Date::Baha::i - Convert to and from Baha'i dates

Date-Baha-i documentation Contained in the Date-Baha-i distribution.

Index

Code Index:

NAME

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Date::Baha::i - Convert to and from Baha'i dates

SYNOPSIS

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  use Date::Baha'i;

  $bahai_date = to_bahai();
  $bahai_date = to_bahai(epoch => time);
  $bahai_date = to_bahai(
      year  => $year,
      month => $month,
      day   => $day,
  );

  %bahai_date = to_bahai();
  %bahai_date = to_bahai(epoch => time);
  %bahai_date = to_bahai(
      year  => $year,
      month => $month,
      day   => $day,
  );

  $date = from_bahai(
      year  => $bahai_year,
      month => $bahai_month,
      day   => $bahai_day,
  );

  ($year, $month, $day) = from_bahai(
      year  => $bahai_year,
      month => $bahai_month,
      day   => $bahai_day,
  );

  $day = next_holy_day();
  $day = next_holy_day($year, $month, $day);

  @cycles = cycles();
  @years = years();
  @months = months();
  @days = days();
  @days = days_of_the_week();
  %days = holy_days();

DESCRIPTION

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This package renders the Baha'i date from two standard date formats - epoch time and a (year, month, day) triple. It also converts a Baha'i date to standard ymd format.

The following are excerpts from the SEE ALSO section

EXCERPT 1

This calendar was instituted by the Baha'i spiritual leader Baha'u'llah, who stated that it should begin in the Gregorian year 1844 at the (northern) Spring equinox, which is the traditional Iranian New Year. According to calendars rules, the year begins at the sunset following the equinox, but up to now the practice in the West has been to start the year at sunset on 20 March. This is usually shown as 21 March, with the understanding that the day begins on the evening before. In the Middle East, Baha'is start the year at the sunset in Tehran following the equinox, and the Baha'i Universal House of Justice has not yet decided on the rules of the calendar to be used by all (Reingold and Dershowitz: Calendrical Calculations 2001). For now, I present the calendar as used in the West.

Baha'u'llah proclaimed the fulfillment of all religions and the unity of humankind, and the calendar is designed to be a world calendar, (relatively) free of cultural baggage. It is an entirely solar calendar, without even the vestige of previously lunar months as in the Gregorian Calendar.

EXCERPT 2

The Baha'i year is based on the solar year of 365 days, five hours and some fifty minutes. Each year is divided into nineteen months of nineteen days each with four Intercalary Days (five in a leap year), called Ayyam-i-Ha which Baha'u'llah specified should precede the nineteenth month.

EXCERPT 3

The number nineteen has a special significance for Baha'is. It was common in Persian mystical writings to utilize a system of numerical values to convey meanings beyond what mere words could impart. Within this system, words are assigned numerical values, and relationships between words can be implied based upon these values. The word "vahid", meaning unity, has the numerical value of nineteen, and is often used by the Bab and Baha'u'llah when specifying the quantity nineteen. So the number nineteen, in addition to being a quantity, also is evocative of the central teaching of the Baha'i Faith: unity. It forms the basis not only of the calendar, but also was integral to the structure of the Persian Bayan (the Bab's Book of laws); is found in Baha'u'llah's laws concerning dowries, the payment of Huquq'u'llah, certain fines, and various prayers; and is even seen in the history of the Faith, as Baha'u'llah's public declaration of His mission took place nineteen years after the Bab's declaration.

Finally, for those who like to go into excruciating detail, the Bab also spoke of time periods longer than a year. He grouped years into "Vahids" of nineteen years each, and gave each Vahid a name. (It is here that the word "Badi" appears, as the name of the sixteenth year in the cycle.) He further grouped the Vahids themselves into sets of nineteen to create a time period called a "Kull-i-Shay" (literally, "all things"). One Kull-i-Shay is therefore 361 years.

DAY NAMES

The days of the Baha'i week are:

  1. Jalal    - Glory (Saturday)
  2. Jamal    - Beauty (Sunday)
  3. Kaml     - Perfection (Monday)
  4. Fidal    - Grace (Tuesday)
  5. 'Idal    - Justice (Wednesday)
  6. Istijlal - Majesty (Thursday)
  7. Istiqlal - Independence (Friday)

The Baha'i day of rest is Isiqlal (Friday) and the Baha'i day begins and ends at sunset.

