Module:Citation/CS1/Identifiers

local identifiers = {};

----< F O R W A R D  D E C L A R A T I O N S >-- local utilities = require ('Module:Citation/CS1/Utilities')

local is_set = utilities.is_set	;												-- functions in Module:Citation/CS1/Utilities local in_array = utilities.in_array; local set_error = utilities.set_error; local select_one = utilities.select_one; local add_maint_cat = utilities.add_maint_cat;

local z ={};																	-- tables in Module:Citation/CS1/Utilities

local cfg = {};																	-- table of configuration tables that are defined in Module:Citation/CS1/Configuration

--[[--< 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; if options.encode == true or options.encode == nil then url_string = mw.uri.encode( url_string ); end return mw.ustring.format( '%s%s[%s%s%s %s]',		options.link, options.label, options.separator or " ",		options.prefix, url_string, options.suffix or "",		mw.text.nowiki(options.id)	); 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) return mw.ustring.format( '%s%s%s',		options.link, options.label, options.separator or " ",		options.prefix, options.id, options.suffix or "",		mw.text.nowiki(options.id)	); 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 check_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

--[[--< C H E C K _ I S B N >

Determines whether an ISBN string is valid

]]

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

if len == 10 then if isbn_str:match( "^%d*X?$" ) == nil then return false; end return is_valid_isxn(isbn_str, 10); else local temp = 0; if isbn_str:match( "^97[89]%d*$" ) == nil then return false; end		-- isbn13 begins with 978 or 979; ismn begins with 979 return is_valid_isxn_13 (isbn_str); end end

--[[--< C H E C K _ 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;

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="" .. handler.label .. "" .. handler.separator .. id;		-- because no place to link to yet

if false == valid_ismn then text = text .. ' ' .. set_error( 'bad_ismn' )							-- add an error message if the issn 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) local issn_copy = id;		-- save a copy of unadulterated issn; use this version for display if issn does not validate local handler = cfg.id_handlers['ISSN']; local text; local valid_issn = true;

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,		prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode}) if false == valid_issn then text = text .. ' ' .. set_error( 'bad_issn' )			-- add an error message if the issn is invalid end return text 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.

]]

local function amazon(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 check_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, prefix=handler.prefix .. domain .. "/dp/",		id=id, encode=handler.encode, separator = handler.separator}) .. err_cat; end

--[[--< 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 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 = ''; local 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]*$"); year = tonumber(year); month = tonumber(month); if ((not (90 year)) or (1 > month or 12 < month)) or		-- if invalid year or invalid month ((91 == year and 7 > month) or (7 == year and 3 < month)) then		-- if years ok, are starting and ending months ok? err_cat = ' ' .. set_error( 'bad_arxiv' );						-- set error message end elseif id:match("^%d%d[01]%d%.%d%d%d%d$") 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 = ' ' .. set_error( 'bad_arxiv' );						-- set 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 = ' ' .. set_error( 'bad_arxiv' );							-- set error message end else err_cat = ' ' .. set_error( 'bad_arxiv' );								-- arXiv id doesn't match any format end

text = external_link_id({link = handler.link, label = handler.label,			prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode}) .. err_cat;

if is_set (class) then class = ' ' .. '//arxiv.org/archive/' .. class .. ' ' .. class .. '';	-- external link within square brackets, not wikilink else class = '';																-- empty string for concatenation end return text .. class; 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

--[[--< 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,			prefix=handler.prefix,id=lccn,separator=handler.separator, encode=handler.encode}) .. err_cat; 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 = 30000000;						-- 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,			prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode}) .. err_cat; 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

--[[--< 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 = 5000000;							-- update this value as PMCs approach local handler = cfg.id_handlers['PMC']; local err_cat = '';								-- presume that PMC is valid local text;

if id:match("[^%d]") then							-- if PMC has anything but digits err_cat = ' ' .. set_error( 'bad_pmc' );			-- set an error message else												-- PMC 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 PMC is outside test limit boundaries err_cat = ' ' .. set_error( 'bad_pmc' );		-- set an error message end end if is_set (embargo) then													-- is PMC is still embargoed? text="" .. handler.label .. ":" .. handler.separator .. id .. err_cat;	-- still embargoed so no external link else text = external_link_id({link = handler.link, label = handler.label,			-- no embargo date or embargo has expired, ok to link to article			prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode}) .. err_cat; 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) 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 text = "" .. handler.label .. ":" .. id; if is_set(inactive_year) then table.insert( z.error_categories, "Pages with DOIs inactive since " .. inactive_year ); else table.insert( z.error_categories, "Pages with inactive DOIs" );	-- when inactive doesn't contain a recognizable year end inactive = " (" .. cfg.messages['inactive'] .. " " .. inactive .. ")" else text = external_link_id({link = handler.link, label = handler.label,			prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode}) inactive = "" end

if nil == id:match("^10%.[^%s–]-/[^%s–]-[^%.,]$") then	-- doi must begin with '10.', must contain a fwd slash, must not contain spaces or endashes, and must not end with period or comma cat = ' ' .. set_error( 'bad_doi' ); end return text .. inactive .. cat 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) local code = id:match("^%d+([AMW])$");										-- only digits followed by 'A', 'M', or 'W'	local handler = cfg.id_handlers['OL'];

if ( code == "A" ) then return external_link_id({link=handler.link, label=handler.label,			prefix=handler.prefix .. 'authors/OL',			id=id, separator=handler.separator,	encode = handler.encode}) elseif ( code == "M" ) then return external_link_id({link=handler.link, label=handler.label,			prefix=handler.prefix .. 'books/OL',			id=id, separator=handler.separator,	encode = handler.encode}) elseif ( code == "W" ) then return external_link_id({link=handler.link, label=handler.label,			prefix=handler.prefix .. 'works/OL',			id=id, separator=handler.separator,	encode = handler.encode}) else return external_link_id({link=handler.link, label=handler.label,			prefix=handler.prefix .. 'OL',			id=id, separator=handler.separator,	encode = handler.encode}) .. ' ' .. set_error( 'bad_ol' ); end end

--[[--< M E S S A G E _ 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 message_id (id) local handler = cfg.id_handlers['USENETID'];

text = external_link_id({link = handler.link, label = handler.label,		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_message_id' )						-- add an error message if the message id is invalid end return text end

--[[--< 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 = {};

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 }, 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 == 'DOI' then table.insert( new_list, {handler.label, doi( v, options.DoiBroken ) } ); elseif k == 'ARXIV' then table.insert( new_list, {handler.label, arxiv( v, options.Class ) } ); elseif k == 'ASIN' then table.insert( new_list, {handler.label, amazon( v, options.ASINTLD ) } ); elseif k == 'LCCN' then table.insert( new_list, {handler.label, lccn( v ) } ); elseif k == 'OL' or k == 'OLA' then table.insert( new_list, {handler.label, openlibrary( v ) } ); 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 == 'ISMN' then table.insert( new_list, {handler.label, ismn( v ) } ); elseif k == 'ISSN' then table.insert( new_list, {handler.label, issn( v ) } ); elseif k == 'ISBN' then local ISBN = internal_link_id( handler ); if not check_isbn( v ) and not is_set(options.IgnoreISBN) then ISBN = ISBN .. set_error( 'bad_isbn', {}, false, " ", "" ); end table.insert( new_list, {handler.label, ISBN } ); elseif k == 'USENETID' then table.insert( new_list, {handler.label, message_id( v ) } ); else error( cfg.messages['unknown_manual_ID'] ); end end function comp( a, b )	-- used in following table.sort return a[1] < b[1]; 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

return { build_id_list = build_id_list, extract_ids = extract_ids, }