Module:Lang

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

--[=[

Lua support for the {{Lang}}, {{Lang-xx}}, and {{Transl}} templates and 
support for other templates and modules.

]=]

require('Module:No globals')

local getArgs = require('Module:Arguments').getArgs
local unicode = require("Module:Unicode data")									-- for is_latin() and is_rtl()

local lang_data = mw.loadData('Module:Lang/data')								-- language name override and transliteration tool-tip tables
local lang_name_table = lang_data.lang_name_table								-- language codes, names, regions, scripts, suppressed scripts
local lang_table = lang_data.lang_name_table.lang
local lang_dep_table = lang_data.lang_name_table.lang_dep
local script_table = lang_data.lang_name_table.script
local override_table = lang_data.override

local namespace = mw.title.getCurrentTitle().namespace							-- used for categorization

local maintenance_categories = {}												-- maintenance categories go here
local maintenance_messages = {}													-- and their messages go here

local tracking_categories = {
	["CATEGORY_LANG_DEPRECATED"] = "Category:Lang and lang-xx using deprecated ISO 639 codes|%s",
	["CATEGORY_LANG_PROMOTED"] = "Category:Lang and lang-xx code promoted to ISO 639-1|%s",
	["ERROR_CATEGORY"] = "[[Category:%s template errors]]",
}

local language_categories = {
	["ENGLISH_TEXT"] = "[[Category:Articles containing explicitly cited %s-language text]]",
	["LANGUAGE_TEXT"] = "[[Category:Articles containing %s-language text]]",
	["LANGUAGES_COLLECTIVE_TEXT"] = "[[Category:Articles with text in %s]]",
}

local error_messages = {
	["CODE_DEPRECATED"] = "code: %s is deprecated",
	["CODE_PROMOTED"] = "code: %s promoted to code: %s",
	["CONFLICTING_LIT_TRANSLATION"] = "conflicting: {{{3}}} and |lit= or |translation=",
	["CONFLICTING_NAMED_AND_NAMED"] = "conflicting: |%s= and |%s=",
	["CONFLICTING_POSITIONAL_AND_NAMED"] = "conflicting: {{{%s}}} and |%s=",
	["INVALID_PROTO"] = "invalid |proto=",
	["INVALID_TRANSLIT_STD_VALUE"] = "invalid |translit-std=: %s",
	["MISSING_LANGUAGE_OR_SCRIPT_CODE"] = "missing language / script code",
	["MISSING_LANGUAGE_TAG"] = "missing language tag",
	["LANGUAGE_NOT_FOUND"] = "language: %s not found",
	["LANGUAGE_NOT_PROVIDED"] = "missing language name",
	["NO_TEXT"] = "no text",
	["ONLY_ONE_TYPE_ITALICS"] = "only one of |italic=, |italics=, or |i= can be specified",
	["REDUNDANT_REGION_TAG"] = "redundant region tag",
	["REDUNDANT_SCRIPT_TAG"] = "redundant script tag",
	["REDUNDANT_VARIANT_TAG"] = "redundant variant tag",
	["SCRIPT_NOT_SUPPOTED_FOR_CODE"] = "script: %s not supported for code: %s",
	["TEXT_HAS_MALFORMED_MARKUP"] = "text has malformed markup",
	["TEXT_HAS_ITALIC_MARKUP"] = "text has italic markup",
	["UNRECOGNIZED_LANGUAGE_OR_SCRIPT_CODE"] = "unrecognized language / script code: %s",
	["UNRECOGNIZED_TRANSLITERATION_STANDARD"] = "unrecognized transliteration standard: %s",
	["UNRECOGNIZED_LANGUAGE_CODE"] = "unrecognized language code: %s",
	["UNRECOGNIZED_LANGUAGE_TAG"] = "unrecognized language tag: %s",
	["UNRECOGNIZED_PRIVATE_TAG"] = "unrecognized private tag: %s",
	["UNRECOGNIZED_VARIANT"] = "unrecognized variant: %s",
	["UNRECOGNIZED_SCRIPT_FOR_CODE"] = "unrecognized script: %s for code: %s",
	["UNRECOGNIZED_REGION_FOR_CODE"] = "unrecognized region: %s for code: %s",
	["UNRECOGNIZED_VARIANT_FOR_CODE"] = "unrecognized variant: %s for code: %s",
	["UNRECOGNIZED_VARIANT_FOR_CODE_SCRIPT_PAIR"] = "unrecognized variant: %s for code-script pair: %s-%s",
	["UNRECOGNIZED_VARIANT_FOR_CODE_REGION_PAIR"] = "unrecognized variant: %s for code-region pair: %s-%s",
}

local strings = {
	-- Template names --
	["TEMPLATE_LANG_LANG_XX"] = "Lang and lang-xx",
	["TEMPLATE_LANG"] = "Lang",
	["TEMPLATE_LANG_XX"] = "Lang-xx",
	["TEMPLATE_TRANSL"] = "Transl",

	-- Error --
	["ERROR_SPAN"] = '[%s] <span style="font-size: 100%%; font-style: normal;" class="error">Error: {{%s}}: %s ([[:Category:%s template errors|help]])</span>',
	["UNDEFINED"] = "undefined",

	-- Maintenance --
	["MAINTENANCE_SPAN"] = '<span class="lang-comment" style="font-style: normal; display: none; color: #33aa33; margin-left: 0.3em;">%s</span>',

	-- Lang_xx --
	["LABEL_LANGUAGE"] = "%s: %s",
	["LABEL_TRANSLATION"] = ', <small>%s&nbsp;</small>&#39;%s&#39;',			-- use HTML entities to avoid wiki markup confusion
	["LABEL_TRANSLIT"] = ", <small>%s:&nbsp;</small>%s",
	["LIT"] = "lit.",
	["LITERAL_TRANSLATION_ABBR"] = '<abbr title="literal translation">lit.</abbr>',
	["LITERAL_TRANSLATION_TEXT"] = "Literal translation",
	["ROMANIZATION_OF"] = "Romanization of %s",
	["ROMANIZED"] = "romanized",

	-- HTML lang --
	["HTML_LANG_TAG"] = '%s<%s lang="%s" %s style="%s %s" %s>%s</%s>%s',
	["ASTERISK"] = "&#42;",														-- use numeric entity because plain asterisk confuses MediaWiki
	["DIR_ATTRIBUTE"] = 'dir="rtl"',
	["FONT_STYLE"] = "font-style: normal;",
	["FONT_SIZE"] = "font-size: %s;",
	["LTR_MARK"] = "&lrm;",
	["TITLE_ATTRIBUTE_COLLECTIVE"] = 'title="%s collective text"',
	["TITLE_ATTRIBUTE_LANGUAGE"] = 'title="%s language text"',

	-- Transliteration --
	["TRANSLIT_ITALIC"] = '<i lang="%s-Latn" title="%s">%s</i>',
	["TRANSLIT_SPAN_CODE"] = '<span style="font-style: %s" lang="%s-Latn" title="%s">%s</span>',
	["TRANSLIT_SPAN_NO_CODE"] = '<span title="%s">%s</span>',
	["TRANSLITERATION_STD_SCRIPT"] = "%s (%s script) transliteration",
	["TRANSLITERATION_STD_LANGUAGE"] = "%s (%s language) transliteration",
	["TRANSLITERATION_SCRIPT"] = "%s-script transliteration",
	["TRANSLITERATION_LANGUAGES"] = "%s transliteration",
	["TRANSLITERATION_LANGUAGE"] = "%s-language transliteration",
	["ROMANIZATION_LANGUAGES"] = "%s romanization",
	["ROMANIZATION_LANGUAGE"] = "%s-language romanization",
}


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

This function attempts to invert the italic markup in args.text
by adding or removing leading and trailing italic markup in args.text.

Like |italic=unset, |italic=invert disables automatic italic markup.

Individual leading and trailing apostrophes are converted to their HTML numeric entity
equivalent so that the new italic markup doesn't become bold markup inadvertently.

Leading and trailing wiki markup is extracted from args.text into separate table elements.
Addition, removal, replacement of wiki markup is handled by a string.gsub()
replacement table operating only on these separate elements.

In the string.gsub() matching pattern, '.*' matches empty string as well as
the three expected wiki markup patterns.

This function expects that markup in args.text is complete and correct;
if it is not, oddness may result.

