My preference would be to stick to a completely regular syntax. I.e., always prefix the sub-segment that follows the GCS char with a "*" or a "!", but I realize that this won't be satisfactory for many others, so I think we should stick with xri 1.0 rules/syntax wrt this issue and allow any of:
xri:@foo
xri:@!foo
xri:@*foo
where xri:@foo is equivalent to xri:@*foo.
Mike
> -----Original Message-----
> From: Drummond Reed [mailto:]
> Sent: Friday, August 20, 2004 3:15 PM
> To: Lindelsee, Mike ;
> Subject: GCS chars and star in XRI authority resolution
>
>
> Per the question Mike raises: "The inclusion (or not) of the
> delimiter that
> indicates reassignability or persistence in the sub-segment that gets
> resolved is something that we'll still need to discuss as we revisit
> resolution for 1.1."
>
> I'd like to propose something I think will make both
> equivalence and XRI
> authority resolution simpler in 1.1.
>
> Per the BNF I just posted following Dave's suggestion, a GCS-rooted
> authority segment would be:
>
> GCS-authority = gcs-char [ "!" / "*" ] [ nz-segment ]
>
> Therefore a GCS char can be followed by either an nz-segment,
> or !, or *. So
> the following are all legal:
>
> @foo
> @*foo
> @!foo
>
> In XRI 1.0 we treated "@foo" and "@*foo" as equivalent. We
> said the * was
> "assumed" with any GCS char.
>
> In XRI 1.1 I'd propose that we simplify things in one of two ways:
>
> OPTION 1: BY NOT DEFINING GCS-CHAR AND GCS-CHAR* AS EQUIVALENT
>
> Instead, the rules would be that:
>
> 1) By default, the nz-segment following a GCS char is reassignable.
> 2) In XRI authority resolution, if EITHER ! or * preceed an
> nz-sub-segment,
> they are treated as part of the nz-sub-segment from the standpoint of
> resolution, i.e., are part of the value being resolved.
>
> By these rules, @foo, @*foo, and @!foo are all different
> values. "foo" is a
> reassignable sub-segment in both "@foo" and "@*foo" by definition, but
> "@foo" and "@*foo" are not equivalent.
>
> OPTION 2: BY NOT ALLOWING * DIRECTLY AFTER A GCS CHAR
>
> In ths option, the BNF would be:
>
> GCS-authority = gcs-char [ "!" ] [ nz-segment ]
>
> Again, the same two rules proposed in Option 1 would apply.
> Only now you can
> just have "@foo" and "@!foo", because "@*foo" is illegal.
>
> I believe this is actually the option most consistent with
> the rule that by
> default, the nz-sub-segment following a GCS char is
> reassignable, because it
> means that the * is already inherent in the GCS char, just
> the way it is
> inherent in a slash (reassignable sub-segment being the default after
> slash).
>
> Which do folks prefer?
>
> =Drummond
>
>
> -----Original Message-----
> From: Lindelsee, Mike [mailto:]
> Sent: Friday, August 20, 2004 2:10 PM
> To:
> Subject: RE: RE: [xri] Initial proposed XRI 1.1 ABNF and
> issues analysis
>
> Bill,
>
> I'm not clear which XRI ABNF you are asking your questions
> with respect to.
> I don't believe that the XRI below (xri:@example*:23:45)
> would be valid
> using XRI 1.0 syntax ('*' is only allowed as a GCS character
> in 1.0). The
> XRI also wouldn't be valid in the original 1.1 ABNF ('*' and ':' can't
> follow one another). It would be valid in the various
> iterations of the ABNF
> that Dave, Drummond and I have been discussing on the list --
> though the
> interpretation of the sub-segments might be slightly
> different between the
> various iterations.
>
> The latest proposal would break the XRI up as follows:
>
> 1: @
> 2: *example (reassignable sub-segment - and showing
> implicit delimiter)
> 3: *:23:45 (reassignable sub-segment)
>
> The inclusion (or not) of the delimiter that indicates
> reassignability or
> persistence in the sub-segment that gets resolved is
> something that we'll
> still need to discuss as we revisit resolution for 1.1.
>
> Mike
>
> > -----Original Message-----
> > From: Barnhill William [mailto:]
> > Sent: Friday, August 20, 2004 11:03 AM
> > To: Lindelsee, Mike
> > Cc:
> > Subject: Re: RE: [xri] Initial proposed XRI 1.1 ABNF and
> > issues analysis
> >
> >
> > Looks good to me as well, but some questions...
> > (1) Is this XRI valid? xri:@example*:23:45
> > (2) If valid, would it represent 4 resolution steps:
> > 1: @
> > 2: .example
> > 3: *:23
> > 4: *:45
> > With the '. on 1: and the '*' on 4 being implicitly stated.
> >
> > (3) If the above XRI is suppose to respresent 4 resolution
> > steps do not
> > the new rules result in only 3 steps? As :23:45 would be
> > considered one
> > segment.
> >
> > Thanks,
> >
> > Bill Barnhill
> >
>
>
>
