Module:Fallback
Documentation for this module may be created at Module:Fallback/doc
local p = {}
-- functions from dependant modules
local format = string.format
local insert = table.insert
local concat = table.concat
local trim = mw.text.trim
local getFallbacksFor = mw.language.getFallbacksFor
local messageNew = mw.message.new
local titleNew = mw.title.new -- maybe costly function call
local log = mw.log
local function exists(title)
local ok, result = pcall(function()
return titleNew(title).exists -- costly property read, may throw an error
end) -- return (true, result) or (false, errorobject)
return ok and result -- in case of error, assume false
end
-- List the full fallback chain from a language to default (usually English)
local function fblist(lang)
local fbtable = getFallbacksFor(lang)
insert(fbtable, 1, lang)
--[[
Take a translation from "Mediawiki:<Message-ID>/<language-code>" namespace
or from a loaded i18 resource bundle in MediaWiki for its UI messages (also
used by the "{{Int:<Message-ID>}}" parser function), before using the
provided default value. Requires args.message = 'Message-ID', instead of
args.message = 'actual translated message'.
--]]
insert(fbtable, 'message')
insert(fbtable, 'default')
return fbtable
end
-- args: table of translations; split keys into lists of individual language codes to be assigned with the same value
-- for example: {['en/fr']='variable'} like {['en']='variable', ['fr']="variable"}. Separators are any characters that are
-- not ASCII letters, digits, or hyphens; so you can also use ['en, fr'], or ['en fr'] keys.
-- The letter case for keys is never non-significant as language codes, so convert all keys to lowercase.
-- Note: the special keys "nocat" and "default" are treated like language codes.
local function splitlangs(args)
local args2 = {}
if type(args) == 'table' then
for k, v in pairs(args) do
if type(k) == 'string' then
for c in k:gmatch('[%-0-9A-Za-z]+') do
args2[c:lower()] = v
end
end
end
end
return args2
end
--[==[
Return an error if there is not default and no English version, otherwise
return the message in the most appropriate, plus the lang code as a second value.
--]==]
local function _langSwitch(args, lang)
-- Get the table of translations
args = splitlangs(args)
if not args.en and not args.default and not args.message and not args.nocat then
return error("langSwitch error: no default")
end
-- Get language (either stated one or user's default language).
if not lang then
return '<strong class="error">langSwitch error: no lang</strong>' -- must become proper error
end
-- Get the list of acceptable language (lang + those in lang's fallback chain) and check their content.
for _, code in ipairs(fblist(lang)) do
local msg = args[code]
if msg then
-- Trim the assigned message value before testing it.
msg = trim(msg)
if msg ~= '' then
if code == 'message' then
-- If this is an UI message. See [[mw:Manual:Messages API]].
msg = messageNew(args.message):inLanguage(lang)
--[==[ If this message name does not exist, converting it to
a string would not return an actual message, but this name
within curved angle brackets U+29FC/U+29FD '⧼/⧽',
part of mathematical symbols). The UI message may also be
disabled administratively if it causes problems.
--]==]
if msg:exists() and not msg:isDisabled() then
--[==[FIXME: In which language is this message?
This may be in some fallback language and not lang.
Note that some UI messages may have placeholders like '%s'
but there's no way to replace them here by actual values.
--]==]
return tostring(msg), lang
end
elseif msg == '~' then
return nil, code
else
return msg, code
end
end
end
end
return nil
end
--[==[
Version to be used from wikitext.
--]==]
local function langSwitch(frame)
local args = splitlangs(frame.args)
-- If no expected args provided, then check parent template/module args.
if not args.en and not args.default and not args.nocat then
args = frame:getParent().args
end
local lang
if args.lang and args.lang ~= '' then
lang = args.lang
args.lang = nil
else -- Get user's chosen language.
lang = frame:preprocess('{{Int:Lang}}')
end
local str, language = _langSwitch(args, lang)
return str -- Get the first value of the langSwitch, (the text) not the second (the language).
end
local function fallbackpage(base, lang, formatting)
local fblangs = fblist(lang)
for _, lang in ipairs(fblangs) do
if exists(base .. '/' .. lang) then -- costly function call
if formatting == 'table' then
return {base .. '/' .. lang, lang} -- Returns name of the page + name of the language.
else
return base .. '/' .. lang -- Returns only the page.
end
end
end
return base
end
--[==[
Logic for [[Template:Autotranslate]].