]]

local function invert_italics(source)
	source = source:gsub("%f[\']\'%f[^\']", '&#39;')							-- protect single quote marks from being interpreted as bold markup

	local seg = {}
	seg[1] = source:match('^(\'\'+%f[^\']).+') or ''							-- get leading markup, if any; ignore single quote
	seg[3] = source:match('.+(%f[\']\'\'+)$') or ''								-- get trailing markup, if any; ignore single quote

	if seg[1] ~= '' and seg[3] ~= '' then										-- extract the 'text' 
		seg[2] = source:match('^\'\'+%f[^\'](.+)%f[\']\'\'+$')					-- from between leading and trailing markup
	elseif seg[1] ~= '' then
		seg[2] = source:match('^\'\'+%f[^\'](.+)')								-- following leading markup
	elseif seg[3] ~= '' then
		seg[2] = source:match('(.+)%f[\']\'\'+$')								-- preceding trailing markup
	else
		seg[2] = source															-- when there is no markup
	end

	local invert_pattern_table = {												-- leading/trailing markup add/remove/replace patterns
		[""] = "\'\'",															-- empty string becomes italic markup
		["\'\'"] = "",															-- italic markup becomes empty string
		["\'\'\'"] = "\'\'\'\'\'",												-- bold becomes bold italic
		["\'\'\'\'\'"] = "\'\'\'",												-- bold italic become bold
	}

	seg[1] = invert_pattern_table[seg[1]] or seg[1]								-- replace leading markup according to pattern table
	seg[3] = invert_pattern_table[seg[3]] or seg[3]								-- replace leading markup according to pattern table

	return table.concat(seg)													-- put it all back together and done
end


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

Validates |italic= or |italics= assigned values.

When |italic= is set and has an acceptable assigned value,
return the matching css font-style property value or,
for the special case 'default', return nil.

When |italic= is not set, or has an unacceptible assigned value,
return nil and a nil error message.

When both |italic= and |italics= are set, returns nil
and a 'conflicting' error message.

The return value nil causes the calling lang, lang_xx, or transl function to set
args.italic according to the template's defined default
('inherit' for {{Lang}}, 'inherit' or 'italic' for {{Lang-xx}} depending on
the individual template's requirements, 'italic' for {{Transl}})
or to the value appropriate to |script=, if set ({{Lang}} and {{Lang-xx}} only).

Accepted values and the values that this function returns are are:
	nil		-	when |italic= absent or not set; returns nil
	default	-	for completeness, should rarely if ever be used; returns nil
	yes		-	force args.text to be rendered in italic font; returns 'italic'
	no		-	force args.text to be rendered in normal font; returns 'normal'
	unset	-	disables font control so that font-style applied to text is dictated by markup inside or outside the template; returns 'inherit'
	invert	-	disables font control so that font-style applied to text is dictated by markup outside or inverted inside the template; returns 'invert'

]]

local function validate_italic(args)
	local count = 0
	for _, arg in pairs{'italic', 'italics', 'i'} do
		if args[arg] then
			count = count + 1
		end
	end

	if count > 1 then															-- return nil and an error message if more than one is set 
		return nil, error_messages["ONLY_ONE_TYPE_ITALICS"]
	end

	local properties = {
		['yes'] = 'italic',
		['no'] = 'normal',
		['unset'] = 'inherit',
		['invert'] = 'invert',
		['default'] = nil,
	}

	return properties[args.italic or args.italics or args.i], nil				-- return an appropriate value and a nil error message
end


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

Default behavior of the {{Lang}} and {{Lang-xx}} templates is to add categorization when the templates are used in mainspace.
This default functionality may be suppressed by setting |nocat=yes or |cat=no. This function selects one of these two parameters
to control categorization.

Because having two parameters with 'opposite' names and 'opposite' values is confusing, this function accepts only affirmative
values for |nocat= and only negative values for |cat=; in both cases the 'other' sense (and non-sense) is not accepted and the
parameter is treated as if it were not set in the template.

Sets args.nocat to true if categorization is to be turned off; to nil if the default behavior should apply.

Accepted values for |nocat= are the text strings:
	'yes', 'y', 'true', 't', on, '1'		-- [[Module:Yesno]] returns logical true for all of these; false or nil else
for |cat=
	'no', 'n', 'false', 'f', 'off', '0'		-- [[Module:Yesno]] returns logical false for all of these; true or nil else

]=]

local function validate_cat_args(args)
	if not (args.nocat or args.cat) then										-- both are nil, so categorize
		return
	end

	local yesno = require('Module:Yesno')
	if yesno(args.cat) == false or yesno(args.nocat) == true then
		args.nocat = true														-- set to true when args.nocat is affirmative; nil else (as if the parameter were not set in the template)
	else																		-- args.nocat is the parameter actually used.
		args.nocat = nil
	end
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


--[[ -------------------------- < F O R M A T _ I E T F _ T A G > --------------------------

Prettify IETF tags to use recommended subtag formats:
	code: lower case
	script: sentence case
	region: upper case
	variant: lower case
	private: lower case prefixed with -x-

]]

local function format_ietf_tag(code, script, region, variant, private)
	local out = {}

	if is_set(private) then
		return string.format("%s-x-%s", code:lower(), private:lower())			-- if private, all other tags ignored
	end
	
	table.insert(out, code:lower())
	if is_set(script) then
		script = script:lower():gsub('^%a', string.upper)
		table.insert(out, script)
	end

	if is_set(region) then
		table.insert(out, region:upper())
	end

	if is_set(variant) then
		table.insert(out, variant:lower())
	end

	return table.concat(out, '-')
end


--[[ -------------------------- < G E T _ I E T F _ P A R T S > --------------------------

Extracts and returns IETF language tag parts:
	primary language subtag (required) - 2 or 3 character IANA language code
	script subtag - four character IANA script code
	region subtag - two-letter or three digit IANA region code
	variant subtag - four digit or 5-8 alnum variant code; only one variant subtag supported
	private subtag - x- followed by 1-8 alnum private code; only supported with the primary language tag

Supported forms:
	lang					lang-variant
	lang-script				lang-script-variant
	lang-region				lang-region-variant
	lang-script-region		lang-script-region-variant
	lang-x-private	

Each of lang, script, region, variant, and private, when used, must be valid.

Languages with both two- and three-character code synonyms are promoted to the two-character synonym because
the IANA registry file omits the synonymous three-character code; we cannot depend on browsers understanding
the synonymous three-character codes in the lang= attribute.

For {{Lang-xx}} templates, the parameters |script=, |region=, and |variant= are supported (not supported in {{Lang}}
because those parameters are superfluous to the IETF subtags in |code=).

Returns six values; all lower case. Valid parts are returned as themselves; omitted parts are returned as empty strings, invalid
parts are returned as nil; the sixth returned item is an error message (if an error detected) or nil.

See http://www.rfc-editor.org/rfc/bcp/bcp47.txt section 2.1

]]

local function get_ietf_parts(source, args_script, args_region, args_variant)
	if not is_set(source) then
		return nil, nil, nil, nil, nil, error_messages["MISSING_LANGUAGE_TAG"]
	end

	local pattern = {															-- table of tables holding acceptable IETF tag patterns and short names of the IETF part captured by the pattern
		{'^(%a%a%a?)%-(%a%a%a%a)%-(%a%a)%-(%d%d%d%d)$', 's', 'r', 'v'}, 				-- 1 -	ll-Ssss-RR-variant (where variant is 4 digits)
		{'^(%a%a%a?)%-(%a%a%a%a)%-(%d%d%d)%-(%d%d%d%d)$', 's', 'r', 'v'},				-- 2 -	ll-Ssss-DDD-variant (where region is 3 digits and variant is 4 digits)
		{'^(%a%a%a?)%-(%a%a%a%a)%-(%a%a)%-(%w%w%w%w%w%w?%w?%w?)$', 's', 'r', 'v'},		-- 3 -	ll-Ssss-RR-variant (where variant is 5-8 alnum characters)
		{'^(%a%a%a?)%-(%a%a%a%a)%-(%d%d%d)%-(%w%w%w%w%w%w?%w?%w?)$', 's', 'r', 'v'},	-- 4 -	ll-Ssss-DDD-variant (where region is 3 digits and variant is 5-8 alnum characters)

		{'^(%a%a%a?)%-(%a%a%a%a)%-(%d%d%d%d)$', 's', 'v'},						-- 5 -	ll-Ssss-variant (where variant is 4 digits)
		{'^(%a%a%a?)%-(%a%a%a%a)%-(%w%w%w%w%w%w?%w?%w?)$', 's', 'v'},			-- 6 -	ll-Ssss-variant (where variant is 5-8 alnum characters)

