Moduleerrors-2.3.0Haskell98

Control.Error.Safe

This module extends the safe library's functions with corresponding versions compatible with Either and ExceptT, and also provides a few Maybe-compatible functions missing from safe.

I suffix the Either-compatible functions with Err and prefix the ExceptT-compatible functions with try.

Note that this library re-exports the Maybe compatible functions from safe in the Control.Error module, so they are not provided here.

The 'Z'-suffixed functions generalize the Maybe functions to also work with anything that implements MonadPlus, including:

Lists
Most parsers
ExceptT (if the left value is a Monoid)

43 values

Packageerrors-2.3.0
Exports43
LanguageHaskell98
LicenceBSD-3-Clause
SourceSafe.hs

Maybe-compatible functions

2 declarations

valueassertMay :: Bool -> Maybe ()

An assertion that fails in the Maybe monad

valuerightMay :: Either e a -> Maybe a

A fromRight that fails in the Maybe monad

Either-compatible functions

13 declarations

valuetailErr :: e -> [a] -> Either e [a]

A tail that fails in the Either monad

valueinitErr :: e -> [a] -> Either e [a]

An init that fails in the Either monad

valueheadErr :: e -> [a] -> Either e a

A head that fails in the Either monad

valuelastErr :: e -> [a] -> Either e a

A last that fails in the Either monad

valueminimumErr :: Ord a => e -> [a] -> Either e a

A minimum that fails in the Either monad

valuemaximumErr :: Ord a => e -> [a] -> Either e a

A maximum that fails in the Either monad

valuefoldr1Err :: e -> (a -> a -> a) -> [a] -> Either e a

A foldr1 that fails in the Either monad

valuefoldl1Err :: e -> (a -> a -> a) -> [a] -> Either e a

A foldl1 that fails in the Either monad

valuefoldl1Err' :: e -> (a -> a -> a) -> [a] -> Either e a

A foldl1' that fails in the Either monad

valueatErr :: e -> [a] -> Int -> Either e a

A (!!) that fails in the Either monad

valuereadErr :: Read a => e -> String -> Either e a

A read that fails in the Either monad

valueassertErr :: e -> Bool -> Either e ()

An assertion that fails in the Either monad

valuejustErr :: e -> Maybe a -> Either e a

A fromJust that fails in the Either monad

ExceptT-compatible functions

14 declarations

valuetryTail :: Monad m => e -> [a] -> ExceptT e m [a]

A tail that fails in the ExceptT monad

valuetryInit :: Monad m => e -> [a] -> ExceptT e m [a]

An init that fails in the ExceptT monad

valuetryHead :: Monad m => e -> [a] -> ExceptT e m a

A head that fails in the ExceptT monad

valuetryLast :: Monad m => e -> [a] -> ExceptT e m a

A last that fails in the ExceptT monad

valuetryMinimum :: (Monad m, Ord a) => e -> [a] -> ExceptT e m a

A minimum that fails in the ExceptT monad

valuetryMaximum :: (Monad m, Ord a) => e -> [a] -> ExceptT e m a

A maximum that fails in the ExceptT monad

valuetryFoldr1 :: Monad m => e -> (a -> a -> a) -> [a] -> ExceptT e m a

A foldr1 that fails in the ExceptT monad

valuetryFoldl1 :: Monad m => e -> (a -> a -> a) -> [a] -> ExceptT e m a

A foldl1 that fails in the ExceptT monad

valuetryFoldl1' :: Monad m => e -> (a -> a -> a) -> [a] -> ExceptT e m a

A foldl1' that fails in the ExceptT monad

valuetryAt :: Monad m => e -> [a] -> Int -> ExceptT e m a

A (!!) that fails in the ExceptT monad

valuetryRead :: (Monad m, Read a) => e -> String -> ExceptT e m a

A read that fails in the ExceptT monad

valuetryAssert :: Monad m => e -> Bool -> ExceptT e m ()

An assertion that fails in the ExceptT monad

valuetryJust :: Monad m => e -> Maybe a -> ExceptT e m a

A fromJust that fails in the ExceptT monad

valuetryRight :: Monad m => Either e a -> ExceptT e m a

A fromRight that fails in the ExceptT monad

MonadPlus-compatible functions

14 declarations

valuetailZ :: MonadPlus m => [a] -> m [a]

A tail that fails using mzero

valueinitZ :: MonadPlus m => [a] -> m [a]

An init that fails using mzero

valueheadZ :: MonadPlus m => [a] -> m a

A head that fails using mzero

valuelastZ :: MonadPlus m => [a] -> m a

A last that fails using mzero

valueminimumZ :: (MonadPlus m, Ord a) => [a] -> m a

A minimum that fails using mzero

valuemaximumZ :: (MonadPlus m, Ord a) => [a] -> m a

A maximum that fails using mzero

valuefoldr1Z :: MonadPlus m => (a -> a -> a) -> [a] -> m a

A foldr1 that fails using mzero

valuefoldl1Z :: MonadPlus m => (a -> a -> a) -> [a] -> m a

A foldl1 that fails using mzero

valuefoldl1Z' :: MonadPlus m => (a -> a -> a) -> [a] -> m a

A foldl1' that fails using mzero

valueatZ :: MonadPlus m => [a] -> Int -> m a

A (!!) that fails using mzero

valuereadZ :: (MonadPlus m, Read a) => String -> m a

A read that fails using mzero

valueassertZ :: MonadPlus m => Bool -> m ()

An assertion that fails using mzero

valuejustZ :: MonadPlus m => Maybe a -> m a

A fromJust that fails using mzero

valuerightZ :: MonadPlus m => Either e a -> m a

A fromRight that fails using mzero