Module:Citation/CS1

    From Nonbinary Wiki
    Revision as of 10:38, 12 October 2013 by m>Trappist the monk (ISSN error detection; Expand uncategorized namespaces; Reg/Sub required msg tweak; Trap coauthors without authors; Hide error messages;)

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

    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' );
    
    -- Contains a list of all recognized parameters
    local whitelist = mw.loadData( 'Module:Citation/CS1/Whitelist' );
    
    -- 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
    
    -- 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;
    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
    
    -- Checks that parameter name is valid using the whitelist
    function validate( name )
        name = tostring( name );
        
        -- Normal arguments
        if whitelist.basic_arguments[ name ] then
            return true;
        end
        
        -- Arguments with numbers in them
        name = name:gsub( "%d+", "#" );
        if whitelist.numbered_arguments[ name ] then
            return true;
        end
        
        -- Not found, argument not supported.
        return false
    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 " ",
            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 " ",
            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
    
    --[[
    Formats a PMC and checks for embargoed articles.  The embargo parameter takes a date for a value. If the embargo date is in the futue
    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'].link.
    
    The {{citation/core}} version of {{cite journal}} links the citation title (if url parameter is empty) when embargo date is in the past
    or when embargo parameter is missing or empty. That behavior is inconsistent with the behavior of other identifiers used in CS1 and is
    not supported here.
    ]]
    function pmc(id, embargo)
    	local handler = cfg.id_handlers['PMC'];
        
    	local text;
    	
    	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	--if embargo date is in the past then
    			text = externallinkid({link = handler.link, label = handler.label,			--ok to link to article
    				prefix=handler.prefix,id=id,separator=handler.separator, encode=handler.encode})
    		else
    			text="[[" .. handler.link .. "|" .. handler.label .. "]]:" .. handler.separator .. id;	--still embargoed so no external link
    		end
    	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})
    	end
    	return text
    end
    
    -- Formats a DOI and checks for DOI errors.
    function doi(id, inactive)
        local cat = ""
        local handler = cfg.id_handlers['DOI'];
        
        local text;
        if is_set(inactive) then
            text = "[[" .. handler.link .. "|" .. handler.label .. "]]:" .. id;
            table.insert( z.error_categories, "Pages with DOIs inactive since " .. selectyear(inactive) );        
            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 ( string.sub(id,1,3) ~= "10." ) then      
            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 clean_issn;
    	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 temp = 0;
    	local text;
    	local valid_issn = true;
    
    	id=id:gsub( "[%s-–]", "" );									-- strip spaces, hyphens, and ndashes from the issn
    	clean_issn=string.sub( id, 1, 4 ) .. "-" .. string.sub( id, 5 );	-- make a copy with a hyphen after 4 digits; use this version for display if issn validates
    
    	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
    		id = { id:byte(1, 8) };									-- table of individual bytes
    		for i, v in ipairs( id ) do								-- loop through all of the byte an calculate the checksum
    			if v == string.byte( "X" ) then						-- if checkdigit is X
    				temp = temp + 10*( 9 - i );						-- it represents 10 decimal
    			else
    				temp = temp + tonumber( string.char(v) )*(9-i);	
    			end
    		end
    		valid_issn = temp % 11 == 0;							-- checksum must be zero for valid issn
    	end
    
    	if true == valid_issn then
    		id = clean_issn;										-- if valid, use the cleaned-up version for the display			
    	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
    
    
    --[[
    Determines whether an 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
    
    -- Determines whether an ISBN string is valid
    function checkisbn( isbn_str )
        isbn_str = cleanisbn( isbn_str ):gsub( "-", "" );
        local len = isbn_str:len();
     
        if len ~= 10 and len ~= 13 then
            return false;
        end
     
        local temp = 0;
        if len == 10 then
            if isbn_str:match( "^%d*X?$" ) == nil then return false; end
            isbn_str = { isbn_str:byte(1, len) };
            for i, v in ipairs( isbn_str ) do
                if v == string.byte( "X" ) then
                    temp = temp + 10*( 11 - i );
                else
                    temp = temp + tonumber( string.char(v) )*(11-i);
                end
            end
            return temp % 11 == 0;
        else
            if isbn_str:match( "^%d*$" ) == nil then return false; end
            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  
    
