# <!-- rdoc-file=ext/date/date_core.c -->
# ## DateTime
#
# A subclass of Date that easily handles date, hour, minute, second, and offset.
#
# DateTime class is considered deprecated. Use Time class.
#
# DateTime does not consider any leap seconds, does not track any summer time
# rules.
#
# A DateTime object is created with DateTime::new, DateTime::jd,
# DateTime::ordinal, DateTime::commercial, DateTime::parse, DateTime::strptime,
# DateTime::now, Time#to_datetime, etc.
#
#     require 'date'
#
#     DateTime.new(2001,2,3,4,5,6)
#                         #=> #<DateTime: 2001-02-03T04:05:06+00:00 ...>
#
# The last element of day, hour, minute, or second can be a fractional number.
# The fractional number's precision is assumed at most nanosecond.
#
#     DateTime.new(2001,2,3.5)
#                         #=> #<DateTime: 2001-02-03T12:00:00+00:00 ...>
#
# An optional argument, the offset, indicates the difference between the local
# time and UTC. For example, `Rational(3,24)` represents ahead of 3 hours of
# UTC, `Rational(-5,24)` represents behind of 5 hours of UTC. The offset should
# be -1 to +1, and its precision is assumed at most second. The default value is
# zero (equals to UTC).
#
#     DateTime.new(2001,2,3,4,5,6,Rational(3,24))
#                         #=> #<DateTime: 2001-02-03T04:05:06+03:00 ...>
#
# The offset also accepts string form:
#
#     DateTime.new(2001,2,3,4,5,6,'+03:00')
#                         #=> #<DateTime: 2001-02-03T04:05:06+03:00 ...>
#
# An optional argument, the day of calendar reform (`start`), denotes a Julian
# day number, which should be 2298874 to 2426355 or negative/positive infinity.
# The default value is `Date::ITALY` (2299161=1582-10-15).
#
# A DateTime object has various methods. See each reference.
#
#     d = DateTime.parse('3rd Feb 2001 04:05:06+03:30')
#                         #=> #<DateTime: 2001-02-03T04:05:06+03:30 ...>
#     d.hour              #=> 4
#     d.min               #=> 5
#     d.sec               #=> 6
#     d.offset            #=> (7/48)
#     d.zone              #=> "+03:30"
#     d += Rational('1.5')
#                         #=> #<DateTime: 2001-02-04%16:05:06+03:30 ...>
#     d = d.new_offset('+09:00')
#                         #=> #<DateTime: 2001-02-04%21:35:06+09:00 ...>
#     d.strftime('%I:%M:%S %p')
#                         #=> "09:35:06 PM"
#     d > DateTime.new(1999)
#                         #=> true
#
# ### When should you use DateTime and when should you use Time?
#
# It's a common misconception that [William
# Shakespeare](https://en.wikipedia.org/wiki/William_Shakespeare) and [Miguel de
# Cervantes](https://en.wikipedia.org/wiki/Miguel_de_Cervantes) died on the same
# day in history - so much so that UNESCO named April 23 as [World Book Day
# because of this fact](https://en.wikipedia.org/wiki/World_Book_Day). However,
# because England hadn't yet adopted the [Gregorian Calendar
# Reform](https://en.wikipedia.org/wiki/Gregorian_calendar#Gregorian_reform)
# (and wouldn't until
# [1752](https://en.wikipedia.org/wiki/Calendar_(New_Style)_Act_1750)) their
# deaths are actually 10 days apart. Since Ruby's Time class implements a
# [proleptic Gregorian
# calendar](https://en.wikipedia.org/wiki/Proleptic_Gregorian_calendar) and has
# no concept of calendar reform there's no way to express this with Time
# objects. This is where DateTime steps in:
#
#     shakespeare = DateTime.iso8601('1616-04-23', Date::ENGLAND)
#      #=> Tue, 23 Apr 1616 00:00:00 +0000
#     cervantes = DateTime.iso8601('1616-04-23', Date::ITALY)
#      #=> Sat, 23 Apr 1616 00:00:00 +0000
#
# Already you can see something is weird - the days of the week are different.
# Taking this further:
#
#     cervantes == shakespeare
#      #=> false
#     (shakespeare - cervantes).to_i
#      #=> 10
#
# This shows that in fact they died 10 days apart (in reality 11 days since
# Cervantes died a day earlier but was buried on the 23rd). We can see the
# actual date of Shakespeare's death by using the #gregorian method to convert
# it:
#
#     shakespeare.gregorian
#      #=> Tue, 03 May 1616 00:00:00 +0000
#
# So there's an argument that all the celebrations that take place on the 23rd
# April in Stratford-upon-Avon are actually the wrong date since England is now
# using the Gregorian calendar. You can see why when we transition across the
# reform date boundary:
#
#     # start off with the anniversary of Shakespeare's birth in 1751
#     shakespeare = DateTime.iso8601('1751-04-23', Date::ENGLAND)
#      #=> Tue, 23 Apr 1751 00:00:00 +0000
#
#     # add 366 days since 1752 is a leap year and April 23 is after February 29
#     shakespeare + 366
#      #=> Thu, 23 Apr 1752 00:00:00 +0000
#
#     # add another 365 days to take us to the anniversary in 1753
#     shakespeare + 366 + 365
#      #=> Fri, 04 May 1753 00:00:00 +0000
#
# As you can see, if we're accurately tracking the number of [solar
# years](https://en.wikipedia.org/wiki/Tropical_year) since Shakespeare's
# birthday then the correct anniversary date would be the 4th May and not the
# 23rd April.
#
# So when should you use DateTime in Ruby and when should you use Time? Almost
# certainly you'll want to use Time since your app is probably dealing with
# current dates and times. However, if you need to deal with dates and times in
# a historical context you'll want to use DateTime to avoid making the same
# mistakes as UNESCO. If you also have to deal with timezones then best of luck
# - just bear in mind that you'll probably be dealing with [local solar
# times](https://en.wikipedia.org/wiki/Solar_time), since it wasn't until the
# 19th century that the introduction of the railways necessitated the need for
# [Standard Time](https://en.wikipedia.org/wiki/Standard_time#Great_Britain) and
# eventually timezones.
#
class DateTime < Date
  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - new(*args)
  # -->
  # Same as DateTime.new.
  #
  def initialize: (?Integer year, ?Integer month, ?Integer mday, ?Integer hour, ?Integer minute, ?Integer second, ?Integer offset, ?Integer start) -> void

