Module:Template translation

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

local p = {}

function p.renderTranslatedTemplate(frame)
    --[[ 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.
        ]]
    
    local template = frame.args['template']
    local langcode = '/en'
    local namespace = 'Template:'
    
    -- Get the last subpage
    local subpage = mw.title.getCurrentTitle().subpageText
    
    --[[ 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 templateFullTitle = mw.title.new( template, 'Template' )
        if ( templateFullTitle.id == 0)
        then
            namespace=':'
        end
    
    --[[ If the subpage is a valid language code, check if a translation of the
        template exists in that language; if so, put it in langcode.
        Check first if there's an apostrophe, because they break the 
        isKnownLanguageTag function.
        ]]

    if (type (mw.ustring.match( subpage, "'" )) == nil )
    then
        if ( mw.language.isKnownLanguageTag( subpage ) )
        then
            local translation = mw.title.new( namespace..template..'/'..subpage )
            if ( translation.id ~= 0)
            then
                langcode='/'..subpage
            end
        end
    end

    -- Copy args pseudo-table to a proper table so we can feed it to expandTemplate
    local arguments = {}
    for k, v in pairs( frame.args ) do
        arguments[k] = v
    end

    -- Render the template
    return frame:expandTemplate{ title = namespace..template..langcode, args = arguments }
    
end

return p