Scala foreach return

Question

How do you make this method work?

def filled(b: Board): Board = {
  b.next foreach { n =>
    if (n.filled) n
    else filled(n)
  }
}

I need it to return after first filled n (n.filled == true) like in Java.

Now I get:

chess-knight.scala:72: error: type mismatch;
 found   : Unit
 required: this.Board
    b.next foreach { n =>
           ^
one error found

Thanks!

Answer 1

Isn't this what you need?

def filled(b: Board): Board = b.next find {_.filled} get

Providing that b.next is a Seq[Board] and there is always at least one filled Board .

If you insist on purely functional prefer an approach exploiting pattern matching over List :

def filled(b: Board): Board = {
  b.next match {
    case n :: _ if(n.filled) => n
    case _ :: rest => filled(rest)
    case Nil => throw NoSuchElementException
}