hablapps / dontfeartheprofunctoroptics

Don't Fear the Profunctor Optics!

Don't Fear the Profunctor Optics!

This is a series of posts on Profunctor Optics. They're heavily inspired on this awesome article by Pickering et al. Our contribution relies on providing box diagrams to make profunctor and profunctor optics easier to approach.

• Part I: Optics, Concretely
• Part II: Profunctors
• Part III: Profunctor Optics

Any feedback is welcome!

dontfeartheprofunctoroptics's Issues

Can one write an instance of Cartesian for DownStar

I don't think there is an valid implementation of Cartesian for DownStar. I cannot find it in the profunctors library . If so, maybe it is worth mentioning that it is impossible for write an instance of Cartesian for DownStar.

BTW I enjoy the serial very much, thank you for putting it together.

Lens type deeper explanation

Hello
I'm new in Opticts, could you clary if am i correct that the type parameters mean

data Lens s t a b = Lens { view :: s -> a
, update :: (b, s) -> t }

-- "s" whole data
-- "t" whole new data
-- "a" focus related to "s"
-- "b" focus related to "t"

is it correct ?

Thank you