		{'^(%a%a%a?)%-(%a%a)%-(%d%d%d%d)$', 'r', 'v'},							-- 7 -	ll-RR-variant (where variant is 4 digits)
		{'^(%a%a%a?)%-(%d%d%d)%-(%d%d%d%d)$', 'r', 'v'},						-- 8 -	ll-DDD-variant (where region is 3 digits and variant is 4 digits)
		{'^(%a%a%a?)%-(%a%a)%-(%w%w%w%w%w%w?%w?%w?)$', 'r', 'v'},				-- 9 -	ll-RR-variant (where variant is 5-8 alnum characters)
		{'^(%a%a%a?)%-(%d%d%d)%-(%w%w%w%w%w%w?%w?%w?)$', 'r', 'v'},				-- 10 - ll-DDD-variant (where region is 3 digits and variant is 5-8 alnum characters)

		{'^(%a%a%a?)%-(%d%d%d%d)$', 'v'},										-- 11 - ll-variant (where variant is 4 digits)
		{'^(%a%a%a?)%-(%w%w%w%w%w%w?%w?%w?)$', 'v'},							-- 12 - ll-variant (where variant is 5-8 alnum characters)

		{'^(%a%a%a?)%-(%a%a%a%a)%-(%a%a)$', 's', 'r'},							-- 13 - ll-Ssss-RR
		{'^(%a%a%a?)%-(%a%a%a%a)%-(%d%d%d)$', 's', 'r'},						-- 14 - ll-Ssss-DDD (region is 3 digits)

		{'^(%a%a%a?)%-(%a%a%a%a)$', 's'},										-- 15 - ll-Ssss

		{'^(%a%a%a?)%-(%a%a)$', 'r'},											-- 16 - ll-RR
		{'^(%a%a%a?)%-(%d%d%d)$', 'r'},											-- 17 - ll-DDD (region is 3 digits)

		{'^(%a%a%a?)$'},														-- 18 - ll

		{'^(%a%a%a?)%-x%-(%w%w?%w?%w?%w?%w?%w?%w?)$', 'p'},						-- 19 - ll-x-pppppppp (private is 1-8 alnum characters)
	}

	local t = {}																-- table of captures; serves as a translator between captured IETF tag parts and named variables
	local code, script, region, variant, private								-- IETF tag parts
	for i, v in ipairs(pattern) do												-- spin through the pattern table looking for a match
		local c1, c2, c3, c4													-- captures in the 'pattern' from the pattern table go here

		c1, c2, c3, c4 = source:match(pattern[i][1])							-- one or more captures set if source matches pattern[i])
		if c1 then																-- c1 always set on match
			code = c1															-- first capture is always code
			t = {
				[pattern[i][2] or 'x'] = c2,									-- fill the table of captures with the rest of the captures
				[pattern[i][3] or 'x'] = c3,									-- take index names from pattern table and assign sequential captures
				[pattern[i][4] or 'x'] = c4,									-- index name may be nil in pattern[i] table so "or 'x'" spoofs a name for this index in this table
			}
			script = t.s or ''													-- translate table contents to named variables;
			region = t.r or ''													-- absent table entries are nil so set named IETF parts to empty string for concatenation
			variant = t.v or ''
			private = t.p or ''
			break																-- and done
		end
	end

	if not code then
		return nil, nil, nil, nil, nil, string.format(error_messages["UNRECOGNIZED_LANGUAGE_TAG"], source)	-- don't know what we got but it is malformed
	end

	code = code:lower()															-- ensure that we use and return lower case version of this

	local synonym_table = mw.loadData('Module:Lang/ISO 639 synonyms')			-- ISO 639-2/639-2T code translation to 639-1 code

	if not (override_table[code] or lang_table[code] or synonym_table[code] or lang_dep_table[code]) then
		return nil, nil, nil, nil, nil, string.format(error_messages["UNRECOGNIZED_LANGUAGE_CODE"], code)	-- invalid language code, don't know about the others (don't care?)
	end

	if synonym_table[code] then													-- if 639-2/639-2T code has a 639-1 synonym
		table.insert(maintenance_categories, string.format(tracking_categories["CATEGORY_LANG_PROMOTED"], code))
		table.insert(maintenance_messages, string.format(error_messages["CODE_PROMOTED"], code, synonym_table[code]))
		code = synonym_table[code]												-- use the synonym
	end

	if is_set(script) then
		if is_set(args_script) then
			return code, nil, nil, nil, nil, error_messages["REDUNDANT_SCRIPT_TAG"]	-- both code with script and |script= not allowed
		end
	else
		script = args_script or ''												-- use args.script if provided
	end 

	if is_set(script) then
		script = script:lower()													-- ensure that we use and return lower case version of this
		if not script_table[script] then
			return code, nil, nil, nil, nil, string.format(error_messages["UNRECOGNIZED_SCRIPT_FOR_CODE"], script, code)	-- language code ok, invalid script, don't know about the others (don't care?)
		end
	end

	local suppressed_table = lang_data.lang_name_table.suppressed
	if suppressed_table[script] then											-- ensure that code-script does not use a suppressed script
		if in_array(code, suppressed_table[script]) then
			return code, nil, nil, nil, nil, string.format(error_messages["SCRIPT_NOT_SUPPOTED_FOR_CODE"], script, code)	-- language code ok, script is suppressed for this code
		end
	end

	if is_set(region) then
		if is_set(args_region) then
			return code, script, nil, nil, nil, error_messages["REDUNDANT_REGION_TAG"]	-- both code with region and |region= not allowed
		end
	else
		region = args_region or ''												-- use args.region if provided
	end 

	if is_set(region) then
		region = region:lower()													-- ensure that we use and return lower case version of this
		local region_table = lang_data.lang_name_table.region
		if not region_table[region] then
			return code, script, nil, nil, nil, string.format(error_messages["UNRECOGNIZED_REGION_FOR_CODE"], region, code)
		end
	end

	if is_set(variant) then
		if is_set(args_variant) then
			return code, script, region, nil, nil, error_messages["REDUNDANT_VARIANT_TAG"]	-- both code with variant and |variant= not allowed
		end
	else
		variant = args_variant or ''											-- use args.variant if provided
	end 

	if is_set(variant) then
		variant = variant:lower()												-- ensure that we use and return lower case version of this
		local variant_table = lang_data.lang_name_table.variant

		if not variant_table[variant] then										-- make sure variant is valid
			return code, script, region, nil, nil, string.format(error_messages["UNRECOGNIZED_VARIANT"], variant)
		end																		-- does this duplicate/replace tests in lang() and lang_xx()?

		if is_set(script) then													-- if script set it must be part of the 'prefix'
			if not in_array(string.format("%s-%s", code, script), variant_table[variant]['prefixes']) then
				return code, script, region, nil, nil, string.format(error_messages["UNRECOGNIZED_VARIANT_FOR_CODE_SCRIPT_PAIR"], variant, code, script)
			end
		elseif is_set(region) then												-- if region set, there are some prefixes that require lang code and region (en-CA-newfound)
			if not in_array(code, variant_table[variant]['prefixes']) then		-- first see if lang code is all that's required (en-oxendict though en-GB-oxendict is preferred)
				if not in_array(string.format("%s-%s", code, region), variant_table[variant]['prefixes']) then		-- now try for lang code and region (en-CA-newfound)
					return code, script, region, nil, nil, string.format(error_messages["UNRECOGNIZED_VARIANT_FOR_CODE_REGION_PAIR"], variant, code, region)
				end
			end
		else
			if not in_array(code, variant_table[variant]['prefixes']) then
				return code, script, region, nil, nil, string.format(error_messages["UNRECOGNIZED_VARIANT_FOR_CODE"], variant, code)
			end
		end
	end

	if is_set(private) then
		private = private:lower()												-- ensure that we use and return lower case version of this
		if not override_table[string.format("%s-x-%s", code, private)] then		-- make sure private tag is valid; note that index 
			return code, script, region, variant, nil, string.format(error_messages["UNRECOGNIZED_PRIVATE_TAG"], private)
		end
	end
	return code, script, region, variant, private, nil							-- return the good bits; make sure that msg is nil
end


--[[ -------------------------- < M A K E _ E R R O R _ M S G > --------------------------

Assembles an error message from template name, message text,
help link, and error category.

