# Module:ISOdate

---

This module is intended for processing of date strings.  

Please do not modify this code without applying the changes first at Module:ISOdate/sandbox and testing  
at Module:ISOdate/sandbox/testcases and Module talk:ISOdate/sandbox/testcases.  

Authors and maintainers:  
- User:Parent5446 - original version of the function mimicking template:ISOdate
- User:Jarekt - original version of the functions mimicking template:Date and template:ISOyear

local p = {}  

-- =======================================  
-- === Dependencies ======================  
-- =======================================  
local D = require('Module:DateI18n') -- the enwp version of c:Module:Date  

---
ISOyear  

This function returns year part of date string.  

Usage:  

Parameters  
1: The date string  

Error Handling:  
If the string does not look like it contain the year than the function will not return anything.  
That is the preferred treatment for the template:Creator which is the main (only?) template calling it.  

function p.ISOyear  
return p._ISOyear( .args[1] )  
end  

function p._ISOyear( input )  
if not input then  
return ''  
end  
input = mw.text.trim( input )  

-- if empty string then return it  
if input == "" then  
return input  
end  

-- if number then return it  
if tonumber( input ) then  
return mw.ustring.format( '%04i', input )  
end  

-- otherwise use regular expression match  
input = mw.ustring.match( input, '^+?(-?%d%d?%d?%d?)-' )  
if input and tonumber( input ) then  
return mw.ustring.format( '%04i', input )  
else  
return ''  
end  
end  

---
ISOdate  

This function is the core part of the ISOdate template.  

Usage:  

Parameters:  
1: The date string  
lang: The language to display it in  
form: Language format (genitive, etc.) for some languages  
class: CSS class for the <time> node  

Error Handling:  
If the string does not look like it contain the proper ISO date than the function will return the original string.  

That is the preferred treatment for the template:Information (and similar templates) which calling it.  

function p.ISOdate  
local datestr, succeded  
local args = .args  
if not (args.lang and mw.language.isSupportedLanguage(args.lang)) then  
args.lang = :callParserFunction( "int", "lang" ) -- get user's chosen language  
end  
datestr, succeded = p._ISOdate(  
mw.text.trim(args[1]),  
args.lang, -- language  
args.case or '', -- allows to specify grammatical case for the month for languages that use them  
args.class or 'dtstart', -- allows to set the html class of the time node where the date is included.  
args.trim_year or '100-999' -- by default pad one and 2 digit years to be 4 digit long, while keeping 3 digit years as is  
return datestr  
end  

function p._ISOdate(datestr, lang, case, class, trim_year)  

-- pattern: regexp - regular expresion to test; dlen - number of date elements; tail = which element is a "tail" if any  
-- regexp hints:  
-- 1) Strings starting with "^" and ending with "$" indicate whole string match  
-- 2) optional tail part copied as-is and following the main parsed part of the date have to be separated from the date by a whitespace, so "(\s.+)?"  
local patterns = {  
-- strings starting with YYYY-MM-DD HH:MM:SS. Year 4 digits (if we know seconds than it was within the last 100 years), the rest 1-2  
-- date and time can be separated by space or "T" and there could be a "Z" on the end indicating "Zulu" time zone  
{dlen=6, tail=7, regexp="^+?(%d%d%d%d)-(%d%d?)-(%d%d?)[ T](%d%d?):(%d%d?):(%d%d?)Z?(%s.*)"},  
{dlen=6, tail=0, regexp="^+?(%d%d%d%d)-(%d%d?)-(%d%d?)[ T](%d%d?):(%d%d?):(%d%d?)Z?$"},  
-- strings starting with YYYY-MM-DD HH:MM. Year 4 digits, the rest 1-2  
-- (if one knows hour and minute than it was probably after a year 1000)  
{dlen=5, tail=6, regexp="^+?(%d%d%d%d)-(%d%d?)-(%d%d?)[ T](%d%d?):(%d%d?)(%s.+)"},  
{dlen=5, tail=0, regexp="^+?(%d%d%d%d)-(%d%d?)-(%d%d?)[ T](%d%d?):(%d%d?)$"},  
-- strings starting with YYYY-MM-DD. Year 1-4 digits, the rest 1-2  
{dlen=3, tail=4, regexp="^+?(%d%d?%d?%d?)-(%d%d?)-(%d%d?)(%s.+)"},  
{dlen=3, tail=0, regexp="^+?(%d%d?%d?%d?)-(%d%d?)-(%d%d?)$"},  
-- strings starting with YYYY-MM. Year 3-4 digits, month 2 digits  
-- (want to avoit converting to dates strings like 10-5 = 5  
{dlen=2, tail=3, regexp="^+?(%d%d%d%d?)-(%d%d)(%s.+)"},  
-- if whole string is in YYYY-MM form: If Year 1-4 digits, month 1-2 digits  
{dlen=2, tail=0, regexp="^+?(%d%d?%d?%d?)-(%d%d?)$"},  
-- string starts with a number -> it has to be 3 or 4 digit long to be a year  
{dlen=1, tail=2, regexp="^+?(%d%d%d%d?)(%s.+)"},  
-- if whole string is a number (1-4 digit long) than it will be interpreted as a year  
{dlen=1, tail=0, regexp="^+?(%d%d?%d?%d?)$"},  
}  

