Difference between revisions of "Module:Citation/CS1/Date validation"

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local p = {}
+
--[[--------------------------< F O R W A R D  D E C L A R A T I O N S >--------------------------------------
 +
]]
 +
 
 +
local is_set, in_array; -- imported functions from selected Module:Citation/CS1/Utilities
 +
local cfg; -- table of tables imported from selected Module:Citation/CS1/Configuration
 +
 
 +
 
 +
--[=[-------------------------< 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 |accessdate= 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-Engish 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 lang = mw.getContentLanguage();
 +
local good1, good2;
 +
local access_ts, tomorrow_ts; -- to hold unix time stamps representing the dates
 +
 +
good1, access_ts = pcall( lang.formatDate, lang, 'U', accessdate ); -- convert accessdate value to unix timesatmp
 +
good2, tomorrow_ts = pcall( lang.formatDate, lang, '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:parseFormattedNumber (access_ts); -- convert to numbers for the comparison;
 +
tomorrow_ts = tonumber (tomorrow_ts) or lang:parseFormattedNumber (tomorrow_ts);
 +
else
 +
return false; -- one or both failed to convert to unix time stamp
 +
end
  
-- 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
+
if 979516800 <= access_ts and access_ts < tomorrow_ts then -- Wikipedia start date <= accessdate < tomorrow's date
function get_month_number (month)
+
return true;
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};
+
else
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};
+
return false; -- accessdate out of range
local temp;
+
end
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
 
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)
+
--[[--------------------------< G E T _ M O N T H _ N U M B E R >----------------------------------------------
local season_list = {['Winter']=1, ['Spring']=2, ['Summer']=3, ['Fall']=4, ['Autumn']=4}
+
 
local temp;
+
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
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
+
 
 +
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
 
end
 +
 +
 +
--[[--------------------------< 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 |embargo= is
 +
set, the editor intended to embargo a pmc but |embargo= does not hold a single date.
 +
 +
]]
 +
 +
local function is_valid_embargo_date (v)
 +
if v:match ('^%d%d%d%d%-%d%d%-%d%d$') or -- ymd
 +
v:match ('^%d%d?%s+%a+%s+%d%d%d%d$') or -- dmy
 +
v:match ('^%a+%s+%d%d?%s*,%s*%d%d%d%d$') 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
 +
 +
 +
--[[--------------------------< 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: 1 for Winter, etc.  Capitalization and spelling must be correct. If not a valid season, returns 0
 +
 +
Uses ISO DIS 8601 2016 part 2 §4.7  Divisions of a year for hemishpere-independent seasons:
 +
21-24 = Spring, Summer, Autumn, Winter, independent of “Hemisphere”
 +
 +
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)
 +
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
 +
 +
 +
--[[--------------------------< I S _ P R O P E R _ N A M E >--------------------------------------------------
 +
 +
returns a non-zero number if date contains a recognized proper name.  Capitalization and spelling must be correct.
 +
 +
]]
 +
 +
local function is_proper_name (name)
 +
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
 +
 +
 +
--[[--------------------------< I S _ V A L I D _ M O N T H _ O R _ S E A S O N >------------------------------
  
 
--returns true if month or season is valid (properly spelled, capitalized, abbreviated)
 
--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
+
local 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
 
end
 
end
Line 34: Line 133:
  
  
-- 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.
+
--[[--------------------------< I S _ V A L I D _ Y E A R >----------------------------------------------------
function is_valid_year(year)
+
 
 +
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.
 +
 
 +
]]
 +
local year_limit;
 +
local function is_valid_year(year)
 
if not is_set(year_limit) then
 
if not is_set(year_limit) then
year_limit = tonumber(os.date("%Y"))+1; -- global variable so we only have to fetch it once (os.date("Y") no longer works?)
+
year_limit = tonumber(os.date("%Y"))+1; -- global variable so we only have to fetch it once
 
end
 
end
return tonumber(year) <= year_limit; -- false if year is in the future more than one year
+
return tonumber(year) <= year_limit; -- false if year is in the future more than one year
 
end
 
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.
+
--[[--------------------------< I S _ V A L I D _ D A T E >----------------------------------------------------
Where the two calendars overlap (1582 to approximately 1923) dates are assumed to be Gregorian.
+
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 function is_valid_date (year, month, day)
 
local days_in_month = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
 
local days_in_month = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
 
local month_length;
 
