Class Date
In: lib/date.rb
Parent: Object

Class representing a date.

See the documentation to the file date.rb for an overview.

Internally, the date is represented as an Astronomical Julian Day Number, ajd. The Day of Calendar Reform, sg, is also stored, for conversions to other date formats. (There is also an of field for a time zone offset, but this is only for the use of the DateTime subclass.)

A new Date object is created using one of the object creation class methods named after the corresponding date format, and the arguments appropriate to that date format; for instance, Date::civil() (aliased to Date::new()) with year, month, and day-of-month, or Date::ordinal() with year and day-of-year. All of these object creation class methods also take the Day of Calendar Reform as an optional argument.

Date objects are immutable once created.

Once a Date has been created, date values can be retrieved for the different date formats supported using instance methods. For instance, mon() gives the Civil month, cwday() gives the Commercial day of the week, and yday() gives the Ordinal day of the year. Date values can be retrieved in any format, regardless of what format was used to create the Date instance.

The Date class includes the Comparable module, allowing date objects to be compared and sorted, ranges of dates to be created, and so forth.

Methods

+   -   <<   <=>   ===   >>   _dump   _load   ajd   ajd_to_amjd   ajd_to_jd   amjd   amjd_to_ajd   civil   civil_to_jd   commercial   commercial_to_jd   cwday   cweek   cwyear   day   day_fraction   day_fraction_to_time   downto   england   eql?   gregorian   gregorian?   gregorian?   gregorian_leap?   hash   inspect   italy   jd   jd   jd_to_ajd   jd_to_civil   jd_to_commercial   jd_to_ld   jd_to_mjd   jd_to_ordinal   jd_to_wday   julian   julian?   julian?   julian_leap?   ld   ld_to_jd   leap?   mday   mjd   mjd_to_jd   mon   month   new   new_start   next   ordinal   ordinal_to_jd   parse   start   step   strptime   succ   time_to_day_fraction   time_to_day_fraction   to_s   today   upto   valid_civil?   valid_commercial?   valid_jd?   valid_ordinal?   valid_time?   wday   yday   year  

Included Modules

Comparable

Constants

MONTHNAMES = [nil] + %w(January February March April May June July August September October November December)   Full month names, in English. Months count from 1 to 12; a month‘s numerical representation indexed into this array gives the name of that month (hence the first element is nil).
DAYNAMES = %w(Sunday Monday Tuesday Wednesday Thursday Friday Saturday)   Full names of days of the week, in English. Days of the week count from 0 to 6 (except in the commercial week); a day‘s numerical representation indexed into this array gives the name of that day.
ABBR_MONTHNAMES = [nil] + %w(Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec)   Abbreviated month names, in English.
ABBR_DAYNAMES = %w(Sun Mon Tue Wed Thu Fri Sat)   Abbreviated day names, in English.
ITALY = 2299161   The Julian Day Number of the Day of Calendar Reform for Italy and the Catholic countries.
ENGLAND = 2361222   The Julian Day Number of the Day of Calendar Reform for England and her Colonies.
JULIAN = Infinity.new   A constant used to indicate that a Date should always use the Julian calendar.
GREGORIAN = -Infinity.new   A constant used to indicate that a Date should always use the Gregorian calendar.

External Aliases

gregorian_leap? -> leap?
new -> new!
valid_civil? -> valid_date?
civil -> new

Public Class methods

Load from Marshal format.

[Source]

# File lib/date.rb, line 1389
  def self._load(str)
    a = Marshal.load(str)
    if a.size == 2
      ajd,     sg = a
           of = 0
      ajd -= 1.to_r/2
    else
      ajd, of, sg = a
    end
    new!(ajd, of, sg)
  end

Convert an Astronomical Julian Day Number to an Astronomical Modified Julian Day Number.

[Source]

# File lib/date.rb, line 538
  def self.ajd_to_amjd(ajd) ajd - MJD_EPOCH_IN_AJD end

Convert an Astronomical Julian Day Number to a (civil) Julian Day Number.

ajd is the Astronomical Julian Day Number to convert. of is the offset from UTC as a fraction of a day (defaults to 0).

Returns the (civil) Julian Day Number as [day_number, fraction] where fraction is always 1/2.

