Module:Citation/Identifiers

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

local is_set, in_array, set_error, select_one, add_maint_cat, substitute, make_wikilink;	-- functions in Module:Citation/Utilities

local z;																		-- table of tables defined in Module:Citation/Utilities

local cfg;																		-- table of configuration tables that are defined in Module:Citation/Configuration

--============================<< H E L P E R  F U N C T I O N S >>============================================

--[[--< E X T E R N A L _ L I N K _ I D >--

Formats a wiki style external link

]]

local function external_link_id(options) local url_string = options.id; local ext_link; local this_wiki_code = cfg.this_wiki_code;									-- wikipedia subdomain; 'en' for en.wikipedia.org local wd_article;															-- article title from wikidata if options.encode == true or options.encode == nil then url_string = mw.uri.encode( url_string ); end

ext_link = mw.ustring.format ('[%s%s%s %s]', options.prefix, url_string, options.suffix or "", mw.text.nowiki(options.id)); if is_set(options.access) then ext_link = substitute (cfg.presentation['ext-link-access-signal'], {cfg.presentation[options.access].class, cfg.presentation[options.access].title, ext_link});	-- add the free-to-read / paywall lock end

--	this_wiki_code = mw.language.getContentLanguage:getCode;				-- get this wikipedia's language code (subdomain) if string.match (mw.site.server, 'wikidata') then this_wiki_code = mw.getCurrentFrame:preprocess('');		-- on wikidata so use interface language setting instead end if is_set (options.q) and mw.wikibase then									-- wikibase test here avoids script errors in third party wikis that aren't using mw.wikibase extension wd_article = mw.wikibase.getEntity (options.q):getSitelink (this_wiki_code .. 'wiki');	-- fetch article title from wd		if wd_article then wd_article = table.concat ({':', this_wiki_code, ':', wd_article});	-- make interwiki link if taken from wd; leading colon required end end

return table.concat	({		make_wikilink (wd_article or options.link, options.label),				-- wikidata link or locally specified		options.separator or ' ',		ext_link		}); end

--[[--< I N T E R N A L _ L I N K _ I D >--

Formats a wiki style internal link

]]

local function internal_link_id(options) local id = mw.ustring.gsub (options.id, '%d', cfg.date_names.local_digits);	-- translate 'local' digits to Western 0-9

return table.concat (		{		make_wikilink (options.link, options.label),		options.separator or ' ',		make_wikilink ( table.concat (				{				options.prefix,				id,																-- translated to western digits				options.suffix or ''				}), substitute (cfg.presentation['bdi'], {'', mw.text.nowiki (options.id)})	-- bdi tags to prevent Latn script identifiers from being reversed at rtl language wikis );																	-- nowiki because MediaWiki still has magic links for ISBN and the like; TODO: is it really required?		}); end

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

Determines if a PMC identifier's online version is embargoed. Compares the date in |embargo= against today's date. If embargo date is in the future, returns the content of |embargo=; otherwise, returns and empty string because the embargo has expired or because
 * embargo= was not set in this cite.

]]

local function is_embargoed (embargo) if is_set (embargo) then local lang = mw.getContentLanguage; local good1, embargo_date, good2, todays_date; good1, embargo_date = pcall( lang.formatDate, lang, 'U', embargo ); good2, todays_date = pcall( lang.formatDate, lang, 'U' ); if good1 and good2 then													-- if embargo date and today's date are good dates if tonumber( embargo_date ) >= tonumber( todays_date ) then			-- is embargo date is in the future? return embargo;													-- still embargoed else add_maint_cat ('embargo') return '';														-- unset because embargo has expired end end end return '';																	-- |embargo= not set return empty string end

--[[--< IS _ V A L I D _ I S X N >-

ISBN-10 and ISSN validator code calculates checksum across all isbn/issn digits including the check digit. ISBN-13 is checked in isbn.

If the number is valid the result will be 0. Before calling this function, issbn/issn must be checked for length and stripped of dashes, spaces and other non-isxn characters.

]]

local function is_valid_isxn (isxn_str, len) local temp = 0; isxn_str = { isxn_str:byte(1, len) };	-- make a table of byte values '0' → 0x30 .. '9' → 0x39, 'X' → 0x58 len = len+1;							-- adjust to be a loop counter for i, v in ipairs( isxn_str ) do		-- loop through all of the bytes and calculate the checksum if v == string.byte( "X" ) then		-- if checkdigit is X (compares the byte value of 'X' which is 0x58) temp = temp + 10*( len - i );	-- it represents 10 decimal else temp = temp + tonumber( string.char(v) )*(len-i); end end return temp % 11 == 0;					-- returns true if calculation result is zero end

--[[--< IS _ V A L I D _ I S X N _ 1 3 >---

ISBN-13 and ISMN validator code calculates checksum across all 13 isbn/ismn digits including the check digit. If the number is valid, the result will be 0. Before calling this function, isbn-13/ismn must be checked for length and stripped of dashes, spaces and other non-isxn-13 characters.

]]

local function is_valid_isxn_13 (isxn_str) local temp=0; isxn_str = { isxn_str:byte(1, 13) };										-- make a table of byte values '0' → 0x30 .. '9' → 0x39 for i, v in ipairs( isxn_str ) do		temp = temp + (3 - 2*(i % 2)) * tonumber( string.char(v) );				-- multiply odd index digits by 1, even index digits by 3 and sum; includes check digit end return temp % 10 == 0;														-- sum modulo 10 is zero when isbn-13/ismn is correct end

--[[--< N O R M A L I Z E _ L C C N >--

lccn normalization (http://www.loc.gov/marc/lccn-namespace.html#normalization) 1. Remove all blanks. 2. If there is a forward slash (/) in the string, remove it, and remove all characters to the right of the forward slash. 3. If there is a hyphen in the string: a. Remove it. b. Inspect the substring following (to the right of) the (removed) hyphen. Then (and assuming that steps 1 and 2 have been carried out): 1. All these characters should be digits, and there should be six or less. (not done in this function) 2. If the length of the substring is less than 6, left-fill the substring with zeroes until the length is six.

