe Haskell	Safe
Language	Haskell98

UnexceptionalIO.Trans

Contents

Unsafe entry points
Pseudo exceptions
Pseudo exception helpers
Orphan instances

Description

When you've caught all the exceptions that can be handled safely, this is what you're left with.

runExceptIO . fromIO ≡ id

It is intended that you use qualified imports with this library.

import UnexceptionalIO.Trans (UIO)
import qualified UnexceptionalIO.Trans as UIO

Synopsis

data UIO a
class Monad m => Unexceptional (m :: Type -> Type) where
- lift :: UIO a -> m a
fromIO :: Unexceptional m => IO a -> ExceptT SomeNonPseudoException m a
fromIO' :: (Exception e, Unexceptional m) => (SomeNonPseudoException -> e) -> IO a -> ExceptT e m a
run :: MonadIO m => UIO a -> m a
runExceptIO :: (Exception e, MonadIO m) => ExceptT e UIO a -> m a
unsafeFromIO :: Unexceptional m => IO a -> m a
data SomeNonPseudoException
data PseudoException
data ProgrammerError
data ExternalError
bracket :: Unexceptional m => UIO a -> (a -> UIO ()) -> (a -> UIO c) -> m c
forkFinally :: Unexceptional m => UIO a -> (Either PseudoException a -> UIO ()) -> m ThreadId
fork :: Unexceptional m => UIO () -> m ThreadId
newtype ChildThreadError = ChildThreadError PseudoException

Documentation

data UIO a #

Like IO, but throws only PseudoException

Instances

Monad UIO
Instance details Defined in UnexceptionalIO Methods (>>=) :: UIO a -> (a -> UIO b) -> UIO b # (>>) :: UIO a -> UIO b -> UIO b # return :: a -> UIO a # fail :: String -> UIO a #
Functor UIO
Instance details Defined in UnexceptionalIO Methods fmap :: (a -> b) -> UIO a -> UIO b # (<$) :: a -> UIO b -> UIO a #
MonadFix UIO
Instance details Defined in UnexceptionalIO Methods mfix :: (a -> UIO a) -> UIO a #
Applicative UIO
Instance details Defined in UnexceptionalIO Methods pure :: a -> UIO a # (<>) :: UIO (a -> b) -> UIO a -> UIO b # liftA2 :: (a -> b -> c) -> UIO a -> UIO b -> UIO c # (>) :: UIO a -> UIO b -> UIO b # (<*) :: UIO a -> UIO b -> UIO a #
Unexceptional UIO
Instance details Defined in UnexceptionalIO Methods lift :: UIO a -> UIO a #

class Monad m => Unexceptional (m :: Type -> Type) where #

Monads in which UIO computations may be embedded

Methods

lift :: UIO a -> m a #

Instances

Unexceptional IO
Instance details Defined in UnexceptionalIO Methods lift :: UIO a -> IO a #
Unexceptional UIO
Instance details Defined in UnexceptionalIO Methods lift :: UIO a -> UIO a #
Unexceptional m => Unexceptional (MaybeT m) Source #
Instance details Defined in UnexceptionalIO.Trans Methods lift :: UIO a -> MaybeT m a #
Unexceptional m => Unexceptional (ListT m) Source #
Instance details Defined in UnexceptionalIO.Trans Methods lift :: UIO a -> ListT m a #
(Unexceptional m, Monoid w) => Unexceptional (WriterT w m) Source #
Instance details Defined in UnexceptionalIO.Trans Methods lift :: UIO a -> WriterT w m a #
(Unexceptional m, Monoid w) => Unexceptional (AccumT w m) Source #
Instance details Defined in UnexceptionalIO.Trans Methods lift :: UIO a -> AccumT w m a #
(Unexceptional m, Monoid w) => Unexceptional (WriterT w m) Source #
Instance details Defined in UnexceptionalIO.Trans Methods lift :: UIO a -> WriterT w m a #
Unexceptional m => Unexceptional (StateT s m) Source #
Instance details Defined in UnexceptionalIO.Trans Methods lift :: UIO a -> StateT s m a #
Unexceptional m => Unexceptional (StateT s m) Source #
Instance details Defined in UnexceptionalIO.Trans Methods lift :: UIO a -> StateT s m a #
Unexceptional m => Unexceptional (SelectT r m) Source #
Instance details Defined in UnexceptionalIO.Trans Methods lift :: UIO a -> SelectT r m a #
Unexceptional m => Unexceptional (IdentityT m) Source #
Instance details Defined in UnexceptionalIO.Trans Methods lift :: UIO a -> IdentityT m a #
Unexceptional m => Unexceptional (ExceptT e m) Source #
Instance details Defined in UnexceptionalIO.Trans Methods lift :: UIO a -> ExceptT e m a #
(Unexceptional m, Error e) => Unexceptional (ErrorT e m) Source #
Instance details Defined in UnexceptionalIO.Trans Methods lift :: UIO a -> ErrorT e m a #
Unexceptional m => Unexceptional (ReaderT r m) Source #
Instance details Defined in UnexceptionalIO.Trans Methods lift :: UIO a -> ReaderT r m a #
Unexceptional m => Unexceptional (ContT r m) Source #
Instance details Defined in UnexceptionalIO.Trans Methods lift :: UIO a -> ContT r m a #
(Unexceptional m, Monoid w) => Unexceptional (RWST r w s m) Source #
Instance details Defined in UnexceptionalIO.Trans Methods lift :: UIO a -> RWST r w s m a #
(Unexceptional m, Monoid w) => Unexceptional (RWST r w s m) Source #
Instance details Defined in UnexceptionalIO.Trans Methods lift :: UIO a -> RWST r w s m a #

