Add nameLa mechanism for bilingual header, proof set of 11 feasts + St. Lawrence

Threads an optional nameLa field through SanctoralIdentity/SaintRecord/
TemporalFeastRecord/ActiveOctave so day-label.ts can render real Latin
proper names instead of always falling back to English. Authors the
proof set: all 11 named temporal feasts plus St. Lawrence (chosen to
exercise the octave-headline and octave-commemoration code paths too).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EwsZQMjALCvy7u9tFDWmuQ

src/calendar/collision.ts

@@ -19,11 +19,11 @@ export interface CollisionResult {
 }
 
 function asWinner(candidate: SanctoralIdentity): DayWinner {
-  return { kind: 'sanctoral', id: candidate.id, name: candidate.name, rank: candidate.rank };
+  return { kind: 'sanctoral', id: candidate.id, name: candidate.name, nameLa: candidate.nameLa, rank: candidate.rank };
 }
 
 function asCommemoration(candidate: SanctoralIdentity): Commemoration {
-  return { kind: 'sanctoral', id: candidate.id, name: candidate.name, rank: candidate.rank };
+  return { kind: 'sanctoral', id: candidate.id, name: candidate.name, nameLa: candidate.nameLa, rank: candidate.rank };
 }
 
 /**

src/calendar/commemorations.ts

@@ -83,11 +83,11 @@ export interface OccurrenceResult {
 }
 
 function sanctoralCommemoration(candidate: SanctoralIdentity): Commemoration {
-  return { kind: 'sanctoral', id: candidate.id, name: candidate.name, rank: candidate.rank };
+  return { kind: 'sanctoral', id: candidate.id, name: candidate.name, nameLa: candidate.nameLa, rank: candidate.rank };
 }
 
 function sanctoralWinner(candidate: SanctoralIdentity): DayWinner {
-  return { kind: 'sanctoral', id: candidate.id, name: candidate.name, rank: candidate.rank };
+  return { kind: 'sanctoral', id: candidate.id, name: candidate.name, nameLa: candidate.nameLa, rank: candidate.rank };
 }
 
 /**

src/calendar/day-label.ts

@@ -12,12 +12,14 @@
 //
 // Bilingual: every label is built as a `Bi` (`{en, la}`) pair throughout.
 // Proper names (a saint's name, an octave's name, a named temporal feast's
-// name) have no authored Latin form anywhere in `data/` today — those use
-// the English string as their own `la` value too (same "surface real text
-// rather than block on missing" convention used elsewhere in this app),
-// rather than leaving Latin mode showing blanks. Only the closed,
+// name) carry an optional `nameLa` field alongside the required English
+// `name` — see calendar/types.ts's `SanctoralIdentity.nameLa` doc comment.
+// Most saints still have no authored Latin name; `biName` falls back to
+// the English string as the `la` value in that case (same "surface real
+// text rather than block on missing" convention used elsewhere in this
+// app), rather than leaving Latin mode showing blanks. The closed,
 // mechanism-level vocabulary here (weekdays, ranks, season/ordinal
-// phrasing) has real Latin authored.
+// phrasing) has always had real Latin authored, independent of this.
 import type { FeastClass, LiturgicalDay, TemporalCategory, Weekday } from './types';
 import { easterSunday } from './easter';
 import { adventStart, firstSundayStrictlyAfter, sundayOnOrBefore } from './temporal';
@@ -36,10 +38,11 @@ function bi(en: string, la: string): Bi {
   return { en, la };
 }
 
-/** A proper name with no authored Latin form yet — the English string
- * stands in for `la` too. See file-header note. */
-function biFallback(name: string): Bi {
-  return { en: name, la: name };
+/** A proper name (saint, octave, named temporal feast) with an optional
+ * authored Latin form — falls back to the English string when `nameLa`
+ * hasn't been authored yet, same convention as `biFallback` above. */
+function biName(name: string, nameLa: string | undefined): Bi {
+  return { en: name, la: nameLa ?? name };
 }
 
