usefor-article-11 June 2003
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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.
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#Diff to first older
--- ../usefor-article-10/Comments.out April 2003
+++ ../usefor-article-11/Comments.out June 2003
@@ -4,8 +4,6 @@
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
@@ -13,17 +11,6 @@
Path- and Followup-To-headers, and within the Date-header except
right at the end.
- A comment is normally used to provide some human readable
- informational text, except at the end of a mailbox which contains no
- phrase, as in
- fred@foo.bar.example (Fred Bloggs)
- as opposed to
- "Fred Bloggs" <fred@foo.bar.example> .
-
- The former is a deprecated, but commonly encountered, usage and
- reading agents SHOULD take special note of such comments as
- indicating the name of the person whose mailbox it is. In all other
- situations a comment is semantically interpreted as a single SP.
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
@@ -34,8 +21,9 @@
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 addresses in
- From and similar headers, and to indicate the name of the timezone in
- Date-headers. However, compliant software MUST accept them in all
+ 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.