Module:Fallback
 | This template is used on a very large number of pages. To avoid large-scale disruption and unnecessary server load, any changes should first be tested in this template's /sandbox or /testcases subpage, or in your own user space. The tested changes can then be added in one single edit to this template. Please consider discussing any changes on the talk page before implementing them. |
This Module is used as a part of the larger mechanism to show a template content in the user's interface language or the most appropriate fallback language. It is used in
and it will be used in
It will replace Template:GetFallback and Template:GetFallback2 templates.
Dependencies
- Module:Fallbacklist catalogs fallback chains for each language.
local p = {}
local langlist = require('Module:Fallbacklist')
function p.fblist(lang) -- list the full fallback chain from a language to en
local fbtable = p.fallbackloop{ lang:lower() }
table.insert(fbtable, 'default')
table.insert(fbtable, 'en')
return fbtable
end
function _inArray(x, t)
for i, v in ipairs(t) do
if v == x then return i end
end
return -1
end
function p.fallbackloop(fbtable) --list of fallback languages in string format (more convenient than tables)
local changes = false
for i, j in ipairs(fbtable) do
local seq = langlist[j]
if seq then
for k, l in ipairs(seq) do
if _inArray(l, fbtable) == -1 then
table.insert(fbtable, l)
changes = true
end
end
end
end
if changes then
return p.fallbackloop(fbtable)
end
return fbtable
end
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 and args.nocat ~= '1' then
return '<strong class="error">LangSwitch Error: no default</strong>[[Category:LangSwitch template without default version]]'
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 accpetable language (lang + those in lang's fallback chain) and check their content
local parselist = p.fblist(lang)
for i, k in ipairs(parselist) do
if args[k] == '~' then return '' end
if args[k] and args[k] ~= '' then return args[k] end
end
end
function p.langSwitch(frame) -- version to be used from wikitext
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
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
return p._langSwitch(args, lang)
end
function p.fallbackpage(base, lang, formatting)
local languages = p.fblist(lang)
for i, lng in ipairs(languages) do
if mw.title.new(base .. '/' .. lng).exists then
if formatting == 'table' then
return {base .. '/' .. lng, lng} -- returns name of the page + name of the language
else
return base .. '/' .. lng -- returns only the page
end
end
end
end
function p.autotranslate(frame) -- logic for [[template:Autotranslate]]
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,2,9) ~= 'emplate:' then
base = 'Template:' .. base -- base provided without 'Template:' part
end
-- find base template language subpage
local page = p.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 = p.fallbackpage(args.base, args.lang)
end
if not page then
return string.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
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
function p.translatelua(frame)
local lang = frame.args.lang
local page = require('Module:' .. mw.text.trim(frame.args[1])) -- page should only contain a simple of translations
if not lang or mw.text.trim(lang) == '' then
lang = frame:preprocess( "{{int:lang}}" )
end
if frame.args[2] then
page = page[mw.text.trim(frame.args[2])]
end
return p._langSwitch(page, lang)
end
function p.runTests()
local toFallbackTest = require('Module:Fallback/tests/fallbacks')
local result = true
mw.log('Testing fallback chains')
for i, t in ipairs(toFallbackTest) do
local fbtbl = table.concat(p.fblist(t.initial), ', ')
local expected = table.concat(t.expected, ', ')
local ret = (fbtbl == expected)
mw.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
function p.showTemplateArguments(frame)
-- list all input arguments of the template that calls "{{#invoke:Fallback|showTemplateArguments}}"
local str = ''
for name, value in pairs( mw.getCurrentFrame():getParent().args ) do
if str=='' then
str = string.format('%s=%s', name, value) -- argument #1
else
str = string.format('%s, %s=%s', str, name, value) -- the rest
end
end
return str
end
return p
