Module:Date
Documentation for this module may be created at Module:Date/doc
-- Date functions for implementing templates and for use by other modules. -- I18N and time zones are not supported. local MINUS = '−' -- Unicode U+2212 MINUS SIGN local function collection() -- Return a table to hold items. return { n = 0, add = function (self, item) self.n = self.n + 1 self[self.n] = item end, join = function (self, sep) return table.concat(self, sep) end, } end local function strip_to_nil(text) -- Return nil if text is nil or is an empty string after trimming. -- If text is a non-blank string, return its content after trimming. -- Otherwise return text (convenient when accessed via another module). if type(text) == 'string' then local result = text:match("^%s*(.-)%s*$") if result == '' then return nil end return result end if text == nil then return nil end return text end local function number_name(number, singular, plural, sep) -- Return the given number, converted to a string, with the -- separator (default space) and singular or plural name appended. plural = plural or (singular .. 's') sep = sep or ' ' return tostring(number) .. sep .. ((number == 1) and singular or plural) end local function is_leap_year(year, calname) -- Return true if year is a leap year. if calname == 'Julian' then return year % 4 == 0 end return (year % 4 == 0 and year % 100 ~= 0) or year % 400 == 0 end local function days_in_month(year, month, calname) -- Return number of days (1..31) in given month (1..12). local month_days = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 } if month == 2 and is_leap_year(year, calname) then return 29 end return month_days[month] end local function julian_date(date) -- Return jd, jdz from a Julian or Gregorian calendar date where -- jd = Julian date and its fractional part is zero at noon -- jdz = similar, but fractional part is zero at 00:00:00 -- http://www.tondering.dk/claus/cal/julperiod.php#formula -- Testing shows this works for all dates from year -9999 to 9999! -- JDN 0 is the 24-hour period starting at noon UTC on Monday -- 1 January 4713 BC = (-4712, 1, 1) Julian calendar -- 24 November 4714 BC = (-4713, 11, 24) Gregorian calendar if not date.isvalid then return 0, 0 -- always return numbers to simplify usage end local floor = math.floor local offset local a = floor((14 - date.month)/12) local y = date.year + 4800 - a if date.calname == 'Julian' then offset = floor(y/4) - 32083 else offset = floor(y/4) - floor(y/100) + floor(y/400) - 32045 end local m = date.month + 12*a - 3 local date_part = date.day + floor((153*m + 2)/5) + 365*y + offset local time_part, zbias if date.hastime then time_part = (date.hour + (date.minute + date.second / 60) /60) / 24 - 0.5 zbias = 0 else time_part = 0 zbias = -0.5 end local jd = date_part + time_part return jd, jd + zbias end local function set_date_from_jd(date) -- Set the fields of table date from its Julian date field. -- http://www.tondering.dk/claus/cal/julperiod.php#formula -- This handles the proleptic Julian and Gregorian calendars. -- Negative Julian dates are not defined but they work. local floor = math.floor local calname = date.calname local jd = date.jd local limits -- min/max limits for date ranges −9999-01-01 to 9999-12-31 if calname == 'Julian' then limits = { -1931076.5, 5373557.49999 } elseif calname == 'Gregorian' then limits = { -1930999.5, 5373484.49999 } else limits = { 1, 0 } -- impossible end if not (limits[1] <= jd and jd <= limits[2]) then date.isvalid = false return end date.isvalid = true local jdn = floor(jd) if date.hastime then local time = jd - jdn local hour if time >= 0.5 then jdn = jdn + 1 time = time - 0.5 hour = 0 else hour = 12 end time = floor(time * 24 * 3600 + 0.5) -- number of seconds after hour date.second = time % 60 time = floor(time / 60) date.minute = time % 60 date.hour = hour + floor(time / 60) else date.second = 0 date.minute = 0 date.hour = 0 end local b, c if calname == 'Julian' then b = 0 c = jdn + 32082 else -- Gregorian local a = jdn + 32044 b = floor((4*a + 3)/146097) c = a - floor(146097*b/4) end local d = floor((4*c + 3)/1461) local e = c - floor(1461*d/4) local m = floor((5*e + 2)/153) date.day = e - floor((153*m + 2)/5) + 1 date.month = m + 3 - 12*floor(m/10) date.year = 100*b + d - 4800 + floor(m/10) end local function set_date_from_numbers(date, numbers, options) -- Set the fields of table date from numeric values. -- Return true if date is valid. if type(numbers) ~= 'table' then return end local y = numbers.y or numbers[1] local m = numbers.m or numbers[2] local d = numbers.d or numbers[3] local H = numbers.H or numbers[4] local M = numbers.M or numbers[5] or 0 local S = numbers.S or numbers[6] or 0 if not (y and m and d) then return end if not (-9999 <= y and y <= 9999 and 1 <= m and m <= 12 and 1 <= d and d <= days_in_month(y, m, date.calname)) then return end if H then date.hastime = true else H = 0 end if not (0 <= H and H <= 23 and 0 <= M and M <= 59 and 0 <= S and S <= 59) then return end date.year = y -- -9999 to 9999 ('n BC' → year = 1 - n) date.month = m -- 1 to 12 date.day = d -- 1 to 31 date.hour = H -- 0 to 59 date.minute = M -- 0 to 59 date.second = S -- 0 to 59 date.isvalid = true if type(options) == 'table' then for _, k in ipairs({ 'am', 'era' }) do if options[k] then date.options[k] = options[k] end end end return true end local function make_option_table(options) -- If options is a string, return a table with its settings. -- Otherwise return options (it should already be a table). if type(options) == 'string' then -- Example: 'am:AM era:BC' local result = {} for item in options:gmatch('%S+') do local lhs, rhs = item:match('^(%w+):(.*)$') if lhs then result[lhs] = rhs end end return result end return options end local function strftime(date, format, options) -- Return date formatted as a string using codes similar to those -- in the C strftime library function. if not date.isvalid then return '(invalid)' end local shortcuts = { ['%c'] = '%-I:%M %p %-d %B %Y%{era}', -- date and time: 2:30 pm 1 April 2016 ['%x'] = '%-d %B %Y%{era}', -- date: 1 April 2016 ['%X'] = '%-I:%M %p', -- time: 2:30 pm } local codes = { a = { field = 'dayabbr' }, A = { field = 'dayname' }, b = { field = 'monthabbr' }, B = { field = 'monthname' }, u = { fmt = '%d' , field = 'dowiso' }, w = { fmt = '%d' , field = 'dow' }, d = { fmt = '%02d', fmt2 = '%d', field = 'day' }, m = { fmt = '%02d', fmt2 = '%d', field = 'month' }, Y = { fmt = '%04d', fmt2 = '%d', field = 'year' }, H = { fmt = '%02d', fmt2 = '%d', field = 'hour' }, M = { fmt = '%02d', fmt2 = '%d', field = 'minute' }, S = { fmt = '%02d', fmt2 = '%d', field = 'second' }, j = { fmt = '%03d', fmt2 = '%d', field = 'doy' }, I = { fmt = '%02d', fmt2 = '%d', field = 'hour', special = 'hour12' }, p = { field = 'hour', special = 'am' }, } options = make_option_table(options or date.options) local amopt = options.am local eraopt = options.era local function replace_code(modifier, id) local code = codes[id] if code then local fmt = code.fmt if modifier == '-' and code.fmt2 then fmt = code.fmt2 end local value = date[code.field] local special = code.special if special then if special == 'hour12' then value = value % 12 value = value == 0 and 12 or value elseif special == 'am' then local ap = ({ ['a.m.'] = { 'a.m.', 'p.m.' }, ['AM'] = { 'AM', 'PM' }, ['A.M.'] = { 'A.M.', 'P.M.' }, })[amopt] or { 'am', 'pm' } return value < 12 and ap[1] or ap[2] end end if code.field == 'year' then if eraopt == 'BCMINUS' or eraopt == 'BCNEGATIVE' then local sign if value >= 0 then sign = '' else sign = eraopt == 'BCMINUS' and MINUS or '-' value = -value end return sign .. string.format(fmt, value) end if value <= 0 then value = 1 - value end end return fmt and string.format(fmt, value) or value end end local function replace_property(id) local result = date[id] if type(result) == 'string' then if id == 'era' and result ~= '' then -- Assume era follows a date. return ' ' .. result end return result end if type(result) == 'number' then return tostring(result) end if type(result) == 'boolean' then return result and '1' or '0' end -- This occurs, for example, if id is the name of a function. return nil end if shortcuts[format] then format = shortcuts[format] end local PERCENT = '\127PERCENT\127' return (format :gsub('%%%%', PERCENT) :gsub('%%{(%w+)}', replace_property) :gsub('%%(-?)