local month_length;
if not is_valid_year(year) then -- no farther into the future than next year
+
if not is_valid_year(year) then -- no farther into the future than next year
 
return false;
 
return false;
 
end
 
end
 
 
if (2==month) then -- if February
+
month = tonumber(month); -- required for YYYY-MM-DD dates
month_length = 28; -- then 28 days unless
+
if 1582 > tonumber(year) then -- Julian calendar
+
if (2==month) then -- if February
if 0==(year%4) then
+
month_length = 28; -- then 28 days unless
month_length = 29;
+
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
 
end
else -- Gregorian calendar
+
else -- Gregorian calendar
if (0==(year%4) and (0~=(year%100) or 0==(year%400))) then -- is a leap year?
+
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
+
month_length = 29; -- if leap year then 29 days in February
 
end
 
end
 
end
 
end
Line 76: Line 187:
 
end
 
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.
 +
There is a special test for May because it can be either short or long form.
 +
 
 +
Returns true when style for both months is the same
 +
 
 +
]]
 +
 
 +
local function is_valid_month_range_style (month1, month2)
 +
local len1 = month1:len();
 +
local len2 = month2:len();
 +
if len1 == len2 then
 +
return true; -- both months are short form so return true
 +
elseif 'May' == month1 or 'May'== month2 then
 +
return true; -- both months are long form so return true
 +
elseif 3 == len1 or 3 == len2 then
 +
return false; -- months are mixed form so return false
 +
else
 +
return true; -- both months are long form so return true
 +
end
 +
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.
 
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
+
Month pairs are expected to be left to right, earliest to latest in time.
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.
+
All season ranges are accepted as valid because there are publishers out there who have published a Summer–Spring YYYY issue so ... ok
 +
 
 
]]
 
]]
  
function is_valid_month_season_range(range_start, range_end)
+
local function is_valid_month_season_range(range_start, range_end)
 
local range_start_number = get_month_number (range_start);
 
local range_start_number = get_month_number (range_start);
 +
local range_end_number;
 
 
if 0 == range_start_number then -- is this a month range?
+
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
+
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
+
range_end_number = get_season_number (range_end); -- get end season number
 +
 
 +
if (0 ~= range_start_number) and (0 ~= range_end_number) then
 +
return true; -- any season pairing is accepted
 +
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 then -- range_start is a month; does range_start precede range_end?
 +
if is_valid_month_range_style (range_start, range_end) then -- do months have the same style?
 +
return true; -- proper order and same style
 +
end
 +
end
 +
return false; -- range_start month number is greater than or equal to range end number; or range end isn't a month
 +
end
  
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
+
--[[--------------------------< M A K E _ C O I N S _ D A T E >------------------------------------------------
return true; -- return true when range_end is also a season and follows start season; else false
+
 
end
+
This function receives a table of date parts for one or two dates and an empty table reference declared in
if 4 == range_start_number and 1 == range_end_number then -- special case when range is Fall-Winter or Autumn-Winter
+
Module:Citation/CS1.  The function is called only for |date= parameters and only if the |date=<value> is
return true;
+
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 IS8601 formatted date
 +
rftchron: a free-form version of the date, usually without year which is in rftdate (season ranges and propername dates)
 +
rftssn: one of four season keywords: winter, spring, summer, fall (lowercase)
 +
 
 +
]]
 +
 
 +
local function make_COinS_date (input, tCOinS_date)
 +
local date; -- one date or first date in a range
 +
local date2 = ''; -- end of range date
 +
-- start temporary Julian / Gregorian calendar uncertainty detection
 +
local year = tonumber(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 / Gergorian calendar uncertainty detection
 +
 +
if 1582 > tonumber(input.year) or 20 < tonumber(input.month) then -- Julian calendar or season so &rft.date gets year only
 +
date = input.year;
 +
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', tonumber(input.year), tonumber(input.year2)) -- assemble the date range
 +
end
 +
if 20 < tonumber(input.month) then -- if season or propername date
 +
local season = {[24]='winter', [21]='spring', [22]='summer', [23]='fall', [99]='Christmas'}; -- seasons lowercase, no autumn; proper names use title case
 +
if 0 == input.month2 then -- single season date
 +
if 30 <tonumber(input.month) then
 +
tCOinS_date.rftchron = season[input.month]; -- proper name dates
 +
else
 +
tCOinS_date.rftssn = season[input.month]; -- seasons
 +
end
 +
else -- season range with a second season specified
 +
if input.year ~= input.year2 then -- season year – season year range or season year–year
 +
tCOinS_date.rftssn = season[input.month]; -- start of range season; keep this?
 +
if 0~= input.month2 then
 +
tCOinS_date.rftchron = string.format ('%s %s – %s %s', season[input.month], input.year, season[input.month2], input.year2);
 +
end
 +
else -- season–season year range
 +
tCOinS_date.rftssn = season[input.month]; -- start of range season; keep this?
 +
tCOinS_date.rftchron = season[input.month] .. '–' .. season[input.month2]; -- season–season year range
 +
end
 
