Module:Citation/CS1/Date validation

----< F O R W A R D  D E C L A R A T I O N S >--

local add_prop_cat, is_set, in_array, set_message, substitute, wrap_style;		-- imported functions from selected Module:Citation/CS1/Utilities local cfg;																		-- table of tables imported from selected Module:Citation/CS1/Configuration

--[[--< F I L E - S C O P E  D E C L A R A T I O N S >

File-scope variables are declared here

]]

local lang_object = mw.getContentLanguage;									-- used by is_valid_accessdate, is_valid_year, date_name_xlate; TODO: move to ~/Configuration? local year_limit;																-- used by is_valid_year

--[=[-< I S _ V A L I D _ A C C E S S D A T E >

returns true if: Wikipedia start date <= accessdate < today + 2 days

Wikipedia start date is 2001-01-15T00:00:00 UTC which is 979516800 seconds after 1970-01-01T00:00:00 UTC (the start of Unix time) accessdate is the date provided in |access-date= at time 00:00:00 UTC today is the current date at time 00:00:00 UTC plus 48 hours if today is 2015-01-01T00:00:00 then adding 24 hours gives 2015-01-02T00:00:00 – one second more than today adding 24 hours gives 2015-01-03T00:00:00 – one second more than tomorrow

This function does not work if it is fed month names for languages other than English. Wikimedia #time: parser apparently doesn't understand non-English date month names. This function will always return false when the date contains a non-English month name because good1 is false after the call to lang.formatDate. To get around that call this function with YYYY-MM-DD format dates.

]=]

local function is_valid_accessdate (accessdate) local good1, good2; local access_ts, tomorrow_ts;												-- to hold Unix time stamps representing the dates

good1, access_ts = pcall (lang_object.formatDate, lang_object, 'U', accessdate );			-- convert accessdate value to Unix timestamp good2, tomorrow_ts = pcall (lang_object.formatDate, lang_object, 'U', 'today + 2 days' );	-- today midnight + 2 days is one second more than all day tomorrow if good1 and good2 then														-- lang.formatDate returns a timestamp in the local script which which tonumber may not understand access_ts = tonumber (access_ts) or lang_object:parseFormattedNumber (access_ts);		-- convert to numbers for the comparison; tomorrow_ts = tonumber (tomorrow_ts) or lang_object:parseFormattedNumber (tomorrow_ts); else return false;															-- one or both failed to convert to Unix time stamp end

if 979516800 <= access_ts and access_ts < tomorrow_ts then					-- Wikipedia start date <= accessdate < tomorrow's date return true; else return false;															-- accessdate out of range end end

--[[--< G E T _ M O N T H _ N U M B E R >--

returns a number according to the month in a date: 1 for January, etc. Capitalization and spelling must be correct. If not a valid month, returns 0

]]

local function get_month_number (month) return cfg.date_names['local'].long[month] or cfg.date_names['local'].short[month] or	-- look for local names first cfg.date_names['en'].long[month] or	cfg.date_names['en'].short[month] or		-- failing that, look for English names 0;																				-- not a recognized month name end

--[[--< G E T _ S E A S O N _ N U M B E R >

returns a number according to the sequence of seasons in a year: 21 for Spring, etc. Capitalization and spelling must be correct. If not a valid season, returns 0. 21-24 = Spring, Summer, Autumn, Winter, independent of “Hemisphere”

returns 0 when is not |date=

Season numbering is defined by Extended Date/Time Format (EDTF) specification (https://www.loc.gov/standards/datetime/) which became part of ISO 8601 in 2019. See '§Sub-year groupings'. The standard defines various divisions using numbers 21-41. cs1|2 only supports generic seasons. EDTF does support the distinction between north and south hemisphere seasons but cs1|2 has no way to make that distinction.

These additional divisions not currently supported: 25-28 = Spring - Northern Hemisphere, Summer- Northern Hemisphere, Autumn - Northern Hemisphere, Winter - Northern Hemisphere 29-32 = Spring – Southern Hemisphere, Summer– Southern Hemisphere, Autumn – Southern Hemisphere, Winter - Southern Hemisphere 33-36 = Quarter 1, Quarter 2, Quarter 3, Quarter 4 (3 months each) 37-39 = Quadrimester 1, Quadrimester 2, Quadrimester 3 (4 months each) 40-41 = Semestral 1, Semestral-2 (6 months each)

]]

local function get_season_number (season, param) if 'date' ~= param then return 0;																-- season dates only supported by |date= end return cfg.date_names['local'].season[season] or							-- look for local names first cfg.date_names['en'].season[season] or								-- failing that, look for English names 0;																	-- not a recognized season name end

--[[--< G E T _ Q U A R T E R _ N U M B E R >--

returns a number according to the sequence of quarters in a year: 33 for first quarter, etc. Capitalization and spelling must be correct. If not a valid quarter, returns 0. 33-36 = Quarter 1, Quarter 2, Quarter 3, Quarter 4 (3 months each)

returns 0 when is not |date=

Quarter numbering is defined by Extended Date/Time Format (EDTF) specification (https://www.loc.gov/standards/datetime/) which became part of ISO 8601 in 2019. See '§Sub-year groupings'. The standard defines various divisions using numbers 21-41. cs1|2 only supports generic seasons and quarters.

These additional divisions not currently supported: 37-39 = Quadrimester 1, Quadrimester 2, Quadrimester 3 (4 months each) 40-41 = Semestral 1, Semestral-2 (6 months each)

]]

local function get_quarter_number (quarter, param) if 'date' ~= param then return 0;																-- quarter dates only supported by |date= end quarter = mw.ustring.gsub (quarter, ' +', ' ');								-- special case replace multiple space chars with a single space char return cfg.date_names['local'].quarter[quarter] or							-- look for local names first cfg.date_names['en'].quarter[quarter] or							-- failing that, look for English names 0;																	-- not a recognized quarter name end

--[[--< G E T _ P R O P E R _ N A M E _ N U M B E R >--

returns a non-zero number if date contains a recognized proper-name. Capitalization and spelling must be correct.

returns 0 when is not |date=

]]

local function get_proper_name_number (name, param) if 'date' ~= param then return 0;																-- proper-name dates only supported by |date= end return cfg.date_names['local'].named[name] or								-- look for local names dates first cfg.date_names['en'].named[name] or									-- failing that, look for English names 0;																	-- not a recognized named date end

--[[--< G E T _ E L E M E N T _ N U M B E R <--

returns true if month or season or quarter or proper name is valid (properly spelled, capitalized, abbreviated)

]]

local function get_element_number (element, param) local num; local funcs = {get_month_number, get_season_number, get_quarter_number, get_proper_name_number};	-- list of functions to execute in order for _, func in ipairs (funcs) do											-- spin through the function list num = func (element, param);											-- call the function and get the returned number if 0 ~= num then														-- non-zero when valid month season quarter return num;															-- return that number end end return nil;																	-- not valid end

--[[--< I S _ V A L I D _ Y E A R >

Function gets current year from the server and compares it to year from a citation parameter. Years more than one year in the future are not acceptable.

Special case for |pmc-embargo-date=: years more than two years in the future are not acceptable

]]

local function is_valid_year (year, param) if not is_set (year_limit) then year_limit = tonumber(os.date("%Y"))+1;									-- global variable so we only have to fetch it once end

year = tonumber (year) or lang_object:parseFormattedNumber (year);			-- convert to number for the comparison if year and (100 > year) then												-- years less than 100 not supported return false; end if 'pmc-embargo-date' == param then											-- special case for |pmc-embargo-date= return year and (year <= tonumber(os.date("%Y"))+2) or false;			-- years more than two years in the future are not accepted end return year and (year <= year_limit) or false; end

--[[--< I S _ V A L I D _ D A T E >

Returns true if day is less than or equal to the number of days in month and year is no farther into the future than next year; else returns false.