(%a)', replace_code) :gsub(PERCENT, '%%') ) end local function date_text(date, fmt, options) -- Return formatted string from given date. if not (type(date) == 'table' and date.isvalid) then return '(invalid)' end if type(fmt) ~= 'string' then fmt = '%Y-%m-%d' if date.hastime then if date.second > 0 then fmt = fmt .. ' %H:%M:%S' else fmt = fmt .. ' %H:%M' end end return strftime(date, fmt, options or { era = 'BCMINUS' }) end if fmt:find('%', 1, true) then return strftime(date, fmt, options) end local t = collection() for item in fmt:gmatch('%S+') do local f if item == 'hm' then f = '%H:%M' elseif item == 'hms' then f = '%H:%M:%S' elseif item == 'ymd' then f = '%Y:%m:%d%{era}' elseif item == 'mdy' then f = '%B %-d, %Y%{era}' elseif item == 'dmy' then f = '%-d %B %Y%{era}' else return '(invalid format)' end t:add(f) end return strftime(date, t:join(' '), options) end local day_info = { -- 0=Sun to 6=Sat [0] = { 'Sun', 'Sunday' }, { 'Mon', 'Monday' }, { 'Tue', 'Tuesday' }, { 'Wed', 'Wednesday' }, { 'Thu', 'Thursday' }, { 'Fri', 'Friday' }, { 'Sat', 'Saturday' }, } local month_info = { -- 1=Jan to 12=Dec { 'Jan', 'January' }, { 'Feb', 'February' }, { 'Mar', 'March' }, { 'Apr', 'April' }, { 'May', 'May' }, { 'Jun', 'June' }, { 'Jul', 'July' }, { 'Aug', 'August' }, { 'Sep', 'September' }, { 'Oct', 'October' }, { 'Nov', 'November' }, { 'Dec', 'December' }, } local function month_number(text) if type(text) == 'string' then local month_names = { jan = 1, january = 1, feb = 2, february = 2, mar = 3, march = 3, apr = 4, april = 4, may = 5, jun = 6, june = 6, jul = 7, july = 7, aug = 8, august = 8, sep = 9, september = 9, oct = 10, october = 10, nov = 11, november = 11, dec = 12, december = 12 } return month_names[text:lower()] end end -- A table to get the current year/month/day (UTC), but only if needed. local current = setmetatable({}, { __index = function (self, key) local d = os.date('!*t') self.year = d.year self.month = d.month self.day = d.day self.hour = d.hour self.minute = d.min self.second = d.sec return rawget(self, key) end }) local function date_component(named, positional, component) -- Return the first of the two arguments (named like {{example|year=2001}} -- or positional like {{example|2001}}) that is not nil and is not empty. -- If both are nil, return the current date component, if specified. -- This translates empty arguments passed to the template to nil, and -- optionally replaces a nil argument with a value from the current date. named = strip_to_nil(named) if named then return named end positional = strip_to_nil(positional) if positional then return positional end if component then return current[component] end return nil end local era_text = { -- options.era = { year<0 , year>0 } ['BCMINUS'] = { MINUS , '' }, ['BCNEGATIVE'] = { '-' , '' }, ['BC'] = { 'BC' , '' }, ['B.C.'] = { 'B.C.' , '' }, ['BCE'] = { 'BCE' , '' }, ['B.C.E.'] = { 'B.C.E.', '' }, ['AD'] = { 'BC' , 'AD' }, ['A.D.'] = { 'B.C.' , 'A.D.' }, ['CE'] = { 'BCE' , 'CE' }, ['C.E.'] = { 'B.C.E.', 'C.E.' }, } local function extract_date(text) -- Parse the date/time in text and return n, o where -- n = table of numbers with date/time fields -- o = table of options for AM/PM or AD/BC, if any -- or return nothing if date is known to be invalid. -- Caller determines if the values in n are valid. -- Dates of form d/m/y, m/d/y, y/m/d are rejected as ambiguous and undesirable. local date, options = {}, {} local function extract_ymd(item) local ystr, mstr, dstr = item:match('^(%d%d%d%d)-(%w+)-(%d%d?)$') if ystr then local m if mstr:match('^%d%d?$') then m = tonumber(mstr) else m = month_number(mstr) end if m then date.y = tonumber(ystr) date.m = m date.d = tonumber(dstr) return true end end end local function extract_month(item) -- A month must be given as a name or abbreviation; a number would be ambiguous. local m = month_number(item) if m then date.m = m return true end end local function extract_time(item) local h, m, s = item:match('^(%d%d?):(%d%d)(:?