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Subject: RE: GCS chars and star in XRI authority resolution
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:drummond.reed@cordance.net] > Sent: Friday, August 20, 2004 3:15 PM > To: Lindelsee, Mike ; xri@lists.oasis-open.org > 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:mlindels@visa.com] > Sent: Friday, August 20, 2004 2:10 PM > To: xri@lists.oasis-open.org > 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:barnhill_william@bah.com] > > Sent: Friday, August 20, 2004 11:03 AM > > To: Lindelsee, Mike > > Cc: xri@lists.oasis-open.org > > 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 > > > > >
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