Module:Citation/CS1

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

require("strict")

--[[----------------< F O R W A R D _ D E C L A R A T I O N S >-----------------
  Each of these counts against the Lua upper value limit.
]]
local validation   -- Functions in Module:Citation/CS1/Date_validation.
local utilities    -- Functions in Module:Citation/CS1/Utilities.
local z = {}       -- Table of tables in Module:Citation/CS1/Utilities.
local identifiers  -- Functions and tables in Module:Citation/CS1/Identifiers.
local metadata     -- Functions in Module:Citation/CS1/COinS.
-- Table of configuration tables defined in Module:Citation/CS1/Configuration.
local cfg = {}
-- Supertable of valid template parameters; from Module:Citation/CS1/Whitelist.
local whitelist = {}

--[[----------------< P A G E _ S C O P E _ V A R I A B L E S >-----------------
  Declare variables here that have page-wide scope that are not brought in from
  other modules, that are created here and used here; booleans all.
]]
local added_deprecated_cat      -- Only add category once.
local added_vanc_errs           -- Only emit one Vanc. error/category.
-- Only emit one generic name err./cat. & stop testing after first error occurs.
local added_generic_name_errs
-- Only emit one numeric name err./cat. & stop testing after first error occurs.
local added_numeric_name_errs
local added_numeric_name_maint  -- Only emit one numeric name maint. category.
-- True when previewing article, false when previewing the module.
local is_preview_mode
local is_sandbox                -- Using sandbox modules sets this to true.

--[[-------------------------< 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 the list.
    if utilities.is_set(list[i]) then
      return list[i]   -- Return the first set list member.
    end
    i = i + 1          -- Increment to next member.
  end
end

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

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

added_vanc_errs is a Boolean declared in page scope variables above

]]
local function add_vanc_error(source, position)
    if added_vanc_errs then
        return
    end

    added_vanc_errs = true -- note that we've added this category
    utilities.set_message("err_vancouver", {source, position})
end

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

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

returns true if it does, else false

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

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

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

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

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

Also allowed are IPv4 addresses. IPv6 not supported

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

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

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

]=]

local function is_domain_name(domain)
    if not domain then
        return false -- if not set, abandon
    end

    domain = domain:gsub("^//", "") -- strip '//' from domain name if present; done here so we only have to do it once

    if not domain:match("^[%w]") then -- first character must be letter or digit
        return false
    end

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

    local patterns = {
        -- patterns that look like URLs
        "%f[%w][%w][%w%-]+[%w]%.%a%a+$", -- three or more character hostname.hostname or hostname.tld
        "%f[%w][%w][%w%-]+[%w]%.xn%-%-[%w]+$", -- internationalized domain name with ACE prefix
        "%f[%a][qxz]%.com$", -- assigned one character .com hostname (x.com times out 2015-12-10)
        "%f[%a][iq]%.net$", -- assigned one character .net hostname (q.net registered but not active 2015-12-10)
        "%f[%w][%w]%.%a%a$", -- one character hostname and ccTLD (2 chars)
        "%f[%w][%w][%w]%.%a%a+$", -- two character hostname and TLD
        "^%d%d?%d?%.%d%d?%d?%.%d%d?%d?%.%d%d?%d?", -- IPv4 address
        "[%a%d]+%:?" -- IPv6 address
    }

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

    for _, d in ipairs(cfg.single_letter_2nd_lvl_domains_t) do -- look for single letter second level domain names for these top level domains
        if domain:match("%f[%w][%w]%." .. d) then
            return true
        end
    end
    return false -- no matches, we don't know what this thing is
end

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

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

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

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

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

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

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

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

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

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

Strip off any port and path;

]]
local function split_url(url_str)
    local scheme, authority, domain

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

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

    return scheme, domain
end

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

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

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

returns false when the value contains any of these characters.

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

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

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

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

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

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

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

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

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

    if utilities.is_set(orig) then
        link = "" -- unset
        utilities.set_message("err_bad_paramlink", orig) -- URL or wikilink in |title= with |title-link=;
    end

    return link -- link if ok, empty string else
end

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

Determines whether a URL string appears to be valid.

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

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

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

    scheme, domain = split_url(url_str) -- get scheme or nil and domain or nil from URL;

    if "news:" == scheme then -- special case for newsgroups
        return domain:match("^[%a%d%+%-_]+%.[%a%d%+%-_%.]*[%a%d%+%-_]$")
    end

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

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

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

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

]=]

local function is_parameter_ext_wikilink(value)
    local scheme, domain

    if value:match("%f[%[]%[%a%S*:%S+.*%]") then -- if ext. wikilink with scheme and domain: [xxxx://yyyyy.zzz]
        scheme, domain = split_url(value:match("%f[%[]%[(%a%S*:%S+).*%]"))
    elseif value:match("%f[%[]%[//%S+.*%]") then -- if protocol-relative ext. wikilink: [//yyyyy.zzz]
        scheme, domain = split_url(value:match("%f[%[]%[(//%S+).*%]"))
    elseif value:match("%a%S*:%S+") then -- if bare URL with scheme; may have leading or trailing plain text
        scheme, domain = split_url(value:match("(%a%S*:%S+)"))
    elseif value:match("^//%S+") or value:match("%s//%S+") then -- if protocol-relative bare URL: //yyyyy.zzz; authority indicator (//) must be be preceded nothing or by whitespace
        scheme, domain = split_url(value:match("(//%S+)")) -- what is left should be the domain
    else
        return false -- didn't find anything that is obviously a URL
    end

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

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

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

]]
local function check_for_url(parameter_list, error_list)
    for k, v in pairs(parameter_list) do -- for each parameter in the list
        if is_parameter_ext_wikilink(v) then -- look at the value; if there is a URL add an error message
            table.insert(error_list, utilities.wrap_style("parameter", k))
        end
    end
end

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

Escape sequences for content that will be used for URL descriptions

]]
local function safe_for_url(str)
    if str:match("%[%[.-%]%]") ~= nil then
        utilities.set_message("err_wikilink_in_url", {})
    end

    return str:gsub(
        "[%[%]\n]",
        {
            ["["] = "&#91;",
            ["]"] = "&#93;",
            ["\n"] = " "
        }
    )
end

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

Format an external link with error checking

]]
local function external_link(URL, label, source, access)
    local err_msg = ""
    local domain
    local path
    local base_url

    if not utilities.is_set(label) then
        label = URL
        if utilities.is_set(source) then
            utilities.set_message("err_bare_url_missing_title", {utilities.wrap_style("parameter", source)})
        else
            error(cfg.messages["bare_url_no_origin"]) -- programmer error; valid parameter name does not have matching meta-parameter
        end
    end
    if not check_url(URL) then
        utilities.set_message("err_bad_url", {utilities.wrap_style("parameter", source)})
    end

    domain, path = URL:match("^([/%.%-%+:%a%d]+)([/%?#].*)$") -- split the URL into scheme plus domain and path
    if path then -- if there is a path portion
        path = path:gsub("[%[%]]", {["["] = "%5b", ["]"] = "%5d"}) -- replace '[' and ']' with their percent-encoded values
        URL = table.concat({domain, path}) -- and reassemble
    end

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

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

    return base_url
end

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

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

added_deprecated_cat is a Boolean declared in page scope variables above

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

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

Apply kerning to open the space between the quote mark provided by the module and a leading or trailing quote
mark contained in a |title= or |chapter= parameter's value.

This function will positive kern either single or double quotes:
	"'Unkerned title with leading and trailing single quote marks'"
	" 'Kerned title with leading and trailing single quote marks' " (in real life the kerning isn't as wide as this example)
Double single quotes (italic or bold wiki-markup) are not kerned.

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

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

]=]

local function kern_quotes(str)
    local cap = ""
    local wl_type, label, link

    wl_type, label, link = utilities.is_wikilink(str) -- wl_type is: 0, no wl (text in label variable); 1, [[D]]; 2, [[L|D]]

    if 1 == wl_type then -- [[D]] simple wikilink with or without quote marks
        if mw.ustring.match(str, '%[%[["“”\'‘’].+["“”\'‘’]%]%]') then -- leading and trailing quote marks
            str = utilities.substitute(cfg.presentation["kern-left"], str)
            str = utilities.substitute(cfg.presentation["kern-right"], str)
        elseif mw.ustring.match(str, '%[%[["“”\'‘’].+%]%]') then -- leading quote marks
            str = utilities.substitute(cfg.presentation["kern-left"], str)
        elseif mw.ustring.match(str, '%[%[.+["“”\'‘’]%]%]') then -- trailing quote marks
            str = utilities.substitute(cfg.presentation["kern-right"], str)
        end
    else -- plain text or [[L|D]]; text in label variable
        label = mw.ustring.gsub(label, "[“”]", '"') -- replace “” (U+201C & U+201D) with " (typewriter double quote mark)
        label = mw.ustring.gsub(label, "[‘’]", "'") -- replace ‘’ (U+2018 & U+2019) with ' (typewriter single quote mark)

        cap = mw.ustring.match(label, '^(["\'][^\'].+)') -- match leading double or single quote but not doubled single quotes (italic markup)
        if utilities.is_set(cap) then
            label = utilities.substitute(cfg.presentation["kern-left"], cap)
        end

        cap = mw.ustring.match(label, '^(.+[^\']["\'])$') -- match trailing double or single quote but not doubled single quotes (italic markup)
        if utilities.is_set(cap) then
            label = utilities.substitute(cfg.presentation["kern-right"], cap)
        end

        if 2 == wl_type then
            str = utilities.make_wikilink(link, label) -- reassemble the wikilink
        else
            str = label
        end
    end
    return str
end

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

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

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

|script-title= provides a unique feature.  The value in |script-title= may be prefixed with a two-character ISO 639-1 language code and a colon:
	|script-title=ja:*** *** (where * represents a Japanese character)
Spaces between the two-character code and the colon and the colon and the first script character are allowed:
	|script-title=ja : *** ***
	|script-title=ja: *** ***
	|script-title=ja :*** ***
Spaces preceding the prefix are allowed: |script-title = ja:*** ***

The prefix is checked for validity.  If it is a valid ISO 639-1 language code, the lang attribute (lang="ja") is added to the <bdi> tag so that browsers can
know the language the tag contains.  This may help the browser render the script more correctly.  If the prefix is invalid, the lang attribute
is not added.  At this time there is no error message for this condition.

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

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

    return script_value
end

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

]]
local function format_periodical(script_periodical, script_periodical_source, periodical, trans_periodical)
    if not utilities.is_set(periodical) then
        periodical = "" -- to be safe for concatenation
    else
        periodical = utilities.wrap_style("italic-title", periodical) -- style
    end

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

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

    return periodical
end

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

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

]]
local function format_chapter_title(
    script_chapter,
    script_chapter_source,
    chapter,
    chapter_source,
    trans_chapter,
    trans_chapter_source,
    chapter_url,
    chapter_url_source,
    no_quotes,
    access)
    local ws_url, ws_label, L = wikisource_url_make(chapter) -- make a wikisource URL and label from a wikisource interwiki link
    if ws_url then
        ws_label = ws_label:gsub("_", " ") -- replace underscore separators with space characters
        chapter = ws_label
    end

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

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

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

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

    return chapter
end

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

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

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

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

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

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

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

    for _, invisible_char in ipairs(cfg.invisible_chars) do
        local char_name = invisible_char[1] -- the character or group name
        local pattern = invisible_char[2] -- the pattern used to find it
        position, _, capture = mw.ustring.find(v, pattern) -- see if the parameter value contains characters that match the pattern

        if position and (cfg.invisible_defs.zwj == capture) then -- if we found a zero-width joiner character
            if mw.ustring.find(v, cfg.indic_script) then -- it's ok if one of the Indic scripts
                position = nil -- unset position
            elseif cfg.emoji_t[mw.ustring.codepoint(v, position + 1)] then -- is zwj followed by a character listed in emoji{}?
                position = nil -- unset position
            end
        end

        if position then
            if
                "nowiki" == capture or "math" == capture or -- nowiki and math stripmarkers (not an error condition)
                    ("templatestyles" == capture and utilities.in_array(param, {"id", "quote"}))
             then -- templatestyles stripmarker allowed in these parameters
                stripmarker = true -- set a flag
            elseif true == stripmarker and cfg.invisible_defs.del == capture then -- because stripmakers begin and end with the delete char, assume that we've found one end of a stripmarker
                position = nil -- unset
            else
                local err_msg
                if capture and not (cfg.invisible_defs.del == capture or cfg.invisible_defs.zwj == capture) then
                    err_msg = capture .. " " .. char_name
                else
                    err_msg = char_name .. " " .. "character"
                end

                utilities.set_message(
                    "err_invisible_char",
                    {err_msg, utilities.wrap_style("parameter", param), position}
                ) -- add error message
                return -- and done with this parameter
            end
        end
    end
end

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

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

]]
local function argument_wrapper(args)
    local origin = {}

    return setmetatable(
        {
            ORIGIN = function(self, k)
                local dummy = self[k] -- force the variable to be loaded.
                return origin[k]
            end
        },
        {
            __index = function(tbl, k)
                if origin[k] ~= nil then
                    return nil
                end

                local args, list, v = args, cfg.aliases[k]

                if type(list) == "table" then
                    v, origin[k] = utilities.select_one(args, list, "err_redundant_parameters")
                    if origin[k] == nil then
                        origin[k] = "" -- Empty string, not nil
                    end
                elseif list ~= nil then
                    v, origin[k] = args[list], list
                else
                    -- maybe let through instead of raising an error?
                    -- v, origin[k] = args[k], k;
                    error(cfg.messages["unknown_argument_map"] .. ": " .. k)
                end

                -- Empty strings, not nil;
                if v == nil then
                    v = ""
                    origin[k] = ""
                end

                tbl = rawset(tbl, k, v)
                return v
            end
        }
    )
end

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

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

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

]]
local function nowrap_date(date)
    local cap = ""
    local cap2 = ""

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

    return date
end

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

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

]]
local function set_titletype(cite_class, title_type)
    if utilities.is_set(title_type) then
        if "none" == cfg.keywords_xlate[title_type] then
            title_type = "" -- if |type=none then type parameter not displayed
        end
        return title_type -- if |type= has been set to any other value use that value
    end

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

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

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

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

    local str = "" -- the output string
    local comp = "" -- what does 'comp' mean?
    local end_chr = ""
    local trim
    for _, value in ipairs(tbl) do
        if value == nil then
            value = ""
        end

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

                if trim then
                    if value ~= comp then -- value does not equal comp when value contains HTML markup
                        local dup2 = duplicate_char
                        if f.match(dup2, "%A") then
                            dup2 = "%" .. dup2
                        end -- if duplicate_char not a letter then escape it

                        value = f.gsub(value, "(%b<>)" .. dup2, "%1", 1) -- remove duplicate_char if it follows HTML markup
                    else
                        value = f.sub(value, 2, -1) -- remove duplicate_char when it is first character
                    end
                end
            end
            str = str .. value -- add it to the output string
        end
    end
    return str
end

