stream-lazy-foldRight.scala

def fold[S,A](seed: =>S)(f:(Function0[S],A)=>S,stream:Stream[A]):S={
  stream match{
    case Stream.#::(x,xs) => f(()=>(fold[S,A](seed)(f,xs)),x)
    case Stream.Empty =>seed}
}

fold[Stream[Int],Int](Stream.Empty)((s,a)=>Stream.cons(a,s()),Stream.fill(10000)({println("oooo ");10000}))

outputs

oooo 
res3: Stream[Int] = Stream(10000, ?)

Of course the implementation is terribly slow and leaks space!