Returns a normalized lccn for lccn to validate. There is no error checking (step 3.b.1) performed in this function. ]]

local function normalize_lccn (lccn) lccn = lccn:gsub ("%s", "");									-- 1. strip whitespace

if nil ~= string.find (lccn,'/') then lccn = lccn:match ("(.-)/");								-- 2. remove forward slash and all character to the right of it	end

local prefix local suffix prefix, suffix = lccn:match ("(.+)%-(.+)");						-- 3.a remove hyphen by splitting the string into prefix and suffix

if nil ~= suffix then											-- if there was a hyphen suffix=string.rep("0", 6-string.len (suffix)) .. suffix;	-- 3.b.2 left fill the suffix with 0s if suffix length less than 6 lccn=prefix..suffix;										-- reassemble the lccn end return lccn; end

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

--[[--< A R X I V >

See: http://arxiv.org/help/arxiv_identifier

format and error check arXiv identifier. There are three valid forms of the identifier: the first form, valid only between date codes 9108 and 0703 is: arXiv:. /  where: is a string of alpha characters - may be hyphenated; no other punctuation is a string of alpha characters - may be hyphenated; no other punctuation; not the same as |class= parameter which is not supported in this form is four digits in the form YYMM where YY is the last two digits of the four-digit year and MM is the month number January = 01 first digit of YY for this form can only 9 and 0 is a three-digit number is a 1 or more digit number preceded with a lowercase v; no spaces (undocumented) the second form, valid from April 2007 through December 2014 is: arXiv:. where: is four digits in the form YYMM where YY is the last two digits of the four-digit year and MM is the month number January = 01 is a four-digit number is a 1 or more digit number preceded with a lowercase v; no spaces

the third form, valid from January 2015 is: arXiv:. where: and are as defined for 0704-1412 is a five-digit number ]]

local function arxiv (id, class) local handler = cfg.id_handlers['ARXIV']; local year, month, version; local err_cat = false;														-- assume no error message local text;																	-- output text if id:match("^%a[%a%.%-]+/[90]%d[01]%d%d%d%d$") or id:match("^%a[%a%.%-]+/[90]%d[01]%d%d%d%dv%d+$") then	-- test for the 9108-0703 format w/ & w/o version year, month = id:match("^%a[%a%.%-]+/([90]%d)([01]%d)%d%d%d[v%d]*$"); year = tonumber(year); month = tonumber(month); if ((not (90 year)) or (1 > month or 12 < month)) or		-- if invalid year or invalid month ((91 == year and 7 > month) or (7 == year and 3 < month)) then		-- if years ok, are starting and ending months ok? err_cat = true;													-- flag for error message end

elseif id:match("^%d%d[01]%d%.%d%d%d%d$") or id:match("^%d%d[01]%d%.%d%d%d%dv%d+$") then	-- test for the 0704-1412 w/ & w/o version year, month = id:match("^(%d%d)([01]%d)%.%d%d%d%d[v%d]*$"); year = tonumber(year); month = tonumber(month); if ((7 > year) or (14 < year) or (1 > month or 12 < month)) or			-- is year invalid or is month invalid? (doesn't test for future years) ((7 == year) and (4 > month)) then --or									-- when year is 07, is month invalid (before April)? err_cat = true;													-- flag for error message end

elseif id:match("^%d%d[01]%d%.%d%d%d%d%d$") or id:match("^%d%d[01]%d%.%d%d%d%d%dv%d+$") then	-- test for the 1501- format w/ & w/o version year, month = id:match("^(%d%d)([01]%d)%.%d%d%d%d%d[v%d]*$"); year = tonumber(year); month = tonumber(month); if ((15 > year) or (1 > month or 12 < month)) then						-- is year invalid or is month invalid? (doesn't test for future years) err_cat = true;													-- flag for error message end

else err_cat = true;															-- not a recognized format; flag for error message end

err_cat = err_cat and table.concat ({' ', set_error ('bad_arxiv')}) or '';	-- set error message if flag is true text = external_link_id({link = handler.link, label = handler.label, q = handler.q,			prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode, access=handler.access}) .. err_cat;

if is_set (class) then if id:match ('^%d+') then text = table.concat ({text, ' //arxiv.org/archive/', class, ' ', class, ''});	-- external link within square brackets, not wikilink else text = table.concat ({text, ' ', set_error ('class_ignored')}); end end

return text; end

--[[--< B I B C O D E >

Validates (sort of) and formats a bibcode id.

