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Modul:Citation/CS1/sandbox

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local cs1 ={};

--[[--------------------------< F O R W A R D   D E C L A R A T I O N S >--------------------------------------
]]

local dates, year_date_check, reformat_dates, date_hyphen_to_dash                -- functions in Module:Citation/CS1/Date_validation

local is_set, in_array, substitute, error_comment, set_error, select_one,        -- functions in Module:Citation/CS1/Utilities
    add_maint_cat, wrap_style, safe_for_italics, remove_wiki_link;

local z ={};                                                                    -- tables in Module:Citation/CS1/Utilities

local extract_ids, extract_id_access_levels, build_id_list, is_embargoed;        -- functions in Module:Citation/CS1/Identifiers

local make_coins_title, get_coins_pages, COinS;                                    -- functions in Module:Citation/CS1/COinS

local cfg = {};                                                                    -- table of configuration tables that are defined in Module:Citation/CS1/Configuration
local whitelist = {};                                                            -- table of tables listing valid template parameter names; defined in Module:Citation/CS1/Whitelist


--[[--------------------------< P A G E   S C O P E   V A R I A B L E S >--------------------------------------

delare variables here that have page-wide scope that are not brought in from other modules; thatare created here
and used here

]]

local added_deprecated_cat;                                                        -- boolean flag so that the category is added only once
local added_prop_cats = {};                                                        -- list of property categories that have been added to z.properties_cats
local added_vanc_errs;                                                            -- boolean flag so we only emit one Vancouver error / category

local Frame;                                                                    -- holds the module's frame table


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

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

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

]]

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

--[[--------------------------< A D D _ P R O P _ C A T >--------------------------------------------------------

Adds a category to z.properties_cats using names from the configuration file with additional text if any.

added_prop_cats is a table declared in page scope variables above

]]

local function add_prop_cat (key, arguments)
    if not added_prop_cats [key] then
        added_prop_cats [key] = true;                                            -- note that we've added this category
        table.insert( z.properties_cats, substitute (cfg.prop_cats [key], arguments));        -- make name then add to table
    end
end

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

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

added_vanc_errs is a boolean declared in page scope variables above

]]

local function add_vanc_error (source)
    if not added_vanc_errs then
        added_vanc_errs = true;                                                    -- note that we've added this category
        table.insert( z.message_tail, { set_error( 'vancouver', {source}, true ) } );
    end
end


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

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

returns true if it does, else false

]]

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


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

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

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

rfc952 (modified by rfc 1123) requires the first and last character of a hostname to be a letter or a digit.  Between
the first and last characters the name may use letters, digits, and the hyphen.

Also allowed are IPv4 addresses. IPv6 not supported

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

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

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

]=]

local function is_domain_name (domain)
    if not domain then
        return false;                                                            -- if not set, abandon
    end
    
    domain = domain:gsub ('^//', '');                                            -- strip '//' from domain name if present; done here so we only have to do it once
    
    if not domain:match ('^[%a%d]') then                                        -- first character must be letter or digit
        return false;
    end
                                                                                -- Do most common case first
    if domain:match ('%f[%a%d][%a%d][%a%d%-]+[%a%d]%.%a%a+$') then                -- three or more character hostname.hostname or hostname.tld
        return true;
    elseif domain:match ('%f[%a%d][%a%d][%a%d%-]+[%a%d]%.xn%-%-[%a%d]+$') then    -- internationalized domain name with ACE prefix
        return true;
    elseif domain:match ('%f[%a%d][%a%d]%.org$') then                            -- one character .org hostname
        return true;
    elseif domain:match ('%f[%a][qxz]%.com$') then                                -- assigned one character .com hostname (x.com times out 2015-12-10)
        return true;
    elseif domain:match ('%f[%a][iq]%.net$') then                                -- assigned one character .net hostname (q.net registered but not active 2015-12-10)
        return true;
    elseif domain:match ('%f[%a%d][%a%d]%.%a%a$') then                            -- one character hostname and cctld (2 chars)
        return true;
    elseif domain:match ('%f[%a%d][%a%d][%a%d]%.%a%a+$') then                    -- two character hostname and tld
        return true;
    elseif domain:match ('^%d%d?%d?%.%d%d?%d?%.%d%d?%d?%.%d%d?%d?') then        -- IPv4 address
        return true;
    else
        return false;
    end
end


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

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

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

]]

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


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

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

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

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

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

Strip off any port and path;

]]

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

    if url_str:match ('^//%S*') then                                            -- if there is what appears to be a protocol relative url
        domain = url_str:match ('^//(%S*)')
    elseif url_str:match ('%S-:/*%S+') then                                        -- if there is what appears to be a scheme, optional authority indicator, and domain name
        scheme, authority, domain = url_str:match ('(%S-:)(/*)(%S+)');            -- extract the scheme, authority indicator, and domain portions
        authority = authority:gsub ('//', '', 1);                                -- replace place 1 pair of '/' with nothing;
        if is_set(authority) then                                                -- if anything left (1 or 3+ '/' where authority should be) then
            return scheme;                                                        -- return scheme only making domain nil which will cause an error message
        end
        domain = domain:gsub ('(%a):%d+', '%1');                                -- strip port number if present
    end
    
    return scheme, domain;
end


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

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

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

returns false when the value contains any of these characters.

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

]]

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

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

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

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

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

]]

local function link_title_ok (link, lorig, title, torig)
local orig;

    if is_set (link) then                                                         -- don't bother if <param>-link doesn't have a value
        if not link_param_ok (link) then                                        -- check |<param>-link= markup
            orig = lorig;                                                        -- identify the failing link parameter
        elseif title:find ('%[%[') then                                            -- check |title= for wikilink markup
            orig = torig;                                                        -- identify the failing |title= parameter
        end
    end

    if is_set (orig) then
        table.insert( z.message_tail, { set_error( 'bad_paramlink', orig)});    -- url or wikilink in |title= with |title-link=;
    end
end


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

Determines whether a URL string appears to be valid.

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

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

]]

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

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


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

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

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

]=]

local function is_parameter_ext_wikilink (value)
local scheme, domain;

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

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


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

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

]]

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


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

Escape sequences for content that will be used for URL descriptions

]]

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

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

Format an external link with error checking

]]

local function external_link( URL, label, source, access)
    local error_str = "";
    local domain;
    local path;
    local base_url;
    
    if not is_set( label ) then
        label = URL;
        if is_set( source ) then
            error_str = set_error( 'bare_url_missing_title', { wrap_style ('parameter', source) }, false, " " );
        else
            error( cfg.messages["bare_url_no_origin"] );
        end            
    end
    if not check_url( URL ) then
        error_str = set_error( 'bad_url', {wrap_style ('parameter', source)}, false, " " ) .. error_str;
    end
    
    domain, path = URL:match ('^([/%.%-%+:%a%d]+)([/%?#].*)$');                    -- split the url into scheme plus domain and path
    if path then                                                                -- if there is a path portion
        path = path:gsub ('[%[%]]', {['[']='%5b',[']']='%5d'});                    -- replace '[' and ']' with their percent encoded values
        URL=domain..path;                                                        -- and reassemble
    end
    
    if is_set (access) then                                                        -- access level (subscription, registration, limited)
        local label_head = '';
        local label_tail;
        local markup = '';                                                        -- can't start a span inside italic markup and end it outside the italic markup

        label = safe_for_url (label);                                            -- replace square brackets and newlines (is this necessary? already done above?)
        if label:match ("(.*)%s+(.+)('''?)$") then                                -- for italicized titles (cite book, etc)
            label_head, label_tail, markup = label:match ("(.*)%s+(.+)('''?)$");    -- split the label at the right-most space; separate the markup
        elseif label:match ("(.*)%s+(.+)$") then                                -- for upright titles (journal, news, magazine, etc)
            label_head, label_tail = label:match ("(.*)%s+(.+)$");                -- split the label at the right-most space; no markup
        elseif label:match ("(.+)('''?)$") then                                    -- single word label with markup
            label_tail, markup = label:match ("(.+)('''?)$");                    -- save label text as label tail; separate the markup
        else
            label_tail = label;
        end

        base_url = table.concat (
            {
            '<span class="plainlinks">[',                                        -- opening css
            URL,                                                                -- the url
            ' ',                                                                -- the required space
            label_head,                                                            -- all but the last word of the label
            ' <span class="nowrap">',                                            -- nowrap css for the last word and the signal icon
            label_tail,                                                            -- last (or only) word of the label inside the span
            '<span style="padding-left:0.15em">',                                -- signal spacing css
            cfg.presentation[access],                                            -- the appropriate icon
            '</span></span>',                                                    -- close signal spacing and nowrap spans
            markup,                                                                -- insert italic markup if any
            ']</span>'                                                            -- close the plain links span
            });
    else
        base_url = table.concat({ "[", URL, " ", safe_for_url( label ), "]" });    -- no signal markup
    end
    
    return table.concat({ base_url, error_str });
end


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

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

added_deprecated_cat is a boolean declared in page scope variables above

]]

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

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

Apply kerning to open the space between the quote mark provided by the Module and a leading or trailing quote mark contained in a |title= or |chapter= parameter's value.
This function will positive kern either single or double quotes:
    "'Unkerned title with leading and trailing single quote marks'"
    " 'Kerned title with leading and trailing single quote marks' " (in real life the kerning isn't as wide as this example)
Double single quotes (italic or bold wikimarkup) are not kerned.

Replaces unicode quotemarks with typewriter quote marks regardless of the need for kerning.

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

]]

local function kern_quotes (str)
    local cap='';
    local cap2='';
                                                                                -- TODO: move this elswhere so that all title-holding elements get these quote marks replaced?
--    str= mw.ustring.gsub (str, '[“”]', '\"');                                    -- replace “” (U+201C & U+201D) with " (typewriter double quote mark)
--    str= mw.ustring.gsub (str, '[‘’]', '\'');                                    -- replace ‘’ (U+2018 & U+2019) with ' (typewriter single quote mark)
    
    cap, cap2 = str:match ("^([\"\'])([^\'].+)");                                -- match leading double or single quote but not double single quotes
    if is_set (cap) then
        str = substitute (cfg.presentation['kern-left'], {cap, cap2});
    end

    cap, cap2 = str:match ("^(.+[^\'])([\"\'])$")
    if is_set (cap) then
        str = substitute (cfg.presentation['kern-right'], {cap, cap2});
    end
    return str;
end

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

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

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

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

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

Supports |script-title= and |script-chapter=

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

local function format_script_value (script_value)
    local lang='';                                                                -- initialize to empty string
    local name;
    if script_value:match('^%l%l%s*:') then                                        -- if first 3 non-space characters are script language prefix
        lang = script_value:match('^(%l%l)%s*:%s*%S.*');                        -- get the language prefix or nil if there is no script
        if not is_set (lang) then
            return '';                                                            -- script_value was just the prefix so return empty string
        end
                                                                                -- if we get this far we have prefix and script
        name = mw.language.fetchLanguageName( lang, "en" );                        -- get language name so that we can use it to categorize
        if is_set (name) then                                                    -- is prefix a proper ISO 639-1 language code?
            script_value = script_value:gsub ('^%l%l%s*:%s*', '');                -- strip prefix from script
                                                                                -- is prefix one of these language codes?
            if in_array (lang, cfg.script_lang_codes) then
                add_prop_cat ('script_with_name', {name, lang})
            else
                add_prop_cat ('script')
            end
            lang = ' lang="' .. lang .. '" ';                                    -- convert prefix into a lang attribute
        else
            lang = '';                                                            -- invalid so set lang to empty string
        end
    end
    script_value = substitute (cfg.presentation['bdi'], {lang, script_value});    -- isolate in case script is rtl

    return script_value;
end

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

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

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


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

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

]]

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


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

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

]]

local function format_chapter_title (scriptchapter, chapter, transchapter, chapterurl, chapter_url_source, no_quotes)
    local chapter_error = '';
    
    if not is_set (chapter) then
        chapter = '';                                                            -- to be safe for concatenation
    else
        if false == no_quotes then
            chapter = kern_quotes (chapter);                                        -- if necessary, separate chapter title's leading and trailing quote marks from Module provided quote marks
            chapter = wrap_style ('quoted-title', chapter);
        end
    end

    chapter = script_concatenate (chapter, scriptchapter)                        -- <bdi> tags, lang atribute, categorization, etc; must be done after title is wrapped

    if is_set (transchapter) then
        transchapter = wrap_style ('trans-quoted-title', transchapter);
        if is_set (chapter) then
            chapter = chapter ..  ' ' .. transchapter;
        else                                                                    -- here when transchapter without chapter or script-chapter
            chapter = transchapter;                                                --
            chapter_error = ' ' .. set_error ('trans_missing_title', {'chapter'});
        end
    end

    if is_set (chapterurl) then
        chapter = external_link (chapterurl, chapter, chapter_url_source, nil);        -- adds bare_url_missing_title error if appropriate
    end

    return chapter .. chapter_error;
end

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

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

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

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

Detects but ignores the character pattern that results from the transclusion of {{'}} templates.

