pipes-3.2.0: Compositional pipelines

Safe HaskellSafe-Inferred

Control.Proxy.Prelude.Kleisli

Contents

Description

Utility functions for Kleisli arrows

Synopsis

Core utility functions

foreverK :: Monad m => (a -> m a) -> a -> m bSource

Compose a 'K'leisli arrow with itself forever

Use foreverK to abstract away the following common recursion pattern: 

 p a = do
     ...
     a' <- respond b
     p a'

Using foreverK, you can instead write: 

 p = foreverK $ \a -> do
     ...
     respond b

replicateK :: Monad m => Int -> (a -> m a) -> a -> m aSource

Repeat a 'K'leisli arrow multiple times

liftK :: (Monad m, MonadTrans t) => (a -> m b) -> a -> t m bSource

Convenience function equivalent to (lift .) 

 liftK f >=> liftK g = liftK (f >=> g)

 liftK return = return

hoistKSource

Arguments

:: (Monad m, MFunctor t) 
=> (forall a. m a -> n a)

Monad morphism

-> (b' -> t m b)

Kleisli arrow

-> b' -> t n b 

Convenience function equivalent to (hoist f .)

raise :: (Monad m, MFunctor t1, MonadTrans t2) => t1 m r -> t1 (t2 m) rSource

Lift the base monad 

 raise = hoist lift

raiseK :: (Monad m, MFunctor t1, MonadTrans t2) => (q -> t1 m r) -> q -> t1 (t2 m) rSource

Lift the base monad of a 'K'leisli arrow 

 raiseK = hoistK lift

hoistPKSource

Arguments

:: (Monad m, Proxy p1, PFunctor t) 
=> (forall r1. p1 a' a b' b m r1 -> p2 a' a b' b n r1)

Proxy morphism

-> (q -> t p1 a' a b' b m r2)

Proxy Kleisli arrow

-> q -> t p2 a' a b' b n r2 

Convenience function equivalent to (hoistP f .)

raisePSource

Arguments

:: (Monad m, Proxy p, PFunctor t1, ProxyTrans t2) 
=> t1 p a' a b' b m r

Proxy

-> t1 (t2 p) a' a b' b m r 

Lift the base proxy 

 raiseP = hoistP liftP

raisePKSource

Arguments

:: (Monad m, Proxy p, PFunctor t1, ProxyTrans t2) 
=> (q -> t1 p a' a b' b m r)

Proxy Kleisli arrow

-> q -> t1 (t2 p) a' a b' b m r 

Lift the base proxy of a 'K'leisli arrow 

 raisePK = hoistPK liftP