Module:Citation/CS1

From Vigyanwiki

<section begin=header />

Lua error in Module:TNT at line 182: Missing Commons dataset I18n/Module:TNT.tab.

<section end=header />

This module and associated sub-modules support the Citation Style 1 and Citation Style 2 citation templates. In general, it is not intended to be called directly, but is called by one of the core CS1 and CS2 templates. <section begin=module_components_table /> These files comprise the module support for CS1|2 citation templates:

CS1 | CS2 modules
live sandbox diff description
sysop Module:Citation/CS1 Module:Citation/CS1/sandbox [edit] diff Rendering and support functions
Module:Citation/CS1/Configuration Module:Citation/CS1/Configuration/sandbox [edit] diff Translation tables; error and identifier handlers
Module:Citation/CS1/Whitelist Module:Citation/CS1/Whitelist/sandbox [edit] diff List of active and deprecated CS1|2 parameters
Module:Citation/CS1/Date validation Module:Citation/CS1/Date validation/sandbox [edit] diff Date format validation functions
Module:Citation/CS1/Identifiers Module:Citation/CS1/Identifiers/sandbox [edit] diff Functions that support the named identifiers (ISBN, DOI, PMID, etc.)
Module:Citation/CS1/Utilities Module:Citation/CS1/Utilities/sandbox [edit] diff Common functions and tables
Module:Citation/CS1/COinS Module:Citation/CS1/COinS/sandbox [edit] diff Functions that render a CS1|2 template's metadata
Module:Citation/CS1/styles.css Module:Citation/CS1/sandbox/styles.css [edit] diff CSS styles applied to the CS1|2 templates
auto confirmed Module:Citation/CS1/Suggestions Module:Citation/CS1/Suggestions/sandbox [edit] diff List that maps common erroneous parameter names to valid parameter names

<section end=module_components_table />

Other documentation:

testcases


require ('strict');

--[[--------------------------< 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


--[[------------------< 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_vanc_errs;															-- Boolean flag so we only emit one Vancouver error / category
local added_generic_name_errs;													-- Boolean flag so we only emit one generic name error / category and stop testing names once an error is encountered
local Frame;																	-- holds the module's frame table
local is_preview_mode;															-- true when article is in preview mode; false when using 'Preview page with this template' (previewing the module)
local is_sandbox;																-- true when using sandbox modules to render citation


--[[--------------------------< 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
	utilities.set_message ('err_vancouver', {source, position});
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 (cfg.single_letter_2nd_lvl_domains_t) 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
		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, error_list)
	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
			table.insert (error_list, utilities.wrap_style ('parameter', k));
		end
	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 
		utilities.set_message ('err_wikilink_in_url', {});
	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 err_msg = '';
	local domain;
	local path;
	local base_url;

	if not utilities.is_set (label) then
		label = URL;
		if utilities.is_set (source) then
			utilities.set_message ('err_bare_url_missing_title', {utilities.wrap_style ('parameter', source)});
		else
			error (cfg.messages["bare_url_no_origin"]);							-- programmer error; valid parameter name does not have matching meta-parameter
		end			
	end
	if not check_url (URL) then
		utilities.set_message ('err_bad_url', {utilities.wrap_style ('parameter', source)});
	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 base_url;
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
		utilities.set_message ('err_deprecated_params', {name});				-- add error 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 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-left'], str);
			str = utilities.substitute (cfg.presentation['kern-right'], str);
		elseif mw.ustring.match (str, '%[%[[\"“”\'‘’].+%]%]')	then			-- leading quote marks
			str = utilities.substitute (cfg.presentation['kern-left'], str);
		elseif mw.ustring.match (str, '%[%[.+[\"“”\'‘’]%]%]') then				-- trailing quote marks
			str = utilities.substitute (cfg.presentation['kern-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 = 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);
		end
	
		cap = 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);
		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
			utilities.set_message ('err_script_parameter', {script_param, cfg.err_msg_supl['missing title part']});		-- 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_tag_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?
			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', {name, lang})
			else
				utilities.set_message ('err_script_parameter', {script_param, cfg.err_msg_supl['unknown language code']});	-- unknown script-language; add error message
			end
			lang = ' lang="' .. lang .. '" ';									-- convert prefix into a lang attribute
		else
			utilities.set_message ('err_script_parameter', {script_param, cfg.err_msg_supl['invalid language code']});		-- invalid language code; add error message
			lang = '';															-- invalid so set lang to empty string
		end
	else
		utilities.set_message ('err_script_parameter', {script_param, cfg.err_msg_supl['missing prefix']});				-- 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)

	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;
			utilities.set_message ('err_trans_missing_title', {'periodical'});
		end
	end

	return periodical;
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 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>
			utilities.set_message ('err_trans_missing_title', {chapter_source});
		end
	end

	return chapter;
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_t[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

				utilities.set_message ('err_invisible_char', {err_msg, utilities.wrap_style ('parameter', param), position});	-- 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


