collections - Scala pattern matching on sequences other than Lists

Question

I have the following code which recursively operates on each element within a List

def doMatch(list: List[Int]): Unit = list match {
  case last :: Nil  => println("Final element.")
  case head :: tail => println("Recursing..."); doMatch(tail)
}

Now, ignoring that this functionality is available through filter() and foreach(), this works just fine. However, if I try to change it to accept any Seq[Int], I run into problems:

• Seq doesn't have ::, but it does have +:, which as I understand is basically the same thing. If I try to match on head +: tail however, the compiler complains 'error: not found: value +:'
• Nil is specific to List, and I'm not sure what to replace it with. I'm going to try Seq() if I ever get past the previous problem

Here is how I think the code should look, except it doesn't work:

def doMatch(seq: Seq[Int]): Unit = seq match {
  case last +: Seq() => println("Final element.")
  case head +: tail  => println("Recursing..."); doMatch(tail)
}

Edit: So many good answers! I'm accepting agilesteel's answer as his was the first that noted that :: isn't an operator in my example, but a case class and hence the difference.

Answer 1

As of the ides of March 2012, this works in 2.10+:

  def doMatch(seq: Seq[Int]): Unit = seq match {
    case last +: Seq() => println("Final element.")
    case head +: tail  => println("Recursing..."); doMatch(tail)
  }                                               //> doMatch: (seq: Seq[Int])Unit

  doMatch(List(1, 2))                             //> Recursing...
                                                  //| Final element.

More generally, two different head/tail and init/last decomposition objects mirroring append/prepend were added for Seq in SeqExtractors:

List(1, 2) match { case init :+ last => last } //> res0: Int = 2                                              
List(1, 2) match { case head +: tail => tail } //> res1: List[Int] = List(2)                                               
Vector(1, 2) match { case init :+ last => last } //> res2: Int = 2                                              
Vector(1, 2) match { case head +: tail => tail } //> res3: scala.collection.immutable.Vector[Int] = Vector(2)