Module:LangSwitch

-- \/  | ___   __| |_   _| | ___ _| |    __ _ _ __   __ _/ ___|_      _(_) |_ ___| |__   | |\/| |/ _ \ / _` | | | | |/ _ (_) |   / _` | '_ \ / _` \___ \ \ /\ / / | __/ __| '_ \  | |  | | (_) | (_| | |_| | |  __/_| |__| (_| | | | | (_| |___) \ 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('Module:No globals')

local p = {}

--[[ _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 = ' LangSwitch Error: no default' if args.nocat == '1' then return err else return err .. ''		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:

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 -- 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 end -- Allow input in format: -- 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) end

return p