--[[--------------------------< 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 if 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


--[[--------------------------< I N T E R W I K I _ P R E F I X E N _ G E T >----------------------------------

extract interwiki prefixen from <value>.  Returns two one or two values:
	false – no prefixen
	nil – prefix exists but not recognized
	project prefix, language prefix – when value has either of:
		:<project>:<language>:<article>
		:<language>:<project>:<article>
	project prefix, nil – when <value> has only a known single-letter prefix
	nil, language prefix – when <value> has only a known language prefix

accepts single-letter project prefixen: 'd' (wikidata), 's' (wikisource), and 'w' (wikipedia) prefixes; at this
writing, the other single-letter prefixen (b (wikibook), c (commons), m (meta), n (wikinews), q (wikiquote), and
v (wikiversity)) are not supported.

]]

local function interwiki_prefixen_get (value, is_link)
	if not value:find (':%l+:') then											-- if no prefix
		return false;															-- abandon; boolean here to distinguish from nil fail returns later
	end

	local prefix_patterns_linked_t = {											-- sequence of valid interwiki and inter project prefixen
		'^%[%[:([dsw]):(%l%l+):',												-- wikilinked; project and language prefixes
		'^%[%[:(%l%l+):([dsw]):',												-- wikilinked; language and project prefixes
		'^%[%[:([dsw]):',														-- wikilinked; project prefix
		'^%[%[:(%l%l+):',														-- wikilinked; language prefix
		}
		
	local prefix_patterns_unlinked_t = {										-- sequence of valid interwiki and inter project prefixen
		'^:([dsw]):(%l%l+):',													-- project and language prefixes
		'^:(%l%l+):([dsw]):',													-- language and project prefixes
		'^:([dsw]):',															-- project prefix
		'^:(%l%l+):',															-- language prefix
		}
	
	local cap1, cap2;
	for _, pattern in ipairs ((is_link and prefix_patterns_linked_t) or prefix_patterns_unlinked_t) do
		cap1, cap2 = value:match (pattern);
		if cap1 then
			break;																-- found a match so stop looking
		end
	end
	
	if cap1 and cap2 then														-- when both then :project:language: or :language:project: (both forms allowed)
		if 1 == #cap1 then														-- length == 1 then :project:language:
			if cfg.inter_wiki_map[cap2] then									-- is language prefix in the interwiki map?
				return cap1, cap2;												-- return interwiki project and interwiki language
			end
		else																	-- here when :language:project:
			if cfg.inter_wiki_map[cap1] then									-- is language prefix in the interwiki map?
				return cap2, cap1;												-- return interwiki project and interwiki language
			end
		end
		return nil;																-- unknown interwiki language
	elseif not (cap1 or cap2) then												-- both are nil?
		return nil;																-- we got something that looks like a project prefix but isn't; return fail
	elseif 1 == #cap1 then														-- here when one capture
		return cap1, nil;														-- length is 1 so return project, nil language
	else																		-- here when one capture and its length it more than 1
		if cfg.inter_wiki_map[cap1] then										-- is language prefix in the interwiki map?
			return nil, cap1;													-- return nil project, language
		end
	end
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
					one = 0 ~= 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
					one = mask;													-- replace name with mask text (must include name-list separator)
					sep_one = " ";												-- modify name-list separator
				end
			else
				one = person.last;												-- get surname
				local first = person.first										-- get given name
				if utilities.is_set (first) then
					if ("vanc" == format) then									-- if Vancouver format
						one = one:gsub ('%.', '');								-- 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
					one = one .. namesep .. first;
				end
			end
			if utilities.is_set (person.link) then
				one = utilities.make_wikilink (person.link, one);				-- link author/editor
			end

			if one then															-- if <one> has a value (name, mdash replacement, or mask text replacement)
				local proj, tag = interwiki_prefixen_get (one, true);			-- get the interwiki prefixen if present

				if 'w' == proj and ('Wikipedia' == mw.site.namespaces.Project['name']) then
					proj = nil;													-- for stuff like :w:de:<article>, :w is unnecessary TODO: maint cat?
				end
				if proj then
					proj = ({['d'] = 'Wikidata', ['s'] = 'Wikisource', ['w'] = 'Wikipedia'})[proj];	-- :w (wikipedia) for linking from a non-wikipedia project
					if proj then 
						one = one .. utilities.wrap_style ('interproj', proj);	-- add resized leading space, brackets, static text, language name
						tag = nil;												-- unset; don't do both project and language
					end
				end
				if tag == cfg.this_wiki_code then
					tag = nil;													-- stuff like :en:<article> at en.wiki is pointless TODO: maint cat?
				end
				if tag then
					local lang = cfg.lang_tag_remap[tag] or cfg.mw_languages_by_tag_t[tag];
					if lang then												-- error messaging done in extract_names() where we know parameter names
						one = one .. utilities.wrap_style ('interwiki', lang);	-- add resized leading space, brackets, static text, language name
					end
				end

				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


--[[--------------------------< C I T E _ C L A S S _A T T R I B U T E _M A K E >------------------------------

construct <cite> tag class attribute for this citation.

