# hello.ludic — smallest program that exercises the ECS pipeline
program Hello {

  property Pos { x: int = 0, y: int = 0 }
  property Vel { dx: int = 0, dy: int = 0 }

  handler Boot phase Start {
    spawn Mob {
      Pos { x: 3, y: 4 }
      Vel { dx: 1, dy: 0 }
    }
    spawn Mob {
      Pos { x: 10, y: 2 }
      Vel { dx: 0, dy: 1 }
    }
  }

  # a handler declares the entities it operates on with @Queries: the body then
  # runs once per match, each property bound by name and self() giving that entity.
  @Queries(these: [Pos, Vel])
  handler Move phase FixedUpdate {
    Pos.x += Vel.dx
    Pos.y += Vel.dy
  }

  handler Report phase Update {
    for (p) in query [Pos] {
      print(p.x)
      print(p.y)
    }
    quit()
  }
}