MONTH NAMES

The names of the months in the Baha'i (Badi) calendar were given by the Bab, who drew them from the nineteen names of God invoked in a prayer said during the month of fasting in Shi'ih Islam. They are:

  1.  Baha       - Splendour (21 March - 8 April)
  2.  Jalal      - Glory (9 April - 27 April)
  3.  Jamal      - Beauty (28 April - 16 May)
  4.  'Azamat    - Grandeur (17 May - 4 June)
  5.  Nur        - Light (5 June - 23 June)
  6.  Rahmat     - Mercy (24 June - 12 July)
  7.  Kalimat    - Words (13 July - 31 July)
  8.  Kamal      - Perfection (1 August - 19 August)
  9.  Asma'      - Names (20 August - 7 September)
  10. 'Izzat     - Might (8 September - 26 September)
  11. Mashiyyat  - Will (27 September - 15 October)
  12. 'Ilm       - Knowledge (16 October - 3 November)
  13. Qudrat     - Power (4 November - 22 November)
  14. Qawl       - Speech (23 November - 11 December)
  15. Masa'il    - Questions (12 December - 30 December)
  16. Sharaf     - Honour (31 December - 18 January)
  17. Sultan     - Sovereignty (19 January - 6 February)
  18. Mulk       - Dominion (7 February - 25 February)
  *   Ayyam-i-Ha - Days of Ha (26 February - 1 March))
  19. 'Ala       - Loftiness (2 March - 20 March)

AYYAM-I-HA

Literally, Days of Ha (i.e. the letter Ha, which in the abjad system has the numerical value of 5). Intercalary Days. The four days (five in a leap year) before the last month of the Baha'a year, "Ala."

CYCLES

Each cycle of nineteen years is called a Vahid. Nineteen cycles constitute a period called Kull-i-Shay.

The names of the years in each cycle are: 

  1.  Alif   - The Letter "A"
  2.  Ba     - The letter "B"
  3.  Ab     - Father
  4.  Dal    - The letter "D"
  5.  Bab    - Gate
  6.  Vav    - The letter "V"
  7.  Abad   - Eternity
  8.  Jad    - Generosity
  9.  Baha   - Splendour
  10. Hubb   - Love
  11. Bahhaj - Delightful
  12. Javab  - Answer
  13. Ahad   - Single
  14. Vahhab - Bountiful
  15. Vidad  - Affection
  16. Badi   - Beginning
  17. Bahi   - Luminous
  18. Abha   - Most Luminous
  19. Vahid  - Unity

HOLY DAYS

There are eleven Holy Days which Baha'is celebrate.

* Naw Ruz - (Generally) March 21

Literally, New Day. The Baha'i New Year. Like the ancient Persian New Year, it occurs on the Spring equinox, which generally falls on 21 March. If the equinox falls after sunset on 21 March, Naw Ruz is celebrated on 22 March, since the Baha'i day begins at sunset. For the present, however, the celebration of Naw Ruz is fixed on 21 March. In the Baha'i calandar, Naw Ruz falls on the day of Baha of the month of Baha. The Festival of Naw Ruz marks the end of the month of fasting and is a joyous time of celebration. It is a Baha'i Holy Day on which work is to be suspended.

* Ridvan

First day - 21 April; Ninth day - 29 April; Twelfth (last) day - 2 May

The Ridvan (pronouced "riz-wan") festival commemorates the first public declaration by Baha'u'llah of His Station and mission (in 1863).

* Declaration of the Bab - 23 May

Commemorates the date in 1844 when the Bab first declared His Mission.

* Ascension of Baha'u'llah - 29 May

Commemorates the date in 1892 when Baha'u'llah passed away.

* Martyrdom of the Bab - 9 July

Commemorates the date in 1850 when the Bab was executed in Tabriz, Iran.

* Birth of the Bab - 20 October

Commemorates the date in 1819 when the Bab was born in Shiraz, Iran.

* Birth of Baha'u'llah - 12 November

Commemorates the date in 1817 when Baha'u'llah was born in Tihran, Iran.

- Work does not have to cease on these Holy Days:

* Day of the Covenant - 26 November

This day is celebrated in lieu of the Birth of 'Abdu'l-Baha, which falls on the same day as the Declaration of the Bab.

* Ascension of 'Abdu'l-Baha - 28 November

Commemorates the day in 1921 when 'Abdu'l-Baha passed away.

