Module:Template translation

local this = {}

function this.getLanguageSubpage()

   -- Get the last subpage (this function isolated for debugging purpose)
   local subpage = mw.title.getCurrentTitle().subpageText
   --[[Check first if there's an apostrophe, because they break the isKnownLanguageTag
       function. This test does not work with regexps, use plain search instead (no need
       to use Unicode parser, apostrophes can only appear isolated as one byte in UTF-8).
       ]]
   if (string.find(subpage, "'", 1, true) == nil)
   then
       -- Return the subpage only if it is a valid language code.
       if (mw.language.isKnownLanguageTag(subpage))
       then
           return subpage
       end
   end
   -- Otherwise there's currently no known language subpage
   return 

end

--[[If on a translation subpage (like Foobar/de), this function renders

   a given template in the same language, if the translation is available.
   Otherwise, the template is rendered in its default language, without
   modification.
   This is aimed at replacing the current implementation of Template:TNT.
   ]]

function this.renderTranslatedTemplate(frame)

   local template = frame.args['template']

   --[[Check whether the template is actually in the Template namespace, or
       if we're transcluding a main-namespace page.
       (added for backward compatibility of Template:TNT)
       ]]
       
   local namespace = 'Template'
   if frame.args['namespace']~=nil then namespace=frame.args[4] end 
   local templateFullTitle = mw.title.new(template, namespace)
   if (templateFullTitle.id == 0)
   then -- not found in the Template namespace, assume the main namespace
       namespace = 
   end

   -- Get the last subpage and check if it matches a known language code
   local langcode = 'en' -- default language template subpage to render
   local subpage = this.getLanguageSubpage()
   if (subpage ~= )
   then
       -- Check if a translation of the template exists in that language; if so, put it in langcode
       local translation = mw.title.new(template .. '/' .. subpage, namespace)
       if (translation.id ~= 0)
       then
           langcode = subpage
       end
   end

   -- Copy args pseudo-table to a proper table so we can feed it to expandTemplate
   -- Then render the template
   local arguments = {}
   for k, v in pairs(frame.args) do
       arguments[k] = v
   end
   return frame:expandTemplate{title = namespace .. ':' .. template .. '/' .. langcode, args = arguments}

end

return this