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - DateTime._strptime(string[, format='%FT%T%z'])  ->  hash
  # -->
  # Parses the given representation of date and time with the given template, and
  # returns a hash of parsed elements.  _strptime does not support specification
  # of flags and width unlike strftime.
  #
  # See also strptime(3) and #strftime.
  #
  def self._strptime: (String str, ?String format) -> Hash[Symbol, Integer | String]

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - civil(*args)
  # -->
  # Same as DateTime.new.
  #
  def self.civil: (?Integer year, ?Integer month, ?Integer mday, ?Integer hour, ?Integer minute, ?Integer second, ?Integer offset, ?Integer start) -> DateTime

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - DateTime.commercial([cwyear=-4712[, cweek=1[, cwday=1[, hour=0[, minute=0[, second=0[, offset=0[, start=Date::ITALY]]]]]]]])  ->  datetime
  # -->
  # Creates a DateTime object denoting the given week date.
  #
  #     DateTime.commercial(2001) #=> #<DateTime: 2001-01-01T00:00:00+00:00 ...>
  #     DateTime.commercial(2002) #=> #<DateTime: 2001-12-31T00:00:00+00:00 ...>
  #     DateTime.commercial(2001,5,6,4,5,6,'+7')
  #                               #=> #<DateTime: 2001-02-03T04:05:06+07:00 ...>
  #
  def self.commercial: (?Integer cwyear, ?Integer cweek, ?Integer cwday, ?Integer hour, ?Integer minute, ?Integer second, ?Integer offset, ?Integer start) -> DateTime

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - DateTime.httpdate(string='Mon, 01 Jan -4712 00:00:00 GMT'[, start=Date::ITALY])  ->  datetime
  # -->
  # Creates a new DateTime object by parsing from a string according to some RFC
  # 2616 format.
  #
  #     DateTime.httpdate('Sat, 03 Feb 2001 04:05:06 GMT')
  #                               #=> #<DateTime: 2001-02-03T04:05:06+00:00 ...>
  #
  # Raise an ArgumentError when the string length is longer than *limit*. You can
  # stop this check by passing `limit: nil`, but note that it may take a long time
  # to parse.
  #
  def self.httpdate: (String str, ?Integer start) -> DateTime

