use vlib::Console;

Set<Entity> tickables
f64 lastTick

interface Tickable {
  handle tick(f64 dTime)
}

handle start() {
  defer(tick)
}

handle added(Tickable e) {
  tickables.add(e)
}

handle removed(Tickable e) {
  tickables.remove(e)
}

handle internal tick() {
  f64 time = $Time.sinceStart()
  f64 dTime = time - lastTick
  for(Tickable t : tickables) {
    t.tick()
  }
  lastTick = time
  defer(tick)
}