end
 
end
 
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
+
tCOinS_date.rftdate = date;
 +
return; -- done
 +
end
 +
 +
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
 
end
  
local range_end_number = get_month_number (range_end); -- get end month number
+
if 0 ~= input.year2 then
if range_start_number < range_end_number then -- range_start is a month; does range_start precede range_end?
+
if 0 ~= input.day2 then
return true; -- if yes, return true
+
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
 
end
return false; -- range_start month number is greater than or equal to range end number; or range end isn't a month
+
 +
tCOinS_date.rftdate = date .. date2; -- date2 has the '/' separator
 +
return;
 
end
 
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 fomat tests, this function returns false and does not return values for anchor_year and COinS_date.  When this happens, the date parameter is
+
--[[--------------------------< P A T T E R N S >--------------------------------------------------------------
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.
+
 
 +
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
 +
['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
 +
}
 +
 
 +
 
 +
--[[--------------------------< 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 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:
 
Inputs:
date_string - date string from date-holding parameters (date, year, accessdate, embargo, archivedate, etc)
+
date_string - date string from date-holding parameters (date, year, accessdate, embargo, archivedate, etc.)
  
 
Returns:
 
Returns:
Line 124: Line 410:
 
true, anchor_year, COinS_date
 
true, anchor_year, COinS_date
 
anchor_year can be used in CITEREF anchors
 
anchor_year can be used in CITEREF anchors
COinS_date is date_string without anchor_year disambiguator if any
+
COinS_date is ISO 8601 format date; see make_COInS_date()
 +
 
 
]]
 
]]
function check_date (date_string)
+
 
 +
local function check_date (date_string, tCOinS_date, test_accessdate)
 
local year; -- assume that year2, months, and days are not used;
 
local year; -- assume that year2, months, and days are not used;
 
local year2=0; -- second year in a year range
 
local year2=0; -- second year in a year range
Line 136: Line 424:
 
local coins_date;
 
local coins_date;
  
if date_string:match("^%d%d%d%d%-%d%d%-%d%d$") then -- year-initial numerical year month day format
+
if date_string:match (patterns['ymd'][1]) then -- year-initial numerical year month day format
year, month, day=string.match(date_string, "(%d%d%d%d)%-(%d%d)%-(%d%d)");
+
year, month, day=date_string:match (patterns['ymd'][1]);
month=tonumber(month);
+
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
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;
 
anchor_year = year;
 
+
elseif date_string:match("^%a+ +[1-9]%d?, +[1-9]%d%d%d%a?$") then -- month-initial: month day, year
+
elseif mw.ustring.match(date_string, patterns['Mdy'][1]) 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, day, anchor_year, year=mw.ustring.match(date_string, patterns['Mdy'][1]);
 
month = get_month_number (month);
 
month = get_month_number (month);
if 0 == month then return false; end -- return false if month text isn't one of the twelve months
+
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
+
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=string.match(date_string, "(%a+) +(%d%d?)–(%d%d?), +((%d%d%d%d)%a?)");
+
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;
+
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);
 
month = get_month_number (month);
if 0 == month then return false; end -- return false if month text isn't one of the twelve months
+
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
+
--[[ NOT supported at en.wiki
day, month, anchor_year, year=string.match(date_string, "(%d%d*)%s*(%a+)%s*((%d%d%d%d)%a?)");
+
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);
 
month = get_month_number (month);
if 0 == month then return false; end -- return false if month text isn't one of the twelve months
+
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 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
+
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=string.match(date_string, "(%d%d?)–(%d%d?) +(%a+) +((%d%d%d%d)%a?)");
+
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;
+
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);
 
month = get_month_number (month);
if 0 == month then return false; end -- return false if month text isn't one of the twelve months
+
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 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
+
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=date_string:match("(%d%d?) +(%a+) – (%d%d?) +(%a+) +((%d%d%d%d)%a?)");
+
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;
 
