usefor-article-13 May 2004

4.2.4.  Comments

   Strings of characters which are treated as comments may be included
   in headers wherever the syntactic element CFWS occurs.  They consist
   of characters enclosed in parentheses.  Comments may be nested.

        NOTE: Although CFWS occurs wherever whitespace is allowed in
        almost all headers, there are exceptions where only FWS is
        permitted (hence folding but no comments). Notably, this happens
        in the case of the Message-ID-, Newsgroups-, Distribution-,
        Path- and Followup-To-headers, and within the Date-header except
        right at the end.

   Since a comment is allowed to contain FWS, folding is permitted
   within it as well as immediately preceding and immediately following
   it. Also note that, since quoted-pair is allowed in a comment, the
   parenthesis and backslash characters may appear in a comment so long
   as they appear as a quoted-pair. Semantically, the enclosing
   parentheses are not part of the content of the comment; the content
   is what is contained between the two parentheses.

   Since comments have not hitherto been permitted in news articles,
   except in a few specified places, posters and posting-agents SHOULD
   NOT insert them except in those places, namely following mailboxes in
   From and similar headers (a now deprecated convention for indicating
   the owner of that mailbox), and to indicate the name of the timezone
   in Date-headers. However, compliant software MUST accept them in all
   places where they are syntactically allowed.

--- ../usefor-article-12/Comments.out          November 2003
+++ ../usefor-article-13/Comments.out          May 2004