Control.Selective.Trans.Except

This is a library for selective applicative functors, or just selective functors for short, an abstraction between applicative functors and monads, introduced in this paper: https://www.staff.ncl.ac.uk/andrey.mokhov/selective-functors.pdf.

This module defines a newtype around ExceptT from transformers with less restrictive Applicative, Selective, and Alternative implementations. It supplies an instance Selective f => Selective (ExceptT e f), which makes ExceptT a bona-fide Selective transformer.

The API follows the API from the transformers package, so it can be used as a drop-in replacement. The documentation can be found in the transformers package.

Documentation

newtype ExceptT e f a

A newtype wrapper around ExceptT from transformers that provides less restrictive Applicative, Selective and Alternative instances.

Constructors

ExceptT

Fields

• unwrap :: ExceptT e f a

Instances

(Selective f, MonadFail f) => MonadFail (ExceptT e f)

Defined in Control.Selective.Trans.Except

Methods

fail :: String -> ExceptT e f a

(Selective f, MonadFix f) => MonadFix (ExceptT e f)

Defined in Control.Selective.Trans.Except

Methods

mfix :: (a -> ExceptT e f a) -> ExceptT e f a

(Selective f, MonadIO f) => MonadIO (ExceptT e f)

Defined in Control.Selective.Trans.Except

Methods

liftIO :: IO a -> ExceptT e f a

(Selective f, MonadZip f) => MonadZip (ExceptT e f)

Defined in Control.Selective.Trans.Except

Methods

mzip :: ExceptT e f a -> ExceptT e f b -> ExceptT e f (a, b)

mzipWith :: (a -> b -> c) -> ExceptT e f a -> ExceptT e f b -> ExceptT e f c

munzip :: ExceptT e f (a, b) -> (ExceptT e f a, ExceptT e f b)

Foldable f => Foldable (ExceptT e f)

Defined in Control.Selective.Trans.Except

Methods

fold :: Monoid m => ExceptT e f m -> m

foldMap :: Monoid m => (a -> m) -> ExceptT e f a -> m

foldMap' :: Monoid m => (a -> m) -> ExceptT e f a -> m

foldr :: (a -> b -> b) -> b -> ExceptT e f a -> b

foldr' :: (a -> b -> b) -> b -> ExceptT e f a -> b

foldl :: (b -> a -> b) -> b -> ExceptT e f a -> b

foldl' :: (b -> a -> b) -> b -> ExceptT e f a -> b

foldr1 :: (a -> a -> a) -> ExceptT e f a -> a

foldl1 :: (a -> a -> a) -> ExceptT e f a -> a

toList :: ExceptT e f a -> [a]

null :: ExceptT e f a -> Bool

length :: ExceptT e f a -> Int

elem :: Eq a => a -> ExceptT e f a -> Bool

maximum :: Ord a => ExceptT e f a -> a

minimum :: Ord a => ExceptT e f a -> a

sum :: Num a => ExceptT e f a -> a

product :: Num a => ExceptT e f a -> a

(Eq e, Eq1 f) => Eq1 (ExceptT e f)

Defined in Control.Selective.Trans.Except

Methods

liftEq :: (a -> b -> Bool) -> ExceptT e f a -> ExceptT e f b -> Bool

(Ord e, Ord1 f) => Ord1 (ExceptT e f)

Defined in Control.Selective.Trans.Except

Methods

liftCompare :: (a -> b -> Ordering) -> ExceptT e f a -> ExceptT e f b -> Ordering

(Read e, Read1 f) => Read1 (ExceptT e f)

Defined in Control.Selective.Trans.Except

Methods

liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (ExceptT e f a)

liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [ExceptT e f a]

liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (ExceptT e f a)

liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [ExceptT e f a]

(Show e, Show1 f) => Show1 (ExceptT e f)

Defined in Control.Selective.Trans.Except

Methods

liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> ExceptT e f a -> ShowS

liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [ExceptT e f a] -> ShowS

Contravariant f => Contravariant (ExceptT e f)

Defined in Control.Selective.Trans.Except

Methods

contramap :: (a' -> a) -> ExceptT e f a -> ExceptT e f a'

(>$) :: b -> ExceptT e f b -> ExceptT e f a

Traversable f => Traversable (ExceptT e f)

Defined in Control.Selective.Trans.Except

Methods

traverse :: Applicative f0 => (a -> f0 b) -> ExceptT e f a -> f0 (ExceptT e f b)

sequenceA :: Applicative f0 => ExceptT e f (f0 a) -> f0 (ExceptT e f a)

mapM :: Monad m => (a -> m b) -> ExceptT e f a -> m (ExceptT e f b)

sequence :: Monad m => ExceptT e f (m a) -> m (ExceptT e f a)

(Selective f, Monoid e) => Alternative (ExceptT e f)

Defined in Control.Selective.Trans.Except

Methods

empty :: ExceptT e f a

(<|>) :: ExceptT e f a -> ExceptT e f a -> ExceptT e f a

some :: ExceptT e f a -> ExceptT e f [a]

many :: ExceptT e f a -> ExceptT e f [a]

Selective f => Applicative (ExceptT e f)

Defined in Control.Selective.Trans.Except

Methods

pure :: a -> ExceptT e f a

(<*>) :: ExceptT e f (a -> b) -> ExceptT e f a -> ExceptT e f b

liftA2 :: (a -> b -> c) -> ExceptT e f a -> ExceptT e f b -> ExceptT e f c

(*>) :: ExceptT e f a -> ExceptT e f b -> ExceptT e f b

(<*) :: ExceptT e f a -> ExceptT e f b -> ExceptT e f a

Functor f => Functor (ExceptT e f)

Defined in Control.Selective.Trans.Except

Methods

fmap :: (a -> b) -> ExceptT e f a -> ExceptT e f b

(<$) :: a -> ExceptT e f b -> ExceptT e f a

(Selective f, Monad f) => Monad (ExceptT e f)

Defined in Control.Selective.Trans.Except

Methods

(>>=) :: ExceptT e f a -> (a -> ExceptT e f b) -> ExceptT e f b

(>>) :: ExceptT e f a -> ExceptT e f b -> ExceptT e f b

return :: a -> ExceptT e f a

(Selective f, Monoid e, Monad f) => MonadPlus (ExceptT e f)

Defined in Control.Selective.Trans.Except

Methods

mzero :: ExceptT e f a

mplus :: ExceptT e f a -> ExceptT e f a -> ExceptT e f a

Selective f => Selective (ExceptT e f)

Defined in Control.Selective.Trans.Except

Methods

select :: ExceptT e f (Either a b) -> ExceptT e f (a -> b) -> ExceptT e f b

(Read1 f, Read e, Read a) => Read (ExceptT e f a)

Defined in Control.Selective.Trans.Except

Methods

readsPrec :: Int -> ReadS (ExceptT e f a)

readList :: ReadS [ExceptT e f a]

readPrec :: ReadPrec (ExceptT e f a)

readListPrec :: ReadPrec [ExceptT e f a]

(Show1 f, Show e, Show a) => Show (ExceptT e f a)

Defined in Control.Selective.Trans.Except

Methods

showsPrec :: Int -> ExceptT e f a -> ShowS

show :: ExceptT e f a -> String

showList :: [ExceptT e f a] -> ShowS

(Eq1 f, Eq e, Eq a) => Eq (ExceptT e f a)

Defined in Control.Selective.Trans.Except

Methods

(==) :: ExceptT e f a -> ExceptT e f a -> Bool

(/=) :: ExceptT e f a -> ExceptT e f a -> Bool

(Ord1 f, Ord e, Ord a) => Ord (ExceptT e f a)

Defined in Control.Selective.Trans.Except

Methods

compare :: ExceptT e f a -> ExceptT e f a -> Ordering

(<) :: ExceptT e f a -> ExceptT e f a -> Bool

(<=) :: ExceptT e f a -> ExceptT e f a -> Bool

(>) :: ExceptT e f a -> ExceptT e f a -> Bool

(>=) :: ExceptT e f a -> ExceptT e f a -> Bool

max :: ExceptT e f a -> ExceptT e f a -> ExceptT e f a

min :: ExceptT e f a -> ExceptT e f a -> ExceptT e f a

wrap :: ExceptT e m a -> ExceptT e m a

Inject an ExceptT value into the newtype wrapper.

type Except e = ExceptT e Identity

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

runExcept :: Except e a -> Either e a

mapExcept :: (Either e a -> Either e' b) -> Except e a -> Except e' b

withExcept :: (e -> e') -> Except e a -> Except e' a

runExceptT :: ExceptT e m a -> m (Either e a)

mapExceptT :: (m (Either e a) -> n (Either e' b)) -> ExceptT e m a -> ExceptT e' n b

withExceptT :: Functor m => (e -> e') -> ExceptT e m a -> ExceptT e' m a

throwE :: Monad m => e -> ExceptT e m a

catchE :: Monad m => ExceptT e m a -> (e -> ExceptT e' m a) -> ExceptT e' m a

liftCallCC :: CallCC m (Either e a) (Either e b) -> CallCC (ExceptT e m) a b

liftListen :: Monad m => Listen w m (Either e a) -> Listen w (ExceptT e m) a

liftPass :: Monad m => Pass w m (Either e a) -> Pass w (ExceptT e m) a