Difference between revisions of "Module:Citation/CS1/Utilities"

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Mediawiki>Trappist the monk
(update per RfC;)
Line 1: Line 1:
 
 
local z = {
 
local z = {
error_categories = {}; -- for categorizing citations that contain errors
+
error_cats_t = {}; -- for categorizing citations that contain errors
error_ids = {};
+
error_ids_t = {}; -- list of error identifiers; used to prevent duplication of certain errors; local to this module
message_tail = {};
+
error_msgs_t = {}; -- sequence table of error messages
maintenance_cats = {}; -- for categorizing citations that aren't erroneous per se, but could use a little work
+
maint_cats_t = {}; -- for categorizing citations that aren't erroneous per se, but could use a little work
properties_cats = {}; -- for categorizing citations based on certain properties, language of source for instance
+
prop_cats_t = {}; -- for categorizing citations based on certain properties, language of source for instance
 +
prop_keys_t = {}; -- for adding classes to the citation's <cite> tag
 
};
 
};
  
Line 13: Line 13:
  
 
local cfg; -- table of tables imported from selected Module:Citation/CS1/Configuration
 
local cfg; -- table of tables imported from selected Module:Citation/CS1/Configuration
 
 
--[[--------------------------< H A S _ A C C E P T _ A S _ W R I T T E N >------------------------------------
 
 
When <str> is wholly wrapped in accept-as-written markup, return <str> without markup and true; return <str> and false else
 
 
with allow_empty = false, <str> must have at least one character inside the markup
 
with allow_empty = true, <str> the markup frame can be empty like (()) to distinguish an empty template parameter from the specific condition "has no applicable value" in citation-context.
 
 
After further evaluation the two cases might be merged at a later stage, but should be kept separated for now.
 
 
]]
 
 
local function has_accept_as_written (str, allow_empty)
 
local count;
 
if true == allow_empty then
 
str, count = str:gsub ('^%(%((.*)%)%)$', '%1'); -- allows (()) to be an empty set
 
else
 
str, count = str:gsub ('^%(%((.+)%)%)$', '%1');
 
end
 
return str, 0 ~= count;
 
end
 
  
  
Line 64: Line 42:
 
end
 
end
 
return false;
 
return false;
 +
end
 +
 +
 +
--[[--------------------------< H A S _ A C C E P T _ A S _ W R I T T E N >------------------------------------
 +
 +
When <str> is wholly wrapped in accept-as-written markup, return <str> without markup and true; return <str> and false else
 +
 +
with allow_empty = false, <str> must have at least one character inside the markup
 +
with allow_empty = true, <str> the markup frame can be empty like (()) to distinguish an empty template parameter from the specific condition "has no applicable value" in citation-context.
 +
 +
After further evaluation the two cases might be merged at a later stage, but should be kept separated for now.
 +
 +
]]
 +
 +
local function has_accept_as_written (str, allow_empty)
 +
if not is_set (str) then
 +
return str, false;
 +
end
 +
 +
local count;
 +
 +
if true == allow_empty then
 +
str, count = str:gsub ('^%(%((.*)%)%)$', '%1'); -- allows (()) to be an empty set
 +
else
 +
str, count = str:gsub ('^%(%((.+)%)%)$', '%1');
 +
end
 +
return str, 0 ~= count;
 
end
 
end
  
Line 69: Line 74:
 
--[[--------------------------< S U B S T I T U T E >----------------------------------------------------------
 
--[[--------------------------< S U B S T I T U T E >----------------------------------------------------------
  
Populates numbered arguments in a message string using an argument table.
+
Populates numbered arguments in a message string using an argument table. <args> may be a single string or a
 +
sequence table of multiple strings.
  
 
]]
 
]]
Line 80: Line 86:
 
--[[--------------------------< E R R O R _ C O M M E N T >----------------------------------------------------
 
--[[--------------------------< E R R O R _ C O M M E N T >----------------------------------------------------
  
Wraps error messages with CSS markup according to the state of hidden.
+
Wraps error messages with CSS markup according to the state of hidden. <content> may be a single string or a
 +
sequence table of multiple strings.
  
 
]]
 
]]
Line 86: Line 93:
 
local function error_comment (content, hidden)
 
local function error_comment (content, hidden)
 
return substitute (hidden and cfg.presentation['hidden-error'] or cfg.presentation['visible-error'], content);
 