Assumes Julian calendar prior to year 1582 and Gregorian calendar thereafter. Accounts for Julian calendar leap years before 1582 and Gregorian leap years after 1582. Where the two calendars overlap (1582 to approximately 1923) dates are assumed to be Gregorian.

]]

local function is_valid_date (year, month, day, param) local days_in_month = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; local month_length; if not is_valid_year (year, param) then										-- no farther into the future than next year except |pmc-embargo-date= no more than two years in the future return false; end month = tonumber (month);													-- required for YYYY-MM-DD dates if (2 == month) then														-- if February month_length = 28;														-- then 28 days unless if 1582 > tonumber(year) then											-- Julian calendar if 0 == (year%4) then												-- is a leap year? month_length = 29;												-- if leap year then 29 days in February end else																	-- Gregorian calendar if (0 == (year%4) and (0 ~= (year%100) or 0 == (year%400))) then	-- is a leap year? month_length = 29;												-- if leap year then 29 days in February end end else month_length = days_in_month[month]; end

if tonumber (day) > month_length then return false; end return true; end

--[[--< I S _ V A L I D _ M O N T H _ R A N G E _ S T Y L E >--

Months in a range are expected to have the same style: Jan–Mar or October–December but not February–Mar or Jul–August. This function looks in cfg.date_names{} to see if both month names are listed in the long subtable or both are listed in the short subtable. When both have the same style (both are listed in the same table), returns true; false else

]]

local function is_valid_month_range_style (month1, month2) if (cfg.date_names.en.long[month1] and cfg.date_names.en.long[month2]) or					-- are both English names listed in the long subtable? (cfg.date_names.en.short[month1] and cfg.date_names.en.short[month2]) or				-- are both English names listed in the short subtable? (cfg.date_names['local'].long[month1] and cfg.date_names['local'].long[month2]) or		-- are both local names listed in the long subtable? (cfg.date_names['local'].short[month1] and cfg.date_names['local'].short[month2]) then	-- are both local names listed in the short subtable? return true; end return false;																-- names are mixed end

--[[--< I S _ V A L I D _ M O N T H _ S E A S O N _ R A N G E >

Check a pair of months or seasons to see if both are valid members of a month or season pair.

Month pairs are expected to be left to right, earliest to latest in time.

All season ranges are accepted as valid because there are publishers out there who have published a Summer–Spring YYYY issue, hence treat as ok

]]

local function is_valid_month_season_range(range_start, range_end, param) local range_start_number = get_month_number (range_start); local range_end_number;

if 0 == range_start_number then												-- is this a month range? range_start_number = get_season_number (range_start, param);			-- not a month; is it a season? get start season number range_end_number = get_season_number (range_end, param);				-- get end season number

if (0 ~= range_start_number) and (0 ~= range_end_number) and (range_start_number ~= range_end_number) then return true;														-- any season pairing is accepted except when both are the same end return false;															-- range_start and/or range_end is not a season end -- here when range_start is a month range_end_number = get_month_number (range_end);							-- get end month number if range_start_number < range_end_number and								-- range_start is a month; does range_start precede range_end? is_valid_month_range_style (range_start, range_end) then				-- do months have the same style? return true;														-- proper order and same style end return false;																-- range_start month number is greater than or equal to range end number; or range end isn't a month end

--[[--< M A K E _ C O I N S _ D A T E >

This function receives a table of date parts for one or two dates and an empty table reference declared in Module:Citation/CS1. The function is called only for |date= parameters and only if the |date= is determined to be a valid date format. The question of what to do with invalid date formats is not answered here.

The date parts in the input table are converted to an ISO 8601 conforming date string: single whole dates:		yyyy-mm-dd month and year dates:	yyyy-mm year dates:				yyyy ranges:					yyyy-mm-dd/yyyy-mm-dd yyyy-mm/yyyy-mm yyyy/yyyy

Dates in the Julian calendar are reduced to year or year/year so that we don't have to do calendar conversion from Julian to Proleptic Gregorian.

The input table has: year, year2 – always present; if before 1582, ignore months and days if present month, month2 – 0 if not provided, 1-12 for months, 21-24 for seasons; 99 Christmas day, day2 – 0 if not provided, 1-31 for days the output table receives: rftdate:	an ISO 8601 formatted date rftchron:	a free-form version of the date, usually without year which is in rftdate (season ranges and proper-name dates) rftssn:		one of four season keywords: winter, spring, summer, fall (lowercase) rftquarter:	one of four values: 1, 2, 3, 4

]]

local function make_COinS_date (input, tCOinS_date) local date;																	-- one date or first date in a range local date2 = '';															-- end of range date input.year = tonumber (input.year) or lang_object:parseFormattedNumber (input.year);	-- language-aware tonumber input.year2 = tonumber (input.year2) or lang_object:parseFormattedNumber (input.year2);	-- COinS dates are pseudo-ISO 8601 so convert to Arabic numerals

-- start temporary Julian / Gregorian calendar uncertainty detection local year = input.year;													-- this temporary code to determine the extent of sources dated to the Julian/Gregorian local month = tonumber(input.month);										-- interstice 1 October 1582 – 1 January 1926 local day = tonumber (input.day); if (0 ~= day) and															-- day must have a value for this to be a whole date (((1582 == year) and (10 <= month) and (12 >= month)) or				-- any whole 1582 date from 1 October to 31 December or			((1926 == year) and (1 == month) and (1 == input.day)) or			-- 1 January 1926 or				((1582 < year) and (1925 >= year))) then						-- any date 1 January 1583 – 31 December 1925 tCOinS_date.inter_cal_cat = true;							-- set category flag true end -- end temporary Julian / Gregorian calendar uncertainty detection if ((1582 == year) and (10 > month)) or (1582 > year) then					-- if a Julian calendar date tCOinS_date.rftdate = tostring (input.year);							-- &rft.date gets year only return;																	-- done end -- here for all forms of Gregorian dates if 20 < tonumber (input.month) then											-- if season, quarter, or proper-name date date = input.year;														-- &rft.date gets year only if 0 ~= input.year2 and input.year ~= input.year2 then					-- if a range, only the second year portion when not the same as range start year date = string.format ('%.4d/%.4d', input.year, input.year2)			-- assemble the date range end

local season = {[24] = 'winter', [21] = 'spring', [22] = 'summer', [23] = 'fall', [33] = '1', [34] = '2', [35] = '3', [36] = '4', [98] = 'Easter', [99] = 'Christmas'};	-- seasons lowercase, no autumn; proper-names use title case if 0 == input.month2 then												-- single season, quarter, or proper-name date if 40 < tonumber(input.month) then tCOinS_date.rftchron = season[input.month];						-- proper-name date; used in journal metadata only elseif 30 < tonumber(input.month) then tCOinS_date.rftquarter = season[input.month];					-- quarter date; used in journal metadata only else tCOinS_date.rftssn = season[input.month];						-- season date; used in journal metadata only end else																	-- season ranges are lumped into &rft.chron; &rft.ssn and &rft.quarter are left blank if input.year ~= input.year2 then									-- season year – season year range or season year–year if 0 ~= input.month2 then tCOinS_date.rftchron = string.format ('%s %s – %s %s', season[input.month], input.year, season[input.month2], input.year2);	-- used in journal metadata only end else																-- season–season year range tCOinS_date.rftchron = season[input.month] .. '–' .. season[input.month2];	-- season–season year range; used in journal metadata only end end

tCOinS_date.rftdate = tostring (date); return;																	-- done end -- here for gregorian calendar dates if 0 ~= input.day then date = string.format ('%s-%.2d-%.2d', input.year, tonumber(input.month), tonumber(input.day));	-- whole date elseif 0 ~= input.month then date = string.format ('%s-%.2d', input.year, tonumber(input.month));	-- year and month else date = string.format ('%s', input.year);								-- just year end

if 0 ~= input.year2 then if 0 ~= input.day2 then date2 = string.format ('/%s-%.2d-%.2d', input.year2, tonumber(input.month2), tonumber(input.day2));		-- whole date elseif 0 ~= input.month2 then date2 = string.format ('/%s-%.2d', input.year2, tonumber(input.month2));	-- year and month else date2 = string.format ('/%s', input.year2);							-- just year end end tCOinS_date.rftdate = date .. date2;										-- date2 has the '/' separator return; end

--[[--< P A T T E R N S >--

this is the list of patterns for date formats that this module recognizes. Approximately the first half of these patterns represent formats that might be reformatted into another format. Those that might be reformatted have 'indicator' letters that identify the content of the matching capture: 'd' (day), 'm' (month), 'a' (anchor year), 'y' (year); second day, month, year have a '2' suffix.

