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Subject: RE: [xri] RE: GCS chars and star in XRI authority resolution
I agree with Mike about the special treatment of "!". Also, the proposal about submitting "@foo" to the @ authority seems wrong to me. For regularity, you should be submitting "*foo". @ is syntactically and semantically separate from foo (they identify two separate authorities, among other things), so it seems odd we should submit @foo. 1.0 resolution specifies adding a . (which would now become a *) and I think we should continue to use that rule for resolution absent some compelling reason. -Gabe __________________________________________________ gwachob@visa.com Chief Systems Architect Technology Strategies and Standards Visa International Phone: +1.650.432.3696 Fax: +1.650.554.6817 > -----Original Message----- > From: Lindelsee, Mike [mailto:mlindels@visa.com] > Sent: Tuesday, August 24, 2004 9:58 AM > To: xri@lists.oasis-open.org > Subject: RE: [xri] RE: GCS chars and star in XRI authority resolution > > > While the ABNF is nominally simpler using the production > below, it makes XRIs less regular and harder to understand > from a human perspective. If we allow "@!", I belive that we > need a very strong reason not to also allow "@*". > > Mike > > > -----Original Message----- > > From: Drummond Reed [mailto:drummond.reed@cordance.net] > > Sent: Monday, August 23, 2004 5:56 PM > > To: Lindelsee, Mike ; xri@lists.oasis-open.org > > Subject: RE: [xri] RE: GCS chars and star in XRI authority > resolution > > > > > > In retrospect I believe we erred in the 1.0 BNF in allowing > > what was then > > dot (and is now star) after a GCS character. I believe a > > cleaner approach in > > XRI 1.1 would be the following rationale: > > > > 1) All the GCS chars except "!" are "proxies" for "*", in > > that they default > > to a reassignable subsegment. > > > > 2) Therefore, there is no need for * following a GCS > character. It is > > redundant - the equivalent of "**", which makes no sense. > > > > 3) Therefore the simplest rule, which eliminates any > confusion and any > > chance of false negatives in a equivalence comparision, is > > > > GCS-authority = gcs-char [ "!" ] [ nz-segment ] > > > > Also, to keep XRI resolution consistent, the GCS char would > be treated > > exactly the same as star in subsegment resolution, i.e., it would be > > submitted as part of the string being resolved when resolving > > against a GCS > > root. For example, when resolving "@foo*bar", the string > > submitted to the > > "@" authority would be "@foo", and the string submitted to > the "@foo" > > authority would be "*bar". > > > > =Drummond > > > > > > -----Original Message----- > > From: Lindelsee, Mike [mailto:mlindels@visa.com] > > Sent: Monday, August 23, 2004 3:57 PM > > To: xri@lists.oasis-open.org > > Subject: [xri] 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 > > > > > > > > > > > > > > > > > To unsubscribe from this mailing list (and be removed from > > the roster of the > > OASIS TC), go to > > http://www.oasis-open.org/apps/org/workgroup/xri/members/leave > > _workgroup.php > > . > > > > > > > > > > To unsubscribe from this mailing list (and be removed from > > the roster of the OASIS TC), go to > > http://www.oasis-open.org/apps/org/workgroup/xri/members/leave > > _workgroup.php. > > > > > > To unsubscribe from this mailing list (and be removed from > the roster of the OASIS TC), go to > http://www.oasis-open.org/apps/org/workgroup/xri/members/leave > _workgroup.php. > >
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