https://github.com/christopherdavenport/rank3

https://github.com/christopherdavenport/rank3

Last synced: 13 days ago
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• Host: GitHub
• URL: https://github.com/christopherdavenport/rank3
• Owner: ChristopherDavenport
• Created: 2018-11-01T23:42:31.000Z (about 6 years ago)
• Default Branch: master
• Last Pushed: 2022-05-24T22:19:26.000Z (over 2 years ago)
• Last Synced: 2024-10-24T08:50:37.653Z (22 days ago)
• Language: Scala
• Size: 161 KB
• Stars: 7
• Watchers: 3
• Forks: 2
• Open Issues: 33
• Metadata Files:
  • Readme: README.md

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README

        
# rank3 [![Build Status](https://travis-ci.com/ChristopherDavenport/rank3.svg?branch=master)](https://travis-ci.com/ChristopherDavenport/rank3)

A set of algebras exposing operations for rank3 transformations. Such that the expression operates on

`F[_[_]]` and forall `H[_]`.

To this end we currently expose 4 sets of rank3 constructs

```scala

trait Function1R3[F[_[_]], G[_[_]]]{

  def apply[H[_]](a: F[H]): G[H]

}

type ~~> = Function1R3

EitherR3[F[_[_]], G[_[_]], H[_]] = Either[F[H], G[H]]

IorR3[F[_[_]], G[_[_]], H[_]] = Ior[F[H], G[H]]

Tuple2R3[F[_[_]], G[_[_]], H[_]] = (F[H], G[H])

```

Each of the algebras can be mixed to build arbitrary composition over rank3 values `forall * -> *`

## Example

```scala

trait Foo[F[_]]{

  def foo: F[Int]

}

trait Bar[F[_]]{

  def bar: F[Int]

}

val transform = new ~~>[Tuple2R3[Functor, Foo, ?[_]], Bar] {

  def apply[F[_]](fh: Tuple2R3[Functor, Foo, F]): Bar[F] = new Bar[F]{

    def bar = fh.fst.map(fh.snd.foo)(_ + 1)

  }

}

```