From 12b97761019cfa02ca0da8a5fb50ef815d07685c Mon Sep 17 00:00:00 2001 From: Lukasz Kasprzak Date: Fri, 21 Aug 2026 14:42:30 +0200 Subject: feat(ef): implement RG 33's third omission trigger RG 33 omits a II/III-class vigil in three cases: it falls on a Sunday, it falls on a I-class feast, "vel si festum cui praemittitur in alium diem transferri aut ad commemorationem reduci contingat". Only the first two were built; the third was recorded in precedence_ef.ml as unimplemented on the grounds that no witness existed in the shipped data. That reasoning was wrong, and the rule fires on 1 744 days across 1583-9999. Both halves of the clause reduce to one observable question -- is the feast the OBSERVED office on the following day (RG 34 puts it there) -- so the kernel asks it once per candidate, after place_transfers has settled the year. No fixed point is needed: a vigil is a candidate only on its own day, never on its feast's, so suppressing it cannot change what the next day observes. Precedence.rules gains vigil_feast, which returns the slug of the feast a vigil precedes; the kernel cannot infer that itself, because only two of the five vigil/feast pairs share a slug stem. Blast radius, measured pre-change binary vs HEAD over the whole domain and classified: 1 744 days, three shapes, zero unexplained. 1 199 are the feast reduced to a commemoration (10 August on a Sunday, St Lawrence); 478 and 67 are the feast transferred under RG 96 after the Sacred Heart or Corpus Christi takes its day. The Assumption's and the Ascension's vigils never qualify -- their I-class feasts always keep their own day. Independently witnessed, which is unusual here. The published Ordo -- the only witness outside the Divinum Officium -> missalemeum -> lectio lineage -- omits St Lawrence's vigil on 2025-08-09, agreeing with colitur against both engines. That date had been read earlier as an Ordo gap; the Ordo was right, and correcting the misreading is what surfaced this clause. On 2027-08-09 the feast does keep its day and the Ordo omits a vigil colitur correctly keeps, which is a genuine Ordo gap. Allow-lists: C39 (lectio, 10 rows) and a 2038 oracle class citing the register, the 2026-2027 window having no instance. The golden pin asserting St Lawrence's vigil is violet moved 2025 -> 2027; its own comment had reasoned about the vigil's weekday and missed that RG 33 also looks at the feast's. Two new pins cover both shapes of the clause. The vigil/feast table is built with Slug.of_string_exn: mutation testing showed that of_string plus Result.to_option turns a typo into None, which this hook's contract reads as "not a vigil", switching the rule off in silence. Two tests assert the table against the shipped data in both directions. --- lib/rites/rite_ef/precedence_ef.ml | 55 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) (limited to 'lib/rites/rite_ef/precedence_ef.ml') diff --git a/lib/rites/rite_ef/precedence_ef.ml b/lib/rites/rite_ef/precedence_ef.ml index b69ee52..36aea83 100644 --- a/lib/rites/rite_ef/precedence_ef.ml +++ b/lib/rites/rite_ef/precedence_ef.ml @@ -600,6 +600,61 @@ let is_bvm_office (c : Vocab_ef.rank Precedence.candidate) = (ยง6) rather than guessed. *) let is_omissible_vigil (rank : Vocab_ef.rank) = rank = Vocab_ef.Class2 || rank = Vocab_ef.Class3 +(* RG 33's THIRD omission trigger, the clause [is_omissible_vigil]'s own + comment above records as unimplemented: "vel si festum cui praemittitur in + alium diem transferri aut ad commemorationem reduci contingat" -- "or if + the feast it precedes happens to be transferred to another day or reduced + to a commemoration". + + Each pair is (vigil slug, the slug of the feast it precedes). RG 34 fixes + the feast on the day AFTER the vigil ("Vigiliae... celebrantur die + praecedenti festum"), so the kernel needs no date here, only the identity + -- and it must be given the identity rather than deriving it, because + these slugs do not derive from one another: two of the five share a stem + with their feast and three do not (see {!Precedence.rules.vigil_feast}). + + The five are exhaustive for the 1962 universal calendar. The four + sanctoral ones are the only entries in data/ef/sanctoral.sexp matching + [is_vigil]; the fifth is temporal_ef's own Ascension vigil. The two + I-class vigils (Nativity Eve, Pentecost Vigil) are deliberately ABSENT: + RG 33 governs only "Vigilia II aut III classis", and RG 30 puts a I-class + vigil beyond losing in the first place -- the same argument + [is_omissible_vigil] already makes for the other two triggers. + + A user overlay adding a diocesan vigil is NOT covered by this table and + its vigil will not be omitted. That is a data limit, not an architectural + one -- the kernel hook takes any candidate -- and it is stated here rather + than papered over with a slug-shape heuristic that would be wrong for + three of the five universal cases it can already be checked against. *) +(* Built with [Slug.of_string_exn], deliberately, and at module initialisation + rather than per call. A malformed literal here is a PROGRAMMING error in a + static table, not untrusted input, and the alternative found by mutation + testing is worse than a crash: with [Slug.of_string] and [Result.to_option] + a typo (an uppercase letter is enough -- slugs are lowercase-only) collapses + to [None], which this function's own contract reads as "not a vigil", and + the whole rule switches itself off for that entry in silence. That failure + was reproduced: mutating "lawrence" to "lawrence-WRONG" reddened FOUR tests, + all of them the ones that notice the rule missing, and none that notice it + pointing at the wrong feast -- indistinguishable from deleting the row. + The same mutation with a well-formed "lawrence-wrong" reddens eighteen. + Raising at startup keeps a typo loud; [Rite_ef]'s own bundle is constructed + at initialisation too, so the failure surfaces before any calendar is + resolved. *) +let vigil_feast_table = + List.map + (fun (vigil, feast) -> (vigil, Slug.of_string_exn feast)) + [ ("ef-ascension-vigil", "ef-ascension"); + ("vigil-of-the-nativity-of-st-john-the-baptist", "nativity-of-st-john-the-baptist"); + ("vigil-of-sts-peter-paul", "sts-peter-paul"); + ("vigil-of-st-lawrence", "lawrence"); + ("vigil-of-the-assumption", "assumption-of-the-blessed-virgin-mary") ] + +let vigil_feast (c : Vocab_ef.rank Precedence.candidate) : Slug.t option = + let cel = c.Precedence.cel in + if not (is_omissible_vigil cel.Celebration.rank) then None + else List.assoc_opt (Slug.to_string cel.Celebration.slug) vigil_feast_table + + (* Every Sunday slug this rite's temporal cycle produces -- named (temporal_ef.ml's [named], e.g. "ef-easter-sunday") or the generic "ef--sunday-" fallback ([sunday_slug]) -- contains this -- cgit v1.3