Calendrical version 0.8.0

[0.8.0] — 2026-05-24

Changed

• Function and module documentation across the calendar modules (Persian, Coptic, Hebrew, Ethiopic, Ethiopic.AmeteAlem, Buddhist, Indian, ROC, Julian and its variants, Ecclesiastical, Kday, Composite, Formatter, Chinese, Korean, LunarJapanese) is now in the project's standard template with ### Arguments, ### Returns, and ### Examples sections. Many functions gained their first doctest examples, taking the total doctest count from 410 to 509+.

• Calendrical.Julian now has a @moduledoc describing the proleptic Julian calendar and the year-shift variants (Calendrical.Julian.Jan1, .March1, .March25, .Sept1, .Dec25). Each variant now has its own short @moduledoc describing the historical year-style it represents.

Fixed

• Spelling fixes in calendar docs: calcualate → calculate (Persian leap-year doc), Arguements → Arguments, boolaan/booelan → boolean, Luanr → Lunar, sexigesimal → sexagesimal (Chinese, Korean, LunarJapanese).

• README installation snippet now points to ~> 0.8 instead of the stale ~> 0.1.0 from the initial release.

• README LICENSE link now points to v0.8.0 instead of v0.1.0.

• README Quick Start example for Calendrical.Interval.quarter/3 now shows the expected Date.range/2 result, matching the other examples in the block.

Calendrical version 0.7.0

[0.7.0] — 2026-05-23

Bug Fixes

• Calendrical.Time.parse/2 no longer lets narrow day-period markers (en's "a"/"p") consume the first letter of an adjacent capture. Previously "11:30 PST" against a h:mm a v pattern could match day_period="P" and zone="ST" (silently shifting 11:30 → 23:30 and losing the leading "P" of the zone); the day-period regex now requires a non-letter (or end of input) immediately after the match.

Added

• :as option on Calendrical.parse/2, Calendrical.Date.parse/2, Calendrical.Date.parse_range/2, Calendrical.Time.parse/2, and Calendrical.DateTime.parse/2. Pass as: :map to get a bare field map containing only what the input actually supplied ("May 5" → %{calendar: Calendar.ISO, month: 5, day: 5}, "11 am" → %{hour: 11}, "2026" → %{year: 2026}) instead of a struct with synthesised defaults — useful for downstream libraries that need the unresolved partial.

Calendrical version 0.6.0

[0.6.0] — 2026-05-23

Breaking changes

• Calendrical.DateParseError, TimeParseError, DateTimeParseError, DateRangeParseError, and ParseError no longer carry a :message struct field. The human-readable message is materialised by Exception.message/1 from the semantic fields (:input, :locale, :calendar, :reason, :from, :to, :cause, :attempts). Pattern-match on :reason (and other structural fields) rather than parsing the rendered string. DateRangeParseError now declares @behaviour Localize.Exception and exposes reason_atoms/0 for the closed set of failure categories; the :inverted reason carries :from/:to Date endpoints instead of stuffing them into :input.

Bug Fixes

• Calendrical.Date.parse_range/2 now returns a Date.Range whose endpoints are in the calendar named by the :calendar option (matching parse/2), instead of always returning Calendar.ISO endpoints. Date.Range supports any calendar provided both endpoints share it, so non-ISO ranges are well-formed.

• Month, day, era, quarter, and day-period name matching is now case-insensitive per CLDR TR35 §6.5 (Lenient Parsing). Previously "23 Mai" (capitalised) failed to parse in French because the parser case-sensitively matched the lowercase CLDR form "mai"; "23 mai" worked. All four parsers now accept any case for locale name fields.

• A literal space in a CLDR date pattern now requires at least one whitespace character in the input (previously zero-or-more). Inter-field gaps with no explicit pattern separator stay optional. This prevents over-greedy matches like "mai23" binding to a MMMM d y pattern as month=mai, day=2, year=3.

Added

• Calendrical.parse/2 — unified locale-aware parser that dispatches to the appropriate sub-parser when the input shape is not known up-front. Tries interval, date, time, then datetime, and returns {:ok, value} where value is a Date, Time, NaiveDateTime, DateTime, or Date.Range. Failures return {:error, Calendrical.ParseError.t()} whose :attempts field records each sub-parser tried.

• The :calendar option on all parsers now accepts either a CLDR calendar key atom (:gregorian, :hebrew, …) or a calendar module (Calendar.ISO, Calendrical.Hebrew, …). Modules are coerced via the cldr_calendar_type/0 callback; Calendar.ISO is treated as :gregorian.

