feat(ef): the Creed, RG 475-476

Whether the Creed is said at Mass. New Rubrics_ef.creed, reached through
a new Rite.t.creed field and a new Liturgical_day.t.creed bool (false,
not an option, for a rite that has not implemented the rule); colitur
rubrics gains a fourth TAB-separated column.

475(a) reads the TEMPORAL cycle's own weekday, not the observed day: a
Sunday impeded by a Feast of the Lord (RG 16a) still says the Creed.
475(d)'s three octaves (Nativity, Easter, Pentecost) are pure date/
Easter-offset windows, checked first, since a saint's feast winning the
day inside one of them still says the Creed ("etiam in festis
occurrentibus") -- St Stephen, 26 December, is the live witness.

RG 23 classifies Ash Wednesday and every feria of Holy Week (including
the Sacred Triduum) as feriae, not festa, however high their rank, so
475(b)/(c)'s "in festis" never reaches them; this single check subsumes
476(a)'s own naming of the Chrism/Lord's-Supper Mass and the Easter
Vigil. RG 28-34 vigils are a third liturgical-day category, also
excluded from "in festis" regardless of rank -- reuses the already-
exported Precedence_ef.is_vigil rather than a new list.

475(e)'s Apostle/Evangelist natalicia list (creed_apostle_slugs) was
derived by grepping data/ef/sanctoral.sexp directly and checking each
candidate's own date against whether it is that saint's dies natalis --
not copied from any list supplied with the task. The Conversion of St
Paul and the 30 June Commemoration of St Paul are excluded (neither is
a natalicium); the Chair of St Peter and St Barnabas are included only
because the clause names them explicitly, which is exactly why it has
to: neither is a natalicium either.

475(c)'s BVM half reuses Precedence_ef.marian_slugs (newly exported)
rather than the subject field alone: checked against the shipped data,
almost every Marian sanctoral entry ships subject=Saint, not Bvm.

man/colitur.1's rubrics section is updated to match the new column;
test/cli.t repinned via dune promote for the same reason. Verified
day/readings output byte-identical to v0.10.1 across the whole
1583-9999 domain (both binaries' concatenated day+readings output,
6,148,492 lines each, zero diff). Domain-wide: 882,996 days say the
Creed, 2,191,250 do not; every one of the domain's 439,178 Sundays says
it, zero exceptions.