]]

local function make_error_msg(msg, args, template)
	local out = {}

	local category
	if template == strings["TEMPLATE_TRANSL"] then
		category = strings["TEMPLATE_TRANSL"]
	else
		category = strings["TEMPLATE_LANG_LANG_XX"]
	end

	if template then
		table.insert(out, string.format(strings["ERROR_SPAN"], args.text or strings["UNDEFINED"], template, msg, category))
	else
		local error_text = string.format(strings["ERROR_SPAN"], "", "", msg, category)
		error_text = error_text:gsub("%[] ", ""):gsub("{{}}: ", "")
		table.insert(out, error_text)
	end

	if (namespace == 0) and not args.nocat then									-- only categorize in article space
		table.insert(out, string.format(tracking_categories["ERROR_CATEGORY"], category))
	end

	return table.concat(out)
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, 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 is_set(link) then
		if is_set(display) then
			return string.format("[[%s|%s]]", link, display)
		else
			return string.format("[[%s]]", link)
		end
	else
		return ''
	end
end


--[[ -------------------------- < D I V _ M A R K U P _ A D D > --------------------------

Adds <i> and </i> tags to list-item text or to implied <p>..</p> text.
Mixed not supported.

]]

local function div_markup_add(text, style)
local implied_p = {}

	if text:find('^\n[%*:;#]') then												-- look for list markup; list markup must begin at start of text
		if style == 'italic' then
			return mw.ustring.gsub(text, '(\n[%*:;#]+)([^\n]+)', '%1<i>%2</i>')	-- insert <i> tags at each list item
		else
			return text
		end
	end

	if text:find('\n+') then													-- look for any number of \n characters in text
		text = text:gsub('([^\n])\n([^\n])', '%1 %2')							-- replace single newline characters with a space character which mimics MediaWiki

		if style == 'italic' then
			text = text:gsub('[^\n]+', '<p><i>%1</i></p>')						-- insert <p> and <i> tags at each implied <p> (two or more consecutive '\n\n' sequences)
		else
			text = text:gsub('[^\n]+', '<p>%1</p>')								-- insert <p> markup at each implied <p>
			text = text:gsub('\n', '')											-- strip newline characters
		end
	end

	return text
end


--[[ -------------------------- < M A K E _ T E X T _ H T M L > --------------------------

Add the HTML markup to text according to the type of content that it is:
<span> or <i> tags for inline content or <div> tags for block content.

]]

local function make_text_html(code, text, tag, rtl, style, size, language)
	local asterisk = ""
	if text:match('^%*') then
		asterisk = strings["ASTERISK"]											-- move proto language text prefix outside of italic markup if any
		text = text:gsub('^%*', '')												-- remove the asterisk from the text
	end

	if tag == 'span' then														-- default HTML tag for inline content
		if style == 'italic' then												-- but if italic
			tag = 'i'															-- change to <i> tags
		end
	else																		-- must be <div> so go
		text = div_markup_add(text, style)										-- handle implied <p>, implied <p> with <i>, and list markup (*;:#) with <i>
	end

	local ltr = ""
	local dir_attribute = ""
	if rtl or unicode.is_rtl(text) then
		dir_attribute = strings["DIR_ATTRIBUTE"]								-- add direction attribute for right to left languages
		ltr = strings["LTR_MARK"]												-- legacy; shouldn't be necessary because all of the rtl text is wrapped inside an HTML tag with dir="rtl" attribute 
																				-- make sure the browser knows that we're at the end of the rtl
	end

	local font_style = ""
	if style == 'normal' then													-- when |italic=no
		font_style = strings["FONT_STYLE"]										-- override external markup, if any
	end

	local font_size = ""
	if is_set(size) then														-- when |size=<something>
		font_size = string.format(strings["FONT_SIZE"], size)
	end

	local title_attribute = ""
	if is_set(language) then
		if language:find('languages') then
			title_attribute = string.format(strings["TITLE_ATTRIBUTE_COLLECTIVE"], language) -- for collective languages
		else
			title_attribute = string.format(strings["TITLE_ATTRIBUTE_LANGUAGE"], language)	-- for individual languages
		end
	end

	local html = string.format(strings["HTML_LANG_TAG"], asterisk, tag, code, dir_attribute, font_style, font_size, title_attribute, text, tag, ltr)
	-- Prettify output
	html = html:gsub('style=" "', ""):gsub("%s+", " "):gsub(" >", ">"):gsub(' "', '"')	-- remove empty style="" attribute; extra spaces for a cleaner tag; space before closing tag or double quote
	return html
end


--[=[ -------------------------- < M A K E _ C A T E G O R Y > --------------------------

For individual language, <language>, returns:
	[[Category:Articles containing <language>-language text]]

for English:
	[[Category:Articles containing explicitly cited English-language text]]
	
for ISO 639-2 collective languages (and for 639-1 bh):
	[[Category:Articles with text in <language> languages]]

]=]

local function make_category(code, language_name, nocat, name_get)
	if ((namespace ~= 0) or nocat) and not name_get then						-- only categorize in article space
		return ''																-- return empty string for concatenation
	end

	if language_name:find('languages') then
		return string.format(language_categories["LANGUAGES_COLLECTIVE_TEXT"], language_name)
	end

	if code == 'en' then
		return string.format(language_categories["ENGLISH_TEXT"], language_name)	-- falls back to English if regional name not available
	else
		return string.format(language_categories["LANGUAGE_TEXT"], language_name)
	end
end


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

Return translit <i lang=xx-Latn>...</i> where xx is the language code;
else return empty string.

The value |script= is not used in {{Transl}} for this purpose; instead it uses |code.
Because language scripts are listed in the {{Transl}} switches they are included in the data tables.
The script parameter is introduced at {{Language with name and transliteration}}.
If |script= is set, this function uses it in preference to code.

To avoid confusion, in this module and the templates that use it, the transliteration script parameter is renamed
to be |translit-script= (in this function, tscript).

This function is used by both lang_xx() and transl()
	lang_xx() always provides code, language_name, and translit; may provide tscript; never provides style
	transl() always provides language_name, translit, and one of code or tscript, never both; always provides style

For {{transl}}, style only applies when a language code is provided.
]]

local function make_translit(code, language_name, translit, std, tscript, style)
	local title_table = lang_data.translit_title_table							-- table of transliteration standards and the language codes and scripts that apply to those standards
	std = std and std:lower()													-- lower case for table indexing
	local title_attribute

	if is_set(std) then
		if not title_table[std] then											-- invalid standard, setup for error message
			return ''
		end

		if title_table[std][tscript] and script_table[tscript] then				-- and if script for that standard is legitimate
			title_attribute = string.format(strings["TRANSLITERATION_STD_SCRIPT"], title_table[std][tscript:lower()], script_table[tscript][1])	-- add the appropriate text to the tool tip
		elseif title_table[std][code] then										-- if language code is in the table (transl may not provide a language code)
			title_attribute = string.format(strings["TRANSLITERATION_STD_LANGUAGE"],title_table[std][code:lower()], language_name)	-- add the appropriate text to the tool tip
		else
			title_attribute = title_table[std]['default']						-- use the default if script not in std table
		end
	elseif title_table['no_std'][tscript] then
		title_attribute = title_table['no_std'][tscript]						-- use translit-script if set
	elseif title_table['no_std'][code] then
		title_attribute = title_table['no_std'][code]							-- use language code
	elseif is_set(tscript) then
		title_attribute = string.format(strings["TRANSLITERATION_SCRIPT"], language_name)	-- write a script tool tip
-- TODO: Conflicting with next section. Commenting out for now.
--	elseif is_set(code) then
--		if language_name:find('languages') then									-- collective language names (plural 'languages' is part of the name)
--			title_attribute = string.format(strings["TRANSLITERATION_LANGUAGES"], language_name)
--		else																	-- individual and macro languages only
--			title_attribute = string.format(strings["TRANSLITERATION_LANGUAGE"], language_name)
--		end
	else																		-- when neither standard nor script specified
		if language_name:find('languages') then									-- collective language names (plural 'languages' is part of the name)
			title_attribute = string.format(strings["ROMANIZATION_LANGUAGES"], language_name)
		else																	-- individual and macro languages only
			title_attribute = string.format(strings["ROMANIZATION_LANGUAGE"], language_name)
		end
	end

	if is_set(code) then														-- when a language code is provided (always with {{Lang-xx}} templates, not always with {{Transl}})
		if style then
			return string.format(strings["TRANSLIT_SPAN_CODE"], style, code, title_attribute, translit) -- non-standard style, construct a <span> tag for it
		else																	-- nil for the default italic style
			return string.format(strings["TRANSLIT_ITALIC"], code, title_attribute, translit)	-- so use <i> tag
		end
	else
		return string.format(strings["TRANSLIT_SPAN_NO_CODE"], title_attribute, translit)	-- when no language code: no lang= attribute, not italic ({{Transl}} only)
	end
end


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

This function checks the content of args.text and returns empty string if nothing is amiss else it returns an
error message. The tests are for empty or missing text and for improper or disallowed use of apostrophe markup.

