replace.scala

trait Replaceable[A] {
  def replace[A, B](src: A)(in: A, out: B): B
}

trait StringExample extends Replaceable[String] {
  def replace(src: String)(in: String, out: String): String = {
    src.replace(in, out)
  }
}

trait ListExample[A, B] extends Replaceable[List[A]] {

  private def replacer(x: A, y: B) = (i: A) => if (i == x) y else i

  def replace(src: List[A])(in: A, out: B): List[B] = {
    src map(item => replacer(in, out)(item))
  }
}

trait FutureExample[A, B] extends Replaceable[Future[A]] {

  private def replacer(x: A, y: B) = (i: A) => if (i == x) y else i

  def replace(src: Future[A])(in: A, out: B): List[B] = {
    src map(item => replacer(in, out)(item))
  }
}