View source for Module:Citation/CS1

local z = {
    error_categories = {};
    error_ids = {};
    message_tail = {};
}

-- Include translation message hooks, ID and error handling configuration settings.
--local cfg = mw.loadData( 'Module:Citation/CS1/Configuration/sandbox' );

-- Contains a list of all recognized parameters
--local whitelist = mw.loadData( 'Module:Citation/CS1/Whitelist/sandbox' );

--local dates = require('Module:Citation/CS1/Date_validation/sandbox').dates		-- location of date validation code

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

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

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

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

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

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

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

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

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

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

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

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

-- Formats a wiki style external link
function externallinkid(options)
    local url_string = options.id;
    if options.encode == true or options.encode == nil then
        url_string = mw.uri.encode( url_string );
    end
    return mw.ustring.format( '[[%s|%s]]%s[%s%s%s %s]',
        options.link, options.label, options.separator or "&nbsp;",
        options.prefix, url_string, options.suffix or "",
        mw.text.nowiki(options.id)
    );
end

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

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

-- Formats a link to Amazon
function amazon(id, domain)
    if not is_set(domain) then 
        domain = "com"
    elseif ( "jp" == domain or "uk" == domain ) then
        domain = "co." .. domain
    end
    local handler = cfg.id_handlers['ASIN'];
    return externallinkid({link = handler.link,
        label=handler.label , prefix="//www.amazon."..domain.."/dp/",id=id,
        encode=handler.encode, separator = handler.separator})
end

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

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

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

	local len = id:len();								-- get the length of the lccn

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

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

--[[
Format PMID and do simple error checking.  PMIDs are sequential numbers beginning at 1 and counting up.  This code checks the PMID to see that it
contains only digits and is less than test_limit; the value in local variable test_limit will need to be updated periodically as more PMIDs are issued.
]]
function pmid(id)
	local test_limit = 30000000;						-- update this value as PMIDs approach
	local handler = cfg.id_handlers['PMID'];
	local err_cat =  '';								-- presume that PMID is valid
	
	if id:match("[^%d]") then							-- if PMID has anything but digits
		err_cat = ' ' .. seterror( 'bad_pmid' );		-- set an error message
	else												-- PMID is only digits
		local id_num = tonumber(id);					-- convert id to a number for range testing
		if 1 > id_num or test_limit < id_num then		-- if PMID is outside test limit boundaries
			err_cat = ' ' .. seterror( 'bad_pmid' );	-- set an error message
		end
	end
	
	return externallinkid({link = handler.link, label = handler.label,
			prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode}) .. err_cat;
end

--[[
Determines if a PMC identifier's online version is embargoed. Compares the date in |embargo= against today's date.  If embargo date is
in the future, returns true; otherwse, returns false because the embargo has expired or |embargo= not set in this cite.
]]
function is_embargoed(embargo)
	if is_set(embargo) then
		local lang = mw.getContentLanguage();
		local good1, embargo_date, good2, todays_date;
		good1, embargo_date = pcall( lang.formatDate, lang, 'U', embargo );
		good2, todays_date = pcall( lang.formatDate, lang, 'U' );
	
		if good1 and good2 and tonumber( embargo_date ) >= tonumber( todays_date ) then	--is embargo date is in the future?
			return true;	-- still embargoed
		end
	end
	return false;			-- embargo expired or |embargo= not set
end

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

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

PMCs are sequential numbers beginning at 1 and counting up.  This code checks the PMC to see that it contains only digits and is less
than test_limit; the value in local variable test_limit will need to be updated periodically as more PMCs are issued.
]]
function pmc(id, embargo)
	local test_limit = 5000000;							-- update this value as PMCs approach
	local handler = cfg.id_handlers['PMC'];
	local err_cat =  '';								-- presume that PMC is valid
    
	local text;

	if id:match("[^%d]") then							-- if PMC has anything but digits
		err_cat = ' ' .. seterror( 'bad_pmc' );			-- set an error message
	else												-- PMC is only digits
		local id_num = tonumber(id);					-- convert id to a number for range testing
		if 1 > id_num or test_limit < id_num then		-- if PMC is outside test limit boundaries
			err_cat = ' ' .. seterror( 'bad_pmc' );		-- set an error message
		end
	end
	
	if is_embargoed(embargo) then
		text="[[" .. handler.link .. "|" .. handler.label .. "]]:" .. handler.separator .. id .. err_cat;	--still embargoed so no external link
	else
		text = externallinkid({link = handler.link, label = handler.label,			--no embargo date, ok to link to article
			prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode}) .. err_cat;
	end
	return text;
end

-- Formats a DOI and checks for DOI errors.