Italic rendering is controlled by the |italic= template parameter so italic markup should never appear in args.text
either as ''itself'' or as '''''bold italic''''' unless |italic=unset or |italic=invert.

]]

local function validate_text(template, args)
	if not is_set(args.text) then
		return make_error_msg(error_messages["NO_TEXT"], args, template)
	end

	if args.text:find("%f[\']\'\'\'\'%f[^\']") or args.text:find("\'\'\'\'\'[\']+") then	-- because we're looking, look for 4 apostrophes or 6+ apostrophes
		return make_error_msg(error_messages["TEXT_HAS_MALFORMED_MARKUP"], args, template)
	end

	local style = args.italic
	if (style ~= 'unset') and (style ~= 'invert') then
		if args.text:find("%f[\']\'\'%f[^\']") or args.text:find("%f[\']\'\'\'\'\'%f[^\']") then	-- italic but not bold, or bold italic
			return make_error_msg(error_messages["TEXT_HAS_ITALIC_MARKUP"], args, template)
		end
	end
end


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

Render maintenance messages and categories.

]]

local function render_maintenance(nocat)
	local maintenance = {}

	if 0 < #maintenance_messages then	
		table.insert(maintenance, string.format(strings["MAINTENANCE_SPAN"], table.concat(maintenance_messages, " ")))
	end

	if (0 < #maintenance_categories) and (namespace == 0) and not nocat then	-- when there are maintenance categories; article namespace only
		for _, category in ipairs(maintenance_categories) do
			table.insert(maintenance, string.format("[[%s]]", category))		-- format and add the categories
		end
	end

	return table.concat(maintenance)
end


--[[ -------------------------- < P R O T O _ P R E F I X > --------------------------

For proto languages, text is prefixed with an asterisk.
We do that here as a flag for make_text_html() so that an asterisk will be
rendered outside of italic markup (if used).
If the first character in text here is already an asterisk, we do nothing.

proto_param is boolean or nil:
- true adds asterisk prefix regardless of language name.
- false removes and / or inhibits regardless of language name.
- nil does nothing; presumes that the value in text is correct but removes extra asterisk.

]]

local function proto_prefix(text, language_name, proto_param)
	if proto_param == false then												-- when forced by |proto=no
		return text:gsub('^%**', '')											-- return text without asterisk prefix regardless of language name or existing asterisk prefix in text
	elseif (language_name:find('^Proto%-') or (true == proto_param)) then		-- language is a proto or forced by |proto=yes
		return text:gsub('^%**', '*')											-- prefix proto-language text with an asterisk; also removes duplicate prefixing asterisks
	end

	return text:gsub('^%*+', '*')												-- return text unmolested except multiple asterisks reduced to one asterisk
end


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

Looks for a <poem> strip marker in text; returns true when found; false else.

Auto-italic detection disabled when text has <poem> strip marker because it is not possible for this code to know
the content that will replace the strip marker.

]]

local function has_poem_tag(text)
	return text:find('\127[^\127]*UNIQ%-%-poem%-[%a%d]+%-QINU[^\127]*\127') and true or false
end


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

Inspects content of and selectively trims text.
Returns text and the name of an appropriate HTML tag for text.

If text contains:
	\n\n	text has implied <p>..</p> tags - trim leading and trailing whitespace and return 
If text begins with list markup:
	\n*		unordered
	\n;		definition
	\n:		definition
	\n#		ordered
trim all leading whitespace except \n and trim all trailing whitespace

If text contains <poem>...</poem> strip marker, return text unmodified and choose <div>..</div> tags because 
the strip marker is replaced with text wrapped in <div>..</div> tags.

]]

local function html_tag_select(text)
	local tag

	if has_poem_tag(text) then													-- contains <poem> strip marker (we can't know the content of that)
		tag = 'div'																-- <poem> replacement is in <div> tags so lang must use <div> tags
	elseif mw.text.trim(text):find('\n\n+') then								-- contains implied <p> tags
		text = mw.text.trim(text)												-- trim leading and trailing whitespace characters
		tag = 'div'																-- must be <div> because <span> may not contain <p> tags (added later by MediaWiki); <poem> replacement is in <div> tags
	elseif text:find('\n[%*:;%#]') then											-- if text has list markup
		text = text:gsub('^[\t\r\f ]*', ''):gsub('%s*$', '')					-- trim all whitespace except leading newline character '\n'
		tag = 'div'																-- must be <div> because <span> may not contain <ul>, <dd>, <dl>, <ol> tags (added later by MediaWiki)
	else
		text = mw.text.trim(text)												-- plain text
		tag = 'span'															-- so <span> is fine
	end

	return text, tag
end


--[[ -------------------------- < V A L I D A T E _ P R O T O > --------------------------

Validates value assigned to |proto=; permitted values are yes and no; yes returns as true, no returns as false,
empty string (or parameter omitted) returns as nil; any other value returns as nil with a second return value of
true indicating that some other value has been assigned to |proto=.

]]

local function validate_proto(proto_param)
	if proto_param == 'yes' then
		return true
	elseif proto_param == 'no' then
		return false
	elseif is_set(proto_param) then
		return nil, true														-- |proto= something other than 'yes' or 'no'
	else
		return nil																-- missing or empty
	end
end


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

Common function to return language name from the data set according to IETF tag.

Returns language name.

]]

local function language_name_get(ietf, code, cat)
	ietf = ietf:lower()															-- ietf:lower() because format_ietf_tag() returns mixed case
	if override_table[ietf] then												-- look for whole IETF tag in override table
		return override_table[ietf][1]	
	elseif override_table[code] then											-- not there so try basic language code
		return override_table[code][1]
	elseif lang_table[code] then												-- shift to IANA code/name table
		return lang_table[code][1]												-- table entries sometimes have multiple names, always take the first one
	elseif lang_dep_table[code] then
		if cat then
			table.insert(maintenance_categories, string.format(tracking_categories["CATEGORY_LANG_DEPRECATED"], code))
			table.insert(maintenance_messages, string.format(error_messages["CODE_DEPRECATED"], code))
		end
		return lang_dep_table[code][1]											-- table entries sometimes have multiple names, always take the first one
	end
end


--[[ -------------------------- < L A N G _ A N D _ L A N G _ X X _ S H A R E D _ S E T U P > --------------------------

Shared code used by both {{Lang}} and {{Lang-xx}} templates to setup the parameters.
Parameters required are the args passed to the template
and the template name being called, which is used for error messages.

Returns 6 parameters in this order:
-- args
-- script
-- code
-- language_name
-- tag
-- error_msg

If error_msg returned is not nil, it should be returned back
to the invoking function and not passed to make_error_msg()
as it was already handled.

]]

local function lang_and_lang_xx_shared_setup(args, template)
	local msg = validate_text(template, args)									-- ensure that |text= is set
	if is_set(msg) then															-- msg is an already-formatted error message
		return nil, nil, nil, nil, nil, msg
	end

	local tag
	args.text, tag = html_tag_select(args.text)									-- inspects text; returns appropriate HTML tag with text trimmed accordingly

	validate_cat_args(args)														-- determine if categorization should be suppressed

	args.rtl = args.rtl == 'yes'												-- convert to boolean: 'yes' -> true, other values -> false

	args.proto, msg = validate_proto(args.proto)								-- return boolean, or nil, or nil and error message flag
	if msg then
		return nil, nil, nil, nil, nil, make_error_msg(error_messages["INVALID_PROTO"], args, template)
	end

	local subtags = {}															-- IETF subtags script, region, variant, and private
	local code																	-- the language code
	code, subtags.script, subtags.region, subtags.variant, subtags.private, msg = get_ietf_parts(args.code, args.script, args.region, args.variant)	-- private omitted because private

	if msg then
		return nil, nil, nil, nil, nil, make_error_msg(msg, args, template)
	end

	args.italic, msg = validate_italic(args)
	if msg then
		return nil, nil, nil, nil, nil, make_error_msg(msg, args, template)
	end

	if is_set(subtags.script) then												-- if script set, override rtl setting
		if in_array(subtags.script, lang_data.rtl_scripts) then
			args.rtl = true														-- script is an rtl script
		else
			args.rtl = false													-- script is not an rtl script
		end
	end

	args.code = format_ietf_tag(code, subtags.script, subtags.region, subtags.variant, subtags.private)	-- format to recommended subtag styles
	local language_name = language_name_get(args.code, code, true)				-- get language name; try IETF tag first, then code without variant then code with variant

	args.text = proto_prefix(args.text, language_name, args.proto)				-- prefix proto-language text with an asterisk

	return args, subtags.script, code, language_name, tag, nil
end


--[[ -------------------------- < _ L A N G > --------------------------

Entry point for {{Lang}}.

