RE: [xri] Updated 2.1 ABNF and global subsegments

Hi All,

 

Even though Drummond and I discuss his newer proposal 
and explore how to make it "work", I'm not promoting it. I still favor the 
earlier notion of compact syntax. We never fully got compact syntax to work, but 
I think we were close. I think that by limiting the scope of compact syntax to a 
single subsegment, lots of the problems would go away. I acknowledge that the 
compact syntax would only work for very simple xrefs, but that was its 
original intent, and I kinda like that intent.

 

I don't like the idea of trying to get rid of parens 
wherever we can, because even though they make an XRI longer, for more complex 
XRIs they help me understand the intent of the XRI - I actually think complex 
XRIs that include parens are more legible than ones that 
don't.

 

Regarding the question if "=$d*2006-02-17*(=example)" 
and 
"=($d*2006-02-17)*(=example)" mean the same thing, I agree that if they normalize to the same value they MUST 
represent the same resource. However, these examples just illustrate that we 
never completed the normalization rules and syntax. If we define the scope of 
compact syntax to be a single subsegment, then these two XRIs are definately not 
equivalent (although of course they may be 
synonyms).

 

I do like the idea that bang would no longer be a GCS. 
As a matter of fact, I'd like for bang to continue to evolve to the point that 
it is just an XRI minter's claim of persistence, and have noting to do with 
namespace. I'd like for two XRIs that differ only in bangs to be 
considered equivalent for comparison and resolution. Admittedly this idea is not 
fully baked. 

 

; 
CISSP 
Associate 
Technical Fellow - Cyber Identity Specialist 
Computing Security 
Infrastructure 
(206) 
679-5933 

 

From: Drummond Reed 
[mailto:] 
Sent: Wednesday, March 07, 2007 
1:37 PM
To: 'Chasen, Les'; 
Subject: 
RE: [xri] Updated 2.1 ABNF and global subsegments

Good points/questions, 
Les. See [=Drummond] inline.

 

From: Chasen, 
Les [mailto:] 
Sent: Wednesday, March 07, 2007 10:19 
AM
To: Drummond Reed; 

Subject: RE: [xri] Updated 2.1 ABNF and 
global subsegments

 

A couