Module:LangSwitch

Lua

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This module is rated as ready for general use. It has reached a mature form and is thought to be bug-free and ready for use wherever appropriate. To reduce server load and bad output, it should be improved by sandbox testing rather than repeated trial-and-error editing.

This module is subject to page protection. It is a highly visible module in use by a very large number of pages, or is substituted very frequently. Because vandalism or mistakes would affect many pages, and even trivial editing might cause substantial load on the servers, it is protected from editing.

This Lua module is used in system messages.
Changes to it can cause immediate changes to the Wikimedia user interface.
To avoid major disruption, any changes should be tested in the module's /sandbox or /testcases subpages, or in your own module sandbox. The tested changes can be added to this page in a single edit. Please discuss changes on the talk page before implementing them.

Code for Template:LangSwitch.

Code

--[[  __ __ _ _ _ ____ _ _ _   | \/ | ___ __| |_ _| | ___ _| | __ _ _ __ __ _/ ___|_ _(_) |_ ___| |__   | |\/| |/ _ \ / _` | | | | |/ _ (_) | / _` | '_ \ / _` \___ \ \ /\ / / | __/ __| '_ \   | | | | (_) | (_| | |_| | | __/_| |__| (_| | | | | (_| |___) \ V V /| | || (__| | | |  |_| |_|\___/ \__,_|\__,_|_|\___(_)_____\__,_|_| |_|\__, |____/ \_/\_/ |_|\__\___|_| |_|  |___/   Authors and maintainers: * User:Zolo - original version in Module:Fallback * User:Jarekt  ]]  -- add optional module  -- used for debugging purposes as it detects cases of unintended global variables require('strict')  local p = {}  local function add_labels(args) -- add invisible but machine readable labels to the files, which can be used to add titles to wikidata items local createTag = require('Module:TagQS').createTag -- lazy loading of the module: only for the files that need it local qsTable = {''}  -- add text of invisible tag brodcasted by the template which allows creation of QuickStatements command used to add this info to Wikidata for lang, text in pairs( args ) do  if type(lang)=='string' and mw.language.isSupportedLanguage(lang) then -- lang has to be a valid language  table.insert( qsTable, createTag('label', 'L'..lang, '"' .. text .. '"') ) end end return table.concat( qsTable, '\n') end  --[[ _langSwitch   This function is the core part of the LangSwitch template.    Example usage from Lua: text = _langSwitch({en='text in english', pl='tekst po polsku'}, lang)   Parameters:  args - table with translations by language  lang - desired language (often user's native language)   Error Handling:  ]]  function p._langSwitch(args, lang) -- args: table of translations -- Return error if there is not default and no english version if not args.en and not args.default then local err = '<b class="error">LangSwitch Error: no default</b>' if args.nocat == '1' then return err else return err .. '[[Category:LangSwitch template without default version]]' end end  -- To improve performance try quick switch, and load fallback chain only if needed.  -- In the vast majority of cases fast switch is sufficient local val = args[lang] if val == '~' then  return '' elseif val and val ~= '' then  return val  elseif args.quick then return nil end  -- get the list of accepetable language (lang + those in lang's fallback chain) and check their content assert(lang, 'LangSwitch Error: no lang') local langList = mw.language.getFallbacksFor(lang) table.insert(langList,1,lang) table.insert(langList,math.max(#langList,2),'default') for _, language in ipairs(langList) do  val = args[language] if val == '~' then  return '' elseif val and val ~= '' then  return val  end end end  --[[ langSwitch   This function is the core part of the LangSwitch template.    Example Usage from a template: {{#invoke:fallback|langSwitch|en=text in english|pl=tekst po polsku|lang={{int:lang}} }}   Parameters:  frame.args - table with translations by language  frame.args.lang - desired language (often user's native language)   Error Handling:  ]] function p.langSwitch(frame) -- version to be used from wikitext local args = frame.args -- if no expected args provided than check parent template/module args if args.en==nil and args.default==nil and args.nocat==nil then args = mw.getCurrentFrame():getParent().args  end local lang = args.lang if not lang or not mw.language.isKnownLanguageTag(lang) then lang = frame:callParserFunction( "int", "lang" ) -- get user's chosen language  end  -- add text of invisible tag brodcasted by the template which allows creation of QuickStatements command used to add this info to Wikidata local labels = '' if args.add_labels then labels = add_labels(args) end  -- Try quick switch which checks the most likely option when fallback is not needed args.quick = true; local val = p._langSwitch(args, lang) if val then return val .. labels end  -- Allow input in format: {{LangSwitch|de=Grün|es/it/pt=Verde|fr=Vert|en=Green |lang=en}} -- with multiple languages mapping to a single value local args1 = {} for name, value in pairs( args ) do  if value ~= '' and type(name)=='string' then   for str in string.gmatch( name, "([^/]+)" ) do args1[str] = value end end end return p._langSwitch(args1, lang) .. labels end  return p