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

]]

local function has_invisible_chars (param, v)
    local position = '';                                                        -- position of invisible char or starting position of stripmarker
    local dummy;                                                                -- end of matching string; not used but required to hold end position when a capture is returned
    local capture;                                                                -- used by stripmarker detection to hold name of the stripmarker
    local i=1;
    local stripmarker, apostrophe;
    
    capture = string.match (v, '[%w%p ]*');                                        -- Test for values that are simple ASCII text and bypass other tests if true
    if capture == v then                                                        -- if same there are no unicode characters
        return;
    end

    while cfg.invisible_chars[i] do
        local char=cfg.invisible_chars[i][1]                                    -- the character or group name
        local pattern=cfg.invisible_chars[i][2]                                    -- the pattern used to find it
        position, dummy, capture = mw.ustring.find (v, pattern)                    -- see if the parameter value contains characters that match the pattern
        
        if position then
            if 'nowiki' == capture or 'math' == capture then                     -- nowiki, math stripmarker (not an error condition)
                stripmarker = true;                                                -- set a flag
            elseif true == stripmarker and 'delete' == char then                -- because stripmakers begin and end with the delete char, assume that we've found one end of a stripmarker
                position = nil;                                                    -- unset
            else
                local err_msg;
                if capture then
                    err_msg = capture .. ' ' .. char;
                else
                    err_msg = char .. ' ' .. 'character';
                end

                table.insert( z.message_tail, { set_error( 'invisible_char', {err_msg, wrap_style ('parameter', param), position}, true ) } );    -- add error message
                return;                                                            -- and done with this parameter
            end
        end
        i=i+1;                                                                    -- bump our index
    end
end


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

Argument wrapper.  This function provides support for argument mapping defined in the configuration file so that
multiple names can be transparently aliased to single internal variable.

]]

local function argument_wrapper( args )
    local origin = {};
    
    return setmetatable({
        ORIGIN = function( self, k )
            local dummy = self[k]; --force the variable to be loaded.
            return origin[k];
        end
    },
    {
        __index = function ( tbl, k )
            if origin[k] ~= nil then
                return nil;
            end
            
            local args, list, v = args, cfg.aliases[k];
            
            if type( list ) == 'table' then
                v, origin[k] = select_one( 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

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

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

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

--local function validate( name )
local function validate( name, cite_class )
    local name = tostring( name );
    local state;
    
    if in_array (cite_class, {'arxiv', 'biorxiv', 'citeseerx'}) then                -- limited parameter sets allowed for these templates
        state = whitelist.limited_basic_arguments[ name ];
        if true == state then return true; end                                    -- valid actively supported parameter
        if false == state then
            deprecated_parameter (name);                                        -- parameter is deprecated but still supported
            return true;
        end

        if 'arxiv' == cite_class then                                            -- basic parameters unique to these templates
            state = whitelist.arxiv_basic_arguments[name];
        end
        if 'biorxiv' == cite_class then
            state = whitelist.biorxiv_basic_arguments[name];
        end
        if 'citeseerx' == cite_class then
            state = whitelist.citeseerx_basic_arguments[name];
        end

        if true == state then return true; end                                    -- valid actively supported parameter
        if false == state then
            deprecated_parameter (name);                                        -- parameter is deprecated but still supported
            return true;
        end
                                                                                -- limited enumerated parameters list
        name = name:gsub( "%d+", "#" );                                            -- replace digit(s) with # (last25 becomes last#)
        state = whitelist.limited_numbered_arguments[ name ];
        if true == state then return true; end                                    -- valid actively supported parameter
        if false == state then
            deprecated_parameter (name);                                        -- parameter is deprecated but still supported
            return true;
        end

        return false;                                                            -- not supported because not found or name is set to nil
    end                                                                            -- end limited parameter-set templates
        
    state = whitelist.basic_arguments[ name ];                                    -- all other templates; all normal parameters allowed
                                            
    if true == state then return true; end                                        -- valid actively supported parameter
    if false == state then
        deprecated_parameter (name);                                            -- parameter is deprecated but still supported
        return true;
    end
                                                                                -- all enumerated parameters allowed
    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 (name);                                            -- parameter is deprecated but still supported
        return true;
    end
    
    return false;                                                                -- not supported because not found or name is set to nil
end


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

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

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

]]

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

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

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

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

]]

local function set_titletype (cite_class, title_type)
    if 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

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


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

Converts a hyphen to a dash

]]

local function hyphen_to_dash( str )
    if not is_set(str) or str:match( "[%[%]{}<>]" ) ~= nil then
        return str;
    end    
    return str:gsub( '-', '–' );
end


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

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

]]

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

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


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

returns true is suffix is properly formed Jr, Sr, or ordinal in the range 2–9.  Puncutation not allowed.

]]

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

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

For Vancouver Style, author/editor names are supposed to be rendered in Latin (read ASCII) characters.  When a name
uses characters that contain diacritical marks, those characters are to converted to the corresponding Latin character.
When a name is written using a non-Latin alphabet or logogram, that name is to be transliterated into Latin characters.
These things are not currently possible in this module so are left to the editor to do.

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

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

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

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

]]

local function is_good_vanc_name (last, first)
    local first, suffix = first:match ('(.-),?%s*([%dJS][%drndth]+)%.?$') or first;        -- if first has something that looks like a generational suffix, get it

    if is_set (suffix) then
        if not is_suffix (suffix) then
            add_vanc_error ('suffix');
            return false;                                                        -- not a name with an appropriate suffix
        end
    end
    if nil == mw.ustring.find (last, "^[A-Za-z\195\128-\195\150\195\152-\195\182\195\184-\198\191\199\132-\201\143%-%s%']*$") or
        nil == mw.ustring.find (first, "^[A-Za-z\195\128-\195\150\195\152-\195\182\195\184-\198\191\199\132-\201\143%-%s%'%.]*$") then
            add_vanc_error ('non-Latin character');
            return false;                                                        -- not a string of latin characters; Vancouver requires Romanization
    end;
    return true;
end

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

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

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

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

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

]]

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

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

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


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

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

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

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

Formats a list of people (e.g. authors / editors)

]]

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

    if 'vanc' == format then                                                    -- Vancouver-like author/editor name styling?
        sep = ',';                                                                -- name-list separator between authors is a comma
        namesep = ' ';                                                            -- last/first separator is a space
    elseif 'mla' == control.mode then
        sep = ',';                                                                -- name-list separator between authors is a comma
        namesep = ', '                                                            -- last/first separator is <comma><space>
    else
        sep = ';'                                                                -- name-list separator between authors is a semicolon
        namesep = ', '                                                            -- last/first separator is <comma><space>
    end
    
    if sep:sub(-1,-1) ~= " " then sep = sep .. " " end
    if is_set (maximum) and maximum < 1 then return "", 0; end                    -- returned 0 is for EditorCount; not used for authors
    
    for i,person in ipairs(people) do
        if is_set(person.last) then
            local mask = person.mask
            local one
            local sep_one = sep;
            if is_set (maximum) 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 'mla' == control.mode then
                        if i == 1 then                                            -- for mla
                            one = one .. namesep .. first;                        -- first name last, first
                        else                                                    -- all other names
                            one = first .. ' ' .. one;                            -- first last
                        end
                    else
                        if ( "vanc" == format ) then                                -- if vancouver format
                            one = one:gsub ('%.', '');                                -- remove periods from surnames (http://www.ncbi.nlm.nih.gov/books/NBK7271/box/A35029/)
                            if not person.corporate and is_good_vanc_name (one, first) then                    -- and name is all Latin characters; corporate authors not tested
                                first = reduce_to_initials(first)                    -- attempt to convert first name(s) to initials
                            end
                        end
                        one = one .. namesep .. first;
                    end
                end
                if is_set(person.link) and person.link ~= control.page_name then
                    one = "[[" .. person.link .. "|" .. one .. "]]"                -- link author/editor if this page is not the author's/editor's page
                end
            end
            table.insert( text, one )
            table.insert( text, sep_one )
        end
    end

    local count = #text / 2;                                                    -- (number of names + number of separators) divided by 2
    if count > 0 then
        if count > 1 and is_set(lastauthoramp) and not etal then
            if 'mla' == control.mode then
                text[#text-2] = ", and ";                                        -- replace last separator with ', and ' text
            else
                text[#text-2] = " & ";                                            -- replace last separator with ampersand text
            end
        end
        text[#text] = nil;                                                        -- erase the last separator
    end
    
    local result = table.concat(text)                                            -- construct list
    if etal and is_set (result) then                                            -- etal may be set by |display-authors=etal but we might not have a last-first list
        result = result .. sep .. ' ' .. cfg.messages['et al'];                    -- we've go a last-first list and etal so add et al.
    end
    
    return result, count
end

--[[--------------------------< A N C H O R _ I D >------------------------------------------------------------

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

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

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


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

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

This function never sets the flag to false but returns it's previous state because it may have been set by
previous passes through this function or by the parameters |display-authors=etal or |display-editors=etal

]]

local function name_has_etal (name, etal, nocat)

    if is_set (name) then                                                        -- name can be nil in which case just return
        local etal_pattern = "[;,]? *[\"']*%f[%a][Ee][Tt] *[Aa][Ll][%.\"']*$"    -- variations on the 'et al' theme
        local others_pattern = "[;,]? *%f[%a]and [Oo]thers";                    -- and alternate to et al.
        
        if name:match (etal_pattern) then                                        -- variants on et al.
            name = name:gsub (etal_pattern, '');                                -- if found, remove
            etal = true;                                                        -- set flag (may have been set previously here or by |display-authors=etal)
            if not nocat then                                                    -- no categorization for |vauthors=
                add_maint_cat ('etal');                                            -- and add a category if not already added
            end
        elseif name:match (others_pattern) then                                    -- if not 'et al.', then 'and others'?
            name = name:gsub (others_pattern, '');                                -- if found, remove
            etal = true;                                                        -- set flag (may have been set previously here or by |display-authors=etal)
            if not nocat then                                                    -- no categorization for |vauthors=
                add_maint_cat ('etal');                                            -- and add a category if not already added
            end
        end
    end
    return name, etal;                                                            --
end


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

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

]]

local function name_has_ed_markup (name, list_name)
    local _, pattern;
    local patterns = {                                                            -- these patterns match annotations at end of name
        '%f[%(%[][%(%[]%s*[Ee][Dd][Ss]?%.?%s*[%)%]]?$',                            -- (ed) or (eds): leading '(', case insensitive 'ed', optional 's', '.' and/or ')'
        '[,%.%s]%f[e]eds?%.?$',                                                    -- ed or eds: without '('or ')'; case sensitive (ED could be initials Ed could be name)
        '%f[%(%[][%(%[]%s*[Ee][Dd][Ii][Tt][Oo][Rr][Ss]?%.?%s*[%)%]]?$',            -- (editor) or (editors): leading '(', case insensitive, optional '.' and/or ')'
        '[,%.%s]%f[Ee][Ee][Dd][Ii][Tt][Oo][Rr][Ss]?%.?$',                        -- editor or editors: without '('or ')'; case insensitive
        
                                                                                -- these patterns match annotations at beginning of name
        '^eds?[%.,;]',                                                            -- ed. or eds.: lower case only, optional 's', requires '.'
        '^[%(%[]%s*[Ee][Dd][Ss]?%.?%s*[%)%]]',                                    -- (ed) or (eds): also sqare brackets, case insensitive, optional 's', '.'
        '^[%(%[]?%s*[Ee][Dd][Ii][Tt][Oo][Rr][Ss]?%A',                            -- (editor or (editors: also sq brackets, case insensitive, optional brackets, 's'
        '^[%(%[]?%s*[Ee][Dd][Ii][Tt][Ee][Dd]%A',                                -- (edited: also sq brackets, case insensitive, optional brackets

        }

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


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

Evaluates the content of author and editor (surnames only) parameters for multiple names.  Multiple names are
indicated if there is more than one comma and or semicolon.  If found, the function adds the multiple name
(author or editor) maintenance category.