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

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

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

function doi(id, inactive)
    local cat = ""
    local handler = cfg.id_handlers['DOI'];
    
    local text;
	if is_set(inactive) then
		local inactive_year = inactive:match("%d%d%d%d") or '';		-- try to get the year portion from the inactive date
		text = "[[" .. handler.link .. "|" .. handler.label .. "]]:" .. id;
		if is_set(inactive_year) then
			table.insert( z.error_categories, "Pages with DOIs inactive since " .. inactive_year );
		else
			table.insert( z.error_categories, "Pages with inactive DOIs" );	-- when inactive doesn't contain a recognizable year
		end
		inactive = " (" .. cfg.messages['inactive'] .. " " .. inactive .. ")" 
	else 
		text = externallinkid({link = handler.link, label = handler.label,
			prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode})
		inactive = "" 
	end

	if nil == id:match("^10%.[^%s–]-/[^%s–]-[^%.,]$") then	-- doi must begin with '10.', must contain a fwd slash, must not contain spaces or endashes, and must not end with period or comma
		cat = ' ' .. seterror( 'bad_doi' );
	end
	return text .. inactive .. cat 
end

-- Formats an OpenLibrary link, and checks for associated errors.
function openlibrary(id)
    local code = id:sub(-1,-1)
    local handler = cfg.id_handlers['OL'];
    if ( code == "A" ) then
        return externallinkid({link=handler.link, label=handler.label,
            prefix="http://openlibrary.org/authors/OL",id=id, separator=handler.separator,
            encode = handler.encode})
    elseif ( code == "M" ) then
        return externallinkid({link=handler.link, label=handler.label,
            prefix="http://openlibrary.org/books/OL",id=id, separator=handler.separator,
            encode = handler.encode})
    elseif ( code == "W" ) then
        return externallinkid({link=handler.link, label=handler.label,
            prefix= "http://openlibrary.org/works/OL",id=id, separator=handler.separator,
            encode = handler.encode})
    else
        return externallinkid({link=handler.link, label=handler.label,
            prefix= "http://openlibrary.org/OL",id=id, separator=handler.separator,
            encode = handler.encode}) .. 
            ' ' .. seterror( 'bad_ol' );
    end
end

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

	|issn=0819 4327 gives: [http://www.worldcat.org/issn/0819 4327 0819 4327]  -- can't have spaces in an external link
	
This code now prevents that by inserting a hyphen at the issn midpoint.  It also validates the issn for length and makes sure that the checkdigit agrees
with the calculated value.  Incorrect length (8 digits), characters other than 0-9 and X, or checkdigit / calculated value mismatch will all cause a check issn
error message.  The issn is always displayed with a hyphen, even if the issn was given as a single group of 8 digits.
]]
function issn(id)
	local issn_copy = id;		-- save a copy of unadulterated issn; use this version for display if issn does not validate
	local handler = cfg.id_handlers['ISSN'];
	local text;
	local valid_issn = true;

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

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

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

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

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

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

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

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

--[[
Determines whether a URL string is valid

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

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

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

--[[
ISBN-10 and ISSN validator code calculates checksum across all isbn/issn digits including the check digit. ISBN-13 is checked in checkisbn().
If the number is valid the result will be 0. Before calling this function, issbn/issn must be checked for length and stripped of dashes,
spaces and other non-isxn characters.
]]
function is_valid_isxn (isxn_str, len)
	local temp = 0;
	isxn_str = { isxn_str:byte(1, len) };	-- make a table of bytes
	len = len+1;							-- adjust to be a loop counter
	for i, v in ipairs( isxn_str ) do		-- loop through all of the bytes and calculate the checksum
		if v == string.byte( "X" ) then		-- if checkdigit is X
			temp = temp + 10*( len - i );	-- it represents 10 decimal
		else
			temp = temp + tonumber( string.char(v) )*(len-i);
		end
	end
	return temp % 11 == 0;					-- returns true if calculation result is zero
end

