Kaba class World ed

class World
    var background: color
    var ego: Entity*
    var fog: Fog
    var gravity: vec3
    var links: Link&[]
    var msg_data: MessageData
    var physics_mode: PhysicsMode
    var skyboxes: Model&[]

    # constructors
    func mut __init__()

    # functions
    func mut selfref add_particle(p: xfer[LegacyParticle]) -> LegacyParticle&
    func mut selfref add_sound(s: xfer[Sound])
    func mut selfref attach_model(e: Entity&, filename: Path) -> Model&
    func mut selfref create_camera(pos: vec3, ang: quaternion) -> Camera&
    func mut selfref create_entity(pos: vec3, ang: quaternion) -> Entity&
    func mut selfref create_light_cone(pos: vec3, ang: quaternion, c: color, radius: f32, theta: f32) -> Light&
    func mut selfref create_light_parallel(ang: quaternion, c: color) -> Light&
    func mut selfref create_light_point(pos: vec3, c: color, radius: f32) -> Light&
    func mut selfref create_object(filename: Path, pos: vec3, ang: quaternion) -> Entity&
    func mut selfref create_object_multi(filename: Path, pos: vec3[], ang: quaternion[]) -> Entity&
    func mut selfref create_object_no_reg(filename: Path, pos: vec3, ang: quaternion) -> Entity&
    func mut selfref create_terrain(filename: Path, pos: vec3) -> Terrain&
    func delete_entity(e: Entity*)
    func delete_link(e: Link*)
    func delete_particle(e: LegacyParticle*)
    func delete_sound(e: Sound*)
    func get_g(pos: vec3) -> vec3
    func selfref lights() -> Light&[]&
    func mut load_soon(filename: Path)
    func selfref objects() -> Model&[]&
    func mut register_entity(e: Entity*)
    func mut set_active_physics(o: Model, active: bool)
    func mut shift_all(dpos: vec3)
    func mut subscribe(msg: string, f: void->void)
    func selfref terrains() -> Terrain&[]&
    func trace(p1: vec3, p2: vec3, out d: CollisionData, simple_test: bool, ignore: Entity*) -> bool
    func mut selfref unattach_model(m: Model&)

    # nested classes
    class MessageData
    class PhysicsMode