require('Module:No globals'); local getArgs = require('Module:Arguments').getArgs  --[[--------------------------< E R R _ M S G _ M A K E >------------------------------------------------------ ]]  local function err_msg_make (msg) 	return 'ত্রুটি: ' .. msg .. ' চেনা যায়নি' end  --[[--------------------------< _ I S _ C O D E >--------------------------------------------------------------  local or require()d entry point  return true if <code> is a mediawiki recognized code; false else  <code> - language code to validate; expected to be lowercase without leading/trailing whitespace <target_lang_code> - language code for target language; expected to be valid; expected to be lowercase without leading/trailing whitespace  specifying <target_lang_code> may be a pointless exercise because of cldr fallback.  For example, 	mw.language.fetchLanguageName (crh, sq) -> Crimean Turkish because the Albanian language definitions do not have an Albanian-language version of the language name  ]]  local function _is_code (code, target_lang_code) 	code = mw.language.fetchLanguageName (code, target_lang_code); 	return  ~= code; end  --[[--------------------------< _ _ V A L I D A T E _ T A R G E T _ L A N G _ C O D E >------------------------  validates target_lang_code as a know language code; returns two values 	when target_lang_code is valid, first return value holds target_lang_code; second return value is nil 	when target_lang_code is invalid, first retrun value is nil; second return value has error message  if target_lang_code argument is nil, (missing or empty in the invoke) use local wiki's language code  ]]  local function __validate_target_lang_code (target_lang_code) 	local msg; 	 	if target_lang_code then													-- not missing or empty 		if not _is_code (target_lang_code) then									-- validate target_lang_code 			msg = err_msg_make ('target language code: ' .. target_lang_code); 			target_lang_code = nil;												-- unset as invalid 		end 	end 	if not target_lang_code then												-- if nil because missing or empty or because invlaid and we set it nil 		target_lang_code = mw.getContentLanguage():getCode();					-- use local wiki's language code 	end  	return target_lang_code, msg;												-- target_lang_code is valid or nil; msg is nil or has an error message end  --[[--------------------------< I S _ C O D E >----------------------------------------------------------------  module entry point  args[1]: language code -> <code> args[2]: optional target language code; same as <target lang code> in {{#language:<code>|<target lang code>}}; defaults to the local wiki language  return true if <code> is a mediawiki recognized code; nil else  ]]  local function is_code (frame) 	local args = getArgs (frame, { 		valueFunc = function (key, value) 			return (value and  ~= value) and value:lower():gsub ('^%s*(.-)%s*$', '%1') or nil; 		end 		}); 	local code = args[1]; 	local target_lang_code = __validate_target_lang_code (args[2]);  	return code and _is_code (code, target_lang_code) and true or nil; end  --[[--------------------------< N A M E _ F R O M _ C O D E >--------------------------------------------------  module entry point  args[1]: language code args[2]: optional target language code; same as <target lang code> in {{#language:<code>|<target lang code>}}; defaults to the local wiki language  return language-name if language-code is a mediawiki recognized code; error message string else  returned language name not guarenteed to be in target_lang_code (if specified), because mw language lists are incomplete  ]]  local function name_from_code (frame) 	local args = getArgs (frame, { 		valueFunc = function (key, value) 			return (value and  ~= value) and value:lower():gsub ('%s*(.-)%s*', '%1') or nil; 		end 		}); 	local code = args[1]; 	if not code then 		return err_msg_make ('code: (empty)'); 	end 	 	local target_lang_code, msg = __validate_target_lang_code (args[2]); 	if msg then 		return msg; 	end  	local name = mw.language.fetchLanguageName (code, target_lang_code);		-- returns empty string if code not found 	return  ~= name and name or err_msg_make ('language code: ' .. code);		-- return language name or error message end  --[[--------------------------< C O D E _ F R O M _ N A M E >--------------------------------------------------  local entry point  args[1]: language name args[2]: optional target language code; instruct this function to fetch language name list in 'this' language  return language-code if language-name is a mediawiki recognized name and target language code is valid; error message string else  second return value is a boolean used by is_name(); true when name is found; false else  ]]  local function _code_from_name (args) 	local name = args[1]; 	if not name then 		return err_msg_make ('name: (empty)'); 	end  	local target_lang_code, msg =  __validate_target_lang_code (args[2]);  	if msg then 		return msg; 	end  	local code_name_list = mw.language.fetchLanguageNames (target_lang_code, 'all');	-- get language code / name list in target_lang_code language indexed by language code 	local name_code_list = {};													-- to hold language name / code list indexed by name  	for k, v in pairs (code_name_list) do										-- spin through the code / name list and 		name_code_list[v:lower()] = k;											-- make a name / code list 	end  	if name_code_list[name] then 		return name_code_list[name], true;										-- returns code when name is found and true for is_name() 	else 		return err_msg_make ('language name: ' .. name), false;					-- return error message when name not found and false for is_name() 	end end  --[[--------------------------< C O D E _ F R O M _ N A M E >--------------------------------------------------  module entry point  args[1]: language name args[2]: optional target language code; instruct this function to fetch language name list in 'this' language  return language-code if language-name is a mediawiki recognized name and target language code is valid; error message string else  ]]  local function code_from_name (frame) 	local args = getArgs (frame, { 		valueFunc = function (key, value) 			return (value and  ~= value) and value:lower():gsub ('^%s*(.-)%s*$', '%1') or nil; 		end 		}); 	 	local result, _ = _code_from_name (args);									-- suppress true/false return used by is_name() 	return result; end  --[[--------------------------< I S _ N A M E >----------------------------------------------------------------  return true if <name> is a mediawiki recognized language name; false else  args[1]: language name args[2]: optional target language code; instructs _code_from_name to fetch language name list in 'this' language 			defaults to local wiki's language;  when this parameter not valid, language name is assumed to be not valid  ]]  local function is_name (frame) 	local args = getArgs (frame, { 		valueFunc = function (key, value) 			return (value and  ~= value) and value:lower():gsub ('%s*(.-)%s*', '%1') or nil; 		end 		}); 	 	local _, result = _code_from_name (args);									-- suppress code return used by code_from_name() 	return result and true or nil; end  --[[--------------------------< E X P O R T E D   F U N C T I O N S >------------------------------------------ ]]  return { 	code_from_name = code_from_name, 	is_code = is_code, 	is_name = is_name, 	name_from_code = name_from_code,  	_is_code = _is_code,														-- entry point from another module 	}