[Source]

# File lib/date.rb, line 492
  def self.ajd_to_jd(ajd, of=0) (ajd + of + HALF_DAYS_IN_DAY).divmod(1) end

Convert an Astronomical Modified Julian Day Number to an Astronomical Julian Day Number.

[Source]

# File lib/date.rb, line 534
  def self.amjd_to_ajd(amjd) amjd + MJD_EPOCH_IN_AJD end

Create a new Date object for the Civil Date specified by year y, month m, and day-of-month d.

m and d can be negative, in which case they count backwards from the end of the year and the end of the month respectively. No wraparound is performed, however, and invalid values cause an ArgumentError to be raised. can be negative

y defaults to -4712, m to 1, and d to 1; this is Julian Day Number day 0.

sg specifies the Day of Calendar Reform.

[Source]

# File lib/date.rb, line 750
  def self.civil(y=-4712, m=1, d=1, sg=ITALY)
    unless jd = valid_civil?(y, m, d, sg)
      raise ArgumentError, 'invalid date'
    end
    new!(jd_to_ajd(jd, 0, 0), 0, sg)
  end

Convert a Civil Date to a Julian Day Number. y, m, and d are the year, month, and day of the month. sg specifies the Day of Calendar Reform.

Returns the corresponding Julian Day Number.

[Source]

# File lib/date.rb, line 396
  def self.civil_to_jd(y, m, d, sg=GREGORIAN)
    if m <= 2
      y -= 1
      m += 12
    end
    a = (y / 100.0).floor
    b = 2 - a + (a / 4.0).floor
    jd = (365.25 * (y + 4716)).floor +
      (30.6001 * (m + 1)).floor +
      d + b - 1524
    if julian?(jd, sg)
      jd -= b
    end
    jd
  end

Create a new Date object for the Commercial Date specified by year y, week-of-year w, and day-of-week d.

Monday is day-of-week 1; Sunday is day-of-week 7.

w and d can be negative, in which case they count backwards from the end of the year and the end of the week respectively. No wraparound is performed, however, and invalid values cause an ArgumentError to be raised.

y defaults to 1582, w to 41, and d to 5, the Day of Calendar Reform for Italy and the Catholic countries.

sg specifies the Day of Calendar Reform.

[Source]

# File lib/date.rb, line 773
  def self.commercial(y=1582, w=41, d=5, sg=ITALY)
    unless jd = valid_commercial?(y, w, d, sg)
      raise ArgumentError, 'invalid date'
    end
    new!(jd_to_ajd(jd, 0, 0), 0, sg)
  end

Convert a Commercial Date to a Julian Day Number.

y, w, and d are the (commercial) year, week of the year, and day of the week of the Commercial Date to convert. sg specifies the Day of Calendar Reform.

[Source]

# File lib/date.rb, line 445
  def self.commercial_to_jd(y, w, d, ns=GREGORIAN)
    jd = civil_to_jd(y, 1, 4, ns)
    (jd - (((jd - 1) + 1) % 7)) +
      7 * (w - 1) +
      (d - 1)
  end

Convert a fractional day fr to [hours, minutes, seconds, fraction_of_a_second]

[Source]

# File lib/date.rb, line 507
  def self.day_fraction_to_time(fr)
    ss,  fr = fr.divmod(SECONDS_IN_DAY) # 4p
    h,   ss = ss.divmod(3600)
    min, s  = ss.divmod(60)
    return h, min, s, fr
  end

Does a given Julian Day Number fall inside the new-style (Gregorian) calendar?

The reverse of self.os? See the documentation for that method for more details.

[Source]

# File lib/date.rb, line 358
  def self.gregorian? (jd, sg) !julian?(jd, sg) end

Is a year a leap year in the Gregorian calendar?

All years divisible by 4 are leap years in the Gregorian calendar, except for years divisible by 100 and not by 400.

[Source]

# File lib/date.rb, line 570
  def self.gregorian_leap? (y) y % 4 == 0 && y % 100 != 0 || y % 400 == 0 end

Create a new Date object from a Julian Day Number.

jd is the Julian Day Number; if not specified, it defaults to 0. sg specifies the Day of Calendar Reform.