return substitute (hidden and cfg.presentation['hidden-error'] or cfg.presentation['visible-error'], content);
 +
end
 +
 +
 +
--[[--------------------------< H Y P H E N _ T O _ D A S H >--------------------------------------------------
 +
 +
Converts a hyphen to a dash under certain conditions.  The hyphen must separate
 +
like items; unlike items are returned unmodified.  These forms are modified:
 +
letter - letter (A - B)
 +
digit - digit (4-5)
 +
digit separator digit - digit separator digit (4.1-4.5 or 4-1-4-5)
 +
letterdigit - letterdigit (A1-A5) (an optional separator between letter and
 +
digit is supported – a.1-a.5 or a-1-a-5)
 +
digitletter - digitletter (5a - 5d) (an optional separator between letter and
 +
digit is supported – 5.a-5.d or 5-a-5-d)
 +
 +
any other forms are returned unmodified.
 +
 +
str may be a comma- or semicolon-separated list
 +
 +
]]
 +
 +
local function hyphen_to_dash (str)
 +
if not is_set (str) then
 +
return str;
 +
end
 +
 +
local accept; -- boolean
 +
 +
str = str:gsub ("(%(%(.-%)%))", function(m) return m:gsub(",", ","):gsub(";", ";") end) -- replace commas and semicolons in accept-as-written markup with similar unicode characters so they'll be ignored during the split
 +
str = str:gsub ('&[nm]dash;', {['&ndash;'] = '–', ['&mdash;'] = '—'}); -- replace &mdash; and &ndash; entities with their characters; semicolon mucks up the text.split
 +
str = str:gsub ('&#45;', '-'); -- replace HTML numeric entity with hyphen character
 +
str = str:gsub ('&nbsp;', ' '); -- replace &nbsp; entity with generic keyboard space character
 +
 +
local out = {};
 +
local list = mw.text.split (str, '%s*[,;]%s*'); -- split str at comma or semicolon separators if there are any
 +
 +
for _, item in ipairs (list) do -- for each item in the list
 +
item, accept = has_accept_as_written (item); -- remove accept-this-as-written markup when it wraps all of item
 +
if not accept and mw.ustring.match (item, '^%w*[%.%-]?%w+%s*[%-–—]%s*%w*[%.%-]?%w+$') then -- if a hyphenated range or has endash or emdash separators
 +
if item:match ('^%a+[%.%-]?%d+%s*%-%s*%a+[%.%-]?%d+$') or -- letterdigit hyphen letterdigit (optional separator between letter and digit)
 +
item:match ('^%d+[%.%-]?%a+%s*%-%s*%d+[%.%-]?%a+$') or -- digitletter hyphen digitletter (optional separator between digit and letter)
 +
item:match ('^%d+[%.%-]%d+%s*%-%s*%d+[%.%-]%d+$') or -- digit separator digit hyphen digit separator digit
 +
item:match ('^%d+%s*%-%s*%d+$') or -- digit hyphen digit
 +
item:match ('^%a+%s*%-%s*%a+$') then -- letter hyphen letter
 +
item = item:gsub ('(%w*[%.%-]?%w+)%s*%-%s*(%w*[%.%-]?%w+)', '%1–%2'); -- replace hyphen, remove extraneous space characters
 +
else
 +
item = mw.ustring.gsub (item, '%s*[–—]%s*', '–'); -- for endash or emdash separated ranges, replace em with en, remove extraneous whitespace
 +
end
 +
end
 +
table.insert (out, item); -- add the (possibly modified) item to the output table
 +
end
 +
 +
local temp_str = ''; -- concatenate the output table into a comma separated string
 +
temp_str, accept = has_accept_as_written (table.concat (out, ', ')); -- remove accept-this-as-written markup when it wraps all of concatenated out
 +
if accept then
 +
temp_str = has_accept_as_written (str); -- when global markup removed, return original str; do it this way to suppress boolean second return value
 +
return temp_str:gsub(",", ","):gsub(";", ";");
 +
else
 +
return temp_str:gsub(",", ","):gsub(";", ";"); -- else, return assembled temp_str
 +
end
 
end
 
end
  
Line 110: Line 177:
 
--[[--------------------------< S E T _ M E S S A G E >----------------------------------------------------------
 
--[[--------------------------< S E T _ M E S S A G E >----------------------------------------------------------
  
Sets an error condition and returns the appropriate error message.  The actual placement of the error message in the output is
+
Sets an error message using the ~/Configuration error_conditions{} table along with arguments supplied in the function
the responsibility of the calling function.
+
call, inserts the resulting message in z.error_msgs_t{} sequence table, and returns the error message.
  
TODO: change z.error_categories and z.maintenance_cats to have the form cat_name = true; to avoid dups without having to have an extra cat
+
<error_id> – key value for appropriate error handler in ~/Configuration error_conditions{} table
 +
<arguments> – may be a single string or a sequence table of multiple strings to be subsititued into error_conditions[error_id].message
 +
<raw> – boolean
 +
true – causes this function to return the error message not wrapped in visible-error, hidden-error span tag;
 +
returns error_conditions[error_id].hidden as a second return value
 +
does not add message to z.error_msgs_t sequence table
 +
false, nil – adds message wrapped in visible-error, hidden-error span tag to z.error_msgs_t
 +
returns the error message wrapped in visible-error, hidden-error span tag; there is no second return value
 +
<prefix> – string to be prepended to <message> -- TODO: remove support for these unused(?) arguments?
 +
<suffix> – string to be appended to <message>
 +
 
 +
TODO: change z.error_cats_t and z.maint_cats_t to have the form cat_name = true?  this to avoid dups without having to have an extra table
  