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);
+
month = get_month_number (month); -- for metadata
 
month2 = get_month_number (month2);
 
month2 = get_month_number (month2);
 +
year2=year;
  
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
+
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=date_string:match("(%a+) +(%d%d?) – (%a+) +(%d%d?), +((%d%d%d%d)%a?)");
+
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)) or not is_valid_year(year) then return false; end
 
if (not is_valid_month_season_range(month, month2)) or not is_valid_year(year) then return false; end
month = get_month_number (month);
+
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);
 +
 
 +
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);
 
month2 = get_month_number (month2);
  
elseif date_string:match("^Winter +[1-9]%d%d%d–[1-9]%d%d%d%a?$") then -- special case Winter year-year; year separated with unspaced endash
+
elseif mw.ustring.match(date_string, patterns['Sy4-y2'][1]) then -- special case Winter/Summer year-year (YYYY-YY); year separated with unspaced endash
year, anchor_year, year2=date_string:match("Winter +(%d%d%d%d)((%d%d%d%d)%a?)");
+
local century;
anchor_year=year..'–'..anchor_year; -- assemble anchor_year from both years
+
month, year, century, anchor_year, year2=mw.ustring.match(date_string, patterns['Sy4-y2'][1]);
if 1 ~= tonumber(year2) - tonumber(year) then return false; end -- must be sequential years, left to right, earlier to later
+
if 'Winter' ~= month and 'Summer' ~= month then return false end; -- 'month' can only be Winter or Summer
if not is_valid_year(year2) then return false; end -- no year farther in the future than next year
+
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);
 +
 
 +
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]);
 +
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
 +
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); -- for metadata
  
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
+
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=date_string:match("(%a+) +(%d%d%d%d) – (%a+) +((%d%d%d%d)%a?)");
+
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
+
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 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 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
+
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
(0 ~= get_season_number(month) and 0 ~= get_season_number(month2))) then return false; end
+
month = get_month_number(month);
 +
month2 = get_month_number(month2);
 +
elseif 0 ~= get_season_number(month) and 0 ~= get_season_number(month2) then -- both must be or season year, not mixed
 +
month = get_season_number(month);
 +
month2 = get_season_number(month2);
 +
else
 +
return false;
 +
end
  
elseif date_string:match ("^%a+–%a+ +[1-9]%d%d%d%a?$") then -- month/season range year; months separated by endash  
+
elseif mw.ustring.match(date_string, patterns['M-My'][1]) 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?)");
+
month, month2, anchor_year, year=mw.ustring.match(date_string, patterns['M-My'][1]);
if (not is_valid_month_season_range(month, month2)) or (not is_valid_year(year)) then
+
if (not is_valid_month_season_range(month, month2)) or (not is_valid_year(year)) then return false; end
return false;
+
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);
 +
else
 +
month = get_season_number(month);
 +
month2 = get_season_number(month2);
 
end
 
end
 +
year2=year;
 
 
elseif date_string:match("^%a+ +%d%d%d%d%a?$") then -- month/season year
+
elseif mw.ustring.match(date_string, patterns['My'][1]) then -- month/season year or proper-name year
month, anchor_year, year=date_string:match("(%a+)%s*((%d%d%d%d)%a?)");
+
month, anchor_year, year=mw.ustring.match(date_string, patterns['My'][1]);
 
if not is_valid_year(year) then return false; end
 
if not is_valid_year(year) then return false; end
if not is_valid_month_or_season (month) then return false; end
+
if not is_valid_month_or_season (month) and 0 == is_proper_name (month) 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);
 +
elseif 0 ~= get_season_number(month) then
 +
month = get_season_number(month);
 +
else
 +
month = is_proper_name (month); -- must be proper name; not supported in COinS
 +
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
+
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=date_string:match("(%d%d%d%d?)–((%d%d%d%d?)%a?)");
+
year, anchor_year, year2=mw.ustring.match(date_string, patterns['y-y'][1]);
 
anchor_year=year..'–'..anchor_year; -- assemble anchor year from both years
 
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 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 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
+
elseif mw.ustring.match(date_string, patterns['y4-y2'][1]) then -- Year range: YYYY–YY; separated by unspaced endash
 
local century;
 
local century;
year, century, anchor_year, year2=date_string:match("((%d%d)%d%d)–((%d%d)%a?)");
+
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
 