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - DateTime.iso8601(string='-4712-01-01T00:00:00+00:00'[, start=Date::ITALY], limit: 128)  ->  datetime
  # -->
  # Creates a new DateTime object by parsing from a string according to some
  # typical ISO 8601 formats.
  #
  #     DateTime.iso8601('2001-02-03T04:05:06+07:00')
  #                               #=> #<DateTime: 2001-02-03T04:05:06+07:00 ...>
  #     DateTime.iso8601('20010203T040506+0700')
  #                               #=> #<DateTime: 2001-02-03T04:05:06+07:00 ...>
  #     DateTime.iso8601('2001-W05-6T04:05:06+07:00')
  #                               #=> #<DateTime: 2001-02-03T04:05:06+07:00 ...>
  #
  # Raise an ArgumentError when the string length is longer than *limit*. You can
  # stop this check by passing `limit: nil`, but note that it may take a long time
  # to parse.
  #
  def self.iso8601: (String str, ?Integer start) -> DateTime

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - DateTime.jd([jd=0[, hour=0[, minute=0[, second=0[, offset=0[, start=Date::ITALY]]]]]])  ->  datetime
  # -->
  # Creates a DateTime object denoting the given chronological Julian day number.
  #
  #     DateTime.jd(2451944)      #=> #<DateTime: 2001-02-03T00:00:00+00:00 ...>
  #     DateTime.jd(2451945)      #=> #<DateTime: 2001-02-04T00:00:00+00:00 ...>
  #     DateTime.jd(Rational('0.5'))
  #                               #=> #<DateTime: -4712-01-01T12:00:00+00:00 ...>
  #
  def self.jd: (?Integer jd, ?Integer hour, ?Integer minute, ?Integer second, ?Integer offset, ?Integer start) -> DateTime

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - DateTime.jisx0301(string='-4712-01-01T00:00:00+00:00'[, start=Date::ITALY], limit: 128)  ->  datetime
  # -->
  # Creates a new DateTime object by parsing from a string according to some
  # typical JIS X 0301 formats.
  #
  #     DateTime.jisx0301('H13.02.03T04:05:06+07:00')
  #                               #=> #<DateTime: 2001-02-03T04:05:06+07:00 ...>
  #
  # For no-era year, legacy format, Heisei is assumed.
  #
  #     DateTime.jisx0301('13.02.03T04:05:06+07:00')
  #                               #=> #<DateTime: 2001-02-03T04:05:06+07:00 ...>
  #
  # Raise an ArgumentError when the string length is longer than *limit*. You can
  # stop this check by passing `limit: nil`, but note that it may take a long time
  # to parse.
  #
  def self.jisx0301: (String str, ?Integer start) -> DateTime

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - DateTime.now([start=Date::ITALY])  ->  datetime
  # -->
  # Creates a DateTime object denoting the present time.
  #
  #     DateTime.now              #=> #<DateTime: 2011-06-11T21:20:44+09:00 ...>
  #
  def self.now: (?Integer start) -> DateTime

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - DateTime.ordinal([year=-4712[, yday=1[, hour=0[, minute=0[, second=0[, offset=0[, start=Date::ITALY]]]]]]])  ->  datetime
  # -->
  # Creates a DateTime object denoting the given ordinal date.
  #
  #     DateTime.ordinal(2001,34) #=> #<DateTime: 2001-02-03T00:00:00+00:00 ...>
  #     DateTime.ordinal(2001,34,4,5,6,'+7')
  #                               #=> #<DateTime: 2001-02-03T04:05:06+07:00 ...>
  #     DateTime.ordinal(2001,-332,-20,-55,-54,'+7')
  #                               #=> #<DateTime: 2001-02-03T04:05:06+07:00 ...>
  #
  def self.ordinal: (?Integer year, ?Integer yday, ?Integer hour, ?Integer minute, ?Integer second, ?Integer offset, ?Integer start) -> DateTime

