Module:Citation/CS1/Identifiers

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This page renders and performs error checking on the various named identifiers supported by Module:Citation/CS1.

These files comprise the module support for CS1 | CS2 citation templates:

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

--[[--------------------------< F O R W A R D   D E C L A R A T I O N S >--------------------------------------
]]
local has_accept_as_written,
    is_set,
    in_array,
    set_message,
    select_one, -- functions in Module:Citation/CS1/Utilities
    substitute,
    make_wikilink

local z  -- table of tables defined in Module:Citation/CS1/Utilities

local cfg  -- table of configuration tables that are defined in Module:Citation/CS1/Configuration

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

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

]]
local auto_link_urls = {} -- holds identifier URLs for those identifiers that can auto-link |title=

--============================<< H E L P E R   F U N C T I O N S >>============================================

--[[--------------------------< W I K I D A T A _ A R T I C L E _ N A M E _ G E T >----------------------------

as an aid to internationalizing identifier-label wikilinks, gets identifier article names from Wikidata.

returns w:<lang code>:<article title> when <q> has an <article title> for <lang code>; nil else. 'w:<lang code>'
ensures that sister project (like wiktionary) will link to the <lang code>.wikipedia article.

for identifiers that do not have <q>, returns nil

for wikis that do not have mw.wikibase installed, returns nil

]]
local function wikidata_article_name_get(q)
    if not is_set(q) or (q and not mw.wikibase) then -- when no q number or when a q number but mw.wikibase not installed on this wiki
        return nil -- abandon
    end

    local wd_article
    local this_wiki_code = cfg.this_wiki_code -- Wikipedia subdomain; 'en' for en.wikipedia.org

    wd_article = mw.wikibase.getSitelink(q, this_wiki_code .. "wiki") -- fetch article title from WD; nil when no title available at this wiki

    if wd_article then
        wd_article = table.concat({"w:", this_wiki_code, ":", wd_article}) -- interwiki-style link without brackets if taken from WD; leading 'w:' required
    end

    return wd_article -- article title from WD; nil else
end

--[[--------------------------< L A B E L _ L I N K _ M A K E >------------------------------------------------

common function to create a link for an identifier label from handler table or from Wikidata

returns the first available of:
	1. redirect from local wiki's handler table (if enabled)
	2. Wikidata sitelink to the local language wikipedia article (if there is a Wikidata entry for this identifier in the local language)
	3. link to wikipedia article specified in the local wiki's handler table
	
]]
local function label_link_make(handler)
    local wd_article

    if not (cfg.use_identifier_redirects and is_set(handler.redirect)) then -- redirect has priority so if enabled and available don't fetch from Wikidata because expensive
        wd_article = wikidata_article_name_get(handler.q) -- if Wikidata has an article title for this wiki, get it;
    end

    return (cfg.use_identifier_redirects and is_set(handler.redirect) and handler.redirect) or wd_article or
        handler.link
end

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

Formats a wiki-style external link

]]
local function external_link_id(options)
    local url_string = options.id
    local ext_link
    local this_wiki_code = cfg.this_wiki_code -- Wikipedia subdomain; 'en' for en.wikipedia.org
    local wd_article  -- article title from Wikidata

    if options.encode == true or options.encode == nil then
        url_string = mw.uri.encode(url_string, "PATH")
    end

    if options.auto_link and is_set(options.access) then
        auto_link_urls[options.auto_link] = table.concat({options.prefix, url_string, options.suffix})
    end

    ext_link =
        mw.ustring.format("[%s%s%s %s]", options.prefix, url_string, options.suffix or "", mw.text.nowiki(options.id))
    if is_set(options.access) then
        ext_link =
            substitute(
            cfg.presentation["ext-link-access-signal"],
            {cfg.presentation[options.access].class, cfg.presentation[options.access].title, ext_link}
        ) -- add the free-to-read / paywall lock
    end

    return table.concat(
        {
            make_wikilink(label_link_make(options), options.label), -- redirect, Wikidata link, or locally specified link (in that order)
            options.separator or "&nbsp;",
            ext_link
        }
    )
end

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

Formats a wiki-style internal link

TODO: Does not currently need to support options.access, options.encode, auto-linking and COinS (as in external_link_id),
but may be needed in the future for :m:Interwiki_map custom-prefixes like :arxiv:, :bibcode:, :DOI:, :hdl:, :ISSN:,
:JSTOR:, :Openlibrary:, :PMID:, :RFC:.

]]
local function internal_link_id(options)
    local id = mw.ustring.gsub(options.id, "%d", cfg.date_names.local_digits) -- translate 'local' digits to Western 0-9

    return table.concat(
        {
            make_wikilink(label_link_make(options), options.label), -- wiki-link the identifier label
            options.separator or "&nbsp;", -- add the separator
            make_wikilink(
                table.concat(
                    {
                        options.prefix,
                        id, -- translated to Western digits
                        options.suffix or ""
                    }
                ),
                substitute(cfg.presentation["bdi"], {"", mw.text.nowiki(options.id)}) -- bdi tags to prevent Latin script identifiers from being reversed at RTL language wikis
            ) -- nowiki because MediaWiki still has magic links for ISBN and the like; TODO: is it really required?
        }
    )
end

--[[--------------------------< I S _ E M B A R G O E D >------------------------------------------------------

Determines if a PMC identifier's online version is embargoed. Compares the date in |pmc-embargo-date= against
today's date.  If embargo date is in the future, returns the content of |pmc-embargo-date=; otherwise, returns
an empty string because the embargo has expired or because |pmc-embargo-date= was not set in this cite.

]]
local function is_embargoed(embargo)
    if is_set(embargo) then
        local lang = mw.getContentLanguage()
        local good1, embargo_date, todays_date
        good1, embargo_date = pcall(lang.formatDate, lang, "U", embargo)
        todays_date = lang:formatDate("U")

        if good1 then -- if embargo date is a good date
            if tonumber(embargo_date) >= tonumber(todays_date) then -- is embargo date is in the future?
                return embargo -- still embargoed
            else
                set_message("maint_pmc_embargo") -- embargo has expired; add main cat
                return "" -- unset because embargo has expired
            end
        end
    end
    return "" -- |pmc-embargo-date= not set return empty string
end

--[=[-------------------------< I S _ V A L I D _ R X I V _ D A T E >------------------------------------------

for biorxiv, returns true if:
	2019-12-11T00:00Z <= biorxiv_date < today + 2 days
for medrxiv, returns true if:
	2020-01-01T00:00Z <= medrxiv_date < today + 2 days
	
The dated form of biorxiv identifier has a start date of 2019-12-11.  The Unix timestamp for that date is {{#time:U|2019-12-11}} = 1576022400
The medrxiv identifier has a start date of 2020-01-01.  The Unix timestamp for that date is {{#time:U|2020-01-01}} = 1577836800

<rxiv_date> is the date provided in those |biorxiv= parameter values that are dated and in |medrxiv= parameter values at time 00:00:00 UTC
<today> is the current date at time 00:00:00 UTC plus 48 hours
	if today's date is 2023-01-01T00:00:00 then
		adding 24 hours gives 2023-01-02T00:00:00 – one second more than today
		adding 24 hours gives 2023-01-03T00:00:00 – one second more than tomorrow

inputs:
	<y>, <m>, <d> – year, month, day parts of the date from the birxiv or medrxiv identifier
	<select> 'b' for biorxiv, 'm' for medrxiv; defaults to 'b'

]=]

local function is_valid_rxiv_date(y, m, d, select)
    if 0 == tonumber(m) and 12 < tonumber(m) then -- <m> must be a number 1–12
        return false
    end
    if 0 == tonumber(d) and 31 < tonumber(d) then -- <d> must be a number 1–31; TODO: account for month length and leap yer?
        return false
    end

    local rxiv_date = table.concat({y, m, d}, "-") -- make ymd date string
    local good1, good2
    local rxiv_ts, tomorrow_ts  -- to hold Unix timestamps representing the dates
    local lang_object = mw.getContentLanguage()

    good1, rxiv_ts = pcall(lang_object.formatDate, lang_object, "U", rxiv_date) -- convert rxiv_date value to Unix timestamp
    good2, tomorrow_ts = pcall(lang_object.formatDate, lang_object, "U", "today + 2 days") -- today midnight + 2 days is one second more than all day tomorrow

    if good1 and good2 then -- lang.formatDate() returns a timestamp in the local script which tonumber() may not understand
        rxiv_ts = tonumber(rxiv_ts) or lang_object:parseFormattedNumber(rxiv_ts) -- convert to numbers for the comparison;
        tomorrow_ts = tonumber(tomorrow_ts) or lang_object:parseFormattedNumber(tomorrow_ts)
    else
        return false -- one or both failed to convert to Unix timestamp
    end

    local limit_ts = ((select and ("m" == select)) and 1577836800) or 1576022400 -- choose the appropriate limit timesatmp

    return ((limit_ts <= rxiv_ts) and (rxiv_ts < tomorrow_ts)) -- limit_ts <= rxiv_date < tomorrow's date
end

--[[--------------------------< IS _ V A L I D _ I S X N >-----------------------------------------------------

ISBN-10 and ISSN validator code calculates checksum across all ISBN/ISSN digits including the check digit.
ISBN-13 is checked in isbn().