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

	if len == 10 then
		if isbn_str:match( "^%d*X?$" ) == nil then return false; end
		return is_valid_isxn(isbn_str, 10);
	else
		local temp = 0;
		if isbn_str:match( "^97[89]%d*$" ) == nil then return false; end	-- isbn13 begins with 978 or 979
		isbn_str = { isbn_str:byte(1, len) };
		for i, v in ipairs( isbn_str ) do
			temp = temp + (3 - 2*(i % 2)) * tonumber( string.char(v) );
		end
		return temp % 10 == 0;
	end
end

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

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

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

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

--[[
Joins a sequence of strings together while checking for duplicate separation
characters.
]]
function safejoin( tbl, duplicate_char )
    --[[
    Note: we use string functions here, rather than ustring functions.
    
    This has considerably faster performance and should work correctly as 
    long as the duplicate_char is strict ASCII.  The strings
    in tbl may be ASCII or UTF8.
    ]]
    
    local str = '';
    local comp = '';
    local end_chr = '';
    local trim;
    for _, value in ipairs( tbl ) do
        if value == nil then value = ''; end
        
        if str == '' then
            str = value;
        elseif value ~= '' then
            if value:sub(1,1) == '<' then
                -- Special case of values enclosed in spans and other markup.
                comp = value:gsub( "%b<>", "" );
            else
                comp = value;
            end
            
            if comp:sub(1,1) == duplicate_char then
                trim = false;
                end_chr = str:sub(-1,-1);
                -- str = str .. "<HERE(enchr=" .. end_chr.. ")"
                if end_chr == duplicate_char then
                    str = str:sub(1,-2);
                elseif end_chr == "'" then
                    if str:sub(-3,-1) == duplicate_char .. "''" then
                        str = str:sub(1, -4) .. "''";
                    elseif str:sub(-5,-1) == duplicate_char .. "]]''" then
                        trim = true;
                    elseif str:sub(-4,-1) == duplicate_char .. "]''" then
                        trim = true;
                    end
                elseif end_chr == "]" then
                    if str:sub(-3,-1) == duplicate_char .. "]]" then
                        trim = true;
                    elseif str:sub(-2,-1) == duplicate_char .. "]" then
                        trim = true;
                    end
                elseif end_chr == " " then
                    if str:sub(-2,-1) == duplicate_char .. " " then
                        str = str:sub(1,-3);
                    end
                end

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

-- Attempts to convert names to initials.
function reducetoinitials(first)
    local initials = {}
    for word in string.gmatch(first, "%S+") do
        table.insert(initials, string.sub(word,1,1)) -- Vancouver format does not include full stops.
    end
    return table.concat(initials) -- Vancouver format does not include spaces.
end

-- Formats a list of people (e.g. authors / editors) 
function listpeople(control, people)
    local sep = control.sep;
    local namesep = control.namesep
    local format = control.format
    local maximum = control.maximum
    local lastauthoramp = control.lastauthoramp;
    local text = {}
    local etal = false;
    
    if sep:sub(-1,-1) ~= " " then sep = sep .. " " end
    if maximum ~= nil and maximum < 1 then return "", 0; end
    
    for i,person in ipairs(people) do
        if is_set(person.last) then
            local mask = person.mask
            local one
            local sep_one = sep;
            if maximum ~= nil and i > maximum then
                etal = true;
                break;
            elseif (mask ~= nil) then
                local n = tonumber(mask)
                if (n ~= nil) then
                    one = string.rep("&mdash;",n)
                else
                    one = mask;
                    sep_one = " ";
                end
            else
                one = person.last
                local first = person.first
                if is_set(first) then 
                    if ( "vanc" == format ) then first = reducetoinitials(first) end
                    one = one .. namesep .. first 
                end
                if is_set(person.link) then one = "[[" .. person.link .. "|" .. one .. "]]" end
                if is_set(person.link) and nil ~= person.link:find("//") then one = one .. " " .. seterror( 'bad_authorlink' ) end	-- check for url in author link;
            end
            table.insert( text, one )
            table.insert( text, sep_one )
        end
    end

