Module:Citation/CS1

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

local z = {
	error_categories = {};		-- for categorizing citations that contain errors
	error_ids = {};
	message_tail = {};
	maintenance_cats = {};		-- for categorizing citations that aren't erroneous per se, but could use a little work
	properties_cats = {};		-- for categorizing citations based on certain properties, language of source for instance
}

-- Whether variable is set or not
function is_set( var )
	return not (var == nil or var == '');
end

-- First set variable or nil if none
function first_set(...)
	local list = {...};
	for _, var in pairs(list) do
		if is_set( var ) then
			return var;
		end
	end
end

-- Whether needle is in haystack
function inArray( needle, haystack )
	if needle == nil then
		return false;
	end
	for n,v in ipairs( haystack ) do
		if v == needle then
			return n;
		end
	end
	return false;
end

--[[
Categorize and emit an error message when the citation contains one or more deprecated parameters.  Because deprecated parameters (currently |day=, |month=,
|coauthor=, and |coauthors=) aren't related to each other and because these parameters may be concatenated into the variables used by |date= and |author#= (and aliases)
details of which parameter caused the error message are not provided.  Only one error message is emitted regardless of the number of deprecated parameters in the citation.
]]
function deprecated_parameter()
	if true ~= Page_in_deprecated_cat then	-- if we haven't been here before then set a 
		Page_in_deprecated_cat=true;		-- sticky flag so that if there are more than one deprecated parameter the category is added only once
		table.insert( z.message_tail, { seterror( 'deprecated_params', {}, true ) } );		-- add error message
	end
end

-- Populates numbered arguments in a message string using an argument table.
function substitute( msg, args )
--	return args and tostring( mw.message.newRawMessage( msg, args ) ) or msg;
	return args and mw.message.newRawMessage( msg, args ):plain() or msg;
end

--[[
Apply kerning to open the space between the quote mark provided by the Module and a leading or trailing quote mark contained in a |title= or |chapter= parameter's value.
This function will positive kern  either single or double quotes:
	"'Unkerned title with leading and trailing single quote marks'"
	" 'Kerned title with leading and trailing single quote marks' " (in real life the kerning isn't as wide as this example)
]]
function kern_quotes (str)
	local left='<span style="padding-left:0.2em;">%1</span>';		-- spacing to use when title contains leading single or double quote mark
	local right='<span style="padding-right:0.2em;">%1</span>';		-- spacing to use when title contains trailing single or double quote mark
	
	if  str:match ("^[\"\'][^\']") then
		str = string.gsub( str, "^[\"\']", left, 1 );				-- replace (captured) leading single or double quote with left-side <span>
	end
	if str:match ("[^\'][\"\']$") then
		str = string.gsub( str, "[\"\']$", right, 1 );			-- replace (captured) trailing single or double quote with right-side <span>
	end
	return str;
end

--[[--------------------------< F O R M A T _ S C R I P T _ V A L U E >----------------------------------------

|script-title= holds title parameters that are not written in Latin based scripts: Chinese, Japanese, Arabic, Hebrew, etc. These scripts should
not be italicized and may be written right-to-left.  The value supplied by |script-title= is concatenated onto Title after Title has been wrapped
in italic markup.

Regardless of language, all values provided by |script-title= are wrapped in <bdi>...</bdi> tags to isolate rtl languages from the English left to right.

|script-title= provides a unique feature.  The value in |script-title= may be prefixed with a two-character ISO639-1 language code and a colon:
	|script-title=ja:*** *** (where * represents a Japanese character)
Spaces between the two-character code and the colon and the colon and the first script character are allowed:
	|script-title=ja : *** ***
	|script-title=ja: *** ***
	|script-title=ja :*** ***
Spaces preceding the prefix are allowed: |script-title = ja:*** ***

The prefix is checked for validity.  If it is a valid ISO639-1 language code, the lang attribute (lang="ja") is added to the <bdi> tag so that browsers can
know the language the tag contains.  This may help the browser render the script more correctly.  If the prefix is invalid, the lang attribute
is not added.  At this time there is no error message for this condition.

At this writing, only |script-title= is supported.  It is anticipated that additional parameters will be created to use this function.

TODO: error messages when prefix is invalid ISO639-1 code; when script_value has prefix but no script;
]]

function format_script_value (script_value)
	local lang='';																-- initialize to empty string
	local name;
	if script_value:match('^%l%l%s*:') then										-- if first 3 non-space characters are script language prefix
		lang = script_value:match('^(%l%l)%s*:%s*%S.*');						-- get the language prefix or nil if there is no script
		if not is_set (lang) then
			return '';															-- script_value was just the prefix so return empty string
		end
																				-- if we get this far we have prefix and script
		name = mw.language.fetchLanguageName( lang, "en" );						-- get language name so that we can use it to categorize
		if is_set (name) then													-- is prefix a proper ISO 639-1 language code?
			script_value = script_value:gsub ('^%l%l%s*:%s*', '');				-- strip prefix from script
			if inArray (lang, {'ar', 'ja', 'ko', 'he', 'zh'}) then				-- is prefix one of these language codes?
				table.insert( z.properties_cats, 'CS1 uses ' .. name .. '-language script ('..lang..')');	-- categorize in language-specific categories
			else
				table.insert( z.properties_cats, 'CS1 uses foreign language script');	-- use this category as a catchall until language-specific category is available
			end
			lang = ' lang="' .. lang .. '" ';									-- convert prefix into a lang attribute
		else
			lang = '';															-- invalid so set lang to empty string
		end
	end
	script_value = '<bdi' .. lang .. '>' .. script_value .. '</bdi>';			-- isolate incase script is rlt

	return script_value;
end

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

Initially for |title= and |script-title=, this function concatenates those two parameter values after the script value has been 
wrapped in <bdi> tags.
]]

function script_concatenate (title, script)
	if is_set (script) then
		script = format_script_value (script);									-- <bdi> tags, lang atribute, categorization, etc; returns empty string on error
		if is_set (script) then
			title = title .. ' ' .. script;										-- concatenate title and script title
		end
	end
	return title;
end

-- Wraps a string using a message_list configuration taking one argument
function wrap( key, str, lower )
	if not is_set( str ) then
		return "";
	elseif inArray( key, { 'italic-title', 'trans-italic-title' } ) then
		str = safeforitalics( str );
	end
	if lower == true then
		return substitute( cfg.messages[key]:lower(), {str} );
	else
		return substitute( cfg.messages[key], {str} );
	end		
end

--[[
Argument wrapper.  This function provides support for argument 
mapping defined in the configuration file so that multiple names
can be transparently aliased to single internal variable.
]]
function argument_wrapper( args )
	local origin = {};
	
	return setmetatable({
		ORIGIN = function( self, k )
			local dummy = self[k]; --force the variable to be loaded.
			return origin[k];
		end
	},
	{
		__index = function ( tbl, k )
			if origin[k] ~= nil then
				return nil;
			end
			
			local args, list, v = args, cfg.aliases[k];
			
			if type( list ) == 'table' then
				v, origin[k] = selectone( args, list, 'redundant_parameters' );
				if origin[k] == nil then
					origin[k] = ''; -- Empty string, not nil
				end
			elseif list ~= nil then
				v, origin[k] = args[list], list;
			else
				-- maybe let through instead of raising an error?
				-- v, origin[k] = args[k], k;
				error( cfg.messages['unknown_argument_map'] );
			end
			
			-- Empty strings, not nil;
			if v == nil then
				v = cfg.defaults[k] or '';
				origin[k] = '';
			end
			
			tbl = rawset( tbl, k, v );
			return v;
		end,
	});
end

--[[
Looks for a parameter's name in the whitelist.

Parameters in the whitelist can have three values:
	true - active, supported parameters
	false - deprecated, supported parameters
	nil - unsupported parameters
]]
function validate( name )
	local name = tostring( name );
	local state = whitelist.basic_arguments[ name ];
	
	-- Normal arguments
	if true == state then return true; end		-- valid actively supported parameter
	if false == state then
		deprecated_parameter ();				-- parameter is deprecated but still supported
		return true;
	end
	
	-- Arguments with numbers in them
	name = name:gsub( "%d+", "#" );				-- replace digit(s) with # (last25 becomes last#
	state = whitelist.numbered_arguments[ name ];
	if true == state then return true; end		-- valid actively supported parameter
	if false == state then
		deprecated_parameter ();				-- parameter is deprecated but still supported
		return true;
	end
	
	return false;								-- Not supported because not found or name is set to nil
end

-- Formats a comment for error trapping
function errorcomment( content, hidden )
	return wrap( hidden and 'hidden-error' or 'visible-error', content );
end

--[[
Sets an error condition and returns the appropriate error message.  The actual placement
of the error message in the output is the responsibility of the calling function.
]]
function seterror( error_id, arguments, raw, prefix, suffix )
	local error_state = cfg.error_conditions[ error_id ];
	
	prefix = prefix or "";
	suffix = suffix or "";
	
	if error_state == nil then
		error( cfg.messages['undefined_error'] );
	elseif is_set( error_state.category ) then
		table.insert( z.error_categories, error_state.category );
	end
	
	local message = substitute( error_state.message, arguments );
	
	message = message .. " ([[" .. cfg.messages['help page link'] .. 
		"#" .. error_state.anchor .. "|" ..
		cfg.messages['help page label'] .. "]])";
	
	z.error_ids[ error_id ] = true;
	if inArray( error_id, { 'bare_url_missing_title', 'trans_missing_title' } )
			and z.error_ids['citation_missing_title'] then
		return '', false;
	end
	
	message = table.concat({ prefix, message, suffix });
	
	if raw == true then
		return message, error_state.hidden;
	end		
		
	return errorcomment( message, error_state.hidden );
end

-- Formats a wiki style external link
function externallinkid(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 %s]',
		options.link, options.label, options.separator or "&nbsp;",
		options.prefix, url_string, options.suffix or "",
		mw.text.nowiki(options.id)
	);
end

-- Formats a wiki style internal link
function internallinkid(options)
	return mw.ustring.format( '[[%s|%s]]%s[[%s%s%s|%s]]',
		options.link, options.label, options.separator or "&nbsp;",
		options.prefix, options.id, options.suffix or "",
		mw.text.nowiki(options.id)
	);
end

-- Format an external link with error checking
function externallink( URL, label, source )
	local error_str = "";
	if not is_set( label ) then
		label = URL;
		if is_set( source ) then
			error_str = seterror( 'bare_url_missing_title', { wrap( 'parameter', source ) }, false, " " );
		else
			error( cfg.messages["bare_url_no_origin"] );
		end			
	end
	if not checkurl( URL ) then
		error_str = seterror( 'bad_url', {}, false, " " ) .. error_str;
	end
	return table.concat({ "[", URL, " ", safeforurl( label ), "]", error_str });
end

