Various ways to recurse down Exception causes in Scala

ExceptionDig.scala

 // Using vars, lots of local mutation
def getThemVar(th:Throwable)={
  var now=th
  var li=List[Throwable](now)  
  var cause=now.getCause
  while (cause!=null){
    li=cause::li
    now=cause
    cause=now.getCause
  }
  li.reverse.toVector
}

 // Using recursion and tailrec so as not to blow the stack
def getThemTailRec(th:Throwable)={
  @scala.annotation.tailrec
    def inner(th:Throwable,v:Vector[Throwable]):Vector[Throwable]={       
      val tail=v:+th
      if (th.getCause==null) tail else inner(th.getCause,tail)       
    }
    inner(th,Vector[Throwable]())
  }

 // simple recursion, might blow stack if exception VERY deep
def getThemSimpleRecurse(th:Throwable):Vector[Throwable]=    
    Vector[Throwable](th) ++ (if (th.getCause==null) Nil else getThemSimpleRecurse(th.getCause) 
 
 // Using the power of Iterator.iterate, will give you iterator of ha and all causes    
def getIterate(ha:Throwable)=
 Iterator.iterate(ha)(_.getCause).takeWhile(_!=null).toVector    
    
val ha:Throwable=new Exception(new Throwable("I have gone bang",new Exception("I am the cause")))

// All emit
// Vector(java.lang.Exception: java.lang.Throwable: I have gone bang, java.lang.Throwable: I have gone bang, java.lang.Exception: I am the cause)