1 files changed, 223 insertions, 0 deletions

diff --git a/lib/rites/rite_ef/rubrics_ef.ml b/lib/rites/rite_ef/rubrics_ef.ml
new file mode 100644
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+(* RG 475-476 (docs/research/LT.txt, grep "dicitur symbolum"; scan1.txt line
+   ~3872-3888), quoted here in full so every branch below can cite its own
+   letter without re-quoting the whole rubric:
+
+     "475. Post Evangelium aut homiliam, dicitur symbolum:
+        a) in qualibet dominica, etsi eius Officium alicui festo locum
+     cedat, vel Missa votiva II classis celebretur;
+        b) in festis I classis et in Missis votivis I classis;
+        c) in festis II classis Domini et B. Mariae Virg.;
+        d) per octavas Nativitatis Domini, Paschatis et Pentecostes, etiam
+     in festis occurrentibus et in Missis votivis;
+        e) in festis nataliciis Apostolorum et Evangelistarum, necnon in
+     festis Cathedrae S. Petri et S. Barnabae Ap.
+
+     476. Non dicitur symbolum:
+        a) in Missis sive chrismatis sive in Cena Domini, feria V
+     Hebdomadae sanctae, et in Missa Vigiliae paschalis;
+        b) in festis II classis, iis exceptis quae supra, n. 475 c et e,
+     recensentur;
+        c) in Missis votivis II classis;
+        d) in Missis festivis et votivis III et IV classis;
+        e) ratione alicuius commemorationis in Missa occurrentis;
+        f) in Missis defunctorum."
+
+   SCOPE NOTE, checked once here rather than at every clause below: this
+   engine resolves ONE observed office and ONE Mass per civil day (see
+   Rite.t.readings' own doc comment) -- it has no separate "which votive
+   Mass is said" dimension. So the "vel/et...votivis" halves of 475(a)/(b),
+   476(c) entirely, 476(d)'s "et votivis" half, and 476(f) (Requiem Masses,
+   also not modelled) are genuinely inapplicable to this implementation --
+   a documented scope limit, not a defect. 476(e) needs no branch at all:
+   [creed] below reads only [observed], never a day's admitted
+   commemorations, so a commemoration can never change its answer by
+   construction. *)
+
+open Colitur_kernel
+
+(* RG 475(e): "in festis nataliciis Apostolorum et Evangelistarum, necnon in
+   festis Cathedrae S. Petri et S. Barnabae Ap." NATALICIUM means the feast
+   of the saint's own death (dies natalis) -- not every feast that merely
+   names him. That is precisely why the clause has to name the Chair of St
+   Peter and St Barnabas EXPLICITLY: neither is a natalicium (Peter's own is
+   29 June, shared with Paul; Barnabas's is his own day, 11 June, but the
+   clause names him anyway, redundantly with the natalicium reading, rather
+   than leave it to inference), so neither would be covered without the
+   explicit "necnon".
+
+   DERIVED, not copied from any list supplied with this task: grepped
+   data/ef/sanctoral.sexp directly for every entry whose English or Polish
+   name mentions "Apostle"/"Evangelist"/"Aposto{l/ł}a", then each
+   candidate's own date, rank and status checked against the calendarium
+   and against whether it is that saint's own dies natalis. Every entry
+   below was cross-checked against the shipped data, not assumed:
+
+     andrew (30 Nov, Class2) -- his natalicium.
+     barnabas (11 June, Class3) -- named explicitly; also his own natalicium.
+     bartholomew (24 Aug, Class2) -- his natalicium.
+     chair-of-st-peter (22 Feb, Class2) -- named explicitly ("Cathedrae S.
+       Petri"); NOT a natalicium (Peter's own is 29 June, shared with Paul)
+       -- exactly why the clause has to name it.
+     james-the-greater (25 July, Class2) -- his natalicium.
+     john-the-evangelist (27 Dec, Class2) -- his natalicium (the one Apostle
+       traditionally held to have died a natural death; "natalicium" still
+       names his own feast day, not only a martyr's).
+     luke-the-evangelist (18 Oct, Class2) -- his natalicium.
+     mark (25 April, Class2) -- the Evangelist ("Marka Ewangelisty" in the
+       data's own Polish name); NOT "mark-i" (7 Oct), a different saint (a
+       Pope), excluded.
+     matthew (21 Sep, Class2) -- Apostle and Evangelist, his natalicium.
+     matthias (24 Feb, Class2) -- his natalicium.
+     sts-peter-paul (29 June, Class1) -- the natalicium of both.
+     sts-philip-james (11 May, Class2) -- the natalicium of both (James the
+       Less; there is no separate "james-the-less" entry in the data).
+     sts-simon-jude (28 Oct, Class2) -- the natalicium of both.
