val ls = List(0, -1, 2, -2)
var removeNegative = List[Int]()
def removeNegative(ls: List[Int]): Int = ls match {


  case Nil => 0
  case l::for(ls <- ls){
    var removeNegative = List[Int]()
        if(ls >= 0){
                removeNegative = removeNegative :+ ls
        }
    }


    return removeNegative
}


println(removeNegative(ls)

ScalaFiddle.scala:7: error: illegal start of simple pattern
    case l::for(ls <- ls){
            ^
ScalaFiddle.scala:16: error: '=>' expected but '}' found.
  }
  ^