If the number is valid the result will be 0. Before calling this function, ISBN/ISSN must be checked for length
and stripped of dashes, spaces and other non-ISxN characters.

]]
local function is_valid_isxn(isxn_str, len)
    local temp = 0
    isxn_str = {isxn_str:byte(1, len)} -- make a table of byte values '0' → 0x30 .. '9' → 0x39, 'X' → 0x58
    len = len + 1 -- adjust to be a loop counter
    for i, v in ipairs(isxn_str) do -- loop through all of the bytes and calculate the checksum
        if v == string.byte("X") then -- if checkdigit is X (compares the byte value of 'X' which is 0x58)
            temp = temp + 10 * (len - i) -- it represents 10 decimal
        else
            temp = temp + tonumber(string.char(v)) * (len - i)
        end
    end
    return temp % 11 == 0 -- returns true if calculation result is zero
end

--[[--------------------------< IS _ V A L I D _ I S X N _ 1 3 >-----------------------------------------------

ISBN-13 and ISMN validator code calculates checksum across all 13 ISBN/ISMN digits including the check digit.
If the number is valid, the result will be 0. Before calling this function, ISBN-13/ISMN must be checked for length
and stripped of dashes, spaces and other non-ISxN-13 characters.

]]
local function is_valid_isxn_13(isxn_str)
    local temp = 0

    isxn_str = {isxn_str:byte(1, 13)} -- make a table of byte values '0' → 0x30 .. '9' → 0x39
    for i, v in ipairs(isxn_str) do
        temp = temp + (3 - 2 * (i % 2)) * tonumber(string.char(v)) -- multiply odd index digits by 1, even index digits by 3 and sum; includes check digit
    end
    return temp % 10 == 0 -- sum modulo 10 is zero when ISBN-13/ISMN is correct
end

--[[--------------------------< N O R M A L I Z E _ L C C N >--------------------------------------------------

LCCN normalization (https://www.loc.gov/marc/lccn-namespace.html#normalization)
1. Remove all blanks.
2. If there is a forward slash (/) in the string, remove it, and remove all characters to the right of the forward slash.
3. If there is a hyphen in the string:
	a. Remove it.
	b. Inspect the substring following (to the right of) the (removed) hyphen. Then (and assuming that steps 1 and 2 have been carried out):
		1. All these characters should be digits, and there should be six or less. (not done in this function)
		2. If the length of the substring is less than 6, left-fill the substring with zeroes until the length is six.

Returns a normalized LCCN for lccn() to validate.  There is no error checking (step 3.b.1) performed in this function.

]]
local function normalize_lccn(lccn)
    lccn = lccn:gsub("%s", "") -- 1. strip whitespace

    if nil ~= string.find(lccn, "/") then
        lccn = lccn:match("(.-)/") -- 2. remove forward slash and all character to the right of it
    end

    local prefix
    local suffix
    prefix, suffix = lccn:match("(.+)%-(.+)") -- 3.a remove hyphen by splitting the string into prefix and suffix

    if nil ~= suffix then -- if there was a hyphen
        suffix = string.rep("0", 6 - string.len(suffix)) .. suffix -- 3.b.2 left fill the suffix with 0s if suffix length less than 6
        lccn = prefix .. suffix -- reassemble the LCCN
    end

    return lccn
end

--============================<< I D E N T I F I E R   F U N C T I O N S >>====================================

--[[--------------------------< A R X I V >--------------------------------------------------------------------

See: https://arxiv.org/help/arxiv_identifier

format and error check arXiv identifier.  There are three valid forms of the identifier:
the first form, valid only between date codes 9107 and 0703, is:
	arXiv:<archive>.<class>/<date code><number><version>
where:
	<archive> is a string of alpha characters - may be hyphenated; no other punctuation
	<class> is a string of alpha characters - may be hyphenated; no other punctuation; not the same as |class= parameter which is not supported in this form
	<date code> is four digits in the form YYMM where YY is the last two digits of the four-digit year and MM is the month number January = 01
		first digit of YY for this form can only 9 and 0
	<number> is a three-digit number
	<version> is a 1 or more digit number preceded with a lowercase v; no spaces (undocumented)
	
the second form, valid from April 2007 through December 2014 is:
	arXiv:<date code>.<number><version>
where:
	<date code> is four digits in the form YYMM where YY is the last two digits of the four-digit year and MM is the month number January = 01
	<number> is a four-digit number
	<version> is a 1 or more digit number preceded with a lowercase v; no spaces

the third form, valid from January 2015 is:
	arXiv:<date code>.<number><version>
where:
	<date code> and <version> are as defined for 0704-1412
	<number> is a five-digit number

]]
local function arxiv(options)
    local id = options.id
    local class = options.Class -- TODO: lowercase?
    local handler = options.handler
    local year, month, version
    local err_msg = false -- assume no error message
    local text  -- output text

    if id:match("^%a[%a%.%-]+/[90]%d[01]%d%d%d%d$") or id:match("^%a[%a%.%-]+/[90]%d[01]%d%d%d%dv%d+$") then -- test for the 9107-0703 format with or without version
        year, month = id:match("^%a[%a%.%-]+/([90]%d)([01]%d)%d%d%d[v%d]*$")
        year = tonumber(year)
        month = tonumber(month)
        if
            ((not (90 < year or 8 > year)) or (1 > month or 12 < month)) or -- if invalid year or invalid month
                ((91 == year and 7 > month) or (7 == year and 3 < month))
         then -- if years ok, are starting and ending months ok?
            err_msg = true -- flag for error message
        end
    elseif id:match("^%d%d[01]%d%.%d%d%d%d$") or id:match("^%d%d[01]%d%.%d%d%d%dv%d+$") then -- test for the 0704-1412 with or without version
        year, month = id:match("^(%d%d)([01]%d)%.%d%d%d%d[v%d]*$")
        year = tonumber(year)
        month = tonumber(month)
        if
            ((7 > year) or (14 < year) or (1 > month or 12 < month)) or -- is year invalid or is month invalid? (doesn't test for future years)
                ((7 == year) and (4 > month))
         then -- when year is 07, is month invalid (before April)?
            err_msg = true -- flag for error message
        end
    elseif id:match("^%d%d[01]%d%.%d%d%d%d%d$") or id:match("^%d%d[01]%d%.%d%d%d%d%dv%d+$") then -- test for the 1501- format with or without version
        year, month = id:match("^(%d%d)([01]%d)%.%d%d%d%d%d[v%d]*$")
        year = tonumber(year)
        month = tonumber(month)
        if ((15 > year) or (1 > month or 12 < month)) then -- is year invalid or is month invalid? (doesn't test for future years)
            err_msg = true -- flag for error message
        end
    else
        err_msg = true -- not a recognized format; flag for error message
    end

    if err_msg then
        options.coins_list_t["ARXIV"] = nil -- when error, unset so not included in COinS
    end

    local err_msg_t = {}
    if err_msg then
        set_message("err_bad_arxiv")
    end

    text =
        external_link_id(
        {
            link = handler.link,
            label = handler.label,
            q = handler.q,
            redirect = handler.redirect,
            prefix = handler.prefix,
            id = id,
            separator = handler.separator,
            encode = handler.encode,
            access = handler.access
        }
    )

    if is_set(class) then
        if id:match("^%d+") then
            text = table.concat({text, " [[https://arxiv.org/archive/", class, " ", class, "]]"}) -- external link within square brackets, not wikilink
        else
            set_message("err_class_ignored")
        end
    else -- class not set
        if id:match("^%d+") and options.CitationClass == "arxiv" then -- new (post 2007) format; {{cite arxiv}} only
            set_message("maint_missing_class") -- add maint cat
        end
    end

    return text
end

--[[--------------------------< B I B C O D E >--------------------------------------------------------------------

Validates (sort of) and formats a bibcode ID.