* Ayyam-i-Ha (the Intercalary Days) 26 February - 1 March

The Baha'i calendar is made up of 19 months of 19 days each. The period of Ayyam-i-Ha adjusts the Baha'i year to the solar cycle. These days are set aside for hospitality, gift-giving, special acts of charity, and preparing for the Baha'i Fast.

* The Fast - 'Ala - Loftiness (month 19) / 2-20 March

Baha'is fast for 19 days from sunrise to sunset.

EXPORT

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to_bahai

  # Return a string in scalar context.
  $bahai_date = to_bahai();
  $bahai_date = to_bahai(
      epoch => time,
      use_gmtime => $use_gmtime,
      %args,
  );
  $bahai_date = to_bahai(
      year  => $year,
      month => $month,
      day   => $day,
      %args,
  );

  # Return a hash in array context.
  %bahai_date = to_bahai();
  %bahai_date = to_bahai(
      epoch => time,
      use_gmtime => $use_gmtime,
      %args,
  );
  %bahai_date = to_bahai(
      year  => $year,
      month => $month,
      day   => $day,
      %args,
  );

This function returns either a string or a hash of the Baha'i date names and numbers from either epoch seconds or a year, month, day triple.

If using epoch seconds, this function can be forced to use gmtime instead of localtime. If neither a epoch or ymd triple are given, the system localtime (or gmtime) are used as a default.

The extra arguments are most handy, and used by the as_string function, detailed below.

In a scalar context, this function returns a string sentence with the numeric and/or named Baha'i date. In an array context, it returns a hash with the following keys:

  kull_i_shay,
  cycle, cycle_name, cycle_year,
  year, year_name,
  month, month_name,
  day, day_name,
  dow, dow_name and
  holy_day (if there is one)

from_bahai

  # Return a y/m/d string in scalar context.
  $date = from_bahai(
      year  => $bahai_year,
      month => $bahai_month,
      day   => $bahai_day,
  );

  # Return a ymd triple in array context.
  ($year, $month, $day) = from_bahai(
      year  => $bahai_year,
      month => $bahai_month,
      day   => $bahai_day,
  );

This function returns either a string or a list of the standard date from a year, month, day triple of the Baha'i date.

Currently, this only supports the Baha'i year, month and day.

as_string

  $date = as_string(
      \%bahai_date,
      size     => $size,
      alpha    => $alpha,
      numeric  => $numeric,
  );

Return the Baha'i date as a friendly string.

This function takes a Baha'i date hash and Boolean arguments that determine the format of the output.

The "size" argument toggles between short and long representations. As the names imply, the "alpha" and "numeric" flags turn the alphanumeric representations on or off. The defaults are as follows:

  alpha    => 1
  numeric  => 0
  size     => 1

Which mean that "long non-numeric alpha" is the default representation.

Here are some handy examples (newlines added for readability):

  short numeric:
  1/1/159

  short numeric:
  1/1/159

  long numeric:
  7th day of the week, 1st day of the 1st month, year 159,
  7th year of the 9th vahid of the 1st kull-i-shay, holy day: Naw Ruz

  long numeric:
  7th day of the week, 1st day of the 1st month, year 159,
  7th year of the 9th vahid of the 1st kull-i-shay, holy day: Naw Ruz

  short alpha:
  Istiqlal, Baha of Baha, Abad of Baha

  short alpha
  Istiqlal, Baha of Baha, Abad of Baha

  long alpha:
  week day Istiqlal, day Baha of month Baha,
  year one hundred fifty nine of year Abad of the vahid Baha of the
  1st kull-i-shay, holy day: Naw Ruz

  long alpha:
  week day Istiqlal, day Baha of month Baha,
  year one hundred fifty nine of year Abad of the vahid Baha of the
  1st kull-i-shay, holy day: Naw Ruz

  short alpha-numeric:
  Istiqlal (7), Baha (1) of Baha (1), year 159, Abad (7) of Baha (9)

  short alpha-numeric:
  Istiqlal (7), Baha (1) of Baha (1), year 159, Abad (7) of Baha (9)

  long alpha-numeric:
  7th week day Istiqlal, 1st day Baha of the 1st month Baha,
  year one hundred and fifty nine (159), 7th year Abad of the
  9th vahid Baha of the 1st kull-i-shay, holy day: Naw Ruz

  long alpha-numeric:
  7th week day Istiqlal, 1st day Baha of the 1st month Baha,
  year one hundred and fifty nine (159), 7th year Abad of the
  9th vahid Baha of the 1st kull-i-shay, holy day: Naw Ruz

next_holy_day

  $d = next_holy_day();
  $d = next_holy_day($year, $month, $day);

