duncan.coutts:
On Sun, 2006-10-29 at 14:57 -0500, kahl@cas.mcmaster.ca wrote:
On 2006-10-29 at 09:30EST kahl@cas.mcmaster.ca wrote:
Speaking of small functions, Kleisli composition should at least be in Control.Monad. It's a simple thing, and not commonly explicitly used at the moment, but rather important conceptually.
(@@) :: (Monad m) => (b -> m c) -> (a -> m b) -> (a -> m c) g @@ f = \x -> f x >>= g
I support this strongly.
My notation is (=>>=), to go with (>>=).
That's a better symbol for it. (@@) could be just about anything, while (=>>=) is suggestive. Though I think what it suggests might be with the arguments in a different order?
Yes, indeed! Thanks for pointing this out! And I definitely prefer that order:
(=>>=) :: (a -> m b) -> (b -> m c) -> (a -> m c)
Ok. Let's have both (=>>=) and (=<<=).
If that's a consensus, then someone make a darcs patch with haddock documentation and a trac bug etc.
Before I or someone else rolls a patch for this, are there any other similar functions that fit? I'm reminded of some of the things from the old Gofer CC prelude, http://www.cse.unsw.edu.au/~dons/data/cc.prelude (@@) :: Monad m => (a -> m b) -> (c -> m a) -> (c -> m b) f @@ g = join . map f . g Do we have some references in the literature (a Mark Jones paper perhaps?) -- Don