 function joinBi(items: Bi[], sep = ' — '): Bi {
@@ -348,13 +351,13 @@ function temporalLabel(day: LiturgicalDay): Bi {
  * own winner is the feast itself, handled above before this is ever
  * called) — kept simple rather than special-cased for that rare edge case
  * (see applyOctaves's own `isOwnStartDay` comment in calendar/index.ts for
- * when it can happen). The octave's own `name` has no authored Latin form
- * (see file header), so both languages currently show the same name text
- * — only the surrounding phrasing differs. */
+ * when it can happen). Falls back to the English name for `la` too when
+ * the octave's own record has no authored `nameLa` yet (see file header). */
 function octaveCoreName(octave: ActiveOctave): Bi {
+  const name = biName(octave.name, octave.nameLa);
   return octave.isClosingDay
-    ? bi(`Octave of ${octave.name}`, `In Octava ${octave.name}`)
-    : bi(`${ordinal(octave.dayNumber)} Day within the Octave of ${octave.name}`, `${ordinalLa(octave.dayNumber)} die infra Octavam ${octave.name}`);
+    ? bi(`Octave of ${name.en}`, `In Octava ${name.la}`)
+    : bi(`${ordinal(octave.dayNumber)} Day within the Octave of ${name.en}`, `${ordinalLa(octave.dayNumber)} die infra Octavam ${name.la}`);
 }
 
 function octaveLabel(octave: ActiveOctave): Bi {
@@ -405,8 +408,8 @@ const CROSS_DAY_VESPERS_LABELS: Record<'today' | 'tomorrow', Bi> = {
  * - `sanctoral`: every commemorated saint, plain name, no rank (multiple
  *   real ones can coexist — e.g. two colliding saints on the same date —
  *   this app's own "generous commemorations" design keeps every one of
- *   them, not just the first). No authored Latin saint names exist yet
- *   (see file header), so `la` falls back to the same English name.
+ *   them, not just the first). `la` uses the saint's own `nameLa` when
+ *   authored, else falls back to the same English name (see file header).
  * - `temporal`: the day's own real Sunday/feria identity, if
  *   `decideOccurrence` demoted it to a commemoration (`ordinary-sunday`/
  *   `privileged-feria`/`privileged-feria-minor`) — matched by id against
@@ -438,7 +441,7 @@ function collectCommemorations(
   const octaves: Bi[] = [];
   for (const c of day.commemorations) {
     if (c.kind === 'sanctoral') {
-      const name = biFallback(c.name);
+      const name = biName(c.name, c.nameLa);
       sanctoral.push(
         c.vespersNote
           ? bi(`${name.en} (${CROSS_DAY_VESPERS_LABELS[c.vespersNote].en})`, `${name.la} (${CROSS_DAY_VESPERS_LABELS[c.vespersNote].la})`)
@@ -450,7 +453,7 @@ function collectCommemorations(
       }
     } else if (opts.showOctaves && c.id !== opts.excludeOctaveId) {
       const octave = activeOctaves.find((a) => a.id === c.id);
-      octaves.push(octave ? octaveCommemorationLabel(octave) : biFallback(c.name));
+      octaves.push(octave ? octaveCommemorationLabel(octave) : biName(c.name, c.nameLa));
     }
   }
   return { sanctoral, temporal, octaves };
@@ -542,7 +545,7 @@ export function getDayLabel(day: LiturgicalDay): Partial<Record<string, string>>
       showOctaves: day.temporalCategory === 'ordinary-feria',
     });
     const rank = formatRank(day.winner.rank);
-    const winnerName = biFallback(day.winner.name);
+    const winnerName = biName(day.winner.name, day.winner.nameLa);
     const winner = bi(`${winnerName.en} (${rank.en})`, `${winnerName.la} (${rank.la})`);
     return joinBi([winner, ...temporal, ...sanctoral, ...octaves]);
   }
@@ -554,7 +557,7 @@ export function getDayLabel(day: LiturgicalDay): Partial<Record<string, string>>
   // temporal-feasts.ts) and fall through further down.
   const namedFeast = getTemporalFeastRecord(day.winner.id);
   if (namedFeast) {
-    const name = biFallback(namedFeast.name);
+    const name = biName(namedFeast.name, namedFeast.nameLa);
     const primary = namedFeast.rank
       ? bi(`${name.en} (${formatRank(namedFeast.rank).en})`, `${name.la} (${formatRank(namedFeast.rank).la})`)
       : name;