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

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

-- Gets name list from the input arguments
function extractnames(args, list_name)
    local names = {};
    local i = 1;
    local last;
    
    while true do
        last = selectone( args, cfg.aliases[list_name .. '-Last'], 'redundant_parameters', i );
        if not is_set(last) then
            -- just in case someone passed in an empty parameter
            break;
        end
        names[i] = {
            last = last,
            first = selectone( args, cfg.aliases[list_name .. '-First'], 'redundant_parameters', i ),
            link = selectone( args, cfg.aliases[list_name .. '-Link'], 'redundant_parameters', i ),
            mask = selectone( args, cfg.aliases[list_name .. '-Mask'], 'redundant_parameters', i )
        };
        i = i + 1;
    end
    return names;
end

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

-- Takes a table of IDs and turns it into a table of formatted ID outputs.
function buildidlist( id_list, options )
    local new_list, handler = {};
    
    function fallback(k) return { __index = function(t,i) return cfg.id_handlers[k][i] end } end;
    
    for k, v in pairs( id_list ) do
        -- fallback to read-only cfg
        handler = setmetatable( { ['id'] = v }, fallback(k) );
        
        if handler.mode == 'external' then
            table.insert( new_list, {handler.label, externallinkid( handler ) } );
        elseif handler.mode == 'internal' then
            table.insert( new_list, {handler.label, internallinkid( handler ) } );
        elseif handler.mode ~= 'manual' then
            error( cfg.messages['unknown_ID_mode'] );
        elseif k == 'DOI' then
            table.insert( new_list, {handler.label, doi( v, options.DoiBroken ) } );
        elseif k == 'ASIN' then
            table.insert( new_list, {handler.label, amazon( v, options.ASINTLD ) } ); 
        elseif k == 'LCCN' then
            table.insert( new_list, {handler.label, lccn( v ) } );
        elseif k == 'OL' then
            table.insert( new_list, {handler.label, openlibrary( v ) } );
        elseif k == 'PMC' then
            table.insert( new_list, {handler.label, pmc( v, options.Embargo ) } );
        elseif k == 'PMID' then
            table.insert( new_list, {handler.label, pmid( v ) } );
        elseif k == 'ISSN' then
        	table.insert( new_list, {handler.label, issn( v ) } );
        elseif k == 'ISBN' then
            local ISBN = internallinkid( handler );
            if not checkisbn( v ) and not is_set(options.IgnoreISBN) then
                ISBN = ISBN .. seterror( 'bad_isbn', {}, false, " ", "" );
            end
            table.insert( new_list, {handler.label, ISBN } );                
        else
            error( cfg.messages['unknown_manual_ID'] );
        end
    end
    
    function comp( a, b )	-- used in following table.sort()
        return a[1] < b[1];
    end
    
    table.sort( new_list, comp );
    for k, v in ipairs( new_list ) do
        new_list[k] = v[2];
    end
    
    return new_list;
end
  
-- Chooses one matching parameter from a list of parameters to consider
-- Generates an error if more than one match is present.
function selectone( args, possible, error_condition, index )
    local value = nil;
    local selected = '';
    local error_list = {};
    
    if index ~= nil then index = tostring(index); end
    
    -- Handle special case of "#" replaced by empty string
    if index == '1' then
        for _, v in ipairs( possible ) do
            v = v:gsub( "#", "" );
            if is_set(args[v]) then
                if value ~= nil and selected ~= v then
                    table.insert( error_list, v );
                else
                    value = args[v];
                    selected = v;
                end
            end
        end        
    end
    
    for _, v in ipairs( possible ) do
        if index ~= nil then
            v = v:gsub( "#", index );
        end
        if is_set(args[v]) then
            if value ~= nil and selected ~=  v then
                table.insert( error_list, v );
            else
                value = args[v];
                selected = v;
            end
        end
    end
    
