Safe Haskell	None
Language	Haskell2010
Extensions	Cpp DeriveFunctor DeriveTraversable DeriveFoldable DeriveGeneric DerivingStrategies GeneralizedNewtypeDeriving ExplicitNamespaces PatternSynonyms

Control.Monad.Trans.Except.Result

Contents

The Result monad
The ResultT monad transformer
Exception operations
Lifting other operations

Description

This monad transformer extends a monad with the ability to fail.

Synopsis

type Result = ResultT Identity
pattern Result :: Except String a -> Result a
runResult :: Result a -> Except String a
newtype ResultT m a = ResultT (ExceptT String m a)
runResultT :: ResultT m a -> ExceptT String m a
mapResultT :: (ExceptT String m a -> ExceptT String n b) -> ResultT m a -> ResultT n b
throwE :: Monad m => String -> ResultT m a
catchE :: Monad m => ResultT m a -> (String -> ResultT m a) -> ResultT m a
liftCallCC :: CallCC m (Either String a) (Either String b) -> CallCC (ResultT m) a b
liftListen :: Monad m => Listen w m (Either String a) -> Listen w (ResultT m) a
liftPass :: Monad m => Pass w m (Either String a) -> Pass w (ResultT m) a

The Result monad

type Result = ResultT Identity Source #

A result monad.

pattern Result :: Except String a -> Result a Source #

Wrap Except String a.

runResult :: Result a -> Except String a Source #

Unwrap Result a.

The ResultT monad transformer

newtype ResultT m a Source #

A monad transformer that is similar to ExceptT except a MonadFail instance.

MonadFail = ResultT . throwE

Constructors

ResultT (ExceptT String m a)