]]

local function name_has_mult_names (name, list_name)
local count, _;
    if is_set (name) then
        _, count = name:gsub ('[;,]', '');                                        -- count the number of separator-like characters
        
        if 1 < count then                                                        -- param could be |author= or |editor= so one separator character is acceptable
            add_maint_cat ('mult_names', cfg.special_case_translation [list_name]);    -- more than one separator indicates multiple names so add a maint cat for this template
        end
    end
    return name;                                                                -- and done
end


--[[--------------------------< N A M E _ C H E C K S >--------------------------------------------------------
This function calls various name checking functions used to validate the content of the various name-holding
parameters.

]]

local function name_checks (last, first, list_name)
    if is_set (last) then
        if last:match ('^%(%(.*%)%)$') then                                        -- if wrapped in doubled parentheses, accept as written
            last = last:match ('^%(%((.*)%)%)$');                                -- strip parens
        else
            last = name_has_mult_names (last, list_name);                        -- check for multiple names in the parameter (last only)
            last = name_has_ed_markup (last, list_name);                        -- check for extraneous 'editor' annotation
        end
    end
    if is_set (first) then
        if first:match ('^%(%(.*%)%)$') then                                    -- if wrapped in doubled parentheses, accept as written
            first = first:match ('^%(%((.*)%)%)$');                                -- strip parens
        else
            first = name_has_ed_markup (first, list_name);                        -- check for extraneous 'editor' annotation
        end
    end
    return last, first;                                                            -- done
    end


--[[--------------------------< E X T R A C T _ N A M E S >----------------------------------------------------
Gets name list from the input arguments

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

This function emits an error message when there is a |firstn= without a matching |lastn=.  When there are 'holes' in the list of last names, |last1= and |last3=
are present but |last2= is missing, an error message is emitted. |lastn= is not required to have a matching |firstn=.

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

]]

local function extract_names(args, list_name)
    local names = {};            -- table of names
    local last;                    -- individual name components
    local first;
    local link;
    local mask;
    local i = 1;                -- loop counter/indexer
    local n = 1;                -- output table indexer
    local count = 0;            -- used to count the number of times we haven't found a |last= (or alias for authors, |editor-last or alias for editors)
    local etal=false;            -- return value set to true when we find some form of et al. in an author parameter

    local err_msg_list_name = list_name:match ("(%w+)List") .. 's list';        -- modify AuthorList or EditorList for use in error messages if necessary
    while true do
        last = select_one( args, cfg.aliases[list_name .. '-Last'], 'redundant_parameters', i );        -- search through args for name components beginning at 1
        first = select_one( args, cfg.aliases[list_name .. '-First'], 'redundant_parameters', i );
        link = select_one( args, cfg.aliases[list_name .. '-Link'], 'redundant_parameters', i );
        mask = select_one( args, cfg.aliases[list_name .. '-Mask'], 'redundant_parameters', i );

        last, etal = name_has_etal (last, etal, false);                            -- find and remove variations on et al.
        first, etal = name_has_etal (first, etal, false);                        -- find and remove variations on et al.
        last, first= name_checks (last, first, list_name);                        -- multiple names, extraneous annotation, etc checks
        
        if first and not last then                                                -- if there is a firstn without a matching lastn
            table.insert( z.message_tail, { set_error( 'first_missing_last', {err_msg_list_name, i}, true ) } );    -- add this error message
        elseif not first and not last then                                        -- if both firstn and lastn aren't found, are we done?
            count = count + 1;                                                    -- number of times we haven't found last and first
            if 2 <= count then                                                    -- two missing names and we give up
                break;                                                            -- normal exit or there is a two-name hole in the list; can't tell which
            end
        else                                                                    -- we have last with or without a first
            link_title_ok (link, list_name:match ("(%w+)List"):lower() .. '-link' .. i, last, list_name:match ("(%w+)List"):lower() .. '-last' .. i);    -- check for improper wikimarkup

            names[n] = {last = last, first = first, link = link, mask = mask, corporate=false};    -- add this name to our names list (corporate for |vauthors= only)
            n = n + 1;                                                            -- point to next location in the names table
            if 1 == count then                                                    -- if the previous name was missing
                table.insert( z.message_tail, { set_error( 'missing_name', {err_msg_list_name, i-1}, true ) } );        -- add this error message
            end
            count = 0;                                                            -- reset the counter, we're looking for two consecutive missing names
        end
        i = i + 1;                                                                -- point to next args location
    end
    
    return names, etal;                                                            -- all done, return our list of names
end

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

Validates language names provided in |language= parameter if not an ISO639-1 or 639-2 code.

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

mw.language.fetchLanguageNames(<local wiki language>, 'all') return a list of languages that in some cases may include
extensions. For example, code 'cbk-zam' and its associated name 'Chavacano de Zamboanga' (MediaWiki does not support
code 'cbk' or name 'Chavacano'.

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

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

]]

local function get_iso639_code (lang, this_wiki_code)
    if 'bangla' == lang:lower() then                                            -- special case related to Wikimedia remap of code 'bn' at mw:Extension:CLDR
        return 'Bengali', 'bn';                                                    -- make sure rendered version is properly capitalized
    end

    local languages = mw.language.fetchLanguageNames(this_wiki_code, 'all')        -- get a list of language names known to Wikimedia
                                                                                -- ('all' is required for North Ndebele, South Ndebele, and Ojibwa)
    local langlc = mw.ustring.lower(lang);                                        -- lower case version for comparisons
    
    for code, name in pairs(languages) do                                        -- scan the list to see if we can find our language
        if langlc == mw.ustring.lower(name) then
            if 2 ~= code:len() and 3 ~= code:len() then                            -- two- or three-character codes only; extensions not supported
                return name;                                                    -- so return the name but not the code
            end
            return name, code;                                                    -- found it, return name to ensure proper capitalization and the the code
        end
    end
    return lang;                                                                -- not valid language; return language in original case and nil for the code
end


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

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

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

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

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

]]

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

    local this_wiki = mw.getContentLanguage();                                    -- get a language object for this wiki
    local this_wiki_code = this_wiki:getCode()                                    -- get this wiki's language code
    local this_wiki_name = mw.language.fetchLanguageName(this_wiki_code, this_wiki_code);    -- get this wiki's language name

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

    for _, lang in ipairs (names_table) do                                        -- reuse lang

        if lang:match ('^%a%a%-') then                                            -- strip ietf language tags from code; TODO: is there a need to support 3-char with tag?
            lang = lang:match ('(%a%a)%-')                                        -- keep only 639-1 code portion to lang; TODO: do something with 3166 alpha 2 country code?
        end
        if 2 == lang:len() or 3 == lang:len() then                                -- if two-or three-character code
            name = mw.language.fetchLanguageName( lang:lower(), this_wiki_code);    -- get language name if |language= is a proper code
        end
    
        if is_set (name) then                                                    -- if |language= specified a valid code
            code = lang:lower();                                                -- save it
        else
            name, code = get_iso639_code (lang, this_wiki_code);                -- attempt to get code from name (assign name here so that we are sure of proper capitalization)
        end
    
        if is_set (code) then                                                    -- only 2- or 3-character codes
            if 'bn' == code then name = 'Bengali' end;                            -- override wikimedia when code is 'bn'
            if this_wiki_code ~= code then                                        -- when the language is not the same as this wiki's language
                if 2 == code:len() then                                            -- and is a two-character code
                    add_prop_cat ('foreign_lang_source', {name, code})            -- categorize it
                else                                                            -- or is a recognized language (but has a three-character code)
                    add_prop_cat ('foreign_lang_source_2', {code})                -- categorize it differently TODO: support mutliple three-character code categories per cs1|2 template
                end
            end
        else
            add_maint_cat ('unknown_lang');                                        -- add maint category if not already added
        end
        
        table.insert (language_list, name);
        name = '';                                                                -- so we can reuse it
    end
    
    code = #language_list                                                        -- reuse code as number of languages in the list
    if 2 >= code then
        name = table.concat (language_list, ' and ')                            -- insert '<space>and<space>' between two language names
    elseif 2 < code then
        language_list[code] = 'and ' .. language_list[code];                    -- prepend last name with 'and<space>'
        name = table.concat (language_list, ', ')                                -- and concatenate with '<comma><space>' separators
    end
    if this_wiki_name == name then
        return '';                                                                -- if one language and that language is this wiki's return an empty string (no annotation)
    end
    return (" " .. wrap_msg ('language', name));                                -- otherwise wrap with '(in ...)'
    --[[ TODO: should only return blank or name rather than full list
    so we can clean up the bunched parenthetical elements Language, Type, Format
    ]]
end

--[[--------------------------< S E T _ C S 1 _ S T Y L E >----------------------------------------------------

Set style settings for CS1 citation templates. Returns separator and postscript settings

]]

local function set_cs1_style (ps)
    if not is_set (ps) then                                                        -- unless explicitely set to something
        ps = '.';                                                                -- terminate the rendered citation with a period
    end
    return '.', ps;                                                                -- separator is a full stop
end

--[[--------------------------< S E T _ C S 2 _ S T Y L E >----------------------------------------------------

Set style settings for CS2 citation templates. Returns separator, postscript, ref settings

]]

local function set_cs2_style (ps, ref)
    if not is_set (ps) then                                                        -- if |postscript= has not been set, set cs2 default
        ps = '';                                                                -- make sure it isn't nil
    end
    if not is_set (ref) then                                                    -- if |ref= is not set
        ref = "harv";                                                            -- set default |ref=harv
    end
    return ',', ps, ref;                                                        -- separator is a comma
end

--[[--------------------------< G E T _ S E T T I N G S _ F R O M _ C I T E _ C L A S S >----------------------

When |mode= is not set or when its value is invalid, use config.CitationClass and parameter values to establish
rendered style.

]]

local function get_settings_from_cite_class (ps, ref, cite_class)
    local sep;
    if (cite_class == "citation") then                                            -- for citation templates (CS2)
        sep, ps, ref = set_cs2_style (ps, ref);
    else                                                                        -- not a citation template so CS1
        sep, ps = set_cs1_style (ps);
    end

    return sep, ps, ref                                                            -- return them all
end

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

Establish basic style settings to be used when rendering the citation.  Uses |mode= if set and valid or uses
config.CitationClass from the template's #invoke: to establish style.

