Citation/CS1/Date validation
 | This Lua module is used on 2,150,000 pages. To avoid large-scale disruption and unnecessary server load, any changes to this module should first be tested in its /sandbox or /testcases subpages. The tested changes can then be added to this page in one single edit. Please consider discussing any changes on the talk page before implementing them. |
This module contains routines that support the Citation Style 1 format for citations on Wikipedia. In particular, this module contains a suite of functions that validate date formats and content for the variety of date-holding parameters associated with CS1 citations.
local p = {}
-- 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
function get_month_number (month)
local long_months = {['January']=1, ['February']=2, ['March']=3, ['April']=4, ['May']=5, ['June']=6, ['July']=7, ['August']=8, ['September']=9, ['October']=10, ['November']=11, ['December']=12};
local short_months = {['Jan']=1, ['Feb']=2, ['Mar']=3, ['Apr']=4, ['May']=5, ['Jun']=6, ['Jul']=7, ['Aug']=8, ['Sep']=9, ['Oct']=10, ['Nov']=11, ['Dec']=12};
local temp;
temp=long_months[month];
if temp then return temp; end -- if month is the long-form name
temp=short_months[month];
if temp then return temp; end -- if month is the short-form name
return 0; -- misspelled, improper case, or not a month name
end
-- returns a number according to the sequence of seasons in a year: 1 for Winter, etc. Capitalization and spelling must be correct. If not a valid season, returns 0
function get_season_number (season)
local season_list = {['Winter']=1, ['Spring']=2, ['Summer']=3, ['Fall']=4, ['Autumn']=4}
local temp;
temp=season_list[season];
if temp then return temp; end -- if season is a valid name return its number
return 0; -- misspelled, improper case, or not a season name
end
--returns true if month or season is valid (properly spelled, capitalized, abbreviated)
function is_valid_month_or_season (month_season)
if 0 == get_month_number (month_season) then -- if month text isn't one of the twelve months, might be a season
if 0 == get_season_number (month_season) then -- not a month, is it a season?
return false; -- return false not a month or one of the five seasons
end
end
return true;
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.
]]
function is_valid_year(year)
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
return tonumber(year) <= year_limit; -- false if year is in the future more than one year
end
--[[
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.
]]
function is_valid_date (year, month, day)
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) then -- no farther into the future than next year
return false;
end
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
month_length = 29;
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
--[[
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. Similarly, seasons are also left to right, earliest to latest in time. There is
an oddity with seasons. Winter is assigned a value of 1, spring 2, ..., fall and autumn 4. Because winter can follow fall/autumn at the end of a calender year, a special test
is made to see if |date=Fall-Winter yyyy (4-1) is the date.
]]
function is_valid_month_season_range(range_start, range_end)
local range_start_number = get_month_number (range_start);
if 0 == range_start_number then -- is this a month range?
local range_start_number = get_season_number (range_start); -- not a month; is it a season? get start season number
local range_end_number = get_season_number (range_end); -- get end season number
if 0 ~= range_start_number then -- is start of range a season?
if range_start_number < range_end_number then -- range_start is a season
return true; -- return true when range_end is also a season and follows start season; else false
end
if 4 == range_start_number and 1 == range_end_number then -- special case when range is Fall-Winter or Autumn-Winter
return true;
end
end
return false; -- range_start is not a month or a season; or range_start is a season and range_end is not; or improper season sequence
end
local range_end_number = get_month_number (range_end); -- get end month number
if range_start_number < range_end_number then -- range_start is a month; does range_start precede range_end?
return true; -- if yes, return true
end
return false; -- range_start month number is greater than or equal to range end number; or range end isn't a month
end
--[[
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
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, accessdate, embargo, archivedate, etc.)