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

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

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

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

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

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

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

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

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

]]
local function is_good_vanc_name(last, first, suffix, position)
    if not suffix then
        if first:find("[,%s]") then -- when there is a space or comma, might be first name/initials + generational suffix
            first = first:match("(.-)[,%s]+") -- get name/initials
            suffix = first:match("[,%s]+(.+)$") -- get generational suffix
        end
    end
    if utilities.is_set(suffix) then
        if not is_suffix(suffix) then
            add_vanc_error(cfg.err_msg_supl.suffix, position)
            return false -- not a name with an appropriate suffix
        end
    end
    if
        nil ==
            mw.ustring.find(
                last,
                "^[A-Za-z\195\128-\195\150\195\152-\195\182\195\184-\198\191\199\132-\201\143\225\184\128-\225\187\191%-%s%']*$"
            ) 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\225\184\128-\225\187\191%-%s%'%.]*$"
                )
     then
        add_vanc_error(cfg.err_msg_supl["non-Latin char"], position)
        return false -- not a string of Latin characters; Vancouver requires Romanization
    end
    return true
end

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

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

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

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

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

]]
local function reduce_to_initials(first, position)
    if first:find(",", 1, true) then
        return first -- commas not allowed; abandon
    end

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

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

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

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

    names_t = mw.text.split(first, "[%s%-]+") -- split into a sequence of names and possible suffix

    while names_t[i] do -- loop through the sequence
        if 1 < i and names_t[i]:match("[%dJS][%drndth]+%.?$") then -- if not the first name, and looks like a suffix (may have trailing dot)
            names_t[i] = names_t[i]:gsub("%.", "") -- remove terminal dot if present
            if is_suffix(names_t[i]) then -- if a legitimate suffix
                table.insert(initials_t, " " .. names_t[i]) -- add a separator space, insert at end of initials sequence
                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_t, mw.ustring.sub(names_t[i], 1, 1)) -- insert the initial at end of initials sequence
        end
        i = i + 1 -- bump the counter
    end

    return table.concat(initials_t) -- Vancouver format does not include spaces.
end

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

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

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

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

    local prefix_patterns_linked_t = {
        -- sequence of valid interwiki and inter project prefixen
        "^%[%[:([dsw]):(%l%l+):", -- wikilinked; project and language prefixes
        "^%[%[:(%l%l+):([dsw]):", -- wikilinked; language and project prefixes
        "^%[%[:([dsw]):", -- wikilinked; project prefix
        "^%[%[:(%l%l+):" -- wikilinked; language prefix
    }

    local prefix_patterns_unlinked_t = {
        -- sequence of valid interwiki and inter project prefixen
        "^:([dsw]):(%l%l+):", -- project and language prefixes
        "^:(%l%l+):([dsw]):", -- language and project prefixes
        "^:([dsw]):", -- project prefix
        "^:(%l%l+):" -- language prefix
    }

    local cap1, cap2
    for _, pattern in ipairs((is_link and prefix_patterns_linked_t) or prefix_patterns_unlinked_t) do
        cap1, cap2 = value:match(pattern)
        if cap1 then
            break -- found a match so stop looking
        end
    end

    if cap1 and cap2 then -- when both then :project:language: or :language:project: (both forms allowed)
        if 1 == #cap1 then -- length == 1 then :project:language:
            if cfg.inter_wiki_map[cap2] then -- is language prefix in the interwiki map?
                return cap1, cap2 -- return interwiki project and interwiki language
            end
        else -- here when :language:project:
            if cfg.inter_wiki_map[cap1] then -- is language prefix in the interwiki map?
                return cap2, cap1 -- return interwiki project and interwiki language
            end
        end
        return nil -- unknown interwiki language
    elseif not (cap1 or cap2) then -- both are nil?
        return nil -- we got something that looks like a project prefix but isn't; return fail
    elseif 1 == #cap1 then -- here when one capture
        return cap1, nil -- length is 1 so return project, nil language
    else -- here when one capture and its length it more than 1
        if cfg.inter_wiki_map[cap1] then -- is language prefix in the interwiki map?
            return nil, cap1 -- return nil project, language
        end
    end
end

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

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

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

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

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

    if "vanc" == format then -- Vancouver-like name styling?
        sep = cfg.presentation["sep_nl_vanc"] -- name-list separator between names is a comma
        namesep = cfg.presentation["sep_name_vanc"] -- last/first separator is a space
    else
        sep = cfg.presentation["sep_nl"] -- name-list separator between names is a semicolon
        namesep = cfg.presentation["sep_name"] -- last/first separator is <comma><space>
    end

    if sep:sub(-1, -1) ~= " " then
        sep = sep .. " "
    end
    if utilities.is_set(maximum) and maximum < 1 then
        return "", 0
    end -- returned 0 is for EditorCount; not used for other names

    for i, person in ipairs(people) do
        if utilities.is_set(person.last) then
            local mask = person.mask
            local one
            local sep_one = sep

            if utilities.is_set(maximum) and i > maximum then
                etal = true
                break
            end

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

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

                table.insert(name_list, one) -- add it to the list of names
                table.insert(name_list, sep_one) -- add the proper name-list separator
            end
        end
    end

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

    local result = table.concat(name_list) -- construct list
    if etal and utilities.is_set(result) then -- etal may be set by |display-authors=etal but we might not have a last-first list
        result = result .. sep .. cfg.messages["et al"] -- we've got a last-first list and etal so add et al.
    end

    return result, count -- return name-list string and count of number of names (count used for editor names only)
end

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

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

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

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

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

construct <cite> tag class attribute for this citation.

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

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

    return table.concat(class_t, " ") -- make a big string and done
end

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

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

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

]]
local function name_has_etal(name, etal, nocat, param)
    if utilities.is_set(name) then -- name can be nil in which case just return
        local patterns = cfg.et_al_patterns -- get patterns from configuration

        for _, pattern in ipairs(patterns) do -- loop through all of the patterns
            if name:match(pattern) then -- if this 'et al' pattern is found in name
                name = name:gsub(pattern, "") -- remove the offending text
                etal = true -- set flag (may have been set previously here or by |display-<names>=etal)
                if not nocat then -- no categorization for |vauthors=
                    utilities.set_message("err_etal", {param}) -- and set an error if not added
                end
            end
        end
    end

    return name, etal
end

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

Add an error message and category when <name> parameter value does not contain letters.  

Add a maintenance category when <name> parameter value has numeric characters mixed with characters that are 
not numeric characters; could be letters and/or punctuation characters.

This function will only emit one error and one maint message for the current template.  Does not emit both error
and maint messages/categories for the same parameter value.

returns nothing

]]
local function name_is_numeric(name, name_alias, list_name)
    local patterns = {
        "^%D+%d", -- <name> must have digits preceded by other characters
        "^%D*%d+%D+" -- <name> must have digits followed by other characters
    }

    if not added_numeric_name_errs and mw.ustring.match(name, "^[%A]+$") then -- if we have not already set an error message and <name> does not have any alpha characters
        utilities.set_message("err_numeric_names", name_alias) -- add an error message
        added_numeric_name_errs = true -- set the flag so we emit only one error message
        return -- when here no point in further testing; abandon
    end

    if not added_numeric_name_maint then -- if we have already set a maint message
        for _, pattern in ipairs(patterns) do -- spin through list of patterns
            if mw.ustring.match(name, pattern) then -- digits preceded or followed by anything but digits; %D+ includes punctuation
                utilities.set_message("maint_numeric_names", cfg.special_case_translation[list_name]) -- add a maint cat for this template
                added_numeric_name_maint = true -- set the flag so we emit only one maint message
                return -- when here no point in further testing; abandon
            end
        end
    end
end

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

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

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

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

returns nothing

]]
local function name_has_mult_names(name, list_name, limit)
    local _, commas, semicolons, nbsps
    limit = limit and limit or 1
    if utilities.is_set(name) then
        _, commas = name:gsub(",", "") -- count the number of commas
        _, semicolons = name:gsub(";", "") -- count the number of semicolons
        -- nbsps probably should be its own separate count rather than merged in
        -- some way with semicolons because Lua patterns do not support the
        -- grouping operator that regex does, which means there is no way to add
        -- more entities to escape except by adding more counts with the new
        -- entities
        _, nbsps = name:gsub("&nbsp;", "") -- count nbsps

        -- There is exactly 1 semicolon per &nbsp; entity, so subtract nbsps
        -- from semicolons to 'escape' them. If additional entities are added,
        -- they also can be subtracted.
        if limit < commas or 0 < (semicolons - nbsps) then
            utilities.set_message("maint_mult_names", cfg.special_case_translation[list_name]) -- add a maint message
        end
    end
end

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

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

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

Each of the 'accept' and 'reject' sequence tables hold tables for en.wiki (['en']) and local.wiki (['local'])
that each can hold a test sequence table  The sequence table holds, at index [1], a test pattern, and, at index
[2], a boolean control value.  The control value tells string.find() or mw.ustring.find() to do plain-text search (true)
or a pattern search (false).  The intent of all this complexity is to make these searches as fast as possible so
that we don't run out of processing time on very large articles.

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

]=]

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

    local function test(val, test_t, wiki) -- local function to do the testing; <wiki> selects lower() and find() functions
        val = test_t[2] and str_lower[wiki](value) or val -- when <test_t[2]> set to 'true', plaintext search using lowercase value
        return str_find[wiki](val, test_t[1], 1, test_t[2]) -- return nil when not found or matched
    end

    local test_types_t = {"accept", "reject"} -- test accept patterns first, then reject patterns
    local wikis_t = {"en", "local"} -- do tests for each of these keys; en.wiki first, local.wiki second

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

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

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

]]
local function name_is_generic(name, name_alias)
    if not added_generic_name_errs and is_generic("generic_names", name) then
        utilities.set_message("err_generic_name", name_alias) -- set an error message
        added_generic_name_errs = true
    end
end

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

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

]]
local function name_checks(last, first, list_name, last_alias, first_alias)
    local accept_name

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

        if not accept_name then -- <last> not wrapped in accept-as-written markup
            name_has_mult_names(last, list_name) -- check for multiple names in the parameter
            name_is_numeric(last, last_alias, list_name) -- check for names that have no letters or are a mix of digits and other characters
            name_is_generic(last, last_alias) -- check for names found in the generic names list
        end
    end

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

        if not accept_name then -- <first> not wrapped in accept-as-written markup
            name_has_mult_names(first, list_name, 0) -- check for multiple names in the parameter; 0 is number of allowed commas in a given name
            name_is_numeric(first, first_alias, list_name) -- check for names that have no letters or are a mix of digits and other characters
            name_is_generic(first, first_alias) -- check for names found in the generic names list
        end
        local wl_type, D = utilities.is_wikilink(first)
        if 0 ~= wl_type then
            first = D
            utilities.set_message("err_bad_paramlink", first_alias)
        end
    end

    return last, first -- done
end

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

Gets name list from the input arguments

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

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

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

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

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

        if last then -- error check |lastn= alias for unknown interwiki link prefix; done here because this is where we have the parameter name
            local project, language = interwiki_prefixen_get(last, true) -- true because we expect interwiki links in |lastn= to be wikilinked
            if nil == project and nil == language then -- when both are nil
                utilities.set_message("err_bad_paramlink", last_alias) -- not known, emit an error message	-- TODO: err_bad_interwiki?
                last = utilities.remove_wiki_link(last) -- remove wikilink markup; show display value only
            end
        end

        if link then -- error check |linkn= alias for unknown interwiki link prefix
            local project, language = interwiki_prefixen_get(link, false) -- false because wiki links in |author-linkn= is an error
            if nil == project and nil == language then -- when both are nil
                utilities.set_message("err_bad_paramlink", link_alias) -- not known, emit an error message	-- TODO: err_bad_interwiki?
                link = nil -- unset so we don't link
                link_alias = nil
            end
        end

        last, etal = name_has_etal(last, etal, false, last_alias) -- find and remove variations on et al.
        first, etal = name_has_etal(first, etal, false, first_alias) -- find and remove variations on et al.
        last, first = name_checks(last, first, list_name, last_alias, first_alias) -- multiple names, extraneous annotation, etc. checks

        if first and not last then -- if there is a firstn without a matching lastn
            local alias = first_alias:find("given", 1, true) and "given" or "first" -- get first or given form of the alias
            utilities.set_message(
                "err_first_missing_last",
                {
                    first_alias, -- param name of alias missing its mate
                    first_alias:gsub(alias, {["first"] = "last", ["given"] = "surname"}) -- make param name appropriate to the alias form
                }
            ) -- add this error message
        elseif not first and not last then -- if both firstn and lastn aren't found, are we done?
            count = count + 1 -- number of times we haven't found last and first
            if 2 <= count then -- two missing names and we give up
                break -- normal exit or there is a two-name hole in the list; can't tell which
            end
        else -- we have last with or without a first
            local result
            link = link_title_ok(link, link_alias, last, last_alias) -- check for improper wiki-markup

            if first then
                link = link_title_ok(link, link_alias, first, first_alias) -- check for improper wiki-markup
            end

            names[n] = {last = last, first = first, link = link, mask = mask, corporate = false} -- add this name to our names list (corporate for |vauthors= only)
            n = n + 1 -- point to next location in the names table
            if 1 == count then -- if the previous name was missing
                utilities.set_message("err_missing_name", {list_name:match("(%w+)List"):lower(), i - 1}) -- add this error message
            end
            count = 0 -- reset the counter, we're looking for two consecutive missing names
        end
        i = i + 1 -- point to next args location
    end

    return names, etal -- all done, return our list of names and the etal flag
end

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

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

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

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

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

    name = cfg.lang_tag_remap[lang_param_lc] -- assume <lang_param_lc> is a tag; attempt to get remapped language name
    if name then -- when <name>, <lang_param> is a tag for a remapped language name
        if cfg.lang_name_remap[name:lower()][2] ~= lang_param_lc then
            utilities.set_message("maint_unknown_lang") -- add maint category if not already added
            return name, cfg.lang_name_remap[name:lower()][2] -- so return name and tag from lang_name_remap[name]; special case to xlate sr-ec and sr-el to sr-cyrl and sr-latn
        end
        return name, lang_param_lc -- so return <name> from remap and <lang_param_lc>
    end

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

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

    name = cfg.mw_languages_by_tag_t[lang_param_lc] -- assume that <lang_param_lc> is a tag; attempt to get its matching language name

    if name then
        return name, lang_param_lc -- <lang_param_lc> is a tag so return it and <name>
    end

    tag = cfg.mw_languages_by_name_t[lang_param_lc] -- assume that <lang_param_lc> is a language name; attempt to get its matching tag

    if tag then
        return cfg.mw_languages_by_tag_t[tag], tag -- <lang_param_lc> is a name so return the name from the table and <tag>
    end

    tag = lang_param_lc:match("^(%a%a%a?)%-.*") -- is <lang_param_lc> an IETF-like tag that MediaWiki doesn't recognize? <tag> gets the language subtag; nil else

    if tag then
        name = cfg.mw_languages_by_tag_t[tag] -- attempt to get a language name using the shortened <tag>
        if name then
            return name, tag -- <lang_param_lc> is an unrecognized IETF-like tag so return <name> and language subtag
        end
    end
end

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

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

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

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

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

]]
local function language_parameter(lang)
    local tag  -- some form of IETF-like language tag; language subtag with optional region, sript, vatiant, etc subtags
    local lang_subtag  -- ve populates |language= with mostly unecessary region subtags the MediaWiki does not recognize; this is the base language subtag
    local name  -- the language name
    local language_list = {} -- table of language names to be rendered
    local names_t = {} -- table made from the value assigned to |language=

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

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

    for _, lang in ipairs(names_t) do -- reuse lang here because we don't yet know if lang is a language name or a language tag
        name, tag = name_tag_get(lang) -- attempt to get name/tag pair for <lang>; <name> has proper capitalization; <tag> is lowercase

        if utilities.is_set(tag) then
            lang_subtag = tag:gsub("^(%a%a%a?)%-.*", "%1") -- for categorization, strip any IETF-like tags from language tag

            if cfg.this_wiki_code ~= lang_subtag then -- when the language is not the same as this wiki's language
                if 2 == lang_subtag:len() then -- and is a two-character tag
                    utilities.add_prop_cat("foreign-lang-source", {name, tag}, lang_subtag) -- categorize it; tag appended to allow for multiple language categorization
                else -- or is a recognized language (but has a three-character tag)
                    utilities.add_prop_cat("foreign-lang-source-2", {lang_subtag}, lang_subtag) -- categorize it differently TODO: support multiple three-character tag categories per cs1|2 template?
                end
            elseif cfg.local_lang_cat_enable then -- when the language and this wiki's language are the same and categorization is enabled
                utilities.add_prop_cat("local-lang-source", {name, lang_subtag}) -- categorize it
            end
        else
            name = lang -- return whatever <lang> has so that we show something
            utilities.set_message("maint_unknown_lang") -- add maint category if not already added
        end

        table.insert(language_list, name)
        name = "" -- so we can reuse it
    end

    name = utilities.make_sep_list(#language_list, language_list)
    if (1 == #language_list) and (lang_subtag == cfg.this_wiki_code) then -- when only one language, find lang name in this wiki lang name; for |language=en-us, 'English' in 'American English'
        return "" -- if one language and that language is this wiki's return an empty string (no annotation)
    end
    return (" " .. wrap_msg("language", name)) -- otherwise wrap with '(in ...)'
    --[[ TODO: should only return blank or name rather than full list
	so we can clean up the bunched parenthetical elements Language, Type, Format
	]]
end

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

Gets the default CS style configuration for the given mode.
Returns default separator and either postscript as passed in or the default.
In CS1, the default postscript and separator are '.'.
In CS2, the default postscript is the empty string and the default separator is ','.