src/calendar/feasts.ts

@@ -15,6 +15,9 @@ import sanctoralCalendarData from '../data/calendar/sanctoral-calendar.yml';
 export interface SaintRecord {
   id: string;
   name: string;
+  /** Latin form of `name`, when authored — see calendar/types.ts's
+   * `SanctoralIdentity.nameLa` doc comment for the display fallback. */
+  nameLa?: string;
   rank: FeastClass;
   common: string;
   propers: string | null;
@@ -138,6 +141,7 @@ for (const mod of Object.values(saintModules)) {
 export interface SanctoralCandidate {
   id: string;
   name: string;
+  nameLa?: string;
   rank: FeastClass;
 }
 
@@ -157,6 +161,6 @@ export function getSanctoralCandidatesFor(isoDate: string): SanctoralCandidate[]
     if (!saint) {
       throw new Error(`sanctoral-calendar.yml references unknown saint id '${id}'`);
     }
-    return { id: saint.id, name: saint.name, rank: saint.rank };
+    return { id: saint.id, name: saint.name, nameLa: saint.nameLa, rank: saint.rank };
   });
 }

src/calendar/index.ts

@@ -237,7 +237,7 @@ function applyChristmasOctaveSunday(
       if (idx !== -1) {
         commemorations.splice(idx, 1);
       }
-      return { kind: 'sanctoral', id: displaced.id, name: displaced.name, rank: displaced.rank };
+      return { kind: 'sanctoral', id: displaced.id, name: displaced.name, nameLa: displaced.nameLa, rank: displaced.rank };
     }
   }
 
@@ -290,7 +290,7 @@ function applyMarianSaturday(
   if (winner.rank !== 'simplex') {
     return winner;
   }
-  commemorations.push({ kind: 'sanctoral', id: winner.id, name: winner.name, rank: winner.rank });
+  commemorations.push({ kind: 'sanctoral', id: winner.id, name: winner.name, nameLa: winner.nameLa, rank: winner.rank });
   return MARIAN_SATURDAY;
 }
 
@@ -343,7 +343,7 @@ function applyOctaves(isoDate: string, winner: DayWinner, commemorations: Commem
     if (cmp < 0 || tiedAgainstClosingDay) {
       const isOneOfTheseOctaves = octaves.some((o) => o.id === winner.id);
       if (!isOneOfTheseOctaves) {
-        commemorations.push({ kind: 'sanctoral', id: winner.id, name: winner.name, rank: winner.rank });
+        commemorations.push({ kind: 'sanctoral', id: winner.id, name: winner.name, nameLa: winner.nameLa, rank: winner.rank });
         resolvedWinner = { kind: 'temporal', id: resolveTemporalId(isoDate) };
       }
     }
@@ -356,7 +356,7 @@ function applyOctaves(isoDate: string, winner: DayWinner, commemorations: Commem
     // again alongside itself would be redundant.
     const isOwnStartDay = octave.dayNumber === 1 && resolvedWinner.kind === 'temporal';
     if (!isSelf && !isOwnStartDay) {
-      commemorations.push({ kind: 'octave', id: octave.id, name: octave.name });
+      commemorations.push({ kind: 'octave', id: octave.id, name: octave.name, nameLa: octave.nameLa });
     }
   }
 

