ietf-822
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Re: Mailing List Last Call for 2822 update internet-draft

2007-07-30 01:59:33

In message <20070730073355(_dot_)GL2903(_at_)apb-laptoy(_dot_)apb(_dot_)alt(_dot_)za>, Alan Barrett <apb(_at_)cequrux(_dot_)com> writes

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.

No, but quote marks are in the list of specials, "+" and "-" are quoted-strings.

 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.

Disagree, a quoted-string is a token

RFC822 3.1.4:

  These symbols are:

                    -  individual special characters
                    -  quoted-strings
                    -  domain-literals
                    -  comments
                    -  atoms


So the "+", "-" and 4DIGIT are distinct tokens in RFC822, two quoted strings and an atom.


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.


Agreed, because a quoted-string is a single token.


Regards

--
Paul Overell         Internet Platform Development Manager, Thus plc