# ==== Parameters
    # name<~to_s>:: Name of the cookie.
    # value<~to_s>:: Value of the cookie.
    # options<Hash>:: Additional options for the cookie (see below).
    #
    # ==== Options (options)
    # :path<String>:: The path for which this cookie applies. Defaults to "/".
    # :expires<Time>:: Cookie expiry date.
    def set_cookie(name, value, options)
      options[:path] = '/' unless options[:path]
      if expiry = options[:expires]
        options[:expires] = expiry.gmtime.strftime(Merb::Const::COOKIE_EXPIRATION_FORMAT)
      end
      # options are sorted for testing purposes
      (@_headers['Set-Cookie'] ||=[]) << "#{name}=#{value}; " +
        options.map{|k, v| "#{k}=#{v};"}.sort.join(' ')
    end