These patterns are used for both date validation and for reformatting. This table should not be moved to ~/Configuration because changes to this table require changes to check_date and to reformatter and reformat_date

]]

local patterns = { -- year-initial numerical year-month-day ['ymd'] = {'^(%d%d%d%d)%-(%d%d)%-(%d%d)$', 'y', 'm', 'd'}, -- month-initial: month day, year ['Mdy'] = {'^(%D-) +([1-9]%d?), +((%d%d%d%d?)%a?)$', 'm', 'd', 'a', 'y'}, -- month-initial day range: month day–day, year; days are separated by endash ['Md-dy'] = {'^(%D-) +([1-9]%d?)[%-–]([1-9]%d?), +((%d%d%d%d)%a?)$', 'm', 'd', 'd2', 'a', 'y'}, -- day-initial: day month year ['dMy'] = {'^([1-9]%d?) +(%D-) +((%d%d%d%d?)%a?)$', 'd', 'm', 'a', 'y'}, -- year-initial: year month day; day: 1 or 2 two digits, leading zero allowed; not supported at en.wiki --	['yMd'] = {'^((%d%d%d%d?)%a?) +(%D-) +(%d%d?)$', 'a', 'y', 'm', 'd'}, -- day-range-initial: day–day month year; days are separated by endash ['d-dMy'] = {'^([1-9]%d?)[%-–]([1-9]%d?) +(%D-) +((%d%d%d%d)%a?)$', 'd', 'd2', 'm', 'a', 'y'}, -- day initial month-day-range: day month - day month year; uses spaced endash ['dM-dMy'] = {'^([1-9]%d?) +(%D-) +[%-–] +([1-9]%d?) +(%D-) +((%d%d%d%d)%a?)$', 'd', 'm', 'd2', 'm2', 'a', 'y'}, -- month initial month-day-range: month day – month day, year; uses spaced endash ['Md-Mdy'] = {'^(%D-) +([1-9]%d?) +[%-–] +(%D-) +([1-9]%d?), +((%d%d%d%d)%a?)$','m', 'd', 'm2', 'd2', 'a', 'y'}, -- day initial month-day-year-range: day month year - day month year; uses spaced endash ['dMy-dMy'] = {'^([1-9]%d?) +(%D-) +(%d%d%d%d) +[%-–] +([1-9]%d?) +(%D-) +((%d%d%d%d)%a?)$', 'd', 'm', 'y', 'd2', 'm2', 'a', 'y2'}, -- month initial month-day-year-range: month day, year – month day, year; uses spaced endash ['Mdy-Mdy'] = {'^(%D-) +([1-9]%d?), +(%d%d%d%d) +[%-–] +(%D-) +([1-9]%d?), +((%d%d%d%d)%a?)$', 'm', 'd', 'y', 'm2', 'd2', 'a', 'y2'},

-- these date formats cannot be converted, per se, but month name can be rendered short or long -- month/season year - month/season year; separated by spaced endash ['My-My'] = {'^(%D-) +(%d%d%d%d) +[%-–] +(%D-) +((%d%d%d%d)%a?)$', 'm', 'y', 'm2', 'a', 'y2'}, -- month/season range year; months separated by endash ['M-My'] = {'^(%D-)[%-–](%D-) +((%d%d%d%d)%a?)$', 'm', 'm2', 'a', 'y'}, -- month/season year or proper-name year; quarter year when First Quarter YYYY etc.	['My'] = {'^([^%d–]-) +((%d%d%d%d)%a?)$', 'm', 'a', 'y'},					-- this way because endash is a member of %D; %D- will match January–March 2019 when it shouldn't

-- these date formats cannot be converted ['Sy4-y2'] = {'^(%D-) +((%d%d)%d%d)[%-–]((%d%d)%a?)$'},						-- special case Winter/Summer year-year (YYYY-YY); year separated with unspaced endash ['Sy-y'] = {'^(%D-) +(%d%d%d%d)[%-–]((%d%d%d%d)%a?)$'},						-- special case Winter/Summer year-year; year separated with unspaced endash ['y-y'] = {'^(%d%d%d%d?)[%-–]((%d%d%d%d?)%a?)$'},							-- year range: YYY-YYY or YYY-YYYY or YYYY–YYYY; separated by unspaced endash; 100-9999 ['y4-y2'] = {'^((%d%d)%d%d)[%-–]((%d%d)%a?)$'},								-- year range: YYYY–YY; separated by unspaced endash ['y'] = {'^((%d%d%d%d?)%a?)$'},												-- year; here accept either YYY or YYYY }

--[[--< I S _ V A L I D _ E M B A R G O _ D A T E >

returns true and date value if that value has proper dmy, mdy, ymd format.

returns false and 9999 (embargoed forever) when date value is not proper format; assumes that when |pmc-embargo-date= is set, the editor intended to embargo a PMC but |pmc-embargo-date= does not hold a single date.

]]

local function is_valid_embargo_date (v) if v:match (patterns['ymd'][1]) or											-- ymd v:match (patterns['Mdy'][1]) or											-- dmy v:match (patterns['dMy'][1]) then										-- mdy return true, v;	end return false, '9999';														-- if here not good date so return false and set embargo date to long time in future end

--[[--< C H E C K _ D A T E >--

Check date format to see that it is one of the formats approved by WP:DATESNO or WP:DATERANGE. Exception: only allowed range separator is endash. Additionally, check the date to see that it is a real date: no 31 in 30-day months; no 29 February when not a leap year. Months, both long-form and three character abbreviations, and seasons must be spelled correctly. Future years beyond next year are not allowed.

If the date fails the format tests, this function returns false and does not return values for anchor_year and COinS_date. When this happens, the date parameter is (DEBUG: not?) used in the COinS metadata and the CITEREF identifier gets its year from the year parameter if present otherwise CITEREF does not get a date value.

