Proposal: add liftA4 and liftA5 to match liftM4 and liftM5

[Andreas Abel]

Agreed.  I never use liftMx or liftAx and when I see them in old code, I 
replace them by <$> and <*>.

Anyway, I like the proposal best that changes to constraint on liftM to 
Applicative, and leaves everything else alone.

I hope the same happens for sequence, mapM and the like!

   sequence :: (Applicative m) => [m a] -> m [a]
   sequence = foldr (\ x xs -> (:) <$> x <*> xs) (pure [])

On 06.11.2014 11:04, Michael Snoyman wrote:
>
>
> On Thu, Nov 6, 2014 at 11:50 AM, Henning Thielemann
> <lemming at henning-thielemann.de <mailto:lemming at henning-thielemann.de>>
> wrote:
>
>
>     On Thu, 6 Nov 2014, Michael Snoyman wrote:
>
>         David: I think the resistance you're seeing is coming from the
>         fact that- at least in my experience- liftMN
>         is not considered good, idiomatic Haskell code,
>
>
>     Who does not consider it good or idiomatic and why? Lifting things
>     through some stages of types is a common thing in Haskell, or not?
>
>
> I wasn't talking about lifting as a general concept, I was comparing to
> <$> and <*>. From what I've seen of Haskell code in general, people use
> the operators far more often, and tend to recommend them to new users.
>
> Michael
>
>
> _______________________________________________
> Libraries mailing list
> Libraries at haskell.org
> http://www.haskell.org/mailman/listinfo/libraries
>


-- 
Andreas Abel  <><      Du bist der geliebte Mensch.

Department of Computer Science and Engineering
Chalmers and Gothenburg University, Sweden

andreas.abel at gu.se
http://www2.tcs.ifi.lmu.de/~abel/