    if #error_list > 0 then
        local error_str = "";
        for _, k in ipairs( error_list ) do
            if error_str ~= "" then error_str = error_str .. cfg.messages['parameter-separator'] end
            error_str = error_str .. wrap( 'parameter', k );
        end
        if #error_list > 1 then
            error_str = error_str .. cfg.messages['parameter-final-separator'];
        else
            error_str = error_str .. cfg.messages['parameter-pair-separator'];
        end
        error_str = error_str .. wrap( 'parameter', selected );
        table.insert( z.message_tail, { seterror( error_condition, {error_str}, true ) } );
    end
    
    return value, selected;
end

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

--[[
This is the main function doing the majority of the citation
formatting.
]]
function citation0( config, args)
    --[[ 
    Load Input Parameters
    The argment_wrapper facillitates the mapping of multiple
    aliases to single internal variable.
    ]]
    local A = argument_wrapper( args );

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

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

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

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

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

    local ID_list = extractids( args );
    
    local Quote = A['Quote'];
    local PostScript = A['PostScript'];

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

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

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

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

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

--check this page to see if it is in one of the namespaces that cs1 is not supposed to add to the error categories.
	if not is_set(no_tracking_cats) then				-- ignore if we are already not going to categorize this page
		for k, v in pairs( cfg.uncategorized_namespaces ) do	-- otherwise, spin through the list of namespaces we don't include in error categories
			if this_page.nsText == v then				-- if we find one
				no_tracking_cats = "true";				-- set no_trackin_cats
				break;									-- and we're done
            end
        end
    end

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

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

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

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

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

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

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

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

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

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

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

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

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

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


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

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

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

    -- COinS metadata (see <http://ocoins.info/>) for
    -- automated parsing of citation information.
    local OCinSoutput = COinS{
        ['Periodical'] = Periodical,
        ['Chapter'] = Chapter,
        ['Title'] = Title,
        ['PublicationPlace'] = PublicationPlace,
        ['Date'] = first_set(COinS_date, Date),		-- COinS_date has correctly formatted date if Date is valid; any reason to keep Date here?  Should we be including invalid dates in metadata?
        ['Series'] = Series,
        ['Volume'] = Volume,
        ['Issue'] = Issue,
        ['Pages'] = get_coins_pages (first_set(Page, Pages, At)),	-- pages stripped of external links
        ['Edition'] = Edition,
        ['PublisherName'] = PublisherName,
        ['URL'] = first_set( URL, ChapterURL ),
        ['Authors'] = a,
        ['ID_list'] = ID_list,
        ['RawPage'] = this_page.prefixedText,
    };

    if is_set(Periodical) and not is_set(Chapter) and is_set(Title) then
        Chapter = Title;
        ChapterLink = TitleLink;
        TransChapter = TransTitle;
        Title = '';
        TitleLink = '';
        TransTitle = '';
    end

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

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

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

        local control = { 
            sep = A["EditorSeparator"] .. " ",
            namesep = (first_set(A["EditorNameSeparator"], A["NameSeparator"]) or "") .. " ",
            format = A['EditorFormat'],
            maximum = Maximum,
            lastauthoramp = LastAuthorAmp
        };

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

    local Cartography = "";
    local Scale = "";
    if config.CitationClass == "map" then
        if not is_set( Authors ) and is_set( PublisherName ) then
            Authors = PublisherName;
            PublisherName = "";
        end
        Cartography = A['Cartography'];
        if is_set( Cartography ) then
            Cartography = sepc .. " " .. wrap( 'cartography', Cartography, use_lowercase );
        end        
        Scale = A['Scale'];
        if is_set( Scale ) then
            Scale = sepc .. " " .. Scale;
        end        
    end
    
    if  not is_set(URL) and
        not is_set(ChapterURL) and
        not is_set(ArchiveURL) and
        not is_set(ConferenceURL) and
        not is_set(TranscriptURL) then
        
        -- Test if cite web or cite podcast |url= is missing or empty 
		if inArray(config.CitationClass, {"web","podcast"}) then	
			table.insert( z.message_tail, { seterror( 'cite_web_url', {}, true ) } );
		end
        
