type 'a cell = | Nil| Cons of {content : 'a;mutable next : 'a cell;
}
type 'a t = {mutable length : int;mutable first : 'a cell;mutable last : 'a cell;
}val of_abstr : 'a Stdlib.Queue.t -> 'a tval to_abstr : 'a t -> 'a Stdlib.Queue.tval filter_inplace : ('a -> bool) -> 'a t -> unit