Xem mã nguồn của Mô đun:Citation/CS1


require('Module:No globals');

--[[--------------------------< F O R W A R D   D E C L A R A T I O N S >--------------------------------------
each of these counts against the Lua upvalue limit
]]

local validation;																-- functions in Module:Citation/CS1/Date_validation

local utilities;																-- functions in Module:Citation/CS1/Utilities
local z ={};																	-- table of tables in Module:Citation/CS1/Utilities

local identifiers;																-- functions and tables in Module:Citation/CS1/Identifiers
local metadata;																	-- functions in Module:Citation/CS1/COinS
local cfg = {};																	-- table of configuration tables that are defined in Module:Citation/CS1/Configuration
local whitelist = {};															-- table of tables listing valid template parameter names; defined in Module:Citation/CS1/Whitelist
local contentLanguage = mw.getContentLanguage()

--[[------------------< P A G E   S C O P E   V A R I A B L E S >---------------
declare variables here that have page-wide scope that are not brought in from
other modules; that are created here and used here
]]
local added_deprecated_cat;														-- Boolean flag so that the category is added only once
local added_discouraged_cat;													-- Boolean flag so that the category is added only once
local added_vanc_errs;															-- Boolean flag so we only emit one Vancouver error / category
local Frame;																	-- holds the module's frame table

---Định dạng ngày tháng. Thay thế [[Bản mẫu:Ngày chuẩn]].
local function vi_formatdate(rawDate, dayPrefix)
	local formatStr = 'j "tháng" n "năm" Y'
	if dayPrefix then formatStr = '"ngày" ' .. formatStr end
	
	-- Năm
	if tonumber(rawDate) or mw.ustring.match(rawDate, "^[1-9]%d%d%d?%a?$") then
		return mw.text.trim(rawDate)
	-- Năm tháng
	elseif mw.ustring.match(rawDate, "^[Tt]háng %d%d?,? %d%d%d%d$") or
		mw.ustring.match(rawDate, "^[Tt]háng %d%d?,? năm %d%d%d%d$") or
		mw.ustring.match(rawDate, "^[Tt]háng %a+,? năm %d%d%d%d$") or
		mw.ustring.match(rawDate, "^%a+%.?,? %d%d%d%d$") or
		mw.ustring.match(rawDate, "^%d%d%d%d%-%d%d$") then
		rawDate = mw.ustring.gsub(rawDate, ",", "")
		formatStr = '"tháng" n "năm" Y'
	end
	
	local good, formattedDate = pcall(contentLanguage.formatDate, contentLanguage, formatStr, rawDate)
	if good then return formattedDate else return rawDate end
end
function z._vi_formatdate(frame)
	return vi_formatdate(frame.args[1], frame.args[2])
end

---Cho ra tên tiếng Việt của ngôn ngữ có mã được đưa vào. Nếu một tên ngôn ngữ
-- được đưa vào, tên đó được cho ra.
local function vi_formatlanguage(rawLanguage)
	local languageName = mw.language.fetchLanguageName(rawLanguage, contentLanguage:getCode())
	if not languageName or #languageName < 1 then return rawLanguage end
	
	return (mw.ustring.gsub(languageName, "^[Tt]iếng ", "tiếng ", 1))
end
function z._vi_formatlanguage(frame)
	return vi_formatlanguage(frame.args[1])
end

---Định dạng số ấn bản.
local function vi_formatedition(rawEdition)
	if tonumber(rawEdition) then return rawEdition end
	
	local num = mw.ustring.match(rawEdition, "(%d+)th") or
	mw.ustring.match(rawEdition, "(%d+)st") or
	mw.ustring.match(rawEdition, "(%d+)nd") or
	mw.ustring.match(rawEdition, "(%d+)rd")
	
	return num or ""
end
function z._vi_formatedition(frame)
	return vi_formatedition(frame.args[1])
end

--[[--------------------------< F I R S T _ S E T >------------------------------------------------------------

Locates and returns the first set value in a table of values where the order established in the table,
left-to-right (or top-to-bottom), is the order in which the values are evaluated.  Returns nil if none are set.

This version replaces the original 'for _, val in pairs do' and a similar version that used ipairs.  With the pairs
version the order of evaluation could not be guaranteed.  With the ipairs version, a nil value would terminate
the for-loop before it reached the actual end of the list.

]]

local function first_set (list, count)
	local i = 1;
	while i <= count do															-- loop through all items in list
		if utilities.is_set( list[i] ) then
			return list[i];														-- return the first set list member
		end
		i = i + 1;																-- point to next
	end
end


--[[--------------------------< A D D _ V A N C _ E R R O R >----------------------------------------------------

Adds a single Vancouver system error message to the template's output regardless of how many error actually exist.
To prevent duplication, added_vanc_errs is nil until an error message is emitted.

added_vanc_errs is a Boolean declared in page scope variables above

]]

local function add_vanc_error (source, position)
	if added_vanc_errs then return end
		
	added_vanc_errs = true;														-- note that we've added this category
	table.insert( z.message_tail, { utilities.set_message ( 'err_vancouver', {source, position}, true ) } );
end


--[[--------------------------< I S _ S C H E M E >------------------------------------------------------------

does this thing that purports to be a URI scheme seem to be a valid scheme?  The scheme is checked to see if it
is in agreement with http://tools.ietf.org/html/std66#section-3.1 which says:
	Scheme names consist of a sequence of characters beginning with a
   letter and followed by any combination of letters, digits, plus
   ("+"), period ("."), or hyphen ("-").

returns true if it does, else false

]]

local function is_scheme (scheme)
	return scheme and scheme:match ('^%a[%a%d%+%.%-]*:');						-- true if scheme is set and matches the pattern
end


--[=[-------------------------< I S _ D O M A I N _ N A M E >--------------------------------------------------

Does this thing that purports to be a domain name seem to be a valid domain name?

Syntax defined here: http://tools.ietf.org/html/rfc1034#section-3.5
BNF defined here: https://tools.ietf.org/html/rfc4234
Single character names are generally reserved; see https://tools.ietf.org/html/draft-ietf-dnsind-iana-dns-01#page-15;
	see also [[Single-letter second-level domain]]
list of TLDs: https://www.iana.org/domains/root/db

RFC 952 (modified by RFC 1123) requires the first and last character of a hostname to be a letter or a digit.  Between
the first and last characters the name may use letters, digits, and the hyphen.

Also allowed are IPv4 addresses. IPv6 not supported

domain is expected to be stripped of any path so that the last character in the last character of the TLD.  tld
is two or more alpha characters.  Any preceding '//' (from splitting a URL with a scheme) will be stripped
here.  Perhaps not necessary but retained in case it is necessary for IPv4 dot decimal.

There are several tests:
	the first character of the whole domain name including subdomains must be a letter or a digit
	internationalized domain name (ASCII characters with .xn-- ASCII Compatible Encoding (ACE) prefix xn-- in the TLD) see https://tools.ietf.org/html/rfc3490
	single-letter/digit second-level domains in the .org, .cash, and .today TLDs
	q, x, and z SL domains in the .com TLD
	i and q SL domains in the .net TLD
	single-letter SL domains in the ccTLDs (where the ccTLD is two letters)
	two-character SL domains in gTLDs (where the gTLD is two or more letters)
	three-plus-character SL domains in gTLDs (where the gTLD is two or more letters)
	IPv4 dot-decimal address format; TLD not allowed

returns true if domain appears to be a proper name and TLD or IPv4 address, else false

]=]

local function is_domain_name (domain)
	if not domain then
		return false;															-- if not set, abandon
	end
	
	domain = domain:gsub ('^//', '');											-- strip '//' from domain name if present; done here so we only have to do it once
	
	if not domain:match ('^[%w]') then											-- first character must be letter or digit
		return false;
	end

	if domain:match ('^%a+:') then												-- hack to detect things that look like s:Page:Title where Page: is namespace at Wikisource
		return false;
	end

	local patterns = {															-- patterns that look like URLs
		'%f[%w][%w][%w%-]+[%w]%.%a%a+$',										-- three or more character hostname.hostname or hostname.tld
		'%f[%w][%w][%w%-]+[%w]%.xn%-%-[%w]+$',									-- internationalized domain name with ACE prefix
		'%f[%a][qxz]%.com$',													-- assigned one character .com hostname (x.com times out 2015-12-10)
		'%f[%a][iq]%.net$',														-- assigned one character .net hostname (q.net registered but not active 2015-12-10)
		'%f[%w][%w]%.%a%a$',													-- one character hostname and ccTLD (2 chars)
		'%f[%w][%w][%w]%.%a%a+$',												-- two character hostname and TLD
		'^%d%d?%d?%.%d%d?%d?%.%d%d?%d?%.%d%d?%d?',								-- IPv4 address
		}

	for _, pattern in ipairs (patterns) do										-- loop through the patterns list
		if domain:match (pattern) then
			return true;														-- if a match then we think that this thing that purports to be a URL is a URL
		end
	end

	for _, d in ipairs ({'cash', 'company', 'today', 'org'}) do					-- look for single letter second level domain names for these top level domains
		if domain:match ('%f[%w][%w]%.' .. d) then
			return true
		end
	end
	return false;																-- no matches, we don't know what this thing is
end


--[[--------------------------< I S _ U R L >------------------------------------------------------------------

returns true if the scheme and domain parts of a URL appear to be a valid URL; else false.

This function is the last step in the validation process.  This function is separate because there are cases that
are not covered by split_url(), for example is_parameter_ext_wikilink() which is looking for bracketted external
wikilinks.

]]

local function is_url (scheme, domain)
	if utilities.is_set (scheme) then											-- if scheme is set check it and domain
		return is_scheme (scheme) and is_domain_name (domain);
	else
		return is_domain_name (domain);											-- scheme not set when URL is protocol-relative
	end
end


--[[--------------------------< S P L I T _ U R L >------------------------------------------------------------

Split a URL into a scheme, authority indicator, and domain.

First remove Fully Qualified Domain Name terminator (a dot following TLD) (if any) and any path(/), query(?) or fragment(#).

If protocol-relative URL, return nil scheme and domain else return nil for both scheme and domain.

When not protocol-relative, get scheme, authority indicator, and domain.  If there is an authority indicator (one
or more '/' characters immediately following the scheme's colon), make sure that there are only 2.

Any URL that does not have news: scheme must have authority indicator (//).  TODO: are there other common schemes
like news: that don't use authority indicator?

Strip off any port and path;

]]

local function split_url (url_str)
	local scheme, authority, domain;
	
	url_str = url_str:gsub ('([%a%d])%.?[/%?#].*$', '%1');						-- strip FQDN terminator and path(/), query(?), fragment (#) (the capture prevents false replacement of '//')

	if url_str:match ('^//%S*') then											-- if there is what appears to be a protocol-relative URL
		domain = url_str:match ('^//(%S*)')
	elseif url_str:match ('%S-:/*%S+') then										-- if there is what appears to be a scheme, optional authority indicator, and domain name
		scheme, authority, domain = url_str:match ('(%S-:)(/*)(%S+)');			-- extract the scheme, authority indicator, and domain portions
		if utilities.is_set (authority) then
			authority = authority:gsub ('//', '', 1);							-- replace place 1 pair of '/' with nothing;
			if utilities.is_set(authority) then									-- if anything left (1 or 3+ '/' where authority should be) then
				return scheme;													-- return scheme only making domain nil which will cause an error message
			end
		else
			if not scheme:match ('^news:') then									-- except for news:..., MediaWiki won't link URLs that do not have authority indicator; TODO: a better way to do this test?
				return scheme;													-- return scheme only making domain nil which will cause an error message
			end
		end
		domain = domain:gsub ('(%a):%d+', '%1');								-- strip port number if present
	end
	
	return scheme, domain;
end


--[[--------------------------< L I N K _ P A R A M _ O K >---------------------------------------------------

checks the content of |title-link=, |series-link=, |author-link=, etc. for properly formatted content: no wikilinks, no URLs

Link parameters are to hold the title of a Wikipedia article, so none of the WP:TITLESPECIALCHARACTERS are allowed:
	# < > [ ] | { } _
except the underscore which is used as a space in wiki URLs and # which is used for section links

returns false when the value contains any of these characters.

When there are no illegal characters, this function returns TRUE if value DOES NOT appear to be a valid URL (the
|<param>-link= parameter is ok); else false when value appears to be a valid URL (the |<param>-link= parameter is NOT ok).

]]

local function link_param_ok (value)
	local scheme, domain;
	if value:find ('[<>%[%]|{}]') then											-- if any prohibited characters
		return false;
	end

	scheme, domain = split_url (value);											-- get scheme or nil and domain or nil from URL; 
	return not is_url (scheme, domain);											-- return true if value DOES NOT appear to be a valid URL
end


--[[--------------------------< L I N K _ T I T L E _ O K >---------------------------------------------------

Use link_param_ok() to validate |<param>-link= value and its matching |<title>= value.

|<title>= may be wiki-linked but not when |<param>-link= has a value.  This function emits an error message when
that condition exists

check <link> for inter-language interwiki-link prefix.  prefix must be a MediaWiki-recognized language
code and must begin with a colon.

]]

local function link_title_ok (link, lorig, title, torig)
local orig;
	if utilities.is_set (link) then 											-- don't bother if <param>-link doesn't have a value
		if not link_param_ok (link) then										-- check |<param>-link= markup
			orig = lorig;														-- identify the failing link parameter
		elseif title:find ('%[%[') then											-- check |title= for wikilink markup
			orig = torig;														-- identify the failing |title= parameter
		elseif link:match ('^%a+:') then										-- if the link is what looks like an interwiki
			local prefix = link:match ('^(%a+):'):lower();						-- get the interwiki prefix

			if cfg.inter_wiki_map[prefix] then									-- if prefix is in the map, must have preceding colon
				orig = lorig;													-- flag as error
			end
		end
	end

	if utilities.is_set (orig) then
		link = '';																-- unset
		table.insert( z.message_tail, { utilities.set_message ( 'err_bad_paramlink', orig)});	-- URL or wikilink in |title= with |title-link=;
	end
	
	return link;																-- link if ok, empty string else
end


--[[--------------------------< C H E C K _ U R L >------------------------------------------------------------

Determines whether a URL string appears to be valid.

First we test for space characters.  If any are found, return false.  Then split the URL into scheme and domain
portions, or for protocol-relative (//example.com) URLs, just the domain.  Use is_url() to validate the two
portions of the URL.  If both are valid, or for protocol-relative if domain is valid, return true, else false.

Because it is different from a standard URL, and because this module used external_link() to make external links
that work for standard and news: links, we validate newsgroup names here.  The specification for a newsgroup name
is at https://tools.ietf.org/html/rfc5536#section-3.1.4

]]

local function check_url( url_str )
	if nil == url_str:match ("^%S+$") then										-- if there are any spaces in |url=value it can't be a proper URL
		return false;
	end
	local scheme, domain;

	scheme, domain = split_url (url_str);										-- get scheme or nil and domain or nil from URL;
	
	if 'news:' == scheme then													-- special case for newsgroups
		return domain:match('^[%a%d%+%-_]+%.[%a%d%+%-_%.]*[%a%d%+%-_]$');
	end
	
	return is_url (scheme, domain);												-- return true if value appears to be a valid URL
end


--[=[-------------------------< I S _ P A R A M E T E R _ E X T _ W I K I L I N K >----------------------------

Return true if a parameter value has a string that begins and ends with square brackets [ and ] and the first
non-space characters following the opening bracket appear to be a URL.  The test will also find external wikilinks
that use protocol-relative URLs. Also finds bare URLs.

The frontier pattern prevents a match on interwiki-links which are similar to scheme:path URLs.  The tests that
find bracketed URLs are required because the parameters that call this test (currently |title=, |chapter=, |work=,
and |publisher=) may have wikilinks and there are articles or redirects like '//Hus' so, while uncommon, |title=[[//Hus]]
is possible as might be [[en://Hus]].

]=]

local function is_parameter_ext_wikilink (value)
local scheme, domain;

	if value:match ('%f[%[]%[%a%S*:%S+.*%]') then								-- if ext. wikilink with scheme and domain: [xxxx://yyyyy.zzz]
		scheme, domain = split_url (value:match ('%f[%[]%[(%a%S*:%S+).*%]'));
	elseif value:match ('%f[%[]%[//%S+.*%]') then								-- if protocol-relative ext. wikilink: [//yyyyy.zzz]
		scheme, domain = split_url (value:match ('%f[%[]%[(//%S+).*%]'));
	elseif value:match ('%a%S*:%S+') then										-- if bare URL with scheme; may have leading or trailing plain text
		scheme, domain = split_url (value:match ('(%a%S*:%S+)'));
	elseif value:match ('//%S+') then											-- if protocol-relative bare URL: //yyyyy.zzz; may have leading or trailing plain text
		scheme, domain = split_url (value:match ('(//%S+)'));					-- what is left should be the domain
	else
		return false;															-- didn't find anything that is obviously a URL
	end

	return is_url (scheme, domain);												-- return true if value appears to be a valid URL
end


--[[-------------------------< C H E C K _ F O R _ U R L >-----------------------------------------------------

loop through a list of parameters and their values.  Look at the value and if it has an external link, emit an error message.

]]

local function check_for_url (parameter_list)
local error_message = '';
	for k, v in pairs (parameter_list) do										-- for each parameter in the list
		if is_parameter_ext_wikilink (v) then									-- look at the value; if there is a URL add an error message
			if utilities.is_set(error_message) then								-- once we've added the first portion of the error message ...
				error_message = error_message .. ", ";							-- ... add a comma space separator
			end
			error_message = error_message .. "&#124;" .. k .. "=";				-- add the failed parameter
		end
	end
	if utilities.is_set (error_message) then									-- done looping, if there is an error message, display it
		table.insert( z.message_tail, { utilities.set_message ( 'err_param_has_ext_link', {error_message}, true ) } );
	end
end


--[[--------------------------< S A F E _ F O R _ U R L >------------------------------------------------------

Escape sequences for content that will be used for URL descriptions

]]

local function safe_for_url( str )
	if str:match( "%[%[.-%]%]" ) ~= nil then 
		table.insert( z.message_tail, { utilities.set_message ( 'err_wikilink_in_url', {}, true ) } );
	end
	
	return str:gsub( '[%[%]\n]', {	
		['['] = '&#91;',
		[']'] = '&#93;',
		['\n'] = ' ' } );
end


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

Format an external link with error checking

]]

local function external_link( URL, label, source, access)
	local error_str = "";
	local domain;
	local path;
	local base_url;

	if not utilities.is_set ( label ) then
		label = URL;
		if utilities.is_set ( source ) then
			error_str = utilities.set_message ( 'err_bare_url_missing_title', { utilities.wrap_style ('parameter', source) }, false, " " );
		else
			error( cfg.messages["bare_url_no_origin"] );
		end			
	end
	if not check_url( URL ) then
		error_str = utilities.set_message ( 'err_bad_url', {utilities.wrap_style ('parameter', source)}, false, " " ) .. error_str;
	end
	
	domain, path = URL:match ('^([/%.%-%+:%a%d]+)([/%?#].*)$');					-- split the URL into scheme plus domain and path
	if path then																-- if there is a path portion
		path = path:gsub ('[%[%]]', {['['] = '%5b', [']'] = '%5d'});			-- replace '[' and ']' with their percent-encoded values
		URL = table.concat ({domain, path});									-- and reassemble
	end

	base_url = table.concat({ "[", URL, " ", safe_for_url (label), "]" });		-- assemble a wiki-markup URL

	if utilities.is_set (access) then											-- access level (subscription, registration, limited)
		base_url = utilities.substitute (cfg.presentation['ext-link-access-signal'], {cfg.presentation[access].class, cfg.presentation[access].title, base_url});	-- add the appropriate icon
	end
	
	return table.concat ({base_url, error_str});
end


--[[--------------------------< D E P R E C A T E D _ P A R A M E T E R >--------------------------------------

Categorize and emit an error message when the citation contains one or more deprecated parameters.  The function includes the
offending parameter name to the error message.  Only one error message is emitted regardless of the number of deprecated
parameters in the citation.

added_deprecated_cat is a Boolean declared in page scope variables above

]]

local function deprecated_parameter(name)
	if not added_deprecated_cat then
		added_deprecated_cat = true;											-- note that we've added this category
		table.insert( z.message_tail, { utilities.set_message ( 'err_deprecated_params', {name}, true ) } );	-- add error message
	end
end


--[[--------------------------< D I S C O U R A G E D _ P A R A M E T E R >------------------------------------

Categorize and emit an maintenance message when the citation contains one or more discouraged parameters.  Only
one error message is emitted regardless of the number of discouraged parameters in the citation.

added_discouraged_cat is a Boolean declared in page scope variables above

]]

local function discouraged_parameter(name)
	if not added_discouraged_cat then
		added_discouraged_cat = true;											-- note that we've added this category
		table.insert( z.message_tail, { utilities.set_message ( 'maint_discouraged', {name}, true ) } );	-- add maint message
	end
end


--[=[-------------------------< K E R N _ Q U O T E S >--------------------------------------------------------

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)
Double single quotes (italic or bold wiki-markup) are not kerned.

Replaces Unicode quote marks in plain text or in the label portion of a [[L|D]] style wikilink with typewriter
quote marks regardless of the need for kerning.  Unicode quote marks are not replaced in simple [[D]] wikilinks.

Call this function for chapter titles, for website titles, etc.; not for book titles.

]=]

local function kern_quotes (str)
	local cap = '';
	local cap2 = '';
	local wl_type, label, link;

	wl_type, label, link = utilities.is_wikilink (str);							-- wl_type is: 0, no wl (text in label variable); 1, [[D]]; 2, [[L|D]]
	
	if 1 == wl_type then														-- [[D]] simple wikilink with or without quote marks
		if mw.ustring.match (str, '%[%[[\"“”\'‘’].+[\"“”\'‘’]%]%]') then		-- leading and trailing quote marks
			str = utilities.substitute (cfg.presentation['kern-wl-both'], str);
		elseif mw.ustring.match (str, '%[%[[\"“”\'‘’].+%]%]')	then			-- leading quote marks
			str = utilities.substitute (cfg.presentation['kern-wl-left'], str);
		elseif mw.ustring.match (str, '%[%[.+[\"“”\'‘’]%]%]') then				-- trailing quote marks
			str = utilities.substitute (cfg.presentation['kern-wl-right'], str);
		end

	else																		-- plain text or [[L|D]]; text in label variable
		label = mw.ustring.gsub (label, '[“”]', '\"');							-- replace “” (U+201C & U+201D) with " (typewriter double quote mark)
		label = mw.ustring.gsub (label, '[‘’]', '\'');							-- replace ‘’ (U+2018 & U+2019) with ' (typewriter single quote mark)

		cap, cap2 = mw.ustring.match (label, "^([\"\'])([^\'].+)");				-- match leading double or single quote but not doubled single quotes (italic markup)
		if utilities.is_set (cap) then
			label = utilities.substitute (cfg.presentation['kern-left'], {cap, cap2});
		end
	
		cap, cap2 = mw.ustring.match (label, "^(.+[^\'])([\"\'])$")				-- match trailing double or single quote but not doubled single quotes (italic markup)
		if utilities.is_set (cap) then
			label = utilities.substitute (cfg.presentation['kern-right'], {cap, cap2});
		end
		
		if 2 == wl_type then
			str = utilities.make_wikilink (link, label);						-- reassemble the wikilink
		else
			str = label;
		end
	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 ISO 639-1 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 ISO 639-1 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.