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
 
if 13 > tonumber(year2) then return false; end -- don't allow 2003-05 which might be May 2003
Line 216: Line 562:
 
if not is_valid_year(year2) then return false; end -- no year farther in the future than next year
 
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
+
elseif date_string:match (patterns['y'][1]) then -- year; here accept either YYY or YYYY
anchor_year, year=date_string:match("((%d%d%d%d?)%a?)");
+
anchor_year, year=date_string:match (patterns['y'][1]);
 
if false == is_valid_year(year) then
 
if false == is_valid_year(year) then
 
return false;
 
return false;
Line 223: Line 569:
  
 
else
 
else
return false; -- date format not one of the MOS:DATE approved formats
+
return false; -- date format not one of the MOS:DATE approved formats
 +
end
 +
 
 +
if test_accessdate then -- test accessdate 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; accessdate must not be a range
 +
if not is_valid_accessdate (year..'-'..month..'-'..day) then
 +
return false; -- return false when accessdate out of bounds
 +
end
 +
else
 +
return false; -- return false when accessdate is a range of two dates
 +
end
 
end
 
end
  
local result=true; -- check whole dates for validity; assume true because not all dates will go through this test
+
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)
 
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);
 
result=is_valid_date(year,month,day);
Line 244: Line 601:
 
 
 
if false == result then return false; 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
+
if nil ~= tCOinS_date then -- this table only passed into this function when testing |date= parameter values
coins_date= mw.ustring.gsub(coins_date, "–", "-" ); -- ... and replace any ndash with a hyphen
+
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, coins_date; -- format is good and date string represents a real date
+
return true, anchor_year; -- format is good and date string represents a real date
 
end
 
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
 
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
 
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
Line 258: Line 618:
 
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,
 
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.
 
a single error message is created as the dates are tested.
 +
 
]]
 
]]
  
function p.dates(date_parameters_list)
+
local function dates(date_parameters_list, tCOinS_date)
 
local anchor_year; -- will return as nil if the date being tested is not |date=
 
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 COinS_date; -- will return as nil if the date being tested is not |date=
local error_message ="";
+
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;
+
local error_message = "";
 +
local good_date = false;
 
 
for k, v in pairs(date_parameters_list) do -- for each date-holding parameter in the list
+
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 is_set(v.val) then -- if the parameter has a value
if v:match("^c%. [1-9]%d%d%d?%a?$") then -- special case for c. year or with or without CITEREF disambiguator - only |date= and |year=
+
v.val = mw.ustring.gsub (v.val, '%d', cfg.date_names.local_digits); -- translate 'local' digits to Western 0-9
local year = v:match("c%. ([1-9]%d%d%d?)%a?"); -- get the year portion so it can be tested
+
if v.val:match("^c%. [1-9]%d%d%d?%a?$") 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
 
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
+
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);
 
good_date = is_valid_year(year);
 
elseif 'year'==k then
 
elseif 'year'==k then
 
good_date = is_valid_year(year);
 
good_date = is_valid_year(year);
 
end
 
end
elseif 'date'==k then -- if the parameter is |date=
+
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
+
if v.val:match("^n%.d%.%a?$") then -- if |date=n.d. with or without a CITEREF disambiguator
good_date, anchor_year, COinS_date = true, v:match("((n%.d%.)%a?)"); --"n.d."; no error when date parameter is set to no date
+
good_date, anchor_year, COinS_date = true, v.val:match("((n%.d%.)%a?)"); --"n.d."; no error when date parameter is set to no date
elseif v:match("nd%a?$") then -- if |date=nd with or without a CITEREF disambiguator
+
elseif v.val: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
+
good_date, anchor_year, COinS_date = true, v.val:match("((nd)%a?)"); --"nd"; no error when date parameter is set to no date
 
else
 
else
good_date, anchor_year, COinS_date = check_date (v); -- go test the date
+
good_date, anchor_year, COinS_date = check_date (v.val, 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 'access-date'==k then -- if the parameter is |date=
 +
good_date = check_date (v.val, nil, true); -- go test the date; nil is a placeholder; true is the test_accessdate flag
 +
elseif 'embargo'==k then -- if the parameter is |embargo=
 +
good_date = check_date (v.val); -- 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 |embargo= date a single dmy, mdy, or ymd formatted date? yes:returns embargo; no: returns 9999
 +
end
 +
else -- any other date-holding parameter
 +
good_date = check_date (v.val); -- 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 .. "&#124;" .. v.name .. "="; -- add the failed parameter
 +
end
 +
end
 +
end
 +
return anchor_year, embargo_date, error_message; -- 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 returns a 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)
 +
 
