# the smallest program that exercises the whole ECS pipeline
program Hello {

  property Position { column: int = 0, row: int = 0 }
  property Velocity { delta_x: int = 0, delta_y: int = 0 }

  handler SpawnEnemies phase Start {
    spawn Enemy { Position { column: 3, row: 4 },   Velocity { delta_x: 1, delta_y: 0 } }
    spawn Enemy { Position { column: 10, row: 2 },  Velocity { delta_x: 0, delta_y: 1 } }
  }

  # a handler declares the entities it touches; the body
  # runs once per match, each property bound by name.
  @Queries(these: [Position, Velocity])
  handler AdvancePositions phase FixedUpdate {
    Position.column += Velocity.delta_x
    Position.row    = Position.row + Velocity.delta_y
  }

  handler ReportPositions phase Update {
    for (moving) in query [Position] {
      print(moving.column)
      print(moving.row)
    }
    quit()
  }
}