Supports |script-title=, |script-chapter=, |script-<periodical>=

]]

local function format_script_value (script_value, script_param)
	local lang='';																-- initialize to empty string
	local name;
	if script_value:match('^%l%l%l?%s*:') then									-- if first 3 or 4 non-space characters are script language prefix
		lang = script_value:match('^(%l%l%l?)%s*:%s*%S.*');						-- get the language prefix or nil if there is no script
		if not utilities.is_set (lang) then
			table.insert( z.message_tail, { utilities.set_message ( 'err_script_parameter', {script_param, 'missing title part'}, true ) } );		-- prefix without 'title'; add error message
			return '';															-- script_value was just the prefix so return empty string
		end
																				-- if we get this far we have prefix and script
		name = cfg.lang_code_remap[lang] or mw.language.fetchLanguageName( lang, cfg.this_wiki_code );	-- get language name so that we can use it to categorize
		if utilities.is_set (name) then											-- is prefix a proper ISO 639-1 language code?
			name = mw.ustring.gsub(name, '^[Tt]iếng ', '', 1);
			script_value = script_value:gsub ('^%l+%s*:%s*', '');				-- strip prefix from script
																				-- is prefix one of these language codes?
			if utilities.in_array (lang, cfg.script_lang_codes) then
				utilities.add_prop_cat ('script_with_name', {name, lang})
			else
				table.insert( z.message_tail, { utilities.set_message ( 'err_script_parameter', {script_param, 'unknown language code'}, true ) } );	-- unknown script-language; add error message
			end
			lang = ' lang="' .. lang .. '" ';									-- convert prefix into a lang attribute
		else
			table.insert( z.message_tail, { utilities.set_message ( 'err_script_parameter', {script_param, 'invalid language code'}, true ) } );		-- invalid language code; add error message
			lang = '';															-- invalid so set lang to empty string
		end
	else
		table.insert( z.message_tail, { utilities.set_message ( 'err_script_parameter', {script_param, 'missing prefix'}, true ) } );				-- no language code prefix; add error message
	end
	script_value = utilities.substitute (cfg.presentation['bdi'], {lang, script_value});	-- isolate in case script is RTL

	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.
]]

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


--[[--------------------------< W R A P _ M S G >--------------------------------------------------------------

Applies additional message text to various parameter values. Supplied string is wrapped using a message_list
configuration taking one argument.  Supports lower case text for {{citation}} templates.  Additional text taken
from citation_config.messages - the reason this function is similar to but separate from wrap_style().

]]

local function wrap_msg (key, str, lower)
	if not utilities.is_set ( str ) then
		return "";
	end
	if true == lower then
		local msg;
		msg = cfg.messages[key]:lower();										-- set the message to lower case before 
		return utilities.substitute ( msg, str );								-- including template text
	else
		return utilities.substitute ( cfg.messages[key], str );
	end		
end


--[[----------------< W I K I S O U R C E _ U R L _ M A K E >-------------------

Makes a Wikisource URL from Wikisource interwiki-link.  Returns the URL and appropriate
label; nil else.

str is the value assigned to |chapter= (or aliases) or |title= or |title-link=

]]

local function wikisource_url_make (str)
	local wl_type, D, L;
	local ws_url, ws_label;
	local wikisource_prefix = table.concat ({'https://', cfg.this_wiki_code, '.wikisource.org/wiki/'});

	wl_type, D, L = utilities.is_wikilink (str);								-- wl_type is 0 (not a wikilink), 1 (simple wikilink), 2 (complex wikilink)

	if 0 == wl_type then														-- not a wikilink; might be from |title-link=
		str = D:match ('^[Ww]ikisource:(.+)') or D:match ('^[Ss]:(.+)');		-- article title from interwiki link with long-form or short-form namespace
		if utilities.is_set (str) then
			ws_url = table.concat ({											-- build a Wikisource URL
				wikisource_prefix,												-- prefix
				str,															-- article title
				});
			ws_label = str;														-- label for the URL
		end
	elseif 1 == wl_type then													-- simple wikilink: [[Wikisource:ws article]]
		str = D:match ('^[Ww]ikisource:(.+)') or D:match ('^[Ss]:(.+)');		-- article title from interwiki link with long-form or short-form namespace
		if utilities.is_set (str) then
			ws_url = table.concat ({											-- build a Wikisource URL
				wikisource_prefix,												-- prefix
				str,															-- article title
				});
			ws_label = str;														-- label for the URL
		end
	elseif 2 == wl_type then													-- non-so-simple wikilink: [[Wikisource:ws article|displayed text]] ([[L|D]])
		str = L:match ('^[Ww]ikisource:(.+)') or L:match ('^[Ss]:(.+)');		-- article title from interwiki link with long-form or short-form namespace
		if utilities.is_set (str) then
			ws_label = D;														-- get ws article name from display portion of interwiki link
			ws_url = table.concat ({											-- build a Wikisource URL
				wikisource_prefix,												-- prefix
				str,															-- article title without namespace from link portion of wikilink
				});
		end
	end

	if ws_url then
		ws_url = mw.uri.encode (ws_url, 'WIKI');								-- make a usable URL
		ws_url = ws_url:gsub ('%%23', '#');										-- undo percent-encoding of fragment marker
	end

	return ws_url, ws_label, L or D;											-- return proper URL or nil and a label or nil
end


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

Format the three periodical parameters: |script-<periodical>=, |<periodical>=,
and |trans-<periodical>= into a single Periodical meta-parameter.

]]

local function format_periodical (script_periodical, script_periodical_source, periodical, trans_periodical)
	local periodical_error = '';

	if not utilities.is_set (periodical) then
		periodical = '';														-- to be safe for concatenation
	else
		periodical = utilities.wrap_style ('italic-title', periodical);			-- style 
	end

	periodical = script_concatenate (periodical, script_periodical, script_periodical_source);	-- <bdi> tags, lang attribute, categorization, etc.; must be done after title is wrapped

	if utilities.is_set (trans_periodical) then
		trans_periodical = utilities.wrap_style ('trans-italic-title', trans_periodical);
		if utilities.is_set (periodical) then
			periodical = periodical .. ' ' .. trans_periodical;
		else																	-- here when trans-periodical without periodical or script-periodical
			periodical = trans_periodical;
			periodical_error = ' ' .. utilities.set_message ('err_trans_missing_title', {'periodical'});
		end
	end

	return periodical .. periodical_error;
end


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

Format the four chapter parameters: |script-chapter=, |chapter=, |trans-chapter=,
and |chapter-url= into a single chapter meta- parameter (chapter_url_source used
for error messages).

]]

local function format_chapter_title (script_chapter, script_chapter_source, chapter, chapter_source, trans_chapter, trans_chapter_source, chapter_url, chapter_url_source, no_quotes, access)
	local chapter_error = '';

	local ws_url, ws_label, L = wikisource_url_make (chapter);					-- make a wikisource URL and label from a wikisource interwiki link
	if ws_url then
		ws_label = ws_label:gsub ('_', ' ');									-- replace underscore separators with space characters
		chapter = ws_label;
	end

	if not utilities.is_set (chapter) then
		chapter = '';															-- to be safe for concatenation
	else
		if false == no_quotes then
			chapter = kern_quotes (chapter);									-- if necessary, separate chapter title's leading and trailing quote marks from module provided quote marks
			chapter = utilities.wrap_style ('quoted-title', chapter);
		end
	end

	chapter = script_concatenate (chapter, script_chapter, script_chapter_source);	-- <bdi> tags, lang attribute, categorization, etc.; must be done after title is wrapped

	if utilities.is_set (chapter_url) then
		chapter = external_link (chapter_url, chapter, chapter_url_source, access);	-- adds bare_url_missing_title error if appropriate
	elseif ws_url then
		chapter = external_link (ws_url, chapter .. '&nbsp;', 'ws link in chapter');	-- adds bare_url_missing_title error if appropriate; space char to move icon away from chap text; TODO: better way to do this?
		chapter = utilities.substitute (cfg.presentation['interwiki-icon'], {cfg.presentation['class-wikisource'], L, chapter});				
	end

	if utilities.is_set (trans_chapter) then
		trans_chapter = utilities.wrap_style ('trans-quoted-title', trans_chapter);
		if utilities.is_set (chapter) then
			chapter = chapter .. ' ' .. trans_chapter;
		else																	-- here when trans_chapter without chapter or script-chapter
			chapter = trans_chapter;
			chapter_source = trans_chapter_source:match ('trans%-?(.+)');		-- when no chapter, get matching name from trans-<param>
			chapter_error = ' ' .. utilities.set_message ('err_trans_missing_title', {chapter_source});
		end
	end

	return chapter .. chapter_error;
end


--[[----------------< H A S _ I N V I S I B L E _ C H A R S >-------------------

This function searches a parameter's value for non-printable or invisible characters.
The search stops at the first match.

This function will detect the visible replacement character when it is part of the Wikisource.

Detects but ignores nowiki and math stripmarkers.  Also detects other named stripmarkers
(gallery, math, pre, ref) and identifies them with a slightly different error message.
See also coins_cleanup().

Output of this function is an error message that identifies the character or the
Unicode group, or the stripmarker that was detected along with its position (or,
for multi-byte characters, the position of its first byte) in the parameter value.

]]

local function has_invisible_chars (param, v)
	local position = '';														-- position of invisible char or starting position of stripmarker
	local capture;																-- used by stripmarker detection to hold name of the stripmarker
	local stripmarker;															-- boolean set true when a stripmarker is found

	capture = string.match (v, '[%w%p ]*');										-- test for values that are simple ASCII text and bypass other tests if true
	if capture == v then														-- if same there are no Unicode characters
		return;
	end

	for _, invisible_char in ipairs (cfg.invisible_chars) do
		local char_name = invisible_char[1];									-- the character or group name
		local pattern = invisible_char[2];										-- the pattern used to find it
		position, _, capture = mw.ustring.find (v, pattern);					-- see if the parameter value contains characters that match the pattern
		
		if position and (cfg.invisible_defs.zwj == capture) then				-- if we found a zero-width joiner character
			if mw.ustring.find (v, cfg.indic_script) then						-- it's ok if one of the Indic scripts
				position = nil;													-- unset position
			elseif cfg.emoji[mw.ustring.codepoint (v, position+1)] then			-- is zwj followed by a character listed in emoji{}?
				position = nil;													-- unset position
			end
		end
		
		if position then
			if 'nowiki' == capture or 'math' == capture or						-- nowiki and math stripmarkers (not an error condition)
				('templatestyles' == capture and utilities.in_array (param, {'id', 'quote'})) then	-- templatestyles stripmarker allowed in these parameters
					stripmarker = true;											-- set a flag
			elseif true == stripmarker and cfg.invisible_defs.del == capture then	-- because stripmakers begin and end with the delete char, assume that we've found one end of a stripmarker
				position = nil;													-- unset
			else
				local err_msg;
				if capture and not (cfg.invisible_defs.del == capture or cfg.invisible_defs.zwj == capture) then
					err_msg = capture .. ' ' .. char_name;
				else
					err_msg = char_name .. ' ' .. 'character';
				end

				table.insert (z.message_tail, {utilities.set_message ('err_invisible_char', {err_msg, utilities.wrap_style ('parameter', param), position}, true)});	-- add error message
				return;															-- and done with this parameter
			end
		end
	end
end


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

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.

]]

local 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] = utilities.select_one ( args, list, 'err_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'] .. ': ' .. k);
			end
			
			-- Empty strings, not nil;
			if v == nil then
				v = '';
				origin[k] = '';
			end
			
			tbl = rawset( tbl, k, v );
			return v;
		end,
	});
end


--[[--------------------------< N O W R A P _ D A T E >-------------------------

When date is YYYY-MM-DD format wrap in nowrap span: <span ...>YYYY-MM-DD</span>.
When date is DD MMMM YYYY or is MMMM DD, YYYY then wrap in nowrap span:
<span ...>DD MMMM</span> YYYY or <span ...>MMMM DD,</span> YYYY

DOES NOT yet support MMMM YYYY or any of the date ranges.

]]

local function nowrap_date (date)
	local cap = '';
	local cap2 = '';

	if date:match("^%d%d%d%d%-%d%d%-%d%d$") then
		date = utilities.substitute (cfg.presentation['nowrap1'], date);
	
	elseif date:match("^%a+%s*%d%d?,%s+%d%d%d%d$") or date:match ("^%d%d?%s*%a+%s+%d%d%d%d$") then
		cap, cap2 = string.match (date, "^(.*)%s+(%d%d%d%d)$");
		date = utilities.substitute (cfg.presentation['nowrap2'], {cap, cap2});
	end
	
	return date;
end


--[[--------------------------< S E T _ T I T L E T Y P E >---------------------

This function sets default title types (equivalent to the citation including
|type=<default value>) for those templates that have defaults. Also handles the
special case where it is desirable to omit the title type from the rendered citation
(|type=none).

]]

local function set_titletype (cite_class, title_type)
	if utilities.is_set (title_type) then
		if 'none' == cfg.keywords_xlate[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

	return cfg.title_types [cite_class] or '';									-- set template's default title type; else empty string for concatenation
end


--[[--------------------------< H Y P H E N _ T O _ D A S H >--------------------------------------------------

Converts a hyphen to a dash under certain conditions.  The hyphen must separate
like items; unlike items are returned unmodified.  These forms are modified:
	letter - letter (A - B)
	digit - digit (4-5)
	digit separator digit - digit separator digit (4.1-4.5 or 4-1-4-5)
	letterdigit - letterdigit (A1-A5) (an optional separator between letter and
		digit is supported – a.1-a.5 or a-1-a-5)
	digitletter - digitletter (5a - 5d) (an optional separator between letter and
		digit is supported – 5.a-5.d or 5-a-5-d)

any other forms are returned unmodified.

str may be a comma- or semicolon-separated list

]]

local function hyphen_to_dash( str )
	if not utilities.is_set (str) then
		return str;
	end

	local accept; -- Boolean

	str = str:gsub ('&[nm]dash;', {['&ndash;'] = '–', ['&mdash;'] = '—'});		-- replace &mdash; and &ndash; entities with their characters; semicolon mucks up the text.split
	str = str:gsub ('&#45;', '-'); -- replace HTML numeric entity with hyphen character

	str = str:gsub ('&nbsp;', ' '); -- replace &nbsp; entity with generic keyboard space character
	
	local out = {};
	local list = mw.text.split (str, '%s*[,;]%s*');								-- split str at comma or semicolon separators if there are any

	for _, item in ipairs (list) do												-- for each item in the list
		item, accept = utilities.has_accept_as_written (item);					-- remove accept-this-as-written markup when it wraps all of item
		if not accept and mw.ustring.match (item, '^%w*[%.%-]?%w+%s*[%-–—]%s*%w*[%.%-]?%w+$') then	-- if a hyphenated range or has endash or emdash separators
			if item:match ('^%a+[%.%-]?%d+%s*%-%s*%a+[%.%-]?%d+$') or			-- letterdigit hyphen letterdigit (optional separator between letter and digit)
				item:match ('^%d+[%.%-]?%a+%s*%-%s*%d+[%.%-]?%a+$') or			-- digitletter hyphen digitletter (optional separator between digit and letter)
				item:match ('^%d+[%.%-]%d+%s*%-%s*%d+[%.%-]%d+$') or			-- digit separator digit hyphen digit separator digit
				item:match ('^%d+%s*%-%s*%d+$') or								-- digit hyphen digit
				item:match ('^%a+%s*%-%s*%a+$') then							-- letter hyphen letter
					item = item:gsub ('(%w*[%.%-]?%w+)%s*%-%s*(%w*[%.%-]?%w+)', '%1–%2');	-- replace hyphen, remove extraneous space characters
			else
				item = mw.ustring.gsub (item, '%s*[–—]%s*', '–');				-- for endash or emdash separated ranges, replace em with en, remove extraneous whitespace
			end
		end
		table.insert (out, item);												-- add the (possibly modified) item to the output table
	end

	local temp_str = '';														-- concatenate the output table into a comma separated string
	temp_str, accept = utilities.has_accept_as_written (table.concat (out, ', ')); -- remove accept-this-as-written markup when it wraps all of concatenated out
	if accept then
		temp_str = utilities.has_accept_as_written (str);						-- when global markup removed, return original str; do it this way to suppress boolean second return value
		return temp_str;
	else
		return temp_str;														-- else, return assembled temp_str
	end
end


--[[--------------------------< S A F E _ J O I N >-----------------------------

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

]]

local function safe_join( tbl, duplicate_char )
	local f = {};																-- create a function table appropriate to type of 'duplicate character'
		if 1 == #duplicate_char then											-- for single byte ASCII characters use the string library functions
			f.gsub = string.gsub
			f.match = string.match
			f.sub = string.sub
		else																	-- for multi-byte characters use the ustring library functions
			f.gsub = mw.ustring.gsub
			f.match = mw.ustring.match
			f.sub = mw.ustring.sub
		end

	local str = '';																-- the output string
	local comp = '';															-- what does 'comp' mean?
	local end_chr = '';
	local trim;
	for _, value in ipairs( tbl ) do
		if value == nil then value = ''; end
		
		if str == '' then														-- if output string is empty
			str = value;														-- assign value to it (first time through the loop)
		elseif value ~= '' then
			if value:sub(1, 1) == '<' then										-- special case of values enclosed in spans and other markup.
				comp = value:gsub( "%b<>", "" );								-- remove HTML markup (<span>string</span> -> string)
			else
				comp = value;
			end
																				-- typically duplicate_char is sepc
			if f.sub(comp, 1, 1) == duplicate_char then							-- is first character same as duplicate_char? why test first character?
																				--   Because individual string segments often (always?) begin with terminal punct for the
																				--   preceding segment: 'First element' .. 'sepc next element' .. etc.?
				trim = false;
				end_chr = f.sub(str, -1, -1);									-- get the last character of the output string
				-- str = str .. "<HERE(enchr=" .. end_chr .. ")"				-- debug stuff?
				if end_chr == duplicate_char then								-- if same as separator
					str = f.sub(str, 1, -2);									-- remove it
				elseif end_chr == "'" then										-- if it might be wiki-markup
					if f.sub(str, -3, -1) == duplicate_char .. "''" then		-- if last three chars of str are sepc'' 
						str = f.sub(str, 1, -4) .. "''";						-- remove them and add back ''
					elseif  f.sub(str, -5, -1) == duplicate_char .. "]]''" then	-- if last five chars of str are sepc]]'' 
						trim = true;											-- why? why do this and next differently from previous?
					elseif f.sub(str, -4, -1) == duplicate_char .. "]''" then	-- if last four chars of str are sepc]'' 
						trim = true;											-- same question
					end
				elseif end_chr == "]" then										-- if it might be wiki-markup
					if f.sub(str, -3, -1) == duplicate_char .. "]]" then		-- if last three chars of str are sepc]] wikilink 
						trim = true;
					elseif f.sub(str, -3, -1) == duplicate_char .. '"]' then	-- if last three chars of str are sepc"] quoted external link 
						trim = true;
					elseif  f.sub(str, -2, -1) == duplicate_char .. "]" then	-- if last two chars of str are sepc] external link
						trim = true;
					elseif f.sub(str, -4, -1) == duplicate_char .. "'']" then	-- normal case when |url=something & |title=Title.
						trim = true;
					end
				elseif end_chr == " " then										-- if last char of output string is a space
					if f.sub(str, -2, -1) == duplicate_char .. " " then			-- if last two chars of str are <sepc><space>
						str = f.sub(str, 1, -3);								-- remove them both
					end
				end

				if trim then
					if value ~= comp then 										-- value does not equal comp when value contains HTML markup
						local dup2 = duplicate_char;
						if f.match(dup2, "%A" ) then dup2 = "%" .. dup2; end	-- if duplicate_char not a letter then escape it
						
						value = f.gsub(value, "(%b<>)" .. dup2, "%1", 1 )		-- remove duplicate_char if it follows HTML markup
					else
						value = f.sub(value, 2, -1 );							-- remove duplicate_char when it is first character
					end
				end
			end
			str = str .. value; 												-- add it to the output string
		end
	end
	return str;
end


--[[--------------------------< I S _ S U F F I X >-----------------------------

returns true is suffix is properly formed Jr, Sr, or ordinal in the range 1–9.
Puncutation not allowed.

]]

local function is_suffix (suffix)
	if utilities.in_array (suffix, {'Jr', 'Sr', 'Jnr', 'Snr', '1st', '2nd', '3rd'}) or suffix:match ('^%dth$') then
		return true;
	end
	return false;
end


--[[--------------------< I S _ G O O D _ V A N C _ N A M E >-------------------

For Vancouver style, author/editor names are supposed to be rendered in Latin
(read ASCII) characters.  When a name uses characters that contain diacritical
marks, those characters are to be converted to the corresponding Latin
character. When a name is written using a non-Latin alphabet or logogram, that
name is to be transliterated into Latin characters. The module doesn't do this
so editors may/must.

This test allows |first= and |last= names to contain any of the letters defined
in the four Unicode Latin character sets
	[http://www.unicode.org/charts/PDF/U0000.pdf C0 Controls and Basic Latin] 0041–005A, 0061–007A
	[http://www.unicode.org/charts/PDF/U0080.pdf C1 Controls and Latin-1 Supplement] 00C0–00D6, 00D8–00F6, 00F8–00FF
	[http://www.unicode.org/charts/PDF/U0100.pdf Latin Extended-A] 0100–017F
	[http://www.unicode.org/charts/PDF/U0180.pdf Latin Extended-B] 0180–01BF, 01C4–024F

|lastn= also allowed to contain hyphens, spaces, and apostrophes.
	(http://www.ncbi.nlm.nih.gov/books/NBK7271/box/A35029/)
|firstn= also allowed to contain hyphens, spaces, apostrophes, and periods

This original test:
	if nil == mw.ustring.find (last, "^[A-Za-zÀ-ÖØ-öø-ƿǄ-ɏ%-%s%']*$")
	or nil == mw.ustring.find (first, "^[A-Za-zÀ-ÖØ-öø-ƿǄ-ɏ%-%s%'%.]+[2-6%a]*$") then
was written outside of the code editor and pasted here because the code editor
gets confused between character insertion point and cursor position. The test has
been rewritten to use decimal character escape sequence for the individual bytes
of the Unicode characters so that it is not necessary to use an external editor
to maintain this code.

	\195\128-\195\150 – À-Ö (U+00C0–U+00D6 – C0 controls)
	\195\152-\195\182 – Ø-ö (U+00D8-U+00F6 – C0 controls)
	\195\184-\198\191 – ø-ƿ (U+00F8-U+01BF – C0 controls, Latin extended A & B)
	\199\132-\201\143 – Ǆ-ɏ (U+01C4-U+024F – Latin extended B)

]]

local function is_good_vanc_name (last, first, suffix, position)
	if not suffix then
		if first:find ('[,%s]') then											-- when there is a space or comma, might be first name/initials + generational suffix
			first = first:match ('(.-)[,%s]+');									-- get name/initials
			suffix = first:match ('[,%s]+(.+)$');								-- get generational suffix
		end
	end
	if utilities.is_set (suffix) then
		if not is_suffix (suffix) then
			add_vanc_error (cfg.err_msg_supl.suffix, position);
			return false;														-- not a name with an appropriate suffix
		end
	end
	if nil == mw.ustring.find (last, "^[A-Za-z\195\128-\195\150\195\152-\195\182\195\184-\198\191\199\132-\201\143%-%s%']*$") or
		nil == mw.ustring.find (first, "^[A-Za-z\195\128-\195\150\195\152-\195\182\195\184-\198\191\199\132-\201\143%-%s%'%.]*$") then
			add_vanc_error (cfg.err_msg_supl['non-Latin char'], position);
			return false;														-- not a string of Latin characters; Vancouver requires Romanization
	end;
	return true;
end


--[[--------------------------< R E D U C E _ T O _ I N I T I A L S >------------------------------------------

Attempts to convert names to initials in support of |name-list-style=vanc.  

Names in |firstn= may be separated by spaces or hyphens, or for initials, a period.
See http://www.ncbi.nlm.nih.gov/books/NBK7271/box/A35062/.

Vancouver style requires family rank designations (Jr, II, III, etc.) to be rendered
as Jr, 2nd, 3rd, etc.  See http://www.ncbi.nlm.nih.gov/books/NBK7271/box/A35085/.
This code only accepts and understands generational suffix in the Vancouver format
because Roman numerals look like, and can be mistaken for, initials.

This function uses ustring functions because firstname initials may be any of the
Unicode Latin characters accepted by is_good_vanc_name ().