-- Formats a link to Amazon
function amazon(id, domain)
	if checkisbn( id ) then														-- see if asin value is a 10-digit isbn
		table.insert( z.maintenance_cats, "CS1 maint: ASIN uses ISBN");			-- add to maint category so a bot or awb script can replace |asin= with |isbn=
	end
	if not is_set(domain) then 
		domain = "com";
	elseif inArray (domain, {'jp', 'uk'}) then			-- Japan, United Kingdom
		domain = "co." .. domain;
	elseif inArray (domain, {'au', 'br', 'mx'}) then	-- Australia, Brazil, Mexico
		domain = "com." .. domain;
	end
	local handler = cfg.id_handlers['ASIN'];
	return externallinkid({link = handler.link,
		label=handler.label , prefix="//www.amazon."..domain.."/dp/",id=id,
		encode=handler.encode, separator = handler.separator})
end

--[[
format and error check arXiv identifier.  There are two valid forms of the identifier:
the first form, valid only between date codes 9108 and 0703 is:
	arXiv:<archive>.<class>/<date code><number><version>
where:
	<archive> is a string of alpha characters - may be hyphenated; no other punctuation
	<class> is a string of alpha characters - may be hyphenated; no other punctuation
	<date code> 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
	<number> is a three-digit number
	<version> is a 1 or more digit number preceded with a lowercase v; no spaces (undocumented)
	
the second form, valid from April 2007 is:
	arXiv:<date code>.<number><version>
where:
	<date code> 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
	<number> is a four-digit number
	<version> is a 1 or more digit number preceded with a lowercase v; no spaces
]]

function arxiv (id)
	local handler = cfg.id_handlers['ARXIV'];
	local year, month, version;
	local err_cat = ""
	
	year, month, version = id:match("^%a[%a%.%-]+/([90]%d)([01]%d)%d%d%d([v%d]*)$");				-- test for the 9108-0703 format
	if not year then		-- arXiv id is not proper 9108-0703 form
		year, month, version = id:match("^(%d%d)([01]%d)%.%d%d%d%d([v%d]*)$");	-- test for the 0704- format
		if not year then	
			err_cat = ' ' .. seterror( 'bad_arxiv' );							-- arXiv id doesn't match either format
		else	-- id is the 0704- format
			year = tonumber(year);
			month = tonumber(month);
			if ((7 > year) or (1 > month and 12 < month)) or					-- is year invalid or is month invalid? (doesn't test for future years)
				((7 == year) and (4 > month)) or								-- when year is 07, is month invalid (before April)?
				is_set (version) and nil == version:match("v%d+") then			-- is version proper format of single 'v' followed by digits?
					err_cat = ' ' .. seterror( 'bad_arxiv' );					-- set error message
			end
		end
	else	-- id is the 9108-0703 format; are the date values ok
		year = tonumber(year);
		month = tonumber(month);
		if ((91 > year and 7 < year) or (1 > month and 12 < month)) or			-- if invalid year or invalid month
			((91 == year and 8 > month) or (7 == year and 3 < month)) or 		-- if years ok, are starting and ending months ok?
				is_set (version) and nil == version:match("v%d+") then			-- is version proper format of single 'v' followed by digits?
					err_cat = ' ' .. seterror( 'bad_arxiv' );					-- set error message
		end
	end

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

--[[
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.
]]

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

--[[
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

]]
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 = ' ' .. seterror( '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 = ' ' .. seterror( '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 = ' ' .. seterror( '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 = ' ' .. seterror( '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 = ' ' .. seterror( 'bad_lccn' );	-- no match, set an error message
		end
	else
		err_cat = ' ' .. seterror( 'bad_lccn' );		-- wrong length, set an error message
	end

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

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

--[[
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.
]]
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 = ' ' .. seterror( '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 = ' ' .. seterror( 'bad_pmid' );	-- set an error message
		end
	end
	
	return externallinkid({link = handler.link, label = handler.label,
			prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode}) .. err_cat;
end

--[[
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 true; otherwise, returns false because the embargo has expired or |embargo= not set in this cite.
]]
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 and tonumber( embargo_date ) >= tonumber( todays_date ) then	--is embargo date is in the future?
			return true;	-- still embargoed
		end
	end
	return false;			-- embargo expired or |embargo= not set
end

--[[
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 specifies a date 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.

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.
]]
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 = ' ' .. seterror( '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 = ' ' .. seterror( 'bad_pmc' );		-- set an error message
		end
	end
	
	if is_embargoed(embargo) then
		text="[[" .. handler.link .. "|" .. handler.label .. "]]:" .. handler.separator .. id .. err_cat;	--still embargoed so no external link
	else
		text = externallinkid({link = handler.link, label = handler.label,			--no embargo date, ok to link to article
			prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode}) .. err_cat;
	end
	return text;
end

-- 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.

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.link .. "|" .. 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 = externallinkid({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 = ' ' .. seterror( 'bad_doi' );
	end
	return text .. inactive .. cat 
end

-- Formats an OpenLibrary link, and checks for associated errors.
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 externallinkid({link=handler.link, label=handler.label,
			prefix="http://openlibrary.org/authors/OL",id=id, separator=handler.separator,
			encode = handler.encode})
	elseif ( code == "M" ) then
		return externallinkid({link=handler.link, label=handler.label,
			prefix="http://openlibrary.org/books/OL",id=id, separator=handler.separator,
			encode = handler.encode})
	elseif ( code == "W" ) then
		return externallinkid({link=handler.link, label=handler.label,
			prefix= "http://openlibrary.org/works/OL",id=id, separator=handler.separator,
			encode = handler.encode})
	else
		return externallinkid({link=handler.link, label=handler.label,
			prefix= "http://openlibrary.org/OL",id=id, separator=handler.separator,
			encode = handler.encode}) .. 
			' ' .. seterror( 'bad_ol' );
	end
end

--[[
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: [http://www.worldcat.org/issn/0819 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.
]]
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 = externallinkid({link = handler.link, label = handler.label,
		prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode})
 
	if false == valid_issn then
		text = text .. ' ' .. seterror( 'bad_issn' )			-- add an error message if the issn is invalid
	end 
	
	return text
end

--[[
This function sets default title types (equivalent to the citation including |type=<default value>) for those citations that have defaults.
Also handles the special case where it is desirable to omit the title type from the rendered citation (|type=none).
]]
function set_titletype(cite_class, title_type)
	if is_set(title_type) then
		if "none" == title_type then
			title_type = "";					-- if |type=none then type parameter not displayed
		end
		return title_type;						-- if |type= has been set to any other value use that value
	end

	if "AV-media-notes" == cite_class or "DVD-notes" == cite_class then		-- if this citation is cite AV media notes or cite DVD notes
		return "Media notes";					-- display AV media notes / DVD media notes annotation

	elseif "podcast" == cite_class then			-- if this citation is cite podcast
		return "Podcast";						-- display podcast annotation

	elseif "pressrelease" == cite_class then	-- if this citation is cite press release
		return "Press release";					-- display press release annotation

	elseif "techreport" == cite_class then		-- if this citation is cite techreport
		return "Technical report";				-- display techreport annotation
	
	elseif "thesis" == cite_class then			-- if this citation is cite thesis (degree option handled after this function returns)
			return "Thesis";					-- display simple thesis annotation (without |degree= modification)
	end
end

--[[
Determines whether a URL string is valid

At present the only check is whether the string appears to 
be prefixed with a URI scheme.  It is not determined whether 
the URI scheme is valid or whether the URL is otherwise well 
formed.
]]
function checkurl( url_str )
	-- Protocol-relative or URL scheme
	return url_str:sub(1,2) == "//" or url_str:match( "^[^/]*:" ) ~= nil;
end

-- Removes irrelevant text and dashes from ISBN number
-- Similar to that used for Special:BookSources
function cleanisbn( isbn_str )
	return isbn_str:gsub( "[^-0-9X]", "" );
end


--[[
Strip wiki italic and bold markup from argument so that it doesn't contaminate COinS metadata
This function strips common patterns of apostrophe markup.  We presume that editors who have taken the time to
markup a title have, as a result, provided valid markup.
]]
function strip_apostrophe_markup (argument)
	local pattern, c1, c2;
	if not is_set (argument) then return argument; end
	
	while true do																-- look for and remove all 5-apostrophe (bold and italic) markup
		if argument:match ("%'%'%'%'%'") then										-- is there an instance of bold-italic?
			if argument:match ("%'%'%'%'%'.*%'%'%'%'%'") then						-- 5, 5
				pattern, c1 = argument:match ("(%'%'%'%'%'(.*)%'%'%'%'%')");		
				c2 = "";														-- set to empty string so we do only one replacement at end
			elseif argument:match ("%'%'%'%'%'.*%'%'%'.*%'%'") then				-- bold italic followed by italic (5, 3, 2)
				pattern, c1, c2 = argument:match ("(%'%'%'%'%'(.*)%'%'%'(.*)%'%')");
			elseif argument:match ("%'%'%'%'%'.*%'%'.*%'%'%'") then				-- bold italic followed by bold (5, 2, 3)
				pattern, c1, c2 = argument:match ("(%'%'%'%'%'(.*)%'%'(.*)%'%'%')");
			elseif argument:match ("%'%'%'.*%'%'.*%'%'%'%'%'") then				-- bold italic followed by italic (3, 2, 5)
				pattern, c1, c2 = argument:match ("(%'%'%'(.*)%'%'(.*)%'%'%'%'%')");
			elseif argument:match ("%'%'.*%'%'%'.*%'%'%'%'%'") then				-- italic followed by bold (2, 3, 5)
				pattern, c1, c2 = argument:match ("(%'%'(.*)%'%'%'(.*)%'%'%'%'%')");
			end
			pattern = pattern:gsub("([%^%$%(%)%%%.%[%]%*%+%-%?])", "%%%1");		-- pattern is not a literal string; escape lua's magic pattern characters
			argument=argument:gsub(pattern, c1..c2);							-- remove the markup
		else
			break;																-- none or no more 5-apostrophe matches
		end
	end
	while true do																-- look for and remove all 3-apostrophe (bold) markup
		if argument:match ("%'%'%'.*%'%'%'") then								-- is there an instance of bold?
			pattern, c1 = argument:match ("(%'%'%'(.*)%'%'%')")
			pattern = pattern:gsub("([%^%$%(%)%%%.%[%]%*%+%-%?])", "%%%1");	-- pattern is not a literal string; escape lua's magic pattern characters
			argument=argument:gsub(pattern, c1);								-- remove the markup
		else
			break;																-- none or no more 3 matches
		end
	end
	while true do																-- look for and remove all 2-apostrophe (italic) markup
		if argument:match ("%'%'.*%'%'") then									-- is there an instance of italic?
			pattern, c1 = argument:match ("(%'%'(.*)%'%')")
			pattern = pattern:gsub("([%^%$%(%)%%%.%[%]%*%+%-%?])", "%%%1");	-- pattern is not a literal string; escape lua's magic pattern characters
			argument=argument:gsub(pattern, c1);								-- remove the markup
		else
			break;																-- none or no more 2 matches
		end
	end
	return argument;															-- done
end