Inputs: date_string - date string from date-holding parameters (date, year, publication-date, access-date, pmc-embargo-date, archive-date, lay-date)

Returns: false if date string is not a real date; else true, anchor_year, COinS_date anchor_year can be used in CITEREF anchors COinS_date is ISO 8601 format date; see make_COInS_date

]]

local function check_date (date_string, param, tCOinS_date) local year;																	-- assume that year2, months, and days are not used; local year2 = 0;															-- second year in a year range local month = 0; local month2 = 0;															-- second month in a month range local day = 0; local day2 = 0;																-- second day in a day range local anchor_year; local coins_date;

if date_string:match (patterns['ymd'][1]) then								-- year-initial numerical year month day format year, month, day = date_string:match (patterns['ymd'][1]); if 12 < tonumber(month) or 1 > tonumber(month) or 1582 > tonumber(year) or 0 == tonumber(day) then return false; end	-- month or day number not valid or not Gregorian calendar anchor_year = year; elseif mw.ustring.match(date_string, patterns['Mdy'][1]) then				-- month-initial: month day, year month, day, anchor_year, year = mw.ustring.match(date_string, patterns['Mdy'][1]); month = get_month_number (month); if 0 == month then return false; end									-- return false if month text isn't one of the twelve months elseif mw.ustring.match(date_string, patterns['Md-dy'][1]) then				-- month-initial day range: month day–day, year; days are separated by endash month, day, day2, anchor_year, year = mw.ustring.match(date_string, patterns['Md-dy'][1]); if tonumber(day) >= tonumber(day2) then return false; end				-- date range order is left to right: earlier to later; dates may not be the same; month = get_month_number (month); if 0 == month then return false; end									-- return false if month text isn't one of the twelve months month2=month;															-- for metadata year2 = year;

elseif mw.ustring.match(date_string, patterns['dMy'][1]) then				-- day-initial: day month year day, month, anchor_year, year = mw.ustring.match(date_string, patterns['dMy'][1]); month = get_month_number (month); if 0 == month then return false; end									-- return false if month text isn't one of the twelve months

-- NOT supported at en.wiki	elseif mw.ustring.match(date_string, patterns['yMd'][1]) then				-- year-initial: year month day; day: 1 or 2 two digits, leading zero allowed		anchor_year, year, month, day = mw.ustring.match(date_string, patterns['yMd'][1]);		month = get_month_number (month);		if 0 == month then return false; end									-- return false if month text isn't one of the twelve months -- end NOT supported at en.wiki

elseif mw.ustring.match(date_string, patterns['d-dMy'][1]) then				-- day-range-initial: day–day month year; days are separated by endash day, day2, month, anchor_year, year = mw.ustring.match(date_string, patterns['d-dMy'][1]); if tonumber(day) >= tonumber(day2) then return false; end				-- date range order is left to right: earlier to later; dates may not be the same; month = get_month_number (month); if 0 == month then return false; end									-- return false if month text isn't one of the twelve months month2 = month;															-- for metadata year2 = year;

elseif mw.ustring.match(date_string, patterns['dM-dMy'][1]) then			-- day initial month-day-range: day month - day month year; uses spaced endash day, month, day2, month2, anchor_year, year = mw.ustring.match(date_string, patterns['dM-dMy'][1]); if (not is_valid_month_season_range(month, month2)) or not is_valid_year(year) then return false; end	-- date range order is left to right: earlier to later; month = get_month_number (month);										-- for metadata month2 = get_month_number (month2); year2 = year;

elseif mw.ustring.match(date_string, patterns['Md-Mdy'][1]) then			-- month initial month-day-range: month day – month day, year; uses spaced endash month, day, month2, day2, anchor_year, year = mw.ustring.match(date_string, patterns['Md-Mdy'][1]); if (not is_valid_month_season_range(month, month2, param)) or not is_valid_year(year) then return false; end month = get_month_number (month);										-- for metadata month2 = get_month_number (month2); year2 = year;

elseif mw.ustring.match(date_string, patterns['dMy-dMy'][1]) then			-- day initial month-day-year-range: day month year - day month year; uses spaced endash day, month, year, day2, month2, anchor_year, year2 = mw.ustring.match(date_string, patterns['dMy-dMy'][1]); if tonumber(year2) <= tonumber(year) then return false; end				-- must be sequential years, left to right, earlier to later if not is_valid_year(year2) or not is_valid_month_range_style(month, month2) then return false; end		-- year2 no more than one year in the future; months same style month = get_month_number (month);										-- for metadata month2 = get_month_number (month2); if 0 == month or 0 == month2 then return false; end						-- both must be valid

elseif mw.ustring.match(date_string, patterns['Mdy-Mdy'][1]) then			-- month initial month-day-year-range: month day, year – month day, year; uses spaced endash month, day, year, month2, day2, anchor_year, year2 = mw.ustring.match(date_string, patterns['Mdy-Mdy'][1]); if tonumber(year2) <= tonumber(year) then return false; end				-- must be sequential years, left to right, earlier to later if not is_valid_year(year2) or not is_valid_month_range_style(month, month2) then return false; end		-- year2 no more than one year in the future; months same style month = get_month_number (month);										-- for metadata month2 = get_month_number(month2); if 0 == month or 0 == month2 then return false; end						-- both must be valid

elseif mw.ustring.match(date_string, patterns['Sy4-y2'][1]) then			-- special case Winter/Summer year-year (YYYY-YY); year separated with unspaced endash local century; month, year, century, anchor_year, year2 = mw.ustring.match(date_string, patterns['Sy4-y2'][1]); if 'Winter' ~= month and 'Summer' ~= month then return false end;		-- 'month' can only be Winter or Summer anchor_year = year .. '–' .. anchor_year;								-- assemble anchor_year from both years year2 = century..year2;													-- add the century to year2 for comparisons if 1 ~= tonumber(year2) - tonumber(year) then return false; end			-- must be sequential years, left to right, earlier to later if not is_valid_year(year2) then return false; end						-- no year farther in the future than next year month = get_season_number(month, param);

elseif mw.ustring.match(date_string, patterns['Sy-y'][1]) then				-- special case Winter/Summer year-year; year separated with unspaced endash month, year, anchor_year, year2 = mw.ustring.match(date_string, patterns['Sy-y'][1]); month = get_season_number (month, param);								-- can only be winter or summer; also for metadata if (month ~= cfg.date_names['en'].season['Winter']) and (month ~= cfg.date_names['en'].season['Summer']) then return false;														-- not Summer or Winter; abandon end anchor_year = year .. '–' .. anchor_year;								-- assemble anchor_year from both years if 1 ~= tonumber(year2) - tonumber(year) then return false; end			-- must be sequential years, left to right, earlier to later if not is_valid_year(year2) then return false; end						-- no year farther in the future than next year

elseif mw.ustring.match(date_string, patterns['My-My'][1]) then				-- month/season year - month/season year; separated by spaced endash month, year, month2, anchor_year, year2 = mw.ustring.match(date_string, patterns['My-My'][1]); anchor_year = year .. '–' .. anchor_year;								-- assemble anchor_year from both years if tonumber(year) >= tonumber(year2) then return false; end				-- left to right, earlier to later, not the same if not is_valid_year(year2) then return false; end						-- no year farther in the future than next year if 0 ~= get_month_number(month) and 0 ~= get_month_number(month2) and is_valid_month_range_style(month, month2) then 	-- both must be month year, same month style month = get_month_number(month); month2 = get_month_number(month2); elseif 0 ~= get_season_number(month, param) and 0 ~= get_season_number(month2, param) then	-- both must be season year, not mixed month = get_season_number(month, param); month2 = get_season_number(month2, param); else return false; end

elseif mw.ustring.match(date_string, patterns['M-My'][1]) then				-- month/season range year; months separated by endash month, month2, anchor_year, year = mw.ustring.match(date_string, patterns['M-My'][1]); if (not is_valid_month_season_range(month, month2, param)) or (not is_valid_year(year)) then return false; end if 0 ~= get_month_number(month) then									-- determined to be a valid range so just check this one to know if month or season month = get_month_number(month); month2 = get_month_number(month2); if 0 == month or 0 == month2 then return false; end else month = get_season_number(month, param); month2 = get_season_number(month2, param); end year2 = year; elseif mw.ustring.match(date_string, patterns['My'][1]) then				-- month/season/quarter/proper-name year month, anchor_year, year = mw.ustring.match(date_string, patterns['My'][1]); if not is_valid_year(year) then return false; end month = get_element_number(month, param);								-- get month season quarter proper-name number or nil if not month then return false; end										-- not valid whatever it is