        -- Test if accessdate is given without giving a URL
        if is_set(AccessDate) then
            table.insert( z.message_tail, { seterror( 'accessdate_missing_url', {}, true ) } );
            AccessDate = '';
        end
        
        -- Test if format is given without giving a URL
        if is_set(Format) then
            Format = Format .. seterror( 'format_missing_url' );
        end
    end
    
    -- Test if citation has no title
    if  not is_set(Chapter) and
        not is_set(Title) and
        not is_set(Periodical) and
        not is_set(Conference) and
        not is_set(TransTitle) and
        not is_set(TransChapter) then
        table.insert( z.message_tail, { seterror( 'citation_missing_title', {}, true ) } );
    end
    
    Format = is_set(Format) and " (" .. Format .. ")" or "";
    
    local OriginalURL = URL
    DeadURL = DeadURL:lower();
    if is_set( ArchiveURL ) then
        if ( DeadURL ~= "no" ) then
            URL = ArchiveURL
            URLorigin = A:ORIGIN('ArchiveURL')
        end
    end
    
    -- Format chapter / article title
    if is_set(Chapter) and is_set(ChapterLink) then 
        Chapter = "[[" .. ChapterLink .. "|" .. Chapter .. "]]";
    end
    if is_set(Periodical) and is_set(Title) then
        Chapter = wrap( 'italic-title', Chapter );
        TransChapter = wrap( 'trans-italic-title', TransChapter );
    else
		Chapter = kern_quotes (Chapter);				-- if necessary, separate chapter title's leading and trailing quote marks from Module provided quote marks
        Chapter = wrap( 'quoted-title', Chapter );
        TransChapter = wrap( 'trans-quoted-title', TransChapter );
    end
    
    local TransError = ""
    if is_set(TransChapter) then
        if not is_set(Chapter) then
            TransError = " " .. seterror( 'trans_missing_chapter' );
        else
            TransChapter = " " .. TransChapter;
        end
    end
    
    Chapter = Chapter .. TransChapter;
    
    if is_set(Chapter) then
        if not is_set(ChapterLink) then
            if is_set(ChapterURL) then
                Chapter = externallink( ChapterURL, Chapter ) .. TransError;
                if not is_set(URL) then
                    Chapter = Chapter .. Format;
                    Format = "";
                end
            elseif is_set(URL) then 
                Chapter = externallink( URL, Chapter ) .. TransError .. Format;
                URL = "";
                Format = "";
            else
                Chapter = Chapter .. TransError;
            end            
        elseif is_set(ChapterURL) then
            Chapter = Chapter .. " " .. externallink( ChapterURL, nil, ChapterURLorigin ) .. 
                TransError;
        else
            Chapter = Chapter .. TransError;
        end
        Chapter = Chapter .. sepc .. " " -- with end-space
    elseif is_set(ChapterURL) then
        Chapter = " " .. externallink( ChapterURL, nil, ChapterURLorigin ) .. sepc .. " ";
    end        
    
    -- Format main title.
    if is_set(TitleLink) and is_set(Title) then
        Title = "[[" .. TitleLink .. "|" .. Title .. "]]"
    end
    
    if is_set(Periodical) then
		Title = kern_quotes (Title);				-- if necessary, separate title's leading and trailing quote marks from Module provided quote marks
        Title = wrap( 'quoted-title', Title );
        TransTitle = wrap( 'trans-quoted-title', TransTitle );
    elseif inArray(config.CitationClass, {"web","news","pressrelease","conference","podcast"}) and
            not is_set(Chapter) then
		Title = kern_quotes (Title);				-- if necessary, separate title's leading and trailing quote marks from Module provided quote marks
        Title = wrap( 'quoted-title', Title );
        TransTitle = wrap( 'trans-quoted-title', TransTitle );
    else
        Title = wrap( 'italic-title', Title );
        TransTitle = wrap( 'trans-italic-title', TransTitle );
    end
    
    TransError = "";
    if is_set(TransTitle) then
        if not is_set(Title) then
            TransError = " " .. seterror( 'trans_missing_title' );
        else
            TransTitle = " " .. TransTitle;
        end
    end
    