<cite_class> – config.CitationClass from calling template
<mode> – value from |mode= parameter

]]

local function cite_class_attribute_make (cite_class, mode)
	local class_t = {};
	table.insert (class_t, 'citation');											-- required for blue highlight
	if 'citation' ~= cite_class then
		table.insert (class_t, cite_class);										-- identify this template for user css
		table.insert (class_t, utilities.is_set (mode) and mode or 'cs1');		-- identify the citation style for user css or javascript
	else
		table.insert (class_t, utilities.is_set (mode) and mode or 'cs2');		-- identify the citation style for user css or javascript
	end
	for _, prop_key in ipairs (z.prop_keys_t) do
		table.insert (class_t, prop_key);										-- identify various properties for user css or javascript
	end

	return table.concat (class_t, ' ');											-- make a big string and done
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=
					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 _ 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.

Same test for first except that commas should not appear in given names (MOS:JR says
that the generational suffix does not take a separator character).  Titles, degrees,
postnominals, affiliations, all normally comma separated don't belong in a citation.

<name> – name parameter value
<list_name> – AuthorList, EditorList, etc
<limit> – number of allowed commas; 1 (default) for surnames; 0 for given names

returns nothing

]]

local function name_has_mult_names (name, list_name, limit)
	local _, commas, semicolons, nbsps;
	limit = limit and limit or 1;
	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 limit < 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


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

Compares values assigned to various parameters according to the string provided as <item> in the function call.
<item> can have on of two values:
	'generic_names' – for name-holding parameters: |last=, |first=, |editor-last=, etc
	'generic_titles' – for |title=

There are two types of generic tests.  The 'accept' tests look for a pattern that should not be rejected by the
'reject' test.  For example,
	|author=[[John Smith (author)|Smith, John]]
would be rejected by the 'author' reject test.  But piped wikilinks with 'author' disambiguation should not be
rejected so the 'accept' test prevents that from happening.  Accept tests are always performed before reject
tests.

Each of the 'accept' and 'reject' sequence tables hold tables for en.wiki (['en']) and local.wiki (['local'])
that each can hold a test sequence table  The sequence table holds, at index [1], a test pattern, and, at index
[2], a boolean control value.  The control value 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.

Returns
	true when a reject test finds the pattern or string
	false when an accept test finds the pattern or string
	nil else

]=]

local function is_generic (item, value, wiki)
	local test_val;
	local str_lower = {															-- use string.lower() for en.wiki (['en']) and use mw.ustring.lower() or local.wiki (['local'])
		['en'] = string.lower,
		['local'] = mw.ustring.lower,
		}
	local str_find = {															-- use string.find() for en.wiki (['en']) and use mw.ustring.find() or local.wiki (['local'])
		['en'] = string.find,
		['local'] = mw.ustring.find,
		}

	local function test (val, test_t, wiki)										-- local function to do the testing; <wiki> selects lower() and find() functions
		val = test_t[2] and str_lower[wiki](value) or val;						-- when <test_t[2]> set to 'true', plaintext search using lowercase value
		return str_find[wiki] (val, test_t[1], 1, test_t[2]);					-- return nil when not found or matched
	end
		
	local test_types_t = {'accept', 'reject'};									-- test accept patterns first, then reject patterns
	local wikis_t = {'en', 'local'};											-- do tests for each of these keys; en.wiki first, local.wiki second

	for _, test_type in ipairs (test_types_t) do								-- for each test type
		for _, generic_value in pairs (cfg.special_case_translation[item][test_type]) do	-- spin through the list of generic value fragments to accept or reject
			for _, wiki in ipairs (wikis_t) do
				if generic_value[wiki] then
					if test (value, generic_value[wiki], wiki) then				-- go do the test
						return ('reject' == test_type);							-- param value rejected, return true; false else
					end
				end
			end
		end
	end
end


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

calls is_generic() to determine if <name> is a 'generic name' listed in cfg.generic_names; <name_alias> is the
parameter name used in error messaging