[Source]

# File lib/date.rb, line 715
  def self.jd(jd=0, sg=ITALY)
    jd = valid_jd?(jd, sg)
    new!(jd_to_ajd(jd, 0, 0), 0, sg)
  end

Convert a (civil) Julian Day Number to an Astronomical Julian Day Number.

jd is the Julian Day Number to convert, and fr is a fractional day. of is the offset from UTC as a fraction of a day (defaults to 0).

Returns the Astronomical Julian Day Number as a single numeric value.

[Source]

# File lib/date.rb, line 503
  def self.jd_to_ajd(jd, fr, of=0) jd + fr - of - HALF_DAYS_IN_DAY end

Convert a Julian Day Number to a Civil Date. jd is the Julian Day Number. sg specifies the Day of Calendar Reform.

Returns the corresponding [year, month, day_of_month] as a three-element array.

[Source]

# File lib/date.rb, line 418
  def self.jd_to_civil(jd, sg=GREGORIAN)
    if julian?(jd, sg)
      a = jd
    else
      x = ((jd - 1867216.25) / 36524.25).floor
      a = jd + 1 + x - (x / 4.0).floor
    end
    b = a + 1524
    c = ((b - 122.1) / 365.25).floor
    d = (365.25 * c).floor
    e = ((b - d) / 30.6001).floor
    dom = b - d - (30.6001 * e).floor
    if e <= 13
      m = e - 1
      y = c - 4716
    else
      m = e - 13
      y = c - 4715
    end
    return y, m, dom
  end

Convert a Julian Day Number to a Commercial Date

jd is the Julian Day Number to convert. sg specifies the Day of Calendar Reform.

Returns the corresponding Commercial Date as [commercial_year, week_of_year, day_of_week]

[Source]

# File lib/date.rb, line 459
  def self.jd_to_commercial(jd, sg=GREGORIAN)
    ns = fix_style(jd, sg)
    a = jd_to_civil(jd - 3, ns)[0]
    y = if jd >= commercial_to_jd(a + 1, 1, 1, ns) then a + 1 else a end
    w = 1 + ((jd - commercial_to_jd(y, 1, 1, ns)) / 7).floor
    d = (jd + 1) % 7
    d = 7 if d == 0
    return y, w, d
  end

Convert a Julian Day Number to the number of days since the adoption of the Gregorian Calendar (in Italy).

[Source]

# File lib/date.rb, line 554
  def self.jd_to_ld(jd) jd - LD_EPOCH_IN_CJD end

Convert a Julian Day Number to a Modified Julian Day Number.

[Source]

# File lib/date.rb, line 546
  def self.jd_to_mjd(jd) jd - MJD_EPOCH_IN_CJD end

Convert a Julian Day Number to an Ordinal Date.

jd is the Julian Day Number to convert. sg specifies the Day of Calendar Reform.

Returns the corresponding Ordinal Date as [year, day_of_year]

[Source]

# File lib/date.rb, line 385
  def self.jd_to_ordinal(jd, sg=GREGORIAN)
    y = jd_to_civil(jd, sg)[0]
    doy = jd - civil_to_jd(y - 1, 12, 31, fix_style(jd, sg))
    return y, doy
  end

Convert a Julian Day Number to the day of the week.

Sunday is day-of-week 0; Saturday is day-of-week 6.

[Source]

# File lib/date.rb, line 559
  def self.jd_to_wday(jd) (jd + 1) % 7 end

Does a given Julian Day Number fall inside the old-style (Julian) calendar?

jd is the Julian Day Number in question. sg may be Date::GREGORIAN, in which case the answer is false; it may be Date::JULIAN, in which case the answer is true; or it may a number representing the Day of Calendar Reform. Date::ENGLAND and Date::ITALY are two possible such days.

[Source]

# File lib/date.rb, line 340
  def self.julian? (jd, sg)
    case sg
    when Numeric
      jd < sg
    else
      if $VERBOSE
        warn("#{caller.shift.sub(/:in .*/, '')}: " \
"warning: do not use non-numerical object as julian day number anymore")
      end
      not sg
    end
  end

Is a year a leap year in the Julian calendar?

