ocaml/testlabl/bugs/pr4018.ml

47 lines
1.0 KiB
OCaml

class virtual ['subject, 'event] observer =
object
method virtual notify : 'subject -> 'event -> unit
end
class ['event] subject =
object (self : 'subject)
val mutable observers = ([]: (('subject, 'event) observer) list)
method add_observer obs = observers <- (obs :: observers)
method notify_observers (e : 'event) =
List.iter (fun x -> x#notify self e) observers
end
type id = int
class entity (id : id) =
object
val ent_destroy_subject = new subject
method destroy_subject : (id) subject = ent_destroy_subject
method entity_id = id
end
class ['entity] entity_container =
object (self)
inherit ['entity, id] observer as observer
method add_entity (e : 'entity) =
e#destroy_subject#add_observer (self)
method notify _ id = ()
end
let f (x : entity entity_container) = ()
(*
class world =
object
val entity_container : entity entity_container = new entity_container
method add_entity (s : entity) =
entity_container#add_entity (s :> entity)
end
*)