recur.scala

object qwe extends App {
  def str = {
    def find[A](s: Stream[A])(p: A => Boolean): Option[A] = {
      s.headOption match {
        case Some(x) if p(x) => Some(x)
        case None => None
        case _ => find(s.tail)(p)
      }
    }
//    Stream.iterate(1)(_ + 1).find(str => false).get
    find(Stream.iterate(1)(_ + 1))(_ => false)
  }

  str
}

stl.scala

object qwe extends App {
  def str = {
    def find[A](s: Stream[A])(p: A => Boolean): Option[A] = {
      var these = s
      while (!these.isEmpty) {
        if (p(these.head)) return Some(these.head)
        these = these.tail
      }
      None
    }
//    Stream.iterate(1)(_ + 1).find(str => false).get
    find(Stream.iterate(1)(_ + 1))(_ => false)
  }

  str
}