]]

local function reduce_to_initials(first, position)
	local name, suffix = mw.ustring.match(first, "^(%u+) ([%dJS][%drndth]+)$");

	if not name then															-- if not initials and a suffix
		name = mw.ustring.match(first, "^(%u+)$");								-- is it just initials?
	end

	if name then																-- if first is initials with or without suffix
		if 3 > mw.ustring.len (name) then										-- if one or two initials
			if suffix then														-- if there is a suffix
				if is_suffix (suffix) then										-- is it legitimate?
					return first;												-- one or two initials and a valid suffix so nothing to do
				else
					add_vanc_error (cfg.err_msg_supl.suffix, position);			-- one or two initials with invalid suffix so error message
					return first;												-- and return first unmolested
				end
			else
				return first;													-- one or two initials without suffix; nothing to do
			end
		end
	end																			-- if here then name has 3 or more uppercase letters so treat them as a word

	local initials, names = {}, {};												-- tables to hold name parts and initials
	local i = 1;																-- counter for number of initials

	names = mw.text.split (first, '[%s,]+');									-- split into a table of names and possible suffix

	while names[i] do															-- loop through the table
		if 1 < i and names[i]:match ('[%dJS][%drndth]+%.?$') then				-- if not the first name, and looks like a suffix (may have trailing dot)
			names[i] = names[i]:gsub ('%.', '');								-- remove terminal dot if present
			if is_suffix (names[i]) then										-- if a legitimate suffix
				table.insert (initials, ' ' .. names[i]);						-- add a separator space, insert at end of initials table
				break;															-- and done because suffix must fall at the end of a name
			end																	-- no error message if not a suffix; possibly because of Romanization
		end
		if 3 > i then
			table.insert (initials, mw.ustring.sub(names[i], 1, 1));			-- insert the initial at end of initials table
		end
		i = i + 1;																-- bump the counter
	end
			
	return table.concat(initials)												-- Vancouver format does not include spaces.
end


--[[--------------------------< L I S T _ P E O P L E >--------------------------

Formats a list of people (authors, contributors, editors, interviewers, translators) 

names in the list will be linked when
	|<name>-link= has a value
	|<name>-mask- does NOT have a value; masked names are presumed to have been
		rendered previously so should have been linked there

when |<name>-mask=0, the associated name is not rendered

]]

local function list_people (control, people, etal)
	local sep;
	local namesep;
	local format = control.format;
	local maximum = control.maximum;
	local name_list = {};

	if 'vanc' == format then													-- Vancouver-like name styling?
		sep = cfg.presentation['sep_nl_vanc'];									-- name-list separator between names is a comma
		namesep = cfg.presentation['sep_name_vanc'];							-- last/first separator is a space
	else
		sep = cfg.presentation['sep_nl'];										-- name-list separator between names is a semicolon
		namesep = cfg.presentation['sep_name'];									-- last/first separator is <comma><space>
	end
	
	if sep:sub (-1, -1) ~= " " then sep = sep .. " " end
	if utilities.is_set (maximum) and maximum < 1 then return "", 0; end		-- returned 0 is for EditorCount; not used for other names
	
	for i, person in ipairs (people) do
		if utilities.is_set (person.last) then
			local mask = person.mask;
			local one;
			local sep_one = sep;

			if utilities.is_set (maximum) and i > maximum then
				etal = true;
				break;
			end
			
			if mask then
				local n = tonumber (mask);										-- convert to a number if it can be converted; nil else
				if n then
					 ~= n and string.rep("&mdash;", n) or nil;			-- make a string of (n > 0) mdashes, nil else, to replace name
					person.link = nil;											-- don't create link to name if name is replaces with mdash string or has been set nil
				else
																		-- replace name with mask text (must include name-list separator)
					sep_one = " ";												-- modify name-list separator
				end
			else
																-- get surname
				local first = person.first										-- get given name
				if utilities.is_set (first) then
					if ("vanc" == format) then									-- if Vancouver format
						 ('%.', '');								-- remove periods from surnames (http://www.ncbi.nlm.nih.gov/books/NBK7271/box/A35029/)
						if not person.corporate and is_good_vanc_name (one, first, nil, i) then		-- and name is all Latin characters; corporate authors not tested
							first = reduce_to_initials (first, i);				-- attempt to convert first name(s) to initials
						end
					end
					 .. namesep .. first;
				end
			end
			if utilities.is_set (person.link) then
				 (person.link, one);				-- link author/editor
			end
			if one then															-- if <one> has a value (name, mdash replacement, or mask text replacement)
				table.insert (name_list, one);									-- add it to the list of names
				table.insert (name_list, sep_one);								-- add the proper name-list separator
			end
		end
	end

	local count = #name_list / 2;												-- (number of names + number of separators) divided by 2
	if 0 < count then 
		if 1 < count and not etal then
			if 'amp' == format then
				name_list[#name_list-2] = " & ";								-- replace last separator with ampersand text
			elseif 'and' == format then
				if 2 == count then
					name_list[#name_list-2] = cfg.presentation.sep_nl_and;		-- replace last separator with 'and' text
				else
					name_list[#name_list-2] = cfg.presentation.sep_nl_end;		-- replace last separator with '(sep) and' text
				end
			end
		end
		name_list[#name_list] = nil;											-- erase the last separator
	end

	local result = table.concat (name_list);									-- construct list
	if etal and utilities.is_set (result) then									-- etal may be set by |display-authors=etal but we might not have a last-first list
		result = result .. sep .. ' ' .. cfg.messages['et al'];					-- we've got a last-first list and etal so add et al.
	end
	
	return result, count;														-- return name-list string and count of number of names (count used for editor names only)
end

--[[--------------------< M A K E _ C I T E R E F _ I D >-----------------------

Generates a CITEREF anchor ID if we have at least one name or a date.  Otherwise
returns an empty string.

namelist is one of the contributor-, author-, or editor-name lists chosen in that
order.  year is Year or anchor_year.

]]

local function make_citeref_id (namelist, year)
	local names={};							-- a table for the one to four names and year
	for i,v in ipairs (namelist) do			-- loop through the list and take up to the first four last names
		names[i] = v.last
		if i == 4 then break end			-- if four then done
	end
	table.insert (names, year);				-- add the year at the end
	local id = table.concat(names);			-- concatenate names and year for CITEREF id
	if utilities.is_set (id) then			-- if concatenation is not an empty string
		return "CITEREF" .. id;				-- add the CITEREF portion
	else
		return '';							-- return an empty string; no reason to include CITEREF id in this citation
	end
end


--[[---------------------< N A M E _ H A S _ E T A L >--------------------------

Evaluates the content of name parameters (author, editor, etc.) for variations on
the theme of et al.  If found, the et al. is removed, a flag is set to true and
the function returns the modified name and the flag.

This function never sets the flag to false but returns its previous state because
it may have been set by previous passes through this function or by the associated
|display-<names>=etal parameter

]]

local function name_has_etal (name, etal, nocat, param)

	if utilities.is_set (name) then												-- name can be nil in which case just return
		local patterns = cfg.et_al_patterns; 									-- get patterns from configuration
		
		for _, pattern in ipairs (patterns) do									-- loop through all of the patterns
			if name:match (pattern) then										-- if this 'et al' pattern is found in name
				name = name:gsub (pattern, '');									-- remove the offending text
				etal = true;													-- set flag (may have been set previously here or by |display-<names>=etal)
				if not nocat then												-- no categorization for |vauthors=
					table.insert( z.message_tail, {utilities.set_message ('err_etal', {param})});	-- and set an error if not added
				end
			end
		end
	end

	return name, etal;
end


--[[---------------------< N A M E _ I S _ N U M E R I C >----------------------

Add maint cat when name parameter value does not contain letters.  Does not catch
mixed alphanumeric names so |last=A. Green (1922-1987) does not get caught in the
current version of this test but |first=(1888) is caught.

returns nothing

]]

local function name_is_numeric (name, list_name)
	if utilities.is_set (name) then
		if mw.ustring.match (name, '^[%A]+$') then								-- when name does not contain any letters
			utilities.set_message ('maint_numeric_names', cfg.special_case_translation [list_name]);	-- add a maint cat for this template
		end
	end
end


--[[-------------------< N A M E _ H A S _ E D _ M A R K U P >------------------

Evaluates the content of author and editor parameters for extraneous editor annotations:
ed, ed., eds, (Ed.), etc. These annotations do not belong in author parameters and
are redundant in editor parameters.  If found, the function adds the editor markup
maintenance category.

returns nothing

]]

local function name_has_ed_markup (name, list_name)
	local patterns = cfg.editor_markup_patterns;								-- get patterns from configuration

	if utilities.is_set (name) then
		for _, pattern in ipairs (patterns) do									-- spin through patterns table and
			if name:match (pattern) then
				utilities.set_message ('maint_extra_text_names', cfg.special_case_translation [list_name]);	-- add a maint cat for this template
				break;
			end
		end
	end
end


--[[-----------------< N A M E _ H A S _ M U L T _ N A M E S >------------------

Evaluates the content of last/surname (authors etc.) parameters for multiple names.
Multiple names are indicated if there is more than one comma or any "unescaped"
semicolons. Escaped semicolons are ones used as part of selected HTML entities.
If the condition is met, the function adds the multiple name maintenance category.

returns nothing

]]

local function name_has_mult_names (name, list_name)
	local _, commas, semicolons, nbsps;
	if utilities.is_set (name) then
		_, commas = name:gsub (',', '');										-- count the number of commas
		_, semicolons = name:gsub (';', '');									-- count the number of semicolons
		-- nbsps probably should be its own separate count rather than merged in
		-- some way with semicolons because Lua patterns do not support the
		-- grouping operator that regex does, which means there is no way to add
		-- more entities to escape except by adding more counts with the new
		-- entities
		_, nbsps = name:gsub ('&nbsp;','');										-- count nbsps
		
		-- There is exactly 1 semicolon per &nbsp; entity, so subtract nbsps
		-- from semicolons to 'escape' them. If additional entities are added,
		-- they also can be subtracted.
		if 1 < commas or 0 < (semicolons - nbsps) then
			utilities.set_message ('maint_mult_names', cfg.special_case_translation [list_name]);	-- add a maint message
		end
	end
end


--[[------------------------< N A M E _ C H E C K S >---------------------------

This function calls various name checking functions used to validate the content
of the various name-holding parameters.

]]

local function name_checks (last, first, list_name)
	local accept_name;

	if utilities.is_set (last) then
		last, accept_name = utilities.has_accept_as_written (last);				-- remove accept-this-as-written markup when it wraps all of <last>
		
		if not accept_name then													-- <last> not wrapped in accept-as-written markup
			name_has_mult_names (last, list_name);								-- check for multiple names in the parameter (last only)
			name_has_ed_markup (last, list_name);								-- check for extraneous 'editor' annotation
			name_is_numeric (last, list_name);									-- check for names that are composed of digits and punctuation
		end
	end

	if utilities.is_set (first) then
		first, accept_name = utilities.has_accept_as_written (first);			-- remove accept-this-as-written markup when it wraps all of <first>

		if not accept_name then													-- <first> not wrapped in accept-as-written markup
			name_has_ed_markup (first, list_name);								-- check for extraneous 'editor' annotation
			name_is_numeric (first, list_name);									-- check for names that are composed of digits and punctuation
		end
	end

	return last, first;															-- done
end


--[[----------------------< E X T R A C T _ N A M E S >-------------------------
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=.

When an author or editor parameter contains some form of 'et al.', the 'et al.'
is stripped from the parameter and a flag (etal) returned that will cause list_people()
to add the static 'et al.' text from Module:Citation/CS1/Configuration.  This keeps
'et al.' out of the template's metadata.  When this occurs, an error is emitted.

]]

local function extract_names(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 etal = false;															-- return value set to true when we find some form of et al. in an author parameter

	local last_alias, first_alias, link_alias;									-- selected parameter aliases used in error messaging
	while true do
		last, last_alias = utilities.select_one ( args, cfg.aliases[list_name .. '-Last'], 'err_redundant_parameters', i );		-- search through args for name components beginning at 1
		first, first_alias = utilities.select_one ( args, cfg.aliases[list_name .. '-First'], 'err_redundant_parameters', i );
		link, link_alias = utilities.select_one ( args, cfg.aliases[list_name .. '-Link'], 'err_redundant_parameters', i );
		mask = utilities.select_one ( args, cfg.aliases[list_name .. '-Mask'], 'err_redundant_parameters', i );

		last, etal = name_has_etal (last, etal, false, last_alias);				-- find and remove variations on et al.
		first, etal = name_has_etal (first, etal, false, first_alias);			-- find and remove variations on et al.
		last, first = name_checks (last, first, list_name);						-- multiple names, extraneous annotation, etc. checks
		
		if first and not last then												-- if there is a firstn without a matching lastn
			local alias = first_alias:find ('given', 1, true) and 'given' or 'first';	-- get first or given form of the alias
			table.insert (z.message_tail, { utilities.set_message ( 'err_first_missing_last', {
				first_alias,													-- param name of alias missing its mate
				first_alias:gsub (alias, {['first'] = 'last', ['given'] = 'surname'}),	-- make param name appropriate to the alias form
				}, 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
			local result;
			link = link_title_ok (link, link_alias, last, last_alias);			-- check for improper wiki-markup
			if first then
				link = link_title_ok (link, link_alias, first, first_alias);	-- check for improper wiki-markup
			end

			names[n] = {last = last, first = first, link = link, mask = mask, corporate = false};	-- add this name to our names list (corporate for |vauthors= only)
			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, { utilities.set_message ( 'err_missing_name', {list_name:match ("(%w+)List"):lower(), 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, etal;															-- all done, return our list of names and the etal flag
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 or 639-2 code.

Returns the language name and associated two- or three-character 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(<local wiki language>, 'all') returns a list of
languages that in some cases may include extensions. For example, code 'cbk-zam'
and its associated name 'Chavacano de Zamboanga' (MediaWiki does not support
code 'cbk' or name 'Chavacano'.  Most (all?) of these languages are not used a
'language' codes per se, rather they are used as sub-domain names: cbk-zam.wikipedia.org.
A list of language names and codes supported by fetchLanguageNames() can be found
at Template:Citation Style documentation/language/doc

Names that are included in the list will be found if that name is provided in the
|language= parameter.  For example, if |language=Chavacano de Zamboanga, that name
will be found with the associated code 'cbk-zam'.  When names are found and the
associated code is not two or three characters, this function returns only the
WikiMedia language name.

Some language names have multiple entries under different codes:
	Aromanian has code rup and code roa-rup
When this occurs, this function returns the language name and the 2- or 3-character code

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

]]

local function get_iso639_code (lang, this_wiki_code)
	if cfg.lang_name_remap[lang:lower()] then									-- if there is a remapped name (because MediaWiki uses something that we don't think is correct)
		return cfg.lang_name_remap[lang:lower()][1], cfg.lang_name_remap[lang:lower()][2];	-- for this language 'name', return a possibly new name and appropriate code
	end

	local ietf_code;															-- because some languages have both IETF-like codes and ISO 639-like codes
	local ietf_name;
	
	local langlc = mw.ustring.lower (lang);										-- lower-case version for comparisons

	for code, name in pairs (cfg.languages) do									-- scan the list to see if we can find our language
		if langlc == mw.ustring.lower (name) then
			if 2 == #code or 3 == #code then									-- two- or three-character codes only; IETF extensions not supported
				return name, code;												-- so return the name and the code
			end
			ietf_code = code;													-- remember that we found an IETF-like code and save its name
			ietf_name = name;													-- but keep looking for a 2- or 3-char code
		end
	end
																				-- didn't find name with 2- or 3-char code; if IETF-like code found return
	return ietf_code and ietf_name or lang;										-- associated name; return original language text else
end


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

Gets language name from a provided two- or three-character ISO 639 code.  If a code
is recognized by MediaWiki, use the returned name; if not, then use the value that
was provided with the language parameter.

When |language= contains a recognized language (either code or name), the page is
assigned to the category for that code: Category:Norwegian-language sources (no).
For valid three-character code languages, the page is assigned to the single category
for '639-2' codes: Category:CS1 ISO 639-2 language sources.

Languages that are the same as the local wiki are not categorized.  MediaWiki does
not recognize three-character equivalents of two-character codes: code 'ar' is
recognized but code 'ara' is not.

This function supports multiple languages in the form |language=nb, French, th
where the language names or codes are separated from each other by commas with
optional space characters.

]]

local function language_parameter (lang)
	local code;																	-- the two- or three-character language code
	local name;																	-- the language name
	local language_list = {};													-- table of language names to be rendered
	local names_table = {};														-- table made from the value assigned to |language=

	local this_wiki_name = mw.language.fetchLanguageName (cfg.this_wiki_code, cfg.this_wiki_code);	-- get this wiki's language name

	names_table = mw.text.split (lang, '%s*,%s*');								-- names should be a comma separated list

	for _, lang in ipairs (names_table) do										-- reuse lang
		name = cfg.lang_code_remap[lang:lower()];								-- first see if this is a code that is not supported by MediaWiki but is in remap

		if name then															-- there was a remapped code so
			if not lang:match ('^%a%a%a?%-x%-%a+$') then						-- if not a private IETF tag
				lang = lang:gsub ('^(%a%a%a?)%-.*', '%1');						-- strip IETF tags from code
			end
		else
			lang = lang:gsub ('^(%a%a%a?)%-.*', '%1');							-- strip any IETF-like tags from code
			if 2 == lang:len() or 3 == lang:len() then							-- if two-or three-character code
				name = mw.language.fetchLanguageName (lang:lower(), cfg.this_wiki_code);	-- get language name if |language= is a proper code
			end
		end

		if utilities.is_set (name) then											-- if |language= specified a valid code
			code = lang:lower();												-- save it
		else
			name, code = get_iso639_code (lang, cfg.this_wiki_code);			-- attempt to get code from name (assign name here so that we are sure of proper capitalization)
		end
		name = mw.ustring.gsub(name, "^[Tt]iếng ", "", 1)
	
		if utilities.is_set (code) then											-- only 2- or 3-character codes
			name = cfg.lang_code_remap[code] or name;							-- override wikimedia when they misuse language codes/names

			if cfg.this_wiki_code ~= code then									-- when the language is not the same as this wiki's language
				if 2 == code:len() then											-- and is a two-character code
					utilities.add_prop_cat ('foreign_lang_source' .. code, {name, code});	-- categorize it; code appended to allow for multiple language categorization
				else															-- or is a recognized language (but has a three-character code)
					utilities.add_prop_cat ('foreign_lang_source_2' .. code, {code});		-- categorize it differently TODO: support multiple three-character code categories per cs1|2 template
				end
			elseif cfg.local_lang_cat_enable then								-- when the language and this wiki's language are the same and categorization is enabled
				utilities.add_prop_cat ('local_lang_source', {name, code});		-- categorize it
			end
		else
			utilities.set_message ('maint_unknown_lang');						-- add maint category if not already added
		end
		
		table.insert (language_list, name);
		name = '';																-- so we can reuse it
	end
 
	name = utilities.make_sep_list (#language_list, language_list);

	this_wiki_name = mw.ustring.gsub(this_wiki_name, "^[Tt]iếng ", "", 1)
	if this_wiki_name == name then
		return '';																-- if one language and that language is this wiki's return an empty string (no annotation)
	end
	return (" " .. wrap_msg ('language', name));								-- otherwise wrap with '(in ...)'
	--[[ TODO: should only return blank or name rather than full list
	so we can clean up the bunched parenthetical elements Language, Type, Format
	]]
end

--[[-----------------------< S E T _ C S _ S T Y L E >--------------------------
Gets the default CS style configuration for the given mode.
Returns default separator and either postscript as passed in or the default.
In CS1, the default postscript and separator are '.'.
In CS2, the default postscript is the empty string and the default separator is ','.
]]
local function set_cs_style (postscript, mode)
	if utilities.is_set(postscript) then
		-- emit a maintenance message if user postscript is the default cs1 postscript
		-- we catch the opposite case for cs2 in set_style
		if mode == 'cs1' and postscript == cfg.presentation['ps_' .. mode] then
			utilities.set_message ('maint_postscript');
		end
	else
		postscript = cfg.presentation['ps_' .. mode];
	end
	return cfg.presentation['sep_' .. mode], postscript;
end

--[[--------------------------< S E T _ S T Y L E >-----------------------------
Sets the separator and postscript styles. Checks the |mode= first and the
#invoke CitationClass second. Removes the postscript if postscript == none.
]]
local function set_style (mode, postscript, cite_class)
	local sep;
	if 'cs2' == mode then
		sep, postscript = set_cs_style (postscript, 'cs2');
	elseif 'cs1' == mode then
		sep, postscript = set_cs_style (postscript, 'cs1');
	elseif 'citation' == cite_class	then
		sep, postscript = set_cs_style (postscript, 'cs2');
	else
		sep, postscript = set_cs_style (postscript, 'cs1');
	end

	if cfg.keywords_xlate[postscript:lower()] == 'none' then
		-- emit a maintenance message if user postscript is the default cs2 postscript
		-- we catch the opposite case for cs1 in set_cs_style
		if 'cs2' == mode or 'citation' == cite_class then
			utilities.set_message ('maint_postscript');
		end
		postscript = '';
	end
	
	return sep, postscript
end

--[=[-------------------------< I S _ P D F >-----------------------------------

Determines if a URL has the file extension that is one of the PDF file extensions
used by [[MediaWiki:Common.css]] when applying the PDF icon to external links.

returns true if file extension is one of the recognized extensions, else false

]=]

local function is_pdf (url)
	return url:match ('%.pdf$') or url:match ('%.PDF$') or
		url:match ('%.pdf[%?#]') or url:match ('%.PDF[%?#]') or
		url:match ('%.PDF&#035') or url:match ('%.pdf&#035');
end


--[[--------------------------< S T Y L E _ F O R M A T >-----------------------

Applies CSS style to |format=, |chapter-format=, etc.  Also emits an error message
if the format parameter does not have a matching URL parameter.  If the format parameter
is not set and the URL contains a file extension that is recognized as a PDF document
by MediaWiki's commons.css, this code will set the format parameter to (PDF) with
the appropriate styling.

]]

local function style_format (format, url, fmt_param, url_param)
	if utilities.is_set (format) then
		format = utilities.wrap_style ('format', format);						-- add leading space, parentheses, resize
		if not utilities.is_set (url) then
			format = format .. ' ' .. utilities.set_message ( 'err_format_missing_url', {fmt_param, url_param} );	-- add an error message
		end
	elseif is_pdf (url) then													-- format is not set so if URL is a PDF file then
		format = utilities.wrap_style ('format', 'PDF');						-- set format to PDF
	else
		format = '';															-- empty string for concatenation
	end
	return format;
end


--[[---------------------< G E T _ D I S P L A Y _ N A M E S >------------------

Returns a number that defines the number of names displayed for author and editor
name lists and a Boolean flag to indicate when et al. should be appended to the name list.

When the value assigned to |display-xxxxors= is a number greater than or equal to zero,
return the number and the previous state of the 'etal' flag (false by default
but may have been set to true if the name list contains some variant of the text 'et al.').

When the value assigned to |display-xxxxors= is the keyword 'etal', return a number
that is one greater than the number of authors in the list and set the 'etal' flag true.
This will cause the list_people() to display all of the names in the name list followed by 'et al.'

