# File lib/buildr/core/doc.rb, line 145
      def using(*args)
        args.pop.each { |key, value| @options[key.to_sym] = value } if Hash === args.last

        until args.empty?
          new_engine = Doc.select_by_name(args.pop)
          @engine = new_engine.new(project) unless new_engine.nil?
        end

        self
      end