Run/Debug Config on IDEA 13 for Scala Application - scala

Question

complete stranger/newbie question, sorry to bother you:
I want to run a scala project in IDEA 13 (on Mac OSX), there is no run/debug configuration. I tried some options, however I don't know what to choose (and what should happen, then).
I tried:
Scala Console
Scala Script
Scala Test
Specs2
Choosing Scala Console: something happens, but I get no message box from my showMessage(message = "Hello World") messagebox. (It did work in Eclipse, so far).
Scala Script: I suppose this is meant for single lines of code, not an app, is that?
Specs2: Error in options-dialog: Specs2 is not specified. What is spec2? What should I enter and where? Error while debugging: no main class detected. OK, there is none, I can see that.
Any other option I should use, or normally is used?
Would any help appreciate very much!
This is my (very simple) scala app. Somehow, I'd expect to get an message box while running from IDEA.
import swing._
import swing.Dialog._
import scala.swing.event.ButtonClicked
object HW {
def main(args: Array[String]): Unit = {}
showMessage(message = "Hello World")
}
by the way: the closest tread I've found was this, but it didn't really help, looked too different:
How to run scala code on Intellij Idea 11?

Answer 1

Just use "Application". You have to select a main class and a module.
In terms of your example, I recommend not mixing a def main with a "free" standing constructor body. Also, Swing code should be called only from the event dispatch thread (Swing.onEDT). The easiest for desktop applications is to extend trait SwingApplication which handles that for you:
import swing._
import swing.Dialog._
object HW extends SwingApplication {
def startup(args: Array[String]): Unit =
showMessage(message = "Hello World")
}