]]
local function set_cs_style(postscript, mode)
    if utilities.is_set(postscript) then
        -- emit a maintenance message if user postscript is the default cs1 postscript
        -- we catch the opposite case for cs2 in set_style
        if mode == "cs1" and postscript == cfg.presentation["ps_" .. mode] then
            utilities.set_message("maint_postscript")
        end
    else
        postscript = cfg.presentation["ps_" .. mode]
    end
    return cfg.presentation["sep_" .. mode], postscript
end

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

Sets the separator and postscript styles. Checks the |mode= first and the
#invoke CitationClass second. Removes the postscript if postscript == none.

]]
local function set_style(mode, postscript, cite_class)
    local sep
    if "cs2" == mode then
        sep, postscript = set_cs_style(postscript, "cs2")
    elseif "cs1" == mode then
        sep, postscript = set_cs_style(postscript, "cs1")
    elseif "citation" == cite_class then
        sep, postscript = set_cs_style(postscript, "cs2")
    else
        sep, postscript = set_cs_style(postscript, "cs1")
    end

    if cfg.keywords_xlate[postscript:lower()] == "none" then
        -- emit a maintenance message if user postscript is the default cs2 postscript
        -- we catch the opposite case for cs1 in set_cs_style
        if "cs2" == mode or ("cs1" ~= mode and "citation" == cite_class) then -- {{citation |title=Title |mode=cs1 |postscript=none}} should not emit maint message
            utilities.set_message("maint_postscript")
        end
        postscript = ""
    end

    return sep, postscript
end

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

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

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

]=]

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

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

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

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

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

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

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

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

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

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

This function sets an error message when |display-xxxxors= value greater than or equal to number of names but
not when <max> comes from {{cs1 config}} global settings.  When using global settings, <param> is set to the
keyword 'cs1 config' which is used to supress the normal error.  Error is suppressed because it is to be expected
that some citations in an article will have the same or fewer names that the limit specified in {{cs1 config}}.

]]
local function get_display_names(max, count, list_name, etal, param)
    if utilities.is_set(max) then
        if "etal" == max:lower():gsub("[ '%.]", "") then -- the :gsub() portion makes 'etal' from a variety of 'et al.' spellings and stylings
            max = count + 1 -- number of authors + 1 so display all author name plus et al.
            etal = true -- overrides value set by extract_names()
        elseif max:match("^%d+$") then -- if is a string of numbers
            max = tonumber(max) -- make it a number
            if (max >= count) and ("cs1 config" ~= param) then -- error when local |display-xxxxors= value greater than or equal to number of names; not an error when using global setting
                utilities.set_message("err_disp_name", {param, max}) -- add error message
                max = nil
            end
        else -- not a valid keyword or number
            utilities.set_message("err_disp_name", {param, max}) -- add error message
            max = nil -- unset; as if |display-xxxxors= had not been set
        end
    end

    return max, etal
end

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

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

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

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

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

Adds error if |volume= or |issue= has what appears to be some form of redundant 'type' indicator.  Applies to
both; this function looks for issue text in both |issue= and |volume= and looks for volume-like text in |voluem=
and |issue=.

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

For |issue=:
	'No.', 'I.', 'Iss.' (with or without the dot) abbreviations, or 'Issue' in the first characters of the
	parameter content (all case insensitive); numero styling: 'n°' with degree sign U+00B0, and № precomposed
	numero sign U+2116.
	
Single character values ('v', 'i', 'n') allowed when not followed by separator character ('.', ':', '=', or
whitespace character) – param values are trimmed of whitespace by MediaWiki before delivered to the module.
	
<val> is |volume= or |issue= parameter value
<name> is |volume= or |issue= parameter name for error message
<selector> is 'v' for |volume=, 'i' for |issue=

sets error message on failure; returns nothing

]]
local function extra_text_in_vol_iss_check(val, name, selector)
    if not utilities.is_set(val) then
        return
    end

    local handler = "v" == selector and "err_extra_text_volume" or "err_extra_text_issue"
    val = val:lower() -- force parameter value to lower case

    for _, pattern in ipairs(cfg.vol_iss_pg_patterns.vi_patterns_t) do -- spin through the sequence table of patterns
        if val:match(pattern) then -- when a match, error so
            utilities.set_message(handler, name) -- add error message
            return -- and done
        end
    end
end

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

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

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

]=]

local function get_v_name_table(vparam, output_table, output_link_table)
    local _, accept = utilities.has_accept_as_written(vparam)
    if accept then
        utilities.add_prop_cat("vanc-accept") -- add properties category
    end
    local name_table = mw.text.split(vparam, "%s*,%s*") -- names are separated by commas
    local wl_type, label, link  -- wl_type not used here; just a placeholder

    local i = 1

    while name_table[i] do
        if name_table[i]:match("^%(%(.*[^%)][^%)]$") then -- first segment of corporate with one or more commas; this segment has the opening doubled parentheses
            local name = name_table[i]
            i = i + 1 -- bump indexer to next segment
            while name_table[i] do
                name = name .. ", " .. name_table[i] -- concatenate with previous segments
                if name_table[i]:match("^.*%)%)$") then -- if this table member has the closing doubled parentheses
                    break -- and done reassembling so
                end
                i = i + 1 -- bump indexer
            end
            table.insert(output_table, name) -- and add corporate name to the output table
            table.insert(output_link_table, "") -- no wikilink
        else
            wl_type, label, link = utilities.is_wikilink(name_table[i]) -- wl_type is: 0, no wl (text in label variable); 1, [[D]]; 2, [[L|D]]
            table.insert(output_table, label) -- add this name
            if 1 == wl_type then
                table.insert(output_link_table, label) -- simple wikilink [[D]]
            else
                table.insert(output_link_table, link) -- no wikilink or [[L|D]]; add this link if there is one, else empty string
            end
        end
        i = i + 1
    end
    return output_table
end

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

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

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

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

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

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

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

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

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

            if not mw.ustring.match(first, "^%u+$") then -- mw.ustring here so that later we will catch non-Latin characters
                suffix = first -- not initials so assume that whatever we got is a generational suffix
                first = table.remove(lastfirstTable) -- get what should be the initials from the table
            end
            last = table.concat(lastfirstTable, " ") -- returns a string that is the concatenation of all other names that are not initials and generational suffix
            if not utilities.is_set(last) then
                first = "" -- unset
                last = v_name -- last empty because something wrong with first
                add_vanc_error(cfg.err_msg_supl.name, i)
            end
            if mw.ustring.match(last, "%a+%s+%u+%s+%a+") then
                add_vanc_error(cfg.err_msg_supl["missing comma"], i) -- matches last II last; the case when a comma is missing
            end
            if mw.ustring.match(v_name, " %u %u$") then -- this test is in the wrong place TODO: move or replace with a more appropriate test
                add_vanc_error(cfg.err_msg_supl.initials, i) -- matches a space between two initials
            end
        else
            last = v_name -- last name or single corporate name?  Doesn't support multiword corporate names? do we need this?
        end

        if utilities.is_set(first) then
            if not mw.ustring.match(first, "^%u?%u$") then -- first shall contain one or two upper-case letters, nothing else
                add_vanc_error(cfg.err_msg_supl.initials, i) -- too many initials; mixed case initials (which may be ok Romanization); hyphenated initials
            end
            is_good_vanc_name(last, first, suffix, i) -- check first and last before restoring the suffix which may have a non-Latin digit
            if utilities.is_set(suffix) then
                first = first .. " " .. suffix -- if there was a suffix concatenate with the initials
                suffix = "" -- unset so we don't add this suffix to all subsequent names
            end
        else
            if not corporate then
                is_good_vanc_name(last, "", nil, i)
            end
        end

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

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

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

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

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

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

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

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

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

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

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

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

TODO: explain <invert>

]]
local function is_valid_parameter_value(value, name, possible, ret_val, invert)
    if not utilities.is_set(value) then
        return ret_val -- an empty parameter is ok
    end

    if (not invert and utilities.in_array(value, possible)) then -- normal; <value> is in <possible> table
        return cfg.keywords_xlate[value] -- return translation of parameter keyword
    elseif invert and not utilities.in_array(value, possible) then -- invert; <value> is not in <possible> table
        return value -- return <value> as it is
    else
        utilities.set_message("err_invalid_param_val", {name, value}) -- not an allowed value so add error message
        return ret_val
    end
end

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

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

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

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

returns the concatenation of the formatted volume and issue (or journal article number) 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, article, cite_class, origin, sepc, lower)
    if not utilities.is_set(volume) and not utilities.is_set(issue) and not utilities.is_set(article) then
        return ""
    end

    -- same condition as in format_pages_sheets()
    local is_journal =
        "journal" == cite_class or
        (utilities.in_array(cite_class, {"citation", "map", "interview"}) and "journal" == origin)

    local is_numeric_vol = volume and (volume:match("^[MDCLXVI]+$") or volume:match("^%d+$")) -- is only uppercase roman numerals or only digits?
    local is_long_vol = volume and (4 < mw.ustring.len(volume)) -- is |volume= value longer than 4 characters?

    if volume and (not is_numeric_vol and is_long_vol) then -- when not all digits or Roman numerals, is |volume= longer than 4 characters?
        utilities.add_prop_cat("long-vol") -- yes, add properties cat
    end

    if is_journal then -- journal-style formatting
        local vol = ""

        if utilities.is_set(volume) then
            if is_numeric_vol then -- |volume= value all digits or all uppercase Roman numerals?
                vol = utilities.substitute(cfg.presentation["vol-bold"], {sepc, volume}) -- render in bold face
            elseif is_long_vol then -- not all digits or Roman numerals; longer than 4 characters?
                vol = utilities.substitute(cfg.messages["j-vol"], {sepc, utilities.hyphen_to_dash(volume)}) -- not bold
            else -- four or fewer characters
                vol = utilities.substitute(cfg.presentation["vol-bold"], {sepc, utilities.hyphen_to_dash(volume)}) -- bold
            end
        end
        vol = vol .. (utilities.is_set(issue) and utilities.substitute(cfg.messages["j-issue"], issue) or "")
        vol = vol .. (utilities.is_set(article) and utilities.substitute(cfg.messages["j-article-num"], article) or "")
        return vol
    end

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

    if "conference" == cite_class and utilities.is_set(article) then -- |article-number= supported only in journal and conference cites
        if utilities.is_set(volume) and utilities.is_set(article) then -- both volume and article number
            return wrap_msg("vol-art", {sepc, utilities.hyphen_to_dash(volume), article}, lower)
        elseif utilities.is_set(article) then -- article number alone; when volume alone, handled below
            return wrap_msg("art", {sepc, article}, lower)
        end
    end

    -- all other types of citation
    if utilities.is_set(volume) and utilities.is_set(issue) then
        return wrap_msg("vol-no", {sepc, utilities.hyphen_to_dash(volume), issue}, lower)
    elseif utilities.is_set(volume) then
        return wrap_msg("vol", {sepc, utilities.hyphen_to_dash(volume)}, lower)
    else
        return wrap_msg("issue", {sepc, issue}, lower)
    end
end

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

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

Singular has priority over plural when both are provided.

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

    local is_journal =
        "journal" == cite_class or
        (utilities.in_array(cite_class, {"citation", "map", "interview"}) and "journal" == origin)

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

    return "", "", "", "" -- return empty strings
end

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

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

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

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

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

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

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

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

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

    return page, pages, at, coins_pages
end

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

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

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

    return archive, date
end

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

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

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

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

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

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

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

A secondary function is to return an archive-url timestamp from those urls that have them (archive.org and
archive.today).  The timestamp is used by validation.archive_date_check() to see if the value in |archive-date=
matches the timestamp in the archive url.

