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
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 * -> *
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)
}
}