Format for bibcodes is specified here: https://adsabs.harvard.edu/abs_doc/help_pages/data.html#bibcodes

But, this: 2015arXiv151206696F is apparently valid so apparently, the only things that really matter are length, 19 characters
and first four digits must be a year.  This function makes these tests:
	length must be 19 characters
	characters in position
		1–4 must be digits and must represent a year in the range of 1000 – next year
		5 must be a letter
		6–8 must be letter, digit, ampersand, or dot (ampersand cannot directly precede a dot; &. )
		9–18 must be letter, digit, or dot
		19 must be a letter or dot

]]
local function bibcode(options)
    local id = options.id
    local access = options.access
    local handler = options.handler
    local ignore_invalid = options.accept
    local err_type
    local err_msg = ""
    local year

    local text =
        external_link_id(
        {
            link = handler.link,
            label = handler.label,
            q = handler.q,
            redirect = handler.redirect,
            prefix = handler.prefix,
            id = id,
            separator = handler.separator,
            encode = handler.encode,
            access = access
        }
    )

    if 19 ~= id:len() then
        err_type = cfg.err_msg_supl.length
    else
        year = id:match("^(%d%d%d%d)[%a][%w&%.][%w&%.][%w&%.][%w.]+[%a%.]$")
        if not year then -- if nil then no pattern match
            err_type = cfg.err_msg_supl.value -- so value error
        else
            local next_year = tonumber(os.date("%Y")) + 1 -- get the current year as a number and add one for next year
            year = tonumber(year) -- convert year portion of bibcode to a number
            if (1000 > year) or (year > next_year) then
                err_type = cfg.err_msg_supl.year -- year out of bounds
            end
            if id:find("&%.") then
                err_type = cfg.err_msg_supl.journal -- journal abbreviation must not have '&.' (if it does it's missing a letter)
            end
            if id:match(".........%.tmp%.") then -- temporary bibcodes when positions 10–14 are '.tmp.'
                set_message("maint_bibcode")
            end
        end
    end

    if is_set(err_type) and not ignore_invalid then -- if there was an error detected and accept-as-written markup not used
        set_message("err_bad_bibcode", {err_type})
        options.coins_list_t["BIBCODE"] = nil -- when error, unset so not included in COinS
    end

    return text
end

--[[--------------------------< B I O R X I V >-----------------------------------------------------------------

Format bioRxiv ID and do simple error checking.  Before 2019-12-11, biorXiv IDs were 10.1101/ followed by exactly
6 digits.  After 2019-12-11, biorXiv IDs retained the six-digit identifier but prefixed that with a yyyy.mm.dd. 
date and suffixed with an optional version identifier.

The bioRxiv ID is the string of characters:
	https://doi.org/10.1101/078733 -> 10.1101/078733
or a date followed by a six-digit number followed by an optional version indicator 'v' and one or more digits:
	https://www.biorxiv.org/content/10.1101/2019.12.11.123456v2 -> 10.1101/2019.12.11.123456v2
	
see https://www.biorxiv.org/about-biorxiv

]]
local function biorxiv(options)
    local id = options.id
    local handler = options.handler
    local err_msg = true -- flag; assume that there will be an error

    local patterns = {
        "^10%.1101/%d%d%d%d%d%d$", -- simple 6-digit identifier (before 2019-12-11)
        "^10%.1101/(20%d%d)%.(%d%d)%.(%d%d)%.%d%d%d%d%d%dv%d+$", -- y.m.d. date + 6-digit identifier + version (after 2019-12-11)
        "^10%.1101/(20%d%d)%.(%d%d)%.(%d%d)%.%d%d%d%d%d%d$" -- y.m.d. date + 6-digit identifier (after 2019-12-11)
    }

    for _, pattern in ipairs(patterns) do -- spin through the patterns looking for a match
        if id:match(pattern) then
            local y, m, d = id:match(pattern) -- found a match, attempt to get year, month and date from the identifier

            if m then -- m is nil when id is the six-digit form
                if not is_valid_rxiv_date(y, m, d, "b") then -- validate the encoded date; 'b' for biorxiv limit
                    break -- date fail; break out early so we don't unset the error message
                end
            end
            err_msg = nil -- we found a match so unset the error message
            break -- and done
        end
    end -- err_cat remains set here when no match

    if err_msg then
        options.coins_list_t["BIORXIV"] = nil -- when error, unset so not included in COinS
        set_message("err_bad_biorxiv") -- and set the error message
    end

    return external_link_id(
        {
            link = handler.link,
            label = handler.label,
            q = handler.q,
            redirect = handler.redirect,
            prefix = handler.prefix,
            id = id,
            separator = handler.separator,
            encode = handler.encode,
            access = handler.access
        }
    )
end

--[[--------------------------< C I T E S E E R X >------------------------------------------------------------

CiteSeerX use their own notion of "doi" (not to be confused with the identifiers resolved via doi.org).

The description of the structure of this identifier can be found at Help_talk:Citation_Style_1/Archive_26#CiteSeerX_id_structure

]]
local function citeseerx(options)
    local id = options.id
    local handler = options.handler
    local matched

    local text =
        external_link_id(
        {
            link = handler.link,
            label = handler.label,
            q = handler.q,
            redirect = handler.redirect,
            prefix = handler.prefix,
            id = id,
            separator = handler.separator,
            encode = handler.encode,
            access = handler.access
        }
    )

    matched = id:match("^10%.1%.1%.[1-9]%d?%d?%d?%.[1-9]%d?%d?%d?$")
    if not matched then
        set_message("err_bad_citeseerx")
        options.coins_list_t["CITESEERX"] = nil -- when error, unset so not included in COinS
    end

    return text
end

--[[--------------------------< D O I >------------------------------------------------------------------------

Formats a DOI and checks for DOI errors.

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

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

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

https://www.doi.org/doi_handbook/2_Numbering.html				-- 2.2 Syntax of a DOI name
https://www.doi.org/doi_handbook/2_Numbering.html#2.2.2			-- 2.2.2 DOI prefix

]]
local function doi(options)
    local id = options.id
    local inactive = options.DoiBroken
    local access = options.access
    local ignore_invalid = options.accept
    local handler = options.handler
    local err_flag

    local function is_extended_free(registrant, suffix) -- local function to check those few registrants that are mixed; identifiable by the doi suffix <incipit>
        if cfg.extended_registrants_t[registrant] then -- if this registrant has known free-to-read extentions
            for _, incipit in ipairs(cfg.extended_registrants_t[registrant]) do -- loop through the registrant's incipits
                if mw.ustring.find(suffix, "^" .. incipit) then -- if found
                    return true
                end
            end
        end
    end

    local text
    if is_set(inactive) then
        local inactive_year = inactive:match("%d%d%d%d") -- try to get the year portion from the inactive date
        local inactive_month, good

        if is_set(inactive_year) then
            if 4 < inactive:len() then -- inactive date has more than just a year (could be anything)
                local lang_obj = mw.getContentLanguage() -- get a language object for this wiki
                good, inactive_month = pcall(lang_obj.formatDate, lang_obj, "F", inactive) -- try to get the month name from the inactive date
                if not good then
                    inactive_month = nil -- something went wrong so make sure this is unset
                end
            end
        end -- otherwise, |doi-broken-date= has something but it isn't a date

        if is_set(inactive_year) and is_set(inactive_month) then
            set_message("maint_doi_inactive_dated", {inactive_year, inactive_month, " "})
        elseif is_set(inactive_year) then
            set_message("maint_doi_inactive_dated", {inactive_year, "", ""})
        else
            set_message("maint_doi_inactive")
        end
        inactive = " (" .. cfg.messages["inactive"] .. " " .. inactive .. ")"
    end

    local suffix
    local registrant, suffix = mw.ustring.match(id, "^10%.([^/]+)/([^%s–]-[^%.,])$") -- registrant and suffix set when DOI has the proper basic form

    local registrant_err_patterns = {
        -- these patterns are for code ranges that are not supported
        "^[^1-3]%d%d%d%d%.%d+$", -- 5 digits with subcode (0xxxx, 40000+); accepts: 10000–39999
        "^[^1-7]%d%d%d%d$", -- 5 digits without subcode (0xxxx, 60000+); accepts: 10000–69999
        "^[^1-9]%d%d%d%.%d+$", -- 4 digits with subcode (0xxx); accepts: 1000–9999
        "^[^1-9]%d%d%d$", -- 4 digits without subcode (0xxx); accepts: 1000–9999
        "^%d%d%d%d%d%d+", -- 6 or more digits
        "^%d%d?%d?$", -- less than 4 digits without subcode (3 digits with subcode is legitimate)
        "^%d%d?%.[%d%.]+", -- 1 or 2 digits with subcode
        "^5555$", -- test registrant will never resolve
        "[^%d%.]" -- any character that isn't a digit or a dot
    }

    if not ignore_invalid then
        if registrant then -- when DOI has proper form
            for i, pattern in ipairs(registrant_err_patterns) do -- spin through error patterns
                if registrant:match(pattern) then -- to validate registrant codes
                    err_flag = set_message("err_bad_doi") -- when found, mark this DOI as bad
                    break -- and done
                end
            end
        else
            err_flag = set_message("err_bad_doi") -- invalid directory or malformed
        end
    else
        set_message("maint_doi_ignore")
    end

    if err_flag then
        options.coins_list_t["DOI"] = nil -- when error, unset so not included in COinS
    else
        if not access and (cfg.known_free_doi_registrants_t[registrant] or is_extended_free(registrant, suffix)) then -- |doi-access=free not set and <registrant> is known to be free
            set_message("maint_doi_unflagged_free") -- set a maint cat
        end
    end

    text =
        external_link_id(
        {
            link = handler.link,
            label = handler.label,
            q = handler.q,
            redirect = handler.redirect,
            prefix = handler.prefix,
            id = id,
            separator = handler.separator,
            encode = handler.encode,
            access = access,
            auto_link = not (err_flag or is_set(inactive) or ignore_invalid) and "doi" or nil -- do not auto-link when |doi-broken-date= has a value or when there is a DOI error or (to play it safe, after all, auto-linking is not essential) when invalid DOIs are ignored
        }
    ) .. (inactive or "")

    return text
end

--[[--------------------------< H D L >------------------------------------------------------------------------

Formats an HDL with minor error checking.