]=]

local function archive_url_check(url, date)
    local err_msg = "" -- start with the error message empty
    local path, timestamp, flag  -- portions of the archive.org URL

    timestamp =
        url:match("//archive.today/(%d%d%d%d%d%d%d%d%d%d%d%d%d%d)/") or -- get timestamp from archive.today urls
        url:match("//archive.today/(%d%d%d%d%.%d%d%.%d%d%-%d%d%d%d%d%d)/") -- this timestamp needs cleanup
    if timestamp then -- if this was an archive.today url ...
        return url, date, timestamp:gsub("[%.%-]", "") -- return ArchiveURL, ArchiveDate, and timestamp (dots and dashes removed) from |archive-url=, and done
    end
    -- here for archive.org urls
    if (not url:match("//web%.archive%.org/")) and (not url:match("//liveweb%.archive%.org/")) then -- also deprecated liveweb Wayback machine URL
        return url, date -- not an archive.org archive, return ArchiveURL and ArchiveDate
    end

    if url:match("//web%.archive%.org/save/") then -- if a save command URL, we don't want to allow saving of the target page
        err_msg = cfg.err_msg_supl.save
        url = url:gsub("(//web%.archive%.org)/save/", "%1/*/", 1) -- for preview mode: modify ArchiveURL
    elseif url:match("//liveweb%.archive%.org/") then
        err_msg = cfg.err_msg_supl.liveweb
    else
        path, timestamp, flag = url:match("//web%.archive%.org/([^%d]*)(%d+)([^/]*)/") -- split out some of the URL parts for evaluation
        if not path then -- malformed in some way; pattern did not match
            err_msg = cfg.err_msg_supl.timestamp
        elseif 14 ~= timestamp:len() then -- path and flag optional, must have 14-digit timestamp here
            err_msg = cfg.err_msg_supl.timestamp
            if "*" ~= flag then
                local replacement = timestamp:match("^%d%d%d%d%d%d") or timestamp:match("^%d%d%d%d") -- get the first 6 (YYYYMM) or first 4 digits (YYYY)
                if replacement then -- nil if there aren't at least 4 digits (year)
                    replacement = replacement .. string.rep("0", 14 - replacement:len()) -- year or yearmo (4 or 6 digits) zero-fill to make 14-digit timestamp
                    url = url:gsub("(//web%.archive%.org/[^%d]*)%d[^/]*", "%1" .. replacement .. "*", 1) -- for preview, modify ts to 14 digits plus splat for calendar display
                end
            end
        elseif utilities.is_set(path) and "web/" ~= path then -- older archive URLs do not have the extra 'web/' path element
            err_msg = cfg.err_msg_supl.path
        elseif utilities.is_set(flag) and not utilities.is_set(path) then -- flag not allowed with the old form URL (without the 'web/' path element)
            err_msg = cfg.err_msg_supl.flag
        elseif utilities.is_set(flag) and not flag:match("%a%a_") then -- flag if present must be two alpha characters and underscore (requires 'web/' path element)
            err_msg = cfg.err_msg_supl.flag
        else
            return url, date, timestamp -- return ArchiveURL, ArchiveDate, and timestamp from |archive-url=
        end
    end
    -- if here, something not right so
    utilities.set_message("err_archive_url", {err_msg}) -- add error message and

    if is_preview_mode then
        return url, date, timestamp -- preview mode so return ArchiveURL, ArchiveDate, and timestamp from |archive-url=
    else
        return "", "" -- return empty strings for ArchiveURL and ArchiveDate
    end
end

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

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

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

]]
local function place_check(param_val)
    if not utilities.is_set(param_val) then -- parameter empty or omitted
        return param_val -- return that empty state
    end

    if mw.ustring.find(param_val, "%d") then -- not empty, are there digits in the parameter value
        utilities.set_message("maint_location") -- yep, add maint cat
    end

    return param_val -- and done
end

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

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

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

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

for any of the |display-authors=, |display-editors=, etc parameters, select either the local or global setting.
When both are present, look at <local_display_names> value.  When the value is some sort of 'et al.'string,
special handling is required.

When {{cs1 config}} has |display-<namelist>= AND this template has |display-<namelist>=etal AND:
	the number of names specified by <number_of_names> is:
		greater than the number specified in the global |display-<namelist>= parameter (<global_display_names>)
			use global |display-<namelist>= parameter value
			set overridden maint category
		less than or equal to the number specified in the global |display-<namelist>=  parameter
			use local |display-<namelist>= parameter value

The purpose of this function is to prevent categorizing a template that has fewer names than the global setting
to keep the etal annotation specified by <local_display_names>.

]]
local function display_names_select(global_display_names, local_display_names, param_name, number_of_names, test)
    if global_display_names and utilities.is_set(local_display_names) then -- when both
        if "etal" == local_display_names:lower():gsub("[ '%.]", "") then -- the :gsub() portion makes 'etal' from a variety of 'et al.' spellings and stylings
            number_of_names = tonumber(number_of_names) -- convert these to numbers for comparison
            local global_display_names_num = tonumber(global_display_names) -- <global_display_names> not set when parameter value is not digits

            if number_of_names > global_display_names_num then -- template has more names than global config allows to be displayed?
                utilities.set_message("maint_overridden_setting") -- set a maint message because global is overriding local |display-<namelist>=etal
                return global_display_names, "cs1 config" -- return global with spoof parameter name (for get_display_names())
            else
                return local_display_names, param_name -- return local because fewer names so let <local_display_names> control
            end
        end
        -- here when <global_display_names> and <local_display_names> both numbers; <global_display_names> controls
        utilities.set_message("maint_overridden_setting") -- set a maint message
        return global_display_names, "cs1 config" -- return global with spoof parameter name (for get_display_names())
    end
    -- here when only one of <global_display_names> or <local_display_names> set
    if global_display_names then
        return global_display_names, "cs1 config" -- return global with spoof parameter name (for get_display_names())
    else
        return local_display_names, param_name -- return local
    end
end

--[[--------------------------< M O D E _ S E T >--------------------------------------------------------------

fetch global mode setting from {{cs1 config}} (if present) or from |mode= (if present); global setting overrides
local |mode= parameter value.  When both are present, emit maintenance message

]]
local function mode_set(Mode, Mode_origin)
    local mode
    if cfg.global_cs1_config_t["Mode"] then -- global setting in {{cs1 config}}; nil when empty or assigned value invalid
        mode =
            is_valid_parameter_value(
            cfg.global_cs1_config_t["Mode"],
            "cs1 config: mode",
            cfg.keywords_lists["mode"],
            ""
        ) -- error messaging 'param' here is a hoax
    else
        mode = is_valid_parameter_value(Mode, Mode_origin, cfg.keywords_lists["mode"], "")
    end

    if cfg.global_cs1_config_t["Mode"] and utilities.is_set(Mode) then -- when template has |mode=<something> which global setting has overridden
        utilities.set_message("maint_overridden_setting") -- set a maint message
    end
    return mode
end

--[[--------------------------< Q U O T E _ M A K E >----------------------------------------------------------

create quotation from |quote=, |trans-quote=, and/or script-quote= with or without |quote-page= or |quote-pages=

when any of those three quote parameters are set, this function unsets <PostScript>.  When none of those parameters
are set, |quote-page= and |quote-pages= are unset to nil so that they are not included in the template's metadata

]]
local function quote_make(quote, trans_quote, script_quote, quote_page, quote_pages, nopp, sepc, postscript)
    if utilities.is_set(quote) or utilities.is_set(trans_quote) or utilities.is_set(script_quote) then
        if utilities.is_set(quote) then
            if quote:sub(1, 1) == '"' and quote:sub(-1, -1) == '"' then -- if first and last characters of quote are quote marks
                quote = quote:sub(2, -2) -- strip them off
            end
        end

        quote = kern_quotes(quote) -- kern if needed
        quote = utilities.wrap_style("quoted-text", quote) -- wrap in <q>...</q> tags

        if utilities.is_set(script_quote) then
            quote = script_concatenate(quote, script_quote, "script-quote") -- <bdi> tags, lang attribute, categorization, etc.; must be done after quote is wrapped
        end

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

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

            quote = quote_prefix .. ": " .. quote
        else
            quote = sepc .. " " .. quote
        end

        postscript = "" -- cs1|2 does not supply terminal punctuation when |quote= is set
    elseif utilities.is_set(quote_page) or utilities.is_set(quote_pages) then
        quote_page = nil -- unset; these require |quote=; TODO: error message?
        quote_pages = nil
    end

    return quote, quote_page, quote_pages, postscript
end

--[[--------------------------< C H E C K _ P U B L I S H E R _ N A M E >--------------------------------------

look for variations of '<text>: <text>' that might be '<location>: <publisher>' in |publisher= parameter value.
when found, emit a maintenance message; return nil else

<publisher> is the value assigned to |publisher= or |institution=

]]
local function check_publisher_name(publisher)
    local patterns_t = {
        "^[%w%s]+%s*:%s*[%w%s]+$", -- plain text <location>: <publisher>
        "^%[+[%w%s:|]+%]+%s*:%s*[%w%s]+$", -- partially wikilinked [[<location>]]: <publisher>
        "^[%w%s]+%s*:%s*%[+[%w%s:|]+%]+$", -- partially wikilinked <location>: [[<publisher>]]
        "^%[+[%w%s:|]+%]+%s*:%s*%[+[%w%s:|]+%]+$" -- wikilinked [[<location>]]: [[<publisher>]]
    }

    for _, pattern in ipairs(patterns_t) do -- spin through the patterns_t sequence
        if mw.ustring.match(publisher, pattern) then -- does this pattern match?
            utilities.set_message("maint_publisher_location") -- set a maint message
            return -- and done
        end
    end
end

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

compare the trailing (rightmost) characters of the |doi= value against the whole value assigned to |page(s)=.

return boolean true when:
	|page(s)= has exactly 8 digits and a dot between the fourth and fifth digits matches the trailing 9 characters
		of the |doi= value: |page=12345678 → |page=1234.5678 matches |doi=10.xxxx/yyyy1234.5678
	|page(s)= is 5 or more characters and matches |doi= values's trailing characters
	|page(s)= begins with a lowercase 'e' and |page(s)= without the 'e' matches |doi= values's trailing
		characters: |page=e12345 → |page=12345 matches |doi=10.xxxx/yyyy12345
	|page(s)= begins with a uppercase 'CD' followed by (typically) six digits matches |doi= values that ends with
		'CDxxxxxx.pubx' (where 'x' is any single digit)

return nil when |page(s)= values:
	are ranges separated by underscore, hyphen, emdash, endash, figure dash, or minus character
	are comma- or semicolon-separated lists of pages
	have external urls (has text 'http')
	are digit-only values less than 10000
	do not match |doi= values's trailing characters

]]
local function is_page_art_num(page, doi)
    if not (utilities.is_set(page) and utilities.is_set(doi)) then -- both required
        return -- abandon; nothing to do
    end

    if page:match("[,;_−–—‒%-]") then -- when |page(s)= might be a page range or a separated list of pages
        return -- abandon
    end

    page = page:lower() -- because doi names are case insensitive
    doi = doi:lower() -- force these to lowercase for testing

    if page:match("http") then -- when |page(s)= appears to hold a url
        return -- abandon
    end

    if tonumber(page) then -- is |page(s)= digits only
        if 10000 > tonumber(page) then -- when |page(s)= less than 10000
            return -- abandon
        end

        if doi:match(page .. "$") then -- digits only page number match the last digits in |doi=?
            return true
        end

        if 8 == page:len() then -- special case when |page(s)= is exactly 8 digits
            local dot_page = page:gsub("(%d%d%d%d)(%d%d%d%d)", "%1.%2") -- make a |page=xxxx.yyyy version commonly used in |doi=
            if doi:match(dot_page .. "$") then -- 8-digit dotted page number match the last characters in |doi=?
                return true
            end
        end
    else -- here when |page(s)= is alpha-numeric
        if 4 < page:len() then -- when |page(s)= is five or more characters
            if doi:match(page .. "$") then -- alpha-numeric page match the last characters in |doi=?
                return true
            end

            local epage = page:match("^e([%w]+)$") -- if first character of |page= is 'e', remove it
            if epage and doi:match(epage .. "$") then -- page number match the last characters in |doi=?
                return true
            end

            local cdpage = page:match("^cd%d+$") -- if first characters of |page= are 'CD' and last characters are digits (typically 6 digits)
            if cdpage and doi:match(cdpage .. "%.pub%d$") then -- page number matches doi 'CDxxxxxx.pubx' where 'x' is a digit
                return true
            end
        end
    end
end

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

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

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

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

    local author_etal
    local a = {} -- authors list from |lastn= / |firstn= pairs or |vauthors=
    local Authors
    local NameListStyle
    if cfg.global_cs1_config_t["NameListStyle"] then -- global setting in {{cs1 config}} overrides local |name-list-style= parameter value; nil when empty or assigned value invalid
        NameListStyle =
            is_valid_parameter_value(
            cfg.global_cs1_config_t["NameListStyle"],
            "cs1 config: name-list-style",
            cfg.keywords_lists["name-list-style"],
            ""
        ) -- error messaging 'param' here is a hoax
    else
        NameListStyle =
            is_valid_parameter_value(
            A["NameListStyle"],
            A:ORIGIN("NameListStyle"),
            cfg.keywords_lists["name-list-style"],
            ""
        )
    end

    if cfg.global_cs1_config_t["NameListStyle"] and utilities.is_set(A["NameListStyle"]) then -- when template has |name-list-style=<something> which global setting has overridden
        utilities.set_message("maint_overridden_setting") -- set a maint message
    end

    local Collaboration = A["Collaboration"]

    do -- to limit scope of selected
        local selected = select_author_editor_source(A["Vauthors"], A["Authors"], args, "AuthorList")
        if 1 == selected then
            a, author_etal = extract_names(args, "AuthorList") -- fetch author list from |authorn= / |lastn= / |firstn=, |author-linkn=, and |author-maskn=
        elseif 2 == selected then
            NameListStyle = "vanc" -- override whatever |name-list-style= might be
            a, author_etal = parse_vauthors_veditors(args, A["Vauthors"], "AuthorList") -- fetch author list from |vauthors=, |author-linkn=, and |author-maskn=
        elseif 3 == selected then
            Authors = A["Authors"] -- use content of |people= or |credits=; |authors= is deprecated; TODO: constrain |people= and |credits= to cite av media, episode, serial?
        end
        if utilities.is_set(Collaboration) then
            author_etal = true -- so that |display-authors=etal not required
        end
    end

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

    do -- to limit scope of selected
        local selected = select_author_editor_source(A["Veditors"], nil, args, "EditorList") -- support for |editors= withdrawn
        if 1 == selected then
            e, editor_etal = extract_names(args, "EditorList") -- fetch editor list from |editorn= / |editor-lastn= / |editor-firstn=, |editor-linkn=, and |editor-maskn=
        elseif 2 == selected then
            NameListStyle = "vanc" -- override whatever |name-list-style= might be
            e, editor_etal = parse_vauthors_veditors(args, args.veditors, "EditorList") -- fetch editor list from |veditors=, |editor-linkn=, and |editor-maskn=
        end
    end

    local Chapter = A["Chapter"] -- done here so that we have access to |contribution= from |chapter= aliases
    local Chapter_origin = A:ORIGIN("Chapter")
    local Contribution  -- because contribution is required for contributor(s)
    if "contribution" == Chapter_origin then
        Contribution = Chapter -- get the name of the contribution
    end
    local c = {} -- contributors list from |contributor-lastn= / contributor-firstn= pairs

    if utilities.in_array(config.CitationClass, {"book", "citation"}) and not utilities.is_set(A["Periodical"]) then -- |contributor= and |contribution= only supported in book cites
        c = extract_names(args, "ContributorList") -- fetch contributor list from |contributorn= / |contributor-lastn=, -firstn=, -linkn=, -maskn=

        if 0 < #c then
            if not utilities.is_set(Contribution) then -- |contributor= requires |contribution=
                utilities.set_message("err_contributor_missing_required_param", "contribution") -- add missing contribution error message
                c = {} -- blank the contributors' table; it is used as a flag later
            end
            if 0 == #a then -- |contributor= requires |author=
                utilities.set_message("err_contributor_missing_required_param", "author") -- add missing author error message
                c = {} -- blank the contributors' table; it is used as a flag later
            end
        end
    else -- if not a book cite
        if utilities.select_one(args, cfg.aliases["ContributorList-Last"], "err_redundant_parameters", 1) then -- are there contributor name list parameters?
            utilities.set_message("err_contributor_ignored") -- add contributor ignored error message
        end
        Contribution = nil -- unset
    end

    local Title = A["Title"]
    local TitleLink = A["TitleLink"]

