Safe Haskell	Safe-Inferred
Language	Haskell98

Options.Applicative.Arrows

Description

This module contains an arrow interface for option parsers, which allows to define and combine parsers using the arrow notation and arrow combinators.

The arrow syntax is particularly useful to create parsers of nested structures, or records where the order of fields is different from the order in which the parsers should be applied.

For example, an arguments parser often needs to be applied last, and that makes it inconvenient to use it for a field which is not the last one in a record.

Using the arrow syntax and the functions in this module, one can write, e.g.:

data Options = Options
  { optArgs :: [String]
  , optVerbose :: Bool }

opts :: Parser Options
opts = runA $ proc () -> do
  verbose <- asA (switch (short 'v')) -< ()
  args <- asA (arguments str idm) -< ()
  returnA -< Options args verbose

Parser arrows, created out of regular Parser values using the asA function, are arrows taking () as argument and returning the parsed value.

Synopsis

class Category a => Arrow (a :: Type -> Type -> Type) where
- arr :: (b -> c) -> a b c
- first :: a b c -> a (b, d) (c, d)
- second :: a b c -> a (d, b) (d, c)
- (***) :: a b c -> a b' c' -> a (b, b') (c, c')
- (&&&) :: a b c -> a b c' -> a b (c, c')
class ArrowZero a => ArrowPlus (a :: Type -> Type -> Type) where
- (<+>) :: a b c -> a b c -> a b c
class Arrow a => ArrowLoop (a :: Type -> Type -> Type) where
- loop :: a (b, d) (c, d) -> a b c
class Arrow a => ArrowZero (a :: Type -> Type -> Type) where
- zeroArrow :: a b c
(>>>) :: forall {k} cat (a :: k) (b :: k) (c :: k). Category cat => cat a b -> cat b c -> cat a c
class Arrow a => ArrowChoice (a :: Type -> Type -> Type) where
- left :: a b c -> a (Either b d) (Either c d)
- right :: a b c -> a (Either d b) (Either d c)
- (+++) :: a b c -> a b' c' -> a (Either b b') (Either c c')
- (|||) :: a b d -> a c d -> a (Either b c) d
class Arrow a => ArrowApply (a :: Type -> Type -> Type) where
- app :: a (a b c, b) c
(<<<) :: forall {k} cat (b :: k) (c :: k) (a :: k). Category cat => cat b c -> cat a b -> cat a c
(<<^) :: Arrow a => a c d -> (b -> c) -> a b d
(>>^) :: Arrow a => a b c -> (c -> d) -> a b d
(^<<) :: Arrow a => (c -> d) -> a b c -> a b d
(^>>) :: Arrow a => (b -> c) -> a c d -> a b d
newtype Kleisli (m :: Type -> Type) a b = Kleisli {
- runKleisli :: a -> m b
}
newtype ArrowMonad (a :: Type -> Type -> Type) b = ArrowMonad (a () b)
leftApp :: ArrowApply a => a b c -> a (Either b d) (Either c d)
returnA :: Arrow a => a b b
newtype A (f :: Type -> Type) a b = A {
- unA :: f (a -> b)
}
asA :: Applicative f => f a -> A f () a
runA :: Applicative f => A f () a -> f a
type ParserA = A Parser

Documentation

class Category a => Arrow (a :: Type -> Type -> Type) where #

Minimal complete definition

arr, (first | (***))

Methods

arr :: (b -> c) -> a b c #

first :: a b c -> a (b, d) (c, d) #

second :: a b c -> a (d, b) (d, c) #

(***) :: a b c -> a b' c' -> a (b, b') (c, c') #

(&&&) :: a b c -> a b c' -> a b (c, c') #

Instances

Instances details

Monad m => Arrow (Kleisli m)
Instance details Defined in Control.Arrow Methods arr :: (b -> c) -> Kleisli m b c # first :: Kleisli m b c -> Kleisli m (b, d) (c, d) # second :: Kleisli m b c -> Kleisli m (d, b) (d, c) # (***) :: Kleisli m b c -> Kleisli m b' c' -> Kleisli m (b, b') (c, c') # (&&&) :: Kleisli m b c -> Kleisli m b c' -> Kleisli m b (c, c') #
Applicative f => Arrow (A f) Source #
Instance details Defined in Options.Applicative.Arrows Methods arr :: (b -> c) -> A f b c # first :: A f b c -> A f (b, d) (c, d) # second :: A f b c -> A f (d, b) (d, c) # (***) :: A f b c -> A f b' c' -> A f (b, b') (c, c') # (&&&) :: A f b c -> A f b c' -> A f b (c, c') #
Arrow (->)
Instance details Defined in Control.Arrow Methods arr :: (b -> c) -> b -> c # first :: (b -> c) -> (b, d) -> (c, d) # second :: (b -> c) -> (d, b) -> (d, c) # (***) :: (b -> c) -> (b' -> c') -> (b, b') -> (c, c') # (&&&) :: (b -> c) -> (b -> c') -> b -> (c, c') #

class ArrowZero a => ArrowPlus (a :: Type -> Type -> Type) where #

Methods

(<+>) :: a b c -> a b c -> a b c #

Instances

Instances details

MonadPlus m => ArrowPlus (Kleisli m)
Instance details Defined in Control.Arrow Methods (<+>) :: Kleisli m b c -> Kleisli m b c -> Kleisli m b c #

class Arrow a => ArrowLoop (a :: Type -> Type -> Type) where #

Methods

loop :: a (b, d) (c, d) -> a b c #

Instances

Instances details

MonadFix m => ArrowLoop (Kleisli m)
Instance details Defined in Control.Arrow Methods loop :: Kleisli m (b, d) (c, d) -> Kleisli m b c #
ArrowLoop (->)
Instance details Defined in Control.Arrow Methods loop :: ((b, d) -> (c, d)) -> b -> c #

class Arrow a => ArrowZero (a :: Type -> Type -> Type) where #

Methods

zeroArrow :: a b c #

Instances

Instances details

MonadPlus m => ArrowZero (Kleisli m)
Instance details Defined in Control.Arrow Methods zeroArrow :: Kleisli m b c #