]]

local function set_style (mode, ps, ref, cite_class)
    local sep;
    if 'cs2' == mode then                                                        -- if this template is to be rendered in CS2 (citation) style
        sep, ps, ref = set_cs2_style (ps, ref);
    elseif 'cs1' == mode then                                                    -- if this template is to be rendered in CS1 (cite xxx) style
        sep, ps = set_cs1_style (ps);
    elseif 'mla' == mode then                                                    -- if this template is to be rendered in mla style use cs1 for bot cs1 & cs2 templates
        sep, ps = set_cs1_style (ps);
    else                                                                        -- anything but cs1 or cs2
        sep, ps, ref = get_settings_from_cite_class (ps, ref, cite_class);        -- get settings based on the template's CitationClass
    end
    if 'none' == ps:lower() then                                                -- if assigned value is 'none' then
        ps = '';                                                                -- set to empty string
    end
    
    return sep, ps, ref
end

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

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

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

]=]

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

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

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

]]

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

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

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

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

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

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

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

]]

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

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

Adds page to Category:CS1 maint: extra text if |page= or |pages= has what appears to be some form of p. or pp.
abbreviation in the first characters of the parameter content.

check Page and Pages for extraneous p, p., pp, and pp. at start of parameter value:
    good pattern: '^P[^%.P%l]' matches when |page(s)= begins PX or P# but not Px where x and X are letters and # is a dgiit
    bad pattern: '^[Pp][Pp]' matches matches when |page(s)= begins pp or pP or Pp or PP

]]

local function extra_text_in_page_check (page)
--    local good_pattern = '^P[^%.P%l]';
    local good_pattern = '^P[^%.Pp]';                                            -- ok to begin with uppercase P: P7 (pg 7 of section P) but not p123 (page 123) TODO: add Gg for PG or Pg?
--    local bad_pattern = '^[Pp][Pp]';
    local bad_pattern = '^[Pp]?[Pp]%.?[ %d]';

    if not page:match (good_pattern) and (page:match (bad_pattern) or  page:match ('^[Pp]ages?')) then
        add_maint_cat ('extra_text');
    end
--        if Page:match ('^[Pp]?[Pp]%.?[ %d]') or  Page:match ('^[Pp]ages?[ %d]') or
--            Pages:match ('^[Pp]?[Pp]%.?[ %d]') or  Pages:match ('^[Pp]ages?[ %d]') then
--                add_maint_cat ('extra_text');
--        end
end

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

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

    |vauthors=Jones AB, White EB, ((Black, Brown, and Co.))

This code is experimental and may not be retained.

]]
local function get_v_name_table (vparam, output_table)
    local name_table = mw.text.split(vparam, "%s*,%s*");                        -- names are separated by commas
    
    local i = 1;
    
    while name_table[i] do
        if name_table[i]:match ('^%(%(.*[^%)][^%)]$') then                        -- first segment of corporate with one or more commas; this segment has the opening doubled parens
            local name = name_table[i];
            i=i+1;                                                                -- bump indexer to next segment
            while name_table[i] do
                name = name .. ', ' .. name_table[i];                            -- concatenate with previous segments
                if name_table[i]:match ('^.*%)%)$') then                        -- if this table member has the closing doubled parens
                    break;                                                        -- and done reassembling so
                end
                i=i+1;                                                            -- bump indexer
            end
            table.insert (output_table, name);                                    -- and add corporate name to the output table
        else
            table.insert (output_table, name_table[i]);                            -- add this name
        end
        i = i+1;
    end    
    return output_table;
end

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

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

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

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

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

]]

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

    vparam, etal = name_has_etal (vparam, etal, true);                            -- find and remove variations on et al. do not categorize (do it here because et al. might have a period)
    if vparam:find ('%[%[') or vparam:find ('%]%]')    then                        -- no wikilinking vauthors names
        add_vanc_error ('wikilink');
    end
    v_name_table = get_v_name_table (vparam, v_name_table);                        -- names are separated by commas

    for i, v_name in ipairs(v_name_table) do
        if v_name:match ('^%(%(.+%)%)$') then                                    -- corporate authors are wrapped in doubled parentheses to supress vanc formatting and error detection
            first = '';                                                            -- set to empty string for concatenation and because it may have been set for previous author/editor
            last = v_name:match ('^%(%((.+)%)%)$')                                -- remove doubled parntheses
            corporate = true;                                                    -- flag used in list_people()
        elseif string.find(v_name, "%s") then
            if v_name:find('[;%.]') then                                        -- look for commonly occurring punctuation characters;
                add_vanc_error ('punctuation');
            end
            local lastfirstTable = {}
            lastfirstTable = mw.text.split(v_name, "%s")
            first = table.remove(lastfirstTable);                                -- removes and returns value of last element in table which should be author intials
            if is_suffix (first) then                                            -- if a valid suffix
                suffix = first                                                    -- save it as a suffix and
                first = table.remove(lastfirstTable);                            -- get what should be the initials from the table
            end                                                                    -- no suffix error message here because letter combination may be result of Romanization; check for digits?
            last = table.concat(lastfirstTable, " ")                            -- returns a string that is the concatenation of all other names that are not initials
            if mw.ustring.match (last, '%a+%s+%u+%s+%a+') then
                add_vanc_error ('missing comma');                                -- matches last II last; the case when a comma is missing
            end
            if mw.ustring.match (v_name, ' %u %u$') then                        -- this test is in the wrong place TODO: move or replace with a more appropriate test
                add_vanc_error ('name');                                        -- matches a space between two intiials
            end
        else
            first = '';                                                            -- set to empty string for concatenation and because it may have been set for previous author/editor
            last = v_name;                                                        -- last name or single corporate name?  Doesn't support multiword corporate names? do we need this?
        end
                                                                
        if is_set (first) then
            if not mw.ustring.match (first, "^%u?%u$") then                        -- first shall contain one or two upper-case letters, nothing else
                add_vanc_error ('initials');                                    -- too many initials; mixed case initials (which may be ok Romanization); hyphenated initials
            end
            is_good_vanc_name (last, first);                                    -- check first and last before restoring the suffix which may have a non-Latin digit
            if is_set (suffix) then
                first = first .. ' ' .. suffix;                                    -- if there was a suffix concatenate with the initials
                suffix = '';                                                    -- unset so we don't add this suffix to all subsequent names
            end
        else
            if not corporate then
                is_good_vanc_name (last, '');
            end
        end
                                                                                -- this from extract_names ()
        link = select_one( args, cfg.aliases[list_name .. '-Link'], 'redundant_parameters', i );
        mask = select_one( args, cfg.aliases[list_name .. '-Mask'], 'redundant_parameters', i );
        names[i] = {last = last, first = first, link = link, mask = mask, corporate=corporate};        -- add this assembled name to our names list
    end
    return names, etal;                                                            -- all done, return our list of names
end


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

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

Only one of these appropriate three will be used.  The hierarchy is: |authorn= (and aliases) highest and |authors= lowest and
similarly, |editorn= (and aliases) highest and |editors= lowest

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

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

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

]]

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

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

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


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

This function is used to validate a parameter's assigned value for those parameters that have only a limited number
of allowable values (yes, y, true, no, etc).  When the parameter value has not been assigned a value (missing or empty
in the source template) the function refurns true.  If the parameter value is one of the list of allowed values returns
true; else, emits an error message and returns false.

]]

local function is_valid_parameter_value (value, name, possible, cite_class)
-- begin hack to limit |mode=mla to a specific set of templates
    if ('mode' == name) and ('mla' == value) and not in_array (cite_class, {'book', 'journal', 'news'}) then
        table.insert( z.message_tail, { set_error( 'invalid_param_val', {name, value}, true ) } );    -- not an allowed value so add error message
        return false
    end
-- end hack

    if not is_set (value) then
        return true;                                                            -- an empty parameter is ok
    elseif in_array(value:lower(), possible) then
        return true;
    else
        table.insert( z.message_tail, { set_error( 'invalid_param_val', {name, value}, true ) } );    -- not an allowed value so add error message
        return false
    end
end


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

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

]]

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


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

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

]]
    
local function format_volume_issue (volume, issue, cite_class, origin, sepc, lower, mode)
    if not is_set (volume) and not is_set (issue) then
        return '';
    end
    
    if ('mla' == mode) and ('journal' == cite_class) then                        -- same as cs1 for magazines
        lower = true;                                                            -- mla 8th edition; force these to lower case
        if is_set (volume) and is_set (issue) then
            return wrap_msg ('vol-no', {sepc, volume, issue}, lower);
        elseif is_set (volume) then
            return wrap_msg ('vol', {sepc, volume}, lower);
        else
            return '';
        end
    end

    if 'magazine' == cite_class or (in_array (cite_class, {'citation', 'map'}) and 'magazine' == origin) then
        if is_set (volume) and is_set (issue) then
            return wrap_msg ('vol-no', {sepc, volume, issue}, lower);
        elseif is_set (volume) then
            return wrap_msg ('vol', {sepc, volume}, lower);
        else
            return wrap_msg ('issue', {sepc, issue}, lower);
        end
    end

    local vol = '';
        
    if is_set (volume) then
        if (4 < mw.ustring.len(volume)) then
            vol = substitute (cfg.messages['j-vol'], {sepc, volume});
        else
            vol = substitute (cfg.presentation['vol-bold'], {sepc, hyphen_to_dash(volume)});
        end
    end
    if is_set (issue) then
        return vol .. substitute (cfg.messages['j-issue'], issue);
    end
    return vol;
end


--[[-------------------------< N O R M A L I Z E _ P A G E _ L I S T >-----------------------------------------

not currently used

normalizes a comma, ampersand, and/or space separated list to be '<value>, <value>, ..., <value>'
returns list unchanged if there are no commas else strips whitespace and then reformats the list

]]
--[[
local function normalize_page_list (list)
    if not list:find ('[,& ]') then return list end                                -- if list is not delimited with commas, ampersands, or spaces; done
    
    list = mw.text.split (list, '[,&%s]+');                                        -- make a table of values
    list = table.concat (list, ', ');                                            -- and now make a normalized list
    return list;
end
]]


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

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

Singular has priority over plural when both are provided.

]]

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

    local is_journal = 'journal' == cite_class or (in_array (cite_class, {'citation', 'map'}) and 'journal' == origin);
    
    if is_journal and 'mla' == mode then
        is_journal = false;                                                        -- mla always uses p & pp
    end

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


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

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

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

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

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

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

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

]=]

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

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


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

Look at the contents of a parameter. If the content has a string of characters and digits followed by an equal
sign, compare the alphanumeric string to the list of cs1|2 parameters.  If found, then the string is possibly a
parameter that is missing its pipe:
    {{cite ... |title=Title access-date=2016-03-17}}

cs1|2 shares some parameter names with xml/html atributes: class=, title=, etc.  To prevent false positives xml/html
tags are removed before the search.

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

]]

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

    capture = value:match ('%s+(%a[%a%d]+)%s*=') or value:match ('^(%a[%a%d]+)%s*=');    -- find and categorize parameters with possible missing pipes
    if capture and validate (capture) then                                -- if the capture is a valid parameter name
        add_maint_cat ('missing_pipe');
    end
end


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

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

]]

local function citation0( config, args)
    --[[
    Load Input Parameters
    The argument_wrapper facilitates the mapping of multiple aliases to single internal variable.
    ]]
    local A = argument_wrapper( args );
    local i

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

-- set default parameter values defined by |mode= parameter.  If |mode= is empty or omitted, use CitationClass to set these values
    local Mode = A['Mode'];
    if not is_valid_parameter_value (Mode, 'mode', cfg.keywords['mode'], config.CitationClass) then
        Mode = '';
    end

    local author_etal;
    local a    = {};                                                                -- authors list from |lastn= / |firstn= pairs or |vauthors=
    local Authors;
    local NameListFormat = A['NameListFormat'];
    local Collaboration = A['Collaboration'];

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

    local Others = A['Others'];

