Re: [nmh-workers] Flagging messages

[Ken Hornstein]

Geez Valdis, I think we've talked about this before on this very list!

>So the grammar was changed to explicitly specify where spaces,
>and where comments, could be inserted (in the middle of a time
>is not one of them).   I don't recall whether before the ":"
>after a field-name is one of them however (I tend to assume not,
>and I should check, but...).

Comments and white space, sadly, are still allowed in all sorts of
crazy places using the "Obsolete" syntax as of RFC 5322.  From §4:

   One important difference between the obsolete (interpreting) and the
   current (generating) syntax is that in structured header field bodies
   (i.e., between the colon and the CRLF of any structured header
   field), white space characters, including folding white space, and
   comments could be freely inserted between any syntactic tokens.  This
   allowed many complex forms that have proven difficult for some
   implementations to parse.

Also, from §4.2:

   In the obsolete syntax, any amount of folding white space MAY be
   inserted where the obs-FWS rule is allowed.  This creates the
   possibility of having two consecutive "folds" in a line, and
   therefore the possibility that a line which makes up a folded header
   field could be composed entirely of white space.

Good times!

--Ken