adds a contravariant functor to spec

[rjmk]

See fantasyland/fantasy-land#150

Resolves #15

[coveralls]

Coverage remained the same at 31.667% when pulling 3591965 on rjmk:master into 1850c6c on rpominov:master.

[rpominov]

Thanks! Let's see how fantasyland/fantasy-land#150 go.

[rjmk]

👍

[coveralls]

Coverage remained the same at 31.667% when pulling 7482b25 on rjmk:master into 1850c6c on rpominov:master.

[rjmk]

Still interested in this now it's merged in FL? If so, I'll spend some time getting it up to date

[rpominov]

Yea, definitely interested. Please do!

[rjmk]

I appear to have stolen your profile picture, @rpominov. Sorry about that

I think this is updated! No diagram (my arch nemesis in FL PRs)

[rpominov]

Thank you! I'll take a close look tomorrow and hopefully merge.

I appear to have stolen your profile picture, @rpominov. Sorry about that

Haha, not quite the same though 😅

[rpominov]

It should be contramap :: Contravariant f => Type f ~> (a → b, f b) → f a.

This notations probably doesn't make much sense to anyone but me, and I don't like it too much either. But for now we should use it in all methods for consistency.

[rjmk]

⚡️

[rpominov]

Thank you!