--[[--------------------------< M A K E _ C O I N S _ T I T L E >----------------------------------------------

Makes a title for COinS from Title and / or ScriptTitle (or any other name-script pairs)

Apostrophe markup (bold, italics) is stripped from each value so that the COinS metadata isn't correupted with strings
of %27%27...
]]

function make_coins_title (title, script)
	if is_set (title) then
		title = strip_apostrophe_markup (title);								-- strip any apostrophe markup
	else
		title='';																-- if not set, make sure title is an empty string
	end
	if is_set (script) then
		script = script:gsub ('^%l%l%s*:%s*', '');								-- remove language prefix if present (script value may now be empty string)
		script = strip_apostrophe_markup (script);								-- strip any apostrophe markup
	else
		script='';																-- if not set, make sure script is an empty string
	end
	if is_set (title) and is_set (script) then
		script = ' ' .. script;													-- add a space before we concatenate
	end
	return title .. script;														-- return the concatenation
end

-- Extract page numbers from external wikilinks in any of the |page=, |pages=, or |at= parameters for use in COinS.
function get_coins_pages (pages)
	local pattern;
	if not is_set (pages) then return pages; end			-- if no page numbers then we're done
	
	while true do
		pattern = pages:match("%[(%w*:?//[^ ]+%s+)[%w%d].*%]");	-- pattern is the opening bracket, the url and following space(s): "[url "
		if nil == pattern then break; end					-- no more urls
		pattern = pattern:gsub("([%^%$%(%)%%%.%[%]%*%+%-%?])", "%%%1");	-- pattern is not a literal string; escape lua's magic pattern characters
		pages = pages:gsub(pattern, "");					-- remove as many instances of pattern as possible
	end
	pages = pages:gsub("[%[%]]", "");						-- remove the brackets
	pages = pages:gsub("–", "-" );							-- replace endashes with hyphens
	pages = pages:gsub("&%w+;", "-" );						-- and replace html entities (&ndash; etc.) with hyphens; do we need to replace numerical entities like &#32; and the like?
	return pages;
end

--[[
ISBN-10 and ISSN validator code calculates checksum across all isbn/issn digits including the check digit. ISBN-13 is checked in checkisbn().
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.
]]
function is_valid_isxn (isxn_str, len)
	local temp = 0;
	isxn_str = { isxn_str:byte(1, len) };	-- make a table of bytes
	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
			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

-- Determines whether an ISBN string is valid
function checkisbn( 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
		isbn_str = { isbn_str:byte(1, len) };
		for i, v in ipairs( isbn_str ) do
			temp = temp + (3 - 2*(i % 2)) * tonumber( string.char(v) );
		end
		return temp % 10 == 0;
	end
end

-- Gets the display text for a wikilink like [[A|B]] or [[B]] gives B
function removewikilink( str )
	return (str:gsub( "%[%[([^%[%]]*)%]%]", function(l)
		return l:gsub( "^[^|]*|(.*)$", "%1" ):gsub("^%s*(.-)%s*$", "%1");
	end));
end

-- Escape sequences for content that will be used for URL descriptions
function safeforurl( str )
	if str:match( "%[%[.-%]%]" ) ~= nil then 
		table.insert( z.message_tail, { seterror( 'wikilink_in_url', {}, true ) } );
	end
	
	return str:gsub( '[%[%]\n]', {	
		['['] = '&#91;',
		[']'] = '&#93;',
		['\n'] = ' ' } );
end

-- Converts a hyphen to a dash
function hyphentodash( str )
	if not is_set(str) or str:match( "[%[%]{}<>]" ) ~= nil then
		return str;
	end	
	return str:gsub( '-', '–' );
end

-- Protects a string that will be wrapped in wiki italic markup '' ... ''
function safeforitalics( str )
	--[[ Note: We cannot use <i> for italics, as the expected behavior for
	italics specified by ''...'' in the title is that they will be inverted
	(i.e. unitalicized) in the resulting references.  In addition, <i> and ''
	tend to interact poorly under Mediawiki's HTML tidy. ]]
	
	if not is_set(str) then
		return str;
	else
		if str:sub(1,1) == "'" then str = "<span />" .. str; end
		if str:sub(-1,-1) == "'" then str = str .. "<span />"; end
		
		-- Remove newlines as they break italics.
		return str:gsub( '\n', ' ' );
	end
end

--[[
Joins a sequence of strings together while checking for duplicate separation characters.

TODO: safejoin() has a flaw where it won't remove the duplicate character from a |title= / |url= combination.
This is because by the time we get here, |title=http://somesite.com and |title=Document Title. have been combined:
	[http://somesite.com and ''Document Title.'']
so that now, the last character is not sepc but is ] (unless sepc == ']' which breaks the external link)
]]
function safejoin( tbl, duplicate_char )
	--[[
	Note: we use string functions here, rather than ustring functions.
	
	This has considerably faster performance and should work correctly as 
	long as the duplicate_char is strict ASCII.  The strings
	in tbl may be ASCII or UTF8.
	]]
	
	local str = '';
	local comp = '';
	local end_chr = '';
	local trim;
	for _, value in ipairs( tbl ) do
		if value == nil then value = ''; end
		
		if str == '' then
			str = value;
		elseif value ~= '' then
			if value:sub(1,1) == '<' then
				-- Special case of values enclosed in spans and other markup.
				comp = value:gsub( "%b<>", "" );
			else
				comp = value;
			end
			
			if comp:sub(1,1) == duplicate_char then
				trim = false;
				end_chr = str:sub(-1,-1);
				-- str = str .. "<HERE(enchr=" .. end_chr.. ")"
				if end_chr == duplicate_char then
					str = str:sub(1,-2);
				elseif end_chr == "'" then
					if str:sub(-3,-1) == duplicate_char .. "''" then
						str = str:sub(1, -4) .. "''";
					elseif str:sub(-5,-1) == duplicate_char .. "]]''" then
						trim = true;
					elseif str:sub(-4,-1) == duplicate_char .. "]''" then
						trim = true;
					end
				elseif end_chr == "]" then
					if str:sub(-3,-1) == duplicate_char .. "]]" then
						trim = true;
					elseif str:sub(-2,-1) == duplicate_char .. "]" then
						trim = true;
					end
				elseif end_chr == " " then
					if str:sub(-2,-1) == duplicate_char .. " " then
						str = str:sub(1,-3);
					end
				end

				if trim then
					if value ~= comp then 
						local dup2 = duplicate_char;
						if dup2:match( "%A" ) then dup2 = "%" .. dup2; end
						
						value = value:gsub( "(%b<>)" .. dup2, "%1", 1 )
					else
						value = value:sub( 2, -1 );
					end
				end
			end
			str = str .. value;
		end
	end
	return str;
end  

-- Attempts to convert names to initials.
function reducetoinitials(first)
	local initials = {}
	local i = 0;										-- counter for number of initials
	for word in string.gmatch(first, "%S+") do
		table.insert(initials, string.sub(word,1,1))	-- Vancouver format does not include full stops.
		i = i + 1;										-- bump the counter 
		if 2 <= i then break; end						-- only two initials allowed in Vancouver system; if 2, quit
	end
	return table.concat(initials)						-- Vancouver format does not include spaces.
end

-- Formats a list of people (e.g. authors / editors) 
function listpeople(control, people)
	local sep = control.sep;
	local namesep = control.namesep
	local format = control.format
	local maximum = control.maximum
	local lastauthoramp = control.lastauthoramp;
	local text = {}
	local etal = false;
	
	if sep:sub(-1,-1) ~= " " then sep = sep .. " " end
	if maximum ~= nil and maximum < 1 then return "", 0; end
	
	for i,person in ipairs(people) do
		if is_set(person.last) then
			local mask = person.mask
			local one
			local sep_one = sep;
			if maximum ~= nil and i > maximum then
				etal = true;
				break;
			elseif (mask ~= nil) then
				local n = tonumber(mask)
				if (n ~= nil) then
					one = string.rep("&mdash;",n)
				else
					one = mask;
					sep_one = " ";
				end
			else
				one = person.last
				local first = person.first
				if is_set(first) then 
					if ( "vanc" == format ) then first = reducetoinitials(first) end
					one = one .. namesep .. first 
				end
				if is_set(person.link) and person.link ~= control.page_name then
					one = "[[" .. person.link .. "|" .. one .. "]]"		-- link author/editor if this page is not the author's/editor's page
				end

				if is_set(person.link) and nil ~= person.link:find("//") then one = one .. " " .. seterror( 'bad_authorlink' ) end	-- check for url in author link;
			end
			table.insert( text, one )
			table.insert( text, sep_one )
		end
	end

	local count = #text / 2;
	if count > 0 then 
		if count > 1 and is_set(lastauthoramp) and not etal then
			text[#text-2] = " & ";
		end
		text[#text] = nil; 
	end
	
	local result = table.concat(text) -- construct list
	if etal then 
		local etal_text = cfg.messages['et al'];
		result = result .. " " .. etal_text;
	end
	
	-- if necessary wrap result in <span> tag to format in Small Caps
	if ( "scap" == format ) then result = 
		'<span class="smallcaps" style="font-variant:small-caps">' .. result .. '</span>';
	end 
	return result, count
end

-- Generates a CITEREF anchor ID.
function anchorid( options )
	return "CITEREF" .. table.concat( options );
end

--[[
Gets name list from the input arguments

Searches through args in sequential order to find |lastn= and |firstn= parameters (or their aliases), and their matching link and mask parameters.
Stops searching when both |lastn= and |firstn= are not found in args after two sequential attempts: found |last1=, |last2=, and |last3= but doesn't
find |last4= and |last5= then the search is done.