In all other cases, returns nil and the previous state of the 'etal' flag.

inputs:
	max: A['DisplayAuthors'] or A['DisplayEditors']; a number or some flavor of etal
	count: #a or #e
	list_name: 'authors' or 'editors'
	etal: author_etal or editor_etal

]]

local function get_display_names (max, count, list_name, etal, param)
	if utilities.is_set (max) then
		if 'etal' == max:lower():gsub("[ '%.]", '') then						-- the :gsub() portion makes 'etal' from a variety of 'et al.' spellings and stylings
			max = count + 1;													-- number of authors + 1 so display all author name plus et al.
			etal = true;														-- overrides value set by extract_names()
		elseif max:match ('^%d+$') then											-- if is a string of numbers
			max = tonumber (max);												-- make it a number
			if max >= count then												-- if |display-xxxxors= value greater than or equal to number of authors/editors
				table.insert( z.message_tail, {utilities.set_message ('err_disp_name', {param, max}, true)});	-- add error message
				max = nil;
			end
		else																	-- not a valid keyword or number
			table.insert( z.message_tail, {utilities.set_message ('err_disp_name', {param, max}, true)});		-- add error message
			max = nil;															-- unset; as if |display-xxxxors= had not been set
		end
	end
	
	return max, etal;
end


--[[----------< E X T R A _ T E X T _ I N _ P A G E _ C H E C K >---------------

Adds error if |page=, |pages=, |quote-page=, |quote-pages= has what appears to be
some form of p. or pp. abbreviation in the first characters of the parameter content.

check page for extraneous p, p., pp, pp., pg, pg. at start of parameter value:
	good pattern: '^P[^%.P%l]' matches when page begins PX or P# but not Px
		      where x and X are letters and # is a digit
	bad pattern:  '^[Pp][PpGg]' matches when page begins pp, pP, Pp, PP, pg, pG, Pg, PG

]]

local function extra_text_in_page_check (val, name)
	if not val:match (cfg.vol_iss_pg_patterns.good_ppattern) then
		for _, pattern in ipairs (cfg.vol_iss_pg_patterns.bad_ppatterns) do		-- spin through the selected sequence table of patterns
			if val:match (pattern) then											-- when a match, error so
				table.insert (z.message_tail, {utilities.set_message ('err_extra_text_pages', {name}, true)}); -- add error message
				return;															-- and done
			end
		end
	end		
end


--[[--------------------------< E X T R A _ T E X T _ I N _ V O L _ I S S _ C H E C K >------------------------

Adds error if |volume= or |issue= has what appears to be some form of redundant 'type' indicator.

For |volume=:
	'V.', or 'Vol.' (with or without the dot) abbreviations or 'Volume' in the first characters of the parameter
	content (all case insensitive). 'V' and 'v' (without the dot) are presumed to be roman numerals so
	are allowed.

For |issue=:
	'No.', 'I.', 'Iss.' (with or without the dot) abbreviations, or 'Issue' in the first characters of the
	parameter content (all case insensitive).
	
Single character values ('v', 'i', 'n') allowed when not followed by separator character ('.', ':', '=', or
whitespace character) – param values are trimmed of whitespace by MediaWiki before delivered to the module.
	
<val> is |volume= or |issue= parameter value
<name> is |volume= or |issue= parameter name for error message
<selector> is 'v' for |volume=, 'i' for |issue=

sets error message on failure; returns nothing

]]

local function extra_text_in_vol_iss_check (val, name, selector)
	if not utilities.is_set (val) then
		return;
	end
	
	local patterns = 'v' == selector and cfg.vol_iss_pg_patterns.vpatterns or cfg.vol_iss_pg_patterns.ipatterns;

	local handler = 'v' == selector and 'err_extra_text_volume' or 'err_extra_text_issue';
	val = val:lower();															-- force parameter value to lower case
	for _, pattern in ipairs (patterns) do										-- spin through the selected sequence table of patterns
		if val:match (pattern) then												-- when a match, error so
			table.insert (z.message_tail, {utilities.set_message (handler, {name}, true)}); -- add error message
			return;																-- and done
		end
	end
end


--[=[-------------------------< G E T _ V _ N A M E _ T A B L E >----------------------------------------------

split apart a |vauthors= or |veditors= parameter.  This function allows for corporate names, wrapped in doubled
parentheses to also have commas; in the old version of the code, the doubled parentheses were included in the
rendered citation and in the metadata.  Individual author names may be wikilinked

	|vauthors=Jones AB, [[E. B. White|White EB]], ((Black, Brown, and Co.))

]=]

local function get_v_name_table (vparam, output_table, output_link_table)
	local name_table = mw.text.split(vparam, "%s*,%s*");						-- names are separated by commas
	local wl_type, label, link;													-- wl_type not used here; just a placeholder
	
	local i = 1;
	
	while name_table[i] do
		if name_table[i]:match ('^%(%(.*[^%)][^%)]$') then						-- first segment of corporate with one or more commas; this segment has the opening doubled parentheses
			local name = name_table[i];
			i = i + 1;															-- bump indexer to next segment
			while name_table[i] do
				name = name .. ', ' .. name_table[i];							-- concatenate with previous segments
				if name_table[i]:match ('^.*%)%)$') then						-- if this table member has the closing doubled parentheses
					break;														-- and done reassembling so
				end
				i = i + 1;														-- bump indexer
			end
			table.insert (output_table, name);									-- and add corporate name to the output table
			table.insert (output_link_table, '');								-- no wikilink
		else
			wl_type, label, link = utilities.is_wikilink (name_table[i]);		-- wl_type is: 0, no wl (text in label variable); 1, [[D]]; 2, [[L|D]]
			table.insert (output_table, label);									-- add this name
			if 1 == wl_type then
				table.insert (output_link_table, label);						-- simple wikilink [[D]]
			else
				table.insert (output_link_table, link);							-- no wikilink or [[L|D]]; add this link if there is one, else empty string
			end
		end
		i = i + 1;
	end	
	return output_table;
end


--[[--------------------------< P A R S E _ V A U T H O R S _ V E D I T O R S >--------------------------------

This function extracts author / editor names from |vauthors= or |veditors= and finds matching |xxxxor-maskn= and
|xxxxor-linkn= in args.  It then returns a table of assembled names just as extract_names() does.

Author / editor names in |vauthors= or |veditors= must be in Vancouver system style. Corporate or institutional names
may sometimes be required and because such names will often fail the is_good_vanc_name() and other format compliance
tests, are wrapped in doubled parentheses ((corporate name)) to suppress the format tests.

Supports generational suffixes Jr, 2nd, 3rd, 4th–6th.

This function sets the Vancouver error when a required comma is missing and when there is a space between an author's initials.

]]

local function parse_vauthors_veditors (args, vparam, list_name)
	local names = {};															-- table of names assembled from |vauthors=, |author-maskn=, |author-linkn=
	local v_name_table = {};
	local v_link_table = {};													-- when name is wikilinked, targets go in this table
	local etal = false;															-- return value set to true when we find some form of et al. vauthors parameter
	local last, first, link, mask, suffix;
	local corporate = false;

	vparam, etal = name_has_etal (vparam, etal, true);							-- find and remove variations on et al. do not categorize (do it here because et al. might have a period)
	v_name_table = get_v_name_table (vparam, v_name_table, v_link_table);		-- names are separated by commas

	for i, v_name in ipairs(v_name_table) do
		first = '';																-- set to empty string for concatenation and because it may have been set for previous author/editor
		local accept_name;
		v_name, accept_name = utilities.has_accept_as_written (v_name);			-- remove accept-this-as-written markup when it wraps all of <v_name>

		if accept_name then
			last = v_name;
			corporate = true;													-- flag used in list_people()
		elseif string.find(v_name, "%s") then
			if v_name:find('[;%.]') then										-- look for commonly occurring punctuation characters; 
				add_vanc_error (cfg.err_msg_supl.punctuation, i);
			end
			local lastfirstTable = {}
			lastfirstTable = mw.text.split(v_name, "%s+")
			first = table.remove(lastfirstTable);								-- removes and returns value of last element in table which should be initials or generational suffix

			if not mw.ustring.match (first, '^%u+$') then						-- mw.ustring here so that later we will catch non-Latin characters
				suffix = first;													-- not initials so assume that whatever we got is a generational suffix
				first = table.remove(lastfirstTable);							-- get what should be the initials from the table
			end
			last = table.concat(lastfirstTable, ' ')							-- returns a string that is the concatenation of all other names that are not initials and generational suffix
			if not utilities.is_set (last) then
				first = '';														-- unset
				last = v_name;													-- last empty because something wrong with first
				add_vanc_error (cfg.err_msg_supl.name, i);
			end
			if mw.ustring.match (last, '%a+%s+%u+%s+%a+') then
				add_vanc_error (cfg.err_msg_supl['missing comma'], i);			-- matches last II last; the case when a comma is missing
			end
			if mw.ustring.match (v_name, ' %u %u$') then						-- this test is in the wrong place TODO: move or replace with a more appropriate test
				add_vanc_error (cfg.err_msg_supl.initials, i);					-- matches a space between two initials
			end
		else
			last = v_name;														-- last name or single corporate name?  Doesn't support multiword corporate names? do we need this?
		end
		
		if utilities.is_set (first) then
			if not mw.ustring.match (first, "^%u?%u$") then						-- first shall contain one or two upper-case letters, nothing else
				add_vanc_error (cfg.err_msg_supl.initials, i);					-- too many initials; mixed case initials (which may be ok Romanization); hyphenated initials
			end
			is_good_vanc_name (last, first, suffix, i);							-- check first and last before restoring the suffix which may have a non-Latin digit
			if utilities.is_set (suffix) then
				first = first .. ' ' .. suffix;									-- if there was a suffix concatenate with the initials
				suffix = '';													-- unset so we don't add this suffix to all subsequent names
			end
		else
			if not corporate then
				is_good_vanc_name (last, '', nil, i);
			end
		end

		link = utilities.select_one ( args, cfg.aliases[list_name .. '-Link'], 'err_redundant_parameters', i ) or v_link_table[i];
		mask = utilities.select_one ( args, cfg.aliases[list_name .. '-Mask'], 'err_redundant_parameters', i );
		names[i] = {last = last, first = first, link = link, mask = mask, corporate = corporate};		-- add this assembled name to our names list
	end
	return names, etal;															-- all done, return our list of names
end


--[[--------------------------< S E L E C T _ A U T H O R _ E D I T O R _ S O U R C E >------------------------

Select one of |authors=, |authorn= / |lastn / firstn=, or |vauthors= as the source of the author name list or
select one of |editorn= / editor-lastn= / |editor-firstn= or |veditors= as the source of the editor name list.

Only one of these appropriate three will be used.  The hierarchy is: |authorn= (and aliases) highest and |authors= lowest;
|editorn= (and aliases) highest and |veditors= lowest (support for |editors= withdrawn)

When looking for |authorn= / |editorn= parameters, test |xxxxor1= and |xxxxor2= (and all of their aliases); stops after the second
test which mimicks the test used in extract_names() when looking for a hole in the author name list.  There may be a better
way to do this, I just haven't discovered what that way is.

Emits an error message when more than one xxxxor name source is provided.

In this function, vxxxxors = vauthors or veditors; xxxxors = authors as appropriate.

]]

local function select_author_editor_source (vxxxxors, xxxxors, args, list_name)
	local lastfirst = false;
	if utilities.select_one ( args, cfg.aliases[list_name .. '-Last'], 'none', 1 ) or		-- do this twice in case we have a |first1= without a |last1=; this ...
		utilities.select_one ( args, cfg.aliases[list_name .. '-First'], 'none', 1 ) or		-- ... also catches the case where |first= is used with |vauthors=
		utilities.select_one ( args, cfg.aliases[list_name .. '-Last'], 'none', 2 ) or
		utilities.select_one ( args, cfg.aliases[list_name .. '-First'], 'none', 2 ) then
			lastfirst = true;
	end

	if (utilities.is_set (vxxxxors) and true == lastfirst) or					-- these are the three error conditions
		(utilities.is_set (vxxxxors) and utilities.is_set (xxxxors)) or
		(true == lastfirst and utilities.is_set (xxxxors)) then
			local err_name;
			if 'AuthorList' == list_name then									-- figure out which name should be used in error message
				err_name = 'author';
			else
				err_name = 'editor';
			end
			table.insert( z.message_tail, { utilities.set_message ( 'err_redundant_parameters',
				{err_name .. '-name-list parameters'}, true ) } );				-- add error message
	end

	if true == lastfirst then return 1 end;										-- return a number indicating which author name source to use
	if utilities.is_set (vxxxxors) then return 2 end;
	if utilities.is_set (xxxxors) then return 3 end;
	return 1;																	-- no authors so return 1; this allows missing author name test to run in case there is a first without last 
end


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

This function is used to validate a parameter's assigned value for those parameters that have only a limited number
of allowable values (yes, y, true, live, dead, etc.).  When the parameter value has not been assigned a value (missing
or empty in the source template) the function returns the value specified by ret_val.  If the parameter value is one
of the list of allowed values returns the translated value; else, emits an error message and returns the value
specified by ret_val.

]]

local function is_valid_parameter_value (value, name, possible, ret_val)
	if not utilities.is_set (value) then
		return ret_val;															-- an empty parameter is ok
	elseif utilities.in_array (value, possible) then
		return cfg.keywords_xlate[value];										-- return translation of parameter keyword
	else
		table.insert( z.message_tail, { utilities.set_message ( 'err_invalid_param_val', {name, value}, true ) } );	-- not an allowed value so add error message
		return ret_val;
	end
end


--[[--------------------------< T E R M I N A T E _ N A M E _ L I S T >----------------------------------------

This function terminates a name list (author, contributor, editor) with a separator character (sepc) and a space
when the last character is not a sepc character or when the last three characters are not sepc followed by two
closing square brackets (close of a wikilink).  When either of these is true, the name_list is terminated with a
single space character.

]]

local function terminate_name_list (name_list, sepc)
	if (string.sub (name_list, -3, -1) == sepc .. '. ') then					-- if already properly terminated
		return name_list;														-- just return the name list
	elseif (string.sub (name_list, -1, -1) == sepc) or (string.sub (name_list, -3, -1) == sepc .. ']]') then	-- if last name in list ends with sepc char
		return name_list .. " ";												-- don't add another
	else
		return name_list .. sepc .. ' ';										-- otherwise terminate the name list
	end
end


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

returns the concatenation of the formatted volume and issue parameters as a single string; or formatted volume
or formatted issue, or an empty string if neither are set.

]]
	
local function format_volume_issue (volume, issue, cite_class, origin, sepc, lower)
	if not utilities.is_set (volume) and not utilities.is_set (issue) then
		return '';
	end
	
	if 'magazine' == cite_class or (utilities.in_array (cite_class, {'citation', 'map'}) and 'magazine' == origin) then
		if utilities.is_set (volume) and utilities.is_set (issue) then
			return wrap_msg ('vol-no', {sepc, hyphen_to_dash (volume), issue}, lower);
		elseif utilities.is_set (volume) then
			return wrap_msg ('vol', {sepc, hyphen_to_dash (volume)}, lower);
		else
			return wrap_msg ('issue', {sepc, issue}, lower);
		end
	end

	if 'podcast' == cite_class and utilities.is_set (issue) then
		return wrap_msg ('issue', {sepc, issue}, lower);
	end

	local vol = '';																-- here for all cites except magazine
		
	if utilities.is_set (volume) then
		if volume:match ('^[MDCLXVI]+$') or volume:match ('^%d+$') then			-- volume value is all digits or all uppercase Roman numerals
			vol = utilities.substitute (cfg.presentation['vol-bold'], {sepc, volume});	-- render in bold face
		elseif (4 < mw.ustring.len(volume)) then								-- not all digits or Roman numerals and longer than 4 characters
			vol = utilities.substitute (cfg.messages['j-vol'], {sepc, hyphen_to_dash (volume)});	-- not bold
			utilities.add_prop_cat ('long_vol');
		else																	-- four or less characters
			vol = utilities.substitute (cfg.presentation['vol-bold'], {sepc, hyphen_to_dash (volume)});	-- bold
		end
	end
	if utilities.is_set (issue) then
		return vol .. utilities.substitute (cfg.messages['j-issue'], issue);
	end
	return vol;
end


--[[-------------------------< F O R M A T _ P A G E S _ S H E E T S >-----------------------------------------

adds static text to one of |page(s)= or |sheet(s)= values and returns it with all of the others set to empty strings.
The return order is:
	page, pages, sheet, sheets

Singular has priority over plural when both are provided.

]]

local function format_pages_sheets (page, pages, sheet, sheets, cite_class, origin, sepc, nopp, lower)
	if 'map' == cite_class then													-- only cite map supports sheet(s) as in-source locators
		if utilities.is_set (sheet) then
			if 'journal' == origin then
				return '', '', wrap_msg ('j-sheet', sheet, lower), '';
			else
				return '', '', wrap_msg ('sheet', {sepc, sheet}, lower), '';
			end
		elseif utilities.is_set (sheets) then
			if 'journal' == origin then
				return '', '', '', wrap_msg ('j-sheets', sheets, lower);
			else
				return '', '', '', wrap_msg ('sheets', {sepc, sheets}, lower);
			end
		end
	end

	local is_journal = 'journal' == cite_class or (utilities.in_array (cite_class, {'citation', 'map', 'interview'}) and 'journal' == origin);
	
	if utilities.is_set (page) then
		if is_journal then
			return utilities.substitute (cfg.messages['j-page(s)'], page), '', '', '';
		elseif not nopp then
			return utilities.substitute (cfg.messages['p-prefix'], {sepc, page}), '', '', '';
		else
			return utilities.substitute (cfg.messages['nopp'], {sepc, page}), '', '', '';
		end
	elseif utilities.is_set (pages) then
		if is_journal then
			return utilities.substitute (cfg.messages['j-page(s)'], pages), '', '', '';
		elseif tonumber(pages) ~= nil and not nopp then							-- if pages is only digits, assume a single page number
			return '', utilities.substitute (cfg.messages['p-prefix'], {sepc, pages}), '', '';
		elseif not nopp then
			return '', utilities.substitute (cfg.messages['pp-prefix'], {sepc, pages}), '', '';
		else
			return '', utilities.substitute (cfg.messages['nopp'], {sepc, pages}), '', '';
		end
	end
	
	return '', '', '', '';														-- return empty strings
end


--[[--------------------------< I N S O U R C E _ L O C _ G E T >----------------------------------------------

returns one of the in-source locators: page, pages, or at. 

If any of these are interwiki links to Wikisource, returns the label portion of the interwiki-link as plain text
for use in COinS.  This COinS thing is done because here we convert an interwiki-link to an external link and
add an icon span around that; get_coins_pages() doesn't know about the span.  TODO: should it?  

TODO: add support for sheet and sheets?; streamline;

TODO: make it so that this function returns only one of the three as the single in-source (the return value assigned
to a new name)?

]]

local function insource_loc_get (page, page_orig, pages, pages_orig, at)
	local ws_url, ws_label, coins_pages, L;										-- for Wikisource interwiki-links; TODO: this corrupts page metadata (span remains in place after cleanup; fix there?)

	if utilities.is_set (page) then
		if utilities.is_set (pages) or utilities.is_set (at) then
			pages = '';															-- unset the others
			at = '';
		end
		extra_text_in_page_check (page, page_orig);								-- emit error message when |page= value begins with what looks like p., pp., etc.

		ws_url, ws_label, L = wikisource_url_make (page);						-- make ws URL from |page= interwiki link; link portion L becomes tooltip label
		if ws_url then
			page = external_link (ws_url, ws_label .. '&nbsp;', 'ws link in page');	-- space char after label to move icon away from in-source text; TODO: a better way to do this?
			page = utilities.substitute (cfg.presentation['interwiki-icon'], {cfg.presentation['class-wikisource'], L, page});
			coins_pages = ws_label;
		end
	elseif utilities.is_set (pages) then
		if utilities.is_set (at) then
			at = '';															-- unset
		end
		extra_text_in_page_check (pages, pages_orig);							-- emit error message when |page= value begins with what looks like p., pp., etc.

		ws_url, ws_label, L = wikisource_url_make (pages);						-- make ws URL from |pages= interwiki link; link portion L becomes tooltip label
		if ws_url then
			pages = external_link (ws_url, ws_label .. '&nbsp;', 'ws link in pages');	-- space char after label to move icon away from in-source text; TODO: a better way to do this?
			pages = utilities.substitute (cfg.presentation['interwiki-icon'], {cfg.presentation['class-wikisource'], L, pages});
			coins_pages = ws_label;
		end
	elseif utilities.is_set (at) then
		ws_url, ws_label, L = wikisource_url_make (at);							-- make ws URL from |at= interwiki link; link portion L becomes tooltip label
		if ws_url then
			at = external_link (ws_url, ws_label .. '&nbsp;', 'ws link in at');	-- space char after label to move icon away from in-source text; TODO: a better way to do this?
			at = utilities.substitute (cfg.presentation['interwiki-icon'], {cfg.presentation['class-wikisource'], L, at});
			coins_pages = ws_label;
		end
	end
	
	return page, pages, at, coins_pages;
end

--[[--------------------------< I S _ U N I Q U E _ A R C H I V E _ U R L >------------------------------------

add error message when |archive-url= value is same as |url= or chapter-url= (or alias...) value

]]

local function is_unique_archive_url (archive, url, c_url, source, date)
	if utilities.is_set (archive) then
		if archive == url or archive == c_url then
			table.insert (z.message_tail, {utilities.set_message ('err_bad_url', {utilities.wrap_style ('parameter', source)}, true)});	-- add error message
			return '', '';														-- unset |archive-url= and |archive-date= because same as |url= or |chapter-url=
		end
	end

	return archive, date;
end


--[=[-------------------------< A R C H I V E _ U R L _ C H E C K >--------------------------------------------

Check archive.org URLs to make sure they at least look like they are pointing at valid archives and not to the 
save snapshot URL or to calendar pages.  When the archive URL is 'https://web.archive.org/save/' (or http://...)
archive.org saves a snapshot of the target page in the URL.  That is something that Wikipedia should not allow
unwitting readers to do.

When the archive.org URL does not have a complete timestamp, archive.org chooses a snapshot according to its own
algorithm or provides a calendar 'search' result.  [[WP:ELNO]] discourages links to search results.

This function looks at the value assigned to |archive-url= and returns empty strings for |archive-url= and
|archive-date= and an error message when:
	|archive-url= holds an archive.org save command URL
	|archive-url= is an archive.org URL that does not have a complete timestamp (YYYYMMDDhhmmss 14 digits) in the
		correct place
otherwise returns |archive-url= and |archive-date=

There are two mostly compatible archive.org URLs:
	//web.archive.org/<timestamp>...		-- the old form
	//web.archive.org/web/<timestamp>...	-- the new form

The old form does not support or map to the new form when it contains a display flag.  There are four identified flags
('id_', 'js_', 'cs_', 'im_') but since archive.org ignores others following the same form (two letters and an underscore)
we don't check for these specific flags but we do check the form.

This function supports a preview mode.  When the article is rendered in preview mode, this function may return a modified
archive URL:
	for save command errors, return undated wildcard (/*/)
	for timestamp errors when the timestamp has a wildcard, return the URL unmodified
	for timestamp errors when the timestamp does not have a wildcard, return with timestamp limited to six digits plus wildcard (/yyyymm*/)

]=]

local function archive_url_check (url, date)
	local err_msg = '';															-- start with the error message empty
	local path, timestamp, flag;												-- portions of the archive.org URL
	
	if (not url:match('//web%.archive%.org/')) and (not url:match('//liveweb%.archive%.org/')) then		-- also deprecated liveweb Wayback machine URL
		return url, date;														-- not an archive.org archive, return ArchiveURL and ArchiveDate
	end

	if url:match('//web%.archive%.org/save/') then								-- if a save command URL, we don't want to allow saving of the target page 
		err_msg = cfg.err_msg_supl.save;
		url = url:gsub ('(//web%.archive%.org)/save/', '%1/*/', 1);				-- for preview mode: modify ArchiveURL
	elseif url:match('//liveweb%.archive%.org/') then
		err_msg = cfg.err_msg_supl.liveweb;
	else
		path, timestamp, flag = url:match('//web%.archive%.org/([^%d]*)(%d+)([^/]*)/');	-- split out some of the URL parts for evaluation
		
		if not utilities.is_set (timestamp) or 14 ~= timestamp:len() then		-- path and flag optional, must have 14-digit timestamp here
			err_msg = cfg.err_msg_supl.timestamp;
			if '*' ~= flag then
				url=url:gsub ('(//web%.archive%.org/[^%d]*%d?%d?%d?%d?%d?%d?)[^/]*', '%1*', 1)	-- for preview, modify ts to be yearmo* max (0-6 digits plus splat)
			end
		elseif utilities.is_set (path) and 'web/' ~= path then					-- older archive URLs do not have the extra 'web/' path element
			err_msg = cfg.err_msg_supl.path;
		elseif utilities.is_set (flag) and not utilities.is_set (path) then		-- flag not allowed with the old form URL (without the 'web/' path element)
			err_msg = cfg.err_msg_supl.flag;
		elseif utilities.is_set (flag) and not flag:match ('%a%a_') then		-- flag if present must be two alpha characters and underscore (requires 'web/' path element)
			err_msg = cfg.err_msg_supl.flag;
		else
			return url, date;													-- return ArchiveURL and ArchiveDate
		end
	end
																				-- if here, something not right so
	table.insert( z.message_tail, { utilities.set_message ( 'err_archive_url', {err_msg}, true ) } );	-- add error message and
	if utilities.is_set (Frame:preprocess('{{REVISIONID}}')) then
		return '', '';															-- return empty strings for ArchiveURL and ArchiveDate
	else
		return url, date;														-- preview mode so return ArchiveURL and ArchiveDate
	end
end


--[[--------------------------< P L A C E _ C H E C K >--------------------------------------------------------

check |place=, |publication-place=, |location= to see if these params include digits.  This function added because
many editors misuse location to specify the in-source location (|page(s)= and |at= are supposed to do that)

returns the original parameter value without modification; added maint cat when parameter value contains digits

]]

local function place_check (param_val)
	if not utilities.is_set (param_val) then									-- parameter empty or omitted
		return param_val;														-- return that empty state
	end
	
	if mw.ustring.find (param_val, '%d') then									-- not empty, are there digits in the parameter value
		utilities.set_message ('maint_location');								-- yep, add maint cat
	end
	
	return param_val;															-- and done
end


--[[--------------------------< I S _ G E N E R I C _ T I T L E >----------------------------------------------

compares |title= value against list of known generic title patterns.  Returns true when pattern matches; nil else

the k/v pairs in 'generic_titles' each contain two tables, one for English and one for another 'local' language
Each of those tables contain another table that holds the string or pattern (whole title or title fragment) in
index [1].  index [2] is a Boolean that tells string.find() or mw.ustring.find() to do plain-text search (true)
or a pattern search (false).  The intent of all this complexity is to make these searches as fast as possible so
that we don't run out of processing time on very large articles.