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

    do                                                                            -- to limit scope of selected
        local selected = select_author_editor_source (A['Veditors'], A['Editors'], args, 'EditorList');
        if 1 == selected then
            e, editor_etal = extract_names (args, 'EditorList');                -- fetch editor list from |editorn= / |editor-lastn= / |editor-firstn=, |editor-linkn=, and |editor-maskn=
        elseif 2 == selected then
            NameListFormat = 'vanc';                                            -- override whatever |name-list-format= might be
            e, editor_etal = parse_vauthors_veditors (args, args.veditors, 'EditorList');    -- fetch editor list from |veditors=, |editor-linkn=, and |editor-maskn=
        elseif 3 == selected then
            Editors = A['Editors'];                                                -- use content of |editors=
            add_maint_cat ('editors');                                            -- but add a maint cat because use of this parameter is discouraged
        end
    end

    local t = {};                                                                -- translators list from |translator-lastn= / translator-firstn= pairs
    local Translators;                                                            -- assembled translators name list
    t = extract_names (args, 'TranslatorList');                                    -- fetch translator list from |translatorn= / |translator-lastn=, -firstn=, -linkn=, -maskn=
    

    local interviewers_list = {};
    local Interviewers = A['Interviewers']
    if is_set (Interviewers) then                                                -- add a maint cat if the |interviewers= is used
        add_maint_cat ('interviewers');                                            -- because use of this parameter is discouraged
    else
        interviewers_list = extract_names (args, 'InterviewerList');            -- else, process preferred interviewers parameters
    end

    local c = {};                                                                -- contributors list from |contributor-lastn= / contributor-firstn= pairs
    local Contributors;                                                            -- assembled contributors name list
    local Contribution = A['Contribution'];
    if in_array(config.CitationClass, {"book","citation"}) and not is_set(A['Periodical']) then    -- |contributor= and |contribution= only supported in book cites
        c = extract_names (args, 'ContributorList');                            -- fetch contributor list from |contributorn= / |contributor-lastn=, -firstn=, -linkn=, -maskn=
        
        if 0 < #c then
            if not is_set (Contribution) then                                    -- |contributor= requires |contribution=
                table.insert( z.message_tail, { set_error( 'contributor_missing_required_param', 'contribution')});    -- add missing contribution error message
                c = {};                                                            -- blank the contributors' table; it is used as a flag later
            end
            if 0 == #a then                                                        -- |contributor= requires |author=
                table.insert( z.message_tail, { set_error( 'contributor_missing_required_param', 'author')});    -- add missing author error message
                c = {};                                                            -- blank the contributors' table; it is used as a flag later
            end
        end
    else                                                                        -- if not a book cite
        if select_one (args, cfg.aliases['ContributorList-Last'], 'redundant_parameters', 1 ) then    -- are there contributor name list parameters?
            table.insert( z.message_tail, { set_error( 'contributor_ignored')});    -- add contributor ignored error message
        end
        Contribution = nil;                                                        -- unset
    end

    if not is_valid_parameter_value (NameListFormat, 'name-list-format', cfg.keywords['name-list-format']) then            -- only accepted value for this parameter is 'vanc'
        NameListFormat = '';                                                    -- anything else, set to empty string
    end

    local Year = A['Year'];
    local PublicationDate = A['PublicationDate'];
    local OrigYear = A['OrigYear'];
    local Date = A['Date'];
    local LayDate = A['LayDate'];
    ------------------------------------------------- Get title data
    local Title = A['Title'];
    local ScriptTitle = A['ScriptTitle'];
    local BookTitle = A['BookTitle'];
    local Conference = A['Conference'];
    local TransTitle = A['TransTitle'];
    local TitleNote = A['TitleNote'];
    local TitleLink = A['TitleLink'];
            link_title_ok (TitleLink, A:ORIGIN ('TitleLink'), Title, 'title');    -- check for wikimarkup in |title-link= or wikimarkup in |title= when |title-link= is set

    local Chapter = A['Chapter'];
    local ScriptChapter = A['ScriptChapter'];
    local ChapterLink    -- = A['ChapterLink'];                                    -- deprecated as a parameter but still used internally by cite episode
    local TransChapter = A['TransChapter'];
    local TitleType = A['TitleType'];
    local Degree = A['Degree'];
    local Docket = A['Docket'];
    local ArchiveFormat = A['ArchiveFormat'];

    local ArchiveDate;
    local ArchiveURL;

    ArchiveURL, ArchiveDate = archive_url_check (A['ArchiveURL'], A['ArchiveDate'])
    
    local DeadURL = A['DeadURL']
        if not is_valid_parameter_value (DeadURL, 'dead-url', cfg.keywords ['deadurl']) then    -- set in config.defaults to 'yes'
            DeadURL = '';                                                        -- anything else, set to empty string
        end

    local URL = A['URL']
    local URLorigin = A:ORIGIN('URL');                                            -- get name of parameter that holds URL
    local ChapterURL = A['ChapterURL'];
    local ChapterURLorigin = A:ORIGIN('ChapterURL');                            -- get name of parameter that holds ChapterURL
    local ConferenceFormat = A['ConferenceFormat'];
    local ConferenceURL = A['ConferenceURL'];
    local ConferenceURLorigin = A:ORIGIN('ConferenceURL');                        -- get name of parameter that holds ConferenceURL
    local Periodical = A['Periodical'];
    local Periodical_origin = A:ORIGIN('Periodical');                            -- get the name of the periodical parameter

    local Series = A['Series'];
    
    local Volume;
    local Issue;
    local Page;
    local Pages;
    local At;
                                                                                -- previously conference books did not support volume
--    if in_array (config.CitationClass, cfg.templates_using_volume) and not ('conference' == config.CitationClass and not is_set (Periodical)) then
    if in_array (config.CitationClass, cfg.templates_using_volume) then
        Volume = A['Volume'];
    end
                                                                                -- conference & map books do not support issue
    if in_array (config.CitationClass, cfg.templates_using_issue) and not (in_array (config.CitationClass, {'conference', 'map'}) and not is_set (Periodical))then
        Issue = A['Issue'];
    end
    local Position = '';
    if not in_array (config.CitationClass, cfg.templates_not_using_page) then
        Page = A['Page'];
        Pages = hyphen_to_dash( A['Pages'] );    
        At = A['At'];
    end

    local Edition = A['Edition'];
    local PublicationPlace = A['PublicationPlace']
    local Place = A['Place'];
    
    local PublisherName = A['PublisherName'];
    local RegistrationRequired = A['RegistrationRequired'];
        if not is_valid_parameter_value (RegistrationRequired, 'registration', cfg.keywords ['yes_true_y']) then
            RegistrationRequired=nil;
        end
    local SubscriptionRequired = A['SubscriptionRequired'];
        if not is_valid_parameter_value (SubscriptionRequired, 'subscription', cfg.keywords ['yes_true_y']) then
            SubscriptionRequired=nil;
        end
    local UrlAccess = A['UrlAccess'];
        if not is_valid_parameter_value (UrlAccess, 'url-access', cfg.keywords ['url-access']) then
            UrlAccess = nil;
        end
        if not is_set(URL) and is_set(UrlAccess) then
            UrlAccess = nil;
            table.insert( z.message_tail, { set_error( 'param_access_requires_param', {'url'}, true ) } );
        end

        if is_set (UrlAccess) and is_set (SubscriptionRequired) then            -- while not aliases, these are much the same so if both are set
            table.insert( z.message_tail, { set_error( 'redundant_parameters', {wrap_style ('parameter', 'url-access') .. ' and ' .. wrap_style ('parameter', 'subscription')}, true ) } );        -- add error message
            SubscriptionRequired = nil;                                            -- unset; prefer |access= over |subscription=
        end
        if is_set (UrlAccess) and is_set (RegistrationRequired) then            -- these are not the same but contradictory so if both are set
            table.insert( z.message_tail, { set_error( 'redundant_parameters', {wrap_style ('parameter', 'url-access') .. ' and ' .. wrap_style ('parameter', 'registration')}, true ) } );        -- add error message
            RegistrationRequired = nil;                                            -- unset; prefer |access= over |registration=
        end


    local Via = A['Via'];
    local AccessDate = A['AccessDate'];
    local Agency = A['Agency'];

    local Language = A['Language'];
    local Format = A['Format'];
    local ChapterFormat = A['ChapterFormat'];
    local DoiBroken = A['DoiBroken'];
    local ID = A['ID'];
    local ASINTLD = A['ASINTLD'];
    local IgnoreISBN = A['IgnoreISBN'];
        if not is_valid_parameter_value (IgnoreISBN, 'ignore-isbn-error', cfg.keywords ['yes_true_y']) then
            IgnoreISBN = nil;                                                    -- anything else, set to empty string
        end
    local Embargo = A['Embargo'];
    local Class = A['Class'];                                                    -- arxiv class identifier

    local ID_list = extract_ids( args );
    local ID_access_levels = extract_id_access_levels( args, ID_list );

    local Quote = A['Quote'];

    local LayFormat = A['LayFormat'];
    local LayURL = A['LayURL'];
    local LaySource = A['LaySource'];
    local Transcript = A['Transcript'];
    local TranscriptFormat = A['TranscriptFormat'];
    local TranscriptURL = A['TranscriptURL']
    local TranscriptURLorigin = A:ORIGIN('TranscriptURL');                        -- get name of parameter that holds TranscriptURL

    local LastAuthorAmp = A['LastAuthorAmp'];
        if not is_valid_parameter_value (LastAuthorAmp, 'last-author-amp', cfg.keywords ['yes_true_y']) then
            LastAuthorAmp = nil;                                                -- set to empty string
        end
        if 'mla' == Mode then                                                
            LastAuthorAmp = 'yes';                                                -- replaces last author/editor separator with ' and ' text
        end
    local no_tracking_cats = A['NoTracking'];
        if not is_valid_parameter_value (no_tracking_cats, 'no-tracking', cfg.keywords ['yes_true_y']) then
            no_tracking_cats = nil;                                                -- set to empty string
        end

--local variables that are not cs1 parameters
    local use_lowercase;                                                        -- controls capitalization of certain static text
    local this_page = mw.title.getCurrentTitle();                                -- also used for COinS and for language
    local anchor_year;                                                            -- used in the CITEREF identifier
    local COinS_date = {};                                                        -- holds date info extracted from |date= for the COinS metadata by Module:Date verification

    local DF = A['DF'];                                                            -- date format set in cs1|2 template
    if not is_valid_parameter_value (DF, 'df', cfg.keywords['date-format']) then    -- validate reformatting keyword
        DF = '';                                                                -- not valid, set to empty string
    end

    local sepc;                                            -- separator between citation elements for CS1 a period, for CS2, a comma
    local PostScript;
    local Ref;
    sepc, PostScript, Ref = set_style (Mode:lower(), A['PostScript'], A['Ref'], config.CitationClass);
    use_lowercase = ( sepc == ',' );                    -- used to control capitalization for certain static text

--check this page to see if it is in one of the namespaces that cs1 is not supposed to add to the error categories
    if not is_set (no_tracking_cats) then                                        -- ignore if we are already not going to categorize this page
        if in_array (this_page.nsText, cfg.uncategorized_namespaces) then
            no_tracking_cats = "true";                                            -- set no_tracking_cats
        end
        for _,v in ipairs (cfg.uncategorized_subpages) do                        -- cycle through page name patterns
            if this_page.text:match (v) then                                    -- test page name against each pattern
                no_tracking_cats = "true";                                        -- set no_tracking_cats
                break;                                                            -- bail out if one is found
            end
        end
    end

-- check for extra |page=, |pages= or |at= parameters. (also sheet and sheets while we're at it)
    select_one( args, {'page', 'p', 'pp', 'pages', 'at', 'sheet', 'sheets'}, 'redundant_parameters' );        -- this is a dummy call simply to get the error message and category

    local NoPP = A['NoPP']
    if is_set (NoPP) and is_valid_parameter_value (NoPP, 'nopp', cfg.keywords ['yes_true_y']) then
        NoPP = true;
    else
        NoPP = nil;                                                                -- unset, used as a flag later
    end

    if is_set(Page) then
        if is_set(Pages) or is_set(At) then
            Pages = '';                                                            -- unset the others
            At = '';
        end
        extra_text_in_page_check (Page);                                        -- add this page to maint cat if |page= value begins with what looks like p. or pp.
    elseif is_set(Pages) then
        if is_set(At) then
            At = '';                                                            -- unset
        end
        extra_text_in_page_check (Pages);                                        -- add this page to maint cat if |pages= value begins with what looks like p. or pp.
    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
    |url maps to |chapterurl when |title is remapped