]]

local function name_is_generic (name, name_alias)
	if not added_generic_name_errs  and is_generic ('generic_names', name) then
		utilities.set_message ('err_generic_name', name_alias);					-- set an error message
		added_generic_name_errs = true;
	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, last_alias, first_alias)
	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
			name_is_numeric (last, list_name);									-- check for names that are composed of digits and punctuation
			name_is_generic (last, last_alias);									-- check for names found in the generic names list
		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_mult_names (first, list_name, 0);							-- check for multiple names in the parameter; 0 is number of allowed commas in a given name
			name_is_numeric (first, list_name);									-- check for names that are composed of digits and punctuation
			name_is_generic (first, first_alias);								-- check for names found in the generic names list
		end
		local wl_type, D = utilities.is_wikilink (first);
		if 0 ~= wl_type then
			first = D;
			utilities.set_message ('err_bad_paramlink', first_alias);
		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 );
	
		if last then															-- error check |lastn= alias for unknown interwiki link prefix; done here because this is where we have the parameter name
			local project, language = interwiki_prefixen_get (last, true);		-- true because we expect interwiki links in |lastn= to be wikilinked
			if nil == project and nil == language then							-- when both are nil
				utilities.set_message ('err_bad_paramlink', last_alias);		-- not known, emit an error message	-- TODO: err_bad_interwiki?
				last = utilities.remove_wiki_link (last);						-- remove wikilink markup; show display value only
			end
		end
		
		if link then															-- error check |linkn= alias for unknown interwiki link prefix
			local project, language = interwiki_prefixen_get (link, false);		-- false because wiki links in |author-linkn= is an error
			if nil == project and nil == language then							-- when both are nil
				utilities.set_message ('err_bad_paramlink', link_alias);		-- not known, emit an error message	-- TODO: err_bad_interwiki?
				link = nil;														-- unset so we don't link
				link_alias = nil;
			end
		end
		
		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, last_alias, first_alias);						-- 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
			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
				});																-- 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
				utilities.set_message ('err_missing_name', {list_name:match ("(%w+)List"):lower(), i - 1});	-- 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


--[[--------------------------< N A M E _ T A G _ G E T >------------------------------------------------------

attempt to decode |language=<lang_param> and return language name and matching tag; nil else.

This function looks for:
	<lang_param> as a tag in cfg.lang_tag_remap{}
	<lang_param> as a name in cfg.lang_name_remap{}
	
	<lang_param> as a name in cfg.mw_languages_by_name_t
	<lang_param> as a tag in cfg.mw_languages_by_tag_t
when those fail, presume that <lang_param> is an IETF-like tag that MediaWiki does not recognize.  Strip all
script, region, variant, whatever subtags from <lang_param> to leave just a two or three character language tag
and look for the new <lang_param> in cfg.mw_languages_by_tag_t{}

on success, returns name (in properly capitalized form) and matching tag (in lowercase); on failure returns nil

]]

local function name_tag_get (lang_param)
	local lang_param_lc = mw.ustring.lower (lang_param);						-- use lowercase as an index into the various tables
	local name;
	local tag;

	name = cfg.lang_tag_remap[lang_param_lc];									-- assume <lang_param_lc> is a tag; attempt to get remapped language name 
	if name then																-- when <name>, <lang_param> is a tag for a remapped language name
		return name, lang_param_lc;												-- so return <name> from remap and <lang_param_lc>
	end

	tag = lang_param_lc:match ('^(%a%a%a?)%-.*');								-- still assuming that <lang_param_lc> is a tag; strip script, region, variant subtags
	name = cfg.lang_tag_remap[tag];											-- attempt to get remapped language name with language subtag only
	if name then																-- when <name>, <tag> is a tag for a remapped language name
		return name, tag;														-- so return <name> from remap and <tag>
	end

	if cfg.lang_name_remap[lang_param_lc] then									-- not a tag, assume <lang_param_lc> is a name; attempt to get remapped language tag 
		return cfg.lang_name_remap[lang_param_lc][1], cfg.lang_name_remap[lang_param_lc][2];	-- for this <lang_param_lc>, return a (possibly) new name and appropriate tag
	end

	tag = cfg.mw_languages_by_name_t[lang_param_lc];							-- assume that <lang_param_lc> is a language name; attempt to get its matching tag
	
	if tag then
		return cfg.mw_languages_by_tag_t[tag], tag;								-- <lang_param_lc> is a name so return the name from the table and <tag>
	end

	name = cfg.mw_languages_by_tag_t[lang_param_lc];							-- assume that <lang_param_lc> is a tag; attempt to get its matching language name
	
	if name then
		return name, lang_param_lc;												-- <lang_param_lc> is a tag so return it and <name>
	end
	
	tag = lang_param_lc:match ('^(%a%a%a?)%-.*');								-- is <lang_param_lc> an IETF-like tag that MediaWiki doesn't recognize? <tag> gets the language subtag; nil else

	if tag then
		name = cfg.mw_languages_by_tag_t[tag];									-- attempt to get a language name u