(>>>) :: forall {k} cat (a :: k) (b :: k) (c :: k). Category cat => cat a b -> cat b c -> cat a c #

class Arrow a => ArrowChoice (a :: Type -> Type -> Type) where #

Minimal complete definition

(left | (+++))

Methods

left :: a b c -> a (Either b d) (Either c d) #

right :: a b c -> a (Either d b) (Either d c) #

(+++) :: a b c -> a b' c' -> a (Either b b') (Either c c') #

(|||) :: a b d -> a c d -> a (Either b c) d #

Instances

Instances details

Monad m => ArrowChoice (Kleisli m)
Instance details Defined in Control.Arrow Methods left :: Kleisli m b c -> Kleisli m (Either b d) (Either c d) # right :: Kleisli m b c -> Kleisli m (Either d b) (Either d c) # (+++) :: Kleisli m b c -> Kleisli m b' c' -> Kleisli m (Either b b') (Either c c') # (\|\|\|) :: Kleisli m b d -> Kleisli m c d -> Kleisli m (Either b c) d #
ArrowChoice (->)
Instance details Defined in Control.Arrow Methods left :: (b -> c) -> Either b d -> Either c d # right :: (b -> c) -> Either d b -> Either d c # (+++) :: (b -> c) -> (b' -> c') -> Either b b' -> Either c c' # (\|\|\|) :: (b -> d) -> (c -> d) -> Either b c -> d #

class Arrow a => ArrowApply (a :: Type -> Type -> Type) where #

Methods

app :: a (a b c, b) c #

Instances

Instances details

Monad m => ArrowApply (Kleisli m)
Instance details Defined in Control.Arrow Methods app :: Kleisli m (Kleisli m b c, b) c #
ArrowApply (->)
Instance details Defined in Control.Arrow Methods app :: (b -> c, b) -> c #

(<<<) :: forall {k} cat (b :: k) (c :: k) (a :: k). Category cat => cat b c -> cat a b -> cat a c #

(<<^) :: Arrow a => a c d -> (b -> c) -> a b d #

(>>^) :: Arrow a => a b c -> (c -> d) -> a b d #

(^<<) :: Arrow a => (c -> d) -> a b c -> a b d #

(^>>) :: Arrow a => (b -> c) -> a c d -> a b d #

newtype Kleisli (m :: Type -> Type) a b #

Constructors

Kleisli
Fields runKleisli :: a -> m b

Instances

Instances details

Monad m => Category (Kleisli m :: Type -> Type -> Type)

Instance details

ArrowPlus a => Alternative (ArrowMonad a)
Instance details Defined in Control.Arrow Methods empty :: ArrowMonad a a0 # (<\|>) :: ArrowMonad a a0 -> ArrowMonad a a0 -> ArrowMonad a a0 # some :: ArrowMonad a a0 -> ArrowMonad a [a0] # many :: ArrowMonad a a0 -> ArrowMonad a [a0] #
Arrow a => Applicative (ArrowMonad a)
Instance details Defined in Control.Arrow Methods pure :: a0 -> ArrowMonad a a0 # (<>) :: ArrowMonad a (a0 -> b) -> ArrowMonad a a0 -> ArrowMonad a b # liftA2 :: (a0 -> b -> c) -> ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a c # (>) :: ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a b # (<*) :: ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a a0 #
Arrow a => Functor (ArrowMonad a)
Instance details Defined in Control.Arrow Methods fmap :: (a0 -> b) -> ArrowMonad a a0 -> ArrowMonad a b (<$) :: a0 -> ArrowMonad a b -> ArrowMonad a a0 #
ArrowApply a => Monad (ArrowMonad a)
Instance details Defined in Control.Arrow Methods (>>=) :: ArrowMonad a a0 -> (a0 -> ArrowMonad a b) -> ArrowMonad a b (>>) :: ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a b return :: a0 -> ArrowMonad a a0
(ArrowApply a, ArrowPlus a) => MonadPlus (ArrowMonad a)
Instance details Defined in Control.Arrow Methods mzero :: ArrowMonad a a0 mplus :: ArrowMonad a a0 -> ArrowMonad a a0 -> ArrowMonad a a0

Applicative f => Category (A f :: Type -> Type -> Type) Source #
Instance details Defined in Options.Applicative.Arrows Methods id :: A f a a (.) :: A f b c -> A f a b -> A f a c
Applicative f => Arrow (A f) Source #
Instance details Defined in Options.Applicative.Arrows Methods arr :: (b -> c) -> A f b c # first :: A f b c -> A f (b, d) (c, d) # second :: A f b c -> A f (d, b) (d, c) # (***) :: A f b c -> A f b' c' -> A f (b, b') (c, c') # (&&&) :: A f b c -> A f b c' -> A f b (c, c') #

A
Fields unA :: f (a -> b)