fromIO :: Unexceptional m => IO a -> ExceptT SomeNonPseudoException m a Source #

Catch any exception but PseudoException in an IO action

fromIO' Source #

Arguments

:: (Exception e, Unexceptional m)
=> (SomeNonPseudoException -> e)	Default if an unexpected exception occurs
-> IO a
-> ExceptT e m a

Catch any e in an IO action, with a default mapping for unexpected cases

run :: MonadIO m => UIO a -> m a Source #

Re-embed UIO into MonadIO

runExceptIO :: (Exception e, MonadIO m) => ExceptT e UIO a -> m a Source #

Re-embed UIO and possible exception back into IO

Unsafe entry points

unsafeFromIO :: Unexceptional m => IO a -> m a #

You promise there are no exceptions but PseudoException thrown by this IO action

Pseudo exceptions

data SomeNonPseudoException #

Every SomeException but PseudoException

Instances

Show SomeNonPseudoException
Instance details Defined in UnexceptionalIO Methods showsPrec :: Int -> SomeNonPseudoException -> ShowS # show :: SomeNonPseudoException -> String # showList :: [SomeNonPseudoException] -> ShowS #
Exception SomeNonPseudoException
Instance details Defined in UnexceptionalIO Methods toException :: SomeNonPseudoException -> SomeException # fromException :: SomeException -> Maybe SomeNonPseudoException # displayException :: SomeNonPseudoException -> String #

data PseudoException #

Not everything handled by the exception system is a run-time error you can handle. This is the class of unrecoverable pseudo-exceptions.

Additionally, except for ExitCode any of these pseudo-exceptions you could never guarantee to have caught. Since they can come from anywhere at any time, we could never guarentee that UIO does not contain them.

Constructors

ProgrammerError ProgrammerError	Mistakes programmers make
ExternalError ExternalError	Errors thrown by the runtime
Exit ExitCode	Process exit requests

Instances

Show PseudoException
Instance details Defined in UnexceptionalIO Methods showsPrec :: Int -> PseudoException -> ShowS # show :: PseudoException -> String # showList :: [PseudoException] -> ShowS #
Exception PseudoException
Instance details Defined in UnexceptionalIO Methods toException :: PseudoException -> SomeException # fromException :: SomeException -> Maybe PseudoException # displayException :: PseudoException -> String #

data ProgrammerError #

Pseudo-exceptions caused by a programming error

Partial functions, error, undefined, etc

Instances

Show ProgrammerError
Instance details Defined in UnexceptionalIO Methods showsPrec :: Int -> ProgrammerError -> ShowS # show :: ProgrammerError -> String # showList :: [ProgrammerError] -> ShowS #
Exception ProgrammerError
Instance details Defined in UnexceptionalIO Methods toException :: ProgrammerError -> SomeException # fromException :: SomeException -> Maybe ProgrammerError # displayException :: ProgrammerError -> String #

data ExternalError #

Pseudo-exceptions thrown by the runtime environment

Constructors

CompactionFailed CompactionFailed
FixIOException FixIOException
AsyncException SomeAsyncException
BlockedIndefinitelyOnSTM BlockedIndefinitelyOnSTM
BlockedIndefinitelyOnMVar BlockedIndefinitelyOnMVar
Deadlock Deadlock
NonTermination NonTermination

