>>> let s = Success 0
>>> let e = Error "critical"
>>> result ("Bad: " ++) (("OK: " ++) . show) s
"OK: 0"
>>> result ("Bad: " ++) (("OK: " ++) . show) e
"Bad: critical"

fromEither :: Either String a -> Result a Source #

Convert Either String a to Result a.

toEither :: Result a -> Either String a Source #

Convert Result a to Either String a.

fromSuccess :: a -> Result a -> a Source #

Convert Result a to a with a default value.

toMonadFail :: MonadFail m => Result a -> m a Source #

Convert Result a to MonadFail m => m a.

The ResultT monad transformer

data ResultT m a Source #

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

MonadFail = ResultT . throwE

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))))

pattern ResultT :: Functor m => m (Result a) -> ResultT m a Source #

Construct and destruct Result.

runResultT :: Functor m => ResultT m a -> m (Result a) Source #

Unwrap ResultT.

mapResultT :: (Functor m, Functor n) => (m (Result a) -> n (Result 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.

Orphan instances

Read a => Read (Result a) Source #
Instance details 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 Methods showsPrec :: Int -> Result a -> ShowS # show :: Result a -> String # showList :: [Result a] -> ShowS #
Semigroup (Result a) Source #
Instance details 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 Methods mempty :: Result a # mappend :: Result a -> Result a -> Result a # mconcat :: [Result a] -> Result a #