validation.year_date_check (Year, A:ORIGIN ('Year'), Date, A:ORIGIN ('Date'), error_list);
end  
if 0 == #error_list then -- error free dates only; 0 when error_list is empty
local modified = false; -- flag  
if utilities.is_set (DF) then -- if we need to reformat dates
modified = validation.reformat_dates (date_parameters_list, DF); -- reformat to DF format, use long month names if appropriate
end  
if true == validation.date_hyphen_to_dash (date_parameters_list) then -- convert hyphens to dashes where appropriate
modified = true;
utilities.set_message ('maint_date_format'); -- hyphens were converted so add maint category
end  
-- for those wikis that can and want to have English date names translated to the local language; not supported at en.wiki
if cfg.date_name_auto_xlate_enable and validation.date_name_xlate (date_parameters_list, cfg.date_digit_auto_xlate_enable ) then
utilities.set_message ('maint_date_auto_xlated'); -- add maint cat
modified = true;
end  
if modified then -- if the date_parameters_list values were modified
AccessDate = date_parameters_list['access-date'].val; -- overwrite date holding parameters with modified values
ArchiveDate = date_parameters_list['archive-date'].val;
Date = date_parameters_list['date'].val;
DoiBroken = date_parameters_list['doi-broken-date'].val;
PublicationDate = date_parameters_list['publication-date'].val;
end  
if archive_url_timestamp and utilities.is_set (ArchiveDate) then
validation.archive_date_check (ArchiveDate, archive_url_timestamp, DF); -- does YYYYMMDD in archive_url_timestamp match date in ArchiveDate
end
else
utilities.set_message ('err_bad_date', {utilities.make_sep_list (#error_list, error_list)}); -- add this error message
end
end -- end of do  
if utilities.in_array (config.CitationClass, {'book', 'encyclopaedia'}) or -- , ; TODO: and others?
('citation' == config.CitationClass and utilities.is_set (Encyclopedia)) or -- as an encylopedia citation
('citation' == config.CitationClass and not utilities.is_set (Periodical)) then -- as a book citation
if utilities.is_set (PublicationPlace) then
if not utilities.is_set (PublisherName) then
local date = COinS_date.rftdate and tonumber (COinS_date.rftdate:match ('%d%d%d%d')); -- get year portion of COinS date (because in Arabic numerals); convert string to number
if date and (1850 <= date) then -- location has no publisher; if date is 1850 or later
utilities.set_message ('maint_location_no_publisher'); -- add maint cat
end
else -- PublisherName has a value
if cfg.keywords_xlate[*] == PublisherName then -- if that value is * (only for book and encyclopedia citations)
PublisherName = ''; -- unset
end
end
end
end  
local ID_list = {}; -- sequence table of rendered identifiers
local ID_list_coins = {}; -- table of identifiers and their values from args; key is same as cfg.id_handlers's key
local Class = A['Class']; -- arxiv class identifier  
local ID_support = {
{A['ASINTLD'], 'ASIN', 'err_asintld_missing_asin', A:ORIGIN ('ASINTLD')},
{DoiBroken, 'DOI', 'err_doibroken_missing_doi', A:ORIGIN ('DoiBroken')},
{Embargo, 'PMC', 'err_embargo_missing_pmc', A:ORIGIN ('Embargo')},
}  
ID_list, ID_list_coins = identifiers.identifier_lists_get (args, {DoiBroken = DoiBroken, ASINTLD = A['ASINTLD'], Embargo = Embargo, Class = Class}, ID_support);  
-- Account for the oddities that are , , , , , before generation of COinS data.