src/calendar/movable-feasts.ts

@@ -83,7 +83,7 @@ export function applyMovableFeasts(isoDate: string, winner: DayWinner, commemora
       if (resolvedWinner.kind === 'temporal') {
         commemorations.push({ kind: 'temporal', id: resolvedWinner.id });
       } else {
-        commemorations.push({ kind: 'sanctoral', id: resolvedWinner.id, name: resolvedWinner.name, rank: resolvedWinner.rank });
+        commemorations.push({ kind: 'sanctoral', id: resolvedWinner.id, name: resolvedWinner.name, nameLa: resolvedWinner.nameLa, rank: resolvedWinner.rank });
       }
       resolvedWinner = FEAST_WINNER;
       continue;
@@ -95,7 +95,7 @@ export function applyMovableFeasts(isoDate: string, winner: DayWinner, commemora
     } else if (compareFeastClass(resolvedWinner.rank, rank) >= 0) {
       commemorations.push({ kind: 'temporal', id: feast.id });
     } else {
-      commemorations.push({ kind: 'sanctoral', id: resolvedWinner.id, name: resolvedWinner.name, rank: resolvedWinner.rank });
+      commemorations.push({ kind: 'sanctoral', id: resolvedWinner.id, name: resolvedWinner.name, nameLa: resolvedWinner.nameLa, rank: resolvedWinner.rank });
       resolvedWinner = FEAST_WINNER;
     }
   }

src/calendar/octaves.ts

@@ -17,6 +17,9 @@ import { compareFeastClass, minimumOutrightWinningRank } from './commemorations'
 export interface ActiveOctave {
   id: string;
   name: string;
+  /** Latin form of `name`, when authored — see calendar/types.ts's
+   * `SanctoralIdentity.nameLa` doc comment for the display fallback. */
+  nameLa?: string;
   /** This octave's own effective rank *today* — the ordinary `wins`
    * threshold on every day except its own closing day, where it's
    * `closingDayRank` instead (see calendar/types.ts's OctaveConfig).
@@ -49,6 +52,7 @@ function considerCandidate(
   startDate: string,
   id: string,
   name: string,
+  nameLa: string | undefined,
   octave: OctaveConfig | undefined,
 ): void {
   if (!octave?.enabled || seen.has(id)) {
@@ -63,7 +67,7 @@ function considerCandidate(
   const dayNumber = offset + 1;
   const isClosingDay = dayNumber === days;
   const wins = isClosingDay ? (octave.closingDayRank ?? DEFAULT_CLOSING_DAY_RANK) : (octave.wins ?? DEFAULT_WINS);
-  active.push({ id, name, wins, dayNumber, isClosingDay });
+  active.push({ id, name, nameLa, wins, dayNumber, isClosingDay });
 }
 
 /** Every octave (sanctoral or temporal) whose window covers `isoDate`,
@@ -80,14 +84,14 @@ export function activeOctavesFor(isoDate: string): ActiveOctave[] {
     for (const candidate of getSanctoralCandidatesFor(candidateDate)) {
       const record = getSaintRecord(candidate.id);
       if (record) {
-        considerCandidate(active, seen, isoDate, candidateDate, record.id, record.name, record.octave);
+        considerCandidate(active, seen, isoDate, candidateDate, record.id, record.name, record.nameLa, record.octave);
       }
     }
 
     for (const feastId of temporalFeastIdsStartingOn(candidateDate)) {
       const record = getTemporalFeastRecord(feastId);
       if (record) {
-        considerCandidate(active, seen, isoDate, candidateDate, record.id, record.name, record.octave);
+        considerCandidate(active, seen, isoDate, candidateDate, record.id, record.name, record.nameLa, record.octave);
       }
     }
   }

src/calendar/temporal-feasts.ts

@@ -30,6 +30,9 @@ export type MovableAnchor =
 export interface TemporalFeastRecord {
   id: string;
   name: string;
+  /** Latin form of `name`, when authored — see calendar/types.ts's
+   * `SanctoralIdentity.nameLa` doc comment for the display fallback. */
+  nameLa?: string;
   octave?: OctaveConfig;
   rank?: FeastClass;
   anchor?: MovableAnchor;

src/calendar/types.ts

@@ -103,6 +103,11 @@ export type TemporalCategory =
 export interface SanctoralIdentity {
   id: string;
   name: string;
+  /** Latin form of `name`, when authored (see `data/calendar/saints/*.yml`'s
+   * own `nameLa` field). Absent for the majority of saints still — display
+   * code falls back to `name` itself when this is missing, same "surface
+   * real text rather than block on missing" convention used elsewhere. */
+  nameLa?: string;
   rank: FeastClass;
 }
 
