Mô đun:Citation/CS1/Identifiers

------------------------------------------------------------------

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

------------------------------------------------------------------

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=

-->

--------------------------------------------------------

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

returns :: when has an for ; nil else

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 ({':', this_wiki_code, ':', wd_article}); -- interwiki-style link without brackets if taken from WD; leading colon required
end

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

----------------------------------------------------------------------------

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

returns the first available of
1. redirect from local wiki's handler table (if enabled)
2. Wikidata (if there is a Wikidata entry for this identifier in the local wiki's language)
3. label specified in the local wiki's handler table


local function link_label_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

--------------------------------------------------------------------------

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 (link_label_make (options), options.label), -- redirect, Wikidata link, or locally specified link (in that order)
options.separator or '&nbsp;',
ext_link
});
end

--------------------------------------------------------------------------

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 (link_label_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

--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

--[=[-------------------------------------------------------------------

for biorxiv, returns true if:
2019-12-11T00:00Z is the date provided in those |biorxiv= parameter values that are dated and in |medrxiv= parameter values at time 00:00:00 UTC
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:
, , – year, month, day parts of the date from the birxiv or medrxiv identifier
'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 must be a number 1–12
return false;
end
if 0 tonumber (d) and 31 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 -----------------------------------------------------

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

---------------------------------------------------------------------------

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

------------------------------------------------------------------------------

LCCN normalization (https://www.loc.gov/marc/lccn-namespace.htmlnormalization)
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

-->

--class= parameter which is not supported in this form
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
is a three-digit number
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:.
where:
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
is a four-digit number
is a 1 or more digit number preceded with a lowercase v; no spaces

the third form, valid from January 2015 is:
arXiv:.
where:
and are as defined for 0704-1412
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 (1 > month or 12 month) or (7 == year and 3 year) or (14 month or 12 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 --------------------------------------------------------------------

Validates (sort of) and formats a bibcode ID.

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

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

---------------------------------------------------------------------------------------------

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

----------------------------------------------------------------------------------------

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_26CiteSeerX_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

----------------------------------------------------------------------------------------------------

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.html2.2.2 -- 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
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 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

----------------------------------------------------------------------------------------------------

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

--------------------------------------------------------------------------------------------------

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 1965 > tonumber(year) then
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 ('^%dX?$') nil then -- fail if isbn_str has 'X' anywhere but last position
return return_result (false, cfg.err_msg_supl.form);
end
if not is_valid_isxn (id, 10) then -- test isbn-10 for numerical validity
return return_result (false, cfg.err_msg_supl.check); -- fail if isbn-10 is not numerically valid
end
if id:find ('^63[01]') then -- 630xxxxxxx and 631xxxxxxx are (apparently) not valid isbn group ids but are used by amazon as numeric identifiers (asin)
return return_result (false, cfg.err_msg_supl.group); -- fail if isbn-10 begins with 630/1
end
return return_result (true, cfg.err_msg_supl.check); -- pass if isbn-10 is numerically valid
else
if id:match ('^%d+$') 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

--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

--------------------------------------------------------------------------------------------------

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 (link_label_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

--issn=0819 4327 gives: 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 ("^%dX?$" ) 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

---------------------------------------------------------------------------------------------------

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

------------------------------------------------------------------------------------------------

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

--[[------------------------------------------------------------------------------------------------

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

---------------------------------------------------------------------------------------------

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 -- 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

------------------------------------------------------------------------------------------------------

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

--------------------------------------------------------------------------------------------------

Validate and format an OCLC ID. https://www.oclc.org/batchload/controlnumber.en.html
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 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

------------------------------------------------------------------------------------

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

--------------------------------------------------------------------------------------------------

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 ------------------------------------------------------------------------

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= 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 ----------------------------------------------------------------------

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 ------------------------------------------------------------------------

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 --------------------------------------------------------------------

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 ------------------------------------------------------------------------

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 ('^%dX?$') == 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

--------------------------------------------------------------------------------------------------

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 ------------------------------------------------------------

Validate and format a usenet message id. Simple error checking, looks for 'id-left@id-right' not enclosed in
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
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

---------------------------------------------------------------------------------------------------

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

-->

--[[--------------------------------------------------------------------------------------

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

--[[----------------------------------------------------------------

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

--------------------------------------------------------------------------------

render the identifiers into a sorted sequence table

is a table of k/v pairs where k is same as key in cfg.id_handlers and v is the assigned value
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
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 |----------------------------------------------------

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

is a table of k/v pairs where k is same as key in cfg.id_handlers and v is the assigned value
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

------------------------------------------------------------------

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

------------------------------------------------------------------

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

----------------------------------------------------------------------

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;
}