<div dir="ltr">You may be interested in this paper:<div><br></div><div><div>Idioms are oblivious, arrows are meticulous, monads are promiscuous</div></div><div><a href="http://homepages.inf.ed.ac.uk/wadler/papers/arrows-and-idioms/arrows-and-idioms.pdf">http://homepages.inf.ed.ac.uk/wadler/papers/arrows-and-idioms/arrows-and-idioms.pdf</a><br>
</div><div><br></div><div>"Idioms" refers to the Applicative class.</div><div><br></div><div>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:</div>
<div><a href="http://www.reddit.com/r/haskell/comments/1ivd23/default_functor_and_applicative_instances_for/">http://www.reddit.com/r/haskell/comments/1ivd23/default_functor_and_applicative_instances_for/</a><br></div><div>
<br></div></div><div class="gmail_extra"><br clear="all"><div>-- Dan Burton</div>
<br><br><div class="gmail_quote">On Fri, Aug 16, 2013 at 7:52 AM, Brandon Allbery <span dir="ltr"><<a href="mailto:allbery.b@gmail.com" target="_blank">allbery.b@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr"><div class="im">On Fri, Aug 16, 2013 at 10:49 AM, Tom Ellis <span dir="ltr"><<a href="mailto:tom-lists-haskell-cafe-2013@jaguarpaw.co.uk" target="_blank">tom-lists-haskell-cafe-2013@jaguarpaw.co.uk</a>></span> wrote:<br>
</div><div class="gmail_extra"><div class="gmail_quote"><div class="im"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div>On Fri, Aug 16, 2013 at 10:26:42AM -0400, Brandon Allbery wrote:<br>
> My understanding is that there's a rework of Arrow in progress that may<br>
> change this in the future, since *theoretical* Arrows are more distinct,<br>
> flexible and useful than the current implementation.<br>
<br>
</div>I'd like to know more about that if you can provide any references. I am using<br>
arrows very heavily.<br></blockquote><div><br></div></div><div>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.</div>
</div><div class="im"><div><br></div>-- <br><div dir="ltr"><div>brandon s allbery kf8nh sine nomine associates</div><div><a href="mailto:allbery.b@gmail.com" target="_blank">allbery.b@gmail.com</a> <a href="mailto:ballbery@sinenomine.net" target="_blank">ballbery@sinenomine.net</a></div>
<div>unix, openafs, kerberos, infrastructure, xmonad <a href="http://sinenomine.net" target="_blank">http://sinenomine.net</a></div></div>
</div></div></div>
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