 
]]
 
]]
local added_maint_cats = {} -- list of maintenance categories that have been added to z.maintenance_cats; TODO: figure out how to delete this table
+
 
 +
local added_maint_cats = {} -- list of maintenance categories that have been added to z.maint_cats_t; TODO: figure out how to delete this table
  
 
local function set_message (error_id, arguments, raw, prefix, suffix)
 
local function set_message (error_id, arguments, raw, prefix, suffix)
Line 129: Line 208:
 
elseif is_set (error_state.category) then
 
elseif is_set (error_state.category) then
 
if error_state.message then -- when error_state.message defined, this is an error message
 
if error_state.message then -- when error_state.message defined, this is an error message
table.insert (z.error_categories, error_state.category);
+
table.insert (z.error_cats_t, error_state.category);
 
else
 
else
 
if not added_maint_cats[error_id] then
 
if not added_maint_cats[error_id] then
 
added_maint_cats[error_id] = true; -- note that we've added this category
 
added_maint_cats[error_id] = true; -- note that we've added this category
table.insert (z.maintenance_cats, substitute (error_state.category, arguments)); -- make cat name then add to table
+
table.insert (z.maint_cats_t, substitute (error_state.category, arguments)); -- make cat name then add to table
 
end
 
end
 
return; -- because no message, nothing more to do
 
return; -- because no message, nothing more to do
Line 156: Line 235:
 
});
 
});
  
z.error_ids[error_id] = true;
+
z.error_ids_t[error_id] = true;
if z.error_ids['err_citation_missing_title'] and -- if missing-title error already noted
+
if z.error_ids_t['err_citation_missing_title'] and -- if missing-title error already noted
 
in_array (error_id, {'err_bare_url_missing_title', 'err_trans_missing_title'}) then -- and this error is one of these
 
in_array (error_id, {'err_bare_url_missing_title', 'err_trans_missing_title'}) then -- and this error is one of these
 
return '', false; -- don't bother because one flavor of missing title is sufficient
 
return '', false; -- don't bother because one flavor of missing title is sufficient
Line 164: Line 243:
 
message = table.concat ({prefix, message, suffix});
 
message = table.concat ({prefix, message, suffix});
  
if raw == true then
+
if true == raw then
return message, error_state.hidden;
+
return message, error_state.hidden; -- return message not wrapped in visible-error, hidden-error span tag
 
end
 
end
  
return error_comment (message, error_state.hidden);
+
message = error_comment (message, error_state.hidden); -- wrap message in visible-error, hidden-error span tag
 +
table.insert (z.error_msgs_t, message); -- add it to the messages sequence table
 +
return message; -- and done; return value generally not used but is used as a flag in various functions of ~/Identifiers
 
end
 
end
  
Line 199: Line 280:
 
end
 
end
  
if is_set (args[alias]) then -- alias is in the template's argument list
+
if is_set (args[alias]) then -- alias is in the template's argument list
 
if value ~= nil and selected ~= alias then -- if we have already selected one of the aliases
 
if value ~= nil and selected ~= alias then -- if we have already selected one of the aliases
 
local skip;
 
local skip;
Line 222: Line 303:
 
--[[--------------------------< A D D _ M A I N T _ C A T >------------------------------------------------------
 
--[[--------------------------< A D D _ M A I N T _ C A T >------------------------------------------------------
  
Adds a category to z.maintenance_cats using names from the configuration file with additional text if any.
+
Adds a category to z.maint_cats_t using names from the configuration file with additional text if any.
To prevent duplication, the added_maint_cats table lists the categories by key that have been added to z.maintenance_cats.
+
To prevent duplication, the added_maint_cats table lists the categories by key that have been added to z.maint_cats_t.
  
 
]]
 
]]
Line 230: Line 311:
 
if not added_maint_cats [key] then
 
if not added_maint_cats [key] then
 
added_maint_cats [key] = true; -- note that we've added this category
 
added_maint_cats [key] = true; -- note that we've added this category
table.insert (z.maintenance_cats, substitute (cfg.maint_cats [key], arguments)); -- make name then add to table
+
table.insert (z.maint_cats_t, substitute (cfg.maint_cats [key], arguments)); -- make name then add to table
 
end
 
end
 
end
 
end
Line 237: Line 318:
 
--[[--------------------------< A D D _ P R O P _ C A T >--------------------------------------------------------
 
--[[--------------------------< A D D _ P R O P _ C A T >--------------------------------------------------------
  
Adds a category to z.properties_cats using names from the configuration file with additional text if any.
+
Adds a category to z.prop_cats_t using names from the configuration file with additional text if any.
  
 
foreign_lang_source and foreign_lang_source_2 keys have a language code appended to them so that multiple languages
 
foreign_lang_source and foreign_lang_source_2 keys have a language code appended to them so that multiple languages
Line 246: Line 327:
 
]]
 