-- create datevec based on which variables are provided  
local datevec, tail, formatNum  
datevec, tail, formatNum = p.test_date_formats(datestr or '', patterns)  
if datevec[1]=='' or datevec[1]==nil then  
-- quickly return if datestr does not look like date (it could be a template)  
return datestr, false  
end  

-- call p._Date function to format date string  
local succeded, datestr2  
succeded, datestr2 = pcall( D._Date, datevec, lang, case, class, trim_year)  
if succeded and datestr2~='' then  
return mw.text.trim( datestr2 .. tail), true  
else -- in case of errors return the original string  
return datestr, false  
end  
end  

function p.ISOdate_extended  
-- pattern: regexp - regular expresion to test; dlen - number of date elements; tail = which element is a "tail" if any  
-- regexp hints:  
-- 1) Strings starting with "^" and ending with "$" indicate whole string match  
-- 2) optional tail part copied as-is and following the main parsed part of the date have to be separated from the date by a whitespace, so "(\s.+)?"  

local datestr, succeded  
local args = .args  
if not (args.lang and mw.language.isSupportedLanguage(args.lang)) then  
args.lang = :callParserFunction( "int", "lang" ) -- get user's chosen language  
end  
datestr, succeded = p._ISOdate(  
mw.text.trim(args[1]),  
args.lang, -- language  
args.case or '', -- allows to specify grammatical case for the month for languages that use them  
args.class or 'dtstart', -- allows to set the html class of the time node where the date is included.  
args.trim_year or '100-999' -- by default pad one and 2 digit years to be 4 digit long, while keeping 3 digit years as is  
if succeded then  
return datestr  
end  

local patterns = {  
-- Exended set of recognized formats: like MM/DD/YYYY  
{dlen=3, tail=4, regexp="^(%d%d?)[-./](%d%d?)[-./](%d%d%d%d)(%s.+)"},  
{dlen=3, tail=0, regexp="^(%d%d?)[-./](%d%d?)[-./](%d%d%d%d)$"},  
{dlen=3, tail=0, regexp="^(%d%d?)%s(%w+)%s(%d%d%d%d)$"},  
{dlen=3, tail=0, regexp="^(%w+)%s(%d%d?),%s(%d%d%d%d)$"},  
}  

local datevec, tail, formatNum, category = ''  
datevec, tail, formatNum = p.test_date_formats(.args[1], patterns)  
if formatNum==1 or formatNum==2 then  
vec = datevec;  
if tonumber(datevec[1])>12 then  
.args[1] = string.format('%04i-%02i-%02i', datevec[3], datevec[2], datevec[1] )  
category = ''  
return mw.text.trim( p.ISOdate .. tail);  
elseif tonumber(datevec[2])>12 then  
.args[1] = string.format('%04i-%02i-%02i', datevec[3], datevec[1], datevec[2] )  
category = ''  
return mw.text.trim( p.ISOdate .. tail);  
end  
elseif (formatNum==3 or formatNum==4) and (datevec[3]=='' or datevec[3]~=nil) then  
local str = mw.getCurrentFrame:callParserFunction( "#time", { 'Y-m-d', datestr} )  
local vec = {str:match( "^(%d%d?%d?%d?)-(%d%d?)-(%d%d?)$" )}  
if vec and vec[1]~=nil then  
.args[1] = string.format('%04i-%02i-%02i', vec[1], vec[2], vec[3] )  
category = ''  
return p.ISOdate;  
end  
end  
return datestr  
end  

function p.test_date_formats(datestr, patterns)  
-- pattern: regexp - regular expresion to test; dlen - number of date elements; tail = which element is a "tail" if any  

local datevec = {*,*,*,*,*,*}  
local tail = ''  
local vec, pat  
local formatNum = 0  
for i, pat in ipairs( patterns ) do  
vec = {datestr:match( pat.regexp )}  
if vec and vec[1]~=nil then  
for j=1,pat.dlen do  
datevec[j] = vec[j]  
end  
if pat.tail>0 and vec[pat.tail]~=nil then  
tail = mw.ustring.gsub(' ' .. vec[pat.tail], ' +', ' ')  
end  
formatNum = i  
break  
end  
end  
return datevec, tail, formatNum  
end  

return p