]]

local function is_generic_title (title)
	title = mw.ustring.lower(title);											-- switch title to lower case
	for _, generic_title in ipairs (cfg.special_case_translation['generic_titles']) do 	-- spin through the list of known generic title fragments
		if title:find (generic_title['en'][1], 1, generic_title['en'][2]) then
			return true;														-- found English generic title so done
		elseif generic_title['local'] then										-- to keep work load down, generic_title['local'] should be nil except when there is a local version of the generic title
			if mw.ustring.find (title, generic_title['local'][1], 1, generic_title['local'][2]) then	-- mw.ustring() because might not be Latin script
				return true;													-- found local generic title so done
			end
		end
	end
end


--[[--------------------------< I S _ A R C H I V E D _ C O P Y >----------------------------------------------

compares |title= to 'Archived copy' (placeholder added by bots that can't find proper title); if matches, return true; nil else

]]

local function is_archived_copy (title)
	title = mw.ustring.lower(title);											-- switch title to lower case
	if title:find (cfg.special_case_translation.archived_copy.en) then			-- if title is 'Archived copy'
		return true;
	elseif cfg.special_case_translation.archived_copy['local'] then
		if mw.ustring.find (title, cfg.special_case_translation.archived_copy['local']) then	-- mw.ustring() because might not be Latin script
			return true;
		end
	end
end


--[[--------------------------< C I T A T I O N 0 >------------------------------------------------------------

This is the main function doing the majority of the citation formatting.

]]

local 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 

	-- Pick out the relevant fields from the arguments.  Different citation templates
	-- define different field names for the same underlying things.	

	local author_etal;
	local a	= {};																-- authors list from |lastn= / |firstn= pairs or |vauthors=
	local Authors;
	local NameListStyle = is_valid_parameter_value (A['NameListStyle'], A:ORIGIN('NameListStyle'), cfg.keywords_lists['name-list-style'], '');
	local Collaboration = A['Collaboration'];

	do																			-- to limit scope of selected
		local selected = select_author_editor_source (A['Vauthors'], A['Authors'], args, 'AuthorList');
		if 1 == selected then
			a, author_etal = extract_names (args, 'AuthorList');				-- fetch author list from |authorn= / |lastn= / |firstn=, |author-linkn=, and |author-maskn=
		elseif 2 == selected then
			NameListStyle = 'vanc';												-- override whatever |name-list-style= might be
			a, author_etal = parse_vauthors_veditors (args, args.vauthors, 'AuthorList');	-- fetch author list from |vauthors=, |author-linkn=, and |author-maskn=
		elseif 3 == selected then
			Authors = A['Authors'];												-- use content of |authors=
			if 'authors' == A:ORIGIN('Authors') then							-- but add a maint cat if the parameter is |authors=
				utilities.set_message ('maint_authors');						-- because use of this parameter is discouraged; what to do about the aliases is a TODO:
			end
		end
		if utilities.is_set (Collaboration) then
			author_etal = true;													-- so that |display-authors=etal not required
		end
	end

	local editor_etal;
	local e	= {};																-- editors list from |editor-lastn= / |editor-firstn= pairs or |veditors=

	do																			-- to limit scope of selected
		local selected = select_author_editor_source (A['Veditors'], nil, args, 'EditorList');	-- support for |editors= withdrawn
		if 1 == selected then
			e, editor_etal = extract_names (args, 'EditorList');				-- fetch editor list from |editorn= / |editor-lastn= / |editor-firstn=, |editor-linkn=, and |editor-maskn=
		elseif 2 == selected then
			NameListStyle = 'vanc';												-- override whatever |name-list-style= might be
			e, editor_etal = parse_vauthors_veditors (args, args.veditors, 'EditorList');	-- fetch editor list from |veditors=, |editor-linkn=, and |editor-maskn=
		end
	end
							
	local Chapter = A['Chapter'];												-- done here so that we have access to |contribution= from |chapter= aliases
	local Chapter_origin = A:ORIGIN ('Chapter');
	local Contribution;															-- because contribution is required for contributor(s)
		if 'contribution' == Chapter_origin then
			Contribution = Chapter;												-- get the name of the contribution
		end
	local c = {};																-- contributors list from |contributor-lastn= / contributor-firstn= pairs
	
	if utilities.in_array (config.CitationClass, {"book", "citation"}) and not utilities.is_set (A['Periodical']) then	-- |contributor= and |contribution= only supported in book cites
		c = extract_names (args, 'ContributorList');							-- fetch contributor list from |contributorn= / |contributor-lastn=, -firstn=, -linkn=, -maskn=
		
		if 0 < #c then
			if not utilities.is_set (Contribution) then							-- |contributor= requires |contribution=
				table.insert( z.message_tail, { utilities.set_message ( 'err_contributor_missing_required_param', 'contribution')});	-- add missing contribution error message
				c = {};															-- blank the contributors' table; it is used as a flag later
			end
			if 0 == #a then														-- |contributor= requires |author=
				table.insert( z.message_tail, { utilities.set_message ( 'err_contributor_missing_required_param', 'author')});	-- add missing author error message
				c = {};															-- blank the contributors' table; it is used as a flag later
			end
		end
	else																		-- if not a book cite
		if utilities.select_one (args, cfg.aliases['ContributorList-Last'], 'err_redundant_parameters', 1 ) then	-- are there contributor name list parameters?
			table.insert( z.message_tail, { utilities.set_message ( 'err_contributor_ignored')});	-- add contributor ignored error message
		end
		Contribution = nil;														-- unset
	end

	local Title = A['Title'];
	local TitleLink = A['TitleLink'];

	local auto_select = ''; -- default is auto
	local accept_link;
	TitleLink, accept_link = utilities.has_accept_as_written(TitleLink, true);	-- test for accept-this-as-written markup
	if (not accept_link) and utilities.in_array (TitleLink, {'none', 'pmc', 'doi'}) then -- check for special keywords
		auto_select = TitleLink;												-- remember selection for later
		TitleLink = '';															-- treat as if |title-link= would have been empty
	end

	TitleLink = link_title_ok (TitleLink, A:ORIGIN ('TitleLink'), Title, 'title');	-- check for wiki-markup in |title-link= or wiki-markup in |title= when |title-link= is set

	local Section = '';															-- {{cite map}} only; preset to empty string for concatenation if not used
	if 'map' == config.CitationClass and 'section' == Chapter_origin then
		Section = A['Chapter'];													-- get |section= from |chapter= alias list; |chapter= and the other aliases not supported in {{cite map}}
		Chapter = '';															-- unset for now; will be reset later from |map= if present
	end

	local Periodical = A['Periodical'];
	local Periodical_origin = '';
	if utilities.is_set (Periodical) then
		Periodical_origin = A:ORIGIN('Periodical');								-- get the name of the periodical parameter
		local i;
		Periodical, i = utilities.strip_apostrophe_markup (Periodical);			-- strip apostrophe markup so that metadata isn't contaminated 
		if i then																-- non-zero when markup was stripped so emit an error message
			table.insert( z.message_tail, {utilities.set_message ('err_apostrophe_markup', {Periodical_origin}, true)});
		end
	end

	if 'mailinglist' == config.CitationClass then								-- special case for {{cite mailing list}}
		if utilities.is_set (Periodical) and utilities.is_set (A ['MailingList']) then	-- both set emit an error
			table.insert( z.message_tail, {utilities.set_message ('err_redundant_parameters', {utilities.wrap_style ('parameter', Periodical_origin) .. ' and ' .. utilities.wrap_style ('parameter', 'mailinglist')}, true )});
		end

		Periodical = A ['MailingList'];											-- error or no, set Periodical to |mailinglist= value because this template is {{cite mailing list}}
		Periodical_origin = A:ORIGIN('MailingList');
	end

	local ScriptPeriodical = A['ScriptPeriodical'];

	-- web and news not tested for now because of 
	-- Wikipedia:Administrators%27_noticeboard#Is_there_a_semi-automated_tool_that_could_fix_these_annoying_"Cite_Web"_errors?
	if not (utilities.is_set (Periodical) or utilities.is_set (ScriptPeriodical)) then	-- 'periodical' templates require periodical parameter
	--	local p = {['journal'] = 'journal', ['magazine'] = 'magazine', ['news'] = 'newspaper', ['web'] = 'website'};	-- for error message
		local p = {['journal'] = 'journal', ['magazine'] = 'magazine'};			-- for error message
		if p[config.CitationClass]  then
			table.insert( z.message_tail, {utilities.set_message ('err_missing_periodical', {config.CitationClass, p[config.CitationClass]}, true)});
		end
	end
	
	local Volume;
	local ScriptPeriodical_origin = A:ORIGIN('ScriptPeriodical');
	if 'citation' == config.CitationClass then
		if utilities.is_set (Periodical) then
			if not utilities.in_array (Periodical_origin, {'website', 'mailinglist'}) then	-- {{citation}} does not render volume for these 'periodicals'
				Volume = A['Volume'];											-- but does for all other 'periodicals'
			end
		elseif utilities.is_set (ScriptPeriodical) then
			if 'script-website' ~= ScriptPeriodical_origin then					-- {{citation}} does not render volume for |script-website=
				Volume = A['Volume'];											-- but does for all other 'periodicals'
			end
		else
			Volume = A['Volume'];												-- and does for non-'periodical' cites
		end
	elseif utilities.in_array (config.CitationClass, cfg.templates_using_volume) then	-- render |volume= for cs1 according to the configuration settings
		Volume = A['Volume'];
	end	
	extra_text_in_vol_iss_check (Volume, A:ORIGIN ('Volume'), 'v');	

	local Issue;
	if 'citation' == config.CitationClass then
		if utilities.is_set (Periodical) and utilities.in_array (Periodical_origin, {'journal', 'magazine', 'newspaper', 'periodical', 'work'}) or	-- {{citation}} renders issue for these 'periodicals'
			utilities.is_set (ScriptPeriodical) and utilities.in_array (ScriptPeriodical_origin, {'script-journal', 'script-magazine', 'script-newspaper', 'script-periodical', 'script-work'}) then -- and these 'script-periodicals'
				Issue = hyphen_to_dash (A['Issue']);
		end
	elseif utilities.in_array (config.CitationClass, cfg.templates_using_issue) then	-- conference & map books do not support issue; {{citation}} listed here because included in settings table
		if not (utilities.in_array (config.CitationClass, {'conference', 'map', 'citation'}) and not (utilities.is_set (Periodical) or utilities.is_set (ScriptPeriodical))) then
			Issue = hyphen_to_dash (A['Issue']);
		end
	end
	extra_text_in_vol_iss_check (Issue, A:ORIGIN ('Issue'), 'i');	

	local Page;
	local Pages;
	local At;
	if not utilities.in_array (config.CitationClass, cfg.templates_not_using_page) then
		Page = A['Page'];
		Pages = hyphen_to_dash (A['Pages']);	
		At = A['At'];
	end

	local Edition = A['Edition'];
	local PublicationPlace = place_check (A['PublicationPlace'], A:ORIGIN('PublicationPlace'));
	local Place = place_check (A['Place'], A:ORIGIN('Place'));
	
	local PublisherName = A['PublisherName'];
	local PublisherName_origin = A:ORIGIN('PublisherName');
	if utilities.is_set (PublisherName) then
		local i = 0;
		PublisherName, i = utilities.strip_apostrophe_markup (PublisherName);	-- strip apostrophe markup so that metadata isn't contaminated; publisher is never italicized
		if i then																-- non-zero when markup was stripped so emit an error message
			table.insert( z.message_tail, {utilities.set_message ('err_apostrophe_markup', {PublisherName_origin}, true)});
		end
	end

	local Newsgroup = A['Newsgroup'];											-- TODO: strip apostrophe markup?
	local Newsgroup_origin = A:ORIGIN('Newsgroup');	

	if 'newsgroup' == config.CitationClass then
		if utilities.is_set (PublisherName) then								-- general use parameter |publisher= not allowed in cite newsgroup
			local error_text, error_state = utilities.set_message ('err_parameter_ignored', {PublisherName_origin}, true);
			if utilities.is_set (error_text) then
				table.insert( z.message_tail, {error_text, error_state} );
			end				
		end

		PublisherName = nil;													-- ensure that this parameter is unset for the time being; will be used again after COinS
	end

	local URL = A['URL']
	local UrlAccess = is_valid_parameter_value (A['UrlAccess'], A:ORIGIN('UrlAccess'), cfg.keywords_lists['url-access'], nil);
	
	if not utilities.is_set (URL) and utilities.is_set (UrlAccess) then
		UrlAccess = nil;
		table.insert( z.message_tail, { utilities.set_message ( 'err_param_access_requires_param', {'url'}, true ) } );
	end
	
	local ChapterURL = A['ChapterURL'];
	local ChapterUrlAccess = is_valid_parameter_value (A['ChapterUrlAccess'], A:ORIGIN('ChapterUrlAccess'), cfg.keywords_lists['url-access'], nil);
	if not utilities.is_set (ChapterURL) and utilities.is_set (ChapterUrlAccess) then
		ChapterUrlAccess = nil;
		table.insert( z.message_tail, { utilities.set_message ( 'err_param_access_requires_param', {A:ORIGIN('ChapterUrlAccess'):gsub ('%-access', '')}, true ) } );
	end

	local MapUrlAccess = is_valid_parameter_value (A['MapUrlAccess'], A:ORIGIN('MapUrlAccess'), cfg.keywords_lists['url-access'], nil);
	if not utilities.is_set (A['MapURL']) and utilities.is_set (MapUrlAccess) then
		MapUrlAccess = nil;
		table.insert( z.message_tail, { utilities.set_message ( 'err_param_access_requires_param', {'map-url'}, true ) } );
	end

	local this_page = mw.title.getCurrentTitle();								-- also used for COinS and for language
	local no_tracking_cats = is_valid_parameter_value (A['NoTracking'], A:ORIGIN('NoTracking'), cfg.keywords_lists['yes_true_y'], nil);

	-- 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 utilities.is_set (no_tracking_cats) then								-- ignore if we are already not going to categorize this page
		if utilities.in_array (this_page.nsText, cfg.uncategorized_namespaces) then
			no_tracking_cats = "true";											-- set no_tracking_cats
		end
		for _, v in ipairs (cfg.uncategorized_subpages) do						-- cycle through page name patterns
			if this_page.text:match (v) then									-- test page name against each pattern
				no_tracking_cats = "true";										-- set no_tracking_cats
				break;															-- bail out if one is found
			end
		end
	end
																				-- check for extra |page=, |pages= or |at= parameters. (also sheet and sheets while we're at it)
	utilities.select_one (args, {'page', 'p', 'pp', 'pages', 'at', 'sheet', 'sheets'}, 'err_redundant_parameters');	-- this is a dummy call simply to get the error message and category

	local coins_pages;
	
	Page, Pages, At, coins_pages = insource_loc_get (Page, A:ORIGIN('Page'), Pages, A:ORIGIN('Pages'), At);

	local NoPP = is_valid_parameter_value (A['NoPP'], A:ORIGIN('NoPP'), cfg.keywords_lists['yes_true_y'], nil);

	if utilities.is_set (PublicationPlace) and utilities.is_set (Place) then	-- both |publication-place= and |place= (|location=) allowed if different
		utilities.add_prop_cat ('location test');								-- add property cat to evaluate how often PublicationPlace and Place are used together
		if PublicationPlace == Place then
			Place = '';															-- unset; don't need both if they are the same
		end
	elseif not utilities.is_set (PublicationPlace) and utilities.is_set (Place) then	-- when only |place= (|location=) is set ...
		PublicationPlace = Place;												-- promote |place= (|location=) to |publication-place
	end

	if PublicationPlace == Place then Place = ''; end							-- don't need both if they are the same
	
	local URL_origin = A:ORIGIN('URL');											-- get name of parameter that holds URL
	local ChapterURL_origin = A:ORIGIN('ChapterURL');							-- get name of parameter that holds ChapterURL
	local ScriptChapter = A['ScriptChapter'];
	local ScriptChapter_origin = A:ORIGIN ('ScriptChapter');
	local Format = A['Format'];
	local ChapterFormat = A['ChapterFormat'];
	local TransChapter = A['TransChapter'];
	local TransChapter_origin = A:ORIGIN ('TransChapter');
	local TransTitle = A['TransTitle'];
	local ScriptTitle = A['ScriptTitle'];
	
	--[[
	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=

		|trans-title= maps to |trans-chapter= when |title= is re-mapped
		|url= maps to |chapter-url= when |title= is remapped
	
	All other combinations of |encyclopedia=, |title=, and |article= are not modified
	
	]]

	local Encyclopedia = A['Encyclopedia'];										-- used as a flag by this module and by ~/COinS

	if utilities.is_set (Encyclopedia) then										-- emit error message when Encyclopedia set but template is other than {{cite encyclopedia}} or {{citation}}
		if 'encyclopaedia' ~= config.CitationClass and 'citation' ~= config.CitationClass then
			table.insert (z.message_tail, {utilities.set_message ('err_parameter_ignored', {A:ORIGIN ('Encyclopedia')}, true)});
			Encyclopedia = nil;													-- unset because not supported by this template
		end
	end

	if ('encyclopaedia' == config.CitationClass) or ('citation' == config.CitationClass and utilities.is_set (Encyclopedia)) then
		if utilities.is_set (Periodical) and utilities.is_set (Encyclopedia) then	-- when both set emit an error
			table.insert (z.message_tail, {utilities.set_message ('err_redundant_parameters', {utilities.wrap_style ('parameter', A:ORIGIN ('Encyclopedia')) .. ' and ' .. utilities.wrap_style ('parameter', Periodical_origin)}, true )});
		end

		if utilities.is_set (Encyclopedia) then
			Periodical = Encyclopedia;											-- error or no, set Periodical to Encyclopedia; allow periodical without encyclopedia
			Periodical_origin = A:ORIGIN ('Encyclopedia');
		end

		if utilities.is_set (Periodical) then									-- Periodical is set when |encyclopedia= is set
			if utilities.is_set (Title) or utilities.is_set (ScriptTitle) then
				if not utilities.is_set (Chapter) then
					Chapter = Title;											-- |encyclopedia= and |title= are set so map |title= to |article= and |encyclopedia= to |title=
					ScriptChapter = ScriptTitle;
					ScriptChapter_origin = A:ORIGIN('ScriptTitle')
					TransChapter = TransTitle;
					ChapterURL = URL;
					ChapterURL_origin = URL_origin;

					ChapterUrlAccess = UrlAccess;

					if not utilities.is_set (ChapterURL) and utilities.is_set (TitleLink) then
						Chapter = utilities.make_wikilink (TitleLink, Chapter);
					end
					Title = Periodical;
					ChapterFormat = Format;
					Periodical = '';											-- redundant so unset
					TransTitle = '';
					URL = '';
					Format = '';
					TitleLink = '';
					ScriptTitle = '';
				end
			elseif utilities.is_set (Chapter) then								-- |title= not set
				Title = Periodical;												-- |encyclopedia= set and |article= set so map |encyclopedia= to |title=
				Periodical = '';												-- redundant so unset
			end
		end
	end

	-- special case for cite techreport.
	local ID = A['ID'];
	if (config.CitationClass == "techreport") then								-- special case for cite techreport
		if utilities.is_set (A['Number']) then									-- cite techreport uses 'number', which other citations alias to 'issue'
			if not utilities.is_set (ID) then									-- can we use ID for the "number"?
				ID = A['Number'];												-- yes, use it
			else																-- ID has a value so emit error message
				table.insert( z.message_tail, { utilities.set_message ('err_redundant_parameters', {utilities.wrap_style ('parameter', 'id') .. ' and ' .. utilities.wrap_style ('parameter', 'number')}, true )});
			end
		end	
	end

	-- Account for the oddity that is {{cite conference}}, before generation of COinS data.
	local ChapterLink -- = A['ChapterLink'];									-- deprecated as a parameter but still used internally by cite episode
	local Conference = A['Conference'];
	local BookTitle = A['BookTitle'];
	local TransTitle_origin = A:ORIGIN ('TransTitle');
	if 'conference' == config.CitationClass then
		if utilities.is_set (BookTitle) then
			Chapter = Title;
			Chapter_origin = 'title';
	--		ChapterLink = TitleLink;											-- |chapter-link= is deprecated
			ChapterURL = URL;
			ChapterUrlAccess = UrlAccess;
			ChapterURL_origin = URL_origin;
			URL_origin = '';
			ChapterFormat = Format;
			TransChapter = TransTitle;
			TransChapter_origin = TransTitle_origin;
			Title = BookTitle;
			Format = '';
	--		TitleLink = '';
			TransTitle = '';
			URL = '';
		end
	elseif 'speech' ~= config.CitationClass then
		Conference = '';														-- not cite conference or cite speech so make sure this is empty string
	end
	
	-- CS1/2 mode
	local Mode = is_valid_parameter_value (A['Mode'], A:ORIGIN('Mode'), cfg.keywords_lists['mode'], '');
	-- separator character and postscript
	local sepc, PostScript = set_style (Mode:lower(), A['PostScript'], config.CitationClass);
	-- controls capitalization of certain static text
	local use_lowercase = ( sepc == ',' );
	
	-- cite map oddities
	local Cartography = "";
	local Scale = "";
	local Sheet = A['Sheet'] or '';
	local Sheets = A['Sheets'] or '';
	if config.CitationClass == "map" then
		if utilities.is_set (Chapter) then
			table.insert( z.message_tail, { utilities.set_message ( 'err_redundant_parameters', {utilities.wrap_style ('parameter', 'map') .. ' and ' .. utilities.wrap_style ('parameter', Chapter_origin)}, true ) } );	-- add error message
		end
		Chapter = A['Map'];
		Chapter_origin = A:ORIGIN('Map');
		ChapterURL = A['MapURL'];
		ChapterURL_origin = A:ORIGIN('MapURL');
		TransChapter = A['TransMap'];
		ScriptChapter = A['ScriptMap']
		ScriptChapter_origin = A:ORIGIN('ScriptMap')

		ChapterUrlAccess = MapUrlAccess;
		ChapterFormat = A['MapFormat'];

