-- * Arrows
Arrow(..), Kleisli(..),
-- ** Derived combinators
- returnA, (<<<),
+ returnA,
+ (^>>), (>>^),
+ -- ** Right-to-left variants
+ (<<<), (<<^), (^<<),
-- * Monoid operations
ArrowZero(..), ArrowPlus(..),
-- * Conditionals
infixr 3 &&&
infixr 2 +++
infixr 2 |||
-infixr 1 >>>
-infixr 1 <<<
+infixr 1 >>>, ^>>, >>^
+infixr 1 <<<, ^<<, <<^
-- | The basic arrow class.
-- Any instance must define either 'arr' or 'pure' (which are synonyms),
returnA :: Arrow a => a b b
returnA = arr id
--- | Right-to-left composition, for a better fit with arrow notation.
+-- | Precomposition with a pure function.
+(^>>) :: Arrow a => (b -> c) -> a c d -> a b d
+f ^>> a = arr f >>> a
+
+-- | Postcomposition with a pure function.
+(>>^) :: Arrow a => a b c -> (c -> d) -> a b d
+a >>^ f = a >>> arr f
+-- | Right-to-left composition, for a better fit with arrow notation.
(<<<) :: Arrow a => a c d -> a b c -> a b d
f <<< g = g >>> f
+-- | Precomposition with a pure function (right-to-left variant).
+(<<^) :: Arrow a => a c d -> (b -> c) -> a b d
+a <<^ f = a <<< arr f
+
+-- | Postcomposition with a pure function (right-to-left variant).
+(^<<) :: Arrow a => (c -> d) -> a b c -> a b d
+f ^<< a = arr f <<< a
+
class Arrow a => ArrowZero a where
zeroArrow :: a b c