elseif mw.ustring.match(date_string, patterns['y-y'][1]) then				-- Year range: YYY-YYY or YYY-YYYY or YYYY–YYYY; separated by unspaced endash; 100-9999 year, anchor_year, year2 = mw.ustring.match(date_string, patterns['y-y'][1]); anchor_year = year .. '–' .. anchor_year;								-- assemble anchor year from both years if tonumber(year) >= tonumber(year2) then return false; end				-- left to right, earlier to later, not the same if not is_valid_year(year2) then return false; end						-- no year farther in the future than next year

elseif mw.ustring.match(date_string, patterns['y4-y2'][1]) then				-- Year range: YYYY–YY; separated by unspaced endash local century; year, century, anchor_year, year2 = mw.ustring.match(date_string, patterns['y4-y2'][1]); anchor_year = year .. '–' .. anchor_year;								-- assemble anchor year from both years

if 13 > tonumber(year2) then return false; end							-- don't allow 2003-05 which might be May 2003 year2 = century .. year2;												-- add the century to year2 for comparisons if tonumber(year) >= tonumber(year2) then return false; end				-- left to right, earlier to later, not the same if not is_valid_year(year2) then return false; end						-- no year farther in the future than next year

if in_array (param, {'date', 'publication-date', 'year'}) then			-- here when 'valid' abbreviated year range; if one of these parameters add_prop_cat ('year-range-abbreviated');							-- add properties cat end

elseif mw.ustring.match(date_string, patterns['y'][1]) then					-- year; here accept either YYY or YYYY anchor_year, year = mw.ustring.match(date_string, patterns['y'][1]); if false == is_valid_year(year) then return false; end

else return false;															-- date format not one of the MOS:DATE approved formats end

if param ~= 'date' then														-- CITEREF disambiguation only allowed in |date=; |year= & |publication-date= promote to date if anchor_year:match ('%l$') then return false; end end

if 'access-date' == param then												-- test access-date here because we have numerical date parts if 0 ~= year and 0 ~= month and 0 ~= day and 							-- all parts of a single date required 0 == year2 and 0 == month2 and 0 == day2 then						-- none of these; access-date must not be a range if not is_valid_accessdate(year .. '-' .. month .. '-' .. day) then return false;												-- return false when access-date out of bounds end else return false;														-- return false when access-date is a range of two dates end end

if 'archive-date' == param then												-- test archive-date here because we have numerical date parts if not (0 ~= year and 0 ~= month and 0 ~= day and						-- all parts of a single date required			0 == year2 and 0 == month2 and 0 == day2) then						-- none of these; archive-date must not be a range return false;													-- return false when archive-date is a range of two dates end end

local result=true;															-- check whole dates for validity; assume true because not all dates will go through this test if 0 ~= year and 0 ~= month and 0 ~= day and 0 == year2 and 0 == month2 and 0 == day2 then		-- YMD (simple whole date) result = is_valid_date (year, month, day, param);						-- for |pmc-embargo-date=

elseif 0 ~= year and 0 ~= month and 0 ~= day and 0 == year2 and 0 == month2 and 0 ~= day2 then	-- YMD-d (day range) result = is_valid_date (year, month, day); result = result and is_valid_date (year, month, day2);

elseif 0 ~= year and 0 ~= month and 0 ~= day and 0 == year2 and 0 ~= month2 and 0 ~= day2 then	-- YMD-md (day month range) result = is_valid_date (year, month, day); result = result and is_valid_date (year, month2, day2);

elseif 0 ~= year and 0 ~= month and 0 ~= day and 0 ~= year2 and 0 ~= month2 and 0 ~= day2 then	-- YMD-ymd (day month year range) result = is_valid_date(year, month, day); result = result and is_valid_date(year2, month2, day2); end if false == result then return false; end

if nil ~= tCOinS_date then													-- this table only passed into this function when testing |date= parameter values make_COinS_date ({year = year, month = month, day = day, year2 = year2, month2 = month2, day2 = day2}, tCOinS_date);	-- make an ISO 8601 date string for COinS end return true, anchor_year;													-- format is good and date string represents a real date end

--[[--< D A T E S >

Cycle the date-holding parameters in passed table date_parameters_list through check_date to check compliance with MOS:DATE. For all valid dates, check_date returns true. The |date= parameter test is unique, it is the only date holding parameter from which values for anchor_year (used in CITEREF identifiers) and COinS_date (used in the COinS metadata) are derived. The |date= parameter is the only date-holding parameter that is allowed to contain the no-date keywords "n.d." or "nd" (without quotes).

Unlike most error messages created in this module, only one error message is created by this function. Because all of the date holding parameters are processed serially, parameters with errors are added to the  sequence table as the dates are tested.

]]

local function dates(date_parameters_list, tCOinS_date, error_list) local anchor_year;															-- will return as nil if the date being tested is not |date= local COinS_date;															-- will return as nil if the date being tested is not |date= local embargo_date;															-- if embargo date is a good dmy, mdy, ymd date then holds original value else reset to 9999 local good_date = false;

for k, v in pairs(date_parameters_list) do									-- for each date-holding parameter in the list if is_set(v.val) then													-- if the parameter has a value v.val = mw.ustring.gsub(v.val, '%d', cfg.date_names.local_digits);	-- translate 'local' digits to Western 0-9 if v.val:match("^c%. [1-9]%d%d%d?%a?$") then						-- special case for c. year or with or without CITEREF disambiguator - only |date= and |year= local year = v.val:match("c%. ([1-9]%d%d%d?)%a?");				-- get the year portion so it can be tested if 'date' == k then anchor_year, COinS_date = v.val:match("((c%. [1-9]%d%d%d?)%a?)");	-- anchor year and COinS_date only from |date= parameter good_date = is_valid_year(year); elseif 'year' == k then good_date = is_valid_year(year); end elseif 'date' == k then												-- if the parameter is |date= if v.val:match("^n%.d%.%a?$") then -- ToDo: I18N								-- if |date=n.d. with or without a CITEREF disambiguator good_date, anchor_year, COinS_date = true, v.val:match("((n%.d%.)%a?)"); -- ToDo: I18N	-- "n.d."; no error when date parameter is set to no date elseif v.val:match("^nd%a?$") then -- ToDo: I18N								-- if |date=nd with or without a CITEREF disambiguator good_date, anchor_year, COinS_date = true, v.val:match("((nd)%a?)"); -- ToDo: I18N	-- "nd";	no error when date parameter is set to no date else good_date, anchor_year, COinS_date = check_date (v.val, k, tCOinS_date);	-- go test the date end elseif 'year' == k then												-- if the parameter is |year= it should hold only a year value if v.val:match("^[1-9]%d%d%d?%a?$") then						-- if |year = 3 or 4 digits only with or without a CITEREF disambiguator good_date, anchor_year, COinS_date = true, v.val:match("((%d+)%a?)"); end elseif 'pmc-embargo-date' == k then									-- if the parameter is |pmc-embargo-date= good_date = check_date (v.val, k);								-- go test the date if true == good_date then										-- if the date is a valid date good_date, embargo_date = is_valid_embargo_date (v.val);	-- is |pmc-embargo-date= date a single dmy, mdy, or ymd formatted date? yes: returns embargo date; no: returns 9999 end else																-- any other date-holding parameter good_date = check_date (v.val, k);								-- go test the date end if false == good_date then											-- assemble one error message so we don't add the tracking category multiple times table.insert (error_list, wrap_style ('parameter', v.name));	-- make parameter name suitable for error message list end end end return anchor_year, embargo_date;											-- and done end