 +
]]
 +
 
 +
local function year_date_check (year_string, date_string)
 +
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
 +
result = 0; -- no recognizable year in date
 +
end
 +
return result;
 +
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 patern_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
 +
 
 +
-- if 'yMd' == format_param and in_array (pattern_idx, {'yMd', 'Md-dy', 'd-dMy', 'dM-dMy', 'Md-Mdy', 'dMy-dMy', 'Mdy-Mdy'}) then -- not supported at en.wiki
 +
if 'yMd' == format_param then -- not supported at en.wiki
 +
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 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_s'][tonumber(t.m)]; -- convert it to a month name
 +
else
 +
t.m = cfg.date_names['inv_local_l'][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
 +
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_s'][t[mon]]) or cfg.date_names['inv_local_l'][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 {{use xxx dates}} templates.  If found, xxx becomes the global date format as xxx-all.  If |cs1-dates= in
 +
{{use xxx dates}} 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 {{use xxx dates}} 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 {{use xxx dates}};
 +
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 {{use xxx dates}}
 +
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
 +
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) then
 +
if not mw.ustring.match (param_val.val, '%d%d%d%d%-%d%d%-%d%d') 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
else -- any other date-holding parameter
 
good_date = check_date (v); -- go test the date
 
 
end
 
end
if false==good_date then -- assemble one error message so we don't add the tracking category multiple times
+
end
if is_set(error_message) then -- once we've added the first portion of the error message ...
+
end
error_message=error_message .. ", "; -- ... add a comma space separator
+
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 month names to local-language month 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;
 +
 +
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 dates in the date (single date or date range)
 +
if cfg.date_names.en.long[month] then
 +
mode = 'F'; -- English name is long so use long local name
 +
elseif cfg.date_names.en.short[month] then
 +
mode = 'M'; -- English name is short so use short local name
 +
else
 +
mode = nil; -- not an English month name; could be local language month name or an English season name
 +
end
 +
 +
if mode then -- might be a season
 +
xlate = mw.getContentLanguage():formatDate(mode, '1' .. month); -- translate the month name to this local language
 +
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
error_message=error_message .. "&#124;" .. k .. "="; -- add the failed parameter
+
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
 
end
 +
end
 +
 +
return modified;
 
end
 
end
  
return anchor_year, COinS_date, error_message; -- and done
+
 
 +
--[[--------------------------< 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)
 +
is_set = utilities_page_ptr.is_set; -- import functions from selected Module:Citation/CS1/Utilities module
 +
in_array = utilities_page_ptr.in_array; -- import functions from selected Module:Citation/CS1/Utilities module
 +
cfg = cfg_table_ptr; -- import tables from selected Module:Citation/CS1/Configuration
 
end
 
end
  
return p;
+
 
 +
--[[--------------------------< E X P O R T E D  F U N C T I O N S >------------------------------------------
 +
]]
 +
 
 +
return { -- return exported functions
 +
dates = dates,
 +
year_date_check = year_date_check,
 +
reformat_dates = reformat_dates,
 +
date_hyphen_to_dash = date_hyphen_to_dash,
 +
date_name_xlate = date_name_xlate,
 +
set_selected_modules = set_selected_modules
 +
}

Latest revision as of 05:27, 24 September 2019

Documentation for this module may be created at Module:Citation/CS1/Date validation/doc


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

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


--[=[-------------------------< 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 |accessdate= 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-Engish 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 lang = mw.getContentLanguage();
	local good1, good2;
	local access_ts, tomorrow_ts;												-- to hold unix time stamps representing the dates
		
	good1, access_ts = pcall( lang.formatDate, lang, 'U', accessdate );			-- convert accessdate value to unix timesatmp 
	good2, tomorrow_ts = pcall( lang.formatDate, lang, '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:parseFormattedNumber (access_ts);			-- convert to numbers for the comparison;
		tomorrow_ts = tonumber (tomorrow_ts) or lang: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


--[[--------------------------< 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 |embargo= is
set, the editor intended to embargo a pmc but |embargo= does not hold a single date.

