Boron

A multi-calendar, drop-in replacement for Carbon.

Boron (B) is element 5 of the periodic table. Carbon (C) is element 6. Boron sits right next to Carbon - a little lighter, and it knows more calendars. :)

Docs: boron.readthedocs.io

Boron adds a multi-calendar system on top of Carbon: Jalali (Shamsi / Solar Hijri), Hijri (Islamic / Lunar) and Gregorian, freely convertible to each other. You still get the entire Carbon feature set - diffing, localization, setTestNow(), CarbonInterface, everything.

The calendar engine is a PHP port of the Julian-Day-Number design of shahabyazdi/date-object, and every calendar is also available through a second driver backed by PHP's intl extension (ICU).

use Boron\Carbon;

Carbon::parse('2024-03-20')->toJalali();          // 1403-01-01 (Nowruz!)
Carbon::parse('2024-03-20')->toHijri();           // 1445-09-10 (Ramadan 10)
Carbon::fromJalali(1403, 5, 19)->toDateString();  // 2024-08-09

Carbon::now()->calendarFormat('l j F Y', 'jalali', 'fa', true);
// چهارشنبه ۱ فروردین ۱۴۰۳

The class family

Boron does not reinvent Carbon. It extends it:

Class	Extends	Use it when...
Boron\Carbon	Carbon\Carbon	mutable dates - Laravel's Date::use(), Eloquent casts, anything type-hinted against Carbon\Carbon
Boron\CarbonImmutable	Carbon\CarbonImmutable	immutable dates

Both implement Boron\CarbonInterface, which extends Carbon\CarbonInterface and adds the calendar API.

toImmutable() / toMutable() stay inside the Boron family and never leak plain Carbon instances; the active calendar travels along.

Installation

composer require boron/carbon

Requirements: PHP 8.1+, nesbot/carbon ^3.0. The intl extension is optional - it unlocks the ICU drivers (*-intl, hijri-umalqura).

Laravel

Supported: Laravel 11, 12 and 13 - Boron requires Carbon 3, which Laravel supports since v11.0.0 (nesbot/carbon: ^2.72.2|^3.0; Laravel 12+ requires Carbon 3 exclusively). Laravel 10 and below pin Carbon 2 and cannot be used with Boron.

The service provider is auto-discovered and calls Date::use(\Boron\Carbon::class), so now(), today(), Eloquent date casts, etc. all become calendar-aware:

use Illuminate\Support\Facades\Date;

Date::now()->toJalali();                    // works, returns CalendarDate
now()->toCalendarDateString('jalali');      // helpers return Boron\Carbon
User::first()->created_at->calendarFormat('Y/m/d', 'jalali');

Eloquent datetime casts yield Boron\Carbon and immutable_datetime casts yield Boron\CarbonImmutable, while JSON serialization of models keeps Laravel's standard ISO format. All of this is covered by the Testbench integration test suite (tests/Laravel).

Boron also registers itself with php artisan about (version, active calendar drivers, ICU availability).

Laravel Boost (AI agents)

Boron ships Laravel Boost assets, so AI agents in Boost-enabled projects automatically know how to use it:

• Guidelines (resources/boost/guidelines/core.blade.php) - always-on context loaded into CLAUDE.md/AGENTS.md by php artisan boost:install.
• Skill (resources/boost/skills/boron-development/SKILL.md) - the boron-development agent skill with in-depth usage patterns and pitfalls.

Calendars

Name	Aliases	Driver	Notes
gregorian	miladi	arithmetic	proleptic Gregorian
jalali	persian, shamsi	arithmetic	33-year cycle, aligned with ICU
jalali-astronomical	persian-astronomical	arithmetic	date-object astronomical table
hijri	islamic, arabic	arithmetic	tabular (civil) Islamic
jalali-intl	-	ICU	requires ext-intl
hijri-intl	-	ICU	Islamic civil (ICU)
hijri-umalqura	-	ICU	Saudi Umm al-Qura
hijri-astronomical	-	ICU	ICU islamic
gregorian-intl	-	ICU	ICU Gregorian (forced proleptic)

Caveats:

• Arithmetic jalali matches ICU day-for-day in the modern range; the astronomical driver can diverge by a day around a few historical leap years (1308/1309, 1341/1342, 1473/1474).
• Tabular hijri dates are a civil approximation and may differ by ±1 day from sighting-based calendars; use hijri-umalqura for the Saudi calendar.
• Supported range: year 1 of each calendar and later (Gregorian dates before 622 AD cannot be expressed in Jalali/Hijri and throw a range exception).

