(** Whether this celebration can be the observed day at all. The 1960 reform
    reduced many feasts to a bare commemoration; they retain a rank but can
    never be observed. NOT a fifth rank: RG 8 fixes the classes at four.

    What the retained rank is FOR (corrected 2026-08-12): this line formerly
    read "RG 111 orders admitted commemorations by dignity". Ordering is no
    longer done by rank at all -- it moved to the rite's own table of
    precedence (RG 113) in commit ea22ad2, and a bare commemoration has no
    row in that table. The rank remains load-bearing for ADMISSION: RG 111(b)
    reserves a II-class Sunday's single slot "de festo II classis", a floor
    read off this rank directly. *)
type status = Feast | Commemoration_only [@@deriving sexp]

(** A celebration. Parameterised by the rite's rank type only. *)
type 'r t = {
  slug : Slug.t;
  names : Names.t;
  rank : 'r;
  status : status;
  colour : Colour.t;
  subject : Subject.t;
  citations : Citation.t list;
  layer : string;
}
[@@deriving sexp]

(** [status] defaults to [Feast], [subject] to [Subject.Temporal], [names] to
    empty, [citations] to []. *)
val make :
  slug:Slug.t -> ?names:Names.t -> rank:'r -> ?status:status -> colour:Colour.t ->
  ?subject:Subject.t -> ?citations:Citation.t list -> layer:string -> unit -> 'r t