HDL names contain two parts: prefix and suffix separated by a forward slash.
	Prefix: character string using any character in the UCS-2 character set except '/'
	Suffix: character string of any length using any character in the UCS-2 character set chosen by the registrant

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

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

Query string parameters are named here: https://www.handle.net/proxy_servlet.html.  query strings are not displayed
but since '?' is an allowed character in an HDL, '?' followed by one of the query parameters is the only way we
have to detect the query string so that it isn't URL-encoded with the rest of the identifier.

]]
local function hdl(options)
    local id = options.id
    local access = options.access
    local handler = options.handler
    local query_params = {
        -- list of known query parameters from https://www.handle.net/proxy_servlet.html
        "noredirect",
        "ignore_aliases",
        "auth",
        "cert",
        "index",
        "type",
        "urlappend",
        "locatt",
        "action"
    }

    local hdl, suffix, param = id:match("(.-)(%?(%a+).+)$") -- look for query string
    local found

    if hdl then -- when there are query strings, this is the handle identifier portion
        for _, q in ipairs(query_params) do -- spin through the list of query parameters
            if param:match("^" .. q) then -- if the query string begins with one of the parameters
                found = true -- announce a find
                break -- and stop looking
            end
        end
    end

    if found then
        id = hdl -- found so replace id with the handle portion; this will be URL-encoded, suffix will not
    else
        suffix = "" -- make sure suffix is empty string for concatenation else
    end

    local text =
        external_link_id(
        {
            link = handler.link,
            label = handler.label,
            q = handler.q,
            redirect = handler.redirect,
            prefix = handler.prefix,
            id = id,
            suffix = suffix,
            separator = handler.separator,
            encode = handler.encode,
            access = access
        }
    )

    if nil == id:match("^[^%s–]-/[^%s–]-[^%.,]$") then -- HDL must contain a forward slash, must not contain spaces, endashes, and must not end with period or comma
        set_message("err_bad_hdl")
        options.coins_list_t["HDL"] = nil -- when error, unset so not included in COinS
    end

    return text
end

--[[--------------------------< I S B N >----------------------------------------------------------------------

Determines whether an ISBN string is valid

]]
local function isbn(options_t)
    local isbn_str = options_t.id
    local ignore_invalid = options_t.accept
    local handler = options_t.handler
    local year = options_t.Year -- when set, valid anchor_year; may have a disambiguator which must be removed

    local function return_result(check, err_type) -- local function to handle the various returns
        local ISBN =
            internal_link_id(
            {
                link = handler.link,
                label = handler.label,
                redirect = handler.redirect,
                prefix = handler.prefix,
                id = isbn_str,
                separator = handler.separator
            }
        )
        if ignore_invalid then -- if ignoring ISBN errors
            set_message("maint_isbn_ignore") -- add a maint category even when there is no error
        else -- here when not ignoring
            if not check then -- and there is an error
                options_t.coins_list_t["ISBN"] = nil -- when error, unset so not included in COinS
                set_message("err_bad_isbn", err_type) -- set an error message
                return ISBN -- return id text
            end
        end
        return ISBN -- return id text
    end

    if year and not ignore_invalid then --
        year = year:match("%d%d%d%d?") -- strip disambiguator if present
        if year and (1965 > tonumber(year)) then -- <year> will be nil here when |year=n.d. or |year=nd
            set_message("err_invalid_isbn_date") -- set an error message
            return internal_link_id(
                {
                    link = handler.link,
                    label = handler.label,
                    redirect = handler.redirect,
                    prefix = handler.prefix,
                    id = isbn_str,
                    separator = handler.separator
                }
            )
        end
    end

    if nil ~= isbn_str:match("[^%s-0-9X]") then
        return return_result(false, cfg.err_msg_supl.char) -- fail if isbn_str contains anything but digits, hyphens, or the uppercase X
    end

    local id = isbn_str:gsub("[%s-]", "") -- remove hyphens and whitespace

    local len = id:len()

    if len ~= 10 and len ~= 13 then
        return return_result(false, cfg.err_msg_supl.length) -- fail if incorrect length
    end

    if len == 10 then
        if id:match("^%d*X?$") == nil then -- fail if isbn_str has 'X' anywhere but last position
            return return_result(false, cfg.err_msg_supl.form)
        end
        if not is_valid_isxn(id, 10) then -- test isbn-10 for numerical validity
            return return_result(false, cfg.err_msg_supl.check) -- fail if isbn-10 is not numerically valid
        end
        if id:find("^63[01]") then -- 630xxxxxxx and 631xxxxxxx are (apparently) not valid isbn group ids but are used by amazon as numeric identifiers (asin)
            return return_result(false, cfg.err_msg_supl.group) -- fail if isbn-10 begins with 630/1
        end
        return return_result(true, cfg.err_msg_supl.check) -- pass if isbn-10 is numerically valid
    else
        if id:match("^%d+$") == nil then
            return return_result(false, cfg.err_msg_supl.char) -- fail if ISBN-13 is not all digits
        end
        if id:match("^97[89]%d*$") == nil then
            return return_result(false, cfg.err_msg_supl.prefix) -- fail when ISBN-13 does not begin with 978 or 979
        end
        if id:match("^9790") then
            return return_result(false, cfg.err_msg_supl.group) -- group identifier '0' is reserved to ISMN
        end
        return return_result(is_valid_isxn_13(id), cfg.err_msg_supl.check)
    end
end

--[[--------------------------< A S I N >----------------------------------------------------------------------

Formats a link to Amazon.  Do simple error checking: ASIN must be mix of 10 numeric or uppercase alpha
characters.  If a mix, first character must be uppercase alpha; if all numeric, ASINs must be 10-digit
ISBN. If 10-digit ISBN, add a maintenance category so a bot or AWB script can replace |asin= with |isbn=.
Error message if not 10 characters, if not ISBN-10, if mixed and first character is a digit.

|asin=630....... and |asin=631....... are (apparently) not a legitimate ISBN though it checksums as one; these
do not cause this function to emit the maint_asin message

This function is positioned here because it calls isbn()

]]
local function asin(options)
    local id = options.id
    local domain = options.ASINTLD

    local err_flag

    if not id:match("^[%d%u][%d%u][%d%u][%d%u][%d%u][%d%u][%d%u][%d%u][%d%u][%d%u]$") then
        err_flag = set_message("err_bad_asin") -- ASIN is not a mix of 10 uppercase alpha and numeric characters
    else
        if id:match("^%d%d%d%d%d%d%d%d%d[%dX]$") then -- if 10-digit numeric (or 9 digits with terminal X)
            if is_valid_isxn(id, 10) then -- see if ASIN value is or validates as ISBN-10
                if not id:find("^63[01]") then -- 630xxxxxxx and 631xxxxxxx are (apparently) not a valid isbn prefixes but are used by amazon as a numeric identifier
                    err_flag = set_message("err_bad_asin") -- ASIN has ISBN-10 form but begins with something other than 630/1 so probably an isbn
                end
            elseif not is_set(err_flag) then
                err_flag = set_message("err_bad_asin") -- ASIN is not ISBN-10
            end
        elseif not id:match("^%u[%d%u]+$") then
            err_flag = set_message("err_bad_asin") -- asin doesn't begin with uppercase alpha
        end
    end
    if (not is_set(domain)) or in_array(domain, {"us"}) then -- default: United States
        domain = "com"
    elseif in_array(domain, {"jp", "uk"}) then -- Japan, United Kingdom
        domain = "co." .. domain
    elseif in_array(domain, {"z.cn"}) then -- China
        domain = "cn"
    elseif in_array(domain, {"au", "br", "mx", "sg", "tr"}) then -- Australia, Brazil, Mexico, Singapore, Turkey
        domain = "com." .. domain
    elseif
        not in_array(
            domain,
            {
                "ae",
                "ca",
                "cn",
                "de",
                "es",
                "fr",
                "in",
                "it",
                "nl",
                "pl",
                "sa",
                "se",
                "co.jp",
                "co.uk",
                "com",
                "com.au",
                "com.br",
                "com.mx",
                "com.sg",
                "com.tr"
            }
        )
     then -- Arabic Emirates, Canada, China, Germany, Spain, France, Indonesia, Italy, Netherlands, Poland, Saudi Arabia, Sweden (as of 2021-03 Austria (.at), Liechtenstein (.li) and Switzerland (.ch) still redirect to the German site (.de) with special settings, so don't maintain local ASINs for them)
        err_flag = set_message("err_bad_asin_tld") -- unsupported asin-tld value
    end
    local handler = options.handler

    if not is_set(err_flag) then
        options.coins_list_t["ASIN"] = handler.prefix .. domain .. "/dp/" .. id -- asin for coins
    else
        options.coins_list_t["ASIN"] = nil -- when error, unset so not included in COinS
    end

    return external_link_id(
        {
            link = handler.link,
            label = handler.label,
            q = handler.q,
            redirect = handler.redirect,
            prefix = handler.prefix .. domain .. "/dp/",
            id = id,
            encode = handler.encode,
            separator = handler.separator
        }
    )
end

