Module:Template translation

Documentation for this module may be created at Module:Template translation/doc

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'
    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