]]
  
local added_prop_cats = {}; -- list of property categories that have been added to z.properties_cats
+
local added_prop_cats = {}; -- list of property categories that have been added to z.prop_cats_t
  
local function add_prop_cat (key, arguments)
+
local function add_prop_cat (key, arguments, key_modifier)
if not added_prop_cats [key] then
+
local key_modified = key .. ((key_modifier and key_modifier) or ''); -- modify <key> with <key_modifier> if present and not nil
added_prop_cats [key] = true; -- note that we've added this category
+
key = key:gsub ('(foreign_lang_source_?2?)%a%a%a?[%a%-]*', '%1'); -- strip lang code from keyname
+
if not added_prop_cats [key_modified] then
table.insert (z.properties_cats, substitute (cfg.prop_cats [key], arguments)); -- make name then add to table
+
added_prop_cats [key_modified] = true; -- note that we've added this category
 +
table.insert (z.prop_cats_t, substitute (cfg.prop_cats [key], arguments)); -- make name then add to table
 +
table.insert (z.prop_keys_t, 'cs1-prop-' .. key); -- convert key to class for use in the citation's <cite> tag
 
end
 
end
 
end
 
end
Line 273: Line 356:
 
if str:sub (-1, -1) == "'" then str = str .. "<span></span>"; end
 
if str:sub (-1, -1) == "'" then str = str .. "<span></span>"; end
 
 
-- Remove newlines as they break italics.
+
return str:gsub ('\n', ' '); -- Remove newlines as they break italics.
return str:gsub ('\n', ' ');
 
 
 
 
end
 
end
  
Line 366: Line 447:
 
end
 
end
 
table.insert (error_list, wrap_style ('parameter', selected));
 
table.insert (error_list, wrap_style ('parameter', selected));
table.insert (z.message_tail, {set_message (error_condition, {make_sep_list (#error_list, error_list)}, true)});
+
set_message (error_condition, {make_sep_list (#error_list, error_list)});
 
end
 
end
 
 
Line 451: Line 532:
 
while true do
 
while true do
 
if argument:find ("'''''", 1, true) then -- bold italic (5)
 
if argument:find ("'''''", 1, true) then -- bold italic (5)
argument, flag = argument:gsub ("%'%'%'%'%'", ""); -- remove all instances of it
+
argument, flag = argument:gsub ("%'%'%'%'%'", ""); -- remove all instances of it
elseif argument:find ("''''", 1, true) then -- italic start and end without content (4)
+
elseif argument:find ("''''", 1, true) then -- italic start and end without content (4)
 
argument, flag=argument:gsub ("%'%'%'%'", "");
 
argument, flag=argument:gsub ("%'%'%'%'", "");
elseif argument:find ("'''", 1, true) then -- bold (3)
+
elseif argument:find ("'''", 1, true) then -- bold (3)
 
argument, flag=argument:gsub ("%'%'%'", "");
 
argument, flag=argument:gsub ("%'%'%'", "");
 
elseif argument:find ("''", 1, true) then -- italic (2)
 
elseif argument:find ("''", 1, true) then -- italic (2)
Line 487: Line 568:
 
error_comment = error_comment,
 
error_comment = error_comment,
 
has_accept_as_written = has_accept_as_written,
 
has_accept_as_written = has_accept_as_written,
 +
hyphen_to_dash = hyphen_to_dash,
 
in_array = in_array,
 
in_array = in_array,
 
is_set = is_set,
 
is_set = is_set,

Revision as of 14:11, 22 January 2022

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

local z = {
	error_cats_t = {};															-- for categorizing citations that contain errors
	error_ids_t = {};															-- list of error identifiers; used to prevent duplication of certain errors; local to this module
	error_msgs_t = {};															-- sequence table of error messages
	maint_cats_t = {};															-- for categorizing citations that aren't erroneous per se, but could use a little work
	prop_cats_t = {};															-- for categorizing citations based on certain properties, language of source for instance
	prop_keys_t = {};															-- for adding classes to the citation's <cite> tag
};


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

local cfg;																		-- table of tables imported from selected Module:Citation/CS1/Configuration


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

Returns true if argument is set; false otherwise. Argument is 'set' when it exists (not nil) or when it is not an empty string.

]]

local function is_set (var)
	return not (var == nil or var == '');
end


--[[--------------------------< I N _ A R R A Y >--------------------------------------------------------------

Whether needle is in haystack

]]

local function in_array (needle, haystack)
	if needle == nil then
		return false;
	end
	for n, v in ipairs (haystack) do
		if v == needle then
			return n;
		end
	end
	return false;
end


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

When <str> is wholly wrapped in accept-as-written markup, return <str> without markup and true; return <str> and false else

with allow_empty = false, <str> must have at least one character inside the markup
with allow_empty = true, <str> the markup frame can be empty like (()) to distinguish an empty template parameter from the specific condition "has no applicable value" in citation-context.

After further evaluation the two cases might be merged at a later stage, but should be kept separated for now.