    --[[
    Return the year portion of a date string, if possible.  
    Returns empty string if the argument can not be interpreted
    as a year.
    ]]
    function selectyear( str )
        -- Is the input a simple number?
        local num = tonumber( str ); 
        if num ~= nil and num > 0 and num < 2100 and num == math.floor(num) then
            return str;
        else
            -- Use formatDate to interpret more complicated formats
            local lang = mw.getContentLanguage();
            local good, result;
            good, result = pcall( lang.formatDate, lang, 'Y', str );
            if good then 
                return result;
            else
                -- extract year if the date uses seasons
                str=string.lower (str);
                local seasons={"winter", "spring", "summer", "fall", "autumn"};
                local date_string_split=mw.text.split (str, "[%s%-/–]");      -- split date string into parts; white space, hyphen, forward slash, and ndash are allowed separators
                local has_season=false;
                
                for n,season_value in ipairs(seasons) do                -- for each season ...
                    for n,split_value in ipairs(date_string_split) do   -- ... loop through date string values 
                        if split_value == season_value then             -- does the split value match the season value?
                            if has_season==false then                   -- found one. if this one is the first we've found ...
                                has_season=true;                        -- ... remember that we found a season
                            end
                        elseif has_season==true then                    -- if split_value isn't a season, and we've previously found a season ...
                            num = tonumber( split_value );              -- ... convert current split value to a number if we can
                            if num ~= nil and num > 0 and num < 2100 and num == math.floor(num) then    -- if it's a suitable number
                                return tostring( num );                                                 -- return it as a string
                            end -- if num
                        end -- if string.find
                    end -- for split value loop
                end -- season value loop
            end -- if good
        end -- if num
    end -- selectyear
    
    -- 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
                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 == '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 == '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 )
            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 foing 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 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'];
        
        if ( config.CitationClass == "encyclopaedia" ) then
            if not is_set(Chapter) then
                if not is_set(Title) then
                    Title = Periodical;
                    Periodical = '';
                else
                    Chapter = Title
                    TransChapter = TransTitle
                    Title = '';
                    TransTitle = '';
                end
            end
        end
    
        local Series = A['Series'];
        local Volume = A['Volume'];
        local Issue = A['Issue'];
        local Position = '';
        local Page, Pages, At, page_type;
        
        Page = A['Page'];
        Pages = hyphentodash( A['Pages'] );
        At = A['At'];
        
        if is_set(Page) then
            if is_set(Pages) or is_set(At) then
                Page = Page .. " " .. seterror('extra_pages');
                Pages = '';
                At = '';
            end
        elseif is_set(Pages) then
            if is_set(At) then
                Pages = Pages .. " " .. seterror('extra_pages');
                At = '';
            end
        end    
        
        local Edition = A['Edition'];
        local PublicationPlace = A['PublicationPlace']
        local Place = A['Place'];
        
        if not is_set(PublicationPlace) and is_set(Place) then
            PublicationPlace = Place;
        end
        
        if PublicationPlace == Place then Place = ''; end
        
        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'];
    
        local use_lowercase = ( sepc ~= '.' );
        local this_page = mw.title.getCurrentTitle();  --Also used for COinS and for language
        
        if not is_set(no_tracking_cats) then
            for k, v in pairs( cfg.uncategorized_namespaces ) do
                if this_page.nsText == v then
                    no_tracking_cats = "true";
                    break;
                end
            end
        end
    
        -- At this point fields may be nil if they weren't specified in the template use.  We can use that fact.
        
        -- Account for the oddity that is {{cite conference}}, before generation of COinS data.
        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.
        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
        
        -- 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(Date, Year, PublicationDate),
            ['Series'] = Series,
            ['Volume'] = Volume,
            ['Issue'] = Issue,
            ['Pages'] = first_set(Page, Pages, At),
            ['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(Date) then
            Date = Year;
            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
            end
        end
        
        if inArray(PublicationDate, {Date, Year}) then PublicationDate = ''; end
        if not is_set(Date) and is_set(PublicationDate) then
            Date = PublicationDate;
            PublicationDate = '';
        end
    
        -- Captures the value for Date prior to adding parens or other textual transformations
        local DateIn = Date;
        
        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 is called without giving a URL
            if ( config.CitationClass == "web" ) 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 = 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 = wrap( 'quoted-title', Title );
            TransTitle = wrap( 'trans-quoted-title', TransTitle );
        elseif inArray(config.CitationClass, {"web","news","pressrelease","conference"}) and
                not is_set(Chapter) then
            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"}) 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"}) 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 = 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 "";
        TitleType = is_set(TitleType) and (" (" .. TitleType .. ")") or "";
        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
        
        ------------------------------------ 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
        
        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 = "";
        elseif PostScript:lower() == "none" then
            PostScript = "";
        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"}) 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
    
        -- 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,-2); --Remove final seperator    
        end    
        
        text = safejoin( {text, PostScript}, sepc );
    
        -- Now enclose the whole thing in a <span/> element
        if not is_set(Year) then
            if is_set(DateIn) then
                Year = selectyear( DateIn );
            elseif is_set(PublicationDate) then
                Year = selectyear( PublicationDate );
            end
        end
        
        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 ] = Year;
                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()
        
        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