This function emits an error message when there is a |firstn= without a matching |lastn=.  When there are 'holes' in the list of last names, |last1= and |last3=
are present but |last2= is missing, an error message is emitted. |lastn= is not required to have a matching |firstn=.
]]
function extractnames(args, list_name)
	local names = {};			-- table of names
	local last;					-- individual name components
	local first;
	local link;
	local mask;
	local i = 1;				-- loop counter/indexer
	local n = 1;				-- output table indexer
	local count = 0;			-- used to count the number of times we haven't found a |last= (or alias for authors, |editor-last or alias for editors)
	
	local err_msg_list_name = list_name:match ("(%w+)List") .. 's list';		-- modify AuthorList or EditorList for use in error messages if necessary

	while true do
		last = selectone( args, cfg.aliases[list_name .. '-Last'], 'redundant_parameters', i );		-- search through args for name components beginning at 1
		first = selectone( args, cfg.aliases[list_name .. '-First'], 'redundant_parameters', i );
		link = selectone( args, cfg.aliases[list_name .. '-Link'], 'redundant_parameters', i );
		mask = selectone( args, cfg.aliases[list_name .. '-Mask'], 'redundant_parameters', i );

		if first and not last then												-- if there is a firstn without a matching lastn
			table.insert( z.message_tail, { seterror( 'first_missing_last', {err_msg_list_name, i}, true ) } );	-- add this error message
		elseif not first and not last then										-- if both firstn and lastn aren't found, are we done?
			count = count + 1;													-- number of times we haven't found last and first
			if 2 == count then													-- two missing names and we give up
				break;															-- normal exit or there is a two-name hole in the list; can't tell which
			end
		else																	-- we have last with or without a first
			names[n] = {last = last, first = first, link = link, mask = mask};	-- add this name to our names list
			n = n + 1;															-- point to next location in the names table
			if 1 == count then													-- if the previous name was missing
				table.insert( z.message_tail, { seterror( 'missing_name', {err_msg_list_name, i-1}, true ) } );		-- add this error message
			end
			count = 0;															-- reset the counter, we're looking for two consecutive missing names
		end
		i = i + 1;																-- point to next args location
	end
	return names;																-- all done, return our list of names
end

-- Populates ID table from arguments using configuration settings
function extractids( args )
	local id_list = {};
	for k, v in pairs( cfg.id_handlers ) do	
		v = selectone( args, v.parameters, 'redundant_parameters' );
		if is_set(v) then id_list[k] = v; end
	end
	return id_list;
end

-- Takes a table of IDs and turns it into a table of formatted ID outputs.
function buildidlist( 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
		-- fallback to read-only cfg
		handler = setmetatable( { ['id'] = v }, fallback(k) );
		
		if handler.mode == 'external' then
			table.insert( new_list, {handler.label, externallinkid( handler ) } );
		elseif handler.mode == 'internal' then
			table.insert( new_list, {handler.label, internallinkid( 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 ) } ); 
		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' 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 == 'ISSN' then
			table.insert( new_list, {handler.label, issn( v ) } );
		elseif k == 'ISBN' then
			local ISBN = internallinkid( handler );
			if not checkisbn( v ) and not is_set(options.IgnoreISBN) then
				ISBN = ISBN .. seterror( 'bad_isbn', {}, false, " ", "" );
			end
			table.insert( new_list, {handler.label, ISBN } );				
		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
  
-- Chooses one matching parameter from a list of parameters to consider
-- Generates an error if more than one match is present.
function selectone( args, possible, error_condition, index )
	local value = nil;
	local selected = '';
	local error_list = {};
	
	if index ~= nil then index = tostring(index); end
	
	-- Handle special case of "#" replaced by empty string
	if index == '1' then
		for _, v in ipairs( possible ) do
			v = v:gsub( "#", "" );
			if is_set(args[v]) then
				if value ~= nil and selected ~= v then
					table.insert( error_list, v );
				else
					value = args[v];
					selected = v;
				end
			end
		end		
	end
	
	for _, v in ipairs( possible ) do
		if index ~= nil then
			v = v:gsub( "#", index );
		end
		if is_set(args[v]) then
			if value ~= nil and selected ~=  v then
				table.insert( error_list, v );
			else
				value = args[v];
				selected = v;
			end
		end
	end
	
	if #error_list > 0 then
		local error_str = "";
		for _, k in ipairs( error_list ) do
			if error_str ~= "" then error_str = error_str .. cfg.messages['parameter-separator'] end
			error_str = error_str .. wrap( 'parameter', k );
		end
		if #error_list > 1 then
			error_str = error_str .. cfg.messages['parameter-final-separator'];
		else
			error_str = error_str .. cfg.messages['parameter-pair-separator'];
		end
		error_str = error_str .. wrap( 'parameter', selected );
		table.insert( z.message_tail, { seterror( error_condition, {error_str}, true ) } );
	end
	
	return value, selected;
end

-- COinS metadata (see <http://ocoins.info/>) allows automated tools to parse
-- the citation information.
function COinS(data)
	if 'table' ~= type(data) or nil == next(data) then
		return '';
	end
	
	local ctx_ver = "Z39.88-2004";
	
	-- treat table strictly as an array with only set values.
	local OCinSoutput = setmetatable( {}, {
		__newindex = function(self, key, value)
			if is_set(value) then
				rawset( self, #self+1, table.concat{ key, '=', mw.uri.encode( removewikilink( value ) ) } );
			end
		end
	});
	
	if is_set(data.Chapter) then
		OCinSoutput.rft_val_fmt = "info:ofi/fmt:kev:mtx:book";
		OCinSoutput["rft.genre"] = "bookitem";
		OCinSoutput["rft.btitle"] = data.Chapter;
		OCinSoutput["rft.atitle"] = data.Title;
	elseif is_set(data.Periodical) then
		OCinSoutput.rft_val_fmt = "info:ofi/fmt:kev:mtx:journal";
		OCinSoutput["rft.genre"] = "article";
		OCinSoutput["rft.jtitle"] = data.Periodical;
		OCinSoutput["rft.atitle"] = data.Title;
	else
		OCinSoutput.rft_val_fmt = "info:ofi/fmt:kev:mtx:book";
		OCinSoutput["rft.genre"] = "book"
		OCinSoutput["rft.btitle"] = data.Title;
	end
	
	OCinSoutput["rft.place"] = data.PublicationPlace;
	OCinSoutput["rft.date"] = data.Date;
	OCinSoutput["rft.series"] = data.Series;
	OCinSoutput["rft.volume"] = data.Volume;
	OCinSoutput["rft.issue"] = data.Issue;
	OCinSoutput["rft.pages"] = data.Pages;
	OCinSoutput["rft.edition"] = data.Edition;
	OCinSoutput["rft.pub"] = data.PublisherName;
	
	for k, v in pairs( data.ID_list ) do
		local id, value = cfg.id_handlers[k].COinS;
		if k == 'ISBN' then value = cleanisbn( v ); else value = v; end
		if string.sub( id or "", 1, 4 ) == 'info' then
			OCinSoutput["rft_id"] = table.concat{ id, "/", v };
		else
			OCinSoutput[ id ] = value;
		end
	end
	
	local last, first;
	for k, v in ipairs( data.Authors ) do
		last, first = v.last, v.first;
		if k == 1 then
			if is_set(last) then
				OCinSoutput["rft.aulast"] = last;
			end
			if is_set(first) then 
				OCinSoutput["rft.aufirst"] = first;
			end
		end
		if is_set(last) and is_set(first) then
			OCinSoutput["rft.au"] = table.concat{ last, ", ", first };
		elseif is_set(last) then
			OCinSoutput["rft.au"] = last;
		end
	end
	
	OCinSoutput.rft_id = data.URL;
	OCinSoutput.rfr_id = table.concat{ "info:sid/", mw.site.server:match( "[^/]*$" ), ":", data.RawPage };
	OCinSoutput = setmetatable( OCinSoutput, nil );
	
	-- sort with version string always first, and combine.
	table.sort( OCinSoutput );
	table.insert( OCinSoutput, 1, "ctx_ver=" .. ctx_ver );  -- such as "Z39.88-2004"
	return table.concat(OCinSoutput, "&");
end


--[[--------------------------< G E T _ I S O 6 3 9 _ C O D E >------------------------------------------------

Validates language names provided in |language= parameter if not an ISO639-1 code.  Handles the special case that is Norwegian where
ISO639-1 code 'no' is mapped to language name 'Norwegian Bokmål' by Extention:CLDR.

Returns the language name and associated ISO639-1 code.  Because case of the source may be incorrect or different from the case that Wikimedia
uses, the name comparisons are done in lower case and when a match is found, the Wikimedia version (assumed to be correct) is returned along
with the code.  When there is no match, we return the original language name string.

mw.language.fetchLanguageNames() will return a list of languages that aren't part of ISO639-1. Names that aren't ISO639-1 but that are included
in the list will be found if that name is provided in the |language= parameter.  For example, if |language=Samaritan Aramaic, that name will be
found with the associated code 'sam', not an ISO639-1 code.  When names are found and the associated code is not two characters, this function
returns only the Wikimedia language name.

Adapted from code taken from Module:Check ISO 639-1.
]]

function get_iso639_code (lang)
	if 'Norwegian' == lang then
		return lang, 'no';														-- special case related to Wikimedia remap of code 'no' at Extension:CLDR
	end
	
	local languages = mw.language.fetchLanguageNames('en', 'all')				-- get a list of language names known to Wikimedia
																				-- ('all' is required for North Ndebele, South Ndebele, and Ojibwa)
	local langlc = mw.ustring.lower(lang);										-- lower case version for comparisons
	
	for code, name in pairs(languages) do										-- scan the list to see if we can find our language
		if langlc == mw.ustring.lower(name) then
			if 2 ~= code:len() then												-- ISO639-1 codes only
				return name;													-- so return the name but not the code
			end
			return name, code;													-- found it, return name to ensure proper capitalization and the ISO639-1 code
		end
	end
	return lang;																-- not valid language; return language in original case and nil for ISO639-1 code
end

--[[--------------------------< L A N G U A G E _ P A R A M E T E R >------------------------------------------

Get language name from ISO639-1 code value provided.  If a code is valid use the returned name; if not, then use the value that was provided with the language parameter.

There is an exception.  There are three ISO639-1 codes for Norewegian language variants.  There are two official variants: Norwegian Bokmål (code 'nb') and
Norwegian Nynorsk (code 'nn').  The third, code 'no',  is defined by ISO639-1 as 'Norwegian' though in Norway this is pretty much meaningless.  However, it appears
that on enwiki, editors are for the most part unaware of the nb and nn variants (compare page counts for these variants at Category:Articles with non-English-language external links.

Because Norwegian Bokmål is the most common language variant, Media wiki has been modified to return Norwegian Bokmål for ISO639-1 code 'no'. Here we undo that and
return 'Norwegian' when editors use |language=no.  We presume that editors don't know about the variants or can't descriminate between them.

See Help talk:Citation Style_1#An ISO 639-1 language name test

When |language= contains a valid ISO639-1 code, the page is assigned to the category for that code: Category:Norwegian-language sources (no) if
the page is a mainspace page and the ISO639-1 code is not 'en'.  Similarly, if the  parameter is |language=Norwegian, it will be categorized in the same way.