]]

local function has_accept_as_written (str, allow_empty)
	if not is_set (str) then
		return str, false;
	end

	local count;

	if true == allow_empty then
		str, count = str:gsub ('^%(%((.*)%)%)$', '%1'); 						-- allows (()) to be an empty set
	else
		str, count = str:gsub ('^%(%((.+)%)%)$', '%1');
	end
	return str, 0 ~= count;
end


--[[--------------------------< S U B S T I T U T E >----------------------------------------------------------

Populates numbered arguments in a message string using an argument table. <args> may be a single string or a
sequence table of multiple strings.

]]

local function substitute (msg, args)
	return args and mw.message.newRawMessage (msg, args):plain() or msg;
end


--[[--------------------------< E R R O R _ C O M M E N T >----------------------------------------------------

Wraps error messages with CSS markup according to the state of hidden. <content> may be a single string or a
sequence table of multiple strings.

]]

local function error_comment (content, hidden)
	return substitute (hidden and cfg.presentation['hidden-error'] or cfg.presentation['visible-error'], content);
end


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

Converts a hyphen to a dash under certain conditions.  The hyphen must separate
like items; unlike items are returned unmodified.  These forms are modified:
	letter - letter (A - B)
	digit - digit (4-5)
	digit separator digit - digit separator digit (4.1-4.5 or 4-1-4-5)
	letterdigit - letterdigit (A1-A5) (an optional separator between letter and
		digit is supported – a.1-a.5 or a-1-a-5)
	digitletter - digitletter (5a - 5d) (an optional separator between letter and
		digit is supported – 5.a-5.d or 5-a-5-d)

any other forms are returned unmodified.

str may be a comma- or semicolon-separated list

]]

local function hyphen_to_dash (str)
	if not is_set (str) then
		return str;
	end

	local accept;																-- boolean

	str = str:gsub ("(%(%(.-%)%))", function(m) return m:gsub(",", ","):gsub(";", ";") end) -- replace commas and semicolons in accept-as-written markup with similar unicode characters so they'll be ignored during the split	
	str = str:gsub ('&[nm]dash;', {['&ndash;'] = '–', ['&mdash;'] = '—'});		-- replace &mdash; and &ndash; entities with their characters; semicolon mucks up the text.split
	str = str:gsub ('&#45;', '-'); -- replace HTML numeric entity with hyphen character
	str = str:gsub ('&nbsp;', ' '); -- replace &nbsp; entity with generic keyboard space character
	
	local out = {};
	local list = mw.text.split (str, '%s*[,;]%s*');								-- split str at comma or semicolon separators if there are any

	for _, item in ipairs (list) do												-- for each item in the list
		item, accept = has_accept_as_written (item);							-- remove accept-this-as-written markup when it wraps all of item
		if not accept and mw.ustring.match (item, '^%w*[%.%-]?%w+%s*[%-–—]%s*%w*[%.%-]?%w+$') then	-- if a hyphenated range or has endash or emdash separators
			if item:match ('^%a+[%.%-]?%d+%s*%-%s*%a+[%.%-]?%d+$') or			-- letterdigit hyphen letterdigit (optional separator between letter and digit)
				item:match ('^%d+[%.%-]?%a+%s*%-%s*%d+[%.%-]?%a+$') or			-- digitletter hyphen digitletter (optional separator between digit and letter)
				item:match ('^%d+[%.%-]%d+%s*%-%s*%d+[%.%-]%d+$') or			-- digit separator digit hyphen digit separator digit
				item:match ('^%d+%s*%-%s*%d+$') or								-- digit hyphen digit
				item:match ('^%a+%s*%-%s*%a+$') then							-- letter hyphen letter
					item = item:gsub ('(%w*[%.%-]?%w+)%s*%-%s*(%w*[%.%-]?%w+)', '%1–%2');	-- replace hyphen, remove extraneous space characters
			else
				item = mw.ustring.gsub (item, '%s*[–—]%s*', '–');				-- for endash or emdash separated ranges, replace em with en, remove extraneous whitespace
			end
		end
		table.insert (out, item);												-- add the (possibly modified) item to the output table
	end

	local temp_str = '';														-- concatenate the output table into a comma separated string
	temp_str, accept = has_accept_as_written (table.concat (out, ', '));		-- remove accept-this-as-written markup when it wraps all of concatenated out
	if accept then
		temp_str = has_accept_as_written (str);									-- when global markup removed, return original str; do it this way to suppress boolean second return value
		return temp_str:gsub(",", ","):gsub(";", ";");
	else
		return temp_str:gsub(",", ","):gsub(";", ";");						-- else, return assembled temp_str
	end
end


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

Makes a wikilink; when both link and display text is provided, returns a wikilink in the form [[L|D]]; if only
link is provided (or link and display are the same), returns a wikilink in the form [[L]]; if neither are
provided or link is omitted, returns an empty string.

]=]

local function make_wikilink (link, display)
	if not is_set (link) then return '' end

	if is_set (display) and link ~= display then			
		return table.concat ({'[[', link, '|', display, ']]'});			
	else
		return table.concat ({'[[', link, ']]'});
	end
end


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

Sets an error message using the ~/Configuration error_conditions{} table along with arguments supplied in the function
call, inserts the resulting message in z.error_msgs_t{} sequence table, and returns the error message.