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - DateTime.parse(string='-4712-01-01T00:00:00+00:00'[, comp=true[, start=Date::ITALY]], limit: 128)  ->  datetime
  # -->
  # Parses the given representation of date and time, and creates a DateTime
  # object.
  #
  # This method **does** **not** function as a validator.  If the input string
  # does not match valid formats strictly, you may get a cryptic result.  Should
  # consider to use DateTime.strptime instead of this method as possible.
  #
  # If the optional second argument is true and the detected year is in the range
  # "00" to "99", makes it full.
  #
  #     DateTime.parse('2001-02-03T04:05:06+07:00')
  #                               #=> #<DateTime: 2001-02-03T04:05:06+07:00 ...>
  #     DateTime.parse('20010203T040506+0700')
  #                               #=> #<DateTime: 2001-02-03T04:05:06+07:00 ...>
  #     DateTime.parse('3rd Feb 2001 04:05:06 PM')
  #                               #=> #<DateTime: 2001-02-03T16:05:06+00:00 ...>
  #
  # Raise an ArgumentError when the string length is longer than *limit*. You can
  # stop this check by passing `limit: nil`, but note that it may take a long time
  # to parse.
  #
  def self.parse: (String str, ?boolish complete, ?Integer start) -> DateTime

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - DateTime.rfc2822(string='Mon, 1 Jan -4712 00:00:00 +0000'[, start=Date::ITALY], limit: 128)  ->  datetime
  #   - DateTime.rfc822(string='Mon, 1 Jan -4712 00:00:00 +0000'[, start=Date::ITALY], limit: 128)   ->  datetime
  # -->
  # Creates a new DateTime object by parsing from a string according to some
  # typical RFC 2822 formats.
  #
  #     DateTime.rfc2822('Sat, 3 Feb 2001 04:05:06 +0700')
  #                              #=> #<DateTime: 2001-02-03T04:05:06+07:00 ...>
  #
  # Raise an ArgumentError when the string length is longer than *limit*. You can
  # stop this check by passing `limit: nil`, but note that it may take a long time
  # to parse.
  #
  def self.rfc2822: (String str, ?Integer start) -> DateTime

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - DateTime.rfc3339(string='-4712-01-01T00:00:00+00:00'[, start=Date::ITALY], limit: 128)  ->  datetime
  # -->
  # Creates a new DateTime object by parsing from a string according to some
  # typical RFC 3339 formats.
  #
  #     DateTime.rfc3339('2001-02-03T04:05:06+07:00')
  #                               #=> #<DateTime: 2001-02-03T04:05:06+07:00 ...>
  #
  # Raise an ArgumentError when the string length is longer than *limit*. You can
  # stop this check by passing `limit: nil`, but note that it may take a long time
  # to parse.
  #
  def self.rfc3339: (String str, ?Integer start) -> DateTime

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - DateTime.rfc2822(string='Mon, 1 Jan -4712 00:00:00 +0000'[, start=Date::ITALY], limit: 128)  ->  datetime
  #   - DateTime.rfc822(string='Mon, 1 Jan -4712 00:00:00 +0000'[, start=Date::ITALY], limit: 128)   ->  datetime
  # -->
  # Creates a new DateTime object by parsing from a string according to some
  # typical RFC 2822 formats.
  #
  #     DateTime.rfc2822('Sat, 3 Feb 2001 04:05:06 +0700')
  #                              #=> #<DateTime: 2001-02-03T04:05:06+07:00 ...>
  #
  # Raise an ArgumentError when the string length is longer than *limit*. You can
  # stop this check by passing `limit: nil`, but note that it may take a long time
  # to parse.
  #
  def self.rfc822: (String str, ?Integer start) -> DateTime