TODO: Error message when language or language code is not ISO639-1?
]]

function language_parameter (lang, namespace)
	local code;			-- the ISO639-1 two character code
	local name;			-- the language name
	local test='';
		
	if 0 == namespace and (('en' == lang:lower()) or ('english' == lang:lower())) then
		table.insert (z.maintenance_cats, 'CS1 maint: English language specified');		-- add maintenance category if |language=English or |language=en in article space
	end

	if 2 == lang:len() then														-- ISO639-1 language code are 2 characters (fetchLanguageName also supports 3 character codes)
		name = mw.language.fetchLanguageName( lang:lower(), "en" );				-- get ISO 639-1 language name if Language is a proper code
	end

	if is_set (name) then														-- if Language specified a valid ISO639-1 code
		code = lang:lower();													-- save it
	else
		name, code = get_iso639_code (lang);									-- attempt to get code from name (assign name here so that we are sure of proper capitalization)
	end

	if is_set (code) then
		if 'no' == code then name = 'Norwegian' end;							-- override wikimedia when code is 'no'
			if 0 == namespace and 'en' ~= code then					-- is this page main / article space and English not the language?
				table.insert( z.properties_cats, 'CS1 ' .. name .. '-language sources (' .. code .. ')');	-- in main space and not English: categorize
			end
		end
	return (" " .. wrap( 'language', name));									-- wrap with '(in ...)'
end




--[[--------------------------< C I T A T I O N 0 >------------------------------------------------------------
This is the main function doing the majority of the citation
formatting.
]]
function citation0( config, args)
	--[[ 
	Load Input Parameters
	The argument_wrapper facilitates the mapping of multiple
	aliases to single internal variable.
	]]
	local A = argument_wrapper( args );

	local i 
	local PPrefix = A['PPrefix']
	local PPPrefix = A['PPPrefix']
	if is_set( A['NoPP'] ) then PPPrefix = "" PPrefix = "" end
	
	-- Pick out the relevant fields from the arguments.  Different citation templates
	-- define different field names for the same underlying things.	
	local Authors = A['Authors'];
	local a = extractnames( args, 'AuthorList' );

	local Coauthors = A['Coauthors'];
	local Others = A['Others'];
	local Editors = A['Editors'];
	local e = extractnames( args, 'EditorList' );

	local Year = A['Year'];
	local PublicationDate = A['PublicationDate'];
	local OrigYear = A['OrigYear'];
	local Date = A['Date'];
	local LayDate = A['LayDate'];
	------------------------------------------------- Get title data
	local Title = A['Title'];
	local ScriptTitle = A['ScriptTitle'];
	local BookTitle = A['BookTitle'];
	local Conference = A['Conference'];
	local TransTitle = A['TransTitle'];
	local TitleNote = A['TitleNote'];
	local TitleLink = A['TitleLink'];
	local Chapter = A['Chapter'];
	local ChapterLink = A['ChapterLink'];
	local TransChapter = A['TransChapter'];
	local TitleType = A['TitleType'];
	local Degree = A['Degree'];
	local Docket = A['Docket'];
	local ArchiveURL = A['ArchiveURL'];
	local URL = A['URL']
	local URLorigin = A:ORIGIN('URL');
	local ChapterURL = A['ChapterURL'];
	local ChapterURLorigin = A:ORIGIN('ChapterURL');
	local ConferenceURL = A['ConferenceURL'];
	local ConferenceURLorigin = A:ORIGIN('ConferenceURL');
	local Periodical = A['Periodical'];

	local Series = A['Series'];
	local Volume = A['Volume'];
	local Issue = A['Issue'];
	local Position = '';
	local Page = A['Page'];
	local Pages = hyphentodash( A['Pages'] );	
	local At = A['At'];

	local Edition = A['Edition'];
	local PublicationPlace = A['PublicationPlace']
	local Place = A['Place'];
	
	local PublisherName = A['PublisherName'];
	local RegistrationRequired = A['RegistrationRequired'];
	local SubscriptionRequired = A['SubscriptionRequired'];
	local Via = A['Via'];
	local AccessDate = A['AccessDate'];
	local ArchiveDate = A['ArchiveDate'];
	local Agency = A['Agency'];
	local DeadURL = A['DeadURL']
	local Language = A['Language'];
	local Format = A['Format'];
	local Ref = A['Ref'];
	local DoiBroken = A['DoiBroken'];
	local ID = A['ID'];
	local ASINTLD = A['ASINTLD'];
	local IgnoreISBN = A['IgnoreISBN'];
	local Embargo = A['Embargo'];

	local ID_list = extractids( args );
--[[ Hide unfinished cite newsgroup code so that long delayed update can take place
	-- special case for cite newsgroup which uses |id= for a usenet article or post id
	-- |id= is not included in COinS so here we convert it to an ID that will be included in COinS
	if ('newsgroup' == config.CitationClass) and (is_set (ID)) then
		ID_list['USENETID']=ID;			-- add this new 'id' to the list of IDs
		ID = '';						-- and unset
	end
]]	
	local Quote = A['Quote'];
	local PostScript = A['PostScript'];

	local LayURL = A['LayURL'];
	local LaySource = A['LaySource'];
	local Transcript = A['Transcript'];
	local TranscriptURL = A['TranscriptURL'] 
	local TranscriptURLorigin = A:ORIGIN('TranscriptURL');
	local sepc = A['Separator'];

	local LastAuthorAmp = A['LastAuthorAmp'];
	local no_tracking_cats = A['NoTracking'];

--these are used by cite interview
	local Callsign = A['Callsign'];
	local City = A['City'];
	local Cointerviewers = A['Cointerviewers'];			-- deprecated
	local Interviewer = A['Interviewer'];				-- deprecated
	local Program = A['Program'];

--local variables that are not cs1 parameters
	local page_type;									-- is this needed?  Doesn't appear to be used anywhere;
	local use_lowercase = ( sepc ~= '.' );
	local this_page = mw.title.getCurrentTitle();		--Also used for COinS and for language
	local anchor_year;									-- used in the CITEREF identifier
	local COinS_date;									-- used in the COinS metadata

-- Set postscript default.
	if not is_set (PostScript) then						-- if |postscript= has not been set (Postscript is nil which is the default for {{citation}}) and
		if (config.CitationClass ~= "citation") then	-- this template is not a citation template
			PostScript = '.';							-- must be a cite xxx template so set postscript to default (period)
		end
	else
		if PostScript:lower() == 'none' then			-- if |postscript=none then
			PostScript = '';							-- no postscript
		end
	end

--check this page to see if it is in one of the namespaces that cs1 is not supposed to add to the error categories.
	if not is_set(no_tracking_cats) then				-- ignore if we are already not going to categorize this page
		if inArray (this_page.nsText, cfg.uncategorized_namespaces) then
			no_tracking_cats = "true";					-- set no_tracking_cats
		end
	end

-- check for extra |page=, |pages= or |at= parameters. 
	if is_set(Page) then
		if is_set(Pages) or is_set(At) then
			Page = Page .. " " .. seterror('extra_pages');	-- add error message
			Pages = '';										-- unset the others
			At = '';
		end
	elseif is_set(Pages) then
		if is_set(At) then
			Pages = Pages .. " " .. seterror('extra_pages');	-- add error messages
			At = '';											-- unset
		end
	end	

-- both |publication-place= and |place= (|location=) allowed if different
	if not is_set(PublicationPlace) and is_set(Place) then
		PublicationPlace = Place;							-- promote |place= (|location=) to |publication-place
	end
	
	if PublicationPlace == Place then Place = ''; end		-- don't need both if they are the same
	
--[[
Parameter remapping for cite encyclopedia:
When the citation has these parameters:
	|encyclopedia and |title then map |title to |article and |encyclopedia to |title
	|encyclopedia and |article then map |encyclopedia to |title
	|encyclopedia then map |encyclopedia to |title

	|trans_title maps to |trans_chapter when |title is re-mapped

All other combinations of |encyclopedia, |title, and |article are not modified
]]
	if ( config.CitationClass == "encyclopaedia" ) then
		if is_set(Periodical) then					-- Periodical is set when |encyclopedia is set
			if is_set(Title) then
				if not is_set(Chapter) then
					Chapter = Title;				-- |encyclopedia and |title are set so map |title to |article and |encyclopedia to |title
					TransChapter = TransTitle;
					Title = Periodical;
					Periodical = '';				-- redundant so unset
					TransTitle = '';				-- redundant so unset
				end
			else									-- |title not set
				Title = Periodical;					-- |encyclopedia set and |article set or not set so map |encyclopedia to |title
				Periodical = '';					-- redundant so unset
			end
		end
	end

--special cases for citation.
	if (config.CitationClass == "citation") then		-- for citation templates
		if not is_set (Ref) then						-- if |ref= is not set
			Ref = "harv";								-- set default |ref=harv
		end
		if not is_set (sepc) then						-- if |separator= is not set
			sepc = ',';									-- set citation separator to its default (comma)
		end
	else												-- not a citation template
		if not is_set (sepc) then						-- if |separator= has not been set
			sepc = '.';									-- set cite xxx separator to its default (period)
		end
	end

-- check for special case where |separator=none
	if 'none' == sepc:lower() then						-- if |separator=none
		sepc = '';										-- then set it to an empty string
	end

-- Special case for cite techreport.
	if (config.CitationClass == "techreport") then	-- special case for cite techreport
		if is_set(Issue) then						-- cite techreport uses 'number', which other citations aliase to 'issue'
			if not is_set(ID) then					-- can we use ID for the "number"?
				ID = Issue;							-- yes, use it
				Issue = "";							-- unset Issue so that "number" isn't duplicated in the rendered citation or COinS metadata
			else									-- can't use ID so emit error message
				ID = ID .. " " .. seterror('redundant_parameters', '<code>&#124;id=</code> and <code>&#124;number=</code>');
			end
		end	
	end

-- special case for cite interview
	if (config.CitationClass == "interview") then
		if is_set(Program) then
			ID = ' ' .. Program;
		end
		if is_set(Callsign) then
			if is_set(ID) then
				ID = ID .. sepc .. ' ' .. Callsign;
			else
				ID = ' ' .. Callsign;
			end
		end
		if is_set(City) then
			if is_set(ID) then
				ID = ID .. sepc .. ' ' .. City;
			else
				ID = ' ' .. City;
			end
		end

		if is_set(Interviewer) then
			if is_set(TitleType) then
				Others = ' ' .. TitleType .. ' with ' .. Interviewer;
				TitleType = '';
			else
				Others = ' ' .. 'Interview with ' .. Interviewer;
			end
			if is_set(Cointerviewers) then
				Others = Others .. sepc .. ' ' .. Cointerviewers;
			end
		else
			Others = '(Interview)';
		end
	end

--Account for the oddity that is {{cite journal}} with |pmc= set and |url= not set
	if config.CitationClass == "journal" and not is_set(URL) and is_set(ID_list['PMC']) then
		if not is_embargoed(Embargo) then
			URL=cfg.id_handlers['PMC'].prefix .. ID_list['PMC'];	-- set url to be the same as the PMC external link if not embargoed
			URLorigin = cfg.id_handlers['PMC'].parameters[1];		-- set URLorigin to parameter name for use in error message if citation is missing a |title=
		end
	end

-- Account for the oddity that is {{cite conference}}, before generation of COinS data.
--TODO: if this is only for {{cite conference}}, shouldn't we be checking? (if config.CitationClass=='conference' then ...)
	if is_set(BookTitle) then
		Chapter = Title;
		ChapterLink = TitleLink;
		TransChapter = TransTitle;
		Title = BookTitle;
		TitleLink = '';
		TransTitle = '';
	end

