You may be interested in this paper:
Idioms are oblivious, arrows are meticulous, monads are promiscuous
http://homepages.inf.ed.ac.uk/wadler/papers/arrows-and-idioms/arrows-and-idi...
"Idioms" refers to the Applicative class.
To put it briefly, if you have an instance of Arrow, you also have an
automatic instance for Applicative, which I brought up about a month ago on
reddit:
http://www.reddit.com/r/haskell/comments/1ivd23/default_functor_and_applicat...
-- Dan Burton
On Fri, Aug 16, 2013 at 7:52 AM, Brandon Allbery
On Fri, Aug 16, 2013 at 10:49 AM, Tom Ellis < tom-lists-haskell-cafe-2013@jaguarpaw.co.uk> wrote:
On Fri, Aug 16, 2013 at 10:26:42AM -0400, Brandon Allbery wrote:
My understanding is that there's a rework of Arrow in progress that may change this in the future, since *theoretical* Arrows are more distinct, flexible and useful than the current implementation.
I'd like to know more about that if you can provide any references. I am using arrows very heavily.
It's been mentioned (but not much more) in #haskell IRC, so I don't know details. I also expect it's not going to simply replace the current one, at least not initially; and I think it's supposed to maintain compatibility with the current Arrow because that's just a specialization to the function arrow.
-- brandon s allbery kf8nh sine nomine associates allbery.b@gmail.com ballbery@sinenomine.net unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net
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