All other combinations of |encyclopedia, |title, and |article are not modified

]]

local Encyclopedia = A['Encyclopedia'];

    if ( config.CitationClass == "encyclopaedia" ) or ( config.CitationClass == "citation" and is_set (Encyclopedia)) then    -- test code for citation
        if is_set(Periodical) then                                                -- Periodical is set when |encyclopedia is set
            if is_set(Title) or is_set (ScriptTitle) then
                if not is_set(Chapter) then
                    Chapter = Title;                                            -- |encyclopedia and |title are set so map |title to |article and |encyclopedia to |title
                    ScriptChapter = ScriptTitle;
                    TransChapter = TransTitle;
                    ChapterURL = URL;
                    if not is_set (ChapterURL) and is_set (TitleLink) then
                        Chapter= '[[' .. TitleLink .. '|' .. Chapter .. ']]';
                    end
                    Title = Periodical;
                    ChapterFormat = Format;
                    Periodical = '';                                            -- redundant so unset
                    TransTitle = '';
                    URL = '';
                    Format = '';
                    TitleLink = '';
                    ScriptTitle = '';
                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 case for cite techreport.
    if (config.CitationClass == "techreport") then                                -- special case for cite techreport
        if is_set(A['Number']) then                                                -- cite techreport uses 'number', which other citations alias to 'issue'
            if not is_set(ID) then                                                -- can we use ID for the "number"?
                ID = A['Number'];                                                -- yes, use it
            else                                                                -- ID has a value so emit error message
                table.insert( z.message_tail, { set_error('redundant_parameters', {wrap_style ('parameter', 'id') .. ' and ' .. wrap_style ('parameter', 'number')}, true )});
            end
        end    
    end

-- special case for cite mailing list
    if (config.CitationClass == "mailinglist") then
        Periodical = A ['MailingList'];
    elseif 'mailinglist' == A:ORIGIN('Periodical') then
        Periodical = '';                                                        -- unset because mailing list is only used for cite mailing list
    end

-- Account for the oddity that is {{cite conference}}, before generation of COinS data.
    if 'conference' == config.CitationClass then
        if is_set(BookTitle) then
            Chapter = Title;
--            ChapterLink = TitleLink;                                            -- |chapterlink= is deprecated
            ChapterURL = URL;
            ChapterURLorigin = URLorigin;
            URLorigin = '';
            ChapterFormat = Format;
            TransChapter = TransTitle;
            Title = BookTitle;
            Format = '';
--            TitleLink = '';
            TransTitle = '';
            URL = '';
        end
    elseif 'speech' ~= config.CitationClass then
        Conference = '';                                                        -- not cite conference or cite speech so make sure this is empty string
    end

-- cite map oddities
    local Cartography = "";
    local Scale = "";
    local Sheet = A['Sheet'] or '';
    local Sheets = A['Sheets'] or '';
    if config.CitationClass == "map" then
        Chapter = A['Map'];
        ChapterURL = A['MapURL'];
        TransChapter = A['TransMap'];
        ChapterURLorigin = A:ORIGIN('MapURL');
        ChapterFormat = A['MapFormat'];
        
        Cartography = A['Cartography'];
        if is_set( Cartography ) then
            Cartography = sepc .. " " .. wrap_msg ('cartography', Cartography, use_lowercase);
        end        
        Scale = A['Scale'];
        if is_set( Scale ) then
            Scale = sepc .. " " .. Scale;
        end
    end

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

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

        local Network = A['Network'];
        local Station = A['Station'];
        local s, n = {}, {};
                                                                                -- do common parameters first
        if is_set(Network) then table.insert(n, Network); end
        if is_set(Station) then table.insert(n, Station); end
        ID = table.concat(n, sepc .. ' ');
        
        if not is_set (Date) and is_set (AirDate) then                            -- promote airdate to date
            Date = AirDate;
        end

        if 'episode' == config.CitationClass then                                -- handle the oddities that are strictly {{cite episode}}
            local Season = A['Season'];
            local SeriesNumber = A['SeriesNumber'];

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

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

-- Account for the oddities that are {{cite arxiv}}, {{cite biorxiv}}, {{cite citeseerx}}, before generation of COinS data.
    do
        if in_array (config.CitationClass, {'arxiv', 'biorxiv', 'citeseerx'}) then
            if not is_set (ID_list[config.CitationClass:upper()]) then            -- |arxiv= or |eprint= required for cite arxiv; |biorxiv= & |citeseerx= required for their templates
                table.insert( z.message_tail, { set_error( config.CitationClass .. '_missing', {}, true ) } );        -- add error message
            end
            
            if 'arxiv' == config.CitationClass then
                Periodical = 'arXiv';                                            -- set to arXiv for COinS; after that, must be set to empty string
            end
            if 'biorxiv' == config.CitationClass then
                Periodical = 'bioRxiv';                                            -- set to bioRxiv for COinS; after that, must be set to empty string
            end
            if 'citeseerx' == config.CitationClass then
                Periodical = 'CiteSeerX';                                        -- set to CiteSeerX for COinS; after that, must be set to empty string
            end
        end
    end

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

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

-- legacy: promote PublicationDate to Date if neither Date nor Year are set.
    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 not is_set (Date) and is_set(PublicationDate) then                    -- use PublicationDate when |date= and |year= are not set
            Date = PublicationDate;                                                -- promote PublicationDate to Date
            PublicationDate = '';                                                -- unset, no longer needed
        end
    end

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

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

Date validation supporting code is in Module:Citation/CS1/Date_validation
]]
    do    -- create defined block to contain local variables error_message, date_parameters_list, mismatch
        local error_message = '';
                                                                                -- AirDate has been promoted to Date so not necessary to check it
        local date_parameters_list = {['access-date']=AccessDate, ['archive-date']=ArchiveDate, ['date']=Date, ['doi-broken-date']=DoiBroken,
                ['embargo']=Embargo, ['lay-date']=LayDate, ['publication-date']=PublicationDate, ['year']=Year};

        anchor_year, Embargo, error_message = dates(date_parameters_list, COinS_date);

        if is_set (Year) and is_set (Date) then                                    -- both |date= and |year= not normally needed;
            local mismatch = year_date_check (Year, Date)
            if 0 == mismatch then                                                -- |year= does not match a year-value in |date=
                if is_set (error_message) then                                    -- if there is already an error message
                    error_message = error_message .. ', ';                        -- tack on this additional message
                end
                error_message = error_message .. '&#124;year= / &#124;date= mismatch';
            elseif 1 == mismatch then                                            -- |year= matches year-value in |date=
                add_maint_cat ('date_year');
            end
        end
        
        if not is_set(error_message) then                                        -- error free dates only
            local modified = false;                                                -- flag
            if is_set (DF) then                                                    -- if we need to reformat dates
                modified = reformat_dates (date_parameters_list, DF, false);    -- reformat to DF format, use long month names if appropriate
            end

            if true == date_hyphen_to_dash (date_parameters_list) then                    -- convert hyphens to dashes where appropriate
                modified = true;
                add_maint_cat ('date_format');                                    -- hyphens were converted so add maint category
            end
            
            if modified then                                                    -- if the date_parameters_list values were modified
                AccessDate = date_parameters_list['access-date'];                -- overwrite date holding parameters with modified values
                ArchiveDate = date_parameters_list['archive-date'];
                Date = date_parameters_list['date'];
                DoiBroken = date_parameters_list['doi-broken-date'];
                LayDate = date_parameters_list['lay-date'];
                PublicationDate = date_parameters_list['publication-date'];
            end
        else
            table.insert( z.message_tail, { set_error( 'bad_date', {error_message}, true ) } );    -- add this error message
        end
    end    -- end of do

-- Account for the oddity that is {{cite journal}} with |pmc= set and |url= not set.  Do this after date check but before COInS.
-- Here we unset Embargo if PMC not embargoed (|embargo= not set in the citation) or if the embargo time has expired. Otherwise, holds embargo date
    Embargo = is_embargoed (Embargo);                                            --

    if config.CitationClass == "journal" and not is_set(URL) and is_set(ID_list['PMC']) then
        if not is_set (Embargo) then                                            -- if not embargoed or embargo has expired
            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=
            if is_set(AccessDate) then                                            -- access date requires |url=; pmc created url is not |url=
                table.insert( z.message_tail, { set_error( 'accessdate_missing_url', {}, true ) } );
                AccessDate = '';                                                -- unset
            end

        end
    end

-- At this point fields may be nil if they weren't specified in the template use.  We can use that fact.
    -- Test if citation has no title
    if    not is_set(Title) and
        not is_set(TransTitle) and
        not is_set(ScriptTitle) then
            if 'episode' == config.CitationClass then                            -- special case for cite episode; TODO: is there a better way to do this?
                table.insert( z.message_tail, { set_error( 'citation_missing_title', {'series'}, true ) } );
            else
                table.insert( z.message_tail, { set_error( 'citation_missing_title', {'title'}, true ) } );
            end
    end
    
    if 'none' == Title and in_array (config.CitationClass, {'journal', 'citation'}) and is_set (Periodical) and 'journal' == A:ORIGIN('Periodical') then    -- special case for journal cites
        Title = '';                                                                -- set title to empty string
        add_maint_cat ('untitled');
    end

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

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

    -- this is the function call to COinS()
    local OCinSoutput = COinS({
        ['Periodical'] = Periodical,
        ['Encyclopedia'] = Encyclopedia,
        ['Chapter'] = make_coins_title (coins_chapter, ScriptChapter),            -- Chapter and ScriptChapter stripped of bold / italic wikimarkup
        ['Degree'] = Degree;                                                    -- cite thesis only
        ['Title'] = make_coins_title (coins_title, ScriptTitle),                -- Title and ScriptTitle stripped of bold / italic wikimarkup
        ['PublicationPlace'] = PublicationPlace,
        ['Date'] = COinS_date.rftdate,                                            -- COinS_date has correctly formatted date if Date is valid;
        ['Season'] = COinS_date.rftssn,
        ['Chron'] =  COinS_date.rftchron or (not COinS_date.rftdate and Date) or '',    -- chron but if not set and invalid date format use Date; keep this last bit?
        ['Series'] = Series,
        ['Volume'] = Volume,
        ['Issue'] = Issue,
        ['Pages'] = get_coins_pages (first_set ({Sheet, Sheets, Page, Pages, At}, 5)),                -- pages stripped of external links
        ['Edition'] = Edition,
        ['PublisherName'] = PublisherName,
        ['URL'] = first_set ({ChapterURL, URL}, 2),
        ['Authors'] = coins_author,
        ['ID_list'] = ID_list,
        ['RawPage'] = this_page.prefixedText,
    }, config.CitationClass);

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

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



    -- Now perform various field substitutions.
    -- We also add leading spaces and surrounding markup and punctuation to the
    -- various parts of the citation, but only when they are non-nil.
    local EditorCount;                                                            -- used only for choosing {ed.) or (eds.) annotation at end of editor name-list
    do
        local last_first_list;
        local control = {
            format = NameListFormat,                                            -- empty string or 'vanc'
            maximum = nil,                                                        -- as if display-authors or display-editors not set
            lastauthoramp = LastAuthorAmp,
            page_name = this_page.text,                                            -- get current page name so that we don't wikilink to it via editorlinkn
            mode = Mode
        };

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

            if is_set (Editors) then
                if editor_etal then
                    Editors = Editors .. ' ' .. cfg.messages['et al'];            -- add et al. to editors parameter beause |display-editors=etal
                    EditorCount = 2;                                            -- with et al., |editors= is multiple names; spoof to display (eds.) annotation
                else
                    EditorCount = 2;                                            -- we don't know but assume |editors= is multiple names; spoof to display (eds.) annotation
                end
            else
                Editors = last_first_list;                                        -- either an author name list or an empty string
            end

            if 1 == EditorCount and (true == editor_etal or 1 < #e) then        -- only one editor displayed but includes etal then
                EditorCount = 2;                                                -- spoof to display (eds.) annotation
            end
        end
        do                                                                        -- now do interviewers
            control.maximum = #interviewers_list;                            -- number of interviewerss
            Interviewers = list_people(control, interviewers_list, false);    -- et al not currently supported
        end
        do                                                                        -- now do translators
            control.maximum = #t;                                                -- number of translators
            Translators = list_people(control, t, false);                        -- et al not currently supported
        end
        do                                                                        -- now do contributors
            control.maximum = #c;                                                -- number of contributors
            Contributors = list_people(control, c, false);                        -- et al not currently supported
        end
        do                                                                        -- now do authors
            control.maximum , author_etal = get_display_authors_editors (A['DisplayAuthors'], #a, 'authors', author_etal);

            last_first_list = list_people(control, a, author_etal);

