I thought that a while ago I had read about Scala using "special" implementations when creating collections for a small amount of elements. E.g. for a List with only 4 elements, there is something like a "List4" that can carry exactly 4 elements, means that the implementation uses a fixed amount of fields (similar to the way tuples work, there are Tuple1, Tuple2, Tuple3 ...).
1.) Unfortunately, I can't find this information anymore. Am I wrong about what I just claimed above (perhaps I mixed it up with another language)?
2.) The reason for my question: in Scala, I often catch myself using collections for the simplest things. E.g. when checking a small amount of variables for their values, I often do something like this:
def checkCoordinates(x: Int, y: Int, z: Int) = Seq(x, y, z).forall(_ >= 0)
In Java, I never would have done that. That's mainly because collections in Scala (and in functional languages in general) feel much more lightweight, at least regarding the syntax. But what about the performance standpoint and the habit of using collections for simple tasks (such as shown above)?
