From: stu@valinor.mythical.com (Stu Labovitz)
Newsgroups: comp.mail.uucp
Subject: Interpretation of RFC-822
Keywords: whitespace, structured headers, destination
Date: Sun, 03 Jan 93 15:52:21 CST
Distribution: world
Organization: (What? Organized??) - Mythical Computer Systems

(As a preface to the following questions, I would like to make it clear
that I am _NOT_ trying to start an interpretation-war over RFC #822
(Standard for the Format of ARPA Internet Text Messages)!)  I am having
some problems interfacing the mail software at my site with that of one of
my neighbor sites.  The problem evidences itself in a difference of
interpretation of how certain headers in a mail message may be formatted.
When examining RFC #822, I noted that the meta-syntax for header fields
is as follows:

field          =       field-name ":" [ field-body ] CRLF
field-name     =       1*<any CHAR, excluding CTLs, SPACE, and ":">
field-body     =       field-body-contents [CRLF LWSP-char field-body]
field-body-comments =  <the ASCII characters making up the field body>

RFC #822 goes on to say (in Section 3.4.2, entitled "White Space") that
"in structured field bodies, multiple linear space ASCII characters
(namely HTABs and SPACEs) are treated as single spaces and may freely
surround any symbol.  In all header fields, the only place in which at
least one LWSP-char is REQUIRED is at the beginning of continuation lines
in a folded field."

In particular, I am having problems with the To: line of the header.
This line is defined as follows (with only the relevant parts being
expanded here): 

destination    =       "To"    	       ":" 1#address
       	       /       "Resent-To"     ":" 1#address
       	       /       "cc"    	       ":" 1#address
       	       /       "Resent-cc"     ":" 1#address
       	       /       "bcc"   	       ":" 1#address
       	       /       "Resent-bcc"    ":" 1#address
address	       =       mailbox / group
mailbox	       =       addr-spec / phrase route-addr
phrase 	       =       1*word
word   	       =       atom / quoted-string
addr-spec      =       local-part "@" domain
local-part     =       word *("." word)
domain 	       =       sub-domain *("." sub-domain)
sub-domain     =       domain-ref / domain-literal
domain-literal =       "[" *(dtext / quoted-pair) "]"
domain-ref     =       atom
dtext  	       =       <any CHAR excluding "[", "]", "\", & CR, &
                       including linear-white-space>
linear-white-space =   1*([CRLF] LWSP-char)
LWSP-char      =       SPACE / HTAB

Now that we've covered what I believe are the relevant sections of the
RFC, here's the question:  Does RFC #822 provide limits (either minimum or
maximum) upon the number of SPACE characters that separate the "To:" from
the mailbox on the destination line?  Must there be at least one SPACE,
and is there any reasonable interpretation to prevent the existance of
more than one SPACE?

Many, many thanks in advance for all of your help on this issue!

   Stuart L Labovitz                    Internet:  stu@valinor.mythical.com
    (insert standard disclaimer here)       UUCP:   uunet!valinor!stu
       Duct tape is like the force.  It has a light side, a dark side,
         and it holds the universe together.      --- Carl Zwanzig
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Newsgroups: comp.mail.uucp,comp.dcom.modems