# File lib/rubigen/commands.rb, line 657
      def complex_template(relative_source, relative_destination, template_options = {})

         begin
           dest_file = destination_path(relative_destination)
           source_to_update = File.readlines(dest_file).join
         rescue Errno::ENOENT
           logger.missing relative_destination
           return
         end

         logger.refreshing "#{template_options[:insert].gsub(/\.erb/,'')} inside #{relative_destination}"

         begin_mark = Regexp.quote(template_part_mark(template_options[:begin_mark], template_options[:mark_id]))
         end_mark = Regexp.quote(template_part_mark(template_options[:end_mark], template_options[:mark_id]))

         # Refreshing inner part of the template with freshly rendered part.
         rendered_part = render_template_part(template_options)
         source_to_update.gsub!(/#{begin_mark}.*?#{end_mark}/m, rendered_part)

         File.open(dest_file, 'w') { |file| file.write(source_to_update) }
      end