merge: celebrant Mass rubrics, and four rubrical corrections

colitur now prints what a real ordo prints for the Mass: which formulary is
said and how it was reached, the Gloria, the Creed, the preface, and the
commemorations with their Low-Mass/sung distinction. colitur rubrics joins
day and readings.

Four defects were found and fixed on the way, each by an external witness
rather than by inspection: the Creed said at Requiem Masses (RG 476(f)),
the missing bissextile shift of St Matthias and St Gabriel (2 041 leap
years), Rogation Monday and Tuesday coloured violet in Paschaltide (RG
119(b)), and the ferias after the Ascension resuming the wrong Sunday's
Mass rather than the Ascension's.

Validation gained a sixth layer and then some: the preface is checked
against three independent publishers over seven witness-years (FIUV, three
LMS editions, three extraordinaryform.org editions), none of which shares
the Divinum Officium -> missalemeum -> lectio lineage the older layers all
descend from.

1 files changed, 14 insertions, 0 deletions

diff --git a/lib/kernel/precedence.ml b/lib/kernel/precedence.ml
index c207117..7138b6a 100644
--- a/lib/kernel/precedence.ml
+++ b/lib/kernel/precedence.ml
@@ -91,3 +91,17 @@ let resolve rules ctx ~temporal ~sanctoral =
       List.rev omitted
       @ List.map (fun (c, _) -> (c, "omitted: admission limit reached")) dropped;
   }
+
+(* RG 111(a): at most one commemoration, and it must be privileged -- see
+   the .mli for the full citation and why this is a derivation over the
+   admitted Low-Mass list rather than a second admission rule. [List.find_opt]
+   keeps input order, which is already precedence order (RG 113), so "the
+   first privileged entry, if any" is "the highest-precedence privileged
+   entry, if any" -- the correct single survivor if more than one privileged
+   commemoration were ever admitted together (not known to occur on any
+   shipped rite's data, but not assumed impossible either: this reads the
+   list rather than asserting its length). *)
+let sung_mass_commemorations low_mass_set =
+  match List.find_opt (fun (_, p) -> p = Privileged) low_mass_set with
+  | Some c -> [ c ]
+  | None -> []