		Cartography = A['Cartography'];
		if utilities.is_set ( Cartography ) then
			Cartography = sepc .. " " .. wrap_msg ('cartography', Cartography, use_lowercase);
		end		
		Scale = A['Scale'];
		if utilities.is_set ( Scale ) then
			Scale = sepc .. " " .. Scale;
		end
	end

	-- Account for the oddities that are {{cite episode}} and {{cite serial}}, before generation of COinS data.
	local Series = A['Series'];
	if 'episode' == config.CitationClass or 'serial' == config.CitationClass then
		local SeriesLink = A['SeriesLink'];

		SeriesLink = link_title_ok (SeriesLink, A:ORIGIN ('SeriesLink'), Series, 'series');	-- check for wiki-markup in |series-link= or wiki-markup in |series= when |series-link= is set

		local Network = A['Network'];
		local Station = A['Station'];
		local s, n = {}, {};
																				-- do common parameters first
		if utilities.is_set (Network) then table.insert(n, Network); end
		if utilities.is_set (Station) then table.insert(n, Station); end
		ID = table.concat(n, sepc .. ' ');
		
		if 'episode' == config.CitationClass then								-- handle the oddities that are strictly {{cite episode}}
			local Season = A['Season'];
			local SeriesNumber = A['SeriesNumber'];

			if utilities.is_set (Season) and utilities.is_set (SeriesNumber) then	-- these are mutually exclusive so if both are set
				table.insert( z.message_tail, { utilities.set_message ( 'err_redundant_parameters', {utilities.wrap_style ('parameter', 'season') .. ' and ' .. utilities.wrap_style ('parameter', 'seriesno')}, true ) } );		-- add error message
				SeriesNumber = '';												-- unset; prefer |season= over |seriesno=
			end
																				-- assemble a table of parts concatenated later into Series
			if utilities.is_set (Season) then table.insert(s, wrap_msg ('season', Season, use_lowercase)); end
			if utilities.is_set (SeriesNumber) then table.insert(s, wrap_msg ('seriesnum', SeriesNumber, use_lowercase)); end
			if utilities.is_set (Issue) then table.insert(s, wrap_msg ('episode', Issue, use_lowercase)); end
			Issue = '';															-- unset because this is not a unique parameter
	
			Chapter = Title;													-- promote title parameters to chapter
			ScriptChapter = ScriptTitle;
			ScriptChapter_origin = A:ORIGIN('ScriptTitle');
			ChapterLink = TitleLink;											-- alias |episode-link=
			TransChapter = TransTitle;
			ChapterURL = URL;
			ChapterUrlAccess = UrlAccess;
			ChapterURL_origin = URL_origin;
			
			Title = Series;														-- promote series to title
			TitleLink = SeriesLink;
			Series = table.concat(s, sepc .. ' ');								-- this is concatenation of season, seriesno, episode number

			if utilities.is_set (ChapterLink) and not utilities.is_set (ChapterURL) then	-- link but not URL
				Chapter = utilities.make_wikilink (ChapterLink, Chapter);
			elseif utilities.is_set (ChapterLink) and utilities.is_set (ChapterURL) then	-- if both are set, URL links episode;
				Series = utilities.make_wikilink (ChapterLink, Series);
			end
			URL = '';															-- unset
			TransTitle = '';
			ScriptTitle = '';
			
		else																	-- now oddities that are cite serial
			Issue = '';															-- unset because this parameter no longer supported by the citation/core version of cite serial
			Chapter = A['Episode'];												-- TODO: make |episode= available to cite episode someday?
			if utilities.is_set (Series) and utilities.is_set (SeriesLink) then
				Series = utilities.make_wikilink (SeriesLink, Series);
			end
			Series = utilities.wrap_style ('italic-title', Series);				-- series is italicized
		end	
	end
	-- end of {{cite episode}} stuff

	-- handle type parameter for those CS1 citations that have default values
	local TitleType = A['TitleType'];
	local Degree = A['Degree'];
	if utilities.in_array (config.CitationClass, {"AV-media-notes", "interview", "mailinglist", "map", "podcast", "pressrelease", "report", "techreport", "thesis"}) then
		TitleType = set_titletype (config.CitationClass, TitleType);
		if utilities.is_set (Degree) and "Thesis" == TitleType then				-- special case for cite thesis
			TitleType = Degree .. ' ' .. cfg.title_types ['thesis']:lower();
		end
	end

	if utilities.is_set (TitleType) then										-- if type parameter is specified
		TitleType = utilities.substitute ( cfg.messages['type'], TitleType);	-- display it in parentheses
	-- TODO: Hack on TitleType to fix bunched parentheses problem
	end

	-- legacy: promote PublicationDate to Date if neither Date nor Year are set.
	local Date = A['Date'];
 	local Date_origin;															-- to hold the name of parameter promoted to Date; required for date error messaging
	local PublicationDate = A['PublicationDate'];
	local Year = A['Year'];

	if not utilities.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 not utilities.is_set (Date) and utilities.is_set (PublicationDate) then	-- use PublicationDate when |date= and |year= are not set
			Date = PublicationDate;												-- promote PublicationDate to Date
			Date = vi_formatdate(PublicationDate);			-- promote PublicationDate to Date
			PublicationDate = '';												-- unset, no longer needed
			Date_origin = A:ORIGIN('PublicationDate');							-- save the name of the promoted parameter
		else
			Date_origin = A:ORIGIN('Year');										-- save the name of the promoted parameter
		end
		if PublicationDate and #PublicationDate > 0 then PublicationDate = vi_formatdate(PublicationDate) end
	else
		Date_origin = A:ORIGIN('Date');											-- not a promotion; name required for error messaging
	end

	if PublicationDate == Date then PublicationDate = ''; end					-- if PublicationDate is same as Date, don't display in rendered citation
	if Date and #Date > 0 then Date = vi_formatdate(Date) end

	--[[
	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
	]]

	local DF = is_valid_parameter_value (A['DF'], A:ORIGIN('DF'), cfg.keywords_lists['df'], '');
	if not utilities.is_set (DF) then
		DF = cfg.global_df;														-- local |df= if present overrides global df set by {{use xxx date}} template
	end

	local ArchiveURL;
	local ArchiveDate;
	local ArchiveFormat = A['ArchiveFormat'];

	ArchiveURL, ArchiveDate = archive_url_check (A['ArchiveURL'], A['ArchiveDate'])
	ArchiveFormat = style_format (ArchiveFormat, ArchiveURL, 'archive-format', 'archive-url');
	
	ArchiveURL, ArchiveDate = is_unique_archive_url (ArchiveURL, URL, ChapterURL, A:ORIGIN('ArchiveURL'), ArchiveDate);		-- add error message when URL or ChapterURL == ArchiveURL

	
	local AccessDate = A['AccessDate'];
	local LayDate = A['LayDate'];
	local COinS_date = {};														-- holds date info extracted from |date= for the COinS metadata by Module:Date verification
	local DoiBroken = A['DoiBroken'];
	local Embargo = A['Embargo'];
	local anchor_year;															-- used in the CITEREF identifier
	do	-- create defined block to contain local variables error_message, date_parameters_list, mismatch
		local error_message = '';
																				-- AirDate has been promoted to Date so not necessary to check it
		local date_parameters_list = {
			['access-date'] = {val = AccessDate, name = A:ORIGIN ('AccessDate')},
			['archive-date'] = {val = ArchiveDate, name = A:ORIGIN ('ArchiveDate')},
			['date'] = {val = Date, name = Date_origin},
			['doi-broken-date'] = {val = DoiBroken, name = A:ORIGIN ('DoiBroken')},
			['pmc-embargo-date'] = {val = Embargo, name = A:ORIGIN ('Embargo')},
			['lay-date'] = {val = LayDate, name = A:ORIGIN ('LayDate')},
			['publication-date'] = {val = PublicationDate, name = A:ORIGIN ('PublicationDate')},
			['year'] = {val = Year, name = A:ORIGIN ('Year')},
			};

		local error_list = {};
		anchor_year, Embargo = validation.dates(date_parameters_list, COinS_date, error_list);

-- start temporary Julian / Gregorian calendar uncertainty categorization
		if COinS_date.inter_cal_cat then
			utilities.add_prop_cat ('jul_greg_uncertainty');
		end
-- end temporary Julian / Gregorian calendar uncertainty categorization

		if utilities.is_set (Year) and utilities.is_set (Date) then				-- both |date= and |year= not normally needed; 
			validation.year_date_check (Year, A:ORIGIN ('Year'), Date, A:ORIGIN ('Date'), error_list);
		end
		
		if 0 == #error_list then												-- error free dates only; 0 when error_list is empty
			local modified = false;												-- flag
			
			if validation.edtf_transform (date_parameters_list) then			-- edtf dates to MOS compliant format
				modified = true;
			end

			if utilities.is_set (DF) then										-- if we need to reformat dates
				modified = validation.reformat_dates (date_parameters_list, DF);	-- reformat to DF format, use long month names if appropriate
			end

			if true == validation.date_hyphen_to_dash (date_parameters_list) then	-- convert hyphens to dashes where appropriate
				modified = true;
				utilities.set_message ('maint_date_format');					-- hyphens were converted so add maint category
			end
			
	-- for those wikis that can and want to have English date names translated to the local language,
	-- uncomment the next three lines.  Not supported by en.wiki (for obvious reasons)
	-- set validation.date_name_xlate() second argument to true to translate English digits to local digits (will translate ymd dates)
	--		if validation.date_name_xlate (date_parameters_list, false) then
	--			modified = true;
	--		end

			if modified then													-- if the date_parameters_list values were modified
				AccessDate = date_parameters_list['access-date'].val;			-- overwrite date holding parameters with modified values
				ArchiveDate = date_parameters_list['archive-date'].val;
				Date = date_parameters_list['date'].val;
				DoiBroken = date_parameters_list['doi-broken-date'].val;
				LayDate = date_parameters_list['lay-date'].val;
				PublicationDate = date_parameters_list['publication-date'].val;
			end
		else
			table.insert (z.message_tail, {utilities.set_message ('err_bad_date', {utilities.make_sep_list (#error_list, error_list)}, true)});	-- add this error message
		end
	end	-- end of do

	local ID_list = {};															-- sequence table of rendered identifiers
	local ID_list_coins = {};													-- table of identifiers and their values from args; key is same as cfg.id_handlers's key
	local Class = A['Class'];													-- arxiv class identifier
	
	local ID_support = {
		{A['ASINTLD'], 'ASIN', 'err_asintld_missing_asin', A:ORIGIN ('ASINTLD')},				
		{DoiBroken, 'DOI', 'err_doibroken_missing_doi', A:ORIGIN ('DoiBroken')},
		{Embargo, 'PMC', 'err_embargo_missing_pmc', A:ORIGIN ('Embargo')},
		}

	ID_list, ID_list_coins = identifiers.identifier_lists_get (args, {DoiBroken = DoiBroken, ASINTLD = A['ASINTLD'], Embargo = Embargo, Class = Class}, ID_support);

	-- Account for the oddities that are {{cite arxiv}}, {{cite biorxiv}}, {{cite citeseerx}}, {{cite ssrn}}, before generation of COinS data.
	if utilities.in_array (config.CitationClass, whitelist.preprint_template_list) then
		if not utilities.is_set (ID_list_coins[config.CitationClass:upper()]) then 	-- |arxiv= or |eprint= required for cite arxiv; |biorxiv= & |citeseerx= required for their templates
			table.insert (z.message_tail, {utilities.set_message ('err_' .. config.CitationClass .. '_missing', {}, true)});	-- add error message
		end

		Periodical = ({['arxiv'] = 'arXiv', ['biorxiv'] = 'bioRxiv', ['citeseerx'] = 'CiteSeerX', ['ssrn'] = 'Social Science Research Network'})[config.CitationClass];
	end

	-- Link the title of the work if no |url= was provided, but we have a |pmc= or a |doi= with |doi-access=free

	if config.CitationClass == "journal" and not utilities.is_set (URL) and not utilities.is_set (TitleLink) and not utilities.in_array (cfg.keywords_xlate[Title], {'off', 'none'}) then -- TODO: remove 'none' once existing citations have been switched to 'off', so 'none' can be used as token for "no title" instead
		if 'none' ~= cfg.keywords_xlate[auto_select] then						-- if auto-linking not disabled
 	 		if identifiers.auto_link_urls[auto_select] then						-- manual selection
		 		URL = identifiers.auto_link_urls[auto_select];					-- set URL to be the same as identifier's external link
 				URL_origin = cfg.id_handlers[auto_select:upper()].parameters[1];	-- set URL_origin to parameter name for use in error message if citation is missing a |title=
			elseif identifiers.auto_link_urls['pmc'] then						-- auto-select PMC
				URL = identifiers.auto_link_urls['pmc'];						-- set URL to be the same as the PMC external link if not embargoed
				URL_origin = cfg.id_handlers['PMC'].parameters[1];				-- set URL_origin to parameter name for use in error message if citation is missing a |title=
			elseif identifiers.auto_link_urls['doi'] then						-- auto-select DOI
				URL = identifiers.auto_link_urls['doi'];
				URL_origin = cfg.id_handlers['DOI'].parameters[1];
			end
 	 	end

		if utilities.is_set (URL) and utilities.is_set (AccessDate) then		-- access date requires |url=; identifier-created URL is not |url=
			table.insert( z.message_tail, { utilities.set_message ( 'err_accessdate_missing_url', {}, true ) } );	-- add an error message
			AccessDate = '';													-- unset
		end
	end

	-- At this point fields may be nil if they weren't specified in the template use.  We can use that fact.
	-- Test if citation has no title
	if	not utilities.is_set (Title) and not utilities.is_set (TransTitle) and not utilities.is_set (ScriptTitle) then	-- has special case for cite episode
		table.insert( z.message_tail, { utilities.set_message ( 'err_citation_missing_title', {'episode' == config.CitationClass and 'series' or 'title'}, true ) } );
	end

	if utilities.in_array (cfg.keywords_xlate[Title], {'off', 'none'}) and
			utilities.in_array (config.CitationClass, {'journal', 'citation'}) and
			(utilities.is_set (Periodical) or utilities.is_set (ScriptPeriodical)) and
			('journal' == Periodical_origin or 'script-journal' == ScriptPeriodical_origin) then	-- special case for journal cites
				Title = '';														-- set title to empty string
				utilities.set_message ('maint_untitled');						-- add maint cat
	end

	check_for_url ({															-- add error message when any of these parameters hold a URL
		['title'] = Title,
		[A:ORIGIN('Chapter')] = Chapter,
		[Periodical_origin] = Periodical,
		[PublisherName_origin] = PublisherName
		});

	-- COinS metadata (see <http://ocoins.info/>) for automated parsing of citation information.
	-- handle the oddity that is cite encyclopedia and {{citation |encyclopedia=something}}. Here we presume that
	-- when Periodical, Title, and Chapter are all set, then Periodical is the book (encyclopedia) title, Title
	-- is the article title, and Chapter is a section within the article.  So, we remap 
	
	local coins_chapter = Chapter;												-- default assuming that remapping not required
	local coins_title = Title;													-- et tu
	if 'encyclopaedia' == config.CitationClass or ('citation' == config.CitationClass and utilities.is_set (Encyclopedia)) then
		if utilities.is_set (Chapter) and utilities.is_set (Title) and utilities.is_set (Periodical) then		-- if all are used then
			coins_chapter = Title;												-- remap
			coins_title = Periodical;
		end
	end
	local coins_author = a;														-- default for coins rft.au 
	if 0 < #c then																-- but if contributor list
		coins_author = c;														-- use that instead
	end
	
	local QuotePage = A['QuotePage'];
	local QuotePages = hyphen_to_dash (A['QuotePages']);

	-- this is the function call to COinS()
	local OCinSoutput = metadata.COinS({
		['Periodical'] = utilities.strip_apostrophe_markup (Periodical),		-- no markup in the metadata
		['Encyclopedia'] = Encyclopedia,										-- just a flag; content ignored by ~/COinS
		['Chapter'] = metadata.make_coins_title (coins_chapter, ScriptChapter),	-- Chapter and ScriptChapter stripped of bold / italic wiki-markup
		['Degree'] = Degree;													-- cite thesis only
		['Title'] = metadata.make_coins_title (coins_title, ScriptTitle),		-- Title and ScriptTitle stripped of bold / italic wiki-markup
		['PublicationPlace'] = PublicationPlace,
		['Date'] = COinS_date.rftdate,											-- COinS_date has correctly formatted date if Date is valid;
		['Season'] = COinS_date.rftssn,
		['Quarter'] = COinS_date.rftquarter,
		['Chron'] =  COinS_date.rftchron or (not COinS_date.rftdate and Date) or '',	-- chron but if not set and invalid date format use Date; keep this last bit?
		['Series'] = Series,
		['Volume'] = Volume,
		['Issue'] = Issue,
		['Pages'] = coins_pages or metadata.get_coins_pages (first_set ({Sheet, Sheets, Page, Pages, At, QuotePage, QuotePages}, 7)),	-- pages stripped of external links
		['Edition'] = Edition,
		['PublisherName'] = PublisherName or Newsgroup,							-- any apostrophe markup already removed from PublisherName
		['URL'] = first_set ({ChapterURL, URL}, 2),
		['Authors'] = coins_author,
		['ID_list'] = ID_list_coins,
		['RawPage'] = this_page.prefixedText,
	}, config.CitationClass);

	-- Account for the oddities that are {{cite arxiv}}, {{cite biorxiv}}, {{cite citeseerx}}, and {{cite ssrn}} AFTER generation of COinS data.
	if utilities.in_array (config.CitationClass, whitelist.preprint_template_list) then	-- we have set rft.jtitle in COinS to arXiv, bioRxiv, CiteSeerX, or ssrn now unset so it isn't displayed
		Periodical = '';														-- periodical not allowed in these templates; if article has been published, use cite journal
	end

	-- special case for cite newsgroup.  Do this after COinS because we are modifying Publishername to include some static text
	if 'newsgroup' == config.CitationClass and utilities.is_set (Newsgroup) then
		PublisherName = utilities.substitute (cfg.messages['newsgroup'], external_link( 'news:' .. Newsgroup, Newsgroup, Newsgroup_origin, nil ));
	end

	local Editors;
	local EditorCount;															-- used only for choosing {ed.) or (eds.) annotation at end of editor name-list
	local Contributors;															-- assembled contributors name list
	local contributor_etal;
	local Translators;															-- assembled translators name list
	local translator_etal;
	local t = {};																-- translators list from |translator-lastn= / translator-firstn= pairs
	t = extract_names (args, 'TranslatorList');									-- fetch translator list from |translatorn= / |translator-lastn=, -firstn=, -linkn=, -maskn=
	local Interviewers;															
	local interviewers_list = {};					
	interviewers_list = extract_names (args, 'InterviewerList');				-- process preferred interviewers parameters
	local interviewer_etal;
	
	-- 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.
	do
		local last_first_list;
		local control = { 
			format = NameListStyle,												-- empty string or 'vanc'
			maximum = nil,														-- as if display-authors or display-editors not set
			mode = Mode
		};

		do																		-- do editor name list first because the now unsupported coauthors used to modify control table
			control.maximum , editor_etal = get_display_names (A['DisplayEditors'], #e, 'editors', editor_etal, A:ORIGIN ('DisplayEditors'));
			Editors, EditorCount = list_people (control, e, editor_etal);

			if 1 == EditorCount and (true == editor_etal or 1 < #e) then		-- only one editor displayed but includes etal then 
				EditorCount = 2;												-- spoof to display (eds.) annotation
			end
		end
		do																		-- now do interviewers
			control.maximum, interviewer_etal = get_display_names (A['DisplayInterviewers'], #interviewers_list, 'interviewers', interviewer_etal, A:ORIGIN ('DisplayInterviewers'));
			Interviewers = list_people (control, interviewers_list, interviewer_etal);
		end
		do																		-- now do translators
			control.maximum, translator_etal = get_display_names (A['DisplayTranslators'], #t, 'translators', translator_etal, A:ORIGIN ('DisplayTranslators'));
			Translators = list_people (control, t, translator_etal);
		end
		do																		-- now do contributors
			control.maximum, contributor_etal = get_display_names (A['DisplayContributors'], #c, 'contributors', contributor_etal, A:ORIGIN ('DisplayContributors'));
			Contributors = list_people (control, c, contributor_etal);
		end
		do																		-- now do authors
			control.maximum, author_etal = get_display_names (A['DisplayAuthors'], #a, 'authors', author_etal, A:ORIGIN ('DisplayAuthors'));

			last_first_list = list_people (control, a, author_etal);

			if utilities.is_set (Authors) then
				Authors, author_etal = name_has_etal (Authors, author_etal, false, 'authors');	-- find and remove variations on et al.
				if author_etal then
					Authors = Authors .. ' ' .. cfg.messages['et al'];			-- add et al. to authors parameter
				end
			else
				Authors = last_first_list;										-- either an author name list or an empty string
			end
		end																		-- end of do
	
		if utilities.is_set (Authors) and utilities.is_set (Collaboration) then
			Authors = Authors .. ' (' .. Collaboration .. ')';					-- add collaboration after et al.
		end

	end

	local ConferenceFormat = A['ConferenceFormat'];
	local ConferenceURL = A['ConferenceURL'];
	ConferenceFormat = style_format (ConferenceFormat, ConferenceURL, 'conference-format', 'conference-url');
	Format = style_format (Format, URL, 'format', 'url');

	-- special case for chapter format so no error message or cat when chapter not supported
	if not (utilities.in_array (config.CitationClass, {'web', 'news', 'journal', 'magazine', 'pressrelease', 'podcast', 'newsgroup', 'arxiv', 'biorxiv', 'citeseerx', 'ssrn'}) or
		('citation' == config.CitationClass and (utilities.is_set (Periodical) or utilities.is_set (ScriptPeriodical)) and not utilities.is_set (Encyclopedia))) then
			ChapterFormat = style_format (ChapterFormat, ChapterURL, 'chapter-format', 'chapter-url');
	end

	if not utilities.is_set (URL) then
		if utilities.in_array (config.CitationClass, {"web", "podcast", "mailinglist"}) or		-- |url= required for cite web, cite podcast, and cite mailinglist
			('citation' == config.CitationClass and ('website' == Periodical_origin or 'script-website' == ScriptPeriodical_origin)) then	-- and required for {{citation}} with |website= or |script-website=
				table.insert( z.message_tail, { utilities.set_message ( 'err_cite_web_url', {}, true ) } );
		end
		