]]

local function is_valid_embargo_date (v)
	if v:match ('^%d%d%d%d%-%d%d%-%d%d$') or									-- ymd
		v:match ('^%d%d?%s+%a+%s+%d%d%d%d$') or									-- dmy
		v:match ('^%a+%s+%d%d?%s*,%s*%d%d%d%d$') 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


--[[--------------------------< 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: 1 for Winter, etc.  Capitalization and spelling must be correct. If not a valid season, returns 0

Uses ISO DIS 8601 2016 part 2 §4.7  Divisions of a year for hemishpere-independent seasons:
	21-24 = Spring, Summer, Autumn, Winter, independent of “Hemisphere”

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)
	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


--[[--------------------------< I S _ P R O P E R _ N A M E >--------------------------------------------------

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

]]

local function is_proper_name (name)
	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


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

--returns true if month or season is valid (properly spelled, capitalized, abbreviated)

]]

local 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.

]]
local year_limit;
local 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


--[[--------------------------< 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)
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
	
	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. 
There is a special test for May because it can be either short or long form.

Returns true when style for both months is the same

]]

local function is_valid_month_range_style (month1, month2)
local len1 = month1:len();
local len2 = month2:len();
	if len1 == len2 then
		return true;															-- both months are short form so return true
	elseif 'May' == month1 or 'May'== month2 then
		return true;															-- both months are long form so return true
	elseif 3 == len1 or 3 == len2 then
		return false;															-- months are mixed form so return false
	else
		return true;															-- both months are long form so return true
	end
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 so ... ok

]]

local function is_valid_month_season_range(range_start, range_end)
	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);					-- not a month; is it a season? get start season number
		range_end_number = get_season_number (range_end);						-- get end season number

		if (0 ~= range_start_number) and (0 ~= range_end_number) then
			return true;														-- any season pairing is accepted
		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 then								-- range_start is a month; does range_start precede range_end?
		if is_valid_month_range_style (range_start, range_end) then				-- do months have the same style?
			return true;														-- proper order and same style
		end
	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=<value> 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 IS8601 formatted date
	rftchron:	a free-form version of the date, usually without year which is in rftdate (season ranges and propername dates)
	rftssn:		one of four season keywords: winter, spring, summer, fall (lowercase)

]]

local function make_COinS_date (input, tCOinS_date)
	local date;																	-- one date or first date in a range
	local date2 = '';															-- end of range date
-- start temporary Julian / Gregorian calendar uncertainty detection
	local year = tonumber(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 / Gergorian calendar uncertainty detection
	
	if 1582 > tonumber(input.year) or 20 < tonumber(input.month) then			-- Julian calendar or season so &rft.date gets year only
		date = input.year;
		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', tonumber(input.year), tonumber(input.year2))		-- assemble the date range
		end
		if 20 < tonumber(input.month) then										-- if season or propername date
			local season = {[24]='winter', [21]='spring', [22]='summer', [23]='fall', [99]='Christmas'};	-- seasons lowercase, no autumn; proper names use title case
			if 0 == input.month2 then											-- single season date
				if 30 <tonumber(input.month) then
					tCOinS_date.rftchron = season[input.month];					-- proper name dates
				else
					tCOinS_date.rftssn = season[input.month];					-- seasons
				end
			else																-- season range with a second season specified
				if input.year ~= input.year2 then								-- season year – season year range or season year–year
					tCOinS_date.rftssn = season[input.month];					-- start of range season; keep this?
					if 0~= input.month2 then
						tCOinS_date.rftchron = string.format ('%s %s – %s %s', season[input.month], input.year, season[input.month2], input.year2);
					end
				else															-- season–season year range
					tCOinS_date.rftssn = season[input.month];					-- start of range season; keep this?
					tCOinS_date.rftchron = season[input.month] .. '–' .. season[input.month2];	-- season–season year range
				end
			end
		end
		tCOinS_date.rftdate = date;
		return;																	-- done
	end
	
	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
	['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
	}


--[[--------------------------< 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 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 ISO 8601 format date; see make_COInS_date()

]]

local function check_date (date_string, tCOinS_date, test_accessdate)
	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)) 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);

	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);

	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);

	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]);
		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
		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);										-- for metadata