%d*)$') if date.H or not h then return end if s ~= '' then s = s:match('^:(%d%d)$') if not s then return end end date.H = tonumber(h) date.M = tonumber(m) date.S = tonumber(s) -- nil if empty string return true end local ampm_options = { ['am'] = 'am', ['AM'] = 'AM', ['a.m.'] = 'a.m.', ['A.M.'] = 'A.M.', ['pm'] = 'am', -- same as am ['PM'] = 'AM', ['p.m.'] = 'a.m.', ['P.M.'] = 'A.M.', } local item_count = 0 local index_time local function set_ampm(item) local H = date.H if H and not options.am and index_time + 1 == item_count then options.am = ampm_options[item] if item:match('^[Aa]') then if not (1 <= H and H <= 12) then return end if H == 12 then date.H = 0 end else if not (1 <= H and H <= 23) then return end if H <= 11 then date.H = H + 12 end end return true end end for item in text:gsub(',', ' '):gmatch('%S+') do -- Accept options in peculiar places; if duplicated, last wins. item_count = item_count + 1 if era_text[item] then options.era = item elseif ampm_options[item] then if not set_ampm(item) then return end elseif item:find(':', 1, true) then if not extract_time(item) then return end index_time = item_count elseif date.d and date.m then if date.y then return -- should be nothing more so item is invalid end if not item:match('^(%d%d?%d?%d?)$') then return end date.y = tonumber(item) elseif date.d then if not extract_month(item) then return end elseif date.m then if not item:match('^(%d%d?)$') then return end date.d = tonumber(item) elseif not extract_ymd(item) then if item:match('^(%d%d?)$') then date.d = tonumber(item) elseif not extract_month(item) then return end end end return date, options end -- Metatable for some operations on dates. -- For Lua 5.1, __lt does not work if the metatable is an anonymous table. local Date -- forward declaration local datemt = { __eq = function (lhs, rhs) -- Return true if dates identify same date/time where, for example, -- (-4712, 1, 1, 'Julian') == (-4713, 11, 24, 'Gregorian'). return lhs.isvalid and rhs.isvalid and lhs.jdz == rhs.jdz end, __lt = function (lhs, rhs) -- Return true if lhs < rhs. if not lhs.isvalid then return true end if not rhs.isvalid then return false end return lhs.jdz < rhs.jdz end, __index = function (self, key) local value if key == 'dayabbr' then value = day_info[self.dow][1] elseif key == 'dayname' then value = day_info[self.dow][2] elseif key == 'dow' then value = (self.jd + 1) % 7 -- day-of-week 0=Sun to 6=Sat elseif key == 'dowiso' then value = (self.jd % 7) + 1 -- ISO day-of-week 1=Mon to 7=Sun elseif key == 'doy' then local first = Date(self.year, 1, 1, self.calname).jd value = self.jd - first + 1 -- day-of-year 1 to 366 elseif key == 'era' then -- Era text from year and options. local eraopt = self.options.era local sign if self.year == 0 then sign = (eraopt == 'BCMINUS' or eraopt == 'BCNEGATIVE') and 2 or 1 else sign = self.year > 0 and 2 or 1 end value = era_text[eraopt][sign] elseif key == 'gsd' then -- GSD = 1 from 00:00:00 to 23:59:59 on 1 January 1 AD Gregorian calendar, -- which is JDN = 1721426, and is from jd 1721425.5 to 1721426.49999. value = math.floor(self.jd - 1721424.5) elseif key == 'jd' or key == 'jdz' then local jd, jdz = julian_date(self) rawset(self, 'jd', jd) rawset(self, 'jdz', jdz) return key == 'jd' and jd or jdz elseif key == 'is_leap_year' then value = is_leap_year(self.year, self.calname) elseif key == 'monthabbr' then value = month_info[self.month][1] elseif key == 'monthname' then value = month_info[self.month][2] end if value ~= nil then rawset(self, key, value) return value end end, } --[[ Examples of syntax to construct a date: Date(y, m, d, 'julian') default calendar is 'gregorian' Date(y, m, d, H, M, S, 'julian') Date('juliandate', jd, 'julian') if jd contains "." text output includes H:M:S Date('currentdate') Date('currentdatetime') LATER: Following are not yet