Usage

Converting

use Boron\Carbon;

$date = Carbon::parse('2024-03-20 15:30', 'Asia/Tehran');

$date->toJalali();               // CalendarDate: 1403-01-01
$date->toHijri();                // CalendarDate: 1445-09-10
$date->toCalendarDate('hijri-umalqura');  // any registered calendar
$date->julianDayNumber();        // 2460390

// CalendarDate is a small immutable value object:
$jalali = $date->toJalali();
$jalali->year;                   // 1403
$jalali->month;                  // 1
$jalali->day;                    // 1
$jalali->isLeapYear();           // true
$jalali->getMonthName('fa');     // فروردین
$jalali->to('hijri');            // convert again
$jalali->format('l j F Y', 'fa', true); // چهارشنبه ۱ فروردین ۱۴۰۳
$jalali->toCarbon('Asia/Tehran'); // back to Boron\Carbon at midnight

Creating

Carbon::fromJalali(1403, 1, 1);                     // 2024-03-20 00:00
Carbon::fromHijri(1445, 9, 10, 20, 30);             // with time
Carbon::fromCalendar('hijri-umalqura', 1445, 9, 1); // any calendar
Carbon::parseFromCalendar('jalali', '1403/01/01 14:30');
Carbon::parseFromCalendar('jalali', '۱۴۰۳/۰۱/۰۱');  // Persian digits OK

The active calendar

Each instance can carry an "active calendar" that calendar-aware members use by default. It does not change any Carbon behavior:

$date = Carbon::parse('2024-03-20')->withCalendar('jalali');

$date->calendarYear;         // 1403
$date->calendarMonth;        // 1
$date->calendarDay;          // 1
$date->calendarMonthName;    // Farvardin
$date->calendarDaysInMonth;  // 31
$date->calendarDayOfYear;    // 1
$date->toCalendarDateString();      // 1403-01-01
$date->toCalendarDateTimeString();  // 1403-01-01 00:00:00

$date->year;                 // 2024 - Carbon getters untouched
$date->format('Y-m-d');      // 2024-03-20 - Carbon format untouched

Or set it globally (shared by Carbon and CarbonImmutable):

Carbon::setDefaultCalendar('jalali');
Carbon::setDefaultCalendarLocale('fa');

Carbon::now()->toCalendarDateString();  // 1405-05-19

Formatting

calendarFormat() accepts PHP date() tokens. Date tokens (Y y m n d j t L z S F M l D N w) are rendered in the calendar; everything else (time, timezone, ...) is delegated to Carbon:

$date = Carbon::parse('2024-03-20 14:05')->withCalendar('jalali');

$date->calendarFormat('Y/m/d');            // 1403/01/01
$date->calendarFormat('j F Y H:i');        // 1 Farvardin 1403 14:05
$date->calendarFormat('j F Y', 'hijri');   // 10 Ramadan 1445
$date->calendarFormat('l j F Y', locale: 'fa', localizeDigits: true);
// چهارشنبه ۱ فروردین ۱۴۰۳

Calendar-aware arithmetic

Carbon's addMonth() etc. keep operating on the Gregorian calendar. For month/year math in the active calendar:

$date = Carbon::fromJalali(1403, 6, 31);       // Shahrivar 31

$date->addCalendarMonths(1);                  // 1403-07-30 (clamped, Mehr has 30 days)
Carbon::fromJalali(1403, 12, 30)->addCalendarYears(1);  // 1404-12-29 (clamped)

$date->startOfCalendarMonth();                // 1403-06-01 00:00:00
$date->endOfCalendarMonth();                  // 1403-06-31 23:59:59
$date->startOfCalendarYear();                 // 1403-01-01
$date->endOfCalendarYear();                   // 1403-12-30 (leap year!)

$date->setCalendarDate(1404, 1, 1);           // keeps time & timezone
$date->isCalendarLeapYear();                  // per active calendar

Day/hour/... arithmetic is calendar-independent - just use Carbon's own addDays(), addHours(), diffInDays(), ...

Immutability

use Boron\Carbon;
use Boron\CarbonImmutable;

$date = CarbonImmutable::now()->withCalendar('jalali');
$next = $date->addDay();     // new instance, calendar preserved

Carbon::now()->toImmutable();            // Boron\CarbonImmutable
CarbonImmutable::now()->toMutable();     // Boron\Carbon, never plain Carbon

Custom calendars

Implement Boron\Calendars\CalendarInterface (or reuse the ICU driver for any ICU calendar keyword) and register it:

use Boron\CalendarRegistry;
use Boron\Calendars\IcuCalendar;
use Boron\Carbon;

CalendarRegistry::register('buddhist', fn () => new IcuCalendar('buddhist'));

Carbon::now()->toCalendarDate('buddhist');

Testing

composer test

The suite includes a parity test that checks the arithmetic Jalali driver against ICU's Persian calendar for every day between 1900 and 2100, plus round-trip tests for all drivers over 1800-2200, and a Laravel integration suite running on Orchestra Testbench (Date facade, helpers, Eloquent casts, serialization).

Credits

• Hossein Hosni - author of Boron.
• Shahab Yazdi - the calendar engine design and the Persian astronomical leap-year table come from his date-object library.
• Brian Nesbitt, kylekatarnls & Carbon contributors for the Carbon foundation Boron builds on.
• ICU - the reference implementation behind the intl drivers.

License

MIT