-- Account for the oddity that is {{cite episode}}, before generation of COinS data.
--[[	-- {{cite episode}} is not currently supported by this module
	if config.CitationClass == "episode" then
		local AirDate = A['AirDate'];
		local SeriesLink = A['SeriesLink'];
		local Season = A['Season'];
		local SeriesNumber = A['SeriesNumber'];
		local Network = A['Network'];
		local Station = A['Station'];
		local s, n = {}, {};
		local Sep = (first_set(A["SeriesSeparator"], A["Separator"]) or "") .. " ";
		
		if is_set(Issue) then table.insert(s, cfg.messages["episode"] .. " " .. Issue); Issue = ''; end
		if is_set(Season) then table.insert(s, cfg.messages["season"] .. " " .. Season); end
		if is_set(SeriesNumber) then table.insert(s, cfg.messages["series"] .. " " .. SeriesNumber); end
		if is_set(Network) then table.insert(n, Network); end
		if is_set(Station) then table.insert(n, Station); end
		
		Date = Date or AirDate;
		Chapter = Title;
		ChapterLink = TitleLink;
		TransChapter = TransTitle;
		Title = Series;
		TitleLink = SeriesLink;
		TransTitle = '';
		
		Series = table.concat(s, Sep);
		ID = table.concat(n, Sep);
	end
-- end of {{cite episode}} stuff]]

-- legacy: promote concatenation of |day=, |month=, and |year= to Date if Date not set; or, promote PublicationDate to Date if neither Date nor Year are set.
	if not is_set(Date) then
		Date = Year;						-- promote Year to Date
		Year = nil;							-- make nil so Year as empty string isn't used for CITEREF
		if is_set(Date) then
			local Month = A['Month'];
			if is_set(Month) then
				Date = Month .. " " .. Date;
				local Day = A['Day']
				if is_set(Day) then Date = Day .. " " .. Date end
			end
		elseif is_set(PublicationDate) then	-- use PublicationDate when |date= and |year= are not set
			Date = PublicationDate;			-- promote PublicationDate to Date
			PublicationDate = '';			-- unset, no longer needed
		end
	end

	if PublicationDate == Date then PublicationDate = ''; end	-- if PublicationDate is same as Date, don't display in rendered citation


--[[
Go test all of the date-holding parameters for valid MOS:DATE format and make sure that dates are real dates. This must be done before we do COinS because here is where
we get the date used in the metadata.

Date validation supporting code is in Module:Citation/CS1/Date_validation
]]
	anchor_year, COinS_date, error_message = dates({['accessdate']=AccessDate, ['airdate']=AirDate, ['archivedate']=ArchiveDate, ['date']=Date, ['doi_brokendate']=DoiBroken,
		['embargo']=Embargo, ['laydate']=LayDate, ['publicationdate']=PublicationDate, ['year']=Year});
	if is_set(error_message) then
		table.insert( z.message_tail, { seterror( 'bad_date', {error_message}, true ) } );	-- add this error message
	end

-- At this point fields may be nil if they weren't specified in the template use.  We can use that fact.

	-- COinS metadata (see <http://ocoins.info/>) for
	-- automated parsing of citation information.
	-- this is the function call to COinS()
	local OCinSoutput = COinS{
		['Periodical'] = Periodical,
		['Chapter'] = strip_apostrophe_markup (Chapter),						-- Chapter stripped of bold / italic wikimarkup
		['Title'] = make_coins_title (Title, ScriptTitle),		-- strip_apostrophe_markup (Title),							-- Title stripped of bold / italic wikimarkup
		['PublicationPlace'] = PublicationPlace,
		['Date'] = first_set(COinS_date, Date),		-- COinS_date has correctly formatted date if Date is valid; any reason to keep Date here?  Should we be including invalid dates in metadata?
		['Series'] = Series,
		['Volume'] = Volume,
		['Issue'] = Issue,
		['Pages'] = get_coins_pages (first_set(Page, Pages, At)),	-- pages stripped of external links
		['Edition'] = Edition,
		['PublisherName'] = PublisherName,
		['URL'] = first_set( URL, ChapterURL ),
		['Authors'] = a,
		['ID_list'] = ID_list,
		['RawPage'] = this_page.prefixedText,
	};
--[[Why is this here?  Why are we mapping Title to Chapter when Periodical is set?
	if is_set(Periodical) and not is_set(Chapter) and is_set(Title) then
		Chapter = Title;
		ChapterLink = TitleLink;
		TransChapter = TransTitle;
		Title = '';
		TitleLink = '';
		TransTitle = '';
	end
]]
--[[ Hide unfinished cite newsgroup code so that long delayed update can take place
-- special case for cite newsgroup.  Do this after COinS because we are modifying Publishername and ID
	if 'newsgroup' == config.CitationClass then
		if is_set (PublisherName) then
			PublisherName = '[Newsgroup]:&nbsp;' ..  externallink( 'news:' .. PublisherName, PublisherName );
		end
	end
]]


	-- Now perform various field substitutions.
	-- We also add leading spaces and surrounding markup and punctuation to the
	-- various parts of the citation, but only when they are non-nil.
	if not is_set(Authors) then
		local Maximum = tonumber( A['DisplayAuthors'] );
		
		-- Preserve old-style implicit et al.
		if not is_set(Maximum) and #a == 9 then 
			Maximum = 8;
			table.insert( z.message_tail, { seterror('implict_etal_author', {}, true ) } );
		elseif not is_set(Maximum) then
			Maximum = #a + 1;
		end
			
		local control = { 
			sep = A["AuthorSeparator"] .. " ",
			namesep = (first_set(A["AuthorNameSeparator"], A["NameSeparator"]) or "") .. " ",
			format = A["AuthorFormat"],
			maximum = Maximum,
			lastauthoramp = LastAuthorAmp,
			page_name = this_page.text				-- get current page name so that we don't wikilink to it via authorlinkn
		};
		
		-- If the coauthor field is also used, prevent ampersand and et al. formatting.
		if is_set(Coauthors) then
			control.lastauthoramp = nil;
			control.maximum = #a + 1;
		end
		
		Authors = listpeople(control, a) 
	end

	if not is_set(Authors) and is_set(Coauthors) then	-- coauthors aren't displayed if one of authors=, authorn=, or lastn= isn't specified
		table.insert( z.message_tail, { seterror('coauthors_missing_author', {}, true) } );	-- emit error message
	end

	local EditorCount
	if not is_set(Editors) then
		local Maximum = tonumber( A['DisplayEditors'] );
		-- Preserve old-style implicit et al.
		if not is_set(Maximum) and #e == 4 then 
			Maximum = 3;
			table.insert( z.message_tail, { seterror('implict_etal_editor', {}, true) } );
		elseif not is_set(Maximum) then
			Maximum = #e + 1;
		end

		local control = { 
			sep = A["EditorSeparator"] .. " ",
			namesep = (first_set(A["EditorNameSeparator"], A["NameSeparator"]) or "") .. " ",
			format = A['EditorFormat'],
			maximum = Maximum,
			lastauthoramp = LastAuthorAmp,
			page_name = this_page.text				-- get current page name so that we don't wikilink to it via authorlinkn
		};

		Editors, EditorCount = listpeople(control, e);
	else
		EditorCount = 1;
	end

	local Cartography = "";
	local Scale = "";
	if config.CitationClass == "map" then
		if not is_set( Authors ) and is_set( PublisherName ) then
			Authors = PublisherName;
			PublisherName = "";
		end
		Cartography = A['Cartography'];
		if is_set( Cartography ) then
			Cartography = sepc .. " " .. wrap( 'cartography', Cartography, use_lowercase );
		end		
		Scale = A['Scale'];
		if is_set( Scale ) then
			Scale = sepc .. " " .. Scale;
		end		
	end
	
	if  not is_set(URL) and
		not is_set(ChapterURL) and
		not is_set(ArchiveURL) and
		not is_set(ConferenceURL) and
		not is_set(TranscriptURL) then
		
		-- Test if cite web or cite podcast |url= is missing or empty 
		if inArray(config.CitationClass, {"web","podcast"}) then	
			table.insert( z.message_tail, { seterror( 'cite_web_url', {}, true ) } );
		end
		
		-- Test if accessdate is given without giving a URL
		if is_set(AccessDate) then
			table.insert( z.message_tail, { seterror( 'accessdate_missing_url', {}, true ) } );
			AccessDate = '';
		end
		
		-- Test if format is given without giving a URL
		if is_set(Format) then
			Format = Format .. seterror( 'format_missing_url' );
		end
	end
	
	-- Test if citation has no title
	if	not is_set(Title) and
		not is_set(Periodical) and
		not is_set(Conference) and
		not is_set(TransTitle) and
		not is_set(ScriptTitle) then
		table.insert( z.message_tail, { seterror( 'citation_missing_title', {}, true ) } );
	end
	
	Format = is_set(Format) and " (" .. Format .. ")" or "";
	
	local OriginalURL = URL
	DeadURL = DeadURL:lower();
	if is_set( ArchiveURL ) then
		if ( DeadURL ~= "no" ) then
			URL = ArchiveURL
			URLorigin = A:ORIGIN('ArchiveURL')
		end
	end
	
	-- Format chapter / article title
	if is_set(Chapter) and is_set(ChapterLink) then 
		Chapter = "[[" .. ChapterLink .. "|" .. Chapter .. "]]";
	end

	Chapter = kern_quotes (Chapter);				-- if necessary, separate chapter title's leading and trailing quote marks from Module provided quote marks
	Chapter = wrap( 'quoted-title', Chapter );
	TransChapter = wrap( 'trans-quoted-title', TransChapter );

	local TransError = ""
	if is_set(TransChapter) then
		if not is_set(Chapter) then
			TransError = " " .. seterror( 'trans_missing_chapter' );
		else
			TransChapter = " " .. TransChapter;
		end
	end
	
	Chapter = Chapter .. TransChapter;
	
	if is_set(Chapter) then
		if not is_set(ChapterLink) then
			if is_set(ChapterURL) then
				Chapter = externallink( ChapterURL, Chapter ) .. TransError;
				if not is_set(URL) then
					Chapter = Chapter .. Format;
					Format = "";
				end
			elseif is_set(URL) then 
				Chapter = externallink( URL, Chapter ) .. TransError .. Format;
				URL = "";
				Format = "";
			else
				Chapter = Chapter .. TransError;
			end			
		elseif is_set(ChapterURL) then
			Chapter = Chapter .. " " .. externallink( ChapterURL, nil, ChapterURLorigin ) .. 
				TransError;
		else
			Chapter = Chapter .. TransError;
		end
		Chapter = Chapter .. sepc .. " " -- with end-space
	elseif is_set(ChapterURL) then
		Chapter = " " .. externallink( ChapterURL, nil, ChapterURLorigin ) .. sepc .. " ";
	end		
	