<error_id> – key value for appropriate error handler in ~/Configuration error_conditions{} table 
<arguments> – may be a single string or a sequence table of multiple strings to be subsititued into error_conditions[error_id].message
<raw> – boolean
	true –	causes this function to return the error message not wrapped in visible-error, hidden-error span tag;
			returns error_conditions[error_id].hidden as a second return value
			does not add message to z.error_msgs_t sequence table
	false, nil – adds message wrapped in visible-error, hidden-error span tag to z.error_msgs_t
			returns the error message wrapped in visible-error, hidden-error span tag; there is no second return value
<prefix> – string to be prepended to <message>									-- TODO: remove support for these unused(?) arguments?
<suffix> – string to be appended to <message>

TODO: change z.error_cats_t and z.maint_cats_t to have the form cat_name = true?  this to avoid dups without having to have an extra table

]]

local added_maint_cats = {}														-- list of maintenance categories that have been added to z.maint_cats_t; TODO: figure out how to delete this table

local function set_message (error_id, arguments, raw, prefix, suffix)
	local error_state = cfg.error_conditions[error_id];
	
	prefix = prefix or '';
	suffix = suffix or '';
	
	if error_state == nil then
		error (cfg.messages['undefined_error'] .. ': ' .. error_id);			-- because missing error handler in Module:Citation/CS1/Configuration

	elseif is_set (error_state.category) then
		if error_state.message then												-- when error_state.message defined, this is an error message
			table.insert (z.error_cats_t, error_state.category);
		else
			if not added_maint_cats[error_id] then
				added_maint_cats[error_id] = true;								-- note that we've added this category
				table.insert (z.maint_cats_t, substitute (error_state.category, arguments));	-- make cat name then add to table
			end
			return;																-- because no message, nothing more to do
		end
	end

	local message = substitute (error_state.message, arguments);

	message = table.concat (
		{
		message,
		' (',
		make_wikilink (
			table.concat (
				{
				cfg.messages['help page link'],
				'#',
				error_state.anchor
				}),
			cfg.messages['help page label']),
		')'
		});

	z.error_ids_t[error_id] = true;
	if z.error_ids_t['err_citation_missing_title'] and							-- if missing-title error already noted
		in_array (error_id, {'err_bare_url_missing_title', 'err_trans_missing_title'}) then		-- and this error is one of these
			return '', false;													-- don't bother because one flavor of missing title is sufficient
	end
	
	message = table.concat ({prefix, message, suffix});

	if true == raw then
		return message, error_state.hidden;										-- return message not wrapped in visible-error, hidden-error span tag
	end		

	message = error_comment (message, error_state.hidden);						-- wrap message in visible-error, hidden-error span tag
	table.insert (z.error_msgs_t, message);										-- add it to the messages sequence table
	return message;																-- and done; return value generally not used but is used as a flag in various functions of ~/Identifiers
end


--[[-------------------------< I S _ A L I A S _ U S E D >-----------------------------------------------------

This function is used by select_one() to determine if one of a list of alias parameters is in the argument list
provided by the template.

Input:
	args – pointer to the arguments table from calling template
	alias – one of the list of possible aliases in the aliases lists from Module:Citation/CS1/Configuration
	index – for enumerated parameters, identifies which one
	enumerated – true/false flag used to choose how enumerated aliases are examined
	value – value associated with an alias that has previously been selected; nil if not yet selected
	selected – the alias that has previously been selected; nil if not yet selected
	error_list – list of aliases that are duplicates of the alias already selected

Returns:
	value – value associated with alias we selected or that was previously selected or nil if an alias not yet selected
	selected – the alias we selected or the alias that was previously selected or nil if an alias not yet selected

]]

local function is_alias_used (args, alias, index, enumerated, value, selected, error_list)
	if enumerated then															-- is this a test for an enumerated parameters?
		alias = alias:gsub ('#', index);										-- replace '#' with the value in index
	else
		alias = alias:gsub ('#', '');											-- remove '#' if it exists
	end

	if is_set (args[alias]) then												-- alias is in the template's argument list
		if value ~= nil and selected ~= alias then								-- if we have already selected one of the aliases
			local skip;
			for _, v in ipairs (error_list) do									-- spin through the error list to see if we've added this alias
				if v == alias then
					skip = true;
					break;														-- has been added so stop looking 
				end
			end
			if not skip then													-- has not been added so
				table.insert (error_list, alias);								-- add error alias to the error list
			end
		else
			value = args[alias];												-- not yet selected an alias, so select this one
			selected = alias;
		end
	end
	return value, selected;														-- return newly selected alias, or previously selected alias
end


--[[--------------------------< A D D _ M A I N T _ C A T >------------------------------------------------------

Adds a category to z.maint_cats_t using names from the configuration file with additional text if any.
To prevent duplication, the added_maint_cats table lists the categories by key that have been added to z.maint_cats_t.