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

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

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

    local Periodical = A["Periodical"]
    local Periodical_origin = A:ORIGIN("Periodical")
    local ScriptPeriodical = A["ScriptPeriodical"]
    local ScriptPeriodical_origin = A:ORIGIN("ScriptPeriodical")
    local TransPeriodical = A["TransPeriodical"]
    local TransPeriodical_origin = A:ORIGIN("TransPeriodical")

    if
        (utilities.in_array(config.CitationClass, {"book", "encyclopaedia"}) and
            (utilities.is_set(Periodical) or utilities.is_set(ScriptPeriodical) or utilities.is_set(TransPeriodical)))
     then
        local param
        if utilities.is_set(Periodical) then -- get a parameter name from one of these periodical related meta-parameters
            Periodical = "" -- unset because not valid {{cite book}} or {{cite encyclopedia}} parameters
            param = Periodical_origin -- get parameter name for error messaging
        elseif utilities.is_set(TransPeriodical) then
            TransPeriodical = "" -- unset because not valid {{cite book}} or {{cite encyclopedia}} parameters
            param = TransPeriodical_origin -- get parameter name for error messaging
        elseif utilities.is_set(ScriptPeriodical) then
            ScriptPeriodical = "" -- unset because not valid {{cite book}} or {{cite encyclopedia}} parameters
            param = ScriptPeriodical_origin -- get parameter name for error messaging
        end

        if utilities.is_set(param) then -- if we found one
            utilities.set_message("err_periodical_ignored", {param}) -- emit an error message
        end
    end

    if utilities.is_set(Periodical) then
        local i
        Periodical, i = utilities.strip_apostrophe_markup(Periodical) -- strip apostrophe markup so that metadata isn't contaminated
        if i then -- non-zero when markup was stripped so emit an error message
            utilities.set_message("err_apostrophe_markup", {Periodical_origin})
        end
    end

    if "mailinglist" == config.CitationClass then -- special case for {{cite mailing list}}
        if utilities.is_set(Periodical) and utilities.is_set(A["MailingList"]) then -- both set emit an error TODO: make a function for this and similar?
            utilities.set_message(
                "err_redundant_parameters",
                {
                    utilities.wrap_style("parameter", Periodical_origin) ..
                        cfg.presentation["sep_list_pair"] .. utilities.wrap_style("parameter", "mailinglist")
                }
            )
        end

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

    -- web and news not tested for now because of
    -- Wikipedia:Administrators%27_noticeboard#Is_there_a_semi-automated_tool_that_could_fix_these_annoying_"Cite_Web"_errors?
    if not (utilities.is_set(Periodical) or utilities.is_set(ScriptPeriodical)) then -- 'periodical' templates require periodical parameter
        --	local p = {['journal'] = 'journal', ['magazine'] = 'magazine', ['news'] = 'newspaper', ['web'] = 'website'};	-- for error message
        local p = {["journal"] = "journal", ["magazine"] = "magazine"} -- for error message
        if p[config.CitationClass] then
            utilities.set_message("err_missing_periodical", {config.CitationClass, p[config.CitationClass]})
        end
    end

    local Volume
    if "citation" == config.CitationClass then
        if utilities.is_set(Periodical) then
            if not utilities.in_array(Periodical_origin, cfg.citation_no_volume_t) then -- {{citation}} does not render |volume= when these parameters are used
                Volume = A["Volume"] -- but does for all other 'periodicals'
            end
        elseif utilities.is_set(ScriptPeriodical) then
            if "script-website" ~= ScriptPeriodical_origin then -- {{citation}} does not render volume for |script-website=
                Volume = A["Volume"] -- but does for all other 'periodicals'
            end
        else
            Volume = A["Volume"] -- and does for non-'periodical' cites
        end
    elseif utilities.in_array(config.CitationClass, cfg.templates_using_volume) then -- render |volume= for cs1 according to the configuration settings
        Volume = A["Volume"]
    end
    extra_text_in_vol_iss_check(Volume, A:ORIGIN("Volume"), "v")

    local Issue
    if "citation" == config.CitationClass then
        if utilities.is_set(Periodical) and utilities.in_array(Periodical_origin, cfg.citation_issue_t) then -- {{citation}} may render |issue= when these parameters are used
            Issue = utilities.hyphen_to_dash(A["Issue"])
        end
    elseif utilities.in_array(config.CitationClass, cfg.templates_using_issue) then -- conference & map books do not support issue; {{citation}} listed here because included in settings table
        if
            not (utilities.in_array(config.CitationClass, {"conference", "map", "citation"}) and
                not (utilities.is_set(Periodical) or utilities.is_set(ScriptPeriodical)))
         then
            Issue = utilities.hyphen_to_dash(A["Issue"])
        end
    end

    local ArticleNumber

    if
        utilities.in_array(config.CitationClass, {"journal", "conference"}) or
            ("citation" == config.CitationClass and utilities.is_set(Periodical) and "journal" == Periodical_origin)
     then
        ArticleNumber = A["ArticleNumber"]
    end

    extra_text_in_vol_iss_check(Issue, A:ORIGIN("Issue"), "i")

    local Page
    local Pages
    local At
    local QuotePage
    local QuotePages
    if not utilities.in_array(config.CitationClass, cfg.templates_not_using_page) then -- TODO: rewrite to emit ignored parameter error message?
        Page = A["Page"]
        Pages = utilities.hyphen_to_dash(A["Pages"])
        At = A["At"]
        QuotePage = A["QuotePage"]
        QuotePages = utilities.hyphen_to_dash(A["QuotePages"])
    end

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

    local Mode = mode_set(A["Mode"], A:ORIGIN("Mode"))

    -- separator character and postscript
    local sepc, PostScript = set_style(Mode:lower(), A["PostScript"], config.CitationClass)
    local Quote
    Quote, QuotePage, QuotePages, PostScript =
        quote_make(A["Quote"], A["TransQuote"], A["ScriptQuote"], QuotePage, QuotePages, NoPP, sepc, PostScript)

    local Edition = A["Edition"]
    local PublicationPlace = place_check(A["PublicationPlace"], A:ORIGIN("PublicationPlace"))
    local Place = place_check(A["Place"], A:ORIGIN("Place"))

    local PublisherName = A["PublisherName"]
    local PublisherName_origin = A:ORIGIN("PublisherName")
    if utilities.is_set(PublisherName) and (cfg.keywords_xlate["none"] ~= PublisherName) then
        local i = 0
        PublisherName, i = utilities.strip_apostrophe_markup(PublisherName) -- strip apostrophe markup so that metadata isn't contaminated; publisher is never italicized
        if i and (0 < i) then -- non-zero when markup was stripped so emit an error message
            utilities.set_message("err_apostrophe_markup", {PublisherName_origin})
        end
    end

    if ("document" == config.CitationClass) and not utilities.is_set(PublisherName) then
        utilities.set_message("err_missing_publisher", {config.CitationClass, "publisher"})
    end

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

    if "newsgroup" == config.CitationClass then
        if utilities.is_set(PublisherName) and (cfg.keywords_xlate["none"] ~= PublisherName) then -- general use parameter |publisher= not allowed in cite newsgroup
            utilities.set_message("err_parameter_ignored", {PublisherName_origin})
        end

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

    if
        "book" == config.CitationClass or "encyclopaedia" == config.CitationClass or
            ("citation" == config.CitationClass and not utilities.is_set(Periodical))
     then
        local accept
        PublisherName, accept = utilities.has_accept_as_written(PublisherName) -- check for and remove accept-as-written markup from |publisher= wrapped
        if not accept then -- when no accept-as-written markup
            check_publisher_name(PublisherName) -- emit maint message when |publisher= might be prefixed with publisher's location
        end
    end

    local URL = A["URL"] -- TODO: better way to do this for URL, ChapterURL, and MapURL?
    local UrlAccess =
        is_valid_parameter_value(A["UrlAccess"], A:ORIGIN("UrlAccess"), cfg.keywords_lists["url-access"], nil)

    if not utilities.is_set(URL) and utilities.is_set(UrlAccess) then
        UrlAccess = nil
        utilities.set_message("err_param_access_requires_param", "url")
    end

    local ChapterURL = A["ChapterURL"]
    local ChapterUrlAccess =
        is_valid_parameter_value(
        A["ChapterUrlAccess"],
        A:ORIGIN("ChapterUrlAccess"),
        cfg.keywords_lists["url-access"],
        nil
    )
    if not utilities.is_set(ChapterURL) and utilities.is_set(ChapterUrlAccess) then
        ChapterUrlAccess = nil
        utilities.set_message("err_param_access_requires_param", {A:ORIGIN("ChapterUrlAccess"):gsub("%-access", "")})
    end

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

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

    -- check this page to see if it is in one of the namespaces that cs1 is not supposed to add to the error categories
    if not utilities.is_set(no_tracking_cats) then -- ignore if we are already not going to categorize this page
        if cfg.uncategorized_namespaces[this_page.namespace] then -- is this page's namespace id one of the uncategorized namespace ids?
            no_tracking_cats = "true" -- set no_tracking_cats
        end
        for _, v in ipairs(cfg.uncategorized_subpages) do -- cycle through page name patterns
            if this_page.text:match(v) then -- test page name against each pattern
                no_tracking_cats = "true" -- set no_tracking_cats
                break -- bail out if one is found
            end
        end
    end
    -- check for extra |page=, |pages= or |at= parameters. (also sheet and sheets while we're at it)
    utilities.select_one(args, {"page", "p", "pp", "pages", "at", "sheet", "sheets"}, "err_redundant_parameters") -- this is a dummy call simply to get the error message and category

    local coins_pages

    Page, Pages, At, coins_pages = insource_loc_get(Page, A:ORIGIN("Page"), Pages, A:ORIGIN("Pages"), At)

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

    if PublicationPlace == Place then
        Place = ""
    end -- don't need both if they are the same

    local URL_origin = A:ORIGIN("URL") -- get name of parameter that holds URL
    local ChapterURL_origin = A:ORIGIN("ChapterURL") -- get name of parameter that holds ChapterURL
    local ScriptChapter = A["ScriptChapter"]
    local ScriptChapter_origin = A:ORIGIN("ScriptChapter")
    local Format = A["Format"]
    local ChapterFormat = A["ChapterFormat"]
    local TransChapter = A["TransChapter"]
    local TransChapter_origin = A:ORIGIN("TransChapter")
    local TransTitle = A["TransTitle"]
    local ScriptTitle = A["ScriptTitle"]

    --[[
	Parameter remapping for cite encyclopedia:
	When the citation has these parameters:
		|encyclopedia= and |title= then map |title= to |article= and |encyclopedia= to |title= for rendering
		|encyclopedia= and |article= then map |encyclopedia= to |title= for rendering

		|trans-title= maps to |trans-chapter= when |title= is re-mapped
		|url= maps to |chapter-url= when |title= is remapped
	
	All other combinations of |encyclopedia=, |title=, and |article= are not modified
	
	]]
    local Encyclopedia = A["Encyclopedia"] -- used as a flag by this module and by ~/COinS
    local ScriptEncyclopedia = A["ScriptEncyclopedia"]
    local TransEncyclopedia = A["TransEncyclopedia"]

    if utilities.is_set(Encyclopedia) or utilities.is_set(ScriptEncyclopedia) then -- emit error message when Encyclopedia set but template is other than {{cite encyclopedia}} or {{citation}}
        if "encyclopaedia" ~= config.CitationClass and "citation" ~= config.CitationClass then
            if utilities.is_set(Encyclopedia) then
                utilities.set_message("err_parameter_ignored", {A:ORIGIN("Encyclopedia")})
            else
                utilities.set_message("err_parameter_ignored", {A:ORIGIN("ScriptEncyclopedia")})
            end
            Encyclopedia = nil -- unset these because not supported by this template
            ScriptEncyclopedia = nil
            TransEncyclopedia = nil
        end
    elseif utilities.is_set(TransEncyclopedia) then
        utilities.set_message("err_trans_missing_title", {"encyclopedia"})
    end

    if
        ("encyclopaedia" == config.CitationClass) or
            ("citation" == config.CitationClass and utilities.is_set(Encyclopedia))
     then
        if utilities.is_set(Periodical) and utilities.is_set(Encyclopedia) then -- when both parameters set emit an error message; {{citation}} only; Periodical not allowed in {{cite encyclopedia}}
            utilities.set_message("err_periodical_ignored", {Periodical_origin})
        end

        if utilities.is_set(Encyclopedia) or utilities.is_set(ScriptEncyclopedia) then
            Periodical = Encyclopedia -- error or no, set Periodical to Encyclopedia for rendering; {{citation}} could (not legitimately) have both; use Encyclopedia
            Periodical_origin = A:ORIGIN("Encyclopedia")
            ScriptPeriodical = ScriptEncyclopedia
            ScriptPeriodical_origin = A:ORIGIN("ScriptEncyclopedia")

            if utilities.is_set(Title) or utilities.is_set(ScriptTitle) then
                if not utilities.is_set(Chapter) then
                    Chapter = Title -- |encyclopedia= and |title= are set so map |title= params to |article= params for rendering
                    ScriptChapter = ScriptTitle
                    ScriptChapter_origin = A:ORIGIN("ScriptTitle")
                    TransChapter = TransTitle
                    ChapterURL = URL
                    ChapterURL_origin = URL_origin
                    ChapterUrlAccess = UrlAccess
                    ChapterFormat = Format

                    if not utilities.is_set(ChapterURL) and utilities.is_set(TitleLink) then
                        Chapter = utilities.make_wikilink(TitleLink, Chapter)
                    end
                    Title = Periodical -- now map |encyclopedia= params to |title= params for rendering
                    ScriptTitle = ScriptPeriodical or ""
                    TransTitle = TransEncyclopedia or ""
                    Periodical = "" -- redundant so unset
                    ScriptPeriodical = ""
                    URL = ""
                    Format = ""
                    TitleLink = ""
                end
            elseif utilities.is_set(Chapter) or utilities.is_set(ScriptChapter) then -- |title= not set
                Title = Periodical -- |encyclopedia= set and |article= set so map |encyclopedia= to |title= for rendering
                ScriptTitle = ScriptPeriodical or ""
                TransTitle = TransEncyclopedia or ""
                Periodical = "" -- redundant so unset
                ScriptPeriodical = ""
            end
        end
    end

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

    -- Account for the oddity that is {{cite conference}}, before generation of COinS data.
    local ChapterLink  -- = A['ChapterLink'];									-- deprecated as a parameter but still used internally by cite episode
    local Conference = A["Conference"]
    local BookTitle = A["BookTitle"]
    local TransTitle_origin = A:ORIGIN("TransTitle")
    if "conference" == config.CitationClass then
        if utilities.is_set(BookTitle) then
            Chapter = Title
            Chapter_origin = "title"
            --		ChapterLink = TitleLink;											-- |chapter-link= is deprecated
            ChapterURL = URL
            ChapterUrlAccess = UrlAccess
            ChapterURL_origin = URL_origin
            URL_origin = ""
            ChapterFormat = Format
            TransChapter = TransTitle
            TransChapter_origin = TransTitle_origin
            Title = BookTitle
            Format = ""
            --		TitleLink = '';
            TransTitle = ""
            URL = ""
        end
    elseif "speech" ~= config.CitationClass then
        Conference = "" -- not cite conference or cite speech so make sure this is empty string
    end

    local use_lowercase = (sepc == ",") -- controls capitalization of certain static text

