In Files
- date.rb
- date/format.rb
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Date
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.
format.rb: Written by Tadayoshi Funaba 1999-2008 $Id: format.rb,v 2.43 2008-01-17 20:16:31+09 tadf Exp $
Constants
- ABBR_DAYNAMES
Abbreviated day names, in English.
- ABBR_MONTHNAMES
Abbreviated month names, in English.
- DAYNAMES
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.
- ENGLAND
The Julian Day Number of the Day of Calendar Reform for England and her Colonies.
- GREGORIAN
A constant used to indicate that a Date should always use the Gregorian calendar.
- ITALY
The Julian Day Number of the Day of Calendar Reform for Italy and the Catholic countries.
- JULIAN
A constant used to indicate that a Date should always use the Julian calendar.
- MONTHNAMES
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).
Public Instance Methods
alias_method :format, :strftime
# File date/format.rb, line 341
def asctime() strftime('%c') end
# File date/format.rb, line 215
def strftime(fmt='%F')
fmt.gsub(/%([-_0^#]+)?(\d+)?([EO]?(?::{1,3}z|.))/) do
f = {}
m = $&
s, w, c = $1, $2, $3
if s
s.scan(/./) do |k|
case k
when '-'; f[:p] = '-'
when '_'; f[:p] = "\s"
when '0'; f[:p] = '0'
when '^'; f[:u] = true
when '#'; f[:x] = true
end
end
end
if w
f[:w] = w.to_i
end
case c
when 'A'; emit_ad(DAYNAMES[wday], 0, f)
when 'a'; emit_ad(ABBR_DAYNAMES[wday], 0, f)
when 'B'; emit_ad(MONTHNAMES[mon], 0, f)
when 'b'; emit_ad(ABBR_MONTHNAMES[mon], 0, f)
when 'C', 'EC'; emit_sn((year / 100).floor, 2, f)
when 'c', 'Ec'; emit_a(strftime('%a %b %e %H:%M:%S %Y'), 0, f)
when 'D'; emit_a(strftime('%m/%d/%y'), 0, f)
when 'd', 'Od'; emit_n(mday, 2, f)
when 'e', 'Oe'; emit_a(mday, 2, f)
when 'F'
if m == '%F'
format('%.4d-%02d-%02d', year, mon, mday) # 4p
else
emit_a(strftime('%Y-%m-%d'), 0, f)
end
when 'G'; emit_sn(cwyear, 4, f)
when 'g'; emit_n(cwyear % 100, 2, f)
when 'H', 'OH'; emit_n(hour, 2, f)
when 'h'; emit_ad(strftime('%b'), 0, f)
when 'I', 'OI'; emit_n((hour % 12).nonzero? || 12, 2, f)
when 'j'; emit_n(yday, 3, f)
when 'k'; emit_a(hour, 2, f)
when 'L'
f[:p] = nil
w = f[:w] || 3
u = 10**w
emit_n((sec_fraction * u).floor, w, f)
when 'l'; emit_a((hour % 12).nonzero? || 12, 2, f)
when 'M', 'OM'; emit_n(min, 2, f)
when 'm', 'Om'; emit_n(mon, 2, f)
when 'N'
f[:p] = nil
w = f[:w] || 9
u = 10**w
emit_n((sec_fraction * u).floor, w, f)
when 'n'; emit_a("\n", 0, f)
when 'P'; emit_ad(strftime('%p').downcase, 0, f)
when 'p'; emit_au(if hour < 12 then 'AM' else 'PM' end, 0, f)
when 'Q'
s = ((ajd - UNIX_EPOCH_IN_AJD) / MILLISECONDS_IN_DAY).round
emit_sn(s, 1, f)
when 'R'; emit_a(strftime('%H:%M'), 0, f)
when 'r'; emit_a(strftime('%I:%M:%S %p'), 0, f)
when 'S', 'OS'; emit_n(sec, 2, f)
when 's'
s = ((ajd - UNIX_EPOCH_IN_AJD) / SECONDS_IN_DAY).round
emit_sn(s, 1, f)
when 'T'
if m == '%T'
format('%02d:%02d:%02d', hour, min, sec) # 4p
else
emit_a(strftime('%H:%M:%S'), 0, f)
end
when 't'; emit_a("\t", 0, f)
when 'U', 'W', 'OU', 'OW'
emit_n(if c[-1,1] == 'U' then wnum0 else wnum1 end, 2, f)
when 'u', 'Ou'; emit_n(cwday, 1, f)
when 'V', 'OV'; emit_n(cweek, 2, f)
when 'v'; emit_a(strftime('%e-%b-%Y'), 0, f)
when 'w', 'Ow'; emit_n(wday, 1, f)
when 'X', 'EX'; emit_a(strftime('%H:%M:%S'), 0, f)
when 'x', 'Ex'; emit_a(strftime('%m/%d/%y'), 0, f)
when 'Y', 'EY'; emit_sn(year, 4, f)
when 'y', 'Ey', 'Oy'; emit_n(year % 100, 2, f)
when 'Z'; emit_au(strftime('%:z'), 0, f)
when /\A(:{0,3})z/
t = $1.size
sign = if offset < 0 then -1 else +1 end
fr = offset.abs
ss = fr.div(SECONDS_IN_DAY) # 4p
hh, ss = ss.divmod(3600)
mm, ss = ss.divmod(60)
if t == 3
if ss.nonzero? then t = 2
elsif mm.nonzero? then t = 1
else t = -1
end
end
case t
when -1
tail = []
sep = ''
when 0
f[:w] -= 2 if f[:w]
tail = ['%02d' % mm]
sep = ''
when 1
f[:w] -= 3 if f[:w]
tail = ['%02d' % mm]
sep = ':'
when 2
f[:w] -= 6 if f[:w]
tail = ['%02d' % mm, '%02d' % ss]
sep = ':'
end
([emit_z(sign * hh, 2, f)] + tail).join(sep)
when '%'; emit_a('%', 0, f)
when '+'; emit_a(strftime('%a %b %e %H:%M:%S %Z %Y'), 0, f)
else
m
end
end
end
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