Traverse instance for Eff

[edmundnoble]

I think we should be able to provide a Traverse instance for Eff[S, A], given that all of the members of S have Traverse instances; by this I mean that all of them are possible to run without detach.

[etorreborre]

How would you write the type signature?

implicit def effTraverse[R : TraverseFx]: Traverse[Eff[R, ?]] = new Traverse[Eff[R, ?]] {
  def traverse[G[_]: Applicative, A, B](fa: Eff[R, A])(f: A => G[B]): G[Eff[R, B]] = ???
}

/**
 * can we get the Traverse instances for individual effects like that?
 */
trait TraverseFx[R <: Fx] {
  type H[_] <: Fx
  type T <: Fx

  def traverse: Traverse[H]
  def traverseFx: TraverseFx[T]
}

[etorreborre]

I'm closing this for now, please re-open if there is some interest again.