Group consecutive siblings according to truth/falsity. Useful to interpret something like parsing output from the shell to distinguish between Input and Output.

groupSiblings.scala

def continuousPartitions[A](l: List[A])(f: A => Boolean): List[(List[A], List[A])] = {
  if ( l.isEmpty ) Nil
  else {
    val (continuousTrue, followingPartition) = l span f
    val (continuousFalse, nextGroup) = followingPartition span (!f(_))
    (continuousTrue, continuousFalse) :: continuousPartitions(nextGroup)(f)
  }
}

val hav = continuousPartitions(List("a", "b", "a", "a", "b", "b", "a"))(_=="a")

val exp = List(
  (List("a"),List("b")),
  (List("a","a"),List("b","b")),
  (List("a"), Nil)
)

println(hav)
println(exp)


assert(hav == exp, "Check that the lists are identical.")
assert(Nil == continuousPartitions(List())(_ => true), "Empty input should return empty result.")