Format for bibcodes is specified here: http://adsabs.harvard.edu/abs_doc/help_pages/data.html#bibcodes

But, this: 2015arXiv151206696F is apparently valid so apparently, the only things that really matter are length, 19 characters and first four digits must be a year. This function makes these tests: length must be 19 characters characters in position 1–4 must be digits and must represent a year in the range of 1000 – next year 5 must be a letter 6–8 must be letter, digit, ampersand, or dot (ampersand cannot directly precede a dot; &. ) 9–18 must be letter, digit, or dot 19 must be a letter or dot

]]

local function bibcode (id, access) local handler = cfg.id_handlers['BIBCODE']; local err_type; local year;

local text = external_link_id({link=handler.link, label=handler.label, q = handler.q,		prefix=handler.prefix, id=id, separator=handler.separator, encode=handler.encode,		access=access}); if 19 ~= id:len then err_type = 'length'; else year = id:match ("^(%d%d%d%d)[%a][%w&%.][%w&%.][%w&%.][%w.]+[%a%.]$")	-- if not year then														-- if nil then no pattern match err_type = 'value';													-- so value error else local next_year = tonumber(os.date ('%Y'))+1;						-- get the current year as a number and add one for next year year = tonumber (year);												-- convert year portion of bibcode to a number if (1000 > year) or (year > next_year) then err_type = 'year';												-- year out of bounds end if id:find('&%.') then err_type = 'journal';											-- journal abbreviation must not have '&.' (if it does its missing a letter) end end end

if is_set (err_type) then													-- if there was an error detected text = text .. ' ' .. set_error( 'bad_bibcode', {err_type}); end return text; end

--[[--< B I O R X I V >-

Format bioRxiv id and do simple error checking. BiorXiv ids are exactly 6 digits. The bioRxiv id is the number following the last slash in the bioRxiv-issued DOI: https://doi.org/10.1101/078733 -> 078733

]]

local function biorxiv(id) local handler = cfg.id_handlers['BIORXIV']; local err_cat = '';															-- presume that bioRxiv id is valid if nil == id:match("^%d%d%d%d%d%d$") then									-- if bioRxiv id has anything but six digits err_cat = ' ' .. set_error( 'bad_biorxiv');	-- set an error message end return external_link_id({link = handler.link, label = handler.label, q = handler.q,			prefix=handler.prefix,id=id,separator=handler.separator,			encode=handler.encode, access=handler.access}) .. err_cat; end

--[[--< C I T E S E E R X >

CiteSeerX use their own notion of "doi" (not to be confused with the identifiers resolved via doi.org).

The description of the structure of this identifier can be found at Help_talk:Citation_Style_1/Archive_26#CiteSeerX_id_structure ]]

local function citeseerx (id) local handler = cfg.id_handlers['CITESEERX']; local matched; local text = external_link_id({link=handler.link, label=handler.label, q = handler.q,		prefix=handler.prefix, id=id, separator=handler.separator, encode=handler.encode,		access=handler.access}); matched = id:match ("^10%.1%.1%.[1-9]%d?%d?%d?%.[1-9]%d?%d?%d?$"); if not matched then text = text .. ' ' .. set_error( 'bad_citeseerx' ); end return text; end

--[[--< D O I >

Formats a DOI and checks for DOI errors.

DOI names contain two parts: prefix and suffix separated by a forward slash. Prefix: directory indicator '10.' followed by a registrant code Suffix: character string of any length chosen by the registrant

This function checks a DOI name for: prefix/suffix. If the doi name contains spaces or endashes, or, if it ends with a period or a comma, this function will emit a bad_doi error message.

DOI names are case-insensitive and can incorporate any printable Unicode characters so the test for spaces, endash, and terminal punctuation may not be technically correct but it appears, that in practice these characters are rarely if ever used in doi names.

]]

local function doi(id, inactive, access) local cat = "" local handler = cfg.id_handlers['DOI']; local text; if is_set(inactive) then local inactive_year = inactive:match("%d%d%d%d") or '';					-- try to get the year portion from the inactive date local inactive_month, good;

if is_set (inactive_year) then if 4 < inactive:len then											-- inactive date has more than just a year (could be anything) local lang_obj = mw.getContentLanguage;						-- get a language object for this wiki good, inactive_month = pcall (lang_obj.formatDate, lang_obj, 'F', inactive);	-- try to get the month name from the inactive date if not good then inactive_month = nil;										-- something went wrong so make sure this is unset end end else inactive_year = nil;												-- |doi-broken= has something but it isn't a date end if is_set(inactive_year) and is_set (inactive_month) then table.insert( z.error_categories, 'Pages with DOIs inactive as of ' .. inactive_year .. ' ' .. inactive_month);	-- use inactive month in category name elseif is_set(inactive_year) then table.insert( z.error_categories, 'Pages with DOIs inactive as of ' .. inactive_year); else table.insert( z.error_categories, 'Pages with inactive DOIs');		-- when inactive doesn't contain a recognizable date end inactive = " (" .. cfg.messages['inactive'] .. ' ' .. inactive .. ')'; end

text = external_link_id({link = handler.link, label = handler.label, q = handler.q,		prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode, access=access}) .. (inactive or '')

local registrant = id:match ('^10%.([^/]+)/[^%s–]-[^%.,]$');				-- registrant set when doi has the proper basic form registrant_err_patterns = {													-- these patterns are for code ranges that are not supported '^[^1-3]%d%d%d%d%.%d%d*$',												-- 5 digits with subcode (0xxxx, 40000+); accecpts: 10000–39999 '^[^1-3]%d%d%d%d$',														-- 5 digits without subcode (0xxxx, 40000+); accecpts: 10000–39999 '^[^1-9]%d%d%d%.%d%d*$',												-- 4 digits with subcode (0xxx); accecpts: 1000–9999 '^[^1-9]%d%d%d$',														-- 4 digits without subcode (0xxx); accecpts: 1000–9999 '^%d%d%d%d%d%d+',														-- 6 or more digits '^%d%d?%d?$',															-- less than 4 digits without subcode (with subcode is legitimate) '^5555$',																-- test registrant will never resolve }	if registrant then															-- when doi has proper form for i, pattern in ipairs (registrant_err_patterns) do					-- spin through error patterns if registrant:match (pattern) then									-- to validate registrant codes cat = ' ' .. set_error ('bad_doi');								-- when found, mark this doi as bad break;															-- and done end end else cat = ' ' .. set_error ('bad_doi');										-- invalid directory or malformed end

return text .. cat end

--[[--< H D L >

Formats an HDL with minor error checking.