Instances

MonadTrans ResultT Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods lift :: Monad m => m a -> ResultT m a #
(MonadReader r m, MonadWriter w m, MonadState s m) => MonadRWS r w s (ResultT m) Source #
Instance details Defined in Control.Monad.Trans.Except.Result
MonadWriter w m => MonadWriter w (ResultT m) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods writer :: (a, w) -> ResultT m a # tell :: w -> ResultT m () # listen :: ResultT m a -> ResultT m (a, w) # pass :: ResultT m (a, w -> w) -> ResultT m a #
MonadState s m => MonadState s (ResultT m) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods get :: ResultT m s # put :: s -> ResultT m () # state :: (s -> (a, s)) -> ResultT m a #
MonadReader r m => MonadReader r (ResultT m) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods ask :: ResultT m r # local :: (r -> r) -> ResultT m a -> ResultT m a # reader :: (r -> a) -> ResultT m a #
Monad m => MonadError String (ResultT m) Source #
Instance details Defined in Control.Monad.Result Methods throwError :: String -> ResultT m a # catchError :: ResultT m a -> (String -> ResultT m a) -> ResultT m a #
Monad m => Monad (ResultT m) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods (>>=) :: ResultT m a -> (a -> ResultT m b) -> ResultT m b # (>>) :: ResultT m a -> ResultT m b -> ResultT m b # return :: a -> ResultT m a # fail :: String -> ResultT m a #
Functor m => Functor (ResultT m) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods fmap :: (a -> b) -> ResultT m a -> ResultT m b # (<$) :: a -> ResultT m b -> ResultT m a #
Read a => Read (Result a) Source #
Instance details Defined in Control.Monad.Trans.Result Methods readsPrec :: Int -> ReadS (Result a) # readList :: ReadS [Result a] # readPrec :: ReadPrec (Result a) # readListPrec :: ReadPrec [Result a] #
Show a => Show (Result a) Source #
Instance details Defined in Control.Monad.Trans.Result Methods showsPrec :: Int -> Result a -> ShowS # show :: Result a -> String # showList :: [Result a] -> ShowS #
MonadFix m => MonadFix (ResultT m) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods mfix :: (a -> ResultT m a) -> ResultT m a #
Monad m => MonadFail (ResultT m) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods fail :: String -> ResultT m a #
Monad m => Applicative (ResultT m) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods pure :: a -> ResultT m a # (<>) :: ResultT m (a -> b) -> ResultT m a -> ResultT m b # liftA2 :: (a -> b -> c) -> ResultT m a -> ResultT m b -> ResultT m c # (>) :: ResultT m a -> ResultT m b -> ResultT m b # (<*) :: ResultT m a -> ResultT m b -> ResultT m a #
Foldable m => Foldable (ResultT m) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods fold :: Monoid m0 => ResultT m m0 -> m0 # foldMap :: Monoid m0 => (a -> m0) -> ResultT m a -> m0 # foldr :: (a -> b -> b) -> b -> ResultT m a -> b # foldr' :: (a -> b -> b) -> b -> ResultT m a -> b # foldl :: (b -> a -> b) -> b -> ResultT m a -> b # foldl' :: (b -> a -> b) -> b -> ResultT m a -> b # foldr1 :: (a -> a -> a) -> ResultT m a -> a # foldl1 :: (a -> a -> a) -> ResultT m a -> a # toList :: ResultT m a -> [a] # null :: ResultT m a -> Bool # length :: ResultT m a -> Int # elem :: Eq a => a -> ResultT m a -> Bool # maximum :: Ord a => ResultT m a -> a # minimum :: Ord a => ResultT m a -> a # sum :: Num a => ResultT m a -> a # product :: Num a => ResultT m a -> a #
Traversable m => Traversable (ResultT m) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods traverse :: Applicative f => (a -> f b) -> ResultT m a -> f (ResultT m b) # sequenceA :: Applicative f => ResultT m (f a) -> f (ResultT m a) # mapM :: Monad m0 => (a -> m0 b) -> ResultT m a -> m0 (ResultT m b) # sequence :: Monad m0 => ResultT m (m0 a) -> m0 (ResultT m a) #
Semigroup (Result a) Source #
Instance details Defined in Control.Monad.Trans.Result Methods (<>) :: Result a -> Result a -> Result a # sconcat :: NonEmpty (Result a) -> Result a # stimes :: Integral b => b -> Result a -> Result a #
Monoid (Result a) Source #
Instance details Defined in Control.Monad.Trans.Result Methods mempty :: Result a # mappend :: Result a -> Result a -> Result a # mconcat :: [Result a] -> Result a #
Contravariant m => Contravariant (ResultT m) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods contramap :: (a -> b) -> ResultT m b -> ResultT m a # (>$) :: b -> ResultT m b -> ResultT m a #
Eq1 m => Eq1 (ResultT m) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods liftEq :: (a -> b -> Bool) -> ResultT m a -> ResultT m b -> Bool #
Ord1 m => Ord1 (ResultT m) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods liftCompare :: (a -> b -> Ordering) -> ResultT m a -> ResultT m b -> Ordering #
Read1 m => Read1 (ResultT m) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (ResultT m a) # liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [ResultT m a] # liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (ResultT m a) # liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [ResultT m a] #
Show1 m => Show1 (ResultT m) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> ResultT m a -> ShowS # liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [ResultT m a] -> ShowS #
MonadZip m => MonadZip (ResultT m) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods mzip :: ResultT m a -> ResultT m b -> ResultT m (a, b) # mzipWith :: (a -> b -> c) -> ResultT m a -> ResultT m b -> ResultT m c # munzip :: ResultT m (a, b) -> (ResultT m a, ResultT m b) #
MonadIO m => MonadIO (ResultT m) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods liftIO :: IO a -> ResultT m a #
Monad m => Alternative (ResultT m) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods empty :: ResultT m a # (<\|>) :: ResultT m a -> ResultT m a -> ResultT m a # some :: ResultT m a -> ResultT m [a] # many :: ResultT m a -> ResultT m [a] #
Monad m => MonadPlus (ResultT m) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods mzero :: ResultT m a # mplus :: ResultT m a -> ResultT m a -> ResultT m a #
MonadCont m => MonadCont (ResultT m) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods callCC :: ((a -> ResultT m b) -> ResultT m a) -> ResultT m a #
(Eq1 m, Eq a) => Eq (ResultT m a) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods (==) :: ResultT m a -> ResultT m a -> Bool # (/=) :: ResultT m a -> ResultT m a -> Bool #
(Ord1 m, Ord a) => Ord (ResultT m a) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods compare :: ResultT m a -> ResultT m a -> Ordering # (<) :: ResultT m a -> ResultT m a -> Bool # (<=) :: ResultT m a -> ResultT m a -> Bool # (>) :: ResultT m a -> ResultT m a -> Bool # (>=) :: ResultT m a -> ResultT m a -> Bool # max :: ResultT m a -> ResultT m a -> ResultT m a # min :: ResultT m a -> ResultT m a -> ResultT m a #
(Read1 m, Read a) => Read (ResultT m a) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods readsPrec :: Int -> ReadS (ResultT m a) # readList :: ReadS [ResultT m a] # readPrec :: ReadPrec (ResultT m a) # readListPrec :: ReadPrec [ResultT m a] #
(Show1 m, Show a) => Show (ResultT m a) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Methods showsPrec :: Int -> ResultT m a -> ShowS # show :: ResultT m a -> String # showList :: [ResultT m a] -> ShowS #
Generic (ResultT m a) Source #
Instance details Defined in Control.Monad.Trans.Except.Result Associated Types type Rep (ResultT m a) :: Type -> Type # Methods from :: ResultT m a -> Rep (ResultT m a) x # to :: Rep (ResultT m a) x -> ResultT m a #
type Rep (ResultT m a) Source #
Instance details Defined in Control.Monad.Trans.Except.Result type Rep (ResultT m a) = D1 (MetaData "ResultT" "Control.Monad.Trans.Except.Result" "either-result-0.3.1.0-5ZrbOcIF3a87s8MCX9Io9l" True) (C1 (MetaCons "ResultT" PrefixI True) (S1 (MetaSel (Just "runResultT") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (ExceptT String m a))))

runResultT :: ResultT m a -> ExceptT String m a Source #

Unwrap ResultT m a.

mapResultT :: (ExceptT String m a -> ExceptT String n b) -> ResultT m a -> ResultT n b Source #

Map the unwrapped computation using the given function.

Exception operations

throwE :: Monad m => String -> ResultT m a Source #

Signal an exception.

catchE :: Monad m => ResultT m a -> (String -> ResultT m a) -> ResultT m a Source #

Handle an exception.

Lifting other operations

liftCallCC :: CallCC m (Either String a) (Either String b) -> CallCC (ResultT m) a b Source #

Lift a callCC operation to the new monad.

liftListen :: Monad m => Listen w m (Either String a) -> Listen w (ResultT m) a Source #

Lift a listen operation to the new monad.

liftPass :: Monad m => Pass w m (Either String a) -> Pass w (ResultT m) a Source #

Lift a pass operation to the new monad.