All years divisible by 4 are leap years in the Julian calendar.

[Source]

# File lib/date.rb, line 564
  def self.julian_leap? (y) y % 4 == 0 end

Convert a count of the number of days since the adoption of the Gregorian Calendar (in Italy) to a Julian Day Number.

[Source]

# File lib/date.rb, line 550
  def self.ld_to_jd(ld) ld + LD_EPOCH_IN_CJD end

Convert a Modified Julian Day Number to a Julian Day Number.

[Source]

# File lib/date.rb, line 542
  def self.mjd_to_jd(mjd) mjd + MJD_EPOCH_IN_CJD end

NOTE this is the documentation for the method new!(). If you are reading this as the documentation for new(), that is because rdoc doesn‘t fully support the aliasing of the initialize() method. new() is in fact an alias for civil(): read the documentation for that method instead.

Create a new Date object.

ajd is the Astronomical Julian Day Number. of is the offset from UTC as a fraction of a day. Both default to 0.

sg specifies the Day of Calendar Reform to use for this Date object.

Using one of the factory methods such as Date::civil is generally easier and safer.

[Source]

# File lib/date.rb, line 1041
  def initialize(ajd=0, of=0, sg=ITALY) @ajd, @of, @sg = ajd, of, sg end

Create a new Date object from an Ordinal Date, specified by year y and day-of-year d. d can be negative, in which it counts backwards from the end of the year. No year wraparound is performed, however. An invalid value for d results in an ArgumentError being raised.

y defaults to -4712, and d to 1; this is Julian Day Number day 0.

sg specifies the Day of Calendar Reform.

[Source]

# File lib/date.rb, line 730
  def self.ordinal(y=-4712, d=1, sg=ITALY)
    unless jd = valid_ordinal?(y, d, sg)
      raise ArgumentError, 'invalid date'
    end
    new!(jd_to_ajd(jd, 0, 0), 0, sg)
  end

Convert an Ordinal Date to a Julian Day Number.

y and d are the year and day-of-year to convert. sg specifies the Day of Calendar Reform.

Returns the corresponding Julian Day Number.

[Source]

# File lib/date.rb, line 374
  def self.ordinal_to_jd(y, d, sg=GREGORIAN)
    civil_to_jd(y, 1, d, sg)
  end

Create a new Date object by parsing from a String, without specifying the format.

str is a String holding a date representation. comp specifies whether to interpret 2-digit years as 19XX (>= 69) or 20XX (< 69); the default is not to. The method will attempt to parse a date from the String using various heuristics; see _parse in date/format.rb for more details. If parsing fails, an ArgumentError will be raised.

The default str is ’-4712-01-01’; this is Julian Day Number day 0.

sg specifies the Day of Calendar Reform.

[Source]

# File lib/date.rb, line 998
  def self.parse(str='-4712-01-01', comp=false, sg=ITALY)
    elem = _parse(str, comp)
    new_by_frags(elem, sg)
  end

Create a new Date object by parsing from a String according to a specified format.

str is a String holding a date representation. fmt is the format that the date is in. See date/format.rb for details on supported formats.

The default str is ’-4712-01-01’, and the default fmt is ’%F’, which means Year-Month-Day_of_Month. This gives Julian Day Number day 0.

sg specifies the Day of Calendar Reform.

An ArgumentError will be raised if str cannot be parsed.

[Source]

# File lib/date.rb, line 978
  def self.strptime(str='-4712-01-01', fmt='%F', sg=ITALY)
    elem = _strptime(str, fmt)
    new_by_frags(elem, sg)
  end

[Source]

# File lib/date.rb, line 519
    def self.time_to_day_fraction(h, min, s)
      Rational(h * 3600 + min * 60 + s, 86400) # 4p
    end

[Source]

# File lib/date.rb, line 523
    def self.time_to_day_fraction(h, min, s)
        if Integer === h && Integer === min && Integer === s
          Rational(h * 3600 + min * 60 + s, 86400) # 4p
        else
          (h * 3600 + min * 60 + s).to_r/86400 # 4p
        end
    end

Create a new Date object representing today.

sg specifies the Day of Calendar Reform.

