Template:Fallback

Template documentation
This template was imported from commons:Template:Fallback without the here unusable documentation.
Use localised subpage for the user language with fallback to {{CONTENTLANGUAGE}}
Template parameters[Edit template data]
Parameter		Description	Type	Status
page	`1`	Template name	Page name	required
lang	`2`	override user language on localised page Default {{int:Lang}}	String	optional
local p = {}
local langlist = {
 af         = {'nl'}, 
 als        = {'de'}, 
 arz        = {'ar'}, 
 bar        = {'de'}, 
 bexold     = {'betarask'}, 
 br         = {'fr'}, 
 ckb        = {'fa'}, 
 co         = {'fr'}, 
 crhcyrl    = {'crh'}, 
 crhlatn    = {'crh'}, 
 csb        = {'pl'}, 
 deat       = {'de'}, 
 dech       = {'de'}, 
 deformal   = {'de'}, 
 engb       = {'en'}, 
 frp        = {'fr'}, 
 frr        = {'de'}, 
 fy         = {'nl'}, 
 glk        = {'fa'}, 
 hifdeva    = {'hif'}, 
 hilatn     = {'hif'}, 
 ht         = {'fr'}, 
 ikecans    = {'ik'}, 
 kkarab     = {'kk'}, 
 kkcn       = {'kk'}, 
 kkcyrl     = {'kk'}, 
 kkkz       = {'kk'}, 
 kklatn     = {'kk'}, 
 kktr       = {'kk'}, 
 ksh        = {'de'}, 
 kuarab     = {'ku'}, 
 kulatn     = {'ku'}, 
 li         = {'nl'}, 
 mg         = {'fr'}, 
 mzn        = {'fa'}, 
 nds        = {'ndsnl', 'de'}, 
 ndsnl      = {'nds', 'nl'}, 
 nlinformal = {'nl'}, 
 pdt        = {'nds', 'de'}, 
 ptbr       = {'pt'}, 
 ruggrek    = {'ruq'}, 
 rulatn     = {'ruq'}, 
 ruqcyrl    = {'ruq'}, 
 srec       = {'sr'}, 
 srel       = {'sr'}, 
 szl        = {'pl'}, 
 tgcyrl     = {'tg'}, 
 tglatn     = {'tg'}, 
 ttcyrl     = {'tt'}, 
 ttlatn     = {'tt'}, 
 ty         = {'fr'}, 
 vec        = {'it'}, 
 vls        = {'nl'}, 
 wa         = {'fr'}, 
 zea        = {'nl'}, 
 zh         = {'zhhans'}, 
 zhcn       = {'zhhans'}, 
 zhhans     = {'zhcn', 'zh'}, 
 zhhant     = {'zh'}, 
 zhhk       = {'zhhant'}, 
 zhmo       = {'zhhant'}, 
 zhmy       = {'zhhans'}, 
 zhsg       = {'zhhans'}, 
 zhtw       = {'zhhant'}
}

function p.getfallback(args, lang)
	if not lang then lang = args.lang end
	
	if args[lang] then
		return 	args[lang]
	end
	if langlist[lang] then -- if there is a fallbacklist, check if there is a message for its languages 
		text = p.fallbackloop(args, langlist[lang], '')
	end
	if text then
		return text
	end
	if args.default then
		return args.default
	end
	if args.en then 
		return args.en
	end
end

function p.fallbackloop(args, totest, tested) 
	-- iterates through the langlist fallback table
	-- totest = tables of languages whose fallbacks need to be examined
	-- tested = string with language that have been examined
	for i, j in pairs(totest) do
		if args[j] and args[j] ~= '' then
				return args[j]
		end
		if langlist[j] then 
			for k, l in pairs(langlist[j]) do
				table.insert(totest, l)
			end
		end
		tested = tested .. ' ' .. j
	end
	for i, j in pairs(totest) do
		if not string.find(tested, ' ' .. j) then 
			p.getfallback(args, lang, totest, tested)
		end
	end
	return nil
end

function p.langSwitch(frame)
	args = mw.getCurrentFrame():getParent().args
	-- Return error if there is not default and no english version
	if not args.en and not args.default and args.nocat ~= '1' then
		return frame:expandTemplate{ title = "red", args = {'LangSwitch error: no default'}} .. '[[Category:LangSwitch template without default version]]' 
	end
	-- get language (either stated one or user's default language)
	if args.lang then 
		lang = args.lang
	else 
		lang = frame:preprocess( "{{int:lang}}" )
	end
	-- remove dashes from language names
	for i in pairs(args) do
		args[mw.ustring.gsub( i, "-", "")] = args[i]
	end
	-- gets the most appropriate language 
	text = p.getfallback(args)
	if text == '~' then return '' end -- ~ indicates that no message should be shown in this language
	return text 
end

return p