--[[--< Y E A R _ D A T E _ C H E C K >

Compare the value provided in |year= with the year value(s) provided in |date=. This function sets a local numeric value: 0 - year value does not match the year value in date 1 - (default) year value matches the year value in date or one of the year values when date contains two years 2 - year value matches the year value in date when date is in the form YYYY-MM-DD and year is disambiguated (|year=YYYYx)

the numeric value in determines the 'output' if any from this function: 0 – adds error message to error_list sequence table 1 – adds maint cat 2 – does nothing

]]

local function year_date_check (year_string, year_origin, date_string, date_origin, error_list) local year; local date1; local date2; local result = 1;															-- result of the test; assume that the test passes

year = year_string:match ('(%d%d%d%d?)');

if date_string:match ('%d%d%d%d%-%d%d%-%d%d') and year_string:match ('%d%d%d%d%a') then	--special case where both date and year are required YYYY-MM-DD and YYYYx date1 = date_string:match ('(%d%d%d%d)'); year = year_string:match ('(%d%d%d%d)'); if year ~= date1 then result = 0;															-- years don't match else result = 2;															-- years match; but because disambiguated, don't add to maint cat end elseif date_string:match ("%d%d%d%d?.-%d%d%d%d?") then						-- any of the standard range formats of date with two three- or four-digit years date1, date2 = date_string:match ("(%d%d%d%d?).-(%d%d%d%d?)"); if year ~= date1 and year ~= date2 then result = 0; end

elseif mw.ustring.match(date_string, "%d%d%d%d[%-–]%d%d") then				-- YYYY-YY date ranges local century; date1, century, date2 = mw.ustring.match(date_string, "((%d%d)%d%d)[%-–]+(%d%d)"); date2 = century..date2;													-- convert YY to YYYY if year ~= date1 and year ~= date2 then result = 0; end

elseif date_string:match ("%d%d%d%d?") then									-- any of the standard formats of date with one year date1 = date_string:match ("(%d%d%d%d?)"); if year ~= date1 then result = 0; end else																		-- should never get here; this function called only when no other date errors result = 0;																-- no recognizable year in date end

if 0 == result then															-- year / date mismatch table.insert (error_list, substitute (cfg.messages['mismatch'], {year_origin, date_origin}));	-- add error message to error_list sequence table elseif 1 == result then														-- redundant year / date set_message ('maint_date_year');										-- add a maint cat end end

--[[--< R E F O R M A T T E R >

reformat 'date' into new format specified by format_param if pattern_idx (the current format of 'date') can be reformatted. Does the grunt work for reformat_dates.

The table re_formats maps pattern_idx (current format) and format_param (desired format) to a table that holds: format string used by string.format identifier letters ('d', 'm', 'y', 'd2', 'm2', 'y2') that serve as indexes into a table t{} that holds captures from mw.ustring.match for the various date parts specified by patterns[pattern_idx][1]

Items in patterns{} have the general form: ['ymd'] = {'^(%d%d%d%d)%-(%d%d)%-(%d%d)$', 'y', 'm', 'd'}, where: ['ymd'] is pattern_idx patterns['ymd'][1] is the match pattern with captures for mw.ustring.match patterns['ymd'][2] is an indicator letter identifying the content of the first capture patterns['ymd'][3] ... the second capture etc.

when a pattern matches a date, the captures are loaded into table t{} in capture order using the idemtifier characters as indexes into t{} For the above, a ymd date is in t{} as: t.y = first capture (year), t.m = second capture (month), t.d = third capture (day)

To reformat, this function is called with the pattern_idx that matches the current format of the date and with format_param set to the desired format. This function loads table t{} as described and then calls string.format with the format string specified by re_format[pattern_idx][format_param][1] using values taken from t{} according to the capture identifier letters specified by patterns[pattern_idx][format_param][n] where n is 2..

]]

local re_formats = { ['ymd'] = {																	-- date format is ymd; reformat to: ['mdy'] = {'%s %s, %s', 'm', 'd', 'y'},									-- |df=mdy ['dmy'] = {'%s %s %s', 'd', 'm', 'y'},									-- |df=dmy --		['yMd'] = {'%s %s %s', 'y', 'm', 'd'},								-- |df=yMd; not supported at en.wiki },	['Mdy'] = {																	-- date format is Mdy; reformat to: ['mdy'] = {'%s %s, %s', 'm', 'd', 'y'},									-- for long/short reformatting ['dmy'] = {'%s %s %s', 'd', 'm', 'y'},									-- |df=dmy ['ymd'] = {'%s-%s-%s', 'y', 'm', 'd'},									-- |df=ymd --		['yMd'] = {'%s %s %s', 'y', 'm', 'd'},								-- |df=yMd; not supported at en.wiki },	['dMy'] = {																	-- date format is dMy; reformat to: ['dmy'] = {'%s %s %s', 'd', 'm', 'y'},									-- for long/short reformatting ['mdy'] = {'%s %s, %s', 'm', 'd', 'y'},									-- |df=mdy ['ymd'] = {'%s-%s-%s', 'y', 'm', 'd'},									-- |df=ymd --		['yMd'] = {'%s %s %s', 'y', 'm', 'd'},								-- |df=yMd; not supported at en.wiki },	['Md-dy'] = {																-- date format is Md-dy; reformat to: ['mdy'] = {'%s %s–%s, %s', 'm', 'd', 'd2', 'y'},						-- for long/short reformatting ['dmy'] = {'%s–%s %s %s', 'd', 'd2', 'm', 'y'},							-- |df=dmy -> d-dMy },	['d-dMy'] = {																-- date format is d-d>y; reformat to: ['dmy'] = {'%s–%s %s %s', 'd', 'd2', 'm', 'y'},							-- for long/short reformatting ['mdy'] = {'%s %s–%s, %s', 'm', 'd', 'd2', 'y'},						-- |df=mdy -> Md-dy },	['dM-dMy'] = {																-- date format is dM-dMy; reformat to: ['dmy'] = {'%s %s – %s %s %s', 'd', 'm', 'd2', 'm2', 'y'},				-- for long/short reformatting ['mdy'] = {'%s %s – %s %s, %s', 'm', 'd', 'm2', 'd2', 'y'},				-- |df=mdy -> Md-Mdy },	['Md-Mdy'] = {																-- date format is Md-Mdy; reformat to: ['mdy'] = {'%s %s – %s %s, %s', 'm', 'd', 'm2', 'd2', 'y'},			-- for long/short reformatting ['dmy'] = {'%s %s – %s %s %s', 'd', 'm', 'd2', 'm2', 'y'},				-- |df=dmy -> dM-dMy },	['dMy-dMy'] = {																-- date format is dMy-dMy; reformat to: ['dmy'] = {'%s %s %s – %s %s %s', 'd', 'm', 'y', 'd2', 'm2', 'y2'},		-- for long/short reformatting ['mdy'] = {'%s %s, %s – %s %s, %s', 'm', 'd', 'y', 'm2', 'd2', 'y2'},	-- |df=mdy -> Mdy-Mdy },	['Mdy-Mdy'] = {																-- date format is Mdy-Mdy; reformat to: ['mdy'] = {'%s %s, %s – %s %s, %s', 'm', 'd', 'y', 'm2', 'd2', 'y2'},	-- for long/short reformatting ['dmy'] = {'%s %s %s – %s %s %s', 'd', 'm', 'y', 'd2', 'm2', 'y2'},		-- |df=dmy -> dMy-dMy },	['My-My'] = {																-- these for long/short reformatting ['any'] = {'%s %s – %s %s', 'm', 'y', 'm2', 'y2'},						-- dmy/mdy agnostic },	['M-My'] = {																-- these for long/short reformatting ['any'] = {'%s–%s %s', 'm', 'm2', 'y'},									-- dmy/mdy agnostic },	['My'] = {																	-- these for long/short reformatting ['any'] = {'%s %s', 'm', 'y'},											-- dmy/mdy agnostic },	--	['yMd'] = {																-- not supported at en.wiki --		['mdy'] = {'%s %s, %s', 'm', 'd', 'y'},								-- |df=mdy --		['dmy'] = {'%s %s %s', 'd', 'm', 'y'},								-- |df=dmy --		['ymd'] = {'%s-%s-%s', 'y', 'm', 'd'},								-- |df=ymd --		},	}