@@ -180,7 +185,7 @@ export type Commemoration =
       // carries no such qualifier.
       vespersNote?: 'today' | 'tomorrow';
     } & SanctoralIdentity)
-  | { kind: 'octave'; id: string; name: string };
+  | { kind: 'octave'; id: string; name: string; nameLa?: string };
 
 export interface LiturgicalDay {
   /** ISO date, e.g. "2026-08-09" */

src/calendar/vespers.ts

@@ -85,7 +85,7 @@ function commemorationOfDisplacedPredecessor(loser: DayWinner): Commemoration |
   if (loser.kind !== 'sanctoral' || loser.rank === 'simplex') {
     return undefined;
   }
-  return { kind: 'sanctoral', id: loser.id, name: loser.name, rank: loser.rank, vespersNote: 'today' };
+  return { kind: 'sanctoral', id: loser.id, name: loser.name, nameLa: loser.nameLa, rank: loser.rank, vespersNote: 'today' };
 }
 
 /**
@@ -120,7 +120,7 @@ function commemorationOfDisplacedSuccessor(winner: DayWinner, loser: DayWinner):
   if (forbids) {
     return undefined;
   }
-  return { kind: 'sanctoral', id: loser.id, name: loser.name, rank: loser.rank, vespersNote: 'tomorrow' };
+  return { kind: 'sanctoral', id: loser.id, name: loser.name, nameLa: loser.nameLa, rank: loser.rank, vespersNote: 'tomorrow' };
 }
 
 function tagVespersFrom(tomorrow: LiturgicalDay): LiturgicalDay {

src/data/calendar/saints/st-lawrence.yml

@@ -6,6 +6,10 @@
 # antiphon.
 id: st-lawrence
 name: "St. Lawrence, Martyr"
+# Standard Latin form, matching this app's own "St. X, Rank" naming
+# convention (the source's own martyrology/kalendar entries for him use
+# the genitive "S. Laurentii Martyris", dependent on an implied "Festum").
+nameLa: "Sanctus Laurentius, Martyr"
 rank: duplex-2-classis
 common: common-of-a-martyr
 propers: "st-lawrence"

src/data/calendar/temporal-feasts/ascension.yml

@@ -15,6 +15,11 @@
 # — the `ordinary-feria` category was never actually load-bearing here.
 id: ascension
 name: "The Ascension of Our Lord"
+# Nominative form of the reference engine's own title ("In Ascensione
+# Domini", Pasc5-4.txt's [Officium]/[Rank] header), matching this app's
+# own nominative-noun-phrase naming convention rather than the source's
+# prepositional-phrase style.
+nameLa: "Ascensio Domini"
 rank: duplex-1-classis
 anchor:
   kind: easter

src/data/calendar/temporal-feasts/christ-the-king.yml

@@ -8,6 +8,11 @@
 # movable feast. See calendar/movable-feasts.ts for the occurrence rule.
 id: christ-the-king
 name: "Christ the King"
+# The feast's own traditional short Latin title (Pius XI's "Quas Primas"),
+# matching this app's nominative-noun-phrase naming convention — the
+# reference engine's own [Rank] title is genitive ("Domini Nostri Jesu
+# Christi Regis", Sancti/10-DU.txt), dependent on an implied "Festum".
+nameLa: "Christus Rex"
 rank: duplex-1-classis
 anchor:
   kind: nth-sunday-of-month

src/data/calendar/temporal-feasts/christmas-day.yml

@@ -12,6 +12,10 @@
 # specifically.
 id: christmas-day
 name: "Christmas"
+# Nominative form of the reference engine's own title ("In Nativitate
+# Domini", Sancti/12-25.txt's [Rank]), matching this app's own
+# nominative-noun-phrase naming convention.
+nameLa: "Nativitas Domini"
 rank: duplex-1-classis
 octave:
   enabled: true

src/data/calendar/temporal-feasts/circumcision.yml

@@ -20,6 +20,10 @@
 # not winner resolution at all.
 id: circumcision
 name: "The Circumcision of Our Lord"
+# Nominative form of the reference engine's own title ("In Circumcisione
+# Domini", Sancti/01-01.txt's [Rank]), matching this app's own
+# nominative-noun-phrase naming convention.
+nameLa: "Circumcisio Domini"
 rank: duplex-2-classis
 anchor:
   kind: fixed-date

