[Haskell-cafe] Control.Arrow being icky

Louis Wasserman wasserman.louis at gmail.com
Mon Feb 9 13:10:45 EST 2009


In GHCi, I import Control.Arrow, and Kliesli doesn't appear:
Prelude Control.Arrow> :t Kliesli

<interactive>:1:0: Not in scope: data constructor `Kliesli'
Prelude Control.Arrow> :browse
(<<^) :: (Arrow a) => a c d -> (b -> c) -> a b d
(>>^) :: (Arrow a) => a b c -> (c -> d) -> a b d
class (Control.Category.Category a) => Arrow a 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 (Arrow a) => ArrowApply a where app :: a (a b c, b) c
class (Arrow a) => ArrowChoice a 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) => ArrowLoop a where
  loop :: a (b, d) (c, d) -> a b c
newtype (ArrowApply a) => ArrowMonad a b = ArrowMonad (a () b)
class (ArrowZero a) => ArrowPlus a where
  (<+>) :: a b c -> a b c -> a b c
class (Arrow a) => ArrowZero a where zeroArrow :: a b c
newtype Kleisli m a b = Kleisli {runKleisli :: a -> m b}
(^<<) :: (Arrow a) => (c -> d) -> a b c -> a b d
(^>>) :: (Arrow a) => (b -> c) -> a c d -> a b d
leftApp :: (ArrowApply a) => a b c -> a (Either b d) (Either c d)
returnA :: (Arrow a) => a b b
(<<<) ::
  (Control.Category.Category cat) => cat b c -> cat a b -> cat a c
(>>>) ::
  (Control.Category.Category cat) => cat a b -> cat b c -> cat a c

Does anybody know what's going on?

Louis Wasserman
wasserman.louis at gmail.com
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