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - DateTime.strptime([string='-4712-01-01T00:00:00+00:00'[, format='%FT%T%z'[ ,start=Date::ITALY]]])  ->  datetime
  # -->
  # Parses the given representation of date and time with the given template, and
  # creates a DateTime object.  strptime does not support specification of flags
  # and width unlike strftime.
  #
  #     DateTime.strptime('2001-02-03T04:05:06+07:00', '%Y-%m-%dT%H:%M:%S%z')
  #                               #=> #<DateTime: 2001-02-03T04:05:06+07:00 ...>
  #     DateTime.strptime('03-02-2001 04:05:06 PM', '%d-%m-%Y %I:%M:%S %p')
  #                               #=> #<DateTime: 2001-02-03T16:05:06+00:00 ...>
  #     DateTime.strptime('2001-W05-6T04:05:06+07:00', '%G-W%V-%uT%H:%M:%S%z')
  #                               #=> #<DateTime: 2001-02-03T04:05:06+07:00 ...>
  #     DateTime.strptime('2001 04 6 04 05 06 +7', '%Y %U %w %H %M %S %z')
  #                               #=> #<DateTime: 2001-02-03T04:05:06+07:00 ...>
  #     DateTime.strptime('2001 05 6 04 05 06 +7', '%Y %W %u %H %M %S %z')
  #                               #=> #<DateTime: 2001-02-03T04:05:06+07:00 ...>
  #     DateTime.strptime('-1', '%s')
  #                               #=> #<DateTime: 1969-12-31T23:59:59+00:00 ...>
  #     DateTime.strptime('-1000', '%Q')
  #                               #=> #<DateTime: 1969-12-31T23:59:59+00:00 ...>
  #     DateTime.strptime('sat3feb014pm+7', '%a%d%b%y%H%p%z')
  #                               #=> #<DateTime: 2001-02-03T16:00:00+07:00 ...>
  #
  # See also strptime(3) and #strftime.
  #
  def self.strptime: (String str, ?String format, ?Integer start) -> DateTime

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - DateTime.xmlschema(string='-4712-01-01T00:00:00+00:00'[, start=Date::ITALY], limit: 128)  ->  datetime
  # -->
  # Creates a new DateTime object by parsing from a string according to some
  # typical XML Schema formats.
  #
  #     DateTime.xmlschema('2001-02-03T04:05:06+07:00')
  #                               #=> #<DateTime: 2001-02-03T04:05:06+07:00 ...>
  #
  # Raise an ArgumentError when the string length is longer than *limit*. You can
  # stop this check by passing `limit: nil`, but note that it may take a long time
  # to parse.
  #
  def self.xmlschema: (String str, ?Integer start) -> DateTime

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - deconstruct_keys(array_of_names_or_nil) -> hash
  # -->
  # Returns a hash of the name/value pairs, to use in pattern matching. Possible
  # keys are: `:year`, `:month`, `:day`, `:wday`, `:yday`, `:hour`, `:min`,
  # `:sec`, `:sec_fraction`, `:zone`.
  #
  # Possible usages:
  #
  #     dt = DateTime.new(2022, 10, 5, 13, 30)
  #
  #     if d in wday: 1..5, hour: 10..18  # uses deconstruct_keys underneath
  #       puts "Working time"
  #     end
  #     #=> prints "Working time"
  #
  #     case dt
  #     in year: ...2022
  #       puts "too old"
  #     in month: ..9
  #       puts "quarter 1-3"
  #     in wday: 1..5, month:
  #       puts "working day in month #{month}"
  #     end
  #     #=> prints "working day in month 10"
  #
  # Note that deconstruction by pattern can also be combined with class check:
  #
  #     if d in DateTime(wday: 1..5, hour: 10..18, day: ..7)
  #       puts "Working time, first week of the month"
  #     end
  #
  def deconstruct_keys: (Array[Symbol]?) -> Hash[Symbol, untyped]

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - hour -> integer
  # -->
  # Returns the hour in range (0..23):
  #
  #     DateTime.new(2001, 2, 3, 4, 5, 6).hour # => 4
  #
  def hour: () -> Integer

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - dt.iso8601([n=0])    ->  string
  #   - dt.xmlschema([n=0])  ->  string
  # -->
  # This method is equivalent to strftime('%FT%T%:z'). The optional argument `n`
  # is the number of digits for fractional seconds.
  #
  #     DateTime.parse('2001-02-03T04:05:06.123456789+07:00').iso8601(9)
  #                               #=> "2001-02-03T04:05:06.123456789+07:00"
  #
  def iso8601: (?Integer n) -> String

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - dt.jisx0301([n=0])  ->  string
  # -->
  # Returns a string in a JIS X 0301 format. The optional argument `n` is the
  # number of digits for fractional seconds.
  #
  #     DateTime.parse('2001-02-03T04:05:06.123456789+07:00').jisx0301(9)
  #                               #=> "H13.02.03T04:05:06.123456789+07:00"
  #
  def jisx0301: (?Integer n) -> String

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - min -> integer
  # -->
  # Returns the minute in range (0..59):
  #
  #     DateTime.new(2001, 2, 3, 4, 5, 6).min # => 5
  #
  def min: () -> Integer