There should be no reason to set parameters in the {{Lang}} {{#invoke:}}
	<includeonly>{{#invoke:lang|lang}}</includeonly>

Parameters are received from the template's frame (parent frame).

]]

local function _lang(args)
	local template = args.template or strings["TEMPLATE_LANG"]

	if args[1] and args.code then
		return make_error_msg(string.format(error_messages["CONFLICTING_POSITIONAL_AND_NAMED"], "1", "code"), args, template)
	else
		args.code = args[1] or args.code										-- prefer args.code
	end

	if args[2] and args.text then
		return make_error_msg(string.format(error_messages["CONFLICTING_POSITIONAL_AND_NAMED"], "2", "text"), args, template)
	else
		args.text = args[2] or args.text										-- prefer args.text
	end

	-- |script=, |region=, |variant= not supported because they should be part of args.code ({{{1}}} in {{Lang}}); copied from previous comment.
	args.script = nil
	args.region = nil
	args.variant = nil

	local script 																-- IETF script
	local code																	-- the language code
	local language_name
	local tag																	-- HTML tag
	local error_msg
	args, script, code, language_name, tag, error_msg = lang_and_lang_xx_shared_setup(args, template)

	if error_msg then
		return error_msg
	end

	if args.italic == nil then													-- nil when |italic= absent or not set or |italic=default; args.italic controls
		if (script == 'latn') or								 				-- script is latn
			(mw.language.getContentLanguage().code ~= code
				and not is_set(script)
				and not has_poem_tag(args.text)
				and unicode.is_Latin(args.text)
				) then															-- text not this wiki's language, no script specified and not in <poem> markup but is wholly latn script (auto-italics)
				args.italic = 'italic'											-- DEFAULT for {{Lang}} templates is upright; but if latn script set for font-style: italic
		else
			args.italic = 'inherit'												-- italic not set and script not latn; inherit current style
		end
	end

	if args.italic == 'invert' and tag == 'span' then							-- invert only supported for in-line content
		args.text = invert_italics(args.text)
	end

	args.text = proto_prefix(args.text, language_name, args.proto)				-- prefix proto-language text with an asterisk

	local out = {}
	table.insert(out, make_text_html(args.code, args.text, tag, args.rtl, args.italic, args.size, language_name))
	table.insert(out, make_category(code, language_name, args.nocat))
	table.insert(out, render_maintenance(args.nocat))							-- maintenance messages and categories

	return table.concat(out)													-- put it all together and done
end


--[[ -------------------------- < L A N G > --------------------------

Entry point for {{Lang}}.

There should be no reason to set parameters in the {{Lang}} {{#invoke:}}
	<includeonly>{{#invoke:lang|lang}}</includeonly>

Parameters are received from the template's frame (parent frame).

]]

local function lang(frame)
	local args = getArgs(frame, {												-- this code so that we can detect and handle wiki list markup in text
		valueFunc = function(key, value)
			if key == 2 or key == 'text' then									-- the 'text' parameter; do not trim white space
				return value													-- return untrimmed 'text'
			elseif value then													-- all other values: if the value is not nil
				value = mw.text.trim(value)										-- trim whitespace
				if value ~= '' then												-- empty string when value was only whitespace
					return value
				end
			end
			return nil															-- value was empty or contained only whitespace
		end																		-- end of valueFunc
		})

	return _lang(args)
end


--[[ -------------------------- < L A N G _ X X > --------------------------

For the {{L-xx}} templates, the only parameter required to be set in the template is the language code. All
other parameters can, usually should, be written in the template call. For {{Lang-xx}} templates for languages
that can have multiple writing systems, it may be appropriate to set |script= as well.

For each {{Lang-xx}} template choose the appropriate entry-point function so that this function knows the default
styling that should be applied to text.

For normal, upright style:
	<includeonly>{{#invoke:lang|lang_xx_inherit|code=xx}}</includeonly>
For italic style:
	<includeonly>{{#invoke:lang|lang_xx_italic|code=xx}}</includeonly>

All other parameters should be received from the template's frame (parent frame)

Supported parameters are:
	|code = (required) the IANA language code
	|script = IANA script code; especially for use with languages that use multiple writing systems
	|region = IANA region code
	|variant = IANA variant code
	|text = (required) the displayed text in language specified by code
	|link = boolean false ('no') does not link code-specified language name to associated language article
	|rtl = boolean true ('yes') identifies the language specified by code as a right-to-left language
	|nocat = boolean true ('yes') inhibits normal categorization; error categories are not affected
	|cat = boolian false ('no') opposite form of |nocat=
	|italic = boolean true ('yes') renders displayed text in italic font; boolean false ('no') renders displayed text in normal font; not set renders according to args.initial_style_state
	|lit = text that is a literal translation of text
	|label = 'none' to suppress all labeling (language name, 'translit.', 'lit.')
				any other text replaces language-name label - automatic wikilinking disabled
	
	for those {{Lang-xx}} templates that support transliteration (those templates where |text= is not entirely latn script):
	|translit = text that is a transliteration of text
	|translit-std = the standard that applies to the transliteration
	|translit-script = ISO 15924 script name; falls back to code

For {{Lang-xx}}, the positional parameters are:
	{{{1}}}	text
	{{{2}}}	transliterated text
	{{{3}}}	literal translation text
	
No other positional parameters are allowed.

]]

local function _lang_xx(args)
	local template = args.template or strings["TEMPLATE_LANG_XX"]

	if args[1] and args.text then
		return make_error_msg(string.format(error_messages["CONFLICTING_POSITIONAL_AND_NAMED"], "1", "text"), args, template)
	else
		args.text = args[1] or args.text										-- prefer args.text
	end

	if args[2] and args.translit then
		return make_error_msg(string.format(error_messages["CONFLICTING_POSITIONAL_AND_NAMED"], "2", "translit"), args, template)
	else
		args.translit = args[2] or args.translit								-- prefer args.translit
	end

	if args[3] and (args.translation or args.lit) then
		return make_error_msg(error_messages["CONFLICTING_LIT_TRANSLATION"], args, template)
	elseif args.translation and args.lit then
		return make_error_msg(string.format(error_messages["CONFLICTING_NAMED_AND_NAMED"], "lit", "translation"), args, template)
	else
		args.translation = args[3] or args.translation or args.lit				-- prefer args.translation
	end

	if args.links and args.link then
		return make_error_msg(string.format(error_messages["CONFLICTING_NAMED_AND_NAMED"], "links", "link"), args, template)
	else
		args.link = args.link or args.links										-- prefer args.link
	end

	local script																-- IETF script
	local code																	-- the language code
	local language_name
	local tag																	-- HTML tag
	local error_msg
	args, script, code, language_name, tag, error_msg = lang_and_lang_xx_shared_setup(args, template)
	
	if error_msg then
		return error_msg
	end

	if args.italic == nil then													-- args.italic controls
		if is_set(script) then
			if script == 'latn' then
				args.italic = 'italic'											-- |script=Latn; set for font-style: italic
			else
				args.italic = args["initial_style_state"]						-- italic not set; script is not latn; set for font-style: <initial_style_state>
			end
		else
			args.italic = args["initial_style_state"]							-- here when |italic= and |script= not set; set for font-style: <initial_style_state>
		end
	end

	if args.italic == 'invert' then
		args.text = invert_italics(args.text)
	end

	local category_name = language_name											-- category names retain IANA parenthetical disambiguators (if any)
	language_name = language_name:gsub('%s+%b()', '')							-- remove IANA parenthetical disambiguators or qualifiers from names that have them

