Rebol 程序设计/邮件列表规则

MAIL-LIST-RULES 是一个价值对象

   addr-list       none!     none
   addr            none!     none
   opt-cmt         block!    length: 5
   mailbox         block!    length: 11
   maillist        block!    length: 3
   parse-mail-list function! [data [string!]]