• Calendrical.Date.parse/2 now accepts month-name + day input in either order regardless of the locale's preferred ordering. For any CLDR pattern with a name-form month (MMM/MMMM/MMMMM) and a numeric day, the parser also tries the reversed token order — so "May 23" parses in French (CLDR has d MMM) and "23 May" parses in English (CLDR has MMM d, y). Numeric M/MM are excluded because the swap would be ambiguous with d. Applies to year-bearing and weekday-bearing variants too; non-M-and-d tokens stay in place.

• ISO 8601 forms beyond Elixir stdlib are now accepted: basic format (20260523), ordinal date (2026-143), and ISO week date (2026-W21-6). Calendrical.Date.parse/2 recognises all three in every locale as a universal escape hatch alongside the existing extended format (2026-05-23).

• Calendrical.DateTime.parse/2 now accepts a space separator between date and time ("2026-05-23 14:30:00") in addition to T. Elixir stdlib's NaiveDateTime.from_iso8601/1 has accepted this form since 1.4; the gate has been relaxed so Calendrical does too. Common in SQL output, log lines, and human-readable timestamps.

• New parsing guide (guides/parsing.md) describing what each parser accepts, how Calendrical compares to Elixir stdlib, ISO 8601 coverage, and the documented variances from CLDR (case-insensitive name matching, M↔d swap, lenient separators).

Calendrical version 0.5.0

[0.5.0] — 2026-05-17

Breaking changes

• Calendrical.Date.parse/2 now returns the parsed Date in the calendar named by the :calendar option (e.g. ~D[5786-09-29 Calendrical.Hebrew] for calendar: :hebrew), instead of always returning Calendar.ISO. Pass return_calendar: :iso to force the previous behaviour.

• Calendrical.Date.parse_range/2 keeps returning ISO-Gregorian Date.Range endpoints — Date.Range is hard-coded to Calendar.ISO in Elixir stdlib.

Added

• TR35 date pattern letters — Q/q (quarter, format & standalone, widths 1–5), w (week of year), W (week of month), Y (week-based year), D (day of year), e/c (local day of week, numeric & names), F (day-of-week-in-month). E weekday names are now validated against the constructed date instead of consumed and discarded.

• TR35 flexible day periods (B) — Calendrical.Time.parse/2 recognises locale-specific flex period names ("in the morning", "at night", "noon", "midnight") and uses them to disambiguate AM/PM for 12-hour cycles when no a marker is present.

• TR35 time zone resolution — Calendrical.DateTime.parse/2 now returns a DateTime (with the correct UTC offset) when the input carries a zone token. Supported: ISO offsets (Z, ±HH:MM, ±HHMM), GMT/UTC format (GMT+10:30), IANA zones (Asia/Tokyo), short abbreviations (PST, EST, JST, …), and CLDR locale names (Pacific Time). New Calendrical.TimeZone.resolve/3. IANA-name resolution requires the host application to depend on :tzdata or :tz (detected at runtime); without one, IANA names fall back to a NaiveDateTime.

• All CLDR availableFormats skeletons are iterated on parse, not just the four dateStyle / timeStyle references. The standards are themselves keys into availableFormats, so this both subsumes the previous narrower set AND admits inputs like "3-5-1960" (matches :yMd skeleton "M/d/y" under lenient separator equivalence) and "week 20 of 2026" (matches :yw skeleton "'week' w 'of' Y").

• New Calendrical.Time.Parser.parse_with_zone/2 — same as parse/2 but also returns the captured zone string. Used by the DateTime parser; useful directly when a caller needs both the wall time and the original zone text.

• Plural-variant patterns in availableFormats (the %{one: ..., other: ...} shape on week-bearing skeletons like :yw) are now iterated, not silently dropped.

Bug Fixes

• Time-zone field regex (z/Z/v/V/O/X/x) tightened from the previous permissive [\p{L}\d:+\-/_]+ (which would happily eat "midnight") to require zone-shaped input — ISO offsets, GMT format, IANA region/city, uppercase abbreviation, or CLDR-style capital-led name.

• Time parser no longer requires the minute capture — skeletons like :Bh ("h B") that omit minutes now parse instead of erroring.

• Two-digit year pivot (yy) is correctly skipped for era-aware calendars (Japanese imperial, ROC) where the year is meant literally.

