Move Data.Functor.Contravariant into base

[Andrew Martin]

The reverse dependency count can be found here:
http://packdeps.haskellers.com/reverse

The contravariant library has 73 reverse dependencies. Just as a
reference point, bifunctors currently has 112 dependencies, and
Data.Bifunctor was moved into base-4.9. Whether or not you believe that
73 reverse deps is sufficient is up to you, but those are the most
relevant numbers I can provide.

-Andrew Martin

On Tue, Dec 13, 2016 at 09:34:13PM +0100, Andreas Abel wrote:
> -1.  I think to move something into base there should be some hard evidence
> for its popularity.  Such could be provided by a reverse dependency search
> on hackage.
> 
> --Andreas
> 
> On 11.12.2016 17:14, Andrew Martin wrote:
> >The typeclass Contravariant (from the contravariant package) is both
> >useful and fundamental. I would like to see this moved into base.
> >One additional motivating factor is that it would become possible
> >for a DeriveContravariant extension to be written in a future GHC
> >release.  I'd love to hear other people's thoughts, even if it's as
> >simple as a yea or nay. Thanks.
> >
> >-Andrew Martin
> >_______________________________________________
> >Libraries mailing list
> >Libraries at haskell.org
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> >
> 
> 
> -- 
> 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/