	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) and 0 ~= get_season_number(month2) then	-- both must be or season year, not mixed
			month = get_season_number(month);
			month2 = get_season_number(month2);
		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)) 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);
		else
			month = get_season_number(month);
			month2 = get_season_number(month2);
		end
		year2=year;
		
	elseif mw.ustring.match(date_string, patterns['My'][1]) then				-- month/season year or 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
		if not is_valid_month_or_season (month) and 0 == is_proper_name (month) 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);
		elseif 0 ~= get_season_number(month) then
			month = get_season_number(month);
		else
			month = is_proper_name (month);										-- must be proper name; not supported in COinS
		end

	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

	elseif date_string:match (patterns['y'][1]) then							-- year; here accept either YYY or YYYY
		anchor_year, year=date_string:match (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 test_accessdate then														-- test accessdate 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; accessdate must not be a range
				if not is_valid_accessdate (year..'-'..month..'-'..day) then	
					return false;												-- return false when accessdate out of bounds
				end
		else
			return false;														-- return false when accessdate 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);

	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,
a single error message is created as the dates are tested.

]]

local function dates(date_parameters_list, tCOinS_date)
	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 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.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								-- if |date=n.d. with or without a CITEREF disambiguator
					good_date, anchor_year, COinS_date = true, v.val:match("((n%.d%.)%a?)");	--"n.d."; no error when date parameter is set to no date
				elseif v.val:match("^nd%a?$") then								-- if |date=nd with or without a CITEREF disambiguator
					good_date, anchor_year, COinS_date = true, v.val:match("((nd)%a?)");	--"nd";	no error when date parameter is set to no date
				else
					good_date, anchor_year, COinS_date = check_date (v.val, tCOinS_date);	-- go test the date
				end
			elseif 'year'==k then												-- if the parameter is |year= it should hold only a year value
				if v.val:match("^[1-9]%d%d%d?%a?$") 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 'access-date'==k then										-- if the parameter is |date=
				good_date = check_date (v.val, nil, true);						-- go test the date; nil is a placeholder; true is the test_accessdate flag
			elseif 'embargo'==k then											-- if the parameter is |embargo=
				good_date = check_date (v.val);									-- 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 |embargo= date a single dmy, mdy, or ymd formatted date? yes:returns embargo; no: returns 9999
				end
			else																-- any other date-holding parameter
				good_date = check_date (v.val);									-- 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 .. "&#124;" .. v.name .. "=";		-- add the failed parameter
			end
		end
	end
	return anchor_year, embargo_date, error_message;							-- 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 returns a 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)

]]

local function year_date_check (year_string, date_string)
	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
		result = 0;																-- no recognizable year in date
	end
	return result;
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 patern_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

--	if 'yMd' == format_param and in_array (pattern_idx, {'yMd', 'Md-dy', 'd-dMy', 'dM-dMy', 'Md-Mdy', 'dMy-dMy', 'Mdy-Mdy'}) then	-- not supported at en.wiki
	if 'yMd' == format_param then												-- not supported at en.wiki
		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 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_s'][tonumber(t.m)];					-- convert it to a month name
		else
			t.m = cfg.date_names['inv_local_l'][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
		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_s'][t[mon]]) or cfg.date_names['inv_local_l'][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 {{use xxx dates}} templates.  If found, xxx becomes the global date format as xxx-all.  If |cs1-dates= in
{{use xxx dates}} 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 {{use xxx dates}} 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 {{use xxx dates}}; 
		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 {{use xxx dates}}
		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
						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) then
			if not mw.ustring.match (param_val.val, '%d%d%d%d%-%d%d%-%d%d') 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
	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 month names to local-language month 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;
	
	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 dates in the date (single date or date range)
				if cfg.date_names.en.long[month] then
					mode = 'F';													-- English name is long so use long local name
				elseif cfg.date_names.en.short[month] then
					mode = 'M';													-- English name is short so use short local name
				else
					mode = nil;													-- not an English month name; could be local language month name or an English season name
				end
		
				if mode then													-- might be a season
					xlate = mw.getContentLanguage():formatDate(mode, '1' .. month);	-- translate the month name to this local language
					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)
	is_set = utilities_page_ptr.is_set;											-- import functions from selected Module:Citation/CS1/Utilities module
	in_array = utilities_page_ptr.in_array;										-- import functions from selected Module:Citation/CS1/Utilities module
	cfg = cfg_table_ptr;														-- import tables from selected Module:Citation/CS1/Configuration
end


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

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