Calendrical version 0.4.0

[0.4.0] — 2026-05-17

Bug Fixes

• Calendrical.LunarJapanese.new/3, Calendrical.Chinese.new/3, and Calendrical.Korean.new/3 rejected valid {m, :leap} inputs in the documented traditional notation — the validator compared the user's traditional month number against the ordinal position returned by leap_month/1, which is always off by one. The check now correctly converts ordinal to traditional before comparing, the private helper has been renamed valid_traditional_date?/5 to disambiguate from the 3-arity valid_date?/3 callback used by Date.new/4, and the public Date.new/4 ordinal contract is unchanged.

• Test support module renamed from Calendrical.Date to Calendrical.Test.DateGenerator to free the Calendrical.Date namespace for the new parser module. Affects test/property_test.exs and test/day_of_week_test.exs only — no public API impact.

Added

• traditional_leap_month/1 on each of the three lunisolar calendars (Calendrical.LunarJapanese, Calendrical.Chinese, Calendrical.Korean), returning the traditional (1..12) number of the intercalary month — the number the leap month repeats — as a companion to leap_month/1 which returns the ordinal position (1..13).

• Calendrical.Time.parse/2 and Calendrical.DateTime.parse/2 — locale-aware time and date-time parsers completing the parser trio alongside Calendrical.Date.parse/2, TR35-compliant for hour-cycle resolution, day-period names, fractional seconds, and CLDR glue patterns. See the moduledocs for the day-period inheritance and datetime-glue backtracking strategy.

• Calendrical.TimeParseError and Calendrical.DateTimeParseError — structured errors carrying :input and :locale.

• Calendrical.Date.parse/2 — locale-aware parser for user-typed date strings across every Calendar-behaviour module exposing cldr_calendar_type/0 (Gregorian, Buddhist, Japanese imperial, Islamic, Persian, Hebrew, ROC, Coptic, Ethiopic, Indian, …). Handles CLDR lenient-scope-date separator equivalences, non-Latin digit transliteration, 2-digit year pivoting, and era markers — see Calendrical.Date.Parser for the full strategy.

• Calendrical.Date.parse_range/2 — locale-aware range parser. Accepts either a single string (split on CLDR's intervalFormatFallback separator) or a {from, to} tuple, with CLDR interval-skeleton inheritance so "May 5 – May 10, 2026" parses even though the left endpoint has no year.

• Calendrical.DateParseError and Calendrical.DateRangeParseError — structured errors carrying :input, :locale, :calendar, plus :reason and :cause for ranges.

Documentation

• Each lunisolar calendar's moduledoc now has a "Two month numbering conventions" section explaining the difference between ordinal months (used by Date.t, Date.new/4, Date.convert/2, and the Calendar callbacks) and traditional months (used by new/3 and the return value of lunar_month_of_year/1). The previous undocumented dichotomy could silently produce dates one full lunar month off after the intercalary in leap years.

• The new/3 and new!/3 docstrings on each lunisolar calendar now state explicitly that the lunar_month argument is traditional (1..12 with {m, :leap} for the intercalary), with examples showing how the traditional number maps to the ordinal stored on the resulting Date.t struct.

Calendarical v0.3.1

[0.3.1] — 2026-04-25

Bug Fixes

• Remove unnecessary require.

Calendrical version 0.3.0

[0.3.0] — 2026-04-22

Bug Fixes

• Fixes mapping CLDR calendar types to the implementation module name.

Calendrical version 0.2.0

[0.2.0] — 2026-04-16

This is the first release of Calendrical, which consolidates the ex_cldr_calendars library family into a single package built on Localize. Functionality from the following libraries has been merged in: ex_cldr_calendars, ex_cldr_calendars_persian, ex_cldr_calendars_coptic, ex_cldr_calendars_ethiopic, ex_cldr_calendars_japanese, ex_cldr_calendars_lunisolar, ex_cldr_calendars_islamic, ex_cldr_calendars_format, and ex_cldr_calendars_composite.

Added

• Calendrical.Behaviour — a defmacro __using__ template that supplies sensible default implementations of every Calendar and Calendrical callback. Calendars use the behaviour, supply an :epoch (and any non-default options), define date_to_iso_days/3 and date_from_iso_days/1, and override only the callbacks that differ from the defaults. Every generated function is defoverridable. See guides/calendar_behaviour.md.