--[[--------------------------< I S M N >----------------------------------------------------------------------

Determines whether an ISMN string is valid.  Similar to ISBN-13, ISMN is 13 digits beginning 979-0-... and uses the
same check digit calculations.  See https://www.ismn-international.org/download/Web_ISMN_Users_Manual_2008-6.pdf
section 2, pages 9–12.

ismn value not made part of COinS metadata because we don't have a url or isn't a COinS-defined identifier (rft.xxx)
or an identifier registered at info-uri.info (info:)

]]
local function ismn(options)
    local id = options.id
    local handler = options.handler
    local text
    local valid_ismn = true
    local id_copy

    id_copy = id -- save a copy because this testing is destructive
    id = id:gsub("[%s-]", "") -- remove hyphens and white space

    if 13 ~= id:len() or id:match("^9790%d*$") == nil then -- ISMN must be 13 digits and begin with 9790
        valid_ismn = false
    else
        valid_ismn = is_valid_isxn_13(id) -- validate ISMN
    end

    --	text = internal_link_id ({link = handler.link, label = handler.label, q = handler.q, redirect = handler.redirect,		-- use this (or external version) when there is some place to link to
    --		prefix = handler.prefix, id = id_copy, separator = handler.separator, encode = handler.encode})

    text =
        table.concat( -- because no place to link to yet
        {
            make_wikilink(label_link_make(handler), handler.label),
            handler.separator,
            id_copy
        }
    )

    if false == valid_ismn then
        options.coins_list_t["ISMN"] = nil -- when error, unset so not included in COinS; not really necessary here because ismn not made part of COinS
        set_message("err_bad_ismn") -- create an error message if the ISMN is invalid
    end

    return text
end

--[[--------------------------< I S S N >----------------------------------------------------------------------

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

	|issn=0819 4327 gives: [https://www.worldcat.org/issn/0819 4327 0819 4327]	-- can't have spaces in an external link
	
This code now prevents that by inserting a hyphen at the ISSN midpoint.  It also validates the ISSN for length
and makes sure that the checkdigit agrees with the calculated value.  Incorrect length (8 digits), characters
other than 0-9 and X, or checkdigit / calculated value mismatch will all cause a check ISSN error message.  The
ISSN is always displayed with a hyphen, even if the ISSN was given as a single group of 8 digits.

]]
local function issn(options)
    local id = options.id
    local handler = options.handler
    local ignore_invalid = options.accept

    local issn_copy = id -- save a copy of unadulterated ISSN; use this version for display if ISSN does not validate
    local text
    local valid_issn = true

    id = id:gsub("[%s-]", "") -- remove hyphens and whitespace

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

    if true == valid_issn then
        id = string.sub(id, 1, 4) .. "-" .. string.sub(id, 5) -- if valid, display correctly formatted version
    else
        id = issn_copy -- if not valid, show the invalid ISSN with error message
    end

    text =
        external_link_id(
        {
            link = handler.link,
            label = handler.label,
            q = handler.q,
            redirect = handler.redirect,
            prefix = handler.prefix,
            id = id,
            separator = handler.separator,
            encode = handler.encode
        }
    )

    if ignore_invalid then
        set_message("maint_issn_ignore")
    else
        if false == valid_issn then
            options.coins_list_t["ISSN"] = nil -- when error, unset so not included in COinS
            set_message("err_bad_issn", (options.hkey == "EISSN") and "e" or "") -- create an error message if the ISSN is invalid
        end
    end

    return text
end

--[[--------------------------< J F M >-----------------------------------------------------------------------

A numerical identifier in the form nn.nnnn.nn

]]
local function jfm(options)
    local id = options.id
    local handler = options.handler
    local id_num

    id_num = id:match("^[Jj][Ff][Mm](.*)$") -- identifier with jfm prefix; extract identifier

    if is_set(id_num) then
        set_message("maint_jfm_format")
    else -- plain number without JFM prefix
        id_num = id -- if here id does not have prefix
    end

    if id_num and id_num:match("^%d%d%.%d%d%d%d%.%d%d$") then
        id = id_num -- jfm matches pattern
    else
        set_message("err_bad_jfm") -- set an error message
        options.coins_list_t["JFM"] = nil -- when error, unset so not included in COinS
    end

    return external_link_id(
        {
            link = handler.link,
            label = handler.label,
            q = handler.q,
            redirect = handler.redirect,
            prefix = handler.prefix,
            id = id,
            separator = handler.separator,
            encode = handler.encode
        }
    )
end

--[[--------------------------< J S T O R >--------------------------------------------------------------------

Format a JSTOR with some error checking

]]
local function jstor(options)
    local id = options.id
    local access = options.access
    local handler = options.handler

    if id:find("[Jj][Ss][Tt][Oo][Rr]") or id:find("^https?://") or id:find("%s") then
        set_message("err_bad_jstor") -- set an error message
        options.coins_list_t["JSTOR"] = nil -- when error, unset so not included in COinS
    end

    return external_link_id(
        {
            link = handler.link,
            label = handler.label,
            q = handler.q,
            redirect = handler.redirect,
            prefix = handler.prefix,
            id = id,
            separator = handler.separator,
            encode = handler.encode,
            access = access
        }
    )
end

--[[--------------------------< L C C N >----------------------------------------------------------------------

Format LCCN link and do simple error checking.  LCCN is a character string 8-12 characters long. The length of
the LCCN dictates the character type of the first 1-3 characters; the rightmost eight are always digits.
https://oclc-research.github.io/infoURI-Frozen/info-uri.info/info:lccn/reg.html

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

]]
local function lccn(options)
    local lccn = options.id
    local handler = options.handler
    local err_flag  -- presume that LCCN is valid
    local id = lccn -- local copy of the LCCN

    id = normalize_lccn(id) -- get canonical form (no whitespace, hyphens, forward slashes)
    local len = id:len() -- get the length of the LCCN

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

    if not is_set(err_flag) and nil ~= lccn:find("%s") then
        err_flag = set_message("err_bad_lccn") -- lccn contains a space, set an error message
    end

    if is_set(err_flag) then
        options.coins_list_t["LCCN"] = nil -- when error, unset so not included in COinS
    end

    return external_link_id(
        {
            link = handler.link,
            label = handler.label,
            q = handler.q,
            redirect = handler.redirect,
            prefix = handler.prefix,
            id = lccn,
            separator = handler.separator,
            encode = handler.encode
        }
    )
end

--[[--------------------------< M E D R X I V >-----------------------------------------------------------------

Format medRxiv ID and do simple error checking.  Similar to later bioRxiv IDs, medRxiv IDs are prefixed with a
yyyy.mm.dd. date and suffixed with an optional version identifier.  Ealiest date accepted is 2020.01.01

The medRxiv ID is a date followed by an eight-digit number followed by an optional version indicator 'v' and one or more digits:
	https://www.medrxiv.org/content/10.1101/2020.11.16.20232009v2 -> 10.1101/2020.11.16.20232009v2

]]
local function medrxiv(options)
    local id = options.id
    local handler = options.handler
    local err_msg_flag = true -- flag; assume that there will be an error

    local patterns = {
        "^%d%d%d%d%d%d%d%d$", -- simple 8-digit identifier; these should be relatively rare
        "^10%.1101/(20%d%d)%.(%d%d)%.(%d%d)%.%d%d%d%d%d%d%d%dv%d+$", -- y.m.d. date + 8-digit identifier + version (2020-01-01 and later)
        "^10%.1101/(20%d%d)%.(%d%d)%.(%d%d)%.%d%d%d%d%d%d%d%d$" -- y.m.d. date + 8-digit identifier (2020-01-01 and later)
    }

    for _, pattern in ipairs(patterns) do -- spin through the patterns looking for a match
        if id:match(pattern) then
            local y, m, d = id:match(pattern) -- found a match, attempt to get year, month and date from the identifier

            if m then -- m is nil when id is the 8-digit form
                if not is_valid_rxiv_date(y, m, d, "b") then -- validate the encoded date; 'b' for medrxiv limit
                    break -- date fail; break out early so we don't unset the error message
                end
            end
            err_msg_flag = nil -- we found a match so unset the error message
            break -- and done
        end
    end -- <err_msg_flag> remains set here when no match

    if err_msg_flag then
        options.coins_list_t["MEDRXIV"] = nil -- when error, unset so not included in COinS
        set_message("err_bad_medrxiv") -- and set the error message
    end

    return external_link_id(
        {
            link = handler.link,
            label = handler.label,
            q = handler.q,
            redirect = handler.redirect,
            prefix = handler.prefix,
            id = id,
            separator = handler.separator,
            encode = handler.encode,
            access = handler.access
        }
    )
end

--[[--------------------------< M R >--------------------------------------------------------------------------

A seven digit number; if not seven digits, zero-fill leading digits to make seven digits.