This function returns the name of the first holy day after the provided date triple.

cycles

  @c = cycles();

This function returns the 19 cycle names as an array.

years

  @y = years();

This function returns the 19 year names as an array.

months

  @m = months();

This function returns the 19 month names as an array, along with the intercalary days (Ayyam-i-Ha) as the last element.

days

  @d = days();

This function returns the 19 day names as an array.

days_of_the_week

  @d = days_of_the_week();

This function returns the seven day-of-the-week names as an array.

holy_days

  %d = holy_days();

This function returns the a hash, where the keys are the Holy Day names and the values are array references, of either two or three elements: month, day and the (optional) number of days observed. These dates are given in standard (non-Baha'i) format.

SEE ALSO

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Date::Calc

Lingua::EN::Numbers

Lingua::EN::Numbers::Years

http://www.projectpluto.com/calendar.htm#bahai (Very interesting)

The following are partially quoted above:

http://www.planetbahai.org/articles/2003/ar032103a.html

http://www.bahaindex.com/calendar.html

http://www.moonwise.co.uk/year/160bahai.htm

TO DO

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Base the date computation on the time of day (the Baha'i day begins at sunset) with Astro::Sunrise.

Make this a DateTime module...

Support cycles and Kull-i-Shay.

Overload localtime and gmtime, just to be cool?

AUTHOR

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Gene Boggs, <gene at cpan.org>

LICENSE AND COPYRIGHT

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Copyright 2003-2010 Gene Boggs.

This program is free software; you can redistribute it and/or modify it under the terms of either: the GNU General Public License as published by the Free Software Foundation; or the Artistic License.

See http://dev.perl.org/licenses/ for more information.

Date-Baha-i documentation Contained in the Date-Baha-i distribution. 
package Date::Baha::i;

our $VERSION = '0.1902';
use strict;
use warnings;
use Date::Calc qw(
    Add_Delta_Days
    Date_to_Days
    Day_of_Week
    leap_year
);
use Lingua::EN::Numbers qw(num2en_ordinal);
use Lingua::EN::Numbers::Years;
use base 'Exporter';
use vars qw(@EXPORT @EXPORT_OK);
@EXPORT = @EXPORT_OK = qw(
    as_string
    cycles
    days
    days_of_the_week
    from_bahai
    holy_days
    months
    next_holy_day
    to_bahai
    years
);

# Set constants
use constant FACTOR         =>   19;  # Everything is in groups of 19.
use constant FEBRUARY       =>    2;
use constant MARCH          =>    3;
use constant SHARAF         =>   16;
use constant LAST_START_DAY =>    2;  # First day of the fast.
use constant YEAR_START_DAY =>   21;  # Vernal equinox.
use constant LEAP_START_DAY =>   26;  # The intercalary days.
use constant FIRST_YEAR     => 1844;
use constant ADJUST_YEAR    => 1900;
use constant CYCLE_YEAR => qw(
    Alif
    Ba
    Ab
    Dal
    Bab
    Vav
    Abad
    Jad
    Baha
    Hubb
    Bahhaj
    Javab
    Ahad
    Vahhab
    Vidad
    Badi
    Bahi
    Abha
    Vahid
);

use constant MONTH_DAY => qw(
    Baha
    Jalal
    Jamal
    'Azamat
    Nur
    Rahmat
    Kalimat
    Kamal
    Asma'
    'Izzat
    Mashiyyat
    'Ilm
    Qudrat
    Qawl
    Masa'il
    Sharaf
    Sultan
    Mulk
    'Ala
    Ayyam-i-Ha
);