• All 17 CLDR-acceptable calendar types are implemented:

  • Calendrical.Gregorian, Calendrical.ISO, Calendrical.ISOWeek, Calendrical.NRF — month- and week-based Gregorian calendars.

  • Calendrical.Julian and the year-start variants Calendrical.Julian.Jan1, Calendrical.Julian.March1, Calendrical.Julian.March25, Calendrical.Julian.Sept1, Calendrical.Julian.Dec25.

  • Calendrical.Buddhist — Thai Buddhist Era (Gregorian + 543).

  • Calendrical.Roc — Republic of China / Minguo (Gregorian − 1911).

  • Calendrical.Japanese — proleptic Gregorian with Japanese era data for localization.

  • Calendrical.Indian — Indian National (Saka) calendar with custom 30/31-day month structure and Saka era (Gregorian − 78).

  • Calendrical.Persian — astronomical Persian calendar based on the vernal equinox at Tehran, computed via Astro.equinox/2.

  • Calendrical.Coptic and Calendrical.Ethiopic — 13-month tabular calendars sharing the mod(year, 4) == 3 leap-year rule, with overridden quarter_of_year/3, day_of_week/4, and valid_date?/3.

  • Calendrical.Ethiopic.AmeteAlem — Ethiopic calendar with the Era of the World (Anno Mundi) year offset of +5500 over the standard Era of Mercy.

  • Calendrical.Islamic.Civil and Calendrical.Islamic.Tbla — tabular Hijri calendars with the Type II Kūshyār 30-year leap cycle. They share a private Calendrical.Islamic.Tabular helper and differ only in epoch (Friday 16 July 622 Julian vs Thursday 15 July 622 Julian).

  • Calendrical.Islamic.UmmAlQura — Saudi Umm al-Qura tabular calendar embedding the official KACST/van Gent first-of-month dataset (1356–1500 AH) at compile time. Conversions are O(1) forward and O(log n) reverse via binary search.

  • Calendrical.Islamic.UmmAlQura.Astronomical — Astronomical implementation of the Umm al-Qura rule using the Astro library's sunset/moonset and lunar phase functions for Mecca. Available for research and validation against the embedded table.

  • Calendrical.Islamic.Observational and Calendrical.Islamic.Rgsa — observational Islamic calendars using actual crescent visibility computed by Astro.new_visible_crescent/3 (Odeh 2006 criterion). The two share a private Calendrical.Islamic.Visibility helper and differ only in observation location (Cairo vs Mecca al-Masjid al-Ḥarām).

  • Calendrical.Hebrew — arithmetic Hebrew calendar with the molad of Tishri and Lo ADU Rosh postponement rules. Public API uses CLDR's Tishri = 1 month numbering with month 6 (Adar I) only valid in leap years. Overrides month_of_year/3 to return {7, :leap} for Adar II so localization picks up the CLDR 7_yeartype_leap variant.

  • Calendrical.Chinese, Calendrical.Korean (Dangi), and Calendrical.LunarJapanese — lunisolar calendars sharing a Calendrical.Lunisolar base implementation. Use Astro for lunar phase and winter solstice calculations at Beijing/Seoul/Tokyo respectively.

• Calendrical.Composite — a defmacro __using__ template for building composite calendars that use one base calendar before a specified date and a different calendar after. Supports any number of transitions chained together. The pre-built Calendrical.England and Calendrical.Russia modules demonstrate the historical Julian-to-Gregorian transitions.

• Calendrical.Era — an @after_compile hook that auto-generates a Calendrical.Era.<CalendarType> module from CLDR era data. Calendars use Calendrical.Behaviour get era support for free without writing any era boundary code. ETS-based locking coordinates module creation for calendars that share a cldr_calendar_type.

• Calendrical.localize/3 — locale-aware names for :era, :quarter, :month, :day_of_week, :days_of_week, :am_pm, and :day_periods parts of any date. Falls through to all 766+ CLDR locales available from Localize.Calendar. Handles the CLDR _yeartype_leap variant for Hebrew Adar II without needing month_patterns substitution.

• Calendrical.strftime_options!/1 — returns a keyword list compatible with Calendar.strftime/3 so the standard library's formatter can produce locale-aware output for any Calendrical calendar.

• Calendrical.shift_date/5 and Calendrical.shift_naive_datetime/9 — calendar-aware date/datetime shifting that supports the standard Date.shift/2 and NaiveDateTime.shift/2 APIs across every Calendrical calendar.

