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 '<span class="error" style="font-size:100%">error: ' .. msg .. ' not recognized</span>' 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  }