[comp.mail.misc] Bracketing in mail addresses

dhesi@bsu-cs.UUCP (06/11/87)

In article <788@mcgill-vision.UUCP> mouse@mcgill-vision.UUCP (der Mouse) 
quotes somebody who says:
>> There is no such thing as a bang address.

with:
>Gee, what's that thing on the command line after "mail"?
>
>% mail snarf\!mumble\!scream\!person

This is a good time to recapitulate.  I originally posted an article
suggesting that one ought to be able to specify precedence within
a mail address, so [a!b]@c.EDU would be different from a![b@c.EDU] and 
neither would be ambiguous.

Here is a summary of the objections that were raised to my suggestion
and my response.

Objection:  We would have to add another special character to mail
addresses and there is no point in complicating things.

Response:  Actually, we already have three pairs of characters used for
bracketing:  (), [], and <>.  Since () is taken up for comments, that
leaves [] and <>.  Either set could be used.  However, ARPAnet syntax
uses [] to hold a numeric address.  It would be kinder to ARPAnet
software to let it keep the [], although there is not reason why such
software could not be modified to recognize the meaning of [] by
testing its contents to see whether they included anything other than
digits and dots.  But <> is already used to specify precedence,
although only one level of <> is used.  All we need to do is allow the
nesting of <>.

Objection: There is no such thing as a bang address.

Response:  Should we dignify this head-in-sand attitude by responding
to it?  I don't think so.

Objection:  There is no problem with precedence because @ always has
the highest precedence, and anything to the left of that is only
interpreted by the site named after the @.

Response:  This is pure chauvinism.  A user of the ! syntax, whose
mailer does not understand @ syntax, treats all addresses as made up of
components separated by bangs.  Even programs that understand both
types of addresses may arbitrarily choose one over the other.  As far
as I can tell from the documentation, smail gives precedence to the !
over the @ when it sees both in the address field of an incoming
message.  I have encountered messages whose address fields were badly
mangled because some sites gave precedence to @ and others gave
precedence to !.

Think about it, folks.  Ken Iverson designed APL to be very regular
in its operator precedence.  With prefix notation, you ought to be
able to dispense with all bracketing symbols.  So why did he retain
[] and () anyway?
-- 
Rahul Dhesi         UUCP:  {ihnp4,seismo}!{iuvax,pur-ee}!bsu-cs!dhesi

solejni@umbio.UUCP (06/25/87)

Paul, I would be grateful for assistance with mailing mail to system
HASARA5, in Netherlands.  I have no knowledge of e-mail, so if you could
recoommend a source of published information/guidelines/tutorial, I would
be most grateful.  Thanks.