1 files changed, 17 insertions, 0 deletions
diff --git a/lib/kernel/rite.mli b/lib/kernel/rite.mli
index b9d1961..d53e4e6 100644
--- a/lib/kernel/rite.mli
+++ b/lib/kernel/rite.mli
@@ -140,4 +140,21 @@ type ('s, 'r) t = {
           parameters and the same reasons for each, a [bool] not an
           [option], and [false] is the answer a rite that has not
           implemented the rule returns explicitly. *)
+  preface : temporal:('s, 'r) Temporal.t -> observed:'r Celebration.t -> date:Date.t -> Preface.t option;
+      (** Which preface is said at this day's Mass (EF: RG 482-499). Same
+          seam and same three parameters as {!creed}/{!gloria}, for the
+          same reasons -- {!Preface}'s own citation has the rubric in full.
+          [Preface.t option], not a bare [Preface.t]: unlike [creed]/
+          [gloria], where "not said" is itself a legitimate answer a
+          [bool] can carry, a preface is said only at a MASS, and this
+          engine constructs at least one day (Good Friday, the
+          1955-restored Holy Week) that resolves an [observed] celebration
+          but has no Mass at all -- [None] is the honest answer there, not
+          a manufactured preface. [None] is also the value a rite that has
+          not implemented this rule returns, the same "the type's own
+          neutral value" contract {!creed}/{!gloria} give for [false] --
+          the two meanings ("this rite does not model the question" and
+          "this specific day has no Mass to preface") collapse onto the
+          same representation deliberately: a caller with no rite-specific
+          context to distinguish them should not need one. *)
 }