[Source]

# File lib/date.rb, line 1664
  def self.today(sg=ITALY) Time.now.__send__(:to_date)    .new_start(sg) end

Do year y, month m, and day-of-month d make a valid Civil Date? Returns the corresponding Julian Day Number if they do, nil if they don‘t.

m and d can be negative, in which case they count backwards from the end of the year and the end of the month respectively. No wraparound is performed, however, and invalid values cause an ArgumentError to be raised. A date falling in the period skipped in the Day of Calendar Reform adjustment is not valid.

sg specifies the Day of Calendar Reform.

[Source]

# File lib/date.rb, line 620
  def self.valid_civil? (y, m, d, sg=ITALY)
    if m < 0
      m += 13
    end
    if d < 0
      ny, nm = (y * 12 + m).divmod(12)
      nm,    = (nm + 1).divmod(1)
      jd = civil_to_jd(ny, nm, d + 1, sg)
      ns = fix_style(jd, sg)
      return unless [y, m] == jd_to_civil(jd, sg)[0..1]
      return unless [ny, nm, 1] == jd_to_civil(jd - d, ns)
    else
      jd = civil_to_jd(y, m, d, sg)
      return unless [y, m, d] == jd_to_civil(jd, sg)
    end
    jd
  end

Do year y, week-of-year w, and day-of-week d make a valid Commercial Date? Returns the corresponding Julian Day Number if they do, nil if they don‘t.

Monday is day-of-week 1; Sunday is day-of-week 7.

w and d can be negative, in which case they count backwards from the end of the year and the end of the week respectively. No wraparound is performed, however, and invalid values cause an ArgumentError to be raised. A date falling in the period skipped in the Day of Calendar Reform adjustment is not valid.

sg specifies the Day of Calendar Reform.

[Source]

# File lib/date.rb, line 654
  def self.valid_commercial? (y, w, d, sg=ITALY)
    if d < 0
      d += 8
    end
    if w < 0
      ny, nw, nd =
        jd_to_commercial(commercial_to_jd(y + 1, 1, 1) + w * 7)
      return unless ny == y
      w = nw
    end
    jd = commercial_to_jd(y, w, d)
    return unless gregorian?(jd, sg)
    return unless [y, w, d] == jd_to_commercial(jd)
    jd
  end

Is jd a valid Julian Day Number?

If it is, returns it. In fact, any value is treated as a valid Julian Day Number.

[Source]

# File lib/date.rb, line 579
  def self.valid_jd? (jd, sg=ITALY) jd end

Do the year y and day-of-year d make a valid Ordinal Date? Returns the corresponding Julian Day Number if they do, or nil if they don‘t.

d can be a negative number, in which case it counts backwards from the end of the year (-1 being the last day of the year). No year wraparound is performed, however, so valid values of d are -365 .. -1, 1 .. 365 on a non-leap-year, -366 .. -1, 1 .. 366 on a leap year. A date falling in the period skipped in the Day of Calendar Reform adjustment is not valid.

sg specifies the Day of Calendar Reform.

[Source]

# File lib/date.rb, line 594
  def self.valid_ordinal? (y, d, sg=ITALY)
    if d < 0
      ny, = (y + 1).divmod(1)
      jd = ordinal_to_jd(ny, d + 1, sg)
      ns = fix_style(jd, sg)
      return unless [y] == jd_to_ordinal(jd, sg)[0..0]
      return unless [ny, 1] == jd_to_ordinal(jd - d, ns)
    else
      jd = ordinal_to_jd(y, d, sg)
      return unless [y, d] == jd_to_ordinal(jd, sg)
    end
    jd
  end

Do hour h, minute min, and second s constitute a valid time?

If they do, returns their value as a fraction of a day. If not, returns nil.

The 24-hour clock is used. Negative values of h, min, and sec are treating as counting backwards from the end of the next larger unit (e.g. a min of -2 is treated as 58). No wraparound is performed.

[Source]

# File lib/date.rb, line 697
  def self.valid_time? (h, min, s)
    h   += 24 if h   < 0
    min += 60 if min < 0
    s   += 60 if s   < 0
    return unless ((0...24) === h &&
                   (0...60) === min &&
                   (0...60) === s) ||
                  (24 == h &&
                    0 == min &&
                    0 == s)
    time_to_day_fraction(h, min, s)
  end

Public Instance methods

Return a new Date object that is n days later than the current one.

n may be a negative value, in which case the new Date is earlier than the current one; however, #-() might be more intuitive.