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 date_string without anchor_year disambiguator if any
]]
function check_date (date_string)
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("^%d%d%d%d%-%d%d%-%d%d$") then -- year-initial numerical year month day format
year, month, day=string.match(date_string, "(%d%d%d%d)%-(%d%d)%-(%d%d)");
month=tonumber(month);
if 12 < month or 1 > month or 1583 > tonumber(year) then return false; end -- month number not valid or not Gregorian calendar
anchor_year = year;
elseif date_string:match("^%a+ +[1-9]%d?, +[1-9]%d%d%d%a?$") then -- month-initial: month day, year
month, day, anchor_year, year=string.match(date_string, "(%a+)%s*(%d%d?),%s*((%d%d%d%d)%a?)");
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 date_string:match("^%a+ +[1-9]%d?–[1-9]%d?, +[1-9]%d%d%d%a?$") then -- month-initial day range: month day–day, year; days are separated by endash
month, day, day2, anchor_year, year=string.match(date_string, "(%a+) +(%d%d?)–(%d%d?), +((%d%d%d%d)%a?)");
if tonumber(day) >= tonumber(day2) then return false; end -- date range order is left to right: earlier to later; dates may not be the same;
month = get_month_number (month);
if 0 == month then return false; end -- return false if month text isn't one of the twelve months
elseif date_string:match("^[1-9]%d? +%a+ +[1-9]%d%d%d%a?$") then -- day-initial: day month year
day, month, anchor_year, year=string.match(date_string, "(%d%d*)%s*(%a+)%s*((%d%d%d%d)%a?)");
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 date_string:match("^[1-9]%d?–[1-9]%d? +%a+ +[1-9]%d%d%d%a?$") then -- day-range-initial: day–day month year; days are separated by endash
day, day2, month, anchor_year, year=string.match(date_string, "(%d%d?)–(%d%d?) +(%a+) +((%d%d%d%d)%a?)");
if tonumber(day) >= tonumber(day2) then return false; end -- date range order is left to right: earlier to later; dates may not be the same;
month = get_month_number (month);
if 0 == month then return false; end -- return false if month text isn't one of the twelve months
elseif date_string:match("^[1-9]%d? +%a+ – [1-9]%d? +%a+ +[1-9]%d%d%d%a?$") then -- day initial month-day-range: day month - day month year; uses spaced endash
day, month, day2, month2, anchor_year, year=date_string:match("(%d%d?) +(%a+) – (%d%d?) +(%a+) +((%d%d%d%d)%a?)");
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);
month2 = get_month_number (month2);
elseif date_string:match("^%a+ +[1-9]%d? – %a+ +[1-9]%d?, +[1-9]%d%d%d?%a?$") then -- month initial month-day-range: month day – month day, year; uses spaced endash
month, day, month2, day2, anchor_year, year=date_string:match("(%a+) +(%d%d?) – (%a+) +(%d%d?), +((%d%d%d%d)%a?)");
if (not is_valid_month_season_range(month, month2)) or not is_valid_year(year) then return false; end
month = get_month_number (month);
month2 = get_month_number (month2);
elseif date_string:match("^[1-9]%d? +%a+ +[1-9]%d%d%d – [1-9]%d? +%a+ +[1-9]%d%d%d%a?$") then -- day initial month-day-year-range: day month year - day month year; uses spaced endash
day, month, year, day2, month2, anchor_year, year2=date_string:match("(%d%d?) +(%a+) +(%d%d%d%d?) – (%d%d?) +(%a+) +((%d%d%d%d?)%a?)");
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) then return false; end -- year2 no more than one year in the future
month = get_month_number (month);
month2 = get_month_number (month2);
elseif date_string:match("^%a+ +[1-9]%d?, +[1-9]%d%d%d – %a+ +[1-9]%d?, +[1-9]%d%d%d%a?$") then -- month initial month-day-year-range: month day, year – month day, year; uses spaced endash
month, day, year, month2, day2, anchor_year, year2=date_string:match("(%a+) +(%d%d?), +(%d%d%d%d) – (%a+) +(%d%d?), +((%d%d%d%d)%a?)");
if tonumber(year2) <= tonumber(year) then return false; end -- must be sequential years, left to right, earlier to later
if not is_valid_year(year2) then return false; end -- year2 no more than one year in the future
month = get_month_number (month);
month2 = get_month_number (month2);
elseif date_string:match("^%a+ +[1-9]%d%d%d–%d%d%a?$") then -- special case Winter/Summer year-year (YYYY-YY); year separated with unspaced endash
if nil == date_string:match("^Winter") and nil == date_string:match("^Summer") then return false end; -- 'month' can only be Winter or Summer
local century;
year, century, anchor_year, year2=date_string:match("%a+ +((%d%d)%d%d)–((%d%d)%a?)");
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
elseif date_string:match("^%a+ +[1-9]%d%d%d–[1-9]%d%d%d%a?$") then -- special case Winter/Summer year-year; year separated with unspaced endash
if nil == date_string:match("^Winter") and nil == date_string:match("^Summer") then return false end; -- 'month' can only be Winter or Summer
year, anchor_year, year2=date_string:match("%a+ +(%d%d%d%d)–((%d%d%d%d)%a?)");
anchor_year=year..'–'..anchor_year; -- assemble anchor_year from both years
if 1 ~= tonumber(year2) - tonumber(year) then return false; end -- must be sequential years, left to right, earlier to later
if not is_valid_year(year2) then return false; end -- no year farther in the future than next year
elseif date_string:match("^%a+ +[1-9]%d%d%d% – %a+ +[1-9]%d%d%d%a?$") then -- month/season year - month/season year; separated by spaced endash
