# File lib/rouge/lexers/lua.rb, line 31
      def builtins
        return [] unless @function_highlighting

        @builtins ||= Set.new.tap do |builtins|
          self.class.builtins.each do |mod, fns|
            next if @disabled_modules.include? mod
            builtins.merge(fns)
          end
        end
      end