  # <!-- rdoc-file=ext/date/date_core.c -->
  # Returns the minute in range (0..59):
  #
  #     DateTime.new(2001, 2, 3, 4, 5, 6).min # => 5
  #
  def minute: () -> Integer

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - d.new_offset([offset=0])  ->  date
  # -->
  # Duplicates self and resets its offset.
  #
  #     d = DateTime.new(2001,2,3,4,5,6,'-02:00')
  #                               #=> #<DateTime: 2001-02-03T04:05:06-02:00 ...>
  #     d.new_offset('+09:00')    #=> #<DateTime: 2001-02-03T15:05:06+09:00 ...>
  #
  def new_offset: (?String offset) -> DateTime

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - d.offset  ->  rational
  # -->
  # Returns the offset.
  #
  #     DateTime.parse('04pm+0730').offset        #=> (5/16)
  #
  def offset: () -> Rational

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - dt.rfc3339([n=0])  ->  string
  # -->
  # This method is equivalent to strftime('%FT%T%:z'). The optional argument `n`
  # is the number of digits for fractional seconds.
  #
  #     DateTime.parse('2001-02-03T04:05:06.123456789+07:00').rfc3339(9)
  #                               #=> "2001-02-03T04:05:06.123456789+07:00"
  #
  def rfc3339: (?Integer n) -> String

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - sec -> integer
  # -->
  # Returns the second in range (0..59):
  #
  #     DateTime.new(2001, 2, 3, 4, 5, 6).sec # => 6
  #
  def sec: () -> Integer

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - sec_fraction -> rational
  # -->
  # Returns the fractional part of the second in range (Rational(0,
  # 1)...Rational(1, 1)):
  #
  #     DateTime.new(2001, 2, 3, 4, 5, 6.5).sec_fraction # => (1/2)
  #
  def sec_fraction: () -> Rational

  # <!-- rdoc-file=ext/date/date_core.c -->
  # Returns the second in range (0..59):
  #
  #     DateTime.new(2001, 2, 3, 4, 5, 6).sec # => 6
  #
  def second: () -> Integer

  # <!-- rdoc-file=ext/date/date_core.c -->
  # Returns the fractional part of the second in range (Rational(0,
  # 1)...Rational(1, 1)):
  #
  #     DateTime.new(2001, 2, 3, 4, 5, 6.5).sec_fraction # => (1/2)
  #
  def second_fraction: () -> Rational

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - strftime(format = '%FT%T%:z') -> string
  # -->
  # Returns a string representation of `self`, formatted according the given
  # +format:
  #
  #     DateTime.now.strftime # => "2022-07-01T11:03:19-05:00"
  #
  # For other formats, see [Formats for Dates and
  # Times](rdoc-ref:strftime_formatting.rdoc):
  #
  def strftime: (?String format) -> String

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - dt.to_date  ->  date
  # -->
  # Returns a Date object which denotes self.
  #
  def to_date: () -> Date

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - dt.to_datetime  ->  self
  # -->
  # Returns self.
  #
  def to_datetime: () -> DateTime

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - dt.to_s  ->  string
  # -->
  # Returns a string in an ISO 8601 format. (This method doesn't use the expanded
  # representations.)
  #
  #     DateTime.new(2001,2,3,4,5,6,'-7').to_s
  #                              #=> "2001-02-03T04:05:06-07:00"
  #
  def to_s: () -> String

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - dt.to_time  ->  time
  # -->
  # Returns a Time object which denotes self.
  #
  def to_time: () -> Time

  # <!-- rdoc-file=ext/date/date_core.c -->
  # This method is equivalent to strftime('%FT%T%:z'). The optional argument `n`
  # is the number of digits for fractional seconds.
  #
  #     DateTime.parse('2001-02-03T04:05:06.123456789+07:00').iso8601(9)
  #                               #=> "2001-02-03T04:05:06.123456789+07:00"
  #
  def xmlschema: (?Integer n) -> String

  # <!--
  #   rdoc-file=ext/date/date_core.c
  #   - d.zone  ->  string
  # -->
  # Returns the timezone.
  #
  #     DateTime.parse('04pm+0730').zone          #=> "+07:30"
  #
  def zone: () -> String
end