+     thomas (21 Dec, Class2) -- his natalicium.
+
+   Checked and DELIBERATELY EXCLUDED (the Trap this clause is built around):
+     conversion-of-st-paul (25 Jan, Class3) -- not a natalicium: it
+       commemorates an EVENT of his life, not his death.
+     in-commemoratione-sancti-pauli-apostoli (30 June, Class3, status
+       Feast, so it CAN be observed, unlike the two entries below) -- a
+       secondary commemoration of Paul, not his dies natalis (his own is 29
+       June, with Peter); its own name says so ("In Commemoratione", not a
+       feast of his martyrdom).
+     "peter" (25 Jan) and "paul" (22 Feb) -- both status
+       [Commemoration_only] (RG 110's own Peter/Paul companions, on the
+       Conversion and Chair days respectively: {!Precedence_ef.disposition}'s
+       own citation), so neither can ever be [observed]; moot either way,
+       but neither is a natalicium regardless.
+     mark-i (7 Oct) -- a different saint (Pope St Mark), not the
+       Evangelist. *)
+let creed_apostle_slugs =
+  [ "andrew"; "barnabas"; "bartholomew"; "chair-of-st-peter"; "james-the-greater";
+    "john-the-evangelist"; "luke-the-evangelist"; "mark"; "matthew"; "matthias";
+    "sts-peter-paul"; "sts-philip-james"; "sts-simon-jude"; "thomas" ]
+
+let creed ~(temporal : (Vocab_ef.season, Vocab_ef.rank) Temporal.t)
+    ~(observed : Vocab_ef.rank Celebration.t) ~(date : Date.t) : bool =
+  let easter = Computus.gregorian_easter (Date.year date) in
+  let n = Date.to_rata date - Date.to_rata easter in
+  let m = Date.month date and dd = Date.day date in
+  let slug = Slug.to_string observed.Celebration.slug in
+  if
+    (* RG 475(d): "per octavas Nativitatis Domini, Paschatis et
+       Pentecostes, etiam in festis occurrentibus et in Missis votivis" --
+       an unconditional window override, checked first: EVEN a saint's
+       feast that wins the day within one of the three octaves (St Stephen,
+       26 December, is the live witness -- RG 67's own "Com. octavae
+       Nativitatis" note, quoted in full in temporal_ef.ml's [named]) still
+       says the Creed. Pure date/Easter-offset arithmetic, not season or
+       rank: Ascension (Easter+39) and the Pentecost Vigil (Easter+48) are
+       both [Class1] and both fall inside the Paschaltide SEASON but
+       outside either 8-day OCTAVE, so a rank- or season-based test here
+       would wrongly include them -- checked and rejected for exactly this
+       reason.
+
+       Nativity: 25-31 December (its own day plus 7) + 1 January (RG 91
+       entry 5's own "Octave Day of the Nativity", the identical table
+       entry as 24 December's vigil -- temporal_ef.ml's [named]). Easter:
+       Easter Sunday (offset 0) through Low Sunday (offset 7) -- RG 11's
+       own "dominicae Paschatis et Pentecostes sunt pariter festa I classis
+       CUM OCTAVA". Pentecost: Pentecost (offset 49) through Trinity Sunday
+       (offset 56), the RG 91-entry-14-adjacent "octave day" Trinity Sunday
+       itself names in temporal_ef.ml. *)
+    (m = 12 && dd >= 25 && dd <= 31)
+    || (m = 1 && dd = 1)
+    || (n >= 0 && n <= 7)
+    || (n >= 49 && n <= 56)
+  then true
+  else if
+    (* RG 475(a): "in qualibet dominica, ETSI EIUS OFFICIUM ALICUI FESTO
+       LOCUM CEDAT" -- the Creed is said on any Sunday even when a feast
+       displaces the Sunday's own office (RG 16(a): a Feast of the Lord I
+       or II class occurring on a II-class Sunday takes its place "cum
+       omnibus iuribus et privilegiis"). Read off [temporal]'s own weekday
+       -- the day's calendar fact, independent of whatever [observed] turns
+       out to be -- never off [observed]'s slug or rank, which is exactly
+       what would go silently wrong the day such an impeding feast wins:
+       see {!Colitur_kernel.Precedence.rules.admit}'s own [~temporal]
+       parameter (precedence.mli) for the identical argument, made there
+       for RG 111(b) rather than RG 475(a). *)
+    temporal.Temporal.weekday = Date.Sun
+  then true
+  else if
+    (* RG 23 (Caput IV, "De Feriis"): "Feriae I classis sunt: a) feria IV
+       cinerum; b) omnes feriae Hebdomadae sanctae." Ash Wednesday and every
+       feria of Holy Week (Monday through Saturday -- RG 91 entry 2's
+       Sacred Triduum, Thursday-Saturday, is a THIRD sub-case of this same
+       "feria", not a "festum": RG 35, immediately below in Caput VI,
+       defines "festum" as a distinct liturgical-day category from "feria",
