module Mail
  grammar ContentTransferEncoding

    include RFC2822
    include RFC2045

    rule primary
      CFWS encoding CFWS ";"? CFWS
    end
    
    rule encoding
      "7bits" / "8bits" /
      "7bit" / "8bit" / "binary" / "quoted-printable" / "base64" /
      ietf_token / custom_x_token
    end
    
  end
end
