Add Pirkei Avot Summer schedule

Port Pirkei Avot ("Ethics of the Fathers") from @hebcal/learning: one
chapter studied on each Shabbat of the summer between Pesach and Rosh
Hashana, the six-chapter cycle repeating with doubled chapters at the end
of the season. Computed from the Hebrew calendar with no fixed start
date; takes the il flag to select the Israel vs Diaspora schedule (8th
day Pesach / 2nd day Shavuot skips) and skips Erev/Tish'a B'Av Shabbatot.

Registered as "pirkeiAvotSummer"; events return event.DAILY_LEARNING.
Tested against the full 5783 (IL + Diaspora) and 5784 sequences from the
@hebcal/learning test suite.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: mjradwin

README.md

@@ -33,6 +33,8 @@ mirrors the relationship between `@hebcal/core` and `@hebcal/learning`:
     (~17-month cycle).
   - **psalms** — Daily Psalms (Tehillim) in the traditional 30-day cycle,
     completing the book of Psalms each Hebrew month.
+  - **pirkeiavot** — Pirkei Avot ("Ethics of the Fathers"), one chapter on
+    each Shabbat of the summer between Pesach and Rosh Hashana.
 
 ## Usage
 
@@ -86,14 +88,15 @@ The schedules register the following case-insensitive names with the
   - `dafWeeklySunday`
   - `perekYomi`
   - `psalms`
+  - `pirkeiAvotSummer`
 
 ## Roadmap
 
 The goal is to eventually port all of the daily learning schedules from
 the TypeScript [@hebcal/learning](https://github.com/hebcal/hebcal-learning)
 package. Still to port: Arukh HaShulchan Yomi, Sefer HaMitzvot, Chofetz
-Chaim, Shemirat HaLashon, Pirkei Avot, Tanakh Yomi, Kitzur Shulchan
-Aruch, Dirshu Amud Yomi, etc.
+Chaim, Shemirat HaLashon, Tanakh Yomi, Kitzur Shulchan Aruch, Dirshu
+Amud Yomi, etc.
 
 ## License
 

integration_test.go

@@ -26,7 +26,7 @@ import (
 func TestRegistry(t *testing.T) {
 	assert := assert.New(t)
 	assert.Equal(
-		[]string{"929", "dafweekly", "dafweeklysunday", "dafyomi", "mishnayomi", "nachyomi", "perekyomi", "psalms", "rambam1", "rambam3", "yerushalmi-schottenstein", "yerushalmi-vilna"},
+		[]string{"929", "dafweekly", "dafweeklysunday", "dafyomi", "mishnayomi", "nachyomi", "perekyomi", "pirkeiavotsummer", "psalms", "rambam1", "rambam3", "yerushalmi-schottenstein", "yerushalmi-vilna"},
 		dailylearning.GetCalendars(),
 	)
 

learning.go

@@ -21,6 +21,7 @@ import (
 	_ "github.com/hebcal/learning/nachyomi"
 	_ "github.com/hebcal/learning/nine29"
 	_ "github.com/hebcal/learning/perekyomi"
+	_ "github.com/hebcal/learning/pirkeiavot"
 	_ "github.com/hebcal/learning/psalms"
 	_ "github.com/hebcal/learning/rambam"
 	_ "github.com/hebcal/learning/yerushalmi"

pirkeiavot/event.go

@@ -0,0 +1,77 @@
+package pirkeiavot
+
+// Hebcal - A Jewish Calendar Generator
+// Copyright (c) 2026 Michael J. Radwin
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License
+// as published by the Free Software Foundation; either version 2
+// of the License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import (
+	"strconv"
+	"strings"
+
+	"github.com/hebcal/gematriya"
+	"github.com/hebcal/hdate"
+	"github.com/hebcal/hebcal-go/event"
+	"github.com/hebcal/hebcal-go/locales"
+)
+
+const pirkeiAvot = "Pirkei Avot"
+
+type pirkeiAvotEvent struct {
+	Date     hdate.HDate
+	Chapters []int
+}
+
+// NewPirkeiAvotSummerEvent returns a calendar event for the Pirkei Avot
+// chapter(s) studied on the given Shabbat.
+func NewPirkeiAvotSummerEvent(hd hdate.HDate, chapters []int) event.CalEvent {
+	return pirkeiAvotEvent{Date: hd, Chapters: chapters}
+}
+
+func (ev pirkeiAvotEvent) GetDate() hdate.HDate {
+	return ev.Date
+}
+
+func (ev pirkeiAvotEvent) Render(locale string) string {
+	book, _ := locales.LookupTranslation(pirkeiAvot, locale)
+	hebrew := false
+	if l := strings.ToLower(locale); l == "he" || l == "he-x-nonikud" {
+		hebrew = true
+	}
+	parts := make([]string, len(ev.Chapters))
+	for i, c := range ev.Chapters {
+		if hebrew {
+			parts[i] = gematriya.Gematriya(c)
+		} else {
+			parts[i] = strconv.Itoa(c)
+		}
+	}
+	return book + " " + strings.Join(parts, "-")
+}
+
+func (ev pirkeiAvotEvent) GetFlags() event.HolidayFlags {
+	return event.DAILY_LEARNING
+}
+
+func (ev pirkeiAvotEvent) GetEmoji() string {
+	return ""
+}
+
+func (ev pirkeiAvotEvent) Basename() string {
+	parts := make([]string, len(ev.Chapters))
+	for i, c := range ev.Chapters {
+		parts[i] = strconv.Itoa(c)
+	}
+	return pirkeiAvot + " " + strings.Join(parts, "-")
+}

