Control.Monad.Invert

Typeclass

class MonadIO m => MonadInvertIO m where

Associated Types

data InvertedIO m :: * -> *

type InvertedArg m

Methods

invertIO :: m a -> InvertedArg m -> IO (InvertedIO m a)

revertIO :: (InvertedArg m -> IO (InvertedIO m a)) -> m a

Instances

MonadInvertIO IO

MonadInvertIO m => MonadInvertIO (IdentityT m)

(Monoid w, MonadInvertIO m) => MonadInvertIO (WriterT w m)

MonadInvertIO m => MonadInvertIO (StateT s m)

MonadInvertIO m => MonadInvertIO (ReaderT r m)

(Error e, MonadInvertIO m) => MonadInvertIO (ErrorT e m)

MonadInvertIO m => MonadInvertIO (MEitherT e m)

Exceptions

finally :: MonadInvertIO m => m a -> m b -> m a

catch :: (Exception e, MonadInvertIO m) => m a -> (e -> m a) -> m a

block :: MonadInvertIO m => m a -> m a

unblock :: MonadInvertIO m => m a -> m a

bracket :: MonadInvertIO m => m a -> (a -> m b) -> (a -> m c) -> m c

There is a very important distinction between this function and bracket_: in this version, the monadic side effects from the initialization function and kept, while in bracket_ they are discarded.

bracket_ :: MonadInvertIO m => m a -> m b -> m c -> m c

See bracket.

onException :: MonadInvertIO m => m a -> m b -> m a

Memory allocation

alloca :: (Storable a, MonadInvertIO m) => (Ptr a -> m b) -> m b

allocaBytes :: MonadInvertIO m => Int -> (Ptr a -> m b) -> m b

withForeignPtr :: MonadInvertIO m => ForeignPtr a -> (Ptr a -> m b) -> m b