    # File lib/rbot/core/filters_ui.rb, line 20
      def do_list(m, params)
        g = params[:group]
        ar = @bot.filter_names(g).map { |s| s.to_s }.sort!
        if ar.empty?
          if g
            msg = _("no filters in group %{g}") % {:g => g}
          else
            msg = _("no known filters")
          end
        else
          msg = _("known filters: ") << ar.join(", ")
        end
        m.reply msg
      end