	args.text = proto_prefix(args.text, language_name, args.proto)				-- prefix proto-language text with an asterisk

	local out = {}
	local label
	if args.label then
		if args.label ~= 'none' then
			label = args.label													-- custom label
		end
	else
		if args.link == 'no' then
			label = language_name												-- language name without wikilink
		else
			if language_name:find('languages') then
				label = make_wikilink(language_name)							-- collective language name uses simple wikilink
			elseif lang_data.article_name[code] then
				label = make_wikilink(lang_data.article_name[code][1], language_name)	-- language name with wikilink from override data
			else
				label = make_wikilink(language_name .. ' language', language_name)	-- language name with wikilink
			end
		end
	end

	table.insert(out, string.format(strings["LABEL_LANGUAGE"], label, make_text_html(args.code, args.text, tag, args.rtl, args.italic, args.size, nil)))

	if is_set(args.translit) and not unicode.is_Latin(args.text) then			-- transliteration (not supported in {{Lang}}); not supported when args.text is wholly latn text (this is an imperfect test)
		local translit_label
		if args.label ~= 'none' then

			local translit_script_name											-- name associated with IANA (ISO 15924) script code
			if script_table[args['translit-script']] then						-- when |translit-script= is set, try to use the script's name
				translit_script_name = script_table[args['translit-script']][1]
			else
				translit_script_name = language_name							-- fall back on language name
			end

			local translit_title = mw.title.makeTitle(0, string.format(strings["ROMANIZATION_OF"], translit_script_name))	-- make a title object
			if translit_title.exists and (args.link ~= 'no') then
				translit_label = make_wikilink(string.format(strings["ROMANIZATION_OF"], translit_script_name or language_name), strings["ROMANIZED"])	-- make a wikilink if there is an article to link to
			else
				translit_label = strings["ROMANIZED"]							-- else plain text
			end
		end

		local translit = make_translit(args.code, language_name, args.translit, args['translit-std'], args['translit-script'])
		if is_set(translit) then
			table.insert(out, string.format(strings["LABEL_TRANSLIT"], translit_label, translit))
		else
			return make_error_msg(string.format(error_messages["INVALID_TRANSLIT_STD_VALUE"], args['translit-std']), args, template)
		end
	end

	if is_set(args.translation) then											-- translation (not supported in {{Lang}})
		local translation_label
		if args.label ~= 'none' then
			if args.link == 'no' then
				translation_label = strings["LITERAL_TRANSLATION_ABBR"]
			else
				translation_label = make_wikilink(strings["LITERAL_TRANSLATION_TEXT"], strings["LIT"])
			end
		end
		table.insert(out, string.format(strings["LABEL_TRANSLATION"], translation_label, args.translation))
	end
	
	table.insert(out, make_category(code, category_name, args.nocat))
	table.insert(out, render_maintenance(args.nocat))							-- maintenance messages and categories

	return table.concat(out)													-- put it all together and done
end


--[[ -------------------------- < L A N G _ X X _ A R G S _ G E T > --------------------------

Common function to get args table from {{Lang-??}} templates.

Returns table of args.

]]

local function lang_xx_args_get(frame)
	local args = getArgs(frame,	{
		parentFirst = true,														-- parameters in the template override parameters set in the {{#invoke:}}
		valueFunc = function(key, value)
			if key == 1 then													-- the 'text' parameter; do not trim white space
				return value													-- return untrimmed 'text'
			elseif value then													-- all other values: if the value is not nil
				value = mw.text.trim(value)										-- trim whitespace
				if value ~= '' then												-- empty string when value was only whitespace
					return value
				end
			end
			return nil															-- value was empty or contained only whitespace
		end																		-- end of valueFunc
	})

	return args
end


--[[ -------------------------- < L A N G _ X X _ I T A L I C > --------------------------

Entry point for those {{Lang-xx}} templates that call lang_xx_italic().
Sets the initial style state to italic.

]]

local function lang_xx_italic(frame)
	local args = lang_xx_args_get(frame)
	
	args["initial_style_state"] = 'italic'
	return _lang_xx(args)
end


--[[ -------------------------- < _ L A N G _ X X _ I T A L I C > --------------------------

Entry point ffrom another module.
Sets the initial style state to italic.

]]

local function _lang_xx_italic(args)
	args["initial_style_state"] = 'italic'
	return _lang_xx(args)
end


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

Entry point for those {{Lang-xx}} templates that call lang_xx_inherit().
Sets the initial style state to inherit.

]]

local function lang_xx_inherit(frame)
	local args = lang_xx_args_get(frame)

	args["initial_style_state"] = 'inherit'
	return _lang_xx(args)
end


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

Entry point from another module.
Sets the initial style state to inherit.

]]

local function _lang_xx_inherit(args)
	args["initial_style_state"] = 'inherit'
	return _lang_xx(args)
end


--[[ -------------------------- < _ I S _ I E T F _ T A G > --------------------------

Returns true when a language name associated with IETF language tag exists; nil else.
IETF language tag must be valid.

All code combinations supported by {{Lang}} and the {{Lang-xx}} templates are supported by this function.

Module entry point from another module.

]]

local function _is_ietf_tag(tag)												-- entry point when this module is require()d into another
	local c, s, r, v, p, err													-- code, script, region, variant, private, error message
	c, s, r, v, p, err = get_ietf_parts(tag)									-- disassemble tag into constituent part and validate

	return ((c and not err) and true) or nil									-- return true when code portion has a value without error message; nil else
end


--[[ -------------------------- < I S _ I E T F _ T A G > --------------------------

Module entry point from an {{#invoke:}}.

]]

local function is_ietf_tag(frame)
	return _is_ietf_tag(getArgs(frame)[1])										-- args[1] is the IETF language tag to be tested; getArgs() so we also get parent frame
end


--[[ -------------------------- < _ N A M E _ F R O M _ T A G > --------------------------

Returns language name associated with IETF language tag if valid; error message else.

All code combinations supported by {{Lang}} and the {{Lang-xx}} templates are supported by this function.

Set invoke's |link= parameter to yes to get wikilinked version of the language name.

Module entry point from another module.

]]

local function _name_from_tag(args)
	local raw_code = args[1]													-- save a copy of the input IETF subtag

	local subtags = {}															-- IETF subtags script, region, variant, and private
	local code																	-- the language code
	local msg																	-- gets an error message if IETF language tag is malformed or invalid
	code, subtags.script, subtags.region, subtags.variant, subtags.private, msg = get_ietf_parts(raw_code)

	validate_cat_args(args)
	if msg then
		if not args.nocat and args["from_invoke"] then							-- if called from an invoke and not manually set nocat to off, allow categorization
			args.nocat = nil
		end
		return make_error_msg(msg, args, args['template'])
	end

	raw_code = format_ietf_tag(code, subtags.script, subtags.region, subtags.variant, subtags.private)	-- format to recommended subtag styles; private omitted because private
	local language_name = language_name_get(raw_code, code)						-- get language name; try IETF tag first, then code without variant then code with variant
	language_name = language_name:gsub('%s+%b()', '')							-- remove IANA parenthetical disambiguators or qualifiers from names that have them

	local link = 'yes' == args['link']											-- make a boolean
	local label = args.label
	if link then																-- when |link=yes, wikilink the language name
		if language_name:find('languages') then
			language_name = make_wikilink(language_name, label)					-- collective language name uses simple wikilink
		elseif lang_data.article_name[code] then
			language_name = make_wikilink(lang_data.article_name[code][1], label or language_name)	-- language name with wikilink from override data
		else
			language_name = make_wikilink(language_name .. ' language', label or language_name)	-- language name with wikilink
		end
	end

	return language_name
end


--[[ -------------------------- < N A M E _ F R O M _ T A G > --------------------------

Module entry point from an {{#invoke:}}.

]]

local function name_from_tag(frame)												-- entry point from an {{#invoke:Lang|name_from_tag|<IETF tag>|link=<yes>|template=<template name>}}
	local args = getArgs(frame)													-- getArgs() so we also get parent frame
	args["from_invoke"] = true
	return _name_from_tag(args)													-- pass-on the args table
end


--[[ -------------------------- < _ T A G _ F R O M _ N A M E > --------------------------

Returns the IETF language tag associated with the language name.
Spelling of language name must be correct according to the spelling in the source tables.
When a standard language name has a parenthetical disambiguator,
that disambiguator must be omitted (they are not present in the data name-to-tag tables).