# NOTE: Trailing 0's are stripped, resulting in incorrect
# computations if certain decimals are not quoted...
# So I just quote everything.
#   Month name   => [Number, Start, End],    # Non-leap year day span
use constant MONTHS => {
    "Baha"       => [ 0,  '3.21',  '4.08'],  # 80,  98
    "Jalal"      => [ 1,  '4.09',  '4.27'],  # 99, 117
    "Jamal"      => [ 2,  '4.28',  '5.16'],  #118, 136
    "'Azamat"    => [ 3,  '5.17',  '6.04'],  #137, 155
    "Nur"        => [ 4,  '6.05',  '6.23'],  #156, 174
    "Rahmat"     => [ 5,  '6.24',  '7.12'],  #175, 193
    "Kalimat"    => [ 6,  '7.13',  '7.31'],  #194, 212
    "Kamal"      => [ 7,  '8.01',  '8.19'],  #213, 231
    "Asma'"      => [ 8,  '8.20',  '9.07'],  #232, 250
    "'Izzat"     => [ 9,  '9.08',  '9.26'],  #251, 269
    "Mashiyyat"  => [10,  '9.27', '10.15'],  #270, 288
    "'Ilm"       => [11, '10.16', '11.03'],  #289, 307
    "Qudrat"     => [12, '11.04', '11.22'],  #308, 326
    "Qawl"       => [13, '11.23', '12.11'],  #327, 345
    "Masa'il"    => [14, '12.12', '12.30'],  #346, 364
    "Sharaf"     => [15, '12.31',  '1.18'],  #365,  18
    "Sultan"     => [16,  '1.19',  '2.06'],  # 19,  37
    "Mulk"       => [17,  '2.07',  '2.25'],  # 38,  56
    "Ayyam-i-Ha" => [-1,  '2.26',  '3.01'],  # 57,  60
    "'Ala"       => [18,  '3.02',  '3.20'],  # 61,  79
};

use constant DOW_NAME => qw(
    Jalal
    Jamal
    Kaml
    Fidal
    'Idal
    Istijlal
    Istiqlal
);

use constant HOLY_DAYS => {
    # Work suspended':
    "Naw Ruz"                   => [  '3.21' ],
    "First Day of Ridvan"       => [  '4.21' ],
    "Ninth Day of Ridvan"       => [  '4.29' ],
    "Twelfth Day of Ridvan"     => [  '5.02' ],
    "Declaration of the Bab"    => [  '5.23' ],
    "Ascension of Baha'u'llah"  => [  '5.29' ],
    "Martyrdom of the Bab"      => [  '7.09' ],
    "Birth of the Bab"          => [ '10.20' ],
    "Birth of Baha'u'llah"      => [ '11.12' ],
    # Work not suspended:
    "Ayyam-i-Ha"                => [  '2.26',  4 ],  # 5 days are calculated in leap years
    "The Fast"                  => [  '3.02', 19 ],
    "Days of Ridvan"            => [  '4.21', 12 ],
    "Day of the Covenant"       => [ '11.26' ],
    "Ascension of 'Abdu'l-Baha" => [ '11.28' ],
};


# List return functions
sub cycles { return CYCLE_YEAR }
sub years { return CYCLE_YEAR }
sub months { return MONTH_DAY }
sub days { return (MONTH_DAY)[0 .. 18] }
sub days_of_the_week { return DOW_NAME }
sub holy_days { return HOLY_DAYS }


sub to_bahai {
    my %args = @_;

    # Grab the ymd from the arguments if they have been passed in.
    my($year, $month, $day) = @args{qw(year month day)};
    # Make sure we have a proper ymd before proceeding.
    ($year, $month, $day) = _ymd(
        %args,
        year  => $year,
        month => $month,
        day   => $day,
    );

    my($bahai_month, $bahai_day);

    for(values %{ MONTHS() }) {
        my($days, $lower, $upper) = _setup_date_comparison(
            $year, $month, $day, @$_[1,2]
        );

        if($days >= $lower && $days <= $upper) {
            $bahai_month = $_->[0];
            $bahai_day = $days - $lower;
            last;
        }
    }

    # Build the date hash to return.
    return _build_date(
        $year, $month, $day, $bahai_month, $bahai_day,
        %args
    );
}


sub from_bahai {
    my %args = @_;

    # Figure out the year.
    my $year = $args{year} + FIRST_YEAR;
    $year-- unless $args{month} > SHARAF || $args{month} == -1;