]]
local function mr(options)
    local id = options.id
    local handler = options.handler
    local id_num
    local id_len

    id_num = id:match("^[Mm][Rr](%d+)$") -- identifier with mr prefix

    if is_set(id_num) then
        set_message("maint_mr_format") -- add maint cat
    else -- plain number without mr prefix
        id_num = id:match("^%d+$") -- if here id is all digits
    end

    id_len = id_num and id_num:len() or 0
    if (7 >= id_len) and (0 ~= id_len) then
        id = string.rep("0", 7 - id_len) .. id_num -- zero-fill leading digits
    else
        set_message("err_bad_mr") -- set an error message
        options.coins_list_t["MR"] = nil -- when error, unset so not included in COinS
    end

    return external_link_id(
        {
            link = handler.link,
            label = handler.label,
            q = handler.q,
            redirect = handler.redirect,
            prefix = handler.prefix,
            id = id,
            separator = handler.separator,
            encode = handler.encode
        }
    )
end

--[[--------------------------< O C L C >----------------------------------------------------------------------

Validate and format an OCLC ID.  https://www.oclc.org/batchload/controlnumber.en.html {{dead link}}
archived at: https://web.archive.org/web/20161228233804/https://www.oclc.org/batchload/controlnumber.en.html

]]
local function oclc(options)
    local id = options.id
    local handler = options.handler
    local number

    if id:match("^ocm%d%d%d%d%d%d%d%d$") then -- ocm prefix and 8 digits; 001 field (12 characters)
        number = id:match("ocm(%d+)") -- get the number
    elseif id:match("^ocn%d%d%d%d%d%d%d%d%d$") then -- ocn prefix and 9 digits; 001 field (12 characters)
        number = id:match("ocn(%d+)") -- get the number
    elseif id:match("^on%d%d%d%d%d%d%d%d%d%d+$") then -- on prefix and 10 or more digits; 001 field (12 characters)
        number = id:match("^on(%d%d%d%d%d%d%d%d%d%d+)$") -- get the number
    elseif id:match("^%(OCoLC%)[1-9]%d*$") then -- (OCoLC) prefix and variable number digits; no leading zeros; 035 field
        number = id:match("%(OCoLC%)([1-9]%d*)") -- get the number
        if 9 < number:len() then
            number = nil -- constrain to 1 to 9 digits; change this when OCLC issues 10-digit numbers
        end
    elseif id:match("^%d+$") then -- no prefix
        number = id -- get the number
        if tonumber(id) > handler.id_limit then
            number = nil -- unset when id value exceeds the limit
        end
    end

    if number then -- proper format
        id = number -- exclude prefix, if any, from external link
    else
        set_message("err_bad_oclc") -- add an error message if the id is malformed
        options.coins_list_t["OCLC"] = nil -- when error, unset so not included in COinS
    end

    return external_link_id(
        {
            link = handler.link,
            label = handler.label,
            q = handler.q,
            redirect = handler.redirect,
            prefix = handler.prefix,
            id = id,
            separator = handler.separator,
            encode = handler.encode
        }
    )
end

--[[--------------------------< O P E N L I B R A R Y >--------------------------------------------------------

Formats an OpenLibrary link, and checks for associated errors.

]]
local function openlibrary(options)
    local id = options.id
    local access = options.access
    local handler = options.handler
    local ident, code = id:gsub("^OL", ""):match("^(%d+([AMW]))$") -- strip optional OL prefix followed immediately by digits followed by 'A', 'M', or 'W';
    local err_flag
    local prefix = {
        -- these are appended to the handler.prefix according to code
        ["A"] = "authors/OL",
        ["M"] = "books/OL",
        ["W"] = "works/OL",
        ["X"] = "OL" -- not a code; spoof when 'code' in id is invalid
    }

    if not ident then
        code = "X" -- no code or id completely invalid
        ident = id -- copy id to ident so that we display the flawed identifier
        err_flag = set_message("err_bad_ol")
    end

    if not is_set(err_flag) then
        options.coins_list_t["OL"] = handler.prefix .. prefix[code] .. ident -- experiment for ol coins
    else
        options.coins_list_t["OL"] = nil -- when error, unset so not included in COinS
    end

    return external_link_id(
        {
            link = handler.link,
            label = handler.label,
            q = handler.q,
            redirect = handler.redirect,
            prefix = handler.prefix .. prefix[code],
            id = ident,
            separator = handler.separator,
            encode = handler.encode,
            access = access
        }
    )
end

--[[--------------------------< O S T I >----------------------------------------------------------------------

Format OSTI and do simple error checking. OSTIs are sequential numbers beginning at 1 and counting up.  This
code checks the OSTI to see that it contains only digits and is less than test_limit specified in the configuration;
the value in test_limit will need to be updated periodically as more OSTIs are issued.

NB. 1018 is the lowest OSTI number found in the wild (so far) and resolving OK on the OSTI site

]]
local function osti(options)
    local id = options.id
    local access = options.access
    local handler = options.handler

    if id:match("[^%d]") then -- if OSTI has anything but digits
        set_message("err_bad_osti") -- set an error message
        options.coins_list_t["OSTI"] = nil -- when error, unset so not included in COinS
    else -- OSTI is only digits
        local id_num = tonumber(id) -- convert id to a number for range testing
        if 1018 > id_num or handler.id_limit < id_num then -- if OSTI is outside test limit boundaries
            set_message("err_bad_osti") -- set an error message
            options.coins_list_t["OSTI"] = nil -- when error, unset so not included in COinS
        end
    end

    return external_link_id(
        {
            link = handler.link,
            label = handler.label,
            q = handler.q,
            redirect = handler.redirect,
            prefix = handler.prefix,
            id = id,
            separator = handler.separator,
            encode = handler.encode,
            access = access
        }
    )
end

--[[--------------------------< P M C >------------------------------------------------------------------------

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

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

PMC embargo date testing is done in function is_embargoed () which is called earlier because when the citation
has |pmc=<value> but does not have a |url= then |title= is linked with the PMC link.  Function is_embargoed ()
returns the embargo date if the PMC article is still embargoed, otherwise it returns an empty string.

PMCs are sequential numbers beginning at 1 and counting up.  This code checks the PMC to see that it contains only digits and is less
than test_limit; the value in local variable test_limit will need to be updated periodically as more PMCs are issued.

]]
local function pmc(options)
    local id = options.id
    local embargo = options.Embargo -- TODO: lowercase?
    local handler = options.handler
    local err_flag
    local id_num
    local text

    id_num = id:match("^[Pp][Mm][Cc](%d+)$") -- identifier with PMC prefix

    if is_set(id_num) then
        set_message("maint_pmc_format")
    else -- plain number without PMC prefix
        id_num = id:match("^%d+$") -- if here id is all digits
    end

    if is_set(id_num) then -- id_num has a value so test it
        id_num = tonumber(id_num) -- convert id_num to a number for range testing
        if 1 > id_num or handler.id_limit < id_num then -- if PMC is outside test limit boundaries
            err_flag = set_message("err_bad_pmc") -- set an error message
        else
            id = tostring(id_num) -- make sure id is a string
        end
    else -- when id format incorrect
        err_flag = set_message("err_bad_pmc") -- set an error message
    end

    if is_set(embargo) and is_set(is_embargoed(embargo)) then -- is PMC is still embargoed?
        text =
            table.concat( -- still embargoed so no external link
            {
                make_wikilink(label_link_make(handler), handler.label),
                handler.separator,
                id
            }
        )
    else
        text =
            external_link_id(
            {
                link = handler.link,
                label = handler.label,
                q = handler.q,
                redirect = handler.redirect, -- no embargo date or embargo has expired, ok to link to article
                prefix = handler.prefix,
                id = id,
                separator = handler.separator,
                encode = handler.encode,
                access = handler.access,
                auto_link = not err_flag and "pmc" or nil -- do not auto-link when PMC has error
            }
        )
    end

    if err_flag then
        options.coins_list_t["PMC"] = nil -- when error, unset so not included in COinS
    end

    return text
end

--[[--------------------------< P M I D >----------------------------------------------------------------------

Format PMID and do simple error checking.  PMIDs are sequential numbers beginning at 1 and counting up.  This
code checks the PMID to see that it contains only digits and is less than test_limit; the value in local variable
test_limit will need to be updated periodically as more PMIDs are issued.