    Title = Title .. TransTitle;
    
    if is_set(Title) then
        if not is_set(TitleLink) and is_set(URL) then 
            Title = externallink( URL, Title ) .. TransError .. Format       
            URL = "";
            Format = "";
        else
            Title = Title .. TransError;
        end
    end
    
    if is_set(Place) then
        Place = " " .. wrap( 'written', Place, use_lowercase ) .. sepc .. " ";
    end
    
    if is_set(Conference) then
        if is_set(ConferenceURL) then
            Conference = externallink( ConferenceURL, Conference );
        end
        Conference = sepc .. " " .. Conference
    elseif is_set(ConferenceURL) then
        Conference = sepc .. " " .. externallink( ConferenceURL, nil, ConferenceURLorigin );
    end
    
    if not is_set(Position) then
        local Minutes = A['Minutes'];
        if is_set(Minutes) then
            Position = " " .. Minutes .. " " .. cfg.messages['minutes'];
        else
            local Time = A['Time'];
            if is_set(Time) then
                local TimeCaption = A['TimeCaption']
                if not is_set(TimeCaption) then
                    TimeCaption = cfg.messages['event'];
                    if sepc ~= '.' then
                        TimeCaption = TimeCaption:lower();
                    end
                end
                Position = " " .. TimeCaption .. " " .. Time;
            end
        end
    else
        Position = " " .. Position;
        At = '';
    end
    
    if not is_set(Page) then
        if is_set(Pages) then
            if is_set(Periodical) and
                not inArray(config.CitationClass, {"encyclopaedia","web","book","news","podcast"}) then
                Pages = ": " .. Pages;
            elseif tonumber(Pages) ~= nil then
                Pages = sepc .." " .. PPrefix .. Pages;
            else
                Pages = sepc .." " .. PPPrefix .. Pages;
            end
        end
    else
        if is_set(Periodical) and
            not inArray(config.CitationClass, {"encyclopaedia","web","book","news","podcast"}) then
            Page = ": " .. Page;
        else
            Page = sepc .." " .. PPrefix .. Page;
        end
    end
    
    At = is_set(At) and (sepc .. " " .. At) or "";
    Position = is_set(Position) and (sepc .. " " .. Position) or "";
    if config.CitationClass == 'map' then
        local Section = A['Section'];
        local Inset = A['Inset'];
        if first_set( Pages, Page, At ) ~= nil or sepc ~= '.' then
            if is_set( Section ) then
                Section = ", " .. wrap( 'section', Section, true );
            end
            if is_set( Inset ) then
                Inset = ", " .. wrap( 'inset', Inset, true );
            end
        else
            if is_set( Section ) then
                Section = sepc .. " " .. wrap( 'section', Section, use_lowercase );
                if is_set( Inset ) then
                    Inset = ", " .. wrap( 'inset', Inset, true );
                end
            elseif is_set( Inset ) then
                Inset = sepc .. " " .. wrap( 'inset', Inset, use_lowercase );
            end            
        end            
        At = At .. Section .. Inset;        
    end    

	--[[Look in the list of iso639-1 language codes to see if the value provided in the language parameter matches one of them.  If a match is found, 
	use that value; if not, then use the value that was provided with the language parameter.
	
	Categories are assigned in a manner similar to the {{xx icon}} templates - categorizes only mainspace citations and only when the language code is not 'en' (English).
	]]
	if is_set (Language) then
--		local name = mw.language.fetchLanguageName( Language:lower(), "en" );	-- experiment: this seems to return correct ISO 639-1 language names
		local name = cfg.iso639_1[Language:lower()];		-- get the language name if Language parameter has a valid iso 639-1 code
		if nil == name then
			Language=" " .. wrap( 'language', Language );	-- no match, use parameter's value
		else
			if 0 == this_page.namespace and 'en' ~= Language:lower() then	--found a match; is this page main / article space and English not the language?
				Language=" " .. wrap( 'language', name .. '[[Category:Articles with ' .. name .. '-language external links]]' );	-- in main space and not English: categorize
			else
				Language=" " .. wrap( 'language', name );	--not in mainspace or language is English so don't categorize
			end
		end
	else
		Language="";	-- language not specified so make sure this is an empty string;
	end

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

return z