HDL names contain two parts: prefix and suffix separated by a forward slash. Prefix: character string using any character in the UCS-2 character set except '/' Suffix: character string of any length using any character in the UCS-2 character set chosen by the registrant

This function checks a HDL name for: prefix/suffix. If the HDL name contains spaces, endashes, or, if it ends with a period or a comma, this function will emit a bad_hdl error message.

HDL names are case-insensitive and can incorporate any printable Unicode characters so the test for endashes and terminal punctuation may not be technically correct but it appears, that in practice these characters are rarely if ever used in HDLs.

]]

local function hdl(id, access) local handler = cfg.id_handlers['HDL']; local text = external_link_id({link = handler.link, label = handler.label, q = handler.q,			prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode, access=access})

if nil == id:match("^[^%s–]-/[^%s–]-[^%.,]$") then							-- hdl must contain a fwd slash, must not contain spaces, endashes, and must not end with period or comma text = text .. ' ' .. set_error( 'bad_hdl' ); end return text; end

--[[--< I S B N >--

Determines whether an ISBN string is valid

]]

local function isbn( isbn_str ) if nil ~= isbn_str:match("[^%s-0-9X]") then return false, 'invalid character';										-- fail if isbn_str contains anything but digits, hyphens, or the uppercase X	end isbn_str = isbn_str:gsub( "-", "" ):gsub( " ", "" );						-- remove hyphens and spaces local len = isbn_str:len; if len ~= 10 and len ~= 13 then return false, 'length';													-- fail if incorrect length end

if len == 10 then if isbn_str:match( "^%d*X?$" ) == nil then								-- fail if isbn_str has 'X' anywhere but last position return false, 'invalid form'; end return is_valid_isxn(isbn_str, 10), 'checksum'; else if isbn_str:match( "^%d+$" ) == nil then return false, 'invalid character';									-- fail if isbn13 is not all digits end if isbn_str:match( "^97[89]%d*$" ) == nil then return false, 'invalid prefix';										-- fail when isbn13 does not begin with 978 or 979 end if isbn_str:match ('^9790') then return false, 'invalid group id';									-- group identifier '0' is reserved to ismn end return is_valid_isxn_13 (isbn_str), 'checksum'; end end

--[[--< A M A Z O N >--

Formats a link to Amazon. Do simple error checking: asin must be mix of 10 numeric or uppercase alpha characters. If a mix, first character must be uppercase alpha; if all numeric, asins must be 10-digit isbn. If 10-digit isbn, add a maintenance category so a bot or awb script can replace |asin= with |isbn=. Error message if not 10 characters, if not isbn10, if mixed and first character is a digit.

This function is positioned here because it calls isbn

]]

local function asin(id, domain) local err_cat = ""

if not id:match("^[%d%u][%d%u][%d%u][%d%u][%d%u][%d%u][%d%u][%d%u][%d%u][%d%u]$") then err_cat = ' ' .. set_error ('bad_asin');								-- asin is not a mix of 10 uppercase alpha and numeric characters else if id:match("^%d%d%d%d%d%d%d%d%d[%dX]$") then							-- if 10-digit numeric (or 9 digits with terminal X)			if isbn( id ) then													-- see if asin value is isbn10 add_maint_cat ('ASIN'); elseif not is_set (err_cat) then err_cat = ' ' .. set_error ('bad_asin');						-- asin is not isbn10 end elseif not id:match("^%u[%d%u]+$") then err_cat = ' ' .. set_error ('bad_asin');							-- asin doesn't begin with uppercase alpha end end if not is_set(domain) then domain = "com"; elseif in_array (domain, {'jp', 'uk'}) then			-- Japan, United Kingdom domain = "co." .. domain; elseif in_array (domain, {'au', 'br', 'mx'}) then	-- Australia, Brazil, Mexico domain = "com." .. domain; end local handler = cfg.id_handlers['ASIN']; return external_link_id({link=handler.link,		label=handler.label, q = handler.q, prefix=handler.prefix .. domain .. "/dp/",		id=id, encode=handler.encode, separator = handler.separator}) .. err_cat; end

--[[--< I S M N >--

Determines whether an ISMN string is valid. Similar to isbn-13, ismn is 13 digits begining 979-0-... and uses the same check digit calculations. See http://www.ismn-international.org/download/Web_ISMN_Users_Manual_2008-6.pdf section 2, pages 9–12.

]]

local function ismn (id) local handler = cfg.id_handlers['ISMN']; local text; local valid_ismn = true; local id_copy;

id_copy = id;																-- save a copy because this testing is destructive id=id:gsub( "[%s-–]", "" );													-- strip spaces, hyphens, and endashes from the ismn

if 13 ~= id:len or id:match( "^9790%d*$" ) == nil then					-- ismn must be 13 digits and begin 9790 valid_ismn = false; else valid_ismn=is_valid_isxn_13 (id);										-- validate ismn end

--	text = internal_link_id({link = handler.link, label = handler.label,		-- use this (or external version) when there is some place to link to --		prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode}) text = table.concat (		{		make_wikilink (handler.link, handler.label),		handler.separator,		id_copy		});		-- because no place to link to yet

if false == valid_ismn then text = text .. ' ' .. set_error( 'bad_ismn' )							-- add an error message if the ismn is invalid end return text; end

--[[--< I S S N >--

Validate and format an issn. This code fixes the case where an editor has included an ISSN in the citation but has separated the two groups of four digits with a space. When that condition occurred, the resulting link looked like this:

|issn=0819 4327 gives: 4327 0819 4327	-- can't have spaces in an external link This code now prevents that by inserting a hyphen at the issn midpoint. It also validates the issn for length and makes sure that the checkdigit agrees with the calculated value. Incorrect length (8 digits), characters other than 0-9 and X, or checkdigit / calculated value mismatch will all cause a check issn error message. The issn is always displayed with a hyphen, even if the issn was given as a single group of 8 digits.