]]

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


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

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

foreign_lang_source and foreign_lang_source_2 keys have a language code appended to them so that multiple languages
may be categorized but multiples of the same language are not categorized.

added_prop_cats is a table declared in page scope variables above

]]

local added_prop_cats = {};														-- list of property categories that have been added to z.prop_cats_t

local function add_prop_cat (key, arguments, key_modifier)
	local key_modified = key .. ((key_modifier and key_modifier) or '');		-- modify <key> with <key_modifier> if present and not nil
	
	if not added_prop_cats [key_modified] then
		added_prop_cats [key_modified] = true;									-- note that we've added this category
		table.insert (z.prop_cats_t, substitute (cfg.prop_cats [key], arguments));	-- make name then add to table
		table.insert (z.prop_keys_t, 'cs1-prop-' .. key);						-- convert key to class for use in the citation's <cite> tag
	end
end


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

Protects a string that will be wrapped in wiki italic markup '' ... ''

Note: We cannot use <i> for italics, as the expected behavior for italics specified by ''...'' in the title is that
they will be inverted (i.e. unitalicized) in the resulting references.  In addition, <i> and '' tend to interact
poorly under Mediawiki's HTML tidy.

]]

local function safe_for_italics (str)
	if not is_set (str) then return str end

	if str:sub (1, 1) == "'" then str = "<span></span>" .. str; end
	if str:sub (-1, -1) == "'" then str = str .. "<span></span>"; end
	
	return str:gsub ('\n', ' ');												-- Remove newlines as they break italics.
end


--[[--------------------------< W R A P _ S T Y L E >----------------------------------------------------------

Applies styling to various parameters.  Supplied string is wrapped using a message_list configuration taking one
argument; protects italic styled parameters.  Additional text taken from citation_config.presentation - the reason
this function is similar to but separate from wrap_msg().

]]

local function wrap_style (key, str)
	if not is_set (str) then
		return "";
	elseif in_array (key, {'italic-title', 'trans-italic-title'}) then
		str = safe_for_italics (str);
	end

	return substitute (cfg.presentation[key], {str});
end


--[[--------------------------< M A K E _ S E P _ L I S T >------------------------------------------------------------

make a separated list of items using provided separators.
	<sep_list> - typically '<comma><space>'
	<sep_list_pair> - typically '<space>and<space>'
	<sep_list_end> - typically '<comma><space>and<space>' or '<comma><space>&<space>'

defaults to cfg.presentation['sep_list'], cfg.presentation['sep_list_pair'], and cfg.presentation['sep_list_end']
if <sep_list_end> is specified, <sep_list> and <sep_list_pair> must also be supplied

]]

local function make_sep_list (count, list_seq, sep_list, sep_list_pair, sep_list_end)
	local list = '';

	if not sep_list then														-- set the defaults
		sep_list = cfg.presentation['sep_list'];
		sep_list_pair = cfg.presentation['sep_list_pair'];
		sep_list_end = cfg.presentation['sep_list_end'];
	end
	
	if 2 >= count then
		list = table.concat (list_seq, sep_list_pair);							-- insert separator between two items; returns list_seq[1] then only one item
	elseif 2 < count then
		list = table.concat (list_seq, sep_list, 1, count - 1);					-- concatenate all but last item with plain list separator
		list = table.concat ({list, list_seq[count]}, sep_list_end);			-- concatenate last item onto end of <list> with final separator
	end
	
	return list;
end


--[[--------------------------< S E L E C T _ O N E >----------------------------------------------------------

Chooses one matching parameter from a list of parameters to consider.  The list of parameters to consider is just
names.  For parameters that may be enumerated, the position of the numerator in the parameter name is identified
by the '#' so |author-last1= and |author1-last= are represented as 'author-last#' and 'author#-last'.

Because enumerated parameter |<param>1= is an alias of |<param>= we must test for both possibilities.


Generates an error if more than one match is present.

]]

local function select_one (args, aliases_list, error_condition, index)
	local value = nil;															-- the value assigned to the selected parameter
	local selected = '';														-- the name of the parameter we have chosen
	local error_list = {};

	if index ~= nil then index = tostring(index); end

	for _, alias in ipairs (aliases_list) do									-- for each alias in the aliases list
		if alias:match ('#') then												-- if this alias can be enumerated
			if '1' == index then												-- when index is 1 test for enumerated and non-enumerated aliases
				value, selected = is_alias_used (args, alias, index, false, value, selected, error_list);	-- first test for non-enumerated alias
			end
			value, selected = is_alias_used (args, alias, index, true, value, selected, error_list);	-- test for enumerated alias
		else
			value, selected = is_alias_used (args, alias, index, false, value, selected, error_list);	-- test for non-enumerated alias
		end
	end

	if #error_list > 0 and 'none' ~= error_condition then						-- for cases where this code is used outside of extract_names()
		for i, v in ipairs (error_list) do
			error_list[i] = wrap_style ('parameter', v);
		end
		table.insert (error_list, wrap_style ('parameter', selected));
		set_message (error_condition, {make_sep_list (#error_list, error_list)});
	end
	
	return value, selected;
end


--[=[-------------------------< R E M O V E _ W I K I _ L I N K >----------------------------------------------

Gets the display text from a wikilink like [[A|B]] or [[B]] gives B

The str:gsub() returns either A|B froma [[A|B]] or B from [[B]] or B from B (no wikilink markup).