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

    end

-- apply |[xx-]format= styling; at the end, these parameters hold correctly styled format annotation,
-- an error message if the associated url is not set, or an empty string for concatenation
    ArchiveFormat = style_format (ArchiveFormat, ArchiveURL, 'archive-format', 'archive-url');
    ConferenceFormat = style_format (ConferenceFormat, ConferenceURL, 'conference-format', 'conference-url');
    Format = style_format (Format, URL, 'format', 'url');
    LayFormat = style_format (LayFormat, LayURL, 'lay-format', 'lay-url');
    TranscriptFormat = style_format (TranscriptFormat, TranscriptURL, 'transcript-format', 'transcripturl');

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

    if not is_set(URL) then
        if in_array(config.CitationClass, {"web","podcast", "mailinglist"}) then    -- |url= required for cite web, cite podcast, and cite mailinglist
            table.insert( z.message_tail, { set_error( 'cite_web_url', {}, true ) } );
        end
        
        -- do we have |accessdate= without either |url= or |chapter-url=?
        if is_set(AccessDate) and not is_set(ChapterURL)then                    -- ChapterURL may be set when URL is not set;
            table.insert( z.message_tail, { set_error( 'accessdate_missing_url', {}, true ) } );
            AccessDate = '';
        end
    end

    local OriginalURL, OriginalURLorigin, OriginalFormat, OriginalAccess;
    DeadURL = DeadURL:lower();                                                    -- used later when assembling archived text
    if is_set( ArchiveURL ) then
        if is_set (ChapterURL) then                                             -- URL not set so if chapter-url is set apply archive url to it
            OriginalURL = ChapterURL;                                            -- save copy of source chapter's url for archive text
            OriginalURLorigin = ChapterURLorigin;                                -- name of chapter-url parameter for error messages
            OriginalFormat = ChapterFormat;                                        -- and original |format=
            if 'no' ~= DeadURL then
                ChapterURL = ArchiveURL                                            -- swap-in the archive's url
                ChapterURLorigin = A:ORIGIN('ArchiveURL')                        -- name of archive-url parameter for error messages
                ChapterFormat = ArchiveFormat or '';                            -- swap in archive's format
            end
        elseif is_set (URL) then
            OriginalURL = URL;                                                    -- save copy of original source URL
            OriginalURLorigin = URLorigin;                                        -- name of url parameter for error messages
            OriginalFormat = Format;                                             -- and original |format=
            OriginalAccess = UrlAccess;
            if 'no' ~= DeadURL then                                                -- if URL set then archive-url applies to it
                URL = ArchiveURL                                                -- swap-in the archive's url
                URLorigin = A:ORIGIN('ArchiveURL')                                -- name of archive url parameter for error messages
                Format = ArchiveFormat or '';                                    -- swap in archive's format
                UrlAccess = nil;                                                -- restricted access levels do not make sense for archived urls
            end
         end
    end

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

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

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

    -- Format main title.
    if is_set(TitleLink) and is_set(Title) then
        Title = "[[" .. TitleLink .. "|" .. Title .. "]]"
    end

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

    local TransError = "";
    if is_set(TransTitle) then
        if is_set(Title) then
            TransTitle = " " .. TransTitle;
        else
            TransError = " " .. set_error( 'trans_missing_title', {'title'} );
        end
    end
    
    if is_set(Title) then
        if not is_set(TitleLink) and is_set(URL) then
            
            Title = external_link( URL, Title, URLorigin, UrlAccess ) .. TransTitle .. TransError .. Format;
-- this experiment hidden 2016-04-10; see Help_talk:Citation_Style_1#Recycled_urls
--            local temp_title = external_link( URL, Title, URLorigin ) .. TransError .. Format;    -- do this so we get error message even if url is usurped no archive
--            if in_array (DeadURL, {'unfit no archive', 'usurped no archive'}) then    -- when url links to inappropriate location and there is no archive of original source available
--                local err_msg
--                if temp_title:match ('%[%S+%s+(.+)%](<.+)') then                -- if there is an error message
--                    Title, err_msg = temp_title:match ('%[%S+%s+(.+)%](<.+)');    -- strip off external link; TODO: find a better to do this
--                    Title = Title .. (err_msg or '');
--                end
--            else
--                Title = temp_title;
--            end

            URL = '';                                                            -- unset these because no longer needed
            Format = "";
        else
            Title = Title .. TransTitle .. TransError;
        end
    end

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

    if is_set (Conference) then
        if is_set (ConferenceURL) then
            Conference = external_link( ConferenceURL, Conference, ConferenceURLorigin, nil );
        end
        Conference = sepc .. " " .. Conference .. ConferenceFormat;
    elseif is_set(ConferenceURL) then
        Conference = sepc .. " " .. external_link( ConferenceURL, nil, ConferenceURLorigin, nil );
    end

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

        if is_set(Minutes) then
            if is_set (Time) then
                table.insert( z.message_tail, { set_error( 'redundant_parameters', {wrap_style ('parameter', 'minutes') .. ' and ' .. wrap_style ('parameter', 'time')}, true ) } );
            end
            Position = " " .. Minutes .. " " .. cfg.messages['minutes'];
        else
            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

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

    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 Sections = A['Sections'];
        local Inset = A['Inset'];
        
        if is_set( Inset ) then
            Inset = sepc .. " " .. wrap_msg ('inset', Inset, use_lowercase);
        end            

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

    if is_set (Language) then
        Language = language_parameter (Language);                                -- format, categories, name from ISO639-1, etc
    else
        Language="";                                                            -- language not specified so make sure this is an empty string;
    --[[ TODO: need to extract the wrap_msg from language_parameter
    so that we can solve parentheses bunching problem with Format/Language/TitleType
    ]]
    end

    Others = is_set(Others) and (sepc .. " " .. Others) or "";
    
    if is_set (Translators) then
        if 'mla' == Mode then
            Others = sepc .. ' Trans. ' .. Translators .. Others;
        else
            Others = sepc .. ' ' .. wrap_msg ('translated', Translators, use_lowercase) .. Others;
        end
    end
    if is_set (Interviewers) then
        Others = sepc .. ' ' .. wrap_msg ('interview', Interviewers, use_lowercase) .. Others;
    end
    
    TitleNote = is_set(TitleNote) and (sepc .. " " .. TitleNote) or "";
    if is_set (Edition) then
        if Edition:match ('%f[%a][Ee]d%.?$') or Edition:match ('%f[%a][Ee]dition$') then
            add_maint_cat ('extra_text', 'edition');
        end
        if 'mla' == Mode then
            Edition = '. ' .. Edition .. ' ed.';
        else
            Edition = " " .. wrap_msg ('edition', Edition);
        end
    else
        Edition = '';
    end

    Series = is_set(Series) and (sepc .. " " .. Series) or "";
    if 'mla' == Mode then                                                        -- not in brackets for mla
        OrigYear = is_set(OrigYear) and (". " .. OrigYear) or "";
    else
        OrigYear = is_set(OrigYear) and (" [" .. OrigYear .. "]") or "";
    end
    Agency = is_set(Agency) and (sepc .. " " .. Agency) or "";

    Volume = format_volume_issue (Volume, Issue, config.CitationClass, Periodical_origin, sepc, use_lowercase, Mode);

    ------------------------------------ totally unrelated data
    if is_set(Via) then
        Via = " " .. wrap_msg ('via', Via);
    end

--[[
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 (SubscriptionRequired) then
        SubscriptionRequired = sepc .. " " .. cfg.messages['subscription'];        -- subscription required message
    elseif is_set (RegistrationRequired) then
        SubscriptionRequired = sepc .. " " .. cfg.messages['registration'];        -- registration required message
    else
        SubscriptionRequired = '';                                                -- either or both might be set to something other than yes true y
    end

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

        AccessDate = nowrap_date (AccessDate);                                    -- wrap in nowrap span if date in appropriate format
        if 'mla' == Mode then                                                    -- retrieved text not used in mla
            AccessDate = ' ' .. AccessDate;
        else
            if (sepc ~= ".") then retrv_text = retrv_text:lower() end            -- if mode is cs2, lower case
            AccessDate = substitute (retrv_text, AccessDate);                    -- add retrieved text
        end
        AccessDate = substitute (cfg.presentation['accessdate'], {sepc, AccessDate});    -- allow editors to hide accessdates
    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
       if "report" == config.CitationClass and is_set(Docket) then                    -- for cite report when |docket= is set
        ID = sepc .. ' ' .. Docket;                                                -- overwrite ID even if |id= is set
    end

    ID_list = build_id_list( ID_list, {IdAccessLevels=ID_access_levels, DoiBroken = DoiBroken, ASINTLD = ASINTLD, IgnoreISBN = IgnoreISBN, Embargo=Embargo, Class = Class} );

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

    if is_set(Quote) then
        if Quote:sub(1,1) == '"' and Quote:sub(-1,-1) == '"' then                -- if first and last characters of quote are quote marks
            Quote = Quote:sub(2,-2);                                            -- strip them off
        end
        Quote = sepc .." " .. wrap_style ('quoted-text', Quote );                 -- wrap in <q>...</q> tags
        PostScript = "";                                                        -- cs1|2 does not supply terminal punctuation when |quote= is set
    end
    
    local Archived
    if is_set(ArchiveURL) then
        if not is_set(ArchiveDate) then
            ArchiveDate = set_error('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'],
                { external_link( ArchiveURL, arch_text, A:ORIGIN('ArchiveURL'), nil ) .. ArchiveFormat, ArchiveDate } );
            if not is_set(OriginalURL) then
                Archived = Archived .. " " .. set_error('archive_missing_url');                               
            end
        elseif is_set(OriginalURL) then                                            -- DeadURL is empty, 'yes', 'true', 'y', 'unfit', 'usurped'
            local arch_text = cfg.messages['archived-dead'];
            if sepc ~= "." then arch_text = arch_text:lower() end
            if in_array (DeadURL, {'unfit', 'usurped', 'bot: unknown'}) then
                Archived = sepc .. " " .. 'Archived from the original on ' .. ArchiveDate;    -- format already styled
                if 'bot: unknown' == DeadURL then
                    add_maint_cat ('bot:_unknown');                                -- and add a category if not already added
                else
                    add_maint_cat ('unfit');                                    -- and add a category if not already added
                end
            else                                                                -- DeadURL is empty, 'yes', 'true', or 'y'
                Archived = sepc .. " " .. substitute( arch_text,
                    { external_link( OriginalURL, cfg.messages['original'], OriginalURLorigin, OriginalAccess ) .. OriginalFormat, ArchiveDate } );    -- format already styled
            end    
        else
            local arch_text = cfg.messages['archived-missing'];
            if sepc ~= "." then arch_text = arch_text:lower() end
            Archived = sepc .. " " .. substitute( arch_text,
                { set_error('archive_missing_url'), ArchiveDate } );
        end
    elseif is_set (ArchiveFormat) then
        Archived = ArchiveFormat;                                                -- if set and ArchiveURL not set ArchiveFormat has error message
    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; ''" .. safe_for_italics(LaySource) .. "''";
        else
            LaySource = "";
        end
        if sepc == '.' then
            Lay = sepc .. " " .. external_link( LayURL, cfg.messages['lay summary'], A:ORIGIN('LayURL'), nil ) .. LayFormat .. LaySource .. LayDate
        else
            Lay = sepc .. " " .. external_link( LayURL, cfg.messages['lay summary']:lower(), A:ORIGIN('LayURL'), nil ) .. LayFormat .. LaySource .. LayDate
        end            
    elseif is_set (LayFormat) then                                                -- Test if |lay-format= is given without giving a |lay-url=
        Lay = sepc .. LayFormat;                                                -- if set and LayURL not set, then LayFormat has error message
    end

    if is_set(Transcript) then
        if is_set(TranscriptURL) then
            Transcript = external_link( TranscriptURL, Transcript, TranscriptURLorigin, nil );
        end
        Transcript = sepc .. ' ' .. Transcript .. TranscriptFormat;
    elseif is_set(TranscriptURL) then
        Transcript = external_link( TranscriptURL, nil, TranscriptURLorigin, nil );
    end

    local Publisher;
    if is_set(PublicationDate) then
        PublicationDate = wrap_msg ('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
    