		-- do we have |accessdate= without either |url= or |chapter-url=?
		if utilities.is_set (AccessDate) and not utilities.is_set (ChapterURL) then		-- ChapterURL may be set when URL is not set;
			table.insert( z.message_tail, { utilities.set_message ( 'err_accessdate_missing_url', {}, true ) } );
			AccessDate = '';
		end
	end

	local UrlStatus = is_valid_parameter_value (A['UrlStatus'], A:ORIGIN('UrlStatus'), cfg.keywords_lists['url-status'], '');
	local OriginalURL
	local OriginalURL_origin
	local OriginalFormat
	local OriginalAccess;
	UrlStatus = UrlStatus:lower();												-- used later when assembling archived text
	if utilities.is_set ( ArchiveURL ) then
		if utilities.is_set (ChapterURL) then 									-- if chapter-url= is set apply archive url to it
			OriginalURL = ChapterURL;											-- save copy of source chapter's url for archive text
			OriginalURL_origin = ChapterURL_origin;								-- name of |chapter-url= parameter for error messages
			OriginalFormat = ChapterFormat;										-- and original |chapter-format=

			if 'live' ~= UrlStatus then
				ChapterURL = ArchiveURL											-- swap-in the archive's URL
				ChapterURL_origin = A:ORIGIN('ArchiveURL')						-- name of |archive-url= parameter for error messages
				ChapterFormat = ArchiveFormat or '';							-- swap in archive's format
				ChapterUrlAccess = nil;											-- restricted access levels do not make sense for archived URLs
			end
		elseif utilities.is_set (URL) then
			OriginalURL = URL;													-- save copy of original source URL
			OriginalURL_origin = URL_origin;									-- name of URL parameter for error messages
			OriginalFormat = Format; 											-- and original |format=
			OriginalAccess = UrlAccess;

			if 'live' ~= UrlStatus then											-- if URL set then |archive-url= applies to it
				URL = ArchiveURL												-- swap-in the archive's URL
				URL_origin = A:ORIGIN('ArchiveURL')								-- name of archive URL parameter for error messages
				Format = ArchiveFormat or '';									-- swap in archive's format
				UrlAccess = nil;												-- restricted access levels do not make sense for archived URLs
			end
 		end
	end

	if utilities.in_array (config.CitationClass, {'web', 'news', 'journal', 'magazine', 'pressrelease', 'podcast', 'newsgroup', 'arxiv', 'biorxiv', 'citeseerx', 'ssrn'}) or	-- if any of the 'periodical' cites except encyclopedia
		('citation' == config.CitationClass and (utilities.is_set (Periodical) or utilities.is_set (ScriptPeriodical)) and not utilities.is_set (Encyclopedia)) then
			local chap_param;
			if utilities.is_set (Chapter) then									-- get a parameter name from one of these chapter related meta-parameters
				chap_param = A:ORIGIN ('Chapter')
			elseif utilities.is_set (TransChapter) then
				chap_param = A:ORIGIN ('TransChapter')
			elseif utilities.is_set (ChapterURL) then
				chap_param = A:ORIGIN ('ChapterURL')
			elseif utilities.is_set (ScriptChapter) then
				chap_param = ScriptChapter_origin;
			else utilities.is_set (ChapterFormat)
				chap_param = A:ORIGIN ('ChapterFormat')
			end

			if utilities.is_set (chap_param) then								-- if we found one
				table.insert( z.message_tail, { utilities.set_message ( 'err_chapter_ignored', {chap_param}, true ) } );	-- add error message
				Chapter = '';													-- and set them to empty string to be safe with concatenation
				TransChapter = '';
				ChapterURL = '';
				ScriptChapter = '';
				ChapterFormat = '';
			end
	else																		-- otherwise, format chapter / article title
		local no_quotes = false;												-- default assume that we will be quoting the chapter parameter value
		if utilities.is_set (Contribution) and 0 < #c then						-- if this is a contribution with contributor(s)
			if utilities.in_array (Contribution:lower(), cfg.keywords_lists.contribution) then	-- and a generic contribution title
				no_quotes = true;												-- then render it unquoted
			end
		end

		Chapter = format_chapter_title (ScriptChapter, ScriptChapter_origin, Chapter, Chapter_origin, TransChapter, TransChapter_origin, ChapterURL, ChapterURL_origin, no_quotes, ChapterUrlAccess);		-- Contribution is also in Chapter
		if utilities.is_set (Chapter) then
			Chapter = Chapter .. ChapterFormat ;
			if 'map' == config.CitationClass and utilities.is_set (TitleType) then
				Chapter = Chapter .. ' ' .. TitleType;							-- map annotation here; not after title
			end
			Chapter = Chapter .. sepc .. ' ';
		elseif utilities.is_set (ChapterFormat) then							-- |chapter= not set but |chapter-format= is so ...
			Chapter = ChapterFormat .. sepc .. ' ';								-- ... ChapterFormat has error message, we want to see it
		end
	end

	-- Format main title
	local plain_title = false;
	local accept_title;
	Title, accept_title = utilities.has_accept_as_written (Title, true);		-- remove accept-this-as-written markup when it wraps all of <Title>
	if accept_title and ('' == Title) then										-- only support forced empty for now "(())"
		Title = cfg.messages['notitle'];										-- replace by predefined "No title" message
			-- TODO: utilities.set_message ( 'err_redundant_parameters', ...);	-- issue proper error message instead of muting	 
			ScriptTitle = '';													-- just mute for now	 
			TransTitle = '';													-- just mute for now
 		plain_title = true;														-- suppress text decoration for descriptive title
		utilities.set_message ('maint_untitled');								-- add maint cat
	end

	if not accept_title then -- <Title> not wrapped in accept-as-written markup
		if '...' == Title:sub (-3) then											-- if ellipsis is the last three characters of |title=
			Title = Title:gsub ('(%.%.%.)%.+$', '%1');							-- limit the number of dots to three
		elseif not mw.ustring.find (Title, '%.%s*%a%.$') and					-- end of title is not a 'dot-(optional space-)letter-dot' initialism ...
			not mw.ustring.find (Title, '%s+%a%.$') then						-- ...and not a 'space-letter-dot' initial (''Allium canadense'' L.)
				Title = mw.ustring.gsub(Title, '%' .. sepc .. '$', '');			-- remove any trailing separator character; sepc and ms.ustring() here for languages that use multibyte separator characters
		end

		if utilities.is_set (ArchiveURL) and is_archived_copy (Title) then
			utilities.set_message ('maint_archived_copy');						-- add maintenance category before we modify the content of Title
		end

		if is_generic_title (Title) then
			table.insert (z.message_tail, {utilities.set_message ( 'err_generic_title', {}, true ) } );	-- set an error message
		end
	end

	if (not plain_title) and (utilities.in_array (config.CitationClass, {'web', 'news', 'journal', 'magazine', 'pressrelease', 'podcast', 'newsgroup', 'mailinglist', 'interview', 'arxiv', 'biorxiv', 'citeseerx', 'ssrn'}) or
		('citation' == config.CitationClass and (utilities.is_set (Periodical) or utilities.is_set (ScriptPeriodical)) and not utilities.is_set (Encyclopedia)) or
		('map' == config.CitationClass and (utilities.is_set (Periodical) or utilities.is_set (ScriptPeriodical)))) then		-- special case for cite map when the map is in a periodical treat as an article
			Title = kern_quotes (Title);										-- if necessary, separate title's leading and trailing quote marks from module provided quote marks
			Title = utilities.wrap_style ('quoted-title', Title);
			Title = script_concatenate (Title, ScriptTitle, 'script-title');	-- <bdi> tags, lang attribute, categorization, etc.; must be done after title is wrapped
			TransTitle = utilities.wrap_style ('trans-quoted-title', TransTitle );
	elseif plain_title or ('report' == config.CitationClass) then								-- no styling for cite report and descriptive titles (otherwise same as above)
		Title = script_concatenate (Title, ScriptTitle, 'script-title');		-- <bdi> tags, lang attribute, categorization, etc.; must be done after title is wrapped
		TransTitle = utilities.wrap_style ('trans-quoted-title', TransTitle );				-- for cite report, use this form for trans-title
	else
		Title = utilities.wrap_style ('italic-title', Title);
		Title = script_concatenate (Title, ScriptTitle, 'script-title');		-- <bdi> tags, lang attribute, categorization, etc.; must be done after title is wrapped
		TransTitle = utilities.wrap_style ('trans-italic-title', TransTitle);
	end

	local TransError = "";
	if utilities.is_set (TransTitle) then
		if utilities.is_set (Title) then
			TransTitle = " " .. TransTitle;
		else
			TransError = " " .. utilities.set_message ( 'err_trans_missing_title', {'title'} );
		end
	end

	if utilities.is_set (Title) then											-- TODO: is this the right place to be making Wikisource URLs?
		if utilities.is_set (TitleLink) and utilities.is_set (URL) then
			table.insert( z.message_tail, { utilities.set_message ( 'err_wikilink_in_url', {}, true ) } );	-- set an error message because we can't have both
			TitleLink = '';														-- unset
		end
	
		if not utilities.is_set (TitleLink) and utilities.is_set (URL) then
			Title = external_link (URL, Title, URL_origin, UrlAccess) .. TransTitle .. TransError .. Format;
			URL = '';															-- unset these because no longer needed
			Format = "";
		elseif utilities.is_set (TitleLink) and not utilities.is_set (URL) then
			local ws_url;
			ws_url = wikisource_url_make (TitleLink);							-- ignore ws_label return; not used here
			if ws_url then
				Title = external_link (ws_url, Title .. '&nbsp;', 'ws link in title-link');	-- space char after Title to move icon away from italic text; TODO: a better way to do this?
				Title = utilities.substitute (cfg.presentation['interwiki-icon'], {cfg.presentation['class-wikisource'], TitleLink, Title});				
				Title = Title .. TransTitle .. TransError;
			else
				Title = utilities.make_wikilink (TitleLink, Title) .. TransTitle .. TransError;
			end
		else
			local ws_url, ws_label, L;											-- Title has italic or quote markup by the time we get here which causes is_wikilink() to return 0 (not a wikilink)
			ws_url, ws_label, L = wikisource_url_make (Title:gsub('^[\'"]*(.-)[\'"]*$', '%1'));	-- make ws URL from |title= interwiki link (strip italic or quote markup); link portion L becomes tooltip label
			if ws_url then
				Title = Title:gsub ('%b[]', ws_label);							-- replace interwiki link with ws_label to retain markup
				Title = external_link (ws_url, Title .. '&nbsp;', 'ws link in title');	-- space char after Title to move icon away from italic text; TODO: a better way to do this?
				Title = utilities.substitute (cfg.presentation['interwiki-icon'], {cfg.presentation['class-wikisource'], L, Title});				
				Title = Title .. TransTitle .. TransError;
			else
				Title = Title .. TransTitle .. TransError;
			end
		end
	else
		Title = TransTitle .. TransError;
	end

	if utilities.is_set (Place) then
		Place = " " .. wrap_msg ('written', Place, use_lowercase) .. sepc .. " ";
	end

	local ConferenceURL_origin = A:ORIGIN('ConferenceURL');						-- get name of parameter that holds ConferenceURL
	if utilities.is_set (Conference) then
		if utilities.is_set (ConferenceURL) then
			Conference = external_link( ConferenceURL, Conference, ConferenceURL_origin, nil );
		end
		Conference = sepc .. " " .. Conference .. ConferenceFormat;
	elseif utilities.is_set (ConferenceURL) then
		Conference = sepc .. " " .. external_link( ConferenceURL, nil, ConferenceURL_origin, nil );
	end

	local Position = '';
	if not utilities.is_set (Position) then
		local Minutes = A['Minutes'];
		local Time = A['Time'];

		if utilities.is_set (Minutes) then
			if utilities.is_set (Time) then
				table.insert( z.message_tail, { utilities.set_message ( 'err_redundant_parameters', {utilities.wrap_style ('parameter', 'minutes') .. ' và ' .. utilities.wrap_style ('parameter', 'time')}, true ) } );
			end
			Position = " " .. Minutes .. " " .. cfg.messages['minutes'];
		else
			if utilities.is_set (Time) then
				local TimeCaption = A['TimeCaption']
				if not utilities.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

	Page, Pages, Sheet, Sheets = format_pages_sheets (Page, Pages, Sheet, Sheets, config.CitationClass, Periodical_origin, sepc, NoPP, use_lowercase);

	At = utilities.is_set (At) and (sepc .. " " .. At) or "";
	Position = utilities.is_set (Position) and (sepc .. " " .. Position) or "";
	if config.CitationClass == 'map' then
		local Sections = A['Sections'];											-- Section (singular) is an alias of Chapter so set earlier
		local Inset = A['Inset'];
		
		if utilities.is_set ( Inset ) then
			Inset = sepc .. " " .. wrap_msg ('inset', Inset, use_lowercase);
		end			

		if utilities.is_set ( Sections ) then
			Section = sepc .. " " .. wrap_msg ('sections', Sections, use_lowercase);
		elseif utilities.is_set ( Section ) then
			Section = sepc .. " " .. wrap_msg ('section', Section, use_lowercase);
		end
		At = At .. Inset .. Section;		
	end	

	local Others = A['Others'];
	if utilities.is_set (Others) and 0 == #a and 0 == #e then					-- add maint cat when |others= has value and used without |author=, |editor=
		if config.CitationClass == "AV-media-notes"
		or config.CitationClass == "audio-visual" then							-- special maint for AV/M which has a lot of 'false' positives right now
			utilities.set_message ('maint_others_avm')
		else
			utilities.set_message ('maint_others');
		end
	end
	Others = utilities.is_set (Others) and (sepc .. " " .. Others) or "";
	
	if utilities.is_set (Translators) then
		Others = safe_join ({sepc .. ' ', wrap_msg ('translated', Translators, use_lowercase), Others}, sepc);
	end
	if utilities.is_set (Interviewers) then
		Others = safe_join ({sepc .. ' ', wrap_msg ('interview', Interviewers, use_lowercase), Others}, sepc);
	end
	
	local TitleNote = A['TitleNote'];
	TitleNote = utilities.is_set (TitleNote) and (sepc .. " " .. TitleNote) or "";
	if utilities.is_set (Edition) then
		if Edition:match ('%f[%a][Ee]d%n?%.?$') or Edition:match ('%f[%a][Ee]dition$') then -- Ed, ed, Ed., ed., Edn, edn, Edn., edn.
			table.insert( z.message_tail, { utilities.set_message ( 'err_extra_text_edition')}); -- add error
		end
		Edition = " " .. wrap_msg ('edition', vi_formatedition(Edition));
	else
		Edition = '';
	end

	Series = utilities.is_set (Series) and wrap_msg ('series', {sepc, Series}) or "";	-- not the same as SeriesNum
	local Agency = A['Agency'];
	Agency = utilities.is_set (Agency) and wrap_msg ('agency', {sepc, Agency}) or "";
	Volume = format_volume_issue (Volume, Issue, config.CitationClass, Periodical_origin, sepc, use_lowercase);

	if utilities.is_set (AccessDate) then
		local retrv_text = " " .. cfg.messages['retrieved']

		AccessDate = vi_formatdate(AccessDate, true);
		AccessDate = nowrap_date (AccessDate);									-- wrap in nowrap span if date in appropriate format
		if (sepc ~= ".") then retrv_text = mw.ustring.lower(retrv_text) end				-- if mode is cs2, lower case
		AccessDate = utilities.substitute (retrv_text, AccessDate);				-- add retrieved text

		AccessDate = utilities.substitute (cfg.presentation['accessdate'], {sepc, AccessDate});	-- allow editors to hide accessdates
	end
	
	if utilities.is_set (ID) then ID = sepc .. " " .. ID; end
	
	local Docket = A['Docket'];
   	if "thesis" == config.CitationClass and utilities.is_set (Docket) then
		ID = sepc .. " Docket " .. Docket .. ID;
	end
   	if "report" == config.CitationClass and utilities.is_set (Docket) then		-- for cite report when |docket= is set
		ID = sepc .. ' ' .. Docket;												-- overwrite ID even if |id= is set
	end

	if utilities.is_set (URL) then
		URL = " " .. external_link( URL, nil, URL_origin, UrlAccess );
	end

	local Quote = A['Quote'];
	local TransQuote = A['TransQuote'];
	local ScriptQuote = A['ScriptQuote'];
	if utilities.is_set (Quote) or utilities.is_set (TransQuote) or utilities.is_set (ScriptQuote) then

		if utilities.is_set (Quote) then
			if Quote:sub(1, 1) == '"' and Quote:sub(-1, -1) == '"' then			-- if first and last characters of quote are quote marks
				Quote = Quote:sub(2, -2);										-- strip them off
			end
		end

		Quote = utilities.wrap_style ('quoted-text', Quote );					-- wrap in <q>...</q> tags
	
		if utilities.is_set (ScriptQuote) then
			Quote = script_concatenate (Quote, ScriptQuote, 'script-quote');	-- <bdi> tags, lang attribute, categorization, etc.; must be done after quote is wrapped
		end

		if utilities.is_set (TransQuote) then
			if TransQuote:sub(1, 1) == '"' and TransQuote:sub(-1, -1) == '"' then -- if first and last characters of |trans-quote are quote marks
				TransQuote = TransQuote:sub(2, -2); -- strip them off
			end
			Quote = Quote .. " " .. utilities.wrap_style ('trans-quoted-title', TransQuote );
		end

		if utilities.is_set (QuotePage) or utilities.is_set (QuotePages) then	-- add page prefix
			local quote_prefix = '';
			if utilities.is_set (QuotePage) then
				extra_text_in_page_check (QuotePage, 'quote-page');				-- add to maint cat if |quote-page= value begins with what looks like p., pp., etc.
				if not NoPP then
					quote_prefix = utilities.substitute (cfg.messages['p-prefix'], {sepc, QuotePage}), '', '', '';
				else
					quote_prefix = utilities.substitute (cfg.messages['nopp'], {sepc, QuotePage}), '', '', '';
				end
			elseif utilities.is_set (QuotePages) then
				extra_text_in_page_check (QuotePages, 'quote-pages');			-- add to maint cat if |quote-pages= value begins with what looks like p., pp., etc.
				if tonumber(QuotePages) ~= nil and not NoPP then				-- if only digits, assume single page
					quote_prefix = utilities.substitute (cfg.messages['p-prefix'], {sepc, QuotePages}), '', '';
				elseif not NoPP then
					quote_prefix = utilities.substitute (cfg.messages['pp-prefix'], {sepc, QuotePages}), '', '';
				else
					quote_prefix = utilities.substitute (cfg.messages['nopp'], {sepc, QuotePages}), '', '';
				end
			end
                        
			Quote = quote_prefix .. ": " .. Quote;
		else
			Quote = sepc .. " " .. Quote;
		end

		PostScript = "";														-- cs1|2 does not supply terminal punctuation when |quote= is set
	end
	
	-- We check length of PostScript here because it will have been nuked by
	-- the quote parameters. We'd otherwise emit a message even if there wasn't
	-- a displayed postscript.
	-- TODO: Should the max size (1) be configurable?
	-- TODO: Should we check a specific pattern?
	if utilities.is_set(PostScript) and mw.ustring.len(PostScript) > 1 then
		utilities.set_message('maint_postscript')
	end
	
	local Archived
	if utilities.is_set (ArchiveURL) then
		local arch_text;
		if not utilities.is_set (ArchiveDate) then
			ArchiveDate = utilities.set_message ('err_archive_missing_date');
		else
			ArchiveDate = vi_formatdate(ArchiveDate, true)
		end
		if "live" == UrlStatus then
			arch_text = cfg.messages['archived'];
			if sepc ~= "." then arch_text = mw.ustring.lower(arch_text) end
			Archived = sepc .. " " .. utilities.substitute ( cfg.messages['archived-live'],
				{ external_link( ArchiveURL, arch_text, A:ORIGIN('ArchiveURL'), nil ) .. ArchiveFormat, ArchiveDate } );
			if not utilities.is_set (OriginalURL) then
				Archived = Archived .. " " .. utilities.set_message ('err_archive_missing_url');							   
			end
		elseif utilities.is_set (OriginalURL) then								-- UrlStatus is empty, 'dead', 'unfit', 'usurped', 'bot: unknown'
			if utilities.in_array (UrlStatus, {'unfit', 'usurped', 'bot: unknown'}) then
				arch_text = cfg.messages['archived-unfit'];
				if sepc ~= "." then arch_text = mw.ustring.lower(arch_text) end
				Archived = sepc .. " " .. arch_text .. ArchiveDate;				-- format already styled
				if 'bot: unknown' == UrlStatus then
					utilities.set_message ('maint_bot_unknown');				-- and add a category if not already added
				else
					utilities.set_message ('maint_unfit');						-- and add a category if not already added
				end
			else																-- UrlStatus is empty, 'dead'
				arch_text = cfg.messages['archived-dead'];
				if sepc ~= "." then arch_text = mw.ustring.lower(arch_text) end
				Archived = sepc .. " " .. utilities.substitute ( arch_text,
					{ external_link( OriginalURL, cfg.messages['original'], OriginalURL_origin, OriginalAccess ) .. OriginalFormat, ArchiveDate } );	-- format already styled
			end	
		else																	-- OriginalUrl not set
			arch_text = cfg.messages['archived-missing'];
			if sepc ~= "." then arch_text = arch_text:lower() end
			Archived = sepc .. " " .. utilities.substitute ( arch_text, 
				{ utilities.set_message ('err_archive_missing_url'), ArchiveDate } );
		end
	elseif utilities.is_set (ArchiveFormat) then
		Archived = ArchiveFormat;												-- if set and ArchiveURL not set ArchiveFormat has error message
	else
		Archived = ""
	end
	
	local Lay = '';
	local LaySource = A['LaySource'];
	local LayURL = A['LayURL'];
	local LayFormat = A['LayFormat'];
	LayFormat = style_format (LayFormat, LayURL, 'lay-format', 'lay-url');
	if utilities.is_set (LayURL) then
		if utilities.is_set (LayDate) then LayDate = " (" .. vi_formatdate(LayDate) .. ")" end
		if utilities.is_set (LaySource) then 
			LaySource = " &ndash; ''" .. utilities.safe_for_italics (LaySource) .. "''";
		else
			LaySource = "";
		end
		if sepc == '.' then
			Lay = sepc .. " " .. external_link( LayURL, cfg.messages['lay summary'], A:ORIGIN('LayURL'), nil ) .. LayFormat .. LaySource .. LayDate
		else
			Lay = sepc .. " " .. external_link( LayURL, mw.ustring.lower(cfg.messages['lay summary']), A:ORIGIN('LayURL'), nil ) .. LayFormat .. LaySource .. LayDate
		end			
	elseif utilities.is_set (LayFormat) then									-- Test if |lay-format= is given without giving a |lay-url=
		Lay = sepc .. LayFormat;												-- if set and LayURL not set, then LayFormat has error message
	end

	local TranscriptURL = A['TranscriptURL']
	local TranscriptFormat = A['TranscriptFormat'];
	TranscriptFormat = style_format (TranscriptFormat, TranscriptURL, 'transcript-format', 'transcripturl');
	local Transcript = A['Transcript'];
	local TranscriptURL_origin = A:ORIGIN('TranscriptURL');						-- get name of parameter that holds TranscriptURL
	if utilities.is_set (Transcript) then
		if utilities.is_set (TranscriptURL) then
			Transcript = external_link( TranscriptURL, Transcript, TranscriptURL_origin, nil );
		end
		Transcript = sepc .. ' ' .. Transcript .. TranscriptFormat;
	elseif utilities.is_set (TranscriptURL) then
		Transcript = external_link( TranscriptURL, nil, TranscriptURL_origin, nil );
	end

	local Publisher;
	if utilities.is_set (PublicationDate) then
		PublicationDate = wrap_msg ('published', PublicationDate);
	end
	if utilities.is_set (PublisherName) then
		if utilities.is_set (PublicationPlace) then
			Publisher = sepc .. " " .. PublicationPlace .. ": " .. PublisherName .. PublicationDate;
		else
			Publisher = sepc .. " " .. PublisherName .. PublicationDate;  
		end			
	elseif utilities.is_set (PublicationPlace) then 
		Publisher= sepc .. " " .. PublicationPlace .. PublicationDate;
	else 
		Publisher = PublicationDate;
	end
	
	local TransPeriodical =  A['TransPeriodical'];
	local TransPeriodical_origin =  A:ORIGIN ('TransPeriodical');
	-- Several of the above rely upon detecting this as nil, so do it last.
	if (utilities.is_set (Periodical) or utilities.is_set (ScriptPeriodical) or utilities.is_set (TransPeriodical)) then
		if utilities.is_set (Title) or utilities.is_set (TitleNote) then 
			Periodical = sepc .. " " .. format_periodical (ScriptPeriodical, ScriptPeriodical_origin, Periodical, TransPeriodical, TransPeriodical_origin);
		else 
			Periodical = format_periodical (ScriptPeriodical, ScriptPeriodical_origin, Periodical, TransPeriodical, TransPeriodical_origin);
		end
	end
	
	local Language = A['Language'];
	if utilities.is_set (Language) then
		Language = language_parameter (Language);								-- format, categories, name from ISO639-1, etc.
	else
		Language='';															-- language not specified so make sure this is an empty string;
	--[[ TODO: need to extract the wrap_msg from language_parameter
	so that we can solve parentheses bunching problem with Format/Language/TitleType
	]]
	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 utilities.is_set (Periodical) then									-- if Periodical, perhaps because of an included |website= or |journal= parameter 
			if utilities.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;
	local tcommon2;																-- used for book cite when |contributor= is set
	
