Re: #1132: Allowing IP addresses as path-identiites - Poll result

[Frank Ellermann <nobody@xxxxxxxxxxxxxxxxx>]

Charles Lindsey wrote:

> Every <label> has to begin with ALPHA

That's unfortunately not more the case for the ldh-rule,
it's only the toplabel (compare RfC 2396 and others).

If you and Harald want to "allow" underscore you cannot
exclude "non-toplabel starting with DIGIT" at the same
time, that would be inconsistent.

>> say tail-entry = path-identity
> No

ACK, here I dropped the "starts with DIGIT" ball.

 [about no bareword> in <source-identity>]
> No, you still need <bareword> as a possibility for
> <source-identity>, because the article may have arrived
> by UUCP, or it may have arrived from an uninteresting IP
> address leased to a dialup, and what you want to quote
> is the "true source of the article" which you only knew
> because the sending site authenticted itself with SASL,
> using some <bareword> as its identity.

Sigh...  okay, IIRC Harald's proposal also covered that
idea, so "diag" or "source" can be an IP or just anything
also allowed as <path-identity>.

> I think we have to accept that this grammar is always going
> to be ambiguous (but mostly it doesn't matter). Harald's
> grammar is even more ambiguous.

Your second version (pseudo-TLD ".MISMATCH") had that clear.
It's possible to preserve this idea for "!MISMATCH" if we
restrict "diag" to "diag!MISMATCH".

Otherwise it's hard to see the point of "diag":  If nobody
but the site adding it knows what it is it's that red and
green sparkled duck feeding itself with dead:beef...

...at least we asked it to stay out of Injection-Info and
Xref, is that really all, syntactically ?

> my syntax severely limited where [FWS] was allowed
> (essentially between things added by one site). If you
> want to relax that, then I shall have to take care it
> does not arise inside a "!!".

I've no problem with "!" [FWS] "!" if that allows for a
syntax where we get this concept:

- either an (old) site doesn't care, then it shouldn't
  mess with "POSTED" / MISMATCH / "!!" / "diag" / "source"

- or it cares, then the two main cases (excl. POSTED) are
  "diag!MISMATCH!" or "!" (= match).

I consider the left of two adjacent "!" as shorthand for
"source!MATCH!" in a Path: site!source!MATCH!source!...

Not because I like potential cases of "!" FWS "!", but
as concept _IFF_ we want to restrict "diag" to "MISMATCH":

 path-diag = [ path-sep "POSTED" ]
             [ ( path-sep ( IP-address / path-identity )
                  path-sep "MISMATCH" ) / ( [FWS] "!" ) ]
                                          ^^^^^^^^^^^^^

The part ( [FWS] "!" ) is that match-shorthand.  For a
syntax with those read and green sparkled ducks it's of
course a bad idea to allow [FWS] "within" the "!!" case.

At least Harald's version allowed ...!!MISMATCH... or
...MISMATCH!!...  I hoped to remove this oddity somehow.

                    Bye, Frank