    -- cite map oddities
    local Cartography = ""
    local Scale = ""
    local Sheet = A["Sheet"] or ""
    local Sheets = A["Sheets"] or ""
    if config.CitationClass == "map" then
        if utilities.is_set(Chapter) then --TODO: make a function for this and similar?
            utilities.set_message(
                "err_redundant_parameters",
                {
                    utilities.wrap_style("parameter", "map") ..
                        cfg.presentation["sep_list_pair"] .. utilities.wrap_style("parameter", Chapter_origin)
                }
            ) -- add error message
        end
        Chapter = A["Map"]
        Chapter_origin = A:ORIGIN("Map")
        ChapterURL = A["MapURL"]
        ChapterURL_origin = A:ORIGIN("MapURL")
        TransChapter = A["TransMap"]
        ScriptChapter = A["ScriptMap"]
        ScriptChapter_origin = A:ORIGIN("ScriptMap")

        ChapterUrlAccess = MapUrlAccess
        ChapterFormat = A["MapFormat"]

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

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

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

        local Network = A["Network"]
        local Station = A["Station"]
        local s, n = {}, {}
        -- do common parameters first
        if utilities.is_set(Network) then
            table.insert(n, Network)
        end
        if utilities.is_set(Station) then
            table.insert(n, Station)
        end
        ID = table.concat(n, sepc .. " ")

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

            if utilities.is_set(Season) and utilities.is_set(SeriesNumber) then -- these are mutually exclusive so if both are set TODO: make a function for this and similar?
                utilities.set_message(
                    "err_redundant_parameters",
                    {
                        utilities.wrap_style("parameter", "season") ..
                            cfg.presentation["sep_list_pair"] .. utilities.wrap_style("parameter", "seriesno")
                    }
                ) -- add error message
                SeriesNumber = "" -- unset; prefer |season= over |seriesno=
            end
            -- assemble a table of parts concatenated later into Series
            if utilities.is_set(Season) then
                table.insert(s, wrap_msg("season", Season, use_lowercase))
            end
            if utilities.is_set(SeriesNumber) then
                table.insert(s, wrap_msg("seriesnum", SeriesNumber, use_lowercase))
            end
            if utilities.is_set(Issue) then
                table.insert(s, wrap_msg("episode", Issue, use_lowercase))
            end
            Issue = "" -- unset because this is not a unique parameter

            Chapter = Title -- promote title parameters to chapter
            ScriptChapter = ScriptTitle
            ScriptChapter_origin = A:ORIGIN("ScriptTitle")
            ChapterLink = TitleLink -- alias |episode-link=
            TransChapter = TransTitle
            ChapterURL = URL
            ChapterUrlAccess = UrlAccess
            ChapterURL_origin = URL_origin
            ChapterFormat = Format

            Title = Series -- promote series to title
            TitleLink = SeriesLink
            Series = table.concat(s, sepc .. " ") -- this is concatenation of season, seriesno, episode number

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

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

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

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

    if utilities.is_set(Year) then
        validation.year_check(Year) -- returns nothing; emits maint message when |year= doesn't hold a 'year' value
    end

    if not utilities.is_set(Date) then
        Date = Year -- promote Year to Date
        Year = nil -- make nil so Year as empty string isn't used for CITEREF
        if not utilities.is_set(Date) and utilities.is_set(PublicationDate) then -- use PublicationDate when |date= and |year= are not set
            Date = PublicationDate -- promote PublicationDate to Date
            PublicationDate = "" -- unset, no longer needed
            Date_origin = A:ORIGIN("PublicationDate") -- save the name of the promoted parameter
        else
            Date_origin = A:ORIGIN("Year") -- save the name of the promoted parameter
        end
    else
        Date_origin = A:ORIGIN("Date") -- not a promotion; name required for error messaging
    end

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

    --[[
	Go test all of the date-holding parameters for valid MOS:DATE format and make sure that dates are real dates. This must be done before we do COinS because here is where
	we get the date used in the metadata.
	
	Date validation supporting code is in Module:Citation/CS1/Date_validation
	]]
    local DF = is_valid_parameter_value(A["DF"], A:ORIGIN("DF"), cfg.keywords_lists["df"], "")
    if not utilities.is_set(DF) then
        DF = cfg.global_df -- local |df= if present overrides global df set by {{use xxx date}} template
    end

    local ArchiveURL
    local ArchiveDate
    local ArchiveFormat = A["ArchiveFormat"]
    local archive_url_timestamp  -- timestamp from wayback machine url

    ArchiveURL, ArchiveDate, archive_url_timestamp = archive_url_check(A["ArchiveURL"], A["ArchiveDate"])
    ArchiveFormat = style_format(ArchiveFormat, ArchiveURL, "archive-format", "archive-url")

    ArchiveURL, ArchiveDate = is_unique_archive_url(ArchiveURL, URL, ChapterURL, A:ORIGIN("ArchiveURL"), ArchiveDate) -- add error message when URL or ChapterURL == ArchiveURL

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

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

        if utilities.is_set(Year) and utilities.is_set(Date) then -- both |date= and |year= not normally needed;
            validation.year_date_check(Year, A:ORIGIN("Year"), Date, A:ORIGIN("Date"), error_list)
        end

        if 0 == #error_list then -- error free dates only; 0 when error_list is empty
            local modified = false -- flag

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

            if true == validation.date_hyphen_to_dash(date_parameters_list) then -- convert hyphens to dashes where appropriate
                modified = true
                utilities.set_message("maint_date_format") -- hyphens were converted so add maint category
            end

            -- for those wikis that can and want to have English date names translated to the local language; not supported at en.wiki
            if
                cfg.date_name_auto_xlate_enable and
                    validation.date_name_xlate(date_parameters_list, cfg.date_digit_auto_xlate_enable)
             then
                utilities.set_message("maint_date_auto_xlated") -- add maint cat
                modified = true
            end

            if modified then -- if the date_parameters_list values were modified
                AccessDate = date_parameters_list["access-date"].val -- overwrite date holding parameters with modified values
                ArchiveDate = date_parameters_list["archive-date"].val
                Date = date_parameters_list["date"].val
                DoiBroken = date_parameters_list["doi-broken-date"].val
                PublicationDate = date_parameters_list["publication-date"].val
            end

            if archive_url_timestamp and utilities.is_set(ArchiveDate) then
                validation.archive_date_check(ArchiveDate, archive_url_timestamp, DF) -- does YYYYMMDD in archive_url_timestamp match date in ArchiveDate
            end
        else
            utilities.set_message("err_bad_date", {utilities.make_sep_list(#error_list, error_list)}) -- add this error message
        end
    end -- end of do

    if
        utilities.in_array(config.CitationClass, {"book", "encyclopaedia"}) or -- {{cite book}}, {{cite encyclopedia}}; TODO: {{cite conference}} and others?
            ("citation" == config.CitationClass and utilities.is_set(Encyclopedia)) or -- {{citation}} as an encylopedia citation
            ("citation" == config.CitationClass and not utilities.is_set(Periodical))
     then -- {{citation}} as a book citation
        if utilities.is_set(PublicationPlace) then
            if not utilities.is_set(PublisherName) then
                local date = COinS_date.rftdate and tonumber(COinS_date.rftdate:match("%d%d%d%d")) -- get year portion of COinS date (because in Arabic numerals); convert string to number
                if date and (1850 <= date) then -- location has no publisher; if date is 1850 or later
                    utilities.set_message("maint_location_no_publisher") -- add maint cat
                end
            else -- PublisherName has a value
                if cfg.keywords_xlate["none"] == PublisherName then -- if that value is 'none' (only for book and encyclopedia citations)
                    PublisherName = "" -- unset
                end
            end
        end
    end

    local ID_list = {} -- sequence table of rendered identifiers
    local ID_list_coins = {} -- table of identifiers and their values from args; key is same as cfg.id_handlers's key
    local Class = A["Class"] -- arxiv class identifier

    local ID_support = {
        {A["ASINTLD"], "ASIN", "err_asintld_missing_asin", A:ORIGIN("ASINTLD")},
        {DoiBroken, "DOI", "err_doibroken_missing_doi", A:ORIGIN("DoiBroken")},
        {Embargo, "PMC", "err_embargo_missing_pmc", A:ORIGIN("Embargo")}
    }

    ID_list, ID_list_coins =
        identifiers.identifier_lists_get(
        args,
        {
            DoiBroken = DoiBroken, -- for |doi=
            ASINTLD = A["ASINTLD"], -- for |asin=
            Embargo = Embargo, -- for |pmc=
            Class = Class, -- for |arxiv=
            CitationClass = config.CitationClass, -- for |arxiv=
            Year = anchor_year -- for |isbn=
        },
        ID_support
    )

    -- Account for the oddities that are {{cite arxiv}}, {{cite biorxiv}}, {{cite citeseerx}}, {{cite medrxiv}}, {{cite ssrn}}, before generation of COinS data.
    if utilities.in_array(config.CitationClass, whitelist.preprint_template_list_t) then -- |arxiv= or |eprint= required for cite arxiv; |biorxiv=, |citeseerx=, |medrxiv=, |ssrn= required for their templates
        if
            not (args[cfg.id_handlers[config.CitationClass:upper()].parameters[1]] or -- can't use ID_list_coins k/v table here because invalid parameters omitted
                args[cfg.id_handlers[config.CitationClass:upper()].parameters[2]])
         then -- which causes unexpected parameter missing error message
            utilities.set_message("err_" .. config.CitationClass .. "_missing") -- add error message
        end

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

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

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

        if utilities.is_set(URL) then -- set when using an identifier-created URL
            if utilities.is_set(AccessDate) then -- |access-date= requires |url=; identifier-created URL is not |url=
                utilities.set_message("err_accessdate_missing_url") -- add an error message
                AccessDate = "" -- unset
            end

            if utilities.is_set(ArchiveURL) then -- |archive-url= requires |url=; identifier-created URL is not |url=
                utilities.set_message("err_archive_missing_url") -- add an error message
                ArchiveURL = "" -- 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 utilities.is_set(Title) and not utilities.is_set(TransTitle) and not utilities.is_set(ScriptTitle) then -- has special case for cite episode
        utilities.set_message("err_citation_missing_title", {"episode" == config.CitationClass and "series" or "title"})
    end

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

    if
        "journal" == config.CitationClass or
            ("citation" == config.CitationClass and utilities.is_set(Periodical) and "journal" == Periodical_origin)
     then
        if
            is_page_art_num(
                ((utilities.is_set(Page) and Page) or (utilities.is_set(Pages) and Pages)) or nil,
                ID_list_coins["DOI"]
            )
         then -- does |page(s)= look like it holds an article number
            utilities.set_message("maint_page_art_num") -- add maint cat
        end
    end

    -- COinS metadata (see <http://ocoins.info/>) for automated parsing of citation information.
    -- handle the oddity that is cite encyclopedia and {{citation |encyclopedia=something}}. Here we presume that
    -- when Periodical, Title, and Chapter are all set, then Periodical is the book (encyclopedia) title, Title
    -- is the article title, and Chapter is a section within the article.  So, we remap

    local coins_chapter = Chapter -- default assuming that remapping not required
    local coins_title = Title -- et tu
    if
        "encyclopaedia" == config.CitationClass or
            ("citation" == config.CitationClass and utilities.is_set(Encyclopedia))
     then
        if utilities.is_set(Chapter) and utilities.is_set(Title) and utilities.is_set(Periodical) then -- if all are used then
            coins_chapter = Title -- remap
            coins_title = Periodical
        end
    end
    local coins_author = a -- default for coins rft.au
    if 0 < #c then -- but if contributor list
        coins_author = c -- use that instead
    end

    -- this is the function call to COinS()
    local OCinSoutput =
        metadata.COinS(
        {
            ["Periodical"] = utilities.strip_apostrophe_markup(Periodical), -- no markup in the metadata
            ["Encyclopedia"] = Encyclopedia, -- just a flag; content ignored by ~/COinS
            ["Chapter"] = metadata.make_coins_title(coins_chapter, ScriptChapter), -- Chapter and ScriptChapter stripped of bold / italic / accept-as-written markup
            ["Degree"] = Degree, -- cite thesis only
            ["Title"] = metadata.make_coins_title(coins_title, ScriptTitle), -- Title and ScriptTitle stripped of bold / italic / accept-as-written markup
            ["PublicationPlace"] = PublicationPlace,
            ["Date"] = COinS_date.rftdate, -- COinS_date.* has correctly formatted date values if Date is valid;
            ["Season"] = COinS_date.rftssn,
            ["Quarter"] = COinS_date.rftquarter,
            ["Chron"] = COinS_date.rftchron,
            ["Series"] = Series,
            ["Volume"] = Volume,
            ["Issue"] = Issue,
            ["ArticleNumber"] = ArticleNumber,
            ["Pages"] = coins_pages or
                metadata.get_coins_pages(first_set({Sheet, Sheets, Page, Pages, At, QuotePage, QuotePages}, 7)), -- pages stripped of external links
            ["Edition"] = Edition,
            ["PublisherName"] = PublisherName or Newsgroup, -- any apostrophe markup already removed from PublisherName
            ["URL"] = first_set({ChapterURL, URL}, 2),
            ["Authors"] = coins_author,
            ["ID_list"] = ID_list_coins,
            ["RawPage"] = this_page.prefixedText
        },
        config.CitationClass
    )

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

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

    local Editors
    local EditorCount  -- used only for choosing {ed.) or (eds.) annotation at end of editor name-list
    local Contributors  -- assembled contributors name list
    local contributor_etal
    local Translators  -- assembled translators name list
    local translator_etal
    local t = {} -- translators list from |translator-lastn= / translator-firstn= pairs
    t = extract_names(args, "TranslatorList") -- fetch translator list from |translatorn= / |translator-lastn=, -firstn=, -linkn=, -maskn=
    local Interviewers
    local interviewers_list = {}
    interviewers_list = extract_names(args, "InterviewerList") -- process preferred interviewers parameters
    local interviewer_etal

    -- Now perform various field substitutions.
    -- We also add leading spaces and surrounding markup and punctuation to the
    -- various parts of the citation, but only when they are non-nil.
    do
        local last_first_list
        local control = {
            format = NameListStyle, -- empty string, '&', 'amp', 'and', or 'vanc'
            maximum = nil, -- as if display-authors or display-editors not set
            mode = Mode
        }

        do -- do editor name list first because the now unsupported coauthors used to modify control table
            local display_names, param =
                display_names_select(
                cfg.global_cs1_config_t["DisplayEditors"],
                A["DisplayEditors"],
                A:ORIGIN("DisplayEditors"),
                #e
            )
            control.maximum, editor_etal = get_display_names(display_names, #e, "editors", editor_etal, param)

            Editors, EditorCount = list_people(control, e, editor_etal)

            if 1 == EditorCount and (true == editor_etal or 1 < #e) then -- only one editor displayed but includes etal then
                EditorCount = 2 -- spoof to display (eds.) annotation
            end
        end
        do -- now do interviewers
            local display_names, param =
                display_names_select(
                cfg.global_cs1_config_t["DisplayInterviewers"],
                A["DisplayInterviewers"],
                A:ORIGIN("DisplayInterviewers"),
                #interviewers_list
            )
            control.maximum, interviewer_etal =
                get_display_names(display_names, #interviewers_list, "interviewers", interviewer_etal, param)

            Interviewers = list_people(control, interviewers_list, interviewer_etal)
        end
        do -- now do translators
            local display_names, param =
                display_names_select(
                cfg.global_cs1_config_t["DisplayTranslators"],
                A["DisplayTranslators"],
                A:ORIGIN("DisplayTranslators"),
                #t
            )
            control.maximum, translator_etal =
                get_display_names(display_names, #t, "translators", translator_etal, param)