	-- Format main title.
	if is_set(TitleLink) and is_set(Title) then
		Title = "[[" .. TitleLink .. "|" .. Title .. "]]"
	end

	if inArray(config.CitationClass, {"web","news","journal","pressrelease","conference","podcast"}) then
		Title = kern_quotes (Title);											-- if necessary, separate title's leading and trailing quote marks from Module provided quote marks
		Title = wrap( 'quoted-title', Title );
		Title = script_concatenate (Title, ScriptTitle);						-- <bdi> tags, lang atribute, categorization, etc; must be done after title is wrapped
		TransTitle = wrap( 'trans-quoted-title', TransTitle );
--		Chapter = '';								-- chapter not allowed - disabled because doing this here doesn't display error msg and promoted url is lost
	else
		Title = wrap( 'italic-title', Title );
		Title = script_concatenate (Title, ScriptTitle);						-- <bdi> tags, lang atribute, categorization, etc; must be done after title is wrapped
		TransTitle = wrap( 'trans-italic-title', TransTitle );
	end

	TransError = "";
	if is_set(TransTitle) then
		if is_set(Title) then
			TransTitle = " " .. TransTitle;
		else
			TransError = " " .. seterror( 'trans_missing_title' );
		end
	end
	
	Title = Title .. TransTitle;
	
	if is_set(Title) then
		if not is_set(TitleLink) and is_set(URL) then 
			Title = externallink( URL, Title ) .. TransError .. Format	   
			URL = "";
			Format = "";
		else
			Title = Title .. TransError;
		end
	end
	
	if is_set(Place) then
		Place = " " .. wrap( 'written', Place, use_lowercase ) .. sepc .. " ";
	end
	
	if is_set(Conference) then
		if is_set(ConferenceURL) then
			Conference = externallink( ConferenceURL, Conference );
		end
		Conference = sepc .. " " .. Conference
	elseif is_set(ConferenceURL) then
		Conference = sepc .. " " .. externallink( ConferenceURL, nil, ConferenceURLorigin );
	end
	
	if not is_set(Position) then
		local Minutes = A['Minutes'];
		if is_set(Minutes) then
			Position = " " .. Minutes .. " " .. cfg.messages['minutes'];
		else
			local Time = A['Time'];
			if is_set(Time) then
				local TimeCaption = A['TimeCaption']
				if not is_set(TimeCaption) then
					TimeCaption = cfg.messages['event'];
					if sepc ~= '.' then
						TimeCaption = TimeCaption:lower();
					end
				end
				Position = " " .. TimeCaption .. " " .. Time;
			end
		end
	else
		Position = " " .. Position;
		At = '';
	end
	
	if not is_set(Page) then
		if is_set(Pages) then
			if is_set(Periodical) and
				not inArray(config.CitationClass, {"encyclopaedia","web","book","news","podcast"}) then
				Pages = ": " .. Pages;
			elseif tonumber(Pages) ~= nil then
				Pages = sepc .." " .. PPrefix .. Pages;
			else
				Pages = sepc .." " .. PPPrefix .. Pages;
			end
		end
	else
		if is_set(Periodical) and
			not inArray(config.CitationClass, {"encyclopaedia","web","book","news","podcast"}) then
			Page = ": " .. Page;
		else
			Page = sepc .." " .. PPrefix .. Page;
		end
	end
	
	At = is_set(At) and (sepc .. " " .. At) or "";
	Position = is_set(Position) and (sepc .. " " .. Position) or "";
	if config.CitationClass == 'map' then
		local Section = A['Section'];
		local Inset = A['Inset'];
		if first_set( Pages, Page, At ) ~= nil or sepc ~= '.' then
			if is_set( Section ) then
				Section = ", " .. wrap( 'section', Section, true );
			end
			if is_set( Inset ) then
				Inset = ", " .. wrap( 'inset', Inset, true );
			end
		else
			if is_set( Section ) then
				Section = sepc .. " " .. wrap( 'section', Section, use_lowercase );
				if is_set( Inset ) then
					Inset = ", " .. wrap( 'inset', Inset, true );
				end
			elseif is_set( Inset ) then
				Inset = sepc .. " " .. wrap( 'inset', Inset, use_lowercase );
			end			
		end			
		At = At .. Section .. Inset;		
	end	

	if is_set (Language) then
		Language = language_parameter (Language, this_page.namespace);			-- format, categories (article namespace only), name from ISO639-1, etc
	else
		Language="";															-- language not specified so make sure this is an empty string;
	end

	Others = is_set(Others) and (sepc .. " " .. Others) or "";

-- handle type parameter for those CS1 citations that have default values

	if inArray(config.CitationClass, {"AV-media-notes", "DVD-notes", "podcast", "pressrelease", "techreport", "thesis"}) then
		TitleType = set_titletype (config.CitationClass, TitleType);
		if is_set(Degree) and "Thesis" == TitleType then	-- special case for cite thesis
			TitleType = Degree .. " thesis";
		end
	end

	if is_set(TitleType) then					-- if type parameter is specified
		TitleType = " (" .. TitleType .. ")";	-- display it in parentheses
	end

	TitleNote = is_set(TitleNote) and (sepc .. " " .. TitleNote) or "";
	Edition = is_set(Edition) and (" " .. wrap( 'edition', Edition )) or "";
	Issue = is_set(Issue) and (" (" .. Issue .. ")") or "";
	Series = is_set(Series) and (sepc .. " " .. Series) or "";
	OrigYear = is_set(OrigYear) and (" [" .. OrigYear .. "]") or "";
	Agency = is_set(Agency) and (sepc .. " " .. Agency) or "";

	if is_set(Volume) then
		if ( mw.ustring.len(Volume) > 4 )
		  then Volume = sepc .." " .. Volume;
		  else Volume = " <b>" .. hyphentodash(Volume) .. "</b>";
		end
	end

--[[ This code commented out while discussion continues until after week of 2014-03-23 live module update;
	if is_set(Volume) then
		if ( mw.ustring.len(Volume) > 4 )
		  then Volume = sepc .. " " .. Volume;
		  else
			  Volume = " <b>" .. hyphentodash(Volume) .. "</b>";
			  if is_set(Series) then Volume = sepc .. Volume;
			  end
		end
	end
]]	
	------------------------------------ totally unrelated data
	--[[ Loosely mimic {{subscription required}} template; Via parameter identifies a delivery source that is not the publisher; these sources often, but not always, exist
	behind a registration or paywall.  So here, we've chosen to decouple via from subscription (via has never been part of the registration required template).
	
	Subscription implies paywall; Registration does not.  If both are used in a citation, the subscription required link note is displayed. There are no error messages for this condition.
	]]
	if is_set(Via) then
		Via = " " .. wrap( 'via', Via );
	end

	if is_set(SubscriptionRequired) then
		SubscriptionRequired = sepc .. " " .. cfg.messages['subscription']; --here when 'via' parameter not used but 'subscription' is
	elseif is_set(RegistrationRequired) then
		SubscriptionRequired = sepc .. " " .. cfg.messages['registration']; --here when 'via' and 'subscription' parameters not used but 'registration' is
	end

	if is_set(AccessDate) then
		local retrv_text = " " .. cfg.messages['retrieved']
		if (sepc ~= ".") then retrv_text = retrv_text:lower() end
		AccessDate = '<span class="reference-accessdate">' .. sepc
			.. substitute( retrv_text, {AccessDate} ) .. '</span>'
	end
	
	if is_set(ID) then ID = sepc .." ".. ID; end
   	if "thesis" == config.CitationClass and is_set(Docket) then
		ID = sepc .." Docket ".. Docket .. ID;
	end

	
	ID_list = buildidlist( ID_list, {DoiBroken = DoiBroken, ASINTLD = ASINTLD, IgnoreISBN = IgnoreISBN, Embargo=Embargo} );

	if is_set(URL) then
		URL = " " .. externallink( URL, nil, URLorigin );
	end

	if is_set(Quote) then
		if Quote:sub(1,1) == '"' and Quote:sub(-1,-1) == '"' then
			Quote = Quote:sub(2,-2);
		end
		Quote = sepc .." " .. wrap( 'quoted-text', Quote ); 
		PostScript = "";							-- CS1 does not supply terminal punctuation when |quote= is set
	end
	
	local Archived
	if is_set(ArchiveURL) then
		if not is_set(ArchiveDate) then
			ArchiveDate = seterror('archive_missing_date');
		end
		if "no" == DeadURL then
			local arch_text = cfg.messages['archived'];
			if sepc ~= "." then arch_text = arch_text:lower() end
			Archived = sepc .. " " .. substitute( cfg.messages['archived-not-dead'],
				{ externallink( ArchiveURL, arch_text ), ArchiveDate } );
			if not is_set(OriginalURL) then
				Archived = Archived .. " " .. seterror('archive_missing_url');							   
			end
		elseif is_set(OriginalURL) then
			local arch_text = cfg.messages['archived-dead'];
			if sepc ~= "." then arch_text = arch_text:lower() end
			Archived = sepc .. " " .. substitute( arch_text,
				{ externallink( OriginalURL, cfg.messages['original'] ), ArchiveDate } );
		else
			local arch_text = cfg.messages['archived-missing'];
			if sepc ~= "." then arch_text = arch_text:lower() end
			Archived = sepc .. " " .. substitute( arch_text, 
				{ seterror('archive_missing_url'), ArchiveDate } );
		end
	else
		Archived = ""
	end
	
	local Lay
	if is_set(LayURL) then
		if is_set(LayDate) then LayDate = " (" .. LayDate .. ")" end
		if is_set(LaySource) then 
			LaySource = " &ndash; ''" .. safeforitalics(LaySource) .. "''";
		else
			LaySource = "";
		end
		if sepc == '.' then
			Lay = sepc .. " " .. externallink( LayURL, cfg.messages['lay summary'] ) .. LaySource .. LayDate
		else
			Lay = sepc .. " " .. externallink( LayURL, cfg.messages['lay summary']:lower() ) .. LaySource .. LayDate
		end			
	else
		Lay = "";
	end
	
	if is_set(Transcript) then
		if is_set(TranscriptURL) then Transcript = externallink( TranscriptURL, Transcript ); end
	elseif is_set(TranscriptURL) then
		Transcript = externallink( TranscriptURL, nil, TranscriptURLorigin );
	end
	
	local Publisher;
	if is_set(Periodical) and
		not inArray(config.CitationClass, {"encyclopaedia","web","pressrelease","podcast"}) then
		if is_set(PublisherName) then
			if is_set(PublicationPlace) then
				Publisher = PublicationPlace .. ": " .. PublisherName;
			else
				Publisher = PublisherName;  
			end
		elseif is_set(PublicationPlace) then
			Publisher= PublicationPlace;
		else 
			Publisher = "";
		end
		if is_set(PublicationDate) then
			if is_set(Publisher) then
				Publisher = Publisher .. ", " .. wrap( 'published', PublicationDate );
			else
				Publisher = PublicationDate;
			end
		end
		if is_set(Publisher) then
			Publisher = " (" .. Publisher .. ")";
		end
	else
		if is_set(PublicationDate) then
			PublicationDate = " (" .. wrap( 'published', PublicationDate ) .. ")";
		end
		if is_set(PublisherName) then
			if is_set(PublicationPlace) then
				Publisher = sepc .. " " .. PublicationPlace .. ": " .. PublisherName .. PublicationDate;
			else
				Publisher = sepc .. " " .. PublisherName .. PublicationDate;  
			end			
		elseif is_set(PublicationPlace) then 
			Publisher= sepc .. " " .. PublicationPlace .. PublicationDate;
		else 
			Publisher = PublicationDate;
		end
	end
	