]]

local function issn(id, e)	local issn_copy = id;														-- save a copy of unadulterated issn; use this version for display if issn does not validate local handler; local text; local valid_issn = true; if e then handler = cfg.id_handlers['EISSN']; else handler = cfg.id_handlers['ISSN']; end

id=id:gsub( "[%s-–]", "" );													-- strip spaces, hyphens, and endashes from the issn

if 8 ~= id:len or nil == id:match( "^%d*X?$" ) then						-- validate the issn: 8 digits long, containing only 0-9 or X in the last position valid_issn=false;														-- wrong length or improper character else valid_issn=is_valid_isxn(id, 8);										-- validate issn end

if true == valid_issn then id = string.sub( id, 1, 4 ) .. "-" .. string.sub( id, 5 );				-- if valid, display correctly formatted version else id = issn_copy;															-- if not valid, use the show the invalid issn with error message end text = external_link_id({link = handler.link, label = handler.label, q = handler.q,		prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode}) if false == valid_issn then text = text .. ' ' .. set_error( 'bad_issn', e and 'e' or '' )			-- add an error message if the issn is invalid end return text end

--[[--< J F M >---

A numerical identifier in the form nn.nnnn.nn

]]

local function jfm (id) local handler = cfg.id_handlers['JFM']; local id_num; local err_cat = ''; id_num = id:match ('^[Jj][Ff][Mm](.*)$');									-- identifier with jfm prefix; extract identifier

if is_set (id_num) then add_maint_cat ('jfm_format'); else																		-- plain number without mr prefix id_num = id;															-- if here id does not have prefix end

if id_num and id_num:match('^%d%d%.%d%d%d%d%.%d%d$') then id = id_num;															-- jfm matches pattern else err_cat = ' ' .. set_error( 'bad_jfm' );								-- set an error message end return external_link_id({link = handler.link, label = handler.label, q = handler.q,			prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode}) .. err_cat; end

--[[--< L C C N >--

Format LCCN link and do simple error checking. LCCN is a character string 8-12 characters long. The length of the LCCN dictates the character type of the first 1-3 characters; the rightmost eight are always digits. http://info-uri.info/registry/OAIHandler?verb=GetRecord&metadataPrefix=reg&identifier=info:lccn/

length = 8 then all digits length = 9 then lccn[1] is lower case alpha length = 10 then lccn[1] and lccn[2] are both lower case alpha or both digits length = 11 then lccn[1] is lower case alpha, lccn[2] and lccn[3] are both lower case alpha or both digits length = 12 then lccn[1] and lccn[2] are both lower case alpha

]]

local function lccn(lccn) local handler = cfg.id_handlers['LCCN']; local err_cat = '';															-- presume that LCCN is valid local id = lccn;															-- local copy of the lccn

id = normalize_lccn (id);													-- get canonical form (no whitespace, hyphens, forward slashes) local len = id:len;														-- get the length of the lccn

if 8 == len then if id:match("[^%d]") then												-- if LCCN has anything but digits (nil if only digits) err_cat = ' ' .. set_error( 'bad_lccn' );							-- set an error message end elseif 9 == len then														-- LCCN should be adddddddd if nil == id:match("%l%d%d%d%d%d%d%d%d") then							-- does it match our pattern? err_cat = ' ' .. set_error( 'bad_lccn' );							-- set an error message end elseif 10 == len then														-- LCCN should be aadddddddd or dddddddddd if id:match("[^%d]") then												-- if LCCN has anything but digits (nil if only digits) ... if nil == id:match("^%l%l%d%d%d%d%d%d%d%d") then					-- ... see if it matches our pattern err_cat = ' ' .. set_error( 'bad_lccn' );						-- no match, set an error message end end elseif 11 == len then														-- LCCN should be aaadddddddd or adddddddddd if not (id:match("^%l%l%l%d%d%d%d%d%d%d%d") or id:match("^%l%d%d%d%d%d%d%d%d%d%d")) then	-- see if it matches one of our patterns err_cat = ' ' .. set_error( 'bad_lccn' );							-- no match, set an error message end elseif 12 == len then														-- LCCN should be aadddddddddd if not id:match("^%l%l%d%d%d%d%d%d%d%d%d%d") then						-- see if it matches our pattern err_cat = ' ' .. set_error( 'bad_lccn' );							-- no match, set an error message end else err_cat = ' ' .. set_error( 'bad_lccn' );								-- wrong length, set an error message end

if not is_set (err_cat) and nil ~= lccn:find ('%s') then err_cat = ' ' .. set_error( 'bad_lccn' );								-- lccn contains a space, set an error message end

return external_link_id({link = handler.link, label = handler.label, q = handler.q,			prefix=handler.prefix,id=lccn,separator=handler.separator, encode=handler.encode}) .. err_cat; end

--[[--< M R >--

A seven digit number; if not seven digits, zero-fill leading digits to make seven digits.