src/data/calendar/temporal-feasts/corpus-christi.yml

@@ -14,6 +14,11 @@
 # day's real winner.
 id: corpus-christi
 name: "The Most Holy Body of Christ"
+# Common short Latin title, well attested in the reference engine's own
+# text ("Festum Sanctissimi Corporis Christi", Tempora/Pent01-4.txt's
+# [Officium]) — already a nominative noun phrase on its own, no
+# adaptation needed.
+nameLa: "Corpus Christi"
 rank: duplex-1-classis
 anchor:
   kind: easter

src/data/calendar/temporal-feasts/holy-name-of-jesus.yml

@@ -16,6 +16,10 @@
 # the day.
 id: holy-name-of-jesus
 name: "The Most Holy Name of Jesus"
+# Nominative form of the reference engine's own title ("Sanctissimi
+# Nominis Jesu", Sancti/01-00.txt's [Rank]), matching this app's own
+# nominative-noun-phrase naming convention.
+nameLa: "Sanctissimum Nomen Jesu"
 rank: duplex-2-classis
 anchor:
   kind: fixed-date

src/data/calendar/temporal-feasts/immaculate-heart-of-mary.yml

@@ -11,6 +11,10 @@
 # own content.
 id: immaculate-heart-of-mary
 name: "The Immaculate Heart of the Blessed Virgin Mary"
+# Nominative form of the reference engine's own title ("Immaculati Cordis
+# Beatæ Mariæ Virginis", Sancti/08-22.txt's [Rank]), matching this app's
+# own nominative-noun-phrase naming convention.
+nameLa: "Immaculatum Cor Beatæ Mariæ Virginis"
 rank: duplex-2-classis
 anchor:
   kind: easter

src/data/calendar/temporal-feasts/marian-saturday.yml

@@ -5,4 +5,9 @@
 # for how a day actually becomes this.
 id: marian-saturday
 name: "Our Lady's Saturday"
+# Adapted to a nominative noun phrase from the reference engine's own
+# title ("Sanctæ Mariæ Sabbato", Commune/C10.txt's [Officium] — an
+# ablative time-when construction, "on the Saturday of Holy Mary"),
+# matching this app's own nominative naming convention.
+nameLa: "Sabbatum Sanctæ Mariæ"
 rank: simplex

src/data/calendar/temporal-feasts/patronage-of-st-joseph.yml

@@ -21,6 +21,11 @@
 # (PascN-D = Easter + 7N + D, e.g. Ascension = Pasc5-4 = Easter+39).
 id: patronage-of-st-joseph
 name: "The Patronage of St. Joseph"
+# Nominative form of the reference engine's own title ("In Octava
+# Patrocinii S. Joseph", Tempora/Pasc3-3.txt's [Officium], octave-day
+# form of the feast's own genitive "Patrocinii S. Joseph"), matching this
+# app's own nominative-noun-phrase naming convention.
+nameLa: "Patrocinium Sancti Joseph"
 rank: duplex-1-classis
 anchor:
   kind: easter

src/data/calendar/temporal-feasts/pentecost-sunday.yml

@@ -10,6 +10,9 @@
 # before it gets the chance.
 id: pentecost-sunday
 name: "Pentecost"
+# Reference engine's own [Officium] title, Tempora/Pent00-0.txt — already
+# a nominative noun phrase, no adaptation needed.
+nameLa: "Dominica Pentecostes"
 rank: duplex-1-classis
 octave:
   enabled: true

src/data/calendar/temporal-feasts/sacred-heart.yml

@@ -10,6 +10,10 @@
 # temporal-feasts.ts's own doc comment) a record to live on.
 id: sacred-heart
 name: "The Most Sacred Heart of Our Lord Jesus Christ"
+# Nominative form of the reference engine's own title ("Sacratissimi
+# Cordis Domini Nostri Jesu Christi", Tempora/Pent02-5.txt's [Officium]),
+# matching this app's own nominative-noun-phrase naming convention.
+nameLa: "Sacratissimum Cor Domini Nostri Jesu Christi"
 rank: duplex-1-classis
 anchor:
   kind: easter