pirkeiavot/pirkeiavot.go

@@ -0,0 +1,104 @@
+// Hebcal's pirkeiavot package calculates the Pirkei Avot ("Ethics of the
+// Fathers") summer schedule: one chapter studied on each Shabbat between
+// Pesach and Rosh Hashana, the six-chapter cycle repeating with doubled
+// chapters at the end to fill the season.
+//
+// https://en.wikipedia.org/wiki/Pirkei_Avot#Study_of_the_work
+package pirkeiavot
+
+// Hebcal - A Jewish Calendar Generator
+// Copyright (c) 2026 Michael J. Radwin
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License
+// as published by the Free Software Foundation; either version 2
+// of the License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import (
+	"time"
+
+	"github.com/hebcal/hdate"
+)
+
+// New returns the Pirkei Avot chapter(s) studied on the given Shabbat.
+//
+// The il argument selects the Israel schedule (no 8th day Pesach, no 2nd
+// day Shavuot) when true, or the Diaspora schedule when false.
+//
+// The second return value is false when the date is not a Pirkei Avot
+// Shabbat: not a Saturday, before Pesach, after Rosh Hashana, or a
+// Shabbat coinciding with a holiday on which Pirkei Avot is skipped (8th
+// day Pesach / 2nd day Shavuot in the Diaspora; Erev Tish'a B'Av or
+// Tish'a B'Av).
+func New(hd hdate.HDate, il bool) ([]int, bool) {
+	if hd.Weekday() != time.Saturday {
+		return nil, false
+	}
+	hyear := hd.Year()
+	pesach7 := hdate.New(hyear, hdate.Nisan, 21)
+	if hd.Abs() <= pesach7.Abs() {
+		return nil, false // before Pesach
+	}
+	first := pesach7.After(time.Saturday)
+	weekDiff := ceilDiv(hd.Abs()-first.Abs(), 7)
+
+	// When a holiday falls on Shabbat, Pirkei Avot is not studied; the same
+	// applies to Erev Tish'a B'Av.
+	var holidays []hdate.HDate
+	if !il {
+		// 8th day Pesach and 2nd day Shavuot are observed only in the Diaspora.
+		holidays = append(holidays, pesach7.Next(), hdate.New(hyear, hdate.Sivan, 7))
+	}
+	av8 := hdate.New(hyear, hdate.Av, 8)
+	holidays = append(holidays, av8, av8.Next()) // Erev 9 Av and Tish'a B'Av
+
+	for _, day := range holidays {
+		if day.Abs() == hd.Abs() {
+			return nil, false
+		}
+		if day.Abs()-hd.Abs() <= 0 && day.Weekday() == time.Saturday {
+			weekDiff-- // a holiday Shabbat already passed; don't count that week
+		}
+	}
+
+	if weekDiff < 0 {
+		return nil, false
+	} else if weekDiff < 18 {
+		return []int{int(weekDiff%6) + 1}, true
+	}
+
+	// The final round doubles up chapters to reach Rosh Hashana.
+	rh := hdate.New(hyear+1, hdate.Tishrei, 1)
+	last := rh.Before(time.Saturday)
+	weeksRemain := ceilDiv(last.Abs()-hd.Abs(), 7)
+	switch weeksRemain {
+	case 0:
+		return []int{5, 6}, true
+	case 1:
+		return []int{3, 4}, true
+	case 2:
+		if weekDiff%6 == 1 {
+			return []int{2}, true
+		}
+		return []int{1, 2}, true
+	case 3:
+		return []int{1}, true
+	}
+	return nil, false
+}
+
+// ceilDiv returns ceil(a/b) for b > 0, matching JavaScript Math.ceil.
+func ceilDiv(a, b int64) int64 {
+	if a >= 0 {
+		return (a + b - 1) / b
+	}
+	return -((-a) / b)
+}

