kernel(celebration): distinguish a feast from a commemoration-only entry

The 1960 reform reduced many feasts to a bare commemoration. They keep a rank,
because RG 111 orders admitted commemorations by dignity, but they can never be
the observed day. Modelled as a separate status rather than a fifth rank: RG 8
fixes the classes at four.

1 files changed, 10 insertions, 2 deletions

diff --git a/lib/kernel/celebration.mli b/lib/kernel/celebration.mli
index 1c84d35..a3c2960 100644
--- a/lib/kernel/celebration.mli
+++ b/lib/kernel/celebration.mli
@@ -1,8 +1,15 @@
+(** Whether this celebration can be the observed day at all. The 1960 reform
+    reduced many feasts to a bare commemoration; they retain a rank (RG 111
+    orders admitted commemorations by dignity) but can never be observed. NOT
+    a fifth rank: RG 8 fixes the classes at four. *)
+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;
@@ -10,7 +17,8 @@ type 'r t = {
 }
 [@@deriving sexp]
 
-(** [subject] defaults to [Subject.Temporal], [names] to empty, [citations] to []. *)
+(** [status] defaults to [Feast], [subject] to [Subject.Temporal], [names] to
+    empty, [citations] to []. *)
 val make :
-  slug:Slug.t -> ?names:Names.t -> rank:'r -> colour:Colour.t ->
+  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