]==]
local function autotranslate(frame)
local args = frame.args
if not args.lang or args.lang == '' then
args.lang = frame:preprocess('{{Int:Lang}}') -- Get user's chosen language.
end
-- Find base page.
local base = args.base
if not base or base == '' then
return '<strong class="error">Base page not provided for autotranslate</strong>'
end
if string.sub(base, 1, 9):lower() ~= 'template:' then -- the lettercase of the namespace is not significant
base = 'Template:' .. base -- Base provided without 'Template:' part.
end
-- Find base template language subpage.
local page = fallbackpage(base, args.lang)
if not page and base ~= args.base then
-- Try the original args.base string. This case is only needed if base is not in template namespace.
page = fallbackpage(args.base, args.lang)
end
if not page then
return format('<strong class="error">no fallback page found for autotranslate (base=[[%s]], lang=%s)</strong>', args.base, args.lang)
end
-- Repack args in a standard table.
local newargs = {}
for field, value in pairs(args) do
if field ~= 'base' then
newargs[field] = value
end
end
-- Transclude {{page |....}} with template arguments the same as the ones passed to {{autotranslate}} template.
return frame:expandTemplate{ title = page, args = newargs }
end
--[==[
Translate data stored in a module.
]==]
local function translate(page, key, lang)
if type(page) == 'string' then -- If the requested translation table is not yet loaded.
page = require('Module:' .. page)
end
local val
if page[key] then
val = page[key]
elseif page.keys and page.keys[key] then -- Key 'keys" is an index of all keys, including redirects, see [[Module:i18n/datatype]].
val = page.keys[key]
end
if val then
return _langSwitch(val, lang)
else
return '⧼' .. key .. '⧽' -- U+29FC/U+29FD, like with '{{int:key}}' where message with that key does not exist
end
end
local function translatelua(frame)
local lang = frame.args.lang
local page = require('Module:' .. trim(frame.args[1])) -- Page should only contain a simple of translations.
if not lang or trim(lang) == '' then
lang = frame:preprocess('{{Int:Lang}}')
end
if frame.args[2] then
page = page[trim(frame.args[2])]
end
return _langSwitch(page, lang)
end
-- This test does not work ('Module:Fallback/tests/fallbacks' is missing)
local function runTests()
local toFallbackTest = require('Module:Fallback/tests/fallbacks')
local result = true
log('Testing fallback chains')
for i, t in ipairs(toFallbackTest) do
local fbtbl = concat(fblist(t.initial), ', ')
local expected = concat(t.expected, ', ')
local ret = (fbtbl == expected)
log(i, ret and 'passed' or 'FAILED', t.initial, (not ret) and ('FAILED\nis >>' .. fbtbl .. '<<\nbut should be >>' .. expected .. '<<\n') or '')
result = result and ret
end
return result
end
--[==[
List all input arguments of the template that calls "{{#invoke:Fallback|showTemplateArguments}}"
]==]
local function showTemplateArguments(frame)
local str = ''
for name, value in pairs(frame:getParent().args) do
if str == '' then
str = format('%s=%s', name, value) -- argument #1
else
str = format('%s, %s=%s', str, name, value) -- the rest
end
end
return str
end
-- exports
return {
fblist = fblist,
_langSwitch = _langSwitch,
langSwitch = langSwitch,
autotranslate = autotranslate,
fallbackpage = fallbackpage,
translate = translate,
translatelua = translatelua,
showTemplateArguments = showTemplateArguments,
runTests = runTests,
exists = exists,
}