1 files changed, 22 insertions, 5 deletions
diff --git a/internal/calendar/precedence_ef.go b/internal/calendar/precedence_ef.go
index 81862b7..4fda626 100644
--- a/internal/calendar/precedence_ef.go
+++ b/internal/calendar/precedence_ef.go
@@ -22,13 +22,30 @@ func efRankOrder(r Rank) int {
 }
 
 // precedenceEF ranks an EF candidate for occurrence (lower = higher precedence):
-// by class first, then — at equal class — the temporal office before the
-// sanctoral (a first-cut of the 1960 occurrence table; the missalemeum oracle
-// drives refinement).
+// by class first, then a tie-break at equal class (1960 occurrence table).
+//
+// The tie-break is asymmetric by season. An ORDINARY feria (per annum, Advent,
+// Septuagesima) yields to an equal-class feast — the feast is celebrated and the
+// feria commemorated (e.g. St Francis Xavier, Dec 3, on an Advent feria). The
+// ferias of Lent and Passiontide are privileged: they outrank an equal-class
+// feast, which is only commemorated. Sundays and named temporal feasts likewise
+// win their ties. The *2 class spacing means the ±1 tie-break never crosses a
+// class boundary.
 func precedenceEF(c candidate) int {
 	p := (6 - efRankOrder(c.Cel.Rank)) * 2 // class-1 -> 2, ferial -> 12
-	if !c.Temporal {
-		p++ // sanctoral yields to a temporal office of equal class
+	if c.Temporal {
+		ordinaryFeria := (c.Cel.Rank == RankClass3 || c.Cel.Rank == RankClass4) &&
+			c.Season != Lent && c.Season != Passiontide
+		if ordinaryFeria {
+			p++ // an ordinary feria yields to an equal-class feast
+		} else {
+			p-- // Sundays, named feasts, and penitential ferias win their ties
+		}
+	} else if c.Cel.Class == ClassLord && c.Cel.Rank == RankClass2 {
+		// A II class feast of the Lord takes the place of a II class Sunday it
+		// falls on (unlike a saint's feast, which is only commemorated). Give it
+		// the edge over the Sunday's tie-break bonus.
+		p -= 2
 	}
 	return p
 }