In l(), l:gsub() removes the link and pipe (if they exist); the second :gsub() trims whitespace from the label
if str was wrapped in wikilink markup.  Presumably, this is because without wikimarkup in str, there is no match
in the initial gsub, the replacement function l() doesn't get called.

]=]

local function remove_wiki_link (str)
	return (str:gsub ("%[%[([^%[%]]*)%]%]", function(l)
		return l:gsub ("^[^|]*|(.*)$", "%1" ):gsub ("^%s*(.-)%s*$", "%1");
	end));
end


--[=[-------------------------< I S _ W I K I L I N K >--------------------------------------------------------

Determines if str is a wikilink, extracts, and returns the wikilink type, link text, and display text parts.
If str is a complex wikilink ([[L|D]]):
	returns wl_type 2 and D and L from [[L|D]];
if str is a simple wikilink ([[D]])
	returns wl_type 1 and D from [[D]] and L as empty string;
if not a wikilink:
	returns wl_type 0, str as D, and L as empty string.

trims leading and trailing whitespace and pipes from L and D ([[L|]] and [[|D]] are accepted by MediaWiki and
treated like [[D]]; while [[|D|]] is not accepted by MediaWiki, here, we accept it and return D without the pipes).

]=]

local function is_wikilink (str)
	local D, L
	local wl_type = 2;															-- assume that str is a complex wikilink [[L|D]]

	if not str:match ('^%[%[[^%]]+%]%]$') then									-- is str some sort of a wikilink (must have some sort of content)
		return 0, str, '';														-- not a wikilink; return wl_type as 0, str as D, and empty string as L
	end
	
	L, D = str:match ('^%[%[([^|]+)|([^%]]+)%]%]$');							-- get L and D from [[L|D]] 

	if not is_set (D) then														-- if no separate display
		D = str:match ('^%[%[([^%]]*)|*%]%]$');									-- get D from [[D]] or [[D|]]
		wl_type = 1; 
	end
	
	D = mw.text.trim (D, '%s|');												-- trim white space and pipe characters 
	return wl_type, D, L or '';
end


--[[--------------------------< S T R I P _ A P O S T R O P H E _ M A R K U P >--------------------------------

Strip wiki italic and bold markup from argument so that it doesn't contaminate COinS metadata.
This function strips common patterns of apostrophe markup.  We presume that editors who have taken the time to
markup a title have, as a result, provided valid markup. When they don't, some single apostrophes are left behind.

Returns the argument without wiki markup and a number; the number is more-or-less meaningless except as a flag
to indicate that markup was replaced; do not rely on it as an indicator of how many of any kind of markup was
removed; returns the argument and nil when no markup removed

]]

local function strip_apostrophe_markup (argument)
	if not is_set (argument) then
		return argument, nil;													-- no argument, nothing to do
	end

	if nil == argument:find ( "''", 1, true ) then								-- Is there at least one double apostrophe?  If not, exit.
		return argument, nil;
	end

	local flag;
	while true do
		if argument:find ("'''''", 1, true) then								-- bold italic (5)
			argument, flag = argument:gsub ("%'%'%'%'%'", "");					-- remove all instances of it
		elseif argument:find ("''''", 1, true) then								-- italic start and end without content (4)
			argument, flag=argument:gsub ("%'%'%'%'", "");
		elseif argument:find ("'''", 1, true) then								-- bold (3)
			argument, flag=argument:gsub ("%'%'%'", "");
		elseif argument:find ("''", 1, true) then								-- italic (2)
			argument, flag = argument:gsub ("%'%'", "");
		else
			break;
		end
	end

	return argument, flag;														-- done
end


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

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

]]

local function set_selected_modules (cfg_table_ptr)
	cfg = cfg_table_ptr;
	
end


--[[--------------------------< E X P O R T S >----------------------------------------------------------------
]]

return {
	add_maint_cat = add_maint_cat,												-- exported functions
	add_prop_cat = add_prop_cat,
	error_comment = error_comment,
	has_accept_as_written = has_accept_as_written,
	hyphen_to_dash = hyphen_to_dash,
	in_array = in_array,
	is_set = is_set,
	is_wikilink = is_wikilink,
	make_sep_list = make_sep_list,
	make_wikilink = make_wikilink,
	remove_wiki_link = remove_wiki_link,
	safe_for_italics = safe_for_italics,
	select_one = select_one,
	set_message = set_message,
	set_selected_modules = set_selected_modules,
	strip_apostrophe_markup = strip_apostrophe_markup,
	substitute = substitute,
	wrap_style = wrap_style,

	z = z,																		-- exported table
	}