module Mail
  grammar ContentTransferEncoding

    include RFC2822
    include RFC2045

    rule primary
      CFWS encoding CFWS ";"? CFWS
    end
    
    rule encoding
      ietf_token "s"? {
        def text_value
          ietf_token.text_value
        end
      } / custom_x_token
    end
    
  end
end