gistfile1.scala

trait Action {

  // ...
  def instantiate(inventory: ResourceMap[Resource], units: Iterable[Unit]):ActionMachine


}

class BuildAction(tpe: UnitType) extends AwesomeAction {
  def instantiate(inventory: ResourceMap[Resource], units: Iterable[Unit]):ActionMachine = new ActionMachine {
    val builder = units.head

    // register failure handler
    val failHandle = on(builder.death) { event => fail()}

    var position = findBuildSpot(...)

    
    self.loop(frame) until (builder.closeTo(position) | failure) { frame =>
      if(!builder.canBuildHere(position,tpe)) {
          position = findBuildSpot(...)
      }
    }

    // suspend until building started, return new building
    builder.startBuilding(position,tpe) match {
      Some(building) =>
      None => fail()
    }

    // register completion and failure handlers
    on(newBuilding.complete) { event => succeed() }
    on(newBuilding.death) { event => fail() }
    
  }

  val failure = new EventSource[Fail[MoveAction]]
  val success = new EventSource[Success[MoveAction]]
}