    # Reset the month number if we are given Ayyam-i-Ha.
    $args{month} = 0 if $args{month} == -1;

    # This ugliness actually finds the month and day number.
    my $day = (MONTHS->{ (MONTH_DAY)[$args{month} - 1] })->[1];
    (my $month, $day) = split /\./, $day;
    ($year, $month, $day) = Add_Delta_Days(
        $year, $month, $day, $args{day} - 1
    );

    return wantarray
        ? ($year, $month, $day)
        : join '/', $year, $month, $day;
}

sub as_string {
    # XXX With Lingua::EN::Numbers, naively assume that we only care about English.
    my($date_hash, %args) = @_;

    $args{size}     = 1 unless defined $args{size};
    $args{numeric}  = 0 unless defined $args{numeric};
    $args{alpha}    = 1 unless defined $args{alpha};

    my $date;

    my $is_ayyam_i_ha = $date_hash->{month} == -1 ? 1 : 0;

    if(!$args{size} && $args{numeric} && $args{alpha}) {
        # short alpha-numeric
        $date .= sprintf '%s (%d), %s (%d) of %s (%d), year %d, %s (%d) of %s (%d)',
            @$date_hash{qw(
                dow_name dow day_name day month_name month
                year year_name cycle_year cycle_name cycle
            )};
    }
    elsif($args{size} && $args{numeric} && $args{alpha}) {
        # long alpha-numeric
        # XXX Fugly hacking begins.
        my $month_string = $is_ayyam_i_ha ? '%s%s' : 'the %s month %s';
        my $n = year2en($date_hash->{year});

        $date .= sprintf
            "%s week day %s, %s day %s of $month_string, year %s (%d), %s year %s of the %s vahid %s of the %s kull-i-shay",
            num2en_ordinal($date_hash->{dow}),
            $date_hash->{dow_name},
            num2en_ordinal($date_hash->{day}),
            $date_hash->{day_name},
            ($is_ayyam_i_ha ? '' : num2en_ordinal($date_hash->{month})),
            $date_hash->{month_name},
            $n,
            $date_hash->{year},
            num2en_ordinal($date_hash->{cycle_year}),
            $date_hash->{year_name},
            num2en_ordinal($date_hash->{cycle}),
            $date_hash->{cycle_name},
            num2en_ordinal($date_hash->{kull_i_shay});
    }
    elsif(!$args{size} && $args{numeric}) {
        # short numeric
        $date .= sprintf '%s/%s/%s', @$date_hash{qw(month day year)};
    }
    elsif($args{size} && $args{numeric}) {
        # long numeric
        $date .= sprintf
            '%s day of the week, %s day of the %s month, year %s, %s year of the %s vahid of the %s kull-i-shay',
            num2en_ordinal($date_hash->{dow}),
            num2en_ordinal($date_hash->{day}),
            num2en_ordinal($date_hash->{month}),
            $date_hash->{year},
            num2en_ordinal($date_hash->{cycle_year}),
            num2en_ordinal($date_hash->{cycle}),
            num2en_ordinal($date_hash->{kull_i_shay});
    }
    elsif(!$args{size} && $args{alpha}) {
        # short alpha
        $date .= sprintf '%s, %s of %s, %s of %s',
            @$date_hash{qw(
                dow_name day_name month_name year_name cycle_name
            )};
    }
    else {
        # long alpha
        my $month_string = $is_ayyam_i_ha ? '%s' : 'month %s';
        my $n = year2en($date_hash->{year});

        $date .= sprintf
            "week day %s, day %s of $month_string, year %s, %s of the vahid %s of the %s kull-i-shay",
            @$date_hash{qw(dow_name day_name month_name)},
            $n,
            @$date_hash{qw(year_name cycle_name)},
            num2en_ordinal($date_hash->{kull_i_shay});
    }

    if($date_hash->{holy_day} && $args{size}) {
        $date .= ', holy day: ' . join '', keys %{ $date_hash->{holy_day} };
    }

    return $date;
}

sub next_holy_day {
    my($year, $month, $day) = @_;

    # Use today if we are not provided with a date.
    ($year, $month, $day) = _ymd(
        year  => $year,
        month => $month,
        day   => $day,
    );

    # Construct our lists of pseudo real number dates.
    my %inverted = _invert_holy_days($year);
    my @sorted = sort { $a <=> $b } keys %inverted;

    # Make the month and day a pseudo real number.
    my $m_d = "$month.$day";
    my $holy_date;

    # Find the first date greater than the one provided.
    for(@sorted) {
        if($m_d < $_) {
            $holy_date = $_;
            last;
        }
    }