if utilities.in_array (config.CitationClass, whitelist.preprint_template_list_t) then -- |arxiv= or |eprint= required for cite arxiv; |biorxiv=, |citeseerx=, |medrxiv=, |ssrn= required for their templates
if not (args[cfg.id_handlers[config.CitationClass:upper].parameters[1]] or -- can't use ID_list_coins k/v table here because invalid parameters omitted
args[cfg.id_handlers[config.CitationClass:upper].parameters[2]]) then -- which causes unexpected parameter missing error message
utilities.set_message ('err_' .. config.CitationClass .. '_missing'); -- add error message
end  
Periodical = ({['arxiv'] = 'arXiv', ['biorxiv'] = 'bioRxiv', ['citeseerx'] = 'CiteSeerX', ['medrxiv'] = 'medRxiv', ['ssrn'] = 'Social Science Research Network'})[config.CitationClass];
end  
-- Link the title of the work if no |url= was provided, but we have a |pmc= or a |doi= with |doi-access=free  
if config.CitationClass == "journal" and not utilities.is_set (URL) and not utilities.is_set (TitleLink) and not utilities.in_array (cfg.keywords_xlate[Title], {'off', *}) then -- TODO: remove * once existing citations have been switched to 'off', so '' can be used as token for "no title" instead
if '' ~= cfg.keywords_xlate[auto_select] then -- if auto-linking not disabled
if identifiers.auto_link_urls[auto_select] then -- manual selection
URL = identifiers.auto_link_urls[auto_select]; -- set URL to be the same as identifier's external link
URL_origin = cfg.id_handlers[auto_select:upper].parameters[1]; -- set URL_origin to parameter name for use in error message if citation is missing a |title=
elseif identifiers.auto_link_urls['pmc'] then -- auto-select PMC
URL = identifiers.auto_link_urls['pmc']; -- set URL to be the same as the PMC external link if not embargoed
URL_origin = cfg.id_handlers['PMC'].parameters[1]; -- set URL_origin to parameter name for use in error message if citation is missing a |title=
elseif identifiers.auto_link_urls['doi'] then -- auto-select DOI
URL = identifiers.auto_link_urls['doi'];
URL_origin = cfg.id_handlers['DOI'].parameters[1];
end
end  
if utilities.is_set (URL) then -- set when using an identifier-created URL
if utilities.is_set (AccessDate) then -- |access-date= requires |url=; identifier-created URL is not |url=
utilities.set_message ('err_accessdate_missing_url'); -- add an error message
AccessDate = ''; -- unset
end  
if utilities.is_set (ArchiveURL) then -- |archive-url= requires |url=; identifier-created URL is not |url=
utilities.set_message ('err_archive_missing_url'); -- add an error message
ArchiveURL = ''; -- unset
end
end
end  
-- At this point fields may be nil if they weren't specified in the template use. We can use that fact.
-- Test if citation has no title
if not utilities.is_set (Title) and not utilities.is_set (TransTitle) and not utilities.is_set (ScriptTitle) then -- has special case for cite episode
utilities.set_message ('err_citation_missing_title', {'episode' == config.CitationClass and 'series' or 'title'});
end  
if utilities.in_array (cfg.keywords_xlate[Title], {'off', ''}) and
utilities.in_array (config.CitationClass, {'journal', 'citation'}) and
(utilities.is_set (Periodical) or utilities.is_set (ScriptPeriodical)) and
('journal' == Periodical_origin or 'script-journal' == ScriptPeriodical_origin) then -- special case for journal cites
Title = ''; -- set title to empty string
utilities.set_message ('maint_untitled'); -- add maint cat
end  
-- COinS metadata (see <http://ocoins.info/>) for automated parsing of citation information.
-- handle the oddity that is cite encyclopedia and . Here we presume that
-- when Periodical, Title, and Chapter are all set, then Periodical is the book (encyclopedia) title, Title
-- is the article title, and Chapter is a section within the article. So, we remap  
local coins_chapter = Chapter; -- default assuming that remapping not required
local coins_title = Title; -- et tu
if 'encyclopaedia' == config.CitationClass or ('citation' == config.CitationClass and utilities.is_set (Encyclopedia)) then
if utilities.is_set (Chapter) and utilities.is_set (Title) and utilities.is_set (Periodical) then -- if all are used then
coins_chapter = Title; -- remap
coins_title = Periodical;
end
end
local coins_author = a; -- default for coins rft.au
if 0 < #c then -- but if contributor list
coins_author = c; -- use that instead
end  
-- this is the function call to COinS
local OCinSoutput = metadata.COinS({
['Periodical'] = utilities.strip_apostrophe_markup (Periodical), -- no markup in the metadata
['Encyclopedia'] = Encyclopedia, -- just a flag; content ignored by ~/COinS