month, year, month2, anchor_year, year2=date_string:match("(%a+) +(%d%d%d%d) – (%a+) +((%d%d%d%d)%a?)");
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 not((0 ~= get_month_number(month) and 0 ~= get_month_number(month2)) or -- both must be month year or season year, not mixed
(0 ~= get_season_number(month) and 0 ~= get_season_number(month2))) then return false; end
elseif date_string:match ("^%a+–%a+ +[1-9]%d%d%d%a?$") then -- month/season range year; months separated by endash
month, month2, anchor_year, year=date_string:match ("(%a+)–(%a+)%s*((%d%d%d%d)%a?)");
if (not is_valid_month_season_range(month, month2)) or (not is_valid_year(year)) then
return false;
end
elseif date_string:match("^%a+ +%d%d%d%d%a?$") then -- month/season year
month, anchor_year, year=date_string:match("(%a+)%s*((%d%d%d%d)%a?)");
if not is_valid_year(year) then return false; end
if not is_valid_month_or_season (month) then return false; end
elseif date_string:match("^[1-9]%d%d%d?–[1-9]%d%d%d?%a?$") then -- Year range: YYY-YYY or YYY-YYYY or YYYY–YYYY; separated by unspaced endash; 100-9999
year, anchor_year, year2=date_string:match("(%d%d%d%d?)–((%d%d%d%d?)%a?)");
anchor_year=year..'–'..anchor_year; -- assemble anchor year from both years
if tonumber(year) >= tonumber(year2) then return false; end -- left to right, earlier to later, not the same
if not is_valid_year(year2) then return false; end -- no year farther in the future than next year
elseif date_string:match("^[1-9]%d%d%d–%d%d%a?$") then -- Year range: YYYY–YY; separated by unspaced endash
local century;
year, century, anchor_year, year2=date_string:match("((%d%d)%d%d)–((%d%d)%a?)");
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
elseif date_string:match("^[1-9]%d%d%d?%a?$") then -- year; here accept either YYY or YYYY
anchor_year, year=date_string:match("((%d%d%d%d?)%a?)");
if false == is_valid_year(year) then
return false;
end
else
return false; -- date format not one of the MOS:DATE approved formats
end
local result=true; -- check whole dates for validity; assume true because not all dates will go through this test
if 0 ~= year and 0 ~= month and 0 ~= day and 0 == year2 and 0 == month2 and 0 == day2 then -- YMD (simple whole date)
result=is_valid_date(year,month,day);
elseif 0 ~= year and 0 ~= month and 0 ~= day and 0 == year2 and 0 == month2 and 0 ~= day2 then -- YMD-d (day range)
result=is_valid_date(year,month,day);
result=result and is_valid_date(year,month,day2);
elseif 0 ~= year and 0 ~= month and 0 ~= day and 0 == year2 and 0 ~= month2 and 0 ~= day2 then -- YMD-md (day month range)
result=is_valid_date(year,month,day);
result=result and is_valid_date(year,month2,day2);
elseif 0 ~= year and 0 ~= month and 0 ~= day and 0 ~= year2 and 0 ~= month2 and 0 ~= day2 then -- YMD-ymd (day month year range)
result=is_valid_date(year,month,day);
result=result and is_valid_date(year2,month2,day2);
end
if false == result then return false; end
-- if here, then date_string is valid; get coins_date from date_string (leave CITEREF disambiguator) ...
coins_date=date_string:match("^(.+%d)%a?$"); -- last character of valid disambiguatable date is always a digit
coins_date= mw.ustring.gsub(coins_date, "–", "-" ); -- ... and replace any ndash with a hyphen
return true, anchor_year, coins_date; -- 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,
a single error message is created as the dates are tested.
]]
function p.dates(date_parameters_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 error_message ="";
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) then -- if the parameter has a value
if v:match("^c%. [1-9]%d%d%d?%a?$") then -- special case for c. year or with or without CITEREF disambiguator - only |date= and |year=
local year = v:match("c%. ([1-9]%d%d%d?)%a?"); -- get the year portion so it can be tested
if 'date'==k then
anchor_year, COinS_date = v:match("((c%. [1-9]%d%d%d?)%a?)"); -- anchor year and COinS_date only from |date= parameter
good_date = is_valid_year(year);
elseif 'year'==k then
good_date = is_valid_year(year);
end
elseif 'date'==k then -- if the parameter is |date=
if v:match("^n%.d%.%a?") then -- if |date=n.d. with or without a CITEREF disambiguator
good_date, anchor_year, COinS_date = true, v:match("((n%.d%.)%a?)"); --"n.d."; no error when date parameter is set to no date
elseif v:match("^nd%a?$") then -- if |date=nd with or without a CITEREF disambiguator
good_date, anchor_year, COinS_date = true, v:match("((nd)%a?)"); --"nd"; no error when date parameter is set to no date
else
good_date, anchor_year, COinS_date = check_date (v); -- go test the date
end
else -- any other date-holding parameter
good_date = check_date (v); -- go test the date
end
if false==good_date then -- assemble one error message so we don't add the tracking category multiple times
if is_set(error_message) then -- once we've added the first portion of the error message ...
error_message=error_message .. ", "; -- ... add a comma space separator
end
error_message=error_message .. "|" .. k .. "="; -- add the failed parameter
end
end
end
return anchor_year, COinS_date, error_message; -- and done
end
return p;