If n is not a Numeric, a TypeError will be thrown. In particular, two Dates cannot be added to each other.

[Source]

# File lib/date.rb, line 1233
  def + (n)
    case n
    when Numeric; return self.class.new!(@ajd + n, @of, @sg)
    end
    raise TypeError, 'expected numeric'
  end

If x is a Numeric value, create a new Date object that is x days earlier than the current one.

If x is a Date, return the number of days between the two dates; or, more precisely, how many days later the current date is than x.

If x is neither Numeric nor a Date, a TypeError is raised.

[Source]

# File lib/date.rb, line 1248
  def - (x)
    case x
    when Numeric; return self.class.new!(@ajd - x, @of, @sg)
    when Date;    return @ajd - x.ajd
    end
    raise TypeError, 'expected numeric or date'
  end

Return a new Date object that is n months earlier than the current one.

If the day-of-the-month of the current Date is greater than the last day of the target month, the day-of-the-month of the returned Date will be the last day of the target month.

[Source]

# File lib/date.rb, line 1319
  def << (n) self >> -n end

Compare this date with another date.

other can also be a Numeric value, in which case it is interpreted as an Astronomical Julian Day Number.

Comparison is by Astronomical Julian Day Number, including fractional days. This means that both the time and the timezone offset are taken into account when comparing two DateTime instances. When comparing a DateTime instance with a Date instance, the time of the latter will be considered as falling on midnight UTC.

[Source]

# File lib/date.rb, line 1267
  def <=> (other)
    case other
    when Numeric; return @ajd <=> other
    when Date;    return @ajd <=> other.ajd
    end
    nil
  end

The relationship operator for Date.

Compares dates by Julian Day Number. When comparing two DateTime instances, or a DateTime with a Date, the instances will be regarded as equivalent if they fall on the same date in local time.

[Source]

# File lib/date.rb, line 1281
  def === (other)
    case other
    when Numeric; return jd == other
    when Date;    return jd == other.jd
    end
    false
  end

Return a new Date object that is n months later than the current one.

If the day-of-the-month of the current Date is greater than the last day of the target month, the day-of-the-month of the returned Date will be the last day of the target month.

[Source]

# File lib/date.rb, line 1305
  def >> (n)
    y, m = (year * 12 + (mon - 1) + n).divmod(12)
    m,   = (m + 1)                    .divmod(1)
    d = mday
    d -= 1 until jd2 = self.class.valid_civil?(y, m, d, fix_style)
    self + (jd2 - jd)
  end

Dump to Marshal format.

[Source]

# File lib/date.rb, line 1384
  def _dump(limit) Marshal.dump([@ajd, @of, @sg], -1) end

Get the date as an Astronomical Julian Day Number.

[Source]

# File lib/date.rb, line 1044
  def ajd() @ajd end

Get the date as an Astronomical Modified Julian Day Number.

[Source]

# File lib/date.rb, line 1047
  def amjd() self.class.ajd_to_amjd(@ajd) end

Get the commercial day of the week of this date. Monday is commercial day-of-week 1; Sunday is commercial day-of-week 7.

[Source]

# File lib/date.rb, line 1147
  def cwday() commercial[2] end

Get the commercial week of the year of this date.

[Source]

# File lib/date.rb, line 1143
  def cweek() commercial[1] end

Get the commercial year of this date. See Commercial Date in the introduction for how this differs from the normal year.

[Source]

# File lib/date.rb, line 1140
  def cwyear() commercial[0] end
day()

Alias for mday

Get any fractional day part of the date.

[Source]

# File lib/date.rb, line 1055
  def day_fraction() self.class.ajd_to_jd(@ajd, @of)[1] end

Step backward one day at a time until we reach min (inclusive), yielding each date as we go.

[Source]

# File lib/date.rb, line 1363
  def downto(min, &block) # :yield: date
    step(min, -1, &block)
  end

Create a copy of this Date object that uses the English/Colonial Day of Calendar Reform.

