prof.scala

import scalaz._
import Scalaz._

object IsItAProfunctor extends App {

  case class Foo(f: Double)

  val validateDouble: Double ⇒ Validation[String,Double] = {d ⇒
    if(d < 0) "less than zero".fail
    else d.success
  }

  val validateFoo: Foo ⇒ Validation[String,Foo] = validateDouble.dimap((_:Foo).f, _.map(Foo))

  assert(validateFoo(Foo(1D)) == Foo(1D).success)
  assert(validateFoo(Foo(-1D)) == "less than zero".fail)
}