Instances

Show ExternalError
Instance details Defined in UnexceptionalIO Methods showsPrec :: Int -> ExternalError -> ShowS # show :: ExternalError -> String # showList :: [ExternalError] -> ShowS #
Exception ExternalError
Instance details Defined in UnexceptionalIO Methods toException :: ExternalError -> SomeException # fromException :: SomeException -> Maybe ExternalError # displayException :: ExternalError -> String #

Pseudo exception helpers

bracket :: Unexceptional m => UIO a -> (a -> UIO ()) -> (a -> UIO c) -> m c #

When you're doing resource handling, PseudoException matters. You still need to use the bracket pattern to handle cleanup.

forkFinally :: Unexceptional m => UIO a -> (Either PseudoException a -> UIO ()) -> m ThreadId #

Mirrors forkFinally, but since the body is UIO, the thread must terminate successfully or because of PseudoException

fork :: Unexceptional m => UIO () -> m ThreadId #

Mirrors forkIO, but re-throws errors to the parent thread

Ignores manual thread kills, since those are on purpose.
Re-throws async exceptions (SomeAsyncException) as is.
Re-throws ExitCode as is in an attempt to exit with the requested code.
Wraps synchronous PseudoException in async ChildThreadError.

newtype ChildThreadError #

Async signal that a child thread ended due to non-async PseudoException

Constructors

ChildThreadError PseudoException

Instances

Show ChildThreadError
Instance details Defined in UnexceptionalIO Methods showsPrec :: Int -> ChildThreadError -> ShowS # show :: ChildThreadError -> String # showList :: [ChildThreadError] -> ShowS #
Exception ChildThreadError
Instance details Defined in UnexceptionalIO Methods toException :: ChildThreadError -> SomeException # fromException :: SomeException -> Maybe ChildThreadError # displayException :: ChildThreadError -> String #

Orphan instances

Unexceptional m => Unexceptional (MaybeT m) Source #
Instance details Methods lift :: UIO a -> MaybeT m a #
Unexceptional m => Unexceptional (ListT m) Source #
Instance details Methods lift :: UIO a -> ListT m a #
(Unexceptional m, Monoid w) => Unexceptional (WriterT w m) Source #
Instance details Methods lift :: UIO a -> WriterT w m a #
(Unexceptional m, Monoid w) => Unexceptional (AccumT w m) Source #
Instance details Methods lift :: UIO a -> AccumT w m a #
(Unexceptional m, Monoid w) => Unexceptional (WriterT w m) Source #
Instance details Methods lift :: UIO a -> WriterT w m a #
Unexceptional m => Unexceptional (StateT s m) Source #
Instance details Methods lift :: UIO a -> StateT s m a #
Unexceptional m => Unexceptional (StateT s m) Source #
Instance details Methods lift :: UIO a -> StateT s m a #
Unexceptional m => Unexceptional (SelectT r m) Source #
Instance details Methods lift :: UIO a -> SelectT r m a #
Unexceptional m => Unexceptional (IdentityT m) Source #
Instance details Methods lift :: UIO a -> IdentityT m a #
Unexceptional m => Unexceptional (ExceptT e m) Source #
Instance details Methods lift :: UIO a -> ExceptT e m a #
(Unexceptional m, Error e) => Unexceptional (ErrorT e m) Source #
Instance details Methods lift :: UIO a -> ErrorT e m a #
Unexceptional m => Unexceptional (ReaderT r m) Source #
Instance details Methods lift :: UIO a -> ReaderT r m a #
Unexceptional m => Unexceptional (ContT r m) Source #
Instance details Methods lift :: UIO a -> ContT r m a #
(Unexceptional m, Monoid w) => Unexceptional (RWST r w s m) Source #
Instance details Methods lift :: UIO a -> RWST r w s m a #
(Unexceptional m, Monoid w) => Unexceptional (RWST r w s m) Source #
Instance details Methods lift :: UIO a -> RWST r w s m a #

TypeError TypeError
ArithException ArithException
ArrayException ArrayException
AssertionFailed AssertionFailed
ErrorCall ErrorCall
NestedAtomically NestedAtomically
NoMethodError NoMethodError
PatternMatchFail PatternMatchFail
RecConError RecConError
RecSelError RecSelError
RecUpdError RecSelError