	-- Several of the above rely upon detecting this as nil, so do it last.
	if is_set(Periodical) then
		if is_set(Title) or is_set(TitleNote) then 
			Periodical = sepc .. " " .. wrap( 'italic-title', Periodical ) 
		else 
			Periodical = wrap( 'italic-title', Periodical )
		end
	end

--[[
Handle the oddity that is cite speech.  This code overrides whatever may be the value assigned to TitleNote (through |department=) and forces it to be " (Speech)" so that
the annotation directly follows the |title= parameter value in the citation rather than the |event= parameter value (if provided).
]]
	if "speech" == config.CitationClass then				-- cite speech only
		TitleNote = " (Speech)";							-- annotate the citation
		if is_set (Periodical) then							-- if Periodical, perhaps because of an included |website= or |journal= parameter 
			if is_set (Conference) then						-- and if |event= is set
				Conference = Conference .. sepc .. " ";		-- then add appropriate punctuation to the end of the Conference variable before rendering
			end
		end
	end

	-- Piece all bits together at last.  Here, all should be non-nil.
	-- We build things this way because it is more efficient in LUA
	-- not to keep reassigning to the same string variable over and over.

	local tcommon
	if inArray(config.CitationClass, {"journal","citation"}) and is_set(Periodical) then
		if is_set(Others) then Others = Others .. sepc .. " " end
		tcommon = safejoin( {Others, Title, TitleNote, Conference, Periodical, Format, TitleType, Scale, Series, 
			Language, Cartography, Edition, Publisher, Agency, Volume, Issue}, sepc );
	else 
		tcommon = safejoin( {Title, TitleNote, Conference, Periodical, Format, TitleType, Scale, Series, Language, 
			Volume, Issue, Others, Cartography, Edition, Publisher, Agency}, sepc );
	end
	
	if #ID_list > 0 then
		ID_list = safejoin( { sepc .. " ",  table.concat( ID_list, sepc .. " " ), ID }, sepc );
	else
		ID_list = ID;
	end
	
	local idcommon = safejoin( { ID_list, URL, Archived, AccessDate, Via, SubscriptionRequired, Lay, Quote }, sepc );
	local text;
	local pgtext = Position .. Page .. Pages .. At;
	
	if is_set(Authors) then
		if is_set(Coauthors) then
			Authors = Authors .. A['AuthorSeparator'] .. " " .. Coauthors
		end
		if is_set(Date) then
			Date = " ("..Date..")" .. OrigYear .. sepc .. " "
		elseif string.sub(Authors,-1,-1) == sepc then
			Authors = Authors .. " "
		else
			Authors = Authors .. sepc .. " "
		end
		if is_set(Editors) then
			local in_text = " ";
			local post_text = "";
			if is_set(Chapter) then
				in_text = in_text .. cfg.messages['in'] .. " "
			else
				if EditorCount <= 1 then
					post_text = ", " .. cfg.messages['editor'];
				else
					post_text = ", " .. cfg.messages['editors'];
				end
			end 
			if (sepc ~= '.') then in_text = in_text:lower() end
			Editors = in_text .. Editors .. post_text;
			if (string.sub(Editors,-1,-1) == sepc)
				then Editors = Editors .. " "
				else Editors = Editors .. sepc .. " "
			end
		end
		text = safejoin( {Authors, Date, Chapter, Place, Editors, tcommon }, sepc );
		text = safejoin( {text, pgtext, idcommon}, sepc );
	elseif is_set(Editors) then
		if is_set(Date) then
			if EditorCount <= 1 then
				Editors = Editors .. ", " .. cfg.messages['editor'];
			else
				Editors = Editors .. ", " .. cfg.messages['editors'];
			end
			Date = " (" .. Date ..")" .. OrigYear .. sepc .. " "
		else
			if EditorCount <= 1 then
				Editors = Editors .. " (" .. cfg.messages['editor'] .. ")" .. sepc .. " "
			else
				Editors = Editors .. " (" .. cfg.messages['editors'] .. ")" .. sepc .. " "
			end
		end
		text = safejoin( {Editors, Date, Chapter, Place, tcommon}, sepc );
		text = safejoin( {text, pgtext, idcommon}, sepc );
	else
		if is_set(Date) then
			if ( string.sub(tcommon,-1,-1) ~= sepc )
			  then Date = sepc .." " .. Date .. OrigYear
			  else Date = " " .. Date .. OrigYear
			end
		end
		if config.CitationClass=="journal" and is_set(Periodical) then
			text = safejoin( {Chapter, Place, tcommon}, sepc );
			text = safejoin( {text, pgtext, Date, idcommon}, sepc );
		else
			text = safejoin( {Chapter, Place, tcommon, Date}, sepc );
			text = safejoin( {text, pgtext, idcommon}, sepc );
		end
	end
	
	if is_set(PostScript) and PostScript ~= sepc then
		text = safejoin( {text, sepc}, sepc );  --Deals with italics, spaces, etc.
		text = text:sub(1,-sepc:len()-1);
--		text = text:sub(1,-2);	--Remove final separator (assumes that sepc is only one character)
	end	
	
	text = safejoin( {text, PostScript}, sepc );

	-- Now enclose the whole thing in a <span/> element
	local options = {};
	
	if is_set(config.CitationClass) and config.CitationClass ~= "citation" then
		options.class = "citation " .. config.CitationClass;
	else
		options.class = "citation";
	end
	
	if is_set(Ref) and Ref:lower() ~= "none" then
		local id = Ref
		if ( "harv" == Ref ) then
			local names = {} --table of last names & year
			if #a > 0 then
				for i,v in ipairs(a) do 
					names[i] = v.last 
					if i == 4 then break end
				end
			elseif #e > 0 then
				for i,v in ipairs(e) do 
					names[i] = v.last 
					if i == 4 then break end				
				end
			end
			names[ #names + 1 ] = first_set(Year, anchor_year);	-- Year first for legacy citations
			id = anchorid(names)
		end
		options.id = id;
	end
	
	if string.len(text:gsub("<span[^>/]*>.-</span>", ""):gsub("%b<>","")) <= 2 then
		z.error_categories = {};
		text = seterror('empty_citation');
		z.message_tail = {};
	end
	
	if is_set(options.id) then 
		text = '<span id="' .. mw.uri.anchorEncode(options.id) ..'" class="' .. mw.text.nowiki(options.class) .. '">' .. text .. "</span>";
	else
		text = '<span class="' .. mw.text.nowiki(options.class) .. '">' .. text .. "</span>";
	end		

	local empty_span = '<span style="display:none;">&nbsp;</span>';
	
	-- Note: Using display: none on then COinS span breaks some clients.
	local OCinS = '<span title="' .. OCinSoutput .. '" class="Z3988">' .. empty_span .. '</span>';
	text = text .. OCinS;
	
	if #z.message_tail ~= 0 then
		text = text .. " ";
		for i,v in ipairs( z.message_tail ) do
			if is_set(v[1]) then
				if i == #z.message_tail then
					text = text .. errorcomment( v[1], v[2] );
				else
					text = text .. errorcomment( v[1] .. "; ", v[2] );
				end
			end
		end
	end
	
	no_tracking_cats = no_tracking_cats:lower();
	if inArray(no_tracking_cats, {"", "no", "false", "n"}) then
		for _, v in ipairs( z.error_categories ) do
			text = text .. '[[Category:' .. v ..']]';
		end
		for _, v in ipairs( z.maintenance_cats ) do								-- append maintenance categories
			text = text .. '[[Category:' .. v ..']]';
		end
		for _, v in ipairs( z.properties_cats ) do								-- append maintenance categories
			text = text .. '[[Category:' .. v ..']]';
		end
	end
	
	return text
end

-- This is used by templates such as {{cite book}} to create the actual citation text.
function z.citation(frame)
	local pframe = frame:getParent()
	
	if nil ~= string.find( frame:getTitle(), 'sandbox', 1, true ) then				-- did the {{#invoke:}} use sandbox version?
		cfg = mw.loadData( 'Module:Citation/CS1/Configuration/sandbox' );	-- load sandbox versions of Configuration and Whitelist and ...
		whitelist = mw.loadData( 'Module:Citation/CS1/Whitelist/sandbox' );
		dates = require('Module:Citation/CS1/Date_validation/sandbox').dates	-- ... sandbox version of date validation code
	else																	-- otherwise
		cfg = mw.loadData( 'Module:Citation/CS1/Configuration' );			-- load live versions of Configuration and Whitelist and ...
		whitelist = mw.loadData( 'Module:Citation/CS1/Whitelist' );
		dates = require('Module:Citation/CS1/Date_validation').dates		-- ... live version of date validation code
	end
	
	local args = {};
	local suggestions = {};
	local error_text, error_state;

	local config = {};
	for k, v in pairs( frame.args ) do
		config[k] = v;
		args[k] = v;	   
	end	

	for k, v in pairs( pframe.args ) do
		if v ~= '' then
			if not validate( k ) then			
				error_text = "";
				if type( k ) ~= 'string' then
					-- Exclude empty numbered parameters
					if v:match("%S+") ~= nil then
						error_text, error_state = seterror( 'text_ignored', {v}, true );
					end
				elseif validate( k:lower() ) then 
					error_text, error_state = seterror( 'parameter_ignored_suggest', {k, k:lower()}, true );
				else
					if #suggestions == 0 then
						suggestions = mw.loadData( 'Module:Citation/CS1/Suggestions' );
					end
					if suggestions[ k:lower() ] ~= nil then
						error_text, error_state = seterror( 'parameter_ignored_suggest', {k, suggestions[ k:lower() ]}, true );
					else
						error_text, error_state = seterror( 'parameter_ignored', {k}, true );
					end
				end				  
				if error_text ~= '' then
					table.insert( z.message_tail, {error_text, error_state} );
				end				
			end
			args[k] = v;
		elseif args[k] ~= nil or (k == 'postscript') then
			args[k] = v;
		end		
	end	
	
	return citation0( config, args)
end

return z