I often receive mail from VAX/VMS systems with From fields like
Joe Bloggs, Room 10, Tel. extn 203 <BLOGGS(_at_)SCHOOL(_dot_)EDU>
The VAX/VMS system's mailer is out of spec. The name (on VMS the equivalent
beast is called a personal name) part of an address is formally a phrase, which
is in turn a sequence of one or more words, and words are either atoms or
(Side note: They're not running PMDF on the VMS system. PMDF properly quotes
VMS personal names. If you know what mailer they are running, the proper
course of action is to get whoever wrote it to fix it. I may be able to
help you do this if I knew the mailer involved.)
However, I don't know what this has to do with the conversion of a multiple
From: lines into a single From: line. This syntax problem is not likely to
arise from such a conversion, which as far as I can tell is not something
that's syntactically hard to do. (One minor point: In doing such a conversion
you do have to be careful not to violate the RFC822 rule that specifies that
only one address can appear on the From: line if no Sender: line is present.
I suppose creating a Sender: line containing the first From: address would be
the easiest workaround if you're dead set on doing such conversions.)
The mailer on the system I use (Edinburgh University's own operating system,
own mailer, UK Grey Book, high quality) tries to reply to three "people"
Tel. extn 203 <BLOGGS(_at_)SCHOOL(_dot_)EDU>
and fails with the first two.
I didn't bother to check what JANET documents say about header line syntax in
this case -- I don't have the documents handy at the moment. However, if the
mailer on the VMS system is Grey Book compliant system such as CBS, it is not
specifically bound by RFC822 except insofar as RFC822 is used by the Grey Book
specifications, and thus is not a relevant topic here.
Incidentally, most other mailers in this situation will do roughly the same
thing, PMDF included.