[Source]

# File lib/date.rb, line 1203
  def england() new_start(self.class::ENGLAND) end

Is this Date equal to other?

other must both be a Date object, and represent the same date.

[Source]

# File lib/date.rb, line 1370
  def eql? (other) Date === other && self == other end

Create a copy of this Date object that always uses the Gregorian Calendar.

[Source]

# File lib/date.rb, line 1211
  def gregorian() new_start(self.class::GREGORIAN) end

Is the current date new-style (Gregorian Calendar)?

[Source]

# File lib/date.rb, line 1171
  def gregorian? () self.class.gregorian?(jd, @sg) end

Calculate a hash value for this date.

[Source]

# File lib/date.rb, line 1373
  def hash() @ajd.hash end

Return internal object state as a programmer-readable string.

[Source]

# File lib/date.rb, line 1376
  def inspect() format('#<%s: %s,%s,%s>', self.class, @ajd, @of, @sg) end

Create a copy of this Date object that uses the Italian/Catholic Day of Calendar Reform.

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# File lib/date.rb, line 1199
  def italy() new_start(self.class::ITALY) end

Get the date as a Julian Day Number.

[Source]

# File lib/date.rb, line 1052
  def jd() self.class.ajd_to_jd(@ajd, @of)[0] end

Create a copy of this Date object that always uses the Julian Calendar.

[Source]

# File lib/date.rb, line 1207
  def julian() new_start(self.class::JULIAN) end

Is the current date old-style (Julian Calendar)?

[Source]

# File lib/date.rb, line 1168
  def julian? () self.class.julian?(jd, @sg) end

Get the date as the number of days since the Day of Calendar Reform (in Italy and the Catholic countries).

[Source]

# File lib/date.rb, line 1062
  def ld() self.class.jd_to_ld(jd) end

Is this a leap year?

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# File lib/date.rb, line 1184
  def leap?
    self.class.jd_to_civil(self.class.civil_to_jd(year, 3, 1, fix_style) - 1,
                     fix_style)[-1] == 29
  end

Get the day-of-the-month of this date.

[Source]

# File lib/date.rb, line 1095
  def mday() civil[2] end

Get the date as a Modified Julian Day Number.

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# File lib/date.rb, line 1058
  def mjd() self.class.jd_to_mjd(jd) end

Get the month of this date.

January is month 1.

[Source]

# File lib/date.rb, line 1092
  def mon() civil[1] end
month()

Alias for mon

Create a copy of this Date object using a new Day of Calendar Reform.

[Source]

# File lib/date.rb, line 1195
  def new_start(sg=self.class::ITALY) self.class.new!(@ajd, @of, sg) end

Return a new Date one day after this one.

[Source]

# File lib/date.rb, line 1295
  def next() next_day end

When is the Day of Calendar Reform for this Date object?

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# File lib/date.rb, line 1192
  def start() @sg end

Step the current date forward step days at a time (or backward, if step is negative) until we reach limit (inclusive), yielding the resultant date at each step.

[Source]

# File lib/date.rb, line 1335
  def step(limit, step=1) # :yield: date
??
??
    da = self
    op = %w(- <= >=)[step <=> 0]
    while da.__send__(op, limit)
      yield da
      da += step
    end
    self
  end
succ()

Alias for next

Return the date as a human-readable string.

The format used is YYYY-MM-DD.

[Source]

# File lib/date.rb, line 1381
  def to_s() format('%.4d-%02d-%02d', year, mon, mday) end

Step forward one day at a time until we reach max (inclusive), yielding each date as we go.

[Source]

# File lib/date.rb, line 1357
  def upto(max, &block) # :yield: date
    step(max, +1, &block)
  end

Get the week day of this date. Sunday is day-of-week 0; Saturday is day-of-week 6.

[Source]

# File lib/date.rb, line 1151
  def wday() self.class.jd_to_wday(jd) end

Get the day-of-the-year of this date.

January 1 is day-of-the-year 1

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# File lib/date.rb, line 1087
  def yday() ordinal[1] end

Get the year of this date.

[Source]

# File lib/date.rb, line 1082
  def year() civil[0] end

[Validate]