Re: Mailing List Last Call for 2822 update internet-draft

On Mon, 30 Jul 2007, Alan Barrett wrote:
> > It sure was. Comments and folding white space were allowed between 
> > any two tokens in RFC 822. And since the syntax for zone was:
> > 
> >                         ("+" / "-") 4DIGIT
> > 
> > a comment was allowed between those two. I don't know how to read 
> > 3.1.4 and 3.4.3 in RFC 822 and not come up with that interpretation.
> 
> Yes, you are correct.

Hang on...  "+" and "-" are not in the list of special characters that
RFC822 section 3.1.4 says are used to delimit tokens.  So I would say
that, given input like "+0000", the sign and the digits together make
up an "atom" per the description in section 3.1.4 and the grammar in
section 3.3.  The ( ("+" / "-") 4DIGIT ) production in the grammar in
section 5.1 is looking inside a single token, not looking at two tokens.

For another example of grammar productions that look inside a single
lexical token, consider RFC822's definitions of quoted-pair and
quoted-string.  I hope nobody argues that the "\" and the CHAR in a
quoted-pair are two tokens and that LWSP is allowed between them.

--apb (Alan Barrett)