    # If one was not found, grab the last date in the list.
    $holy_date = $sorted[-1] unless $holy_date;

    # Make this look like a date again.
    (my $date = $holy_date) =~ s/\./\//;

    return wantarray
        ? ($inverted{$holy_date}, $date)
        : "$inverted{$holy_date} $date";
}

# Helper functions
# Date comparison gymnastics.
sub _setup_date_comparison {
    my($y, $m, $d, $s, $e) = @_;

    # Dates are encoded as decimals.
    my($start_month, $start_day) = split /\./, $s;
    my($end_month, $end_day) = split /\./, $e;

    # Slide either the start or end year, given the month we're
    # looking at.
    my($start_year, $end_year) = ($y, $y);
    if($end_month < $start_month) {
        if($m == $start_month) {
            $end_year++;
        }
        elsif($m == $end_month) {
            $start_year--;
        }
    }

    return
        Date_to_Days($y, $m, $d),
        Date_to_Days($start_year, $start_month, $start_day),
        Date_to_Days($end_year, $end_month, $end_day);
}

sub _build_date {
    my($year, $month, $day, $new_month, $new_day, %args) = @_;

    my %date;
    @date{qw(month day)} = ($new_month, $new_day);

    # Set the day of the week (rotated by 2).
    $date{dow} = Day_of_Week($year, $month, $day);
    $date{dow} += 2;
    $date{dow} = $date{dow} - 7 if $date{dow} > 7;
    $date{dow_name} = (DOW_NAME)[$date{dow} - 1];

    # Set the day.
    $date{day_name} = (MONTH_DAY)[$date{day}];
    $date{day}++;

    # Set the the month.
    $date{month_name} = (MONTH_DAY)[$date{month}];
    # Fix the month number, unless we are in Ayyam-i-Ha.
    $date{month}++ unless $date{month} == -1;

    # Set the year.
    # Algorithm lifted from Danesh's "bahaidate".
    $date{year} = ($month < MARCH) ||
        ($month == MARCH && $day < YEAR_START_DAY)
        ? $year - FIRST_YEAR
        : $year - (FIRST_YEAR - 1);

    $date{year_name} = (CYCLE_YEAR)[($date{year} - 1) % FACTOR];
    $date{cycle_year} = $date{year} % FACTOR;

    # Set the cycle.
    $date{cycle} = int($date{year} / FACTOR) + 1;
    $date{cycle_name} = (CYCLE_YEAR)[($date{cycle} - 1) % FACTOR];

    # Set the Kull-i-Shay.
    $date{kull_i_shay} = int($date{cycle} / FACTOR) + 1;

#    $date{timezone} = tz_local_offset();

    # Get the holy day.
    my %inverted = _invert_holy_days($year);
    my $m_d = sprintf '%d.%d', $month, $day;
    $date{holy_day} = $inverted{$m_d} if exists $inverted{$m_d};

    return wantarray ? %date : as_string(\%date, %args);
}

sub _invert_holy_days {
    my $year = shift || (localtime)[5] + ADJUST_YEAR;

    my %inverted;

    while(my($name, $date) = each %{ HOLY_DAYS() }) {
        $inverted{$date->[0]} = $name;

        # Does this date contain a day span?
        if(@$date > 1) {
            # Increment the Ayyam-i-Ha day if we are in a leap year.
            $date->[1]++ if $name eq 'Ayyam-i-Ha' && leap_year($year);

            for(1 .. $date->[1] - 1) {
                (undef, my $month, my $day) = Add_Delta_Days(
                    $year, split(/\./, $date->[0]), $_
                );

                # Pre-pad the day number with a zero.
                $inverted{ sprintf '%d.%d', $month, $day } = $name;
            }
        }
    }

    return %inverted;
}

# Return a ymd date array but try to honor the epoch and use_gmtime settings.
sub _ymd {
    my %args = @_;

    # Use the system time, if a ymd is not provided.
    unless($args{year} && $args{month} && $args{day}) {
        $args{epoch} ||= time;
        ($args{year}, $args{month}, $args{day}) = $args{use_gmtime}
            ? (gmtime $args{epoch})[5,4,3]
            : (localtime $args{epoch})[5,4,3];
        # Fix the year and the month.
        $args{year} += ADJUST_YEAR;
        $args{month}++;
    }

    return $args{year}, $args{month}, $args{day};
}

1;
__END__


1; # End of Date::Baha::i