]]
local function pmid(options)
    local id = options.id
    local handler = options.handler

    if id:match("[^%d]") then -- if PMID has anything but digits
        set_message("err_bad_pmid") -- set an error message
        options.coins_list_t["PMID"] = nil -- when error, unset so not included in COinS
    else -- PMID is only digits
        local id_num = tonumber(id) -- convert id to a number for range testing
        if 1 > id_num or handler.id_limit < id_num then -- if PMID is outside test limit boundaries
            set_message("err_bad_pmid") -- set an error message
            options.coins_list_t["PMID"] = nil -- when error, unset so not included in COinS
        end
    end

    return external_link_id(
        {
            link = handler.link,
            label = handler.label,
            q = handler.q,
            redirect = handler.redirect,
            prefix = handler.prefix,
            id = id,
            separator = handler.separator,
            encode = handler.encode
        }
    )
end

--[[--------------------------< R F C >------------------------------------------------------------------------

Format RFC and do simple error checking. RFCs are sequential numbers beginning at 1 and counting up.  This
code checks the RFC to see that it contains only digits and is less than test_limit specified in the configuration;
the value in test_limit will need to be updated periodically as more RFCs are issued.

An index of all RFCs is here: https://tools.ietf.org/rfc/

]]
local function rfc(options)
    local id = options.id
    local handler = options.handler

    if id:match("[^%d]") then -- if RFC has anything but digits
        set_message("err_bad_rfc") -- set an error message
        options.coins_list_t["RFC"] = nil -- when error, unset so not included in COinS
    else -- RFC is only digits
        local id_num = tonumber(id) -- convert id to a number for range testing
        if 1 > id_num or handler.id_limit < id_num then -- if RFC is outside test limit boundaries
            set_message("err_bad_rfc") -- set an error message
            options.coins_list_t["RFC"] = nil -- when error, unset so not included in COinS
        end
    end

    return external_link_id(
        {
            link = handler.link,
            label = handler.label,
            q = handler.q,
            redirect = handler.redirect,
            prefix = handler.prefix,
            id = id,
            separator = handler.separator,
            encode = handler.encode,
            access = handler.access
        }
    )
end

--[[--------------------------< S 2 C I D >--------------------------------------------------------------------

Format an S2CID, do simple error checking

S2CIDs are sequential numbers beginning at 1 and counting up.  This code checks the S2CID to see that it is only
digits and is less than test_limit; the value in local variable test_limit will need to be updated periodically
as more S2CIDs are issued.

]]
local function s2cid(options)
    local id = options.id
    local access = options.access
    local handler = options.handler
    local id_num
    local text

    id_num = id:match("^[1-9]%d*$") -- id must be all digits; must not begin with 0; no open access flag

    if is_set(id_num) then -- id_num has a value so test it
        id_num = tonumber(id_num) -- convert id_num to a number for range testing
        if handler.id_limit < id_num then -- if S2CID is outside test limit boundaries
            set_message("err_bad_s2cid") -- set an error message
            options.coins_list_t["S2CID"] = nil -- when error, unset so not included in COinS
        end
    else -- when id format incorrect
        set_message("err_bad_s2cid") -- set an error message
        options.coins_list_t["S2CID"] = nil -- when error, unset so not included in COinS
    end

    text =
        external_link_id(
        {
            link = handler.link,
            label = handler.label,
            q = handler.q,
            redirect = handler.redirect,
            prefix = handler.prefix,
            id = id,
            separator = handler.separator,
            encode = handler.encode,
            access = access
        }
    )

    return text
end

--[[--------------------------< S B N >------------------------------------------------------------------------

9-digit form of ISBN-10; uses same check-digit validation when SBN is prefixed with an additional '0' to make 10 digits

sbn value not made part of COinS metadata because we don't have a url or isn't a COinS-defined identifier (rft.xxx)
or an identifier registered at info-uri.info (info:)

]]
local function sbn(options)
    local id = options.id
    local ignore_invalid = options.accept
    local handler = options.handler
    local function return_result(check, err_type) -- local function to handle the various returns
        local SBN =
            internal_link_id(
            {
                link = handler.link,
                label = handler.label,
                redirect = handler.redirect,
                prefix = handler.prefix,
                id = id,
                separator = handler.separator
            }
        )
        if not ignore_invalid then -- if not ignoring SBN errors
            if not check then
                options.coins_list_t["SBN"] = nil -- when error, unset so not included in COinS; not really necessary here because sbn not made part of COinS
                set_message("err_bad_sbn", {err_type}) -- display an error message
                return SBN
            end
        else
            set_message("maint_isbn_ignore") -- add a maint category even when there is no error (ToDo: Possibly switch to separate message for SBNs only)
        end
        return SBN
    end

    if id:match("[^%s-0-9X]") then
        return return_result(false, cfg.err_msg_supl.char) -- fail if SBN contains anything but digits, hyphens, or the uppercase X
    end

    local ident = id:gsub("[%s-]", "") -- remove hyphens and whitespace; they interfere with the rest of the tests

    if 9 ~= ident:len() then
        return return_result(false, cfg.err_msg_supl.length) -- fail if incorrect length
    end

    if ident:match("^%d*X?$") == nil then
        return return_result(false, cfg.err_msg_supl.form) -- fail if SBN has 'X' anywhere but last position
    end

    return return_result(is_valid_isxn("0" .. ident, 10), cfg.err_msg_supl.check)
end

--[[--------------------------< S S R N >----------------------------------------------------------------------

Format an SSRN, do simple error checking

SSRNs are sequential numbers beginning at 100? and counting up.  This code checks the SSRN to see that it is
only digits and is greater than 99 and less than test_limit; the value in local variable test_limit will need
to be updated periodically as more SSRNs are issued.

]]
local function ssrn(options)
    local id = options.id
    local handler = options.handler
    local id_num
    local text

    id_num = id:match("^%d+$") -- id must be all digits

    if is_set(id_num) then -- id_num has a value so test it
        id_num = tonumber(id_num) -- convert id_num to a number for range testing
        if 100 > id_num or handler.id_limit < id_num then -- if SSRN is outside test limit boundaries
            set_message("err_bad_ssrn") -- set an error message
            options.coins_list_t["SSRN"] = nil -- when error, unset so not included in COinS
        end
    else -- when id format incorrect
        set_message("err_bad_ssrn") -- set an error message
        options.coins_list_t["SSRN"] = nil -- when error, unset so not included in COinS
    end

    text =
        external_link_id(
        {
            link = handler.link,
            label = handler.label,
            q = handler.q,
            redirect = handler.redirect,
            prefix = handler.prefix,
            id = id,
            separator = handler.separator,
            encode = handler.encode,
            access = options.access
        }
    )

    return text
end

--[[--------------------------< U S E N E T _ I D >------------------------------------------------------------

Validate and format a usenet message id.  Simple error checking, looks for 'id-left@id-right' not enclosed in
'<' and/or '>' angle brackets.

]]
local function usenet_id(options)
    local id = options.id
    local handler = options.handler

    local text =
        external_link_id(
        {
            link = handler.link,
            label = handler.label,
            q = handler.q,
            redirect = handler.redirect,
            prefix = handler.prefix,
            id = id,
            separator = handler.separator,
            encode = handler.encode
        }
    )

    if not id:match("^.+@.+$") or not id:match("^[^<].*[^>]$") then -- doesn't have '@' or has one or first or last character is '< or '>'
        set_message("err_bad_usenet_id") -- add an error message if the message id is invalid
        options.coins_list_t["USENETID"] = nil -- when error, unset so not included in COinS
    end

    return text
end

--[[--------------------------< Z B L >-----------------------------------------------------------------------

A numerical identifier in the form nnnn.nnnnn - leading zeros in the first quartet optional

format described here: http://emis.mi.sanu.ac.rs/ZMATH/zmath/en/help/search/

temporary format is apparently eight digits.  Anything else is an error

]]
local function zbl(options)
    local id = options.id
    local handler = options.handler

    if id:match("^%d%d%d%d%d%d%d%d$") then -- is this identifier using temporary format?
        set_message("maint_zbl") -- yes, add maint cat
    elseif not id:match("^%d?%d?%d?%d%.%d%d%d%d%d$") then -- not temporary, is it normal format?
        set_message("err_bad_zbl") -- no, set an error message
        options.coins_list_t["ZBL"] = nil -- when error, unset so not included in COinS
    end

    return external_link_id(
        {
            link = handler.link,
            label = handler.label,
            q = handler.q,
            redirect = handler.redirect,
            prefix = handler.prefix,
            id = id,
            separator = handler.separator,
            encode = handler.encode
        }
    )
end