local function reformatter (date, pattern_idx, format_param, mon_len) if not in_array (pattern_idx, {'ymd', 'Mdy', 'Md-dy', 'dMy', 'yMd', 'd-dMy', 'dM-dMy', 'Md-Mdy', 'dMy-dMy', 'Mdy-Mdy', 'My-My', 'M-My', 'My'}) then return;																	-- not in this set of date format patterns then not a reformattable date end if 'ymd' == format_param and in_array (pattern_idx, {'ymd', 'Md-dy', 'd-dMy', 'dM-dMy', 'Md-Mdy', 'dMy-dMy', 'Mdy-Mdy', 'My-My', 'M-My', 'My'}) then return;																	-- ymd date ranges not supported at en.wiki; no point in reformatting ymd to ymd end

if in_array (pattern_idx, {'My', 'M-My', 'My-My'}) then						-- these are not dmy/mdy so can't be 'reformatted' into either format_param = 'any';													-- so format-agnostic end

-- yMd is not supported at en.wiki; when yMd is supported at your wiki, uncomment the next line --	if 'yMd' == format_param and in_array (pattern_idx, {'yMd', 'Md-dy', 'd-dMy', 'dM-dMy', 'Md-Mdy', 'dMy-dMy', 'Mdy-Mdy'}) then	-- these formats not convertable; yMd not supported at en.wiki if 'yMd' == format_param then												-- yMd not supported at en.wiki; when yMd is supported at your wiki, remove or comment-out this line return;																	-- not a reformattable date end local c1, c2, c3, c4, c5, c6, c7;											-- these hold the captures specified in patterns[pattern_idx][1] c1, c2, c3, c4, c5, c6, c7 = mw.ustring.match (date, patterns[pattern_idx][1]);	-- get the captures

local t = {																	-- table that holds k/v pairs of date parts from the captures and patterns[pattern_idx][2..] [patterns[pattern_idx][2]] = c1;										-- at minimum there is always one capture with a matching indicator letter [patterns[pattern_idx][3] or 'x'] = c2;									-- patterns can have a variable number of captures; each capture requires an indicator letter; [patterns[pattern_idx][4] or 'x'] = c3;									-- where there is no capture, there is no indicator letter so n in patterns[pattern_idx][n] will be nil; [patterns[pattern_idx][5] or 'x'] = c4;									-- the 'x' here spoofs an indicator letter to prevent 'table index is nil' error [patterns[pattern_idx][6] or 'x'] = c5; [patterns[pattern_idx][7] or 'x'] = c6; [patterns[pattern_idx][8] or 'x'] = c7; };

if t.a then																	-- if this date has an anchor year capture (all convertable date formats except ymd) if t.y2 then															-- for year range date formats t.y2 = t.a;															-- use the anchor year capture when reassembling the date else																	-- here for single date formats (except ymd) t.y = t.a;															-- use the anchor year capture when reassembling the date end end

if tonumber(t.m) then														-- if raw month is a number (converting from ymd) if 's' == mon_len then													-- if we are to use abbreviated month names t.m = cfg.date_names['inv_local_short'][tonumber(t.m)];					-- convert it to a month name else t.m = cfg.date_names['inv_local_long'][tonumber(t.m)];					-- convert it to a month name end t.d = t.d:gsub ('0(%d)', '%1');											-- strip leading '0' from day if present elseif 'ymd' == format_param then											-- when converting to ymd t.y = t.y:gsub ('%a', '');												-- strip CITREF disambiguator if present; anchor year already known so process can proceed; TODO: maint message? if 1582 > tonumber (t.y) then											-- ymd format dates not allowed before 1582 return; end t.m = string.format ('%02d', get_month_number (t.m));					-- make sure that month and day are two digits t.d = string.format ('%02d', t.d); elseif mon_len then															-- if mon_len is set to either 'short' or 'long' for _, mon in ipairs ({'m', 'm2'}) do									-- because there can be two month names, check both if t[mon] then t[mon] = get_month_number (t[mon]);								-- get the month number for this month (is length agnostic) if 0 == t[mon] then return; end									-- seasons and named dates can't be converted t[mon] = (('s' == mon_len) and cfg.date_names['inv_local_short'][t[mon]]) or cfg.date_names['inv_local_long'][t[mon]];	-- fetch month name according to length end end end

local new_date = string.format (re_formats[pattern_idx][format_param][1],	-- format string		t[re_formats[pattern_idx][format_param][2]],							-- named captures from t{}		t[re_formats[pattern_idx][format_param][3]],		t[re_formats[pattern_idx][format_param][4]],		t[re_formats[pattern_idx][format_param][5]],		t[re_formats[pattern_idx][format_param][6]],		t[re_formats[pattern_idx][format_param][7]],		t[re_formats[pattern_idx][format_param][8]]		);

return new_date; end

--[[-< R E F O R M A T _ D A T E S >--

Reformats existing dates into the format specified by format.

format is one of several manual keywords: dmy, dmy-all, mdy, mdy-all, ymd, ymd-all. The -all version includes access- and archive-dates; otherwise these dates are not reformatted.

This function allows automatic date formatting. In ~/Configuration, the article source is searched for one of the templates. If found, xxx becomes the global date format as xxx-all. If |cs1-dates= in has legitimate value then that value determines how cs1|2 dates will be rendered. Legitimate values for |cs1-dates= are: l - all dates are rendered with long month names ls - publication dates use long month names; access-/archive-dates use abbreviated month names ly - publication dates use long month names; access-/archive-dates rendered in ymd format s - all dates are rendered with abbreviated (short) month names sy - publication dates use abbreviated month names; access-/archive-dates rendered in ymd format y - all dates are rendered in ymd format

the format argument for automatic date formatting will be the format specified by with the value supplied by |cs1-dates so one of: xxx-l, xxx-ls, xxx-ly, xxx-s, xxx-sy, xxx-y, or simply xxx (|cs1-dates= empty, omitted, or invalid) where xxx shall be either of dmy or mdy.

dates are extracted from date_parameters_list, reformatted (if appropriate), and then written back into the list in the new format. Dates in date_parameters_list are presumed here to be valid (no errors). This function returns true when a date has been reformatted, false else. Actual reformatting is done by reformatter.