implemented: Date('currentdate', H, M, S) current date with given time Date('1 April 1995', 'julian') parse date from text Date('1 April 1995 AD', 'julian') AD, CE, BC, BCE (using one of these sets a flag to do same for output) Date('04:30:59 1 April 1995', 'julian') ]] function Date(...) -- for forward declaration above -- Return a table to hold a date assuming a uniform calendar always applies (proleptic). -- If invalid, return an empty table which is regarded as invalid. local calendars = { julian = 'Julian', gregorian = 'Gregorian' } local result = { isvalid = false, -- false avoids __index lookup calname = 'Gregorian', -- default is Gregorian calendar hastime = false, -- true if input sets a time hour = 0, -- always set hour/minute/second so don't have to handle nil minute = 0, second = 0, month_days = function (self, month) return days_in_month(self.year, month, self.calname) end, -- Valid option settings are: -- am: 'am', 'a.m.', 'AM', 'A.M.' -- era: 'BCMINUS', 'BCNEGATIVE', 'BC', 'B.C.', 'BCE', 'B.C.E.', 'AD', 'A.D.', 'CE', 'C.E.' options = { am = 'am', era = 'BC' }, text = date_text, } local argtype, datetext local numbers = collection() for _, v in ipairs({...}) do v = strip_to_nil(v) local vlower = type(v) == 'string' and v:lower() or nil if v == nil then -- Ignore empty arguments after stripping so modules can directly pass template parameters. elseif calendars[vlower] then result.calname = calendars[vlower] else local num = tonumber(v) if not num and argtype == 'setdate' and numbers.n == 1 then num = month_number(v) end if num then if not argtype then argtype = 'setdate' end numbers:add(num) if argtype == 'juliandate' then if type(v) == 'string' then if v:find('.', 1, true) then result.hastime = true end elseif num ~= math.floor(num) then -- The given value was a number. The time will be used -- if the fractional part is nonzero. result.hastime = true end end elseif argtype then return {} elseif type(v) == 'string' then if v == 'currentdate' or v == 'currentdatetime' or v == 'juliandate' then argtype = v else argtype = 'datetext' datetext = v end else return {} end end end if argtype == 'datetext' then if not (numbers.n == 0 and set_date_from_numbers(result, extract_date(datetext))) then return {} end elseif argtype == 'juliandate' then if numbers.n == 1 then result.jd = numbers[1] set_date_from_jd(result) else return {} end elseif argtype == 'currentdate' or argtype == 'currentdatetime' then result.year = current.year result.month = current.month result.day = current.day if argtype == 'currentdatetime' then result.hour = current.hour result.minute = current.minute result.second = current.second result.hastime = true end result.calname = 'Gregorian' -- ignore any given calendar name result.isvalid = true elseif argtype == 'setdate' then if not set_date_from_numbers(result, numbers) then return {} end else return {} end return setmetatable(result, datemt) end local function DateDiff(date1, date2) -- Return a table to with the difference between the two given dates. -- Difference is negative if the second date is older than the first. -- TODO Replace with something using Julian dates? -- Who checks for isvalid()? -- Handle calname == 'Julian' local calname = 'Gregorian' -- TODO fix local isnegative if date2 < date1 then isnegative = true date1, date2 = date2, date1 end -- It is known that date1 <= date2. local y1, m1 = date1.year, date1.month local y2, m2 = date2.year, date2.month local years, months, days = y2 - y1, m2 - m1, date2.day - date1.day if days < 0 then days = days + days_in_month(y1, m1, calname) months = months - 1 end if months < 0 then months = months + 12 years = years - 1 end return { years = years, months = months, days = days, isnegative = isnegative, age_ym = function (self) -- Return text specifying difference in years, months. local sign = self.isnegative and MINUS or '' local mtext = number_name(self.months, 'month') local result if self.years > 0 then local ytext = number_name(self.years, 'year') if self.months == 0 then result = ytext else result = ytext .. ', ' .. mtext end else if self.months == 0 then sign = '' end result = mtext end return sign .. result end, } end local function message(msg, nocat) -- Return formatted message text for an error. -- Can append "#FormattingError" to URL of a page with a problem to find it. local anchor = '<span id="FormattingError" />' local category if not nocat and mw.title.getCurrentTitle():inNamespaces(0, 10) then -- Category only in namespaces: 0=article, 10=template. category = '[[Category:Age error]]' else category = '' end return anchor .. '<strong class="error">Error: ' .. msg .. '</strong>' .. category .. '\n' end local function age_days(frame) -- Return age in days between two given dates, or -- between given date and current date. -- This code implements the logic in [[Template:Age in days]]. -- Like {{Age in days}}, a missing argument is replaced from the current -- date, so can get a bizarre mixture of specified/current y/m/d. local args = frame:getParent().args local date1 = Date( date_component(args.year1 , args[1], 'year' ), date_component(args.month1, args[2], 'month'), date_component(args.day1 , args[3], 'day' ) ) local date2 = Date( date_component(args.year2 , args[4], 'year' ), date_component(args.month2, args[5], 'month'), date_component(args.day2 , args[6], 'day' ) ) if not (date1.isvalid and date2.isvalid) then return message('Need valid year, month, day') end local sign = '' local result = date2.jd - date1.jd if result < 0 then sign = MINUS result = -result end return sign .. tostring(result) end local function age_ym(frame) -- Return age in years and months between two given dates, or -- between given date and current date. local args = frame:getParent().args local fields = {} for i = 1, 6 do fields[i] = strip_to_nil(args[i]) end local date1, date2 if fields[1] and fields[2] and fields[3] then date1 = Date(fields[1], fields[2], fields[3]) end if not (date1 and date1.isvalid) then return message('Need valid year, month, day') end if fields[4] and fields[5] and fields[6] then date2 = Date(fields[4], fields[5], fields[6]) if not date2.isvalid then return message('Second date should be year, month, day') end else date2 = Date('currentdate') end return DateDiff(date1, date2):age_ym() end local function gsd_ymd(frame) -- Return Gregorian serial date of the given date, or the current date. -- Like {{Gregorian serial date}}, a missing argument is replaced from the -- current date, so can get a bizarre mixture of specified/current y/m/d. -- This also accepts positional arguments, although the original template does not. -- The returned value is negative for dates before 1 January 1 AD despite -- the fact that GSD is not defined for earlier dates. local args = frame:getParent().args local date = Date( date_component(args.year , args[1], 'year' ), date_component(args.month, args[2], 'month'), date_component(args.day , args[3], 'day' ) ) if date.isvalid then return tostring(date.gsd) end return message('Need valid year, month, day') end local function ymd_from_jd(frame) -- Return formatted date from a Julian date. -- The result is y-m-d or y-m-d H:M:S if input includes a fraction. -- The word 'Julian' is accepted for the Julian calendar. local args = frame:getParent().args local date = Date('juliandate', args[1], args[2]) if date.isvalid then return date:text() end return message('Need valid Julian date number') end local function ymd_to_jd(frame) -- Return Julian date (a number) from a date (y-m-d), or datetime (y-m-d H:M:S), -- or the current date ('currentdate') or current datetime ('currentdatetime'). -- The word 'Julian' is accepted for the Julian calendar. local args = frame:getParent().args local date = Date(args[1], args[2], args[3], args[4], args[5], args[6], args[7]) if date.isvalid then return tostring(date.jd) end return message('Need valid year/month/day or "currentdate"') end return { age_days = age_days, age_ym = age_ym, _Date = Date, days_in_month = days_in_month, gsd = gsd_ymd, JULIANDAY = ymd_to_jd, ymd_from_jd = ymd_from_jd, ymd_to_jd = ymd_to_jd, }