]]

local function mr (id) local handler = cfg.id_handlers['MR']; local id_num; local id_len; local err_cat = ''; id_num = id:match ('^[Mm][Rr](%d+)$');										-- identifier with mr prefix

if is_set (id_num) then add_maint_cat ('mr_format'); else																		-- plain number without mr prefix id_num = id:match ('^%d+$');											-- if here id is all digits end

id_len = id_num and id_num:len or 0; if (7 >= id_len) and (0 ~= id_len) then id = string.rep ('0', 7-id_len ) .. id_num;								-- zero-fill leading digits else err_cat = ' ' .. set_error( 'bad_mr' );									-- set an error message end return external_link_id({link = handler.link, label = handler.label, q = handler.q,			prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode}) .. err_cat; end

--[[--< O C L C >--

Validate and format an oclc id. https://www.oclc.org/batchload/controlnumber.en.html archived at: https://web.archive.org/web/20161228233804/https://www.oclc.org/batchload/controlnumber.en.html

]]

local function oclc (id) local handler = cfg.id_handlers['OCLC']; local number; local err_msg = '';															-- empty string for concatenation if id:match('^ocm%d%d%d%d%d%d%d%d$') then									-- ocm prefix and 8 digits; 001 field (12 characters) number = id:match('ocm(%d+)');											-- get the number elseif id:match('^ocn%d%d%d%d%d%d%d%d%d$') then								-- ocn prefix and 9 digits; 001 field (12 characters) number = id:match('ocn(%d+)');											-- get the number elseif id:match('^on%d%d%d%d%d%d%d%d%d%d+$') then							-- on prefix and 10 or more digits; 001 field (12 characters) number = id:match('^on(%d%d%d%d%d%d%d%d%d%d+)$');						-- get the number elseif id:match('^%(OCoLC%)[1-9]%d*$') then									-- (OCoLC) prefix and variable number digits; no leading zeros; 035 field number = id:match('%(OCoLC%)([1-9]%d*)');								-- get the number if 9 < number:len then number = nil;														-- contrain to 1 to 9 digits; change this when oclc issues 10-digit numbers end elseif id:match('^%d+$') then												-- no prefix number = id;															-- get the number if 10 < number:len then number = nil;														-- contrain to 1 to 10 digits; change this when oclc issues 11-digit numbers end end

if number then																-- proper format id = number;															-- exclude prefix, if any, from external link else err_msg = ' ' .. set_error( 'bad_oclc' )								-- add an error message if the id is malformed end local text = external_link_id({link=handler.link, label=handler.label, q = handler.q,		prefix=handler.prefix, id=id, separator=handler.separator, encode=handler.encode}) .. err_msg;

return text; end

--[[--< O P E N L I B R A R Y >

Formats an OpenLibrary link, and checks for associated errors.

]]

local function openlibrary(id, access) local code; local handler = cfg.id_handlers['OL']; local ident; ident, code = id:gsub('^OL', ''):match("^(%d+([AMW]))$");					-- optional OL prefix followed immediately by digits followed by 'A', 'M', or 'W'; remove OL prefix

if not is_set (ident) then													-- if malformed return an error return external_link_id({link=handler.link, label=handler.label, q = handler.q,			prefix=handler.prefix .. 'OL',			id=id, separator=handler.separator,	encode = handler.encode,			access = access}) .. ' ' .. set_error( 'bad_ol' ); end id = ident;																	-- use ident without the optional OL prefix (it has been removed) if ( code == "A" ) then return external_link_id({link=handler.link, label=handler.label, q = handler.q,			prefix=handler.prefix .. 'authors/OL',			id=id, separator=handler.separator,	encode = handler.encode,			access = access}) end if ( code == "M" ) then return external_link_id({link=handler.link, label=handler.label, q = handler.q,			prefix=handler.prefix .. 'books/OL',			id=id, separator=handler.separator,	encode = handler.encode,			access = access}) end

if ( code == "W" ) then return external_link_id({link=handler.link, label=handler.label, q = handler.q,			prefix=handler.prefix .. 'works/OL',			id=id, separator=handler.separator,	encode = handler.encode,			access = access}) end end

--[[--< P M C >

Format a PMC, do simple error checking, and check for embargoed articles.

The embargo parameter takes a date for a value. If the embargo date is in the future the PMC identifier will not be linked to the article. If the embargo date is today or in the past, or if it is empty or omitted, then the PMC identifier is linked to the article through the link at cfg.id_handlers['PMC'].prefix.

PMC embargo date testing is done in function is_embargoed which is called earlier because when the citation has |pmc= but does not have a |url= then |title= is linked with the PMC link. Function is_embargoed returns the embargo date if the PMC article is still embargoed, otherwise it returns an empty string.

PMCs are sequential numbers beginning at 1 and counting up. This code checks the PMC to see that it contains only digits and is less than test_limit; the value in local variable test_limit will need to be updated periodically as more PMCs are issued.