Module entry point from another module.

]]

local function _tag_from_name(args)
	local msg

	if args[1] and args[1] ~= '' then
		local data = mw.loadData('Module:Lang/tag from name')					-- get the reversed data tables
		local lang = args[1]:lower()											-- allow any-case for the language name (spelling must till be correct)
		local tag = data.rev_override_table[lang] or data.rev_lang_table[lang] or data.rev_lang_dep_table[lang]	-- get the code; look first in the override then in the standard

		if tag then
			return tag, true													-- language name found so return tag and done; second return used by is_lang_name()
		else
			msg = string.format(error_messages["LANGUAGE_NOT_FOUND"], args[1])	-- language name not found, error message
		end
	else
		msg = error_messages["LANGUAGE_NOT_PROVIDED"]							-- language name not provided, error message
	end

	validate_cat_args(args)
	if msg then
		if not args.nocat and args["from_invoke"] then							-- if called from an invoke and not manually set nocat to off, allow categorization
			args.nocat = nil
		end
		return make_error_msg(msg, args, args['template'])
	end
end


--[[ -------------------------- < T A G _ F R O M _ N A M E > --------------------------

Module entry point from an {{#invoke:}}.

]]

local function tag_from_name(frame)												-- entry point from an {{#invoke:Lang|tag_from_name|<language name>|link=<yes>|template=<template name>}}
	local args = getArgs(frame)													-- getArgs() so we also get parent frame
	args["from_invoke"] = true
	local result, _ = _tag_from_name(args)										-- pass-on the args table and suppress second return used by is_lang_name()
	return result		
end


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

Module entry point from an {{#invoke:}}.

]]

local function is_lang_name(frame)
	local _, result = _tag_from_name(getArgs(frame))							-- pass-on the args table, nothing else; getArgs() so we also get parent frame; suppress second return used by tag_from_name()
	return result and true or nil		
end


--[[ -------------------------- < _ T R A N S L > --------------------------

Module entry point from another module.

]]

local function _transl(args)
	local template = strings["TEMPLATE_TRANSL"]
	local title_table = lang_data.translit_title_table							-- table of transliteration standards and the language codes and scripts that apply to those standards

	if is_set(args[3]) then														-- [3] set when {{Transl|code|standard|text}}
		args.text = args[3]														-- get the transliterated text
		args.translit_std = args[2] and args[2]:lower()							-- get the standard; lower case for table indexing

		if not title_table[args.translit_std] then
			return make_error_msg(string.format(error_messages["UNRECOGNIZED_TRANSLITERATION_STANDARD"], args.translit_std), args, template)
		end
	else
		if is_set(args[2]) then													-- [2] set when {{Transl|code|text}}
			args.text = args[2]													-- get the transliterated text
		else
			if args[1] and args[1]:match('^%a%a%a?%a?$') then					-- args[2] missing; is args[1] a code or its it the transliterated text?
				return make_error_msg(error_messages["NO_TEXT"], args, template)-- args[1] is a code so we're missing text
			else
				args.text = args[1]												-- args[1] is not a code so we're missing that; assign args.text for error message
				return make_error_msg(string.format(error_messages["MISSING_LANGUAGE_OR_SCRIPT_CODE"]), args, template)
			end
		end
	end

	if is_set(args[1]) then														-- IANA language code used for HTML lang= attribute; or ISO 15924 script code
		if args[1]:match('^%a%a%a?%a?$') then									-- args[1] has correct form?
			args.code = args[1]:lower()											-- use the language/script code; only (2, 3, or 4 alpha characters); lower case because table indexes are lower case
		else
			return make_error_msg(string.format(error_messages["UNRECOGNIZED_LANGUAGE_OR_SCRIPT_CODE"], args[1]), args, template)	-- invalid language / script code
		end
	else
		return make_error_msg(string.format(error_messages["MISSING_LANGUAGE_OR_SCRIPT_CODE"]), args, template)	-- missing language / script code so quit
	end

	local msg
	args.italic, msg = validate_italic(args)
	if msg then
		return make_error_msg(msg, args, template)
	end

	if args.italic == 'italic' then												-- 'italic' when |italic=yes; because that is same as absent or not set and |italic=default
		args.italic = nil														-- set to nil; 
	end

	local language_name															-- language name that matches language code; used for tool tip
	local script																-- IANA script
	if override_table[args.code] then											-- is code a language code defined in the override table?
		language_name = override_table[args.code][1]
	elseif lang_table[args.code] then											-- is code a language code defined in the standard language code tables?
		language_name = lang_table[args.code][1]
	elseif lang_dep_table[args.code] then										-- is code a language code defined in the deprecated language code tables?
		language_name = lang_dep_table[args.code][1]
	elseif script_table[args.code] then											-- if here, code is not a language code; is it a script code?
		language_name = script_table[args.code][1]
		script = args.code														-- code was an ISO 15924 script so use that instead
		args.code = ''															-- unset because not a language code
	else
		return make_error_msg(string.format(error_messages["UNRECOGNIZED_LANGUAGE_OR_SCRIPT_CODE"], args.code), args, template)	-- invalid language / script code
	end
																				-- here only when all parameters passed to make_translit() are valid
	return make_translit(args.code, language_name, args.text, args.translit_std, script, args.italic)
end


--[[ -------------------------- < T R A N S L > --------------------------

Module entry point from an {{#invoke:}}.

]]

local function transl(frame)
	return _transl(getArgs(frame))
end


--[[ -------------------------- < C A T E G O R Y _ F R O M _ T A G > --------------------------

Returns category name associated with IETF language tag if valid; error message else.

All code combinations supported by {{Lang}} and the {{Lang-xx}} templates are supported by this function.

Module entry point from another module.

]]

local function _category_from_tag(args)
	local raw_code = args[1]													-- save a copy of the input IETF subtag

	local subtags = {}															-- IETF subtags script, region, variant, and private
	local code																	-- the language code
	local msg																	-- gets an error message if IETF language tag is malformed or invalid
	code, subtags.script, subtags.region, subtags.variant, subtags.private, msg = get_ietf_parts(raw_code)

	validate_cat_args(args)
	if msg then
		if not args.nocat and args["from_invoke"] then							-- if called from an invoke and not manually set nocat to off, allow categorization
			args.nocat = nil
		end
		return make_error_msg(msg, args, args['template'])
	end

	raw_code = format_ietf_tag(code, subtags.script, subtags.region, subtags.variant, subtags.private)	-- format to recommended subtag styles; private omitted because private
	local category_name = language_name_get(raw_code, code)						-- get language name; try IETF tag first, then code without variant then code with variant
	category_name = make_category(code, category_name, nil, true):gsub('[%[%]]', '')
	
	if args.link then
		return string.format("[[:%s]]", category_name)
	else
		return category_name
	end
end


--[[ -------------------------- < C A T E G O R Y _ F R O M _ T A G > --------------------------

Module entry point from an {{#invoke:}}.

]]

local function category_from_tag(frame)											-- entry point from an {{#invoke:Lang|category_from_tag|<IETF tag>|template=<template name>}}
	local args = getArgs(frame)													-- getArgs() so we also get parent frame
	args["from_invoke"] = true
	return _category_from_tag(args)												-- pass-on the args table, nothing else
end


--[[ -------------------------- < E X P O R T E D _ F U N C T I O N S > --------------------------
]]

return {
	category_from_tag = category_from_tag,
	lang = lang,																-- entry point for {{Lang}}
	lang_xx_inherit = lang_xx_inherit,											-- entry points for {{Lang-??}}
	lang_xx_italic = lang_xx_italic,
	is_ietf_tag = is_ietf_tag,
	is_lang_name = is_lang_name,
	tag_from_name = tag_from_name,												-- returns IETF tag associated with language name
	name_from_tag = name_from_tag,												-- used for template documentation; possible use in ISO 639 name from code templates
	transl = transl,															-- entry point for {{Transl}}
	
	_category_from_tag = _category_from_tag,									-- entry points when this module is require()d into other modules
	_lang = _lang,
	_lang_xx_inherit = _lang_xx_inherit,
	_lang_xx_italic = _lang_xx_italic,
	_is_ietf_tag = _is_ietf_tag,
	get_ietf_parts = get_ietf_parts,
	_tag_from_name = _tag_from_name, 
	_name_from_tag = _name_from_tag,
	_transl = _transl,
}