]]

local function reformat_dates (date_parameters_list, format) local all = false;															-- set to false to skip access- and archive-dates local len_p = 'l';															-- default publication date length shall be long local len_a = 'l';															-- default access-/archive-date length shall be long local result = false; local new_date; if format:match('%a+%-all') then											-- manual df keyword; auto df keyword when length not specified in ; format = format:match('(%a+)%-all');									-- extract the format all = true;																-- all dates are long format dates because this keyword doesn't specify length elseif format:match('%a+%-[lsy][sy]?') then									-- auto df keywords; internal only all = true;																-- auto df applies to all dates; use length specified by capture len_p for all dates format, len_p, len_a = format:match('(%a+)%-([lsy])([sy]?)');			-- extract the format and length keywords if 'y' == len_p then													-- because allowed by MOS:DATEUNIFY (sort of) range dates and My dates not reformatted format = 'ymd';														-- override elseif (not is_set(len_a)) or (len_p == len_a) then						-- no access-/archive-date length specified or same length as publication dates then len_a = len_p;														-- in case len_a not set end end																			-- else only publication dates and they are long

for param_name, param_val in pairs (date_parameters_list) do				-- for each date-holding parameter in the list if is_set (param_val.val) then											-- if the parameter has a value if not (not all and in_array (param_name, {'access-date', 'archive-date'})) then	-- skip access- or archive-date unless format is xxx-all; yeah, ugly; TODO: find a better way for pattern_idx, pattern in pairs (patterns) do					if mw.ustring.match (param_val.val, pattern[1]) then if all and in_array (param_name, {'access-date', 'archive-date'}) then	-- if this date is an access- or archive-date new_date = reformatter (param_val.val, pattern_idx, (('y' == len_a) and 'ymd') or format, len_a);	-- choose ymd or dmy/mdy according to len_a setting else													-- all other dates new_date = reformatter (param_val.val, pattern_idx, format, len_p); end if new_date then										-- set when date was reformatted date_parameters_list[param_name].val = new_date;	-- update date in date list result = true;										-- and announce that changes have been made break; end end	-- if				end		-- for end			-- if		end				-- if	end					-- for return result;																-- declare boolean result and done end

--[[--< D A T E _ H Y P H E N _ T O _ D A S H >

Loops through the list of date-holding parameters and converts any hyphen to an ndash. Not called if the cs1|2 template has any date errors.

Modifies the date_parameters_list and returns true if hyphens are replaced, else returns false.

]]

local function date_hyphen_to_dash (date_parameters_list) local result = false; local n;	for param_name, param_val in pairs(date_parameters_list) do					-- for each date-holding parameter in the list if is_set (param_val.val) and not mw.ustring.match (param_val.val, patterns.ymd[1]) then			-- for those that are not ymd dates (ustring because here digits may not be Western) param_val.val, n = param_val.val:gsub ('%-', '–');				-- replace any hyphen with ndash if 0 ~= n then date_parameters_list[param_name].val = param_val.val;		-- update the list result = true; end end end return result;																-- so we know if any hyphens were replaced end

--[[-< D A T E _ N A M E _ X L A T E >

Attempts to translate English date names to local-language date names using names supplied by MediaWiki's date parser function. This is simple name-for-name replacement and may not work for all languages.

if xlat_dig is true, this function will also translate Western (English) digits to the local language's digits. This will also translate ymd dates.

]]

local function date_name_xlate (date_parameters_list, xlt_dig) local xlate; local mode;																	-- long or short month names local modified = false; local date; local sources_t = { {cfg.date_names.en.long, cfg.date_names.inv_local_long},				-- for translating long English month names to long local month names {cfg.date_names.en.short, cfg.date_names.inv_local_short},				-- short month names {cfg.date_names.en.quarter, cfg.date_names.inv_local_quarter},			-- quarter date names {cfg.date_names.en.season, cfg.date_names.inv_local_season},			-- season date nam {cfg.date_names.en.named, cfg.date_names.inv_local_named},				-- named dates }

local function is_xlateable (month)											-- local function to get local date name that replaces existing English-language date name for _, date_names_t in ipairs (sources_t) do							-- for each sequence table in date_names_t if date_names_t[1][month] then										-- if date name is English month (long or short), quarter, season or named and if date_names_t[2][date_names_t[1][month]] then					-- if there is a matching local date name return date_names_t[2][date_names_t[1][month]];				-- return the local date name end end end end

for param_name, param_val in pairs(date_parameters_list) do					-- for each date-holding parameter in the list if is_set(param_val.val) then											-- if the parameter has a value date = param_val.val; for month in mw.ustring.gmatch (date, '[%a ]+') do					-- iterate through all date names in the date (single date or date range) month = mw.text.trim (month);									-- this because quarterly dates contain whitespace xlate = is_xlateable (month);									-- get translate ; returns translation or nil if xlate then date = mw.ustring.gsub (date, month, xlate);				-- replace the English with the translation date_parameters_list[param_name].val = date;				-- save the translated date modified = true; end end

if xlt_dig then														-- shall we also translate digits? date = date:gsub ('%d', cfg.date_names.xlate_digits);			-- translate digits from Western to 'local digits' date_parameters_list[param_name].val = date;					-- save the translated date modified = true; end end end return modified; end

--[[--< S E T _ S E L E C T E D _ M O D U L E S >--

Sets local imported functions table to same (live or sandbox) as that used by the other modules.

]]

local function set_selected_modules (cfg_table_ptr, utilities_page_ptr) add_prop_cat = utilities_page_ptr.add_prop_cat ;							-- import functions from selected Module:Citation/CS1/Utilities module is_set = utilities_page_ptr.is_set; in_array = utilities_page_ptr.in_array; set_message = utilities_page_ptr.set_message; substitute = utilities_page_ptr.substitute; wrap_style = utilities_page_ptr.wrap_style;

cfg = cfg_table_ptr;														-- import tables from selected Module:Citation/CS1/Configuration end

--[[--< A R C H I V E _ D A T E _ C H E C K >--

Compare value in |archive-date= with the timestamp in Wayback machine urls. Emits an error message with suggested date from the |archive-url= timestamp in an appropriate format when the value in |archive-date= does not match the timestamp.

this function never called when any date in a cs1|2 template has errors

error message suggests new |archive-date= value in an appropriate format specified by .  is either a caveat: when |df=dmy or |df=mdy, the reformatter leaves |access-date= and |archive-date= formats as they are. The error message suggested date is passed to the formatter as YYYY-MM-DD so when |df=dmy or |df=mdy, the format is not changed.
 * df= or cfg.global_df in that order. If  is nil, suggested date has format from |archive-date=.  There is

]]

local function archive_date_check (archive_date, archive_url_timestamp, df) local archive_date_format = 'dmy-y';										-- holds the date format of date in |archive-date; default to ymd; 'dmy' used here to spoof reformat_dates for _, v_t in ipairs ({{'dMy', 'dmy-all'}, {'Mdy', 'mdy-all'}}) do			-- is |archive-date= format dmy or mdy? if archive_date:match (patterns[v_t[1]][1]) then						-- does the pattern match? archive_date_format = cfg.keywords_xlate[v_t[2]];					-- get appropriate |df= supported keyword from the i18n translator table break; end end local dates_t = {}; dates_t['archive-date'] = {val=archive_date, name=''};						-- setup to call reformat_dates; never called when errors so unset as not needed reformat_dates (dates_t, 'dmy-y');											-- reformat |archive-date= to ymd; 'dmy' used here to spoof reformat_dates local archive_url_date = archive_url_timestamp:gsub ('(%d%d%d%d)(%d%d)(%d%d)%d*', '%1-%2-%3');	-- make ymd format date from timestamp

if dates_t['archive-date'].val == archive_url_date then						-- are the two dates the same return;																	-- yes, done else dates_t['archive-date'] = {val=archive_url_date, name=''};				-- setup to call reformat_dates with the timestamp date reformat_dates (dates_t, df or archive_date_format);					-- reformat timestamp to format specified by  or format used in |archive-date= archive_url_date = dates_t['archive-date'].val; set_message ('err_archive_date_url_ts_mismatch', archive_url_date);		-- emit an error message end end

----< E X P O R T E D  F U N C T I O N S >--

return {																		-- return exported functions archive_date_check = archive_date_check, date_hyphen_to_dash = date_hyphen_to_dash, date_name_xlate = date_name_xlate, dates = dates, reformat_dates = reformat_dates, set_selected_modules = set_selected_modules, year_date_check = year_date_check, }