Profunctor should require Contravariant

[Ne4to777]

I think it should be something like this:

[davidchambers]

The diagram in the readme indicates the dependencies that exist between algebra in the specification. Your diagram suggests we should add new dependencies to the specification. Please explain why this would be beneficial.

[Ne4to777]

The diagram in the readme indicates the dependencies that exist between algebra in the specification

No, it is not.

1. А Functor does not exist on its own. It can only be covariant or contravariant. Therefore, the Functor and Contravariant are entities of different order.
2. Profunctor must implements both Covariant and Contravariant at the same time

[CrossEye]

@Ne4to777:

You realize that this is open source, right? You're free to fork it and change your fork as you will, or to create your own. You are also free to create your own specification from scratch. If you feel strongly about it, you can then try to convince all those implementing these specs that your own are better and that they should switch.

While you're at it, you should probably edit the Wikipedia page on Functors to match your definition and convince the maintainers of languages such as Haskell, Scala, and Clojure to change their specifications to match.

Alternatively, you can simply stop trolling.

[puffnfresh]

The Fantasy Land Functor is short for "Covariant Functor"

Profunctor is super useful and I don't think it's specified, that's the only difference to the diagram that I can see.

[davidchambers]

Profunctor is super useful and I don't think it's specified, that's the only difference to the diagram that I can see.

Actually, Profunctor is specified. 🎉

Profunctor must implements both Covariant and Contravariant at the same time

Profunctor currently requires Functor but not Contravariant.

@Ne4to777, please explain why Profunctor should require Contravariant in addition to Functor. We will certainly consider changing the specification if presented with a compelling reason to do so. :)

[Ne4to777]

Alternatively, you can simply stop trolling.

@CrossEye ,
Who else is trolling?)

• Situation: There are 14 competing standards
• fourteen? Absurd! We need to develop one universal standard for all occasions!
• Situation: There are 15 competing standards

[Ne4to777]

The Fantasy Land Functor is short for "Covariant Functor"

This is the question why the derivatives of a covariant functor cannot be derivatives of a contravariant functor? For example contravariant monads.

Profunctor is super useful and I don't think it's specified, that's the only difference to the diagram that I can see.

and it implements the contravariant functor with the second argument

[Ne4to777]

@Ne4to777, please explain why Profunctor should require Contravariant in addition to Functor. We will certainly consider changing the specification if presented with a compelling reason to do so. :)

because:

1. nothing prevents derivatives (like Chain or Monad) from being used together with a contravariant functor
2. The profunctor implements a contravariant functor as its second argument

[davidchambers]

I have updated this issue's title to reflect the change @Ne4to777 is proposing.

@fantasyland/core, what do you think of the proposal?

[Ne4to777]

@davidchambers , aliasing Covariant to Functor is a bad idea too. Especially since we already have an abstract entity - a monad