+       RG 21-27) are FERIAE, never FESTA, however high their RG 91 rank --
+       so 475(b)/(c)'s "in festis" never reaches them, regardless of rank.
+
+       This single structural check subsumes 476(a)'s own explicit naming
+       of the Chrism Mass, the Mass of the Lord's Supper (both Holy
+       Thursday) and the Easter Vigil Mass (Holy Saturday's date): both are
+       already excluded here as Holy Week feriae, so 476(a) needs no
+       separate branch. (Good Friday needs no rubric at all -- RG 28's own
+       closing sentence on the Paschal Vigil aside, Good Friday's own
+       liturgical action has no Mass in the 1955-restored Holy Week to
+       begin with, so the question is moot there independent of this
+       check -- but this structural test correctly excludes it too, since
+       it is also named in RG 23(b).) *)
+    n = -46 || (n >= -6 && n <= -1)
+  then false
+  else if
+    (* RG 28-34 (Caput V, "De Vigiliis"): a vigil is its OWN liturgical-day
+       category, distinct from "festum" (RG 35, Caput VI) the same way a
+       feria is (immediately above) -- so 475(b)/(c)'s "in festis" does not
+       reach a vigil either, regardless of its own RG 91 rank. This is also
+       why 476(a) has to name the Easter Vigil explicitly: RG 28's own
+       closing sentence says the Paschal Vigil, uniquely, "non sit dies
+       liturgicus" [is not a liturgical day] at all, so it is not even a
+       "vigilia" in RG 29-32's numbered sense -- nothing else in this
+       taxonomy would have excluded it without that explicit clause, unlike
+       every OTHER vigil, which is excluded merely by being one.
+       {!Precedence_ef.is_vigil} already tests both slug conventions this
+       codebase's data uses (the temporal cycle's "-vigil" suffix and the
+       sanctoral bootstrap's "vigil-of-" prefix) for the identical RG 33
+       question; reused here rather than re-derived, on the same footing as
+       {!Precedence_ef.marian_slugs} just below. *)
+    Precedence_ef.is_vigil slug
+  then false
+  else if
+    (* RG 475(b): "in festis I classis". Genuine feasts only, by
+       construction of the two exclusions immediately above (feriae,
+       vigils) -- every remaining [Class1] candidate reaching this branch
+       is a real festum: the Nativity, Epiphany, Ascension, Corpus Christi,
+       the Sacred Heart, Christ the King, a I-class sanctoral feast (the
+       Assumption, the Immaculate Conception...), or a I-class Sunday
+       (already [true] above via 475(a), so this branch is never the FIRST
+       to grant those a [true], only ever redundant with it). *)
+    observed.Celebration.rank = Vocab_ef.Class1
+  then true
+  else if
+    (* RG 475(c): "in festis II classis Domini et B. Mariae Virg." --
+       [subject = Lord] is reliably set on genuine II-class sanctoral
+       feasts of the Lord (Exaltation of the Holy Cross, the Purification,
+       the Transfiguration, the Commemoration of the Baptism of the Lord,
+       the Dedication of the Lateran Archbasilica -- checked directly
+       against data/ef/sanctoral.sexp: six [subject = Lord] entries ship,
+       none a vigil or feria) and on the two temporal-cycle Class2 Lord
+       feasts (Holy Family, Holy Name of Jesus). [subject = Bvm], by
+       contrast, is NOT reliable for the BVM half: checked directly against
+       the data, almost every Marian sanctoral entry (the Assumption, the
+       Annunciation, the Immaculate Heart, the Nativity of the BVM...)
+       ships [subject = Saint] instead -- {!Precedence_ef.marian_slugs} is
+       the list built (and, here, reused rather than re-derived) precisely
+       because the [subject] field cannot be trusted alone for this
+       question; see its own citation in precedence_ef.mli. *)
+    observed.Celebration.rank = Vocab_ef.Class2
+    && (observed.Celebration.subject = Subject.Lord
+       || observed.Celebration.subject = Subject.Bvm
+       || List.mem slug Precedence_ef.marian_slugs)
+  then true
+  else
+    (* RG 475(e): see {!creed_apostle_slugs}'s own citation. Checked last
+       and without a rank guard, on purpose -- Barnabas is only [Class3]
+       and the Chair of St Peter's own [subject] is [Saint], so neither
+       would ever be reached by the two branches above; every [Class1]
+       entry on the list (Sts Peter & Paul) is already [true] via 475(b),
+       so this branch is redundant, never wrong, for those. *)
+    List.mem slug creed_apostle_slugs