• Calendrical.Interval — Date.Range for years, quarters, months, weeks, and days in any supported calendar. The Calendrical.Interval.relation/2 function implements Allen's interval algebra (precedes, meets, overlaps, contains, …).

• Calendrical.Kday — finds the n-th occurrence of a given weekday relative to a date (e.g. "the second Tuesday in November", "the last Sunday before Christmas").

• Calendrical.FiscalYear — pre-built fiscal calendars for 50+ territories (US, AU, UK, JP, …). The Calendrical.FiscalYear.calendar_for/1 factory creates a fiscal calendar for any supported ISO 3166 territory code.

• Calendrical.Format and Calendrical.Formatter — calendar formatting via a behaviour-based plugin system. Includes Calendrical.Formatter.HTML.Basic, Calendrical.Formatter.HTML.Week, and Calendrical.Formatter.Markdown for rendering calendars to HTML and Markdown. Custom formatters can be added by implementing the Calendrical.Formatter behaviour.

• Calendrical.Parse — parses ISO-8601 date and datetime strings into the calling calendar via parse_date/1, parse_naive_datetime/1, and parse_utc_datetime/1.

• Calendrical.Preference — calendar_from_locale/1 and calendar_from_territory/1 return the preferred calendar for a CLDR locale or ISO 3166 territory.

• Calendrical.Ecclesiastical — Reingold-style algorithms for the dates of Christian liturgical events in a given Gregorian year, organized into three traditions:

  • Western (Roman Catholic / Anglican / most Protestants, Gregorian computus, results returned as Calendrical.Gregorian dates): easter_sunday/1, good_friday/1 (two days before), pentecost/1 (49 days after), advent/1 (the Sunday closest to 30 November), christmas/1 (25 December), epiphany/1 (first Sunday after 1 January, US observance).

  • Eastern Orthodox (Julian computus, results returned as Calendrical.Julian dates so the calendar context is visible): orthodox_easter_sunday/1, orthodox_good_friday/1 (two days before), orthodox_pentecost/1 (49 days after), orthodox_advent/1 (the start of the Nativity Fast on 15 November Julian — Eastern Orthodoxy has no movable "Advent Sunday" equivalent), eastern_orthodox_christmas/1 (25 December Julian, projected onto the Gregorian calendar).

  • Astronomical (the World Council of Churches' 1997 Aleppo proposal for unifying Western and Eastern Easter; not currently used by any Church, included for comparison; year range restricted to 1000..3000): astronomical_easter_sunday/1 (first Sunday strictly after the astronomical Paschal Full Moon), astronomical_good_friday/1 (two days before), paschal_full_moon/1 (the astronomical PFM itself, computed via Astro.equinox/2 and Astro.date_time_lunar_phase_at_or_after/2).

  Plus coptic_christmas/1 (29 Koiak Coptic) which doesn't fit cleanly into any of the three traditions.

  The module's moduledoc includes a comparison table showing the three Easter computations side-by-side.

• Eleven exception modules in lib/calendrical/exception/, one per file, modeled after the Localize convention. Each has semantic struct fields, an exception/1 constructor that takes a keyword list, and a message/1 callback that uses Gettext.dpgettext/5 for translation:

  • Calendrical.IncompatibleCalendarError — fields :from, :to.
  • Calendrical.IncompatibleTimeZoneError — fields :from, :to.
  • Calendrical.InvalidCalendarModuleError — field :module.
  • Calendrical.InvalidDateOrderError — fields :from, :to.
  • Calendrical.MissingFieldsError — fields :function, :fields.
  • Calendrical.InvalidPartError — fields :part, :valid_parts.
  • Calendrical.InvalidTypeError — fields :type, :valid_types.
  • Calendrical.InvalidFormatError — fields :format, :valid_formats.
  • Calendrical.IslamicYearOutOfRangeError — fields :year, :min_year, :max_year.
  • Calendrical.Formatter.UnknownFormatterError — field :formatter.
  • Calendrical.Formatter.InvalidDateError — field :date.
  • Calendrical.Formatter.InvalidOptionError — fields :option, :value.

• Calendrical.Gettext — gettext backend for the Calendrical library, using the "calendrical" domain with four contexts: "calendar", "date", "format", and "option".

• Embedded CLDR Umm al-Qura reference data sourced from R.H. van Gent's Utrecht University dataset (1356–1500 AH), cross-referenced against the KACST published tables. The data is e...