            Translators = list_people(control, t, translator_etal)
        end
        do -- now do contributors
            local display_names, param =
                display_names_select(
                cfg.global_cs1_config_t["DisplayContributors"],
                A["DisplayContributors"],
                A:ORIGIN("DisplayContributors"),
                #c
            )
            control.maximum, contributor_etal =
                get_display_names(display_names, #c, "contributors", contributor_etal, param)

            Contributors = list_people(control, c, contributor_etal)
        end
        do -- now do authors
            local display_names, param =
                display_names_select(
                cfg.global_cs1_config_t["DisplayAuthors"],
                A["DisplayAuthors"],
                A:ORIGIN("DisplayAuthors"),
                #a,
                author_etal
            )
            control.maximum, author_etal = get_display_names(display_names, #a, "authors", author_etal, param)

            last_first_list = list_people(control, a, author_etal)

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

        if utilities.is_set(Authors) and utilities.is_set(Collaboration) then
            Authors = Authors .. " (" .. Collaboration .. ")" -- add collaboration after et al.
        end
    end

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

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

    if not utilities.is_set(URL) then
        if
            utilities.in_array(config.CitationClass, {"web", "podcast", "mailinglist"}) or -- |url= required for cite web, cite podcast, and cite mailinglist
                ("citation" == config.CitationClass and
                    ("website" == Periodical_origin or "script-website" == ScriptPeriodical_origin))
         then -- and required for {{citation}} with |website= or |script-website=
            utilities.set_message("err_cite_web_url")
        end

        -- do we have |accessdate= without either |url= or |chapter-url=?
        if utilities.is_set(AccessDate) and not utilities.is_set(ChapterURL) then -- ChapterURL may be set when URL is not set;
            utilities.set_message("err_accessdate_missing_url")
            AccessDate = ""
        end
    end

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

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

            if "live" ~= UrlStatus then -- if URL set then |archive-url= applies to it
                URL = ArchiveURL -- swap-in the archive's URL
                URL_origin = A:ORIGIN("ArchiveURL") -- name of archive URL parameter for error messages
                Format = ArchiveFormat or "" -- swap in archive's format
                UrlAccess = nil -- restricted access levels do not make sense for archived URLs
            end
        end
    elseif utilities.is_set(UrlStatus) then -- if |url-status= is set when |archive-url= is not set
        utilities.set_message("maint_url_status") -- add maint cat
    end

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

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

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

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

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

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

        if is_generic("generic_titles", Title) then
            utilities.set_message("err_generic_title") -- set an error message
        end
    end

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

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

    if utilities.is_set(Title) then -- TODO: is this the right place to be making Wikisource URLs?
        if utilities.is_set(TitleLink) and utilities.is_set(URL) then
            utilities.set_message("err_wikilink_in_url") -- set an error message because we can't have both
            TitleLink = "" -- unset
        end

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

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

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

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

        if utilities.is_set(Minutes) then
            if utilities.is_set(Time) then --TODO: make a function for this and similar?
                utilities.set_message(
                    "err_redundant_parameters",
                    {
                        utilities.wrap_style("parameter", "minutes") ..
                            cfg.presentation["sep_list_pair"] .. utilities.wrap_style("parameter", "time")
                    }
                )
            end
            Position = " " .. Minutes .. " " .. cfg.messages["minutes"]
        else
            if utilities.is_set(Time) then
                local TimeCaption = A["TimeCaption"]
                if not utilities.is_set(TimeCaption) then
                    TimeCaption = cfg.messages["event"]
                    if sepc ~= "." then
                        TimeCaption = TimeCaption:lower()
                    end
                end
                Position = " " .. TimeCaption .. " " .. Time
            end
        end
    else
        Position = " " .. Position
        At = ""
    end

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

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

        if utilities.is_set(Inset) then
            Inset = sepc .. " " .. wrap_msg("inset", Inset, use_lowercase)
        end

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

    local Others = A["Others"]
    if utilities.is_set(Others) and 0 == #a and 0 == #e then -- add maint cat when |others= has value and used without |author=, |editor=
        if config.CitationClass == "AV-media-notes" or config.CitationClass == "audio-visual" then -- special maint for AV/M which has a lot of 'false' positives right now
            utilities.set_message("maint_others_avm")
        else
            utilities.set_message("maint_others")
        end
    end
    Others = utilities.is_set(Others) and (sepc .. " " .. Others) or ""

    if utilities.is_set(Translators) then
        Others = safe_join({sepc .. " ", wrap_msg("translated", Translators, use_lowercase), Others}, sepc)
    end
    if utilities.is_set(Interviewers) then
        Others = safe_join({sepc .. " ", wrap_msg("interview", Interviewers, use_lowercase), Others}, sepc)
    end

    local TitleNote = A["TitleNote"]
    TitleNote = utilities.is_set(TitleNote) and (sepc .. " " .. TitleNote) or ""
    if utilities.is_set(Edition) then
        if Edition:match("%f[%a][Ee]d%n?%.?$") or Edition:match("%f[%a][Ee]dition$") then -- Ed, ed, Ed., ed., Edn, edn, Edn., edn.
            utilities.set_message("err_extra_text_edition") -- add error message
        end
        Edition = " " .. wrap_msg("edition", Edition)
    else
        Edition = ""
    end

    Series = utilities.is_set(Series) and wrap_msg("series", {sepc, Series}) or "" -- not the same as SeriesNum
    local Agency = A["Agency"] or "" -- |agency= is supported by {{cite magazine}}, {{cite news}}, {{cite press release}}, {{cite web}}, and certain {{citation}} templates
    if utilities.is_set(Agency) then -- this testing done here because {{citation}} supports 'news' citations
        if
            utilities.in_array(config.CitationClass, {"magazine", "news", "pressrelease", "web"}) or
                ("citation" == config.CitationClass and
                    utilities.in_array(Periodical_origin, {"magazine", "newspaper", "work"}))
         then
            Agency = wrap_msg("agency", {sepc, Agency}) -- format for rendering
        else
            Agency = "" -- unset; not supported
            utilities.set_message("err_parameter_ignored", {"agency"}) -- add error message
        end
    end

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

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

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

        AccessDate = utilities.substitute(cfg.presentation["accessdate"], {sepc, AccessDate}) -- allow editors to hide accessdates
    end

    if utilities.is_set(ID) then
        ID = sepc .. " " .. ID
    end

    local Docket = A["Docket"]
    if "thesis" == config.CitationClass and utilities.is_set(Docket) then
        ID = sepc .. " Docket " .. Docket .. ID
    end
    if "report" == config.CitationClass and utilities.is_set(Docket) then -- for cite report when |docket= is set
        ID = sepc .. " " .. Docket -- overwrite ID even if |id= is set
    end

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

    -- We check length of PostScript here because it will have been nuked by
    -- the quote parameters. We'd otherwise emit a message even if there wasn't
    -- a displayed postscript.
    -- TODO: Should the max size (1) be configurable?
    -- TODO: Should we check a specific pattern?
    if utilities.is_set(PostScript) and mw.ustring.len(PostScript) > 1 then
        utilities.set_message("maint_postscript")
    end

    local Archived
    if utilities.is_set(ArchiveURL) then
        if not utilities.is_set(ArchiveDate) then -- ArchiveURL set but ArchiveDate not set
            utilities.set_message("err_archive_missing_date") -- emit an error message
            ArchiveURL = "" -- empty string for concatenation
            ArchiveDate = "" -- empty string for concatenation
        end
    else
        if utilities.is_set(ArchiveDate) then -- ArchiveURL not set but ArchiveDate is set
            utilities.set_message("err_archive_date_missing_url") -- emit an error message
            ArchiveURL = "" -- empty string for concatenation
            ArchiveDate = "" -- empty string for concatenation
        end
    end

    if utilities.is_set(ArchiveURL) then
        local arch_text
        if "live" == UrlStatus then
            arch_text = cfg.messages["archived"]
            if sepc ~= "." then
                arch_text = arch_text:lower()
            end
            if utilities.is_set(ArchiveDate) then
                Archived =
                    sepc ..
                    " " ..
                        utilities.substitute(
                            cfg.messages["archived-live"],
                            {
                                external_link(ArchiveURL, arch_text, A:ORIGIN("ArchiveURL"), nil) .. ArchiveFormat,
                                ArchiveDate
                            }
                        )
            else
                Archived = ""
            end
            if not utilities.is_set(OriginalURL) then
                utilities.set_message("err_archive_missing_url")
                Archived = "" -- empty string for concatenation
            end
        elseif utilities.is_set(OriginalURL) then -- UrlStatus is empty, 'dead', 'unfit', 'usurped', 'bot: unknown'
            if utilities.in_array(UrlStatus, {"unfit", "usurped", "bot: unknown"}) then
                arch_text = cfg.messages["archived-unfit"]
                if sepc ~= "." then
                    arch_text = arch_text:lower()
                end
                Archived = sepc .. " " .. arch_text .. ArchiveDate -- format already styled
                if "bot: unknown" == UrlStatus then
                    utilities.set_message("maint_bot_unknown") -- and add a category if not already added
                else
                    utilities.add_prop_cat("unfit") -- and add a category if not already added
                end
            else -- UrlStatus is empty, 'dead'
                arch_text = cfg.messages["archived-dead"]
                if sepc ~= "." then
                    arch_text = arch_text:lower()
                end
                if utilities.is_set(ArchiveDate) then
                    Archived =
                        sepc ..
                        " " ..
                            utilities.substitute(
                                arch_text,
                                {
                                    external_link(
                                        OriginalURL,
                                        cfg.messages["original"],
                                        OriginalURL_origin,
                                        OriginalAccess
                                    ) .. OriginalFormat,
                                    ArchiveDate
                                }
                            ) -- format already styled
                else
                    Archived = "" -- unset for concatenation
                end
            end
        else -- OriginalUrl not set
            utilities.set_message("err_archive_missing_url")
            Archived = "" -- empty string for concatenation
        end
    elseif utilities.is_set(ArchiveFormat) then
        Archived = ArchiveFormat -- if set and ArchiveURL not set ArchiveFormat has error message
    else
        Archived = ""
    end

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

    local Publisher
    if utilities.is_set(PublicationDate) then
        PublicationDate = wrap_msg("published", PublicationDate)
    end
    if utilities.is_set(PublisherName) then
        if utilities.is_set(PublicationPlace) then
            Publisher = sepc .. " " .. PublicationPlace .. ": " .. PublisherName .. PublicationDate
        else
            Publisher = sepc .. " " .. PublisherName .. PublicationDate
        end
    elseif utilities.is_set(PublicationPlace) then
        Publisher = sepc .. " " .. PublicationPlace .. PublicationDate
    else
        Publisher = PublicationDate
    end

    -- Several of the above rely upon detecting this as nil, so do it last.
    if (utilities.is_set(Periodical) or utilities.is_set(ScriptPeriodical) or utilities.is_set(TransPeriodical)) then
        if utilities.is_set(Title) or utilities.is_set(TitleNote) then
            Periodical =
                sepc ..
                " " ..
                    format_periodical(
                        ScriptPeriodical,
                        ScriptPeriodical_origin,
                        Periodical,
                        TransPeriodical,
                        TransPeriodical_origin
                    )
        else
            Periodical =
                format_periodical(
                ScriptPeriodical,
                ScriptPeriodical_origin,
                Periodical,
                TransPeriodical,
                TransPeriodical_origin
            )
        end
    end

    local Language = A["Language"]
    if utilities.is_set(Language) then
        Language = language_parameter(Language) -- format, categories, name from ISO639-1, etc.
    else
        --[[ TODO: need to extract the wrap_msg from language_parameter
	so that we can solve parentheses bunching problem with Format/Language/TitleType
	]]
        Language = "" -- language not specified so make sure this is an empty string;
    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 = TitleType -- move TitleType to TitleNote so that it renders ahead of |event=
        TitleType = "" -- and unset

        if utilities.is_set(Periodical) then -- if Periodical, perhaps because of an included |website= or |journal= parameter
            if utilities.is_set(Conference) then -- and if |event= is set
                Conference = Conference .. sepc .. " " -- then add appropriate punctuation to the end of the Conference variable before rendering
            end
        end
    end

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

    local tcommon
    local tcommon2  -- used for book cite when |contributor= is set

    if utilities.in_array(config.CitationClass, {"book", "citation"}) and not utilities.is_set(Periodical) then -- special cases for book cites
        if utilities.is_set(Contributors) then -- when we are citing foreword, preface, introduction, etc.
            tcommon = safe_join({Title, TitleNote}, sepc) -- author and other stuff will come after this and before tcommon2
            tcommon2 = safe_join({TitleType, Series, Language, Volume, Others, Edition, Publisher}, sepc)
        else
            tcommon =
                safe_join({Title, TitleNote, TitleType, Series, Language, Volume, Others, Edition, Publisher}, sepc)
        end
    elseif "map" == config.CitationClass then -- special cases for cite map
        if utilities.is_set(Chapter) then -- map in a book; TitleType is part of Chapter
            tcommon = safe_join({Title, Edition, Scale, Series, Language, Cartography, Others, Publisher, Volume}, sepc)
        elseif utilities.is_set(Periodical) then -- map in a periodical
            tcommon =
                safe_join(
                {Title, TitleType, Periodical, Scale, Series, Language, Cartography, Others, Publisher, Volume},
                sepc
            )
        else -- a sheet or stand-alone map
            tcommon =
                safe_join({Title, TitleType, Edition, Scale, Series, Language, Cartography, Others, Publisher}, sepc)
        end
    elseif "episode" == config.CitationClass then -- special case for cite episode
        tcommon = safe_join({Title, TitleNote, TitleType, Series, Language, Edition, Publisher}, sepc)
    else -- all other CS1 templates
        tcommon =
            safe_join(
            {
                Title,
                TitleNote,
                Conference,
                Periodical,
                TitleType,
                Series,
                Language,
                Volume,
                Others,
                Edition,
                Publisher,
                Agency
            },
            sepc
        )
    end

    if #ID_list > 0 then
        ID_list = safe_join({sepc .. " ", table.concat(ID_list, sepc .. " "), ID}, sepc)
    else
        ID_list = ID
    end

    local Via = A["Via"]
    Via = utilities.is_set(Via) and wrap_msg("via", Via) or ""
    local idcommon
    if "audio-visual" == config.CitationClass or "episode" == config.CitationClass then -- special case for cite AV media & cite episode position transcript
        idcommon = safe_join({ID_list, URL, Archived, Transcript, AccessDate, Via, Quote}, sepc)
    else
        idcommon = safe_join({ID_list, URL, Archived, AccessDate, Via, Quote}, sepc)
    end

    local text
    local pgtext = Position .. Sheet .. Sheets .. Page .. Pages .. At

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

    if utilities.is_set(PostScript) and PostScript ~= sepc then
        text = safe_join({text, sepc}, sepc) -- Deals with italics, spaces, etc.
        if "." == sepc then -- remove final seperator if present
            text = text:gsub("%" .. sepc .. "$", "") -- dot must be escaped here
        else
            text = mw.ustring.gsub(text, sepc .. "$", "") -- using ustring for non-dot sepc (likely a non-Latin character)
        end
    end

    text = safe_join({text, PostScript}, sepc)