pirkeiavot/pirkeiavot_test.go

@@ -0,0 +1,76 @@
+package pirkeiavot_test
+
+import (
+	"testing"
+	"time"
+
+	"github.com/hebcal/hdate"
+	"github.com/hebcal/learning/pirkeiavot"
+	"github.com/stretchr/testify/assert"
+)
+
+// collect returns the Pirkei Avot readings for every Shabbat from the
+// first Saturday on or after 21 Nisan through Erev Rosh Hashana, mirroring
+// the makeSaturdays helper in the @hebcal/learning test suite. A nil entry
+// represents a skipped Shabbat.
+func collect(year int, il bool) [][]int {
+	pesach7 := hdate.New(year, hdate.Nisan, 21)
+	fs := pesach7.OnOrAfter(time.Saturday)
+	firstSat := fs.Abs()
+	rh := hdate.New(year+1, hdate.Tishrei, 1)
+	erevRH := rh.Abs() - 1
+	var out [][]int
+	for abs := firstSat; abs <= erevRH; abs += 7 {
+		r, ok := pirkeiavot.New(hdate.FromRD(abs), il)
+		if !ok {
+			out = append(out, nil)
+		} else {
+			out = append(out, r)
+		}
+	}
+	return out
+}
+
+func TestPirkeiAvot5784Israel(t *testing.T) {
+	assert.Equal(t, [][]int{
+		{1}, {2}, {3}, {4}, {5}, {6},
+		{1}, {2}, {3}, {4}, {5}, {6},
+		{1}, {2}, {3}, {4}, {5}, {6},
+		{1}, {2}, {3, 4}, {5, 6},
+	}, collect(5784, true))
+}
+
+func TestPirkeiAvot5783Diaspora(t *testing.T) {
+	assert.Equal(t, [][]int{
+		{1}, {2}, {3}, {4}, {5}, {6},
+		nil, // 7 Sivan: 2nd day Shavuot
+		{1}, {2}, {3}, {4}, {5}, {6},
+		{1}, {2}, {3}, {4}, {5}, {6},
+		{1, 2}, {3, 4}, {5, 6},
+	}, collect(5783, false))
+}
+
+func TestPirkeiAvot5783Israel(t *testing.T) {
+	assert.Equal(t, [][]int{
+		{1}, {2}, {3}, {4}, {5}, {6},
+		{1}, {2}, {3}, {4}, {5}, {6},
+		{1}, {2}, {3}, {4}, {5}, {6},
+		{1}, {2}, {3, 4}, {5, 6},
+	}, collect(5783, true))
+}
+
+func TestPirkeiAvotNotShabbat(t *testing.T) {
+	// 24 Nisan 3759 is not a Pirkei Avot Shabbat.
+	_, ok := pirkeiavot.New(hdate.New(3759, hdate.Nisan, 24), true)
+	assert.False(t, ok)
+}
+
+func TestPirkeiAvotRender(t *testing.T) {
+	ev2 := pirkeiavot.NewPirkeiAvotSummerEvent(hdate.New(5783, hdate.Elul, 9), []int{2})
+	ev34 := pirkeiavot.NewPirkeiAvotSummerEvent(hdate.New(5783, hdate.Elul, 16), []int{3, 4})
+	assert.Equal(t, "Pirkei Avot 2", ev2.Render("en"))
+	assert.Equal(t, "Pirkei Avot 3-4", ev34.Render("en"))
+	assert.Equal(t, "Pirkei Avot 3-4", ev34.Basename())
+	assert.Equal(t, "פִּרְקֵי אָבוֹת ב׳", ev2.Render("he"))
+	assert.Equal(t, "פִּרְקֵי אָבוֹת ג׳-ד׳", ev34.Render("he"))
+}

pirkeiavot/register.go

@@ -0,0 +1,20 @@
+package pirkeiavot
+
+import (
+	"github.com/hebcal/hdate"
+	"github.com/hebcal/hebcal-go/dailylearning"
+	"github.com/hebcal/hebcal-go/event"
+)
+
+// Register the Pirkei Avot summer schedule with the dailylearning registry
+// under the name "pirkeiAvotSummer". It is purely computed from the Hebrew
+// calendar with no fixed start date, so no startDate is supplied.
+func init() {
+	dailylearning.AddCalendar("pirkeiAvotSummer", func(hd hdate.HDate, il bool) event.CalEvent {
+		chapters, ok := New(hd, il)
+		if !ok {
+			return nil
+		}
+		return NewPirkeiAvotSummerEvent(hd, chapters)
+	})
+}