--============================<< I N T E R F A C E   F U N C T I O N S >>==========================================

--[[--------------------------< E X T R A C T _ I D S >------------------------------------------------------------

Populates ID table from arguments using configuration settings. Loops through cfg.id_handlers and searches args for
any of the parameters listed in each cfg.id_handlers['...'].parameters.  If found, adds the parameter and value to
the identifier list.  Emits redundant error message if more than one alias exists in args

]]
local function extract_ids(args)
    local id_list = {} -- list of identifiers found in args
    for k, v in pairs(cfg.id_handlers) do -- k is uppercase identifier name as index to cfg.id_handlers; e.g. cfg.id_handlers['ISBN'], v is a table
        v = select_one(args, v.parameters, "err_redundant_parameters") -- v.parameters is a table of aliases for k; here we pick one from args if present
        if is_set(v) then
            id_list[k] = v
        end -- if found in args, add identifier to our list
    end
    return id_list
end

--[[--------------------------< E X T R A C T _ I D _ A C C E S S _ L E V E L S >--------------------------------------

Fetches custom id access levels from arguments using configuration settings. Parameters which have a predefined access
level (e.g. arxiv) do not use this function as they are directly rendered as free without using an additional parameter.

returns a table of k/v pairs where k is same as the identifier's key in cfg.id_handlers and v is the assigned (valid) keyword

access-level values must match the case used in cfg.keywords_lists['id-access'] (lowercase unless there is some special reason for something else)

]]
local function extract_id_access_levels(args, id_list)
    local id_accesses_list = {}
    for k, v in pairs(cfg.id_handlers) do
        local access_param = v.custom_access -- name of identifier's access-level parameter
        if is_set(access_param) then
            local access_level = args[access_param] -- get the assigned value if there is one
            if is_set(access_level) then
                if not in_array(access_level, cfg.keywords_lists["id-access"]) then -- exact match required
                    set_message("err_invalid_param_val", {access_param, access_level})
                    access_level = nil -- invalid so unset
                end
                if not is_set(id_list[k]) then -- identifier access-level must have a matching identifier
                    set_message("err_param_access_requires_param", {k:lower()}) -- parameter name is uppercase in cfg.id_handlers (k); lowercase for error message
                end
                id_accesses_list[k] = cfg.keywords_xlate[access_level] -- get translated keyword
            end
        end
    end
    return id_accesses_list
end

--[[--------------------------< B U I L D _ I D _ L I S T >----------------------------------------------------

render the identifiers into a sorted sequence table

<ID_list_coins_t> is a table of k/v pairs where k is same as key in cfg.id_handlers and v is the assigned value
<options_t> is a table of various k/v option pairs provided in the call to new_build_id_list();
	modified by	this function and passed to all identifier rendering functions
<access_levels_t> is a table of k/v pairs where k is same as key in cfg.id_handlers and v is the assigned value (if valid)

returns a sequence table of sorted (by hkey - 'handler' key) rendered identifier strings

]]
local function build_id_list(ID_list_coins_t, options_t, access_levels_t)
    local ID_list_t = {}
    local accept
    local func_map = {
        --function map points to functions associated with hkey identifier
        ["ARXIV"] = arxiv,
        ["ASIN"] = asin,
        ["BIBCODE"] = bibcode,
        ["BIORXIV"] = biorxiv,
        ["CITESEERX"] = citeseerx,
        ["DOI"] = doi,
        ["EISSN"] = issn,
        ["HDL"] = hdl,
        ["ISBN"] = isbn,
        ["ISMN"] = ismn,
        ["ISSN"] = issn,
        ["JFM"] = jfm,
        ["JSTOR"] = jstor,
        ["LCCN"] = lccn,
        ["MEDRXIV"] = medrxiv,
        ["MR"] = mr,
        ["OCLC"] = oclc,
        ["OL"] = openlibrary,
        ["OSTI"] = osti,
        ["PMC"] = pmc,
        ["PMID"] = pmid,
        ["RFC"] = rfc,
        ["S2CID"] = s2cid,
        ["SBN"] = sbn,
        ["SSRN"] = ssrn,
        ["USENETID"] = usenet_id,
        ["ZBL"] = zbl
    }

    for hkey, v in pairs(ID_list_coins_t) do
        v, accept = has_accept_as_written(v) -- remove accept-as-written markup if present; accept is boolean true when markup removed; false else
        -- every function gets the options table with value v and accept boolean
        options_t.hkey = hkey -- ~/Configuration handler key
        options_t.id = v -- add that identifier value to the options table
        options_t.accept = accept -- add the accept boolean flag
        options_t.access = access_levels_t[hkey] -- add the access level for those that have an |<identifier-access= parameter
        options_t.handler = cfg.id_handlers[hkey]
        options_t.coins_list_t = ID_list_coins_t -- pointer to ID_list_coins_t; for |asin= and |ol=; also to keep erroneous values out of the citation's metadata
        options_t.coins_list_t[hkey] = v -- id value without accept-as-written markup for metadata

        if options_t.handler.access and not in_array(options_t.handler.access, cfg.keywords_lists["id-access"]) then
            error(cfg.messages["unknown_ID_access"] .. options_t.handler.access) -- here when handler access key set to a value not listed in list of allowed id access keywords
        end

        if func_map[hkey] then
            local id_text = func_map[hkey](options_t) -- call the function to get identifier text and any error message
            table.insert(ID_list_t, {hkey, id_text}) -- add identifier text to the output sequence table
        else
            error(cfg.messages["unknown_ID_key"] .. hkey) -- here when func_map doesn't have a function for hkey
        end
    end

    local function comp(a, b) -- used by following table.sort()
        return a[1]:lower() < b[1]:lower() -- sort by hkey
    end

    table.sort(ID_list_t, comp) -- sequence table of tables sort
    for k, v in ipairs(ID_list_t) do -- convert sequence table of tables to simple sequence table of strings
        ID_list_t[k] = v[2] -- v[2] is the identifier rendering from the call to the various functions in func_map{}
    end

    return ID_list_t
end

--[[--------------------------< O P T I O N S _ C H E C K >----------------------------------------------------

check that certain option parameters have their associated identifier parameters with values

<ID_list_coins_t> is a table of k/v pairs where k is same as key in cfg.id_handlers and v is the assigned value
<ID_support_t> is a sequence table of tables created in citation0() where each subtable has four elements:
	[1] is the support parameter's assigned value; empty string if not set
	[2] is a text string same as key in cfg.id_handlers
	[3] is cfg.error_conditions key used to create error message
	[4] is original ID support parameter name used to create error message
	
returns nothing; on error emits an appropriate error message

]]
local function options_check(ID_list_coins_t, ID_support_t)
    for _, v in ipairs(ID_support_t) do
        if is_set(v[1]) and not ID_list_coins_t[v[2]] then -- when support parameter has a value but matching identifier parameter is missing or empty
            set_message(v[3], (v[4])) -- emit the appropriate error message
        end
    end
end

--[[--------------------------< I D E N T I F I E R _ L I S T S _ G E T >--------------------------------------

Creates two identifier lists: a k/v table of identifiers and their values to be used locally and for use in the
COinS metadata, and a sequence table of the rendered identifier strings that will be included in the rendered
citation.

]]
local function identifier_lists_get(args_t, options_t, ID_support_t)
    local ID_list_coins_t = extract_ids(args_t) -- get a table of identifiers and their values for use locally and for use in COinS
    options_check(ID_list_coins_t, ID_support_t) -- ID support parameters must have matching identifier parameters
    local ID_access_levels_t = extract_id_access_levels(args_t, ID_list_coins_t) -- get a table of identifier access levels
    local ID_list_t = build_id_list(ID_list_coins_t, options_t, ID_access_levels_t) -- get a sequence table of rendered identifier strings

    return ID_list_t, ID_list_coins_t -- return the tables
end

--[[--------------------------< S E T _ S E L E C T E D _ M O D U L E S >--------------------------------------

Sets local cfg table and imported functions table to same (live or sandbox) as that used by the other modules.

]]
local function set_selected_modules(cfg_table_ptr, utilities_page_ptr)
    cfg = cfg_table_ptr

    has_accept_as_written = utilities_page_ptr.has_accept_as_written -- import functions from select Module:Citation/CS1/Utilities module
    is_set = utilities_page_ptr.is_set
    in_array = utilities_page_ptr.in_array
    set_message = utilities_page_ptr.set_message
    select_one = utilities_page_ptr.select_one
    substitute = utilities_page_ptr.substitute
    make_wikilink = utilities_page_ptr.make_wikilink

    z = utilities_page_ptr.z -- table of tables in Module:Citation/CS1/Utilities
end

--[[--------------------------< E X P O R T E D   F U N C T I O N S >------------------------------------------
]]
return {
    auto_link_urls = auto_link_urls, -- table of identifier URLs to be used when auto-linking |title=
    identifier_lists_get = identifier_lists_get, -- experiment to replace individual calls to build_id_list(), extract_ids, extract_id_access_levels
    is_embargoed = is_embargoed,
    set_selected_modules = set_selected_modules
}