Module:LangSwitch/sandbox

Lua
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This is the module sandbox page for Module:LangSwitch (diff).
See also the companion subpage for test cases.
Code

--[[  __ __ _ _ _ ____ _ _ _   | \/ | ___ __| |_ _| | ___ _| | __ _ _ __ __ _/ ___|_ _(_) |_ ___| |__   | |\/| |/ _ \ / _` | | | | |/ _ (_) | / _` | '_ \ / _` \___ \ \ /\ / / | __/ __| '_ \   | | | | (_) | (_| | |_| | | __/_| |__| (_| | | | | (_| |___) \ V V /| | || (__| | | |  |_| |_|\___/ \__,_|\__,_|_|\___(_)_____\__,_|_| |_|\__, |____/ \_/\_/ |_|\__\___|_| |_|  |___/   Authors and maintainers: * User:Zolo - original version in Module:Fallback * User:Jarekt - perfomance improvement to avoid loading fallbacks when not needed * User:Verdy_p - performance improvements, fix for 'default=*' ]]  -- add optional module  -- used for debugging purposes as it detects cases of unintended global variables require('strict')  local p = {} local insert = table.insert local concat = table.concat local gmatch = string.gmatch local getFallbacksFor = mw.language.getFallbacksFor local getCurrentFrame = mw.getCurrentFrame local isValidCode = mw.language.isValidCode  local createTag -- lazy loading of the module: only for the files that need it  --[[ Add invisible but machine readable labels to the files, which can be used to add titles to wikidata items ]] local function add_labels(args) if not createTag then createTag = require('Module:TagQS').createTag -- lazy loading of the module: only for the files that need it end -- Add text of invisible tag brodcasted by the template which allows creation of QuickStatements command used to add this info to Wikidata local qsTable = {} for key, text in pairs(args) do  if type(key) == 'string' and key ~= 'add_labels' then for code in gmatch(key:lower(), '([%-0-9a-z]+)') do if isValidCode(code) then -- code has to be a valid language insert(qsTable, createTag('label', 'L' .. code, '"' .. text .. '"')) end end end end return concat(qsTable) 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, quick, nocat) -- args: table of translations only assert(lang, 'LangSwitch Error: no lang') -- Return error if there is not 'default' and no 'en' version if not args.default and not args.en then local err = '<b class="error">LangSwitch Error: no default</b>' if nocat 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 quick switch (not using any fallbacks) is sufficient. local value = args[lang] if value or quick then return value == '~' and '' or value end -- Get the list of acceptable languages (lang + those in lang's fallback chain) and check their content. local langList = getFallbacksFor(lang) -- table.insert(langList, 1, lang) -- not needed (already checked in the quick test above) for _, language in ipairs(langList) do if language ~= 'en' or lang:sub(1, 3) == 'en-' then value = args[language] if value then return value == '~' and '' or value end end end value = args.default and args.default or args.en return value == '~' and '' or value 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)  frame.args.quick - if non-empty, disable the lookup for fallbacks  frame.args.nocat - if non-empty, disable the tracking categorization if there's no 'default' or 'en' version  Error Handling: ]] function p.langSwitch(frame) -- version to be used from wikitext local args = frame.args -- If no expected args provided, then check parent template/module args. if not(args.lang or args.en or args.default or args.quick or args.nocat) then args = getCurrentFrame():getParent().args end local lang = args.lang if not lang or lang == '' or not isValidCode(lang) then lang = frame:callParserFunction('Int', 'Lang') -- get user's chosen language  end lang = lang:lower() -- 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 -- Fast lookup for most frequent simple cases (direct match, without composite keys or fallbacks) local value = args[lang] if value and value ~= '' then return value ~= '~' and value or '' 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. -- We need a new table as we cannot change the args table from the caller's or parent's frame. local args1, nocat, quick = {}, args.nocat and args.nocat ~= '', args.quick and args.quick ~= '' for key, value in pairs(args) do if value ~= '' and type(key) == 'string' and not(key == 'lang' or key == 'quick' or key == 'nocat') then for code in gmatch(key:lower(), '([%-0-9a-z]+)') do args1[code] = value end end end return p._langSwitch(args1, lang, quick, nocat) end  return p