	if utilities.in_array (config.CitationClass, {"journal", "citation"}) and utilities.is_set (Periodical) then
		if utilities.is_set (Others) then Others = safe_join ({Others, sepc .. " "}, sepc) end		-- add terminal punctuation & space; check for dup sepc; TODO why do we need to do this here?
		tcommon = safe_join( {Others, Title, TitleNote, Conference, Periodical, Format, TitleType, Series, Language, Edition, Publisher, Agency, Volume}, sepc );
	elseif utilities.in_array (config.CitationClass, {"book", "citation"}) and not utilities.is_set (Periodical) then		-- special cases for book cites
		if utilities.is_set (Contributors) then									-- when we are citing foreword, preface, introduction, etc.
			tcommon = safe_join( {Title, TitleNote}, sepc );					-- author and other stuff will come after this and before tcommon2
			tcommon2 = safe_join( {Conference, Periodical, Format, TitleType, Series, Language, Volume, Others, Edition, Publisher, Agency}, sepc );
		else
			tcommon = safe_join( {Title, TitleNote, Conference, Periodical, Format, TitleType, Series, Language, Volume, Others, Edition, Publisher, Agency}, sepc );
		end

	elseif 'map' == config.CitationClass then									-- special cases for cite map
		if utilities.is_set (Chapter) then										-- map in a book; TitleType is part of Chapter
			tcommon = safe_join( {Title, Format, Edition, Scale, Series, Language, Cartography, Others, Publisher, Volume}, sepc );
		elseif utilities.is_set (Periodical) then								-- map in a periodical
			tcommon = safe_join( {Title, TitleType, Format, Periodical, Scale, Series, Language, Cartography, Others, Publisher, Volume}, sepc );
		else																	-- a sheet or stand-alone map
			tcommon = safe_join( {Title, TitleType, Format, Edition, Scale, Series, Language, Cartography, Others, Publisher}, sepc );
		end
		
	elseif 'episode' == config.CitationClass then								-- special case for cite episode
		tcommon = safe_join( {Title, TitleNote, TitleType, Series, Language, Edition, Publisher}, sepc );

	else																		-- all other CS1 templates
		tcommon = safe_join( {Title, TitleNote, Conference, Periodical, Format, TitleType, Series, Language, 
			Volume, Others, Edition, Publisher, Agency}, sepc );
	end
	
	if #ID_list > 0 then
		ID_list = safe_join( { sepc .. " ",  table.concat( ID_list, sepc .. " " ), ID }, sepc );
	else
		ID_list = ID;
	end
	
	local Via = A['Via'];
	Via = utilities.is_set (Via) and  wrap_msg ('via', Via) or '';
	local idcommon;
	if 'audio-visual' == config.CitationClass or 'episode' == config.CitationClass then	-- special case for cite AV media & cite episode position transcript
		idcommon = safe_join( { ID_list, URL, Archived, Transcript, AccessDate, Via, Lay, Quote }, sepc );
	else
		idcommon = safe_join( { ID_list, URL, Archived, AccessDate, Via, Lay, Quote }, sepc );
	end
	
	local text;
	local pgtext = Position .. Sheet .. Sheets .. Page .. Pages .. At;

	local OrigDate = A['OrigDate'];
	OrigDate = utilities.is_set (OrigDate) and wrap_msg ('origdate', OrigDate) or '';
	if utilities.is_set (Date) then
		if utilities.is_set (Authors) or utilities.is_set (Editors) then		-- date follows authors or editors when authors not set
			Date = " (" .. Date .. ")" .. OrigDate .. sepc .. " ";				-- in parentheses
		else																	-- neither of authors and editors set
			if (string.sub(tcommon, -1, -1) == sepc) then						-- if the last character of tcommon is sepc
				Date = " " .. Date .. OrigDate;									-- Date does not begin with sepc
			else
				Date = sepc .. " " .. Date .. OrigDate;							-- Date begins with sepc
			end
		end
	end	
	if utilities.is_set (Authors) then
		if (not utilities.is_set (Date)) then									-- when date is set it's in parentheses; no Authors termination
			Authors = terminate_name_list (Authors, sepc);						-- when no date, terminate with 0 or 1 sepc and a space
		end
		if utilities.is_set (Editors) then
			local in_text = " ";
			local post_text = "";
			if utilities.is_set (Chapter) and 0 == #c then
				in_text = in_text .. cfg.messages['in'] .. " "
				if (sepc ~= '.') then
					in_text = in_text:lower()									-- lowercase for cs2
				end
			end
			if EditorCount <= 1 then
				post_text = " (" .. cfg.messages['editor'] .. ")";				-- be consistent with no-author, no-date case
			else
				post_text = " (" .. cfg.messages['editors'] .. ")";
			end
			Editors = terminate_name_list (in_text .. Editors .. post_text, sepc);	-- terminate with 0 or 1 sepc and a space
		end
		if utilities.is_set (Contributors) then									-- book cite and we're citing the intro, preface, etc.
			local by_text = sepc .. ' ' .. cfg.messages['by'] .. ' ';
			if (sepc ~= '.') then by_text = by_text:lower() end					-- lowercase for cs2
			Authors = by_text .. Authors;										-- author follows title so tweak it here
			if utilities.is_set (Editors) and utilities.is_set (Date) then		-- when Editors make sure that Authors gets terminated
				Authors = terminate_name_list (Authors, sepc);					-- terminate with 0 or 1 sepc and a space
			end
			if (not utilities.is_set (Date)) then								-- when date is set it's in parentheses; no Contributors termination
				Contributors = terminate_name_list (Contributors, sepc);		-- terminate with 0 or 1 sepc and a space
			end
			text = safe_join( {Contributors, Date, Chapter, tcommon, Authors, Place, Editors, tcommon2, pgtext, idcommon }, sepc );
		else
			text = safe_join( {Authors, Date, Chapter, Place, Editors, tcommon, pgtext, idcommon }, sepc );
		end
	elseif utilities.is_set (Editors) then
		if utilities.is_set (Date) then
			if EditorCount <= 1 then
				Editors = Editors .. " " .. cfg.messages['editor'];
			else
				Editors = Editors .. " " .. cfg.messages['editors'];
			end
		else
			if EditorCount <= 1 then
				Editors = Editors .. " (" .. cfg.messages['editor'] .. ")" .. sepc .. " "
			else
				Editors = Editors .. " (" .. cfg.messages['editors'] .. ")" .. sepc .. " "
			end
		end
		text = safe_join( {Editors, Date, Chapter, Place, tcommon, pgtext, idcommon}, sepc );
	else
		if utilities.in_array (config.CitationClass, {"journal", "citation"}) and utilities.is_set (Periodical) then
			text = safe_join( {Chapter, Place, tcommon, pgtext, Date, idcommon}, sepc );
		else
			text = safe_join( {Chapter, Place, tcommon, Date, pgtext, idcommon}, sepc );
		end
	end
	
	if utilities.is_set (PostScript) and PostScript ~= sepc then
		text = safe_join( {text, sepc}, sepc ); 								-- Deals with italics, spaces, etc.
		text = text:sub(1, -sepc:len() - 1);
	end	
	
	text = safe_join( {text, PostScript}, sepc );

	-- Now enclose the whole thing in a <cite> element
	local options = {};
	
	if utilities.is_set (config.CitationClass) and config.CitationClass ~= "citation" then
		options.class = string.format ('%s %s %s', 'citation', config.CitationClass, utilities.is_set (Mode) and Mode or 'cs1');	-- class=citation required for blue highlight when used with |ref=
	else
		options.class = string.format ('%s %s', 'citation', utilities.is_set (Mode) and Mode or 'cs2');
	end

	local Ref = A['Ref'];
	if 'harv' == Ref then														-- need to check this before setting to default
		utilities.set_message ('maint_ref_harv');								-- add maint cat to identify templates that have this now-extraneous param value
	elseif not utilities.is_set (Ref) then
		Ref = 'harv';															-- set as default when not set externally
	end
	if 'none' ~= cfg.keywords_xlate[Ref:lower()] then
		local id = Ref
		local namelist = {};													-- holds selected contributor, author, editor name list
		local year = first_set ({Year, anchor_year}, 2);						-- Year first for legacy citations and for YMD dates that require disambiguation

		if #c > 0 then															-- if there is a contributor list
			namelist = c;														-- select it
		elseif #a > 0 then														-- or an author list
			namelist = a;
		elseif #e > 0 then														-- or an editor list
			namelist = e;
		end
		local citeref_id
		if #namelist > 0 then													-- if there are names in namelist
			citeref_id = make_citeref_id (namelist, year);						-- go make the CITEREF anchor
		else
			citeref_id = '';													-- unset
		end
		if citeref_id == Ref then
			utilities.set_message ('maint_ref_duplicates_default');
		end
		if 'harv' == Ref then
			id = citeref_id
		end
		options.id = id;
	end
	
	if string.len(text:gsub("<span[^>/]*>(.-)</span>", "%1"):gsub("%b<>", "")) <= 2 then	-- remove <span> tags and other HTML-like markup; then get length of what remains
		z.error_categories = {};
		text = utilities.set_message ('err_empty_citation');
		z.message_tail = {};
	end
	
	local render = {};															-- here we collect the final bits for concatenation into the rendered citation

	if utilities.is_set (options.id) then										-- here we wrap the rendered citation in <cite ...>...</cite> tags
		table.insert (render, utilities.substitute (cfg.presentation['cite-id'], {mw.uri.anchorEncode(options.id), mw.text.nowiki(options.class), text}));	-- when |ref= is set
	else
		table.insert (render, utilities.substitute (cfg.presentation['cite'], {mw.text.nowiki(options.class), text}));	-- all other cases
	end		

	table.insert (render, utilities.substitute (cfg.presentation['ocins'], {OCinSoutput}));	-- append metadata to the citation

	if 0 ~= #z.message_tail then
		table.insert (render, ' ');
		for i,v in ipairs( z.message_tail ) do
			if utilities.is_set (v[1]) then
				if i == #z.message_tail then
					table.insert (render, utilities.error_comment ( v[1], v[2] ));
				else
					table.insert (render, utilities.error_comment ( v[1] .. "; ", v[2] ));
				end
			end
		end
	end

	if 0 ~= #z.maintenance_cats then
		local maint_msgs = {};													-- here we collect all of the maint messages
		for _, v in ipairs( z.maintenance_cats ) do								-- append maintenance categories
			local maint = {};													-- here we assemble a maintenence message
			table.insert (maint, v);											-- maint msg is the category name
			table.insert (maint, ' (');											-- open the link text
			table.insert (maint, utilities.substitute (cfg.messages[':cat wikilink'], {v}));	-- add the link
			table.insert (maint, ')');											-- and close it
			table.insert (maint_msgs, table.concat (maint));					-- assemble new maint message and add it to the maint_msgs table
		end
		table.insert (render, utilities.substitute (cfg.presentation['hidden-maint'], table.concat (maint_msgs, ' ')));	-- wrap the group of maint message with proper presentation and save
	end
	
	if not no_tracking_cats then
		for _, v in ipairs( z.error_categories ) do								-- append error categories
			table.insert (render, utilities.substitute (cfg.messages['cat wikilink'], {v}));
		end
		for _, v in ipairs( z.maintenance_cats ) do								-- append maintenance categories
			table.insert (render, utilities.substitute (cfg.messages['cat wikilink'], {v}));
		end
		for _, v in ipairs( z.properties_cats ) do								-- append properties categories
			table.insert (render, utilities.substitute (cfg.messages['cat wikilink'], {v}));
		end
	end

	return table.concat (render);	
end


--[[--------------------------< V A L I D A T E >--------------------------------------------------------------

Looks for a parameter's name in one of several whitelists.

Parameters in the whitelist can have three values:
	true - active, supported parameters
	false - deprecated, supported parameters
	nil - unsupported parameters
	
]]

local function validate (name, cite_class, empty)
	local name = tostring (name);
	local enum_name;															-- for enumerated parameters, is name with enumerator replaced with '#'
	local state;
	local function state_test (state, name)										-- local function to do testing of state values
		if true == state then return true; end									-- valid actively supported parameter
		if false == state then
			if empty then return nil; end										-- empty deprecated parameters are treated as unknowns
			deprecated_parameter (name);										-- parameter is deprecated but still supported
			return true;
		end
		if 'discouraged' == state then
			discouraged_parameter (name);										-- parameter is discouraged but still supported
			return true;
		end
		return nil;
	end		

	if name:find ('#') then														-- # is a cs1|2 reserved character so parameters with # not permitted
		return nil;
	end

	if utilities.in_array (cite_class, whitelist.preprint_template_list ) then	-- limited parameter sets allowed for these templates
		state = whitelist.limited_basic_arguments[name];
		if true == state_test (state, name) then return true; end

		state = whitelist.preprint_arguments[cite_class][name];					-- look in the parameter-list for the template identified by cite_class
		if true == state_test (state, name) then return true; end

																				-- limited enumerated parameters list
		enum_name = name:gsub("%d+", "#" );										-- replace digit(s) with # (last25 becomes last#) (mw.ustring because non-Western 'local' digits)
		state = whitelist.limited_numbered_arguments[enum_name];
		if true == state_test (state, name) then return true; end

		return false;															-- not supported because not found or name is set to nil
	end																			-- end limited parameter-set templates

	if utilities.in_array (cite_class, whitelist.unique_param_template_list) then 	-- experiment for template-specific parameters for templates that accept parameters from the basic argument list
		state = whitelist.unique_arguments[cite_class][name];					-- look in the template-specific parameter-lists for the template identified by cite_class
		if true == state_test (state, name) then return true; end
	end																			-- if here, fall into general validation
		
	state = whitelist.basic_arguments[name];									-- all other templates; all normal parameters allowed
	if true == state_test (state, name) then return true; end

																				-- all enumerated parameters allowed
	enum_name = name:gsub("%d+", "#" );											-- replace digit(s) with # (last25 becomes last#) (mw.ustring because non-Western 'local' digits)
	state = whitelist.numbered_arguments[enum_name];
	if true == state_test (state, name) then return true; end

	return false;																-- not supported because not found or name is set to nil
end


--[=[-------------------------< I N T E R _ W I K I _ C H E C K >----------------------------------------------

check <value> for inter-language interwiki-link markup.  <prefix> must be a MediaWiki-recognized language
code.  when these values have the form (without leading colon):
	[[<prefix>:link|label]] return label as plain-text
	[[<prefix>:link]] return <prefix>:link as plain-text

return value as is else

]=]

local function inter_wiki_check (parameter, value)
	local prefix = value:match ('%[%[(%a+):');									-- get an interwiki prefix if one exists
	local _;
	
	if prefix and cfg.inter_wiki_map[prefix:lower()] then						-- if prefix is in the map, needs preceding colon so
		table.insert( z.message_tail, {utilities.set_message ('err_bad_paramlink', parameter)});	-- emit an error message
		_, value, _ = utilities.is_wikilink (value);							-- extract label portion from wikilink
	end
	return value;
end


--[[--------------------------< M I S S I N G _ P I P E _ C H E C K >------------------------------------------

Look at the contents of a parameter. If the content has a string of characters and digits followed by an equal
sign, compare the alphanumeric string to the list of cs1|2 parameters.  If found, then the string is possibly a
parameter that is missing its pipe.  There are two tests made:
	{{cite ... |title=Title access-date=2016-03-17}}	-- the first parameter has a value and whitespace separates that value from the missing pipe parameter name
	{{cite ... |title=access-date=2016-03-17}}			-- the first parameter has no value (whitespace after the first = is trimmed by MediaWiki)
cs1|2 shares some parameter names with XML/HTML attributes: class=, title=, etc.  To prevent false positives XML/HTML
tags are removed before the search.

If a missing pipe is detected, this function adds the missing pipe maintenance category.

]]

local function missing_pipe_check (parameter, value)
	local capture;
	value = value:gsub ('%b<>', '');											-- remove XML/HTML tags because attributes: class=, title=, etc.

	capture = value:match ('%s+(%a[%w%-]+)%s*=') or value:match ('^(%a[%w%-]+)%s*=');	-- find and categorize parameters with possible missing pipes
	if capture and validate (capture) then										-- if the capture is a valid parameter name
		table.insert( z.message_tail, {utilities.set_message ('err_missing_pipe', parameter)});
	end
end


--[[--------------------------< H A S _ E X T R A N E O U S _ P U N C T >--------------------------------------

look for extraneous terminal punctuation in most parameter values; parameters listed in skip table are not checked

]]

local function has_extraneous_punc (param, value)
	if 'number' == type (param) then
		return;
	end
	
	param = param:gsub ('%d+', '#');											-- enumerated name-list mask params allow terminal punct; normalize 
	if cfg.punct_skip[param] then
		return;																	-- parameter name found in the skip table so done
	end
	
	if value:match ('[,;:]$') then
		utilities.set_message ('maint_extra_punct');							-- has extraneous punctuation; add maint cat
	end
end


--[[--------------------------< C I T A T I O N >--------------------------------------------------------------

This is used by templates such as {{cite book}} to create the actual citation text.

]]

local function citation(frame)
	Frame = frame;																-- save a copy in case we need to display an error message in preview mode
	local pframe = frame:getParent()
	local styles;
	
	if nil ~= string.find (frame:getTitle(), 'sandbox', 1, true) then			-- did the {{#invoke:}} use sandbox version?
		cfg = mw.loadData ('Mô đun:Citation/CS1/Configuration/sandbox');		-- load sandbox versions of support modules
		whitelist = mw.loadData ('Mô đun:Citation/CS1/Whitelist/sandbox');
		utilities = require ('Mô đun:Citation/CS1/Utilities/sandbox');
		validation = require ('Mô đun:Citation/CS1/Date_validation/sandbox');
		identifiers = require ('Mô đun:Citation/CS1/Identifiers/sandbox');
		metadata = require ('Mô đun:Citation/CS1/COinS/sandbox');
		styles = 'Mô đun:Citation/CS1/sandbox/styles.css';
		
	else																		-- otherwise
		cfg = mw.loadData ('Mô đun:Citation/CS1/Configuration');				-- load live versions of support modules
		whitelist = mw.loadData ('Mô đun:Citation/CS1/Whitelist');
		utilities = require ('Mô đun:Citation/CS1/Utilities');
		validation = require ('Mô đun:Citation/CS1/Date_validation');
		identifiers = require ('Mô đun:Citation/CS1/Identifiers');
		metadata = require ('Mô đun:Citation/CS1/COinS');
		styles = 'Mô đun:Citation/CS1/styles.css';
	end

	utilities.set_selected_modules (cfg);										-- so that functions in Utilities can see the selected cfg tables
	identifiers.set_selected_modules (cfg, utilities);							-- so that functions in Identifiers can see the selected cfg tables and selected Utilities module
	validation.set_selected_modules (cfg, utilities);							-- so that functions in Date validataion can see selected cfg tables and the selected Utilities module
	metadata.set_selected_modules (cfg, utilities);								-- so that functions in COinS can see the selected cfg tables and selected Utilities module

	z = utilities.z;															-- table of error and category tables in Module:Citation/CS1/Utilities

	local args = {};															-- table where we store all of the template's arguments
	local suggestions = {};														-- table where we store suggestions if we need to loadData them
	local error_text, error_state;

	local config = {};															-- table to store parameters from the module {{#invoke:}}
	for k, v in pairs( frame.args ) do											-- get parameters from the {{#invoke}} frame
		config[k] = v;
	--	args[k] = v;															-- crude debug support that allows us to render a citation from module {{#invoke:}}; skips parameter validation; TODO: keep?
	end	

	local capture;																-- the single supported capture when matching unknown parameters using patterns
	local empty_unknowns = {};													-- sequence table to hold empty unknown params for error message listing
	for k, v in pairs( pframe.args ) do											-- get parameters from the parent (template) frame
		v = mw.ustring.gsub (v, '^%s*(.-)%s*$', '%1');							-- trim leading/trailing whitespace; when v is only whitespace, becomes empty string
		if v ~= '' then
			if ('string' == type (k)) then
				k = mw.ustring.gsub (k, '%d', cfg.date_names.local_digits);		-- for enumerated parameters, translate 'local' digits to Western 0-9
			end
			if not validate( k, config.CitationClass ) then			
				error_text = "";
				if type( k ) ~= 'string' then
					-- exclude empty numbered parameters
					if v:match("%S+") ~= nil then
						error_text, error_state = utilities.set_message ( 'err_text_ignored', {v}, true );
					end
				elseif validate( k:lower(), config.CitationClass ) then 
					error_text, error_state = utilities.set_message ( 'err_parameter_ignored_suggest', {k, k:lower()}, true );	-- suggest the lowercase version of the parameter
				else
					if nil == suggestions.suggestions then						-- if this table is nil then we need to load it
						if nil ~= string.find (frame:getTitle(), 'sandbox', 1, true) then			-- did the {{#invoke:}} use sandbox version?
							suggestions = mw.loadData( 'Mô đun:Citation/CS1/Suggestions/sandbox' );	-- use the sandbox version
						else
							suggestions = mw.loadData( 'Mô đun:Citation/CS1/Suggestions' );			-- use the live version
						end
					end
					for pattern, param in pairs (suggestions.patterns) do		-- loop through the patterns to see if we can suggest a proper parameter
						capture = k:match (pattern);							-- the whole match if no capture in pattern else the capture if a match
						if capture then											-- if the pattern matches 
							param = utilities.substitute (param, capture);		-- add the capture to the suggested parameter (typically the enumerator)
							if validate (param, config.CitationClass) then		-- validate the suggestion to make sure that the suggestion is supported by this template (necessary for limited parameter lists)
								error_text, error_state = utilities.set_message ('err_parameter_ignored_suggest', {k, param}, true);	-- set the suggestion error message
							else
								error_text, error_state = utilities.set_message ( 'err_parameter_ignored', {k}, true );	-- suggested param not supported by this template
								v = '';											-- unset
							end
						end
					end
					if not utilities.is_set (error_text) then					-- couldn't match with a pattern, is there an explicit suggestion?						
						if (suggestions.suggestions[ k:lower() ] ~= nil) and validate (suggestions.suggestions[ k:lower() ], config.CitationClass) then
							error_text, error_state = utilities.set_message ( 'err_parameter_ignored_suggest', {k, suggestions.suggestions[ k:lower() ]}, true );
						else
							error_text, error_state = utilities.set_message ( 'err_parameter_ignored', {k}, true );
							v = '';												-- unset value assigned to unrecognized parameters (this for the limited parameter lists)
						end
					end
				end				  
				if error_text ~= '' then
					table.insert( z.message_tail, {error_text, error_state} );
				end				
			end

			args[k] = v;														-- save this parameter and its value

		elseif not utilities.is_set (v) then									-- for empty parameters
			if not validate (k, config.CitationClass, true) then				-- is this empty parameter a valid parameter
				k = ('' == k) and '(empty string)' or k;						-- when k is empty string (or was space(s) trimmed to empty string), replace with descriptive text
				table.insert (empty_unknowns, utilities.wrap_style ('parameter', k));	-- format for error message and add to the list
			end
																				-- crude debug support that allows us to render a citation from module {{#invoke:}} TODO: keep?
	--	elseif args[k] ~= nil or (k == 'postscript') then						-- when args[k] has a value from {{#invoke}} frame (we don't normally do that)
	--		args[k] = v;														-- overwrite args[k] with empty string from pframe.args[k] (template frame); v is empty string here
		end																		-- not sure about the postscript bit; that gets handled in parameter validation; historical artifact?
	end	

	if 0 ~= #empty_unknowns then												-- create empty unknown error message
		table.insert (z.message_tail, {utilities.set_message ('err_param_unknown_empty', {
			1 == #empty_unknowns and '' or 'các',
			utilities.make_sep_list (#empty_unknowns, empty_unknowns)
			}, true )});
	end

	for k, v in pairs( args ) do
		if 'string' == type (k) then											-- don't evaluate positional parameters
			has_invisible_chars (k, v);											-- look for invisible characters
		end
		has_extraneous_punc (k, v);												-- look for extraneous terminal punctuation in parameter values
		missing_pipe_check (k, v);												-- do we think that there is a parameter that is missing a pipe?
		args[k] = inter_wiki_check (k, v);										-- when language interwiki-linked parameter missing leading colon replace with wiki-link label
	end

	return table.concat ({
		frame:extensionTag ('templatestyles', '', {src=styles}),
		citation0( config, args)
	});
end

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

return {citation = citation};