    -- 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_style ('italic-title', Periodical)
        else
            Periodical = wrap_style ('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;
    local tcommon2;                                                                -- used for book cite when |contributor= is set
    
    if in_array(config.CitationClass, {"journal","citation"}) and is_set(Periodical) then
        if is_set(Others) then Others = Others .. sepc .. " " end
        if 'mla' == Mode then
            tcommon = safe_join( {Conference, Periodical, Format, TitleType, Series, Language, Edition, Publisher, Agency, Volume}, sepc );
        else
            tcommon = safe_join( {Others, Title, TitleNote, Conference, Periodical, Format, TitleType, Series,
                Language, Edition, Publisher, Agency, Volume}, sepc );
        end        
    elseif in_array(config.CitationClass, {"book","citation"}) and not is_set(Periodical) then        -- special cases for book cites
        if is_set (Contributors) then                                            -- when we are citing foreword, preface, introduction, etc
            tcommon = safe_join( {Title, TitleNote}, sepc );                    -- author and other stuff will come after this and before tcommon2
            if 'mla' == Mode then
                tcommon2 = safe_join( {Conference, Periodical, Format, TitleType, Series, Language, Volume, Edition, Publisher, Agency}, sepc );
            else
                tcommon2 = safe_join( {Conference, Periodical, Format, TitleType, Series, Language, Volume, Others, Edition, Publisher, Agency}, sepc );
            end
        elseif 'mla' == Mode then
            tcommon = safe_join( {TitleNote, Conference, Periodical, Format, TitleType, Series, Language, Volume, Publisher, Agency}, sepc );
        else
            tcommon = safe_join( {Title, TitleNote, Conference, Periodical, Format, TitleType, Series, Language, Volume, Others, Edition, Publisher, Agency}, sepc );
        end

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

    elseif ('news' == config.CitationClass) and ('mla' == Mode) then            -- special case for cite news in MLA mode
        tcommon = safe_join( {Periodical, Format, TitleType, Series, Language, Edition, Agency}, sepc );

    elseif ('web' == config.CitationClass) and ('mla' == Mode) then                -- special case for cite web in MLA mode
        tcommon = safe_join( {Periodical, Format, TitleType, Series, Language,
            Edition, Publisher, Agency}, sepc );

    else                                                                        -- all other CS1 templates
        tcommon = safe_join( {Title, TitleNote, Conference, Periodical, Format, TitleType, Series, Language,
            Volume, Others, Edition, Publisher, Agency}, sepc );
    end
    
    if #ID_list > 0 then
        ID_list = safe_join( { sepc .. " ",  table.concat( ID_list, sepc .. " " ), ID }, sepc );
    else
        ID_list = ID;
    end
    
    local idcommon = safe_join( { ID_list, URL, Archived, AccessDate, Via, SubscriptionRequired, Lay, Quote }, sepc );
    local text;
    local pgtext = Position .. Sheet .. Sheets .. Page .. Pages .. At;

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

    -- Now enclose the whole thing in a <cite/> element
    local options = {};
    
    if is_set(config.CitationClass) and config.CitationClass ~= "citation" then
        options.class = config.CitationClass;
        options.class = "citation " .. config.CitationClass;                    -- class=citation required for blue highlight when used with |ref=
    else
        options.class = "citation";
    end
    
    if is_set(Ref) and Ref:lower() ~= "none" then                                -- set reference anchor if appropriate
        local id = Ref
        if ('harv' == Ref ) then
            local namelist = {};                                                -- holds selected contributor, author, editor name list
            local year = first_set ({Year, anchor_year}, 2);                    -- Year first for legacy citations and for YMD dates that require disambiguation

            if #c > 0 then                                                        -- if there is a contributor list
                namelist = c;                                                    -- select it
            elseif #a > 0 then                                                    -- or an author list
                namelist = a;
            elseif #e > 0 then                                                    -- or an editor list
                namelist = e;
            end
            if #namelist > 0 then                                                -- if there are names in namelist
                id = anchor_id (namelist, year);                                -- go make the CITEREF anchor
            else
                id = '';                                                        -- unset
            end
        end
        options.id = id;
    end
    
    if string.len(text:gsub("<span[^>/]*>(.-)</span>", "%1"):gsub("%b<>","")) <= 2 then    -- remove <span> tags and other html-like markup; then get length of what remains
        z.error_categories = {};
        text = set_error('empty_citation');
        z.message_tail = {};
    end
    
    if is_set(options.id) then                                                    -- here we wrap the rendered citation in <cite ...>...</cite> tags
        text = substitute (cfg.presentation['cite-id'], {mw.uri.anchorEncode(options.id), mw.text.nowiki(options.class), text});    -- when |ref= is set
    else
        text = substitute (cfg.presentation['cite'], {mw.text.nowiki(options.class), text});    -- all other cases
    end        

    text = text .. substitute (cfg.presentation['ocins'], {OCinSoutput});        -- append metadata to the citation
    
    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 .. error_comment( v[1], v[2] );
                else
                    text = text .. error_comment( v[1] .. "; ", v[2] );
                end
            end
        end
    end

    if #z.maintenance_cats ~= 0 then
        text = text .. '<span class="citation-comment" style="display:none; color:#33aa33; margin-left:0.3em">';
        for _, v in ipairs( z.maintenance_cats ) do                                -- append maintenance categories
            text = text .. v .. ' ([[:Category:' .. v ..'|link]])';
        end
        text = text .. '</span>';                                                -- maintenance mesages (realy just the names of the categories for now)
    end
    
    no_tracking_cats = no_tracking_cats:lower();
    if in_array(no_tracking_cats, {"", "no", "false", "n"}) then
        for _, v in ipairs( z.error_categories ) do
            text = text .. '[[Category:' .. v ..']]';
        end
        for _, v in ipairs( z.maintenance_cats ) do                                -- append maintenance categories
            text = text .. '[[Category:' .. v ..']]';
        end
        for _, v in ipairs( z.properties_cats ) do                                -- append maintenance categories
            text = text .. '[[Category:' .. v ..']]';
        end
    end
    
    return text
end


--[[--------------------------< C S 1 . C I T A T I O N >------------------------------------------------------

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

]]

function cs1.citation(frame)
    Frame = frame;                                                                -- save a copy incase we need to display an error message in preview mode
    local pframe = frame:getParent()
    local validation, utilities, identifiers, metadata;
    
    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 support modules
        whitelist = mw.loadData ('Module:Citation/CS1/Whitelist/sandbox');
        utilities = require ('Module:Citation/CS1/Utilities/sandbox');
        validation = require ('Module:Citation/CS1/Date_validation/sandbox');
        identifiers = require ('Module:Citation/CS1/Identifiers/sandbox');
        metadata = require ('Module:Citation/CS1/COinS/sandbox');
        
    else                                                                        -- otherwise
        cfg = mw.loadData ('Module:Citation/CS1/Configuration');                -- load live versions of support modules
        whitelist = mw.loadData ('Module:Citation/CS1/Whitelist');
        utilities = require ('Module:Citation/CS1/Utilities');
        validation = require ('Module:Citation/CS1/Date_validation');
        identifiers = require ('Module:Citation/CS1/Identifiers');
        metadata = require ('Module:Citation/CS1/COinS');
    end

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

    dates = validation.dates;                                                    -- imported functions from Module:Citation/CS1/Date validation
    year_date_check = validation.year_date_check;
    reformat_dates = validation.reformat_dates;
    date_hyphen_to_dash = validation.date_hyphen_to_dash;
    
    is_set = utilities.is_set;                                                    -- imported functions from Module:Citation/CS1/Utilities
    in_array = utilities.in_array;
    substitute = utilities.substitute;
    error_comment = utilities.error_comment;
    set_error = utilities.set_error;
    select_one = utilities.select_one;
    add_maint_cat = utilities.add_maint_cat;
    wrap_style = utilities.wrap_style;
    safe_for_italics = utilities.safe_for_italics;
    remove_wiki_link = utilities.remove_wiki_link;

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

    extract_ids = identifiers.extract_ids;                                        -- imported functions from Module:Citation/CS1/Identifiers
    build_id_list = identifiers.build_id_list;
    is_embargoed = identifiers.is_embargoed;
    extract_id_access_levels = identifiers.extract_id_access_levels;
    
    make_coins_title = metadata.make_coins_title;                                -- imported functions from Module:Citation/CS1/COinS
    get_coins_pages = metadata.get_coins_pages;
    COinS = metadata.COinS;

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

    local config = {};                                                            -- table to store parameters from the module {{#invoke:}}
    for k, v in pairs( frame.args ) do
        config[k] = v;
--        args[k] = v;                                                            -- debug tool that allows us to render a citation from module {{#invoke:}}
    end    

    local capture;                                                                -- the single supported capture when matching unknown parameters using patterns
    for k, v in pairs( pframe.args ) do
        if v ~= '' then
            if not validate( k, config.CitationClass ) then            
                error_text = "";
                if type( k ) ~= 'string' then
                    -- Exclude empty numbered parameters
                    if v:match("%S+") ~= nil then
                        error_text, error_state = set_error( 'text_ignored', {v}, true );
                    end
                elseif validate( k:lower(), config.CitationClass ) then
                    error_text, error_state = set_error( 'parameter_ignored_suggest', {k, k:lower()}, true );
                else
                    if nil == suggestions.suggestions then                        -- if this table is nil then we need to load it
                        if nil ~= string.find (frame:getTitle(), 'sandbox', 1, true) then            -- did the {{#invoke:}} use sandbox version?
                            suggestions = mw.loadData( 'Module:Citation/CS1/Suggestions/sandbox' );    -- use the sandbox version
                        else
                            suggestions = mw.loadData( 'Module:Citation/CS1/Suggestions' );            -- use the live version
                        end
                    end
                    for pattern, param in pairs (suggestions.patterns) do        -- loop through the patterns to see if we can suggest a proper parameter
                        capture = k:match (pattern);                            -- the whole match if no caputre in pattern else the capture if a match
                        if capture then                                            -- if the pattern matches
                            param = substitute( param, capture );                -- add the capture to the suggested parameter (typically the enumerator)
                            error_text, error_state = set_error( 'parameter_ignored_suggest', {k, param}, true );    -- set the error message
                        end
                    end
                    if not is_set (error_text) then                                -- couldn't match with a pattern, is there an expicit suggestion?
                        if suggestions.suggestions[ k:lower() ] ~= nil then
                            error_text, error_state = set_error( 'parameter_ignored_suggest', {k, suggestions.suggestions[ k:lower() ]}, true );
                        else
                            error_text, error_state = set_error( 'parameter_ignored', {k}, true );
                            v = '';                                                -- unset value assigned to unrecognized parameters (this for the limited parameter lists)
                        end
                    end
                end                  
                if error_text ~= '' then
                    table.insert( z.message_tail, {error_text, error_state} );
                end                
            end
            missing_pipe_check (v);                                                -- do we think that there is a parameter that is missing a pipe?
            
            args[k] = v;
        elseif args[k] ~= nil or (k == 'postscript') then
            args[k] = v;
        end        
    end    

    for k, v in pairs( args ) do
        if 'string' == type (k) then                                            -- don't evaluate positional parameters
            has_invisible_chars (k, v);
        end
    end
    return citation0( config, args)
end

return cs1;