    -- Now enclose the whole thing in a <cite> element
    local options_t = {}
    options_t.class = cite_class_attribute_make(config.CitationClass, Mode)

    local Ref = is_valid_parameter_value(A["Ref"], A:ORIGIN("Ref"), cfg.keywords_lists["ref"], nil, true) -- nil when |ref=harv; A['Ref'] else

    if "none" ~= cfg.keywords_xlate[(Ref and Ref:lower()) or ""] then
        local namelist_t = {} -- 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_t = c -- select it
        elseif #a > 0 then -- or an author list
            namelist_t = a
        elseif #e > 0 then -- or an editor list
            namelist_t = e
        end
        local citeref_id
        if #namelist_t > 0 then -- if there are names in namelist_t
            citeref_id = make_citeref_id(namelist_t, year) -- go make the CITEREF anchor
            if mw.uri.anchorEncode(citeref_id) == ((Ref and mw.uri.anchorEncode(Ref)) or "") then -- Ref may already be encoded (by {{sfnref}}) so citeref_id must be encoded before comparison
                utilities.set_message("maint_ref_duplicates_default")
            end
        else
            citeref_id = "" -- unset
        end
        options_t.id = Ref or citeref_id
    end

    if string.len(text:gsub("%b<>", "")) <= 2 then -- remove html and html-like tags; then get length of what remains;
        z.error_cats_t = {} -- blank the categories list
        z.error_msgs_t = {} -- blank the error messages list
        OCinSoutput = nil -- blank the metadata string
        text = "" -- blank the the citation
        utilities.set_message("err_empty_citation") -- set empty citation message and category
    end

    local render_t = {} -- here we collect the final bits for concatenation into the rendered citation

    if utilities.is_set(options_t.id) then -- here we wrap the rendered citation in <cite ...>...</cite> tags
        table.insert(
            render_t,
            utilities.substitute(
                cfg.presentation["cite-id"],
                {mw.uri.anchorEncode(options_t.id), mw.text.nowiki(options_t.class), text}
            )
        ) -- when |ref= is set or when there is a namelist
    else
        table.insert(render_t, utilities.substitute(cfg.presentation["cite"], {mw.text.nowiki(options_t.class), text})) -- when |ref=none or when namelist_t empty and |ref= is missing or is empty
    end

    if OCinSoutput then -- blanked when citation is 'empty' so don't bother to add boilerplate metadata span
        table.insert(render_t, utilities.substitute(cfg.presentation["ocins"], OCinSoutput)) -- format and append metadata to the citation
    end

    local template_name =
        ("citation" == config.CitationClass) and "citation" or
        "cite " .. (cfg.citation_class_map_t[config.CitationClass] or config.CitationClass)
    local template_link = "[[Template:" .. template_name .. "|" .. template_name .. "]]"
    local msg_prefix = '<code class="cs1-code">{{' .. template_link .. "}}</code>: "

    if 0 ~= #z.error_msgs_t then
        mw.addWarning(utilities.substitute(cfg.messages.warning_msg_e, template_link))

        table.insert(render_t, " ") -- insert a space between citation and its error messages
        table.sort(z.error_msgs_t) -- sort the error messages list; sorting includes wrapping <span> and <code> tags; hidden-error sorts ahead of visible-error

        local hidden = true -- presume that the only error messages emited by this template are hidden
        for _, v in ipairs(z.error_msgs_t) do -- spin through the list of error messages
            if v:find("cs1-visible-error", 1, true) then -- look for the visible error class name
                hidden = false -- found one; so don't hide the error message prefix
                break -- and done because no need to look further
            end
        end

        z.error_msgs_t[1] = table.concat({utilities.error_comment(msg_prefix, hidden), z.error_msgs_t[1]}) -- add error message prefix to first error message to prevent extraneous punctuation
        table.insert(render_t, table.concat(z.error_msgs_t, "; ")) -- make a big string of error messages and add it to the rendering
    end

    if 0 ~= #z.maint_cats_t then
        mw.addWarning(utilities.substitute(cfg.messages.warning_msg_m, template_link))

        table.sort(z.maint_cats_t) -- sort the maintenance messages list

        local maint_msgs_t = {} -- here we collect all of the maint messages

        if 0 == #z.error_msgs_t then -- if no error messages
            table.insert(maint_msgs_t, msg_prefix) -- insert message prefix in maint message livery
        end

        for _, v in ipairs(z.maint_cats_t) do -- append maintenance categories
            table.insert(
                maint_msgs_t, -- assemble new maint message and add it to the maint_msgs_t table
                table.concat({v, " (", utilities.substitute(cfg.messages[":cat wikilink"], v), ")"})
            )
        end
        table.insert(render_t, utilities.substitute(cfg.presentation["hidden-maint"], table.concat(maint_msgs_t, " "))) -- wrap the group of maint messages with proper presentation and save
    end

    if not no_tracking_cats then
        local sort_key
        local cat_wikilink = "cat wikilink"
        if cfg.enable_sort_keys then -- when namespace sort keys enabled
            local namespace_number = mw.title.getCurrentTitle().namespace -- get namespace number for this wikitext
            sort_key =
                (0 ~= namespace_number and
                (cfg.name_space_sort_keys[namespace_number] or cfg.name_space_sort_keys.other)) or
                nil -- get sort key character; nil for mainspace
            cat_wikilink = (not sort_key and "cat wikilink") or "cat wikilink sk" -- make <cfg.messages> key
        end

        for _, v in ipairs(z.error_cats_t) do -- append error categories
            table.insert(render_t, utilities.substitute(cfg.messages[cat_wikilink], {v, sort_key}))
        end
        if cfg.id_limits_data_load_fail then -- boolean true when load failed
            utilities.set_message("maint_id_limit_load_fail") -- done here because this maint cat emits no message
        end
        for _, v in ipairs(z.maint_cats_t) do -- append maintenance categories
            table.insert(render_t, utilities.substitute(cfg.messages[cat_wikilink], {v, sort_key}))
        end
        for _, v in ipairs(z.prop_cats_t) do -- append properties categories
            table.insert(render_t, utilities.substitute(cfg.messages["cat wikilink"], v)) -- no sort keys
        end
    end

    return table.concat(render_t) -- make a big string and done
end

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

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

Parameters in the whitelist can have three values:
	true - active, supported parameters
	false - deprecated, supported parameters
	nil - unsupported parameters
	
]]
local function validate(name, cite_class, empty)
    local name = tostring(name)
    local enum_name  -- parameter name with enumerator (if any) replaced with '#'
    local state
    local function state_test(state, name) -- local function to do testing of state values
        if true == state then
            return true
        end -- valid actively supported parameter
        if false == state then
            if empty then
                return nil
            end -- empty deprecated parameters are treated as unknowns
            deprecated_parameter(name) -- parameter is deprecated but still supported
            return true
        end
        if "tracked" == state then
            local base_name = name:gsub("%d", "") -- strip enumerators from parameter names that have them to get the base name
            utilities.add_prop_cat("tracked-param", {base_name}, base_name) -- add a properties category; <base_name> modifies <key>
            return true
        end
        return nil
    end

    if name:find("#") then -- # is a cs1|2 reserved character so parameters with # not permitted
        return nil
    end
    -- replace enumerator digit(s) with # (|last25= becomes |last#=) (mw.ustring because non-Western 'local' digits)
    enum_name = mw.ustring.gsub(name, "%d+$", "#") -- where enumerator is last charaters in parameter name (these to protect |s2cid=)
    enum_name = mw.ustring.gsub(enum_name, "%d+([%-l])", "#%1") -- where enumerator is in the middle of the parameter name; |author#link= is the oddity

    if "document" == cite_class then -- special case for {{cite document}}
        state = whitelist.document_parameters_t[enum_name] -- this list holds enumerated and nonenumerated parameters
        if true == state_test(state, name) then
            return true
        end

        return false
    end

    if utilities.in_array(cite_class, whitelist.preprint_template_list_t) then -- limited parameter sets allowed for these templates
        state = whitelist.limited_parameters_t[enum_name] -- this list holds enumerated and nonenumerated parameters
        if true == state_test(state, name) then
            return true
        end

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

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

    if utilities.in_array(cite_class, whitelist.unique_param_template_list_t) then -- template-specific parameters for templates that accept parameters from the basic argument list
        state = whitelist.unique_arguments_t[cite_class][name] -- look in the template-specific parameter-lists for the template identified by cite_class
        if true == state_test(state, name) then
            return true
        end
    end -- if here, fall into general validation

    state = whitelist.common_parameters_t[enum_name] -- all other templates; all normal parameters allowed; this list holds enumerated and nonenumerated parameters
    if true == state_test(state, name) then
        return true
    end

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

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

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

return value as is else

]=]

local function inter_wiki_check(parameter, value)
    local prefix = value:match("%[%[(%a+):") -- get an interwiki prefix if one exists
    local _

    if prefix and cfg.inter_wiki_map[prefix:lower()] then -- if prefix is in the map, needs preceding colon so
        utilities.set_message("err_bad_paramlink", parameter) -- emit an error message
        _, value, _ = utilities.is_wikilink(value) -- extract label portion from wikilink
    end

    return value
end

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

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

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

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

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

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

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

]]
local function has_extraneous_punc(param, value)
    if "number" == type(param) then
        return
    end

    param = param:gsub("%d+", "#") -- enumerated name-list mask params allow terminal punct; normalize
    if cfg.punct_skip[param] then
        return -- parameter name found in the skip table so done
    end

    if value:match("[,;:]$") then
        utilities.set_message("maint_extra_punct") -- has extraneous punctuation; add maint cat
    end
    if value:match("^=") then -- sometimes an extraneous '=' character appears ...
        utilities.set_message("maint_extra_punct") -- has extraneous punctuation; add maint cat
    end
end

--[[--------------------------< H A S _ T W L _ U R L >--------------------------------------------------------

look for The Wikipedia Library urls in url-holding parameters.  TWL urls are accessible only for readers who are
active extended confirmed Wikipedia editors.  This function sets an error message when such urls are discovered
and when appropriate, sets the |<param>-url-access=subscription.  returns nothing.

looks for: '.wikipedialibrary.idm.oclc.org'

]]
local function has_twl_url(url_params_t, cite_args_t)
    local url_error_t = {} -- sequence of url-holding parameters that have a TWL url

    for param, value in pairs(url_params_t) do
        if value:find("%.wikipedialibrary%.idm%.oclc%.org") then -- has the TWL base url?
            table.insert(url_error_t, param) -- add parameter name to the error list
        end
    end
    if 0 ~= #url_error_t then -- non-zero when there are errors
        table.sort(url_error_t) -- sor for error messaging
        for i, param in ipairs(url_error_t) do
            if cfg.url_access_map_t[param] then -- if <param> has a matching -access parameter
                cite_args_t[cfg.url_access_map_t[param]] = cfg.keywords_xlate.subscription -- set |<param>-url-access=subscription
            end
            url_error_t[i] = utilities.wrap_style("parameter", param) -- make the parameter pretty for error message
        end

        utilities.set_message("err_param_has_twl_url", {utilities.make_sep_list(#url_error_t, url_error_t)}) -- add this error message
    end
end

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

look for extraneous url parameter values; parameters listed in skip table are not checked

]]
local function has_extraneous_url(non_url_param_t)
    local url_error_t = {}

    check_for_url(non_url_param_t, url_error_t) -- extraneous url check
    if 0 ~= #url_error_t then -- non-zero when there are errors
        table.sort(url_error_t)
        utilities.set_message("err_param_has_ext_link", {utilities.make_sep_list(#url_error_t, url_error_t)}) -- add this error message
    end
end

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

Module entry point

	frame – from template call (citation()); may be nil when called from another module
	args_t – table of all cs1|2 parameters in the template (the parent frame)
	config_t – table of template-supplied parameter (the #invoke frame)

]]
local function _citation(frame, args_t, config_t) -- save a copy in case we need to display an error message in preview mode
    if not frame then
        frame = mw.getCurrentFrame() -- if called from another module, get a frame for frame-provided functions
    end
    -- i18n: set the name that your wiki uses to identify sandbox subpages from sandbox template invoke (or can be set here)
    local sandbox = ((config_t.SandboxPath and "" ~= config_t.SandboxPath) and config_t.SandboxPath) or "/sandbox" -- sandbox path from {{#invoke:Citation/CS1/sandbox|citation|SandboxPath=/...}}
    is_sandbox = nil ~= string.find(frame:getTitle(), sandbox, 1, true) -- is this invoke the sandbox module?
    sandbox = is_sandbox and sandbox or "" -- use i18n sandbox to load sandbox modules when this module is the sandox; live modules else

    cfg = mw.loadData("Module:Citation/CS1/Configuration" .. sandbox) -- load sandbox versions of support modules when {{#invoke:Citation/CS1/sandbox|...}}; live modules else
    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)

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

    z = utilities.z -- table of error and category tables in Module:Citation/CS1/Utilities
    local cite_args_t = {} -- because args_t is the parent (template) frame args (which cannot be modified); params and their values will be placed here

    is_preview_mode = not utilities.is_set(frame:preprocess("{{REVISIONID}}"))

    local suggestions = {} -- table where we store suggestions if we need to loadData them
    local error_text  -- used as a flag

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

            cite_args_t[k] = v -- save this parameter and its value
        elseif not utilities.is_set(v) then -- for empty parameters
            if not validate(k, config_t.CitationClass, true) then -- is this empty parameter a valid parameter
                k = ("" == k) and "(empty string)" or k -- when k is empty string (or was space(s) trimmed to empty string), replace with descriptive text
                table.insert(empty_unknowns, utilities.wrap_style("parameter", k)) -- format for error message and add to the list
            end
        end
    end

    if 0 ~= #empty_unknowns then -- create empty unknown error message
        utilities.set_message(
            "err_param_unknown_empty",
            {
                1 == #empty_unknowns and "" or "s",
                utilities.make_sep_list(#empty_unknowns, empty_unknowns)
            }
        )
    end

    local non_url_param_t = {} -- table of parameters and values that are not url-holding parameters
    local url_param_t = {} -- table of url-holding paramters and their values

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

        if "string" == type(k) then -- when parameter k is not positional
            if not cfg.url_skip[k] then -- and not in url skip table
                non_url_param_t[k] = v -- make a parameter/value list for extraneous url check
            else -- and is in url skip table (a url-holding parameter)
                url_param_t[k] = v -- make a parameter/value list to check for values that are The Wikipedia Library url
            end
        end
    end

    has_extraneous_url(non_url_param_t) -- look for url in parameter values where a url does not belong
    has_twl_url(url_param_t, cite_args_t) -- look for url-holding parameters that hold a The Wikipedia Library url

    return table.concat(
        {
            frame:extensionTag("templatestyles", "", {src = "Module:Citation/CS1" .. sandbox .. "/styles.css"}),
            citation0(config_t, cite_args_t)
        }
    )
end

--[[---------------------------< C I T A T I O N >------------------------------
  Template entry point.
]]
local function citation(frame)
  local config_t = {}  -- Table to store parameters from the module {{#invoke:}}
  local args_t   = frame:getParent().args  -- Get template's preset parameters.

  for k, v in pairs(frame.args) do  -- Get parameters from the {{#invoke}} frame
    config_t[k]  = v
    -- Crude debug support that allows us to render a citation from module
    -- {{#invoke:}}, skipping parameter validation. TODO: Keep?
    -- args_t[k] = v
  end
  return _citation(frame, args_t, config_t)
end

--[[-----------------< E X P O R T E D   F U N C T I O N S >------------------]]
return {
  citation  = citation,  -- Template entry point.
  _citation = _citation  -- Module entry point.
}