]]

local function pmc(id, embargo) local test_limit = 7000000;													-- update this value as PMCs approach local handler = cfg.id_handlers['PMC']; local err_cat = '';															-- presume that PMC is valid local id_num; local text; id_num = id:match ('^[Pp][Mm][Cc](%d+)$');									-- identifier with pmc prefix

if is_set (id_num) then add_maint_cat ('pmc_format'); else																		-- plain number without pmc prefix id_num = id:match ('^%d+$');											-- if here id is all digits end

if is_set (id_num) then														-- id_num has a value so test it		id_num = tonumber(id_num);												-- convert id_num to a number for range testing if 1 > id_num or test_limit < id_num then								-- if PMC is outside test limit boundaries err_cat = ' ' .. set_error( 'bad_pmc' );							-- set an error message else id = tostring (id_num);												-- make sure id is a string end else																		-- when id format incorrect err_cat = ' ' .. set_error( 'bad_pmc' );								-- set an error message end if is_set (embargo) then													-- is PMC is still embargoed? text = table.concat (													-- still embargoed so no external link			{			make_wikilink (handler.link, handler.label),			handler.separator,			id,			err_cat			}); else text = external_link_id({link = handler.link, label = handler.label, q = handler.q,	-- no embargo date or embargo has expired, ok to link to article			prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode, access=handler.access}) .. err_cat; end return text; end

--[[--< P M I D >--

Format PMID and do simple error checking. PMIDs are sequential numbers beginning at 1 and counting up. This code checks the PMID to see that it contains only digits and is less than test_limit; the value in local variable test_limit will need to be updated periodically as more PMIDs are issued.

]]

local function pmid(id) local test_limit = 33000000;												-- update this value as PMIDs approach local handler = cfg.id_handlers['PMID']; local err_cat = '';															-- presume that PMID is valid if id:match("[^%d]") then													-- if PMID has anything but digits err_cat = ' ' .. set_error( 'bad_pmid' );								-- set an error message else																		-- PMID is only digits local id_num = tonumber(id);											-- convert id to a number for range testing if 1 > id_num or test_limit < id_num then								-- if PMID is outside test limit boundaries err_cat = ' ' .. set_error( 'bad_pmid' );							-- set an error message end end return external_link_id({link = handler.link, label = handler.label, q = handler.q,			prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode}) .. err_cat; end

--[[--< S S R N >--

Format an ssrn, do simple error checking

SSRNs are sequential numbers beginning at 100? and counting up. This code checks the ssrn to see that it is only digits and is greater than 99 and less than test_limit; the value in local variable test_limit will need to be updated periodically as more SSRNs are issued.

]]

local function ssrn (id) local test_limit = 3500000;													-- update this value as SSRNs approach local handler = cfg.id_handlers['SSRN']; local err_cat = '';															-- presume that SSRN is valid local id_num; local text; id_num = id:match ('^%d+$');												-- id must be all digits

if is_set (id_num) then														-- id_num has a value so test it		id_num = tonumber(id_num);												-- convert id_num to a number for range testing if 100 > id_num or test_limit < id_num then								-- if SSRN is outside test limit boundaries err_cat = ' ' .. set_error( 'bad_ssrn' );							-- set an error message end else																		-- when id format incorrect err_cat = ' ' .. set_error( 'bad_ssrn' );								-- set an error message end text = external_link_id({link = handler.link, label = handler.label, q = handler.q,		prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode, access=handler.access}) .. err_cat;

return text; end

--[[--< U S E N E T _ I D >

Validate and format a usenet message id. Simple error checking, looks for 'id-left@id-right' not enclosed in '<' and/or '>' angle brackets.

]]

local function usenet_id (id) local handler = cfg.id_handlers['USENETID'];

local text = external_link_id({link = handler.link, label = handler.label, q = handler.q,		prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode}) if not id:match('^.+@.+$') or not id:match('^[^<].*[^>]$')then				-- doesn't have '@' or has one or first or last character is '< or '>' text = text .. ' ' .. set_error( 'bad_usenet_id' )						-- add an error message if the message id is invalid end return text end

--[[--< Z B L >---

A numerical identifier in the form nnnn.nnnnn - leading zeros in the first quartet optional

format described here: http://emis.mi.sanu.ac.rs/ZMATH/zmath/en/help/search/

temporary format is apparently eight digits. Anything else is an error

]]

local function zbl (id) local handler = cfg.id_handlers['ZBL']; local err_cat = ''; if id:match('^%d%d%d%d%d%d%d%d$') then										-- is this identifier using temporary format? add_maint_cat ('zbl');													-- yes, add maint cat elseif not id:match('^%d?%d?%d?%d%.%d%d%d%d%d$') then						-- not temporary, is it normal format? err_cat = ' ' .. set_error( 'bad_zbl' );								-- no, set an error message end return external_link_id({link = handler.link, label = handler.label, q = handler.q,			prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode}) .. err_cat; end

--============================<< I N T E R F A C E  F U N C T I O N S >>==========================================

--[[--< B U I L D _ I D _ L I S T >

Takes a table of IDs created by extract_ids and turns it into a table of formatted ID outputs.

inputs: id_list – table of identifiers built by extract_ids options – table of various template parameter values used to modify some manually handled identifiers

]]

local function build_id_list( id_list, options ) local new_list, handler = {};

local function fallback(k) return { __index = function(t,i) return cfg.id_handlers[k][i] end } end; for k, v in pairs( id_list ) do												-- k is uc identifier name as index to cfg.id_handlers; e.g. cfg.id_handlers['ISBN'], v is a table -- fallback to read-only cfg handler = setmetatable( { ['id'] = v, ['access'] = options.IdAccessLevels[k] }, fallback(k) );

if handler.mode == 'external' then table.insert( new_list, {handler.label, external_link_id( handler ) } ); elseif handler.mode == 'internal' then table.insert( new_list, {handler.label, internal_link_id( handler ) } ); elseif handler.mode ~= 'manual' then error( cfg.messages['unknown_ID_mode'] ); elseif k == 'ARXIV' then table.insert( new_list, {handler.label, arxiv( v, options.Class ) } ); elseif k == 'ASIN' then table.insert( new_list, {handler.label, asin( v, options.ASINTLD ) } ); elseif k == 'BIBCODE' then table.insert( new_list, {handler.label, bibcode( v, handler.access ) } ); elseif k == 'BIORXIV' then table.insert( new_list, {handler.label, biorxiv( v ) } ); elseif k == 'CITESEERX' then table.insert( new_list, {handler.label, citeseerx( v ) } ); elseif k == 'DOI' then table.insert( new_list, {handler.label, doi( v, options.DoiBroken, handler.access ) } ); elseif k == 'EISSN' then table.insert( new_list, {handler.label, issn( v, true ) } );		-- true distinguishes eissn from issn elseif k == 'HDL' then table.insert( new_list, {handler.label, hdl( v, handler.access ) } ); elseif k == 'ISBN' then local ISBN = internal_link_id( handler ); local check; local err_type = ''; check, err_type = isbn( v ); if not check then if is_set(options.IgnoreISBN) then								-- ISBN is invalid; if |ignore-isbn-error= set add_maint_cat ('ignore_isbn_err');							-- ad a maint category else ISBN = ISBN .. set_error( 'bad_isbn', {err_type}, false, " ", "" );	-- else display an error message end elseif is_set(options.IgnoreISBN) then								-- ISBN is OK; if |ignore-isbn-error= set add_maint_cat ('ignore_isbn_err');								-- because |ignore-isbn-error= unnecessary end table.insert( new_list, {handler.label, ISBN } ); elseif k == 'ISMN' then table.insert( new_list, {handler.label, ismn( v ) } ); elseif k == 'ISSN' then table.insert( new_list, {handler.label, issn( v ) } ); elseif k == 'JFM' then table.insert( new_list, {handler.label, jfm( v ) } ); elseif k == 'LCCN' then table.insert( new_list, {handler.label, lccn( v ) } ); elseif k == 'MR' then table.insert( new_list, {handler.label, mr( v ) } ); elseif k == 'OCLC' then table.insert( new_list, {handler.label, oclc( v ) } ); elseif k == 'OL' or k == 'OLA' then table.insert( new_list, {handler.label, openlibrary( v, handler.access ) } ); elseif k == 'PMC' then table.insert( new_list, {handler.label, pmc( v, options.Embargo ) } ); elseif k == 'PMID' then table.insert( new_list, {handler.label, pmid( v ) } ); elseif k == 'SSRN' then table.insert( new_list, {handler.label, ssrn( v ) } ); elseif k == 'USENETID' then table.insert( new_list, {handler.label, usenet_id( v ) } ); elseif k == 'ZBL' then table.insert( new_list, {handler.label, zbl( v ) } ); else error( cfg.messages['unknown_manual_ID'] ); end end local function comp( a, b )	-- used in following table.sort return a[1]:lower < b[1]:lower; end table.sort( new_list, comp ); for k, v in ipairs( new_list ) do		new_list[k] = v[2]; end return new_list; end

--[[--< E X T R A C T _ I D S >

Populates ID table from arguments using configuration settings. Loops through cfg.id_handlers and searches args for any of the parameters listed in each cfg.id_handlers['...'].parameters. If found, adds the parameter and value to the identifier list. Emits redundant error message is more than one alias exists in args

]]

local function extract_ids( args ) local id_list = {};															-- list of identifiers found in args for k, v in pairs( cfg.id_handlers ) do										-- k is uc identifier name as index to cfg.id_handlers; e.g. cfg.id_handlers['ISBN'], v is a table v = select_one( args, v.parameters, 'redundant_parameters' );			-- v.parameters is a table of aliases for k; here we pick one from args if present if is_set(v) then id_list[k] = v; end									-- if found in args, add identifier to our list end return id_list; end

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

Fetches custom id access levels from arguments using configuration settings. Parameters which have a predefined access level (e.g. arxiv) do not use this function as they are directly rendered as free without using an additional parameter.

access-level values must match the case used in cfg.keywords_lists['id-access'] (lowercase unless there is some special reason for something else)

]]

local function extract_id_access_levels( args, id_list ) local id_accesses_list = {}; for k, v in pairs( cfg.id_handlers ) do		local access_param = v.custom_access;									-- name of identifier's access-level parameter if is_set(access_param) then local access_level = args[access_param];							-- get the assigned value if there is one if is_set (access_level) then if not in_array (access_level, cfg.keywords_lists['id-access']) then	-- exact match required table.insert( z.message_tail, { set_error( 'invalid_param_val', {access_param, access_level}, true ) } ); access_level = nil;											-- invalid so unset end if not is_set(id_list[k]) then									-- identifer access-level must have a matching identifier table.insert( z.message_tail, { set_error( 'param_access_requires_param', {k:lower}, true ) } );	-- param name is uppercase in cfg.id_handlers (k); lowercase for error message end id_accesses_list[k] = cfg.keywords_xlate[access_level];			-- get translated keyword end end end return id_accesses_list; end

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

Sets local cfg table and 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) cfg = cfg_table_ptr;

is_set = utilities_page_ptr.is_set;											-- import functions from select Module:Citation/Utilities module in_array = utilities_page_ptr.in_array; set_error = utilities_page_ptr.set_error; select_one = utilities_page_ptr.select_one; add_maint_cat = utilities_page_ptr.add_maint_cat; substitute = utilities_page_ptr.substitute; make_wikilink = utilities_page_ptr.make_wikilink;

z = utilities_page_ptr.z;													-- table of tables in Module:Citation/Utilities end

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

return { build_id_list = build_id_list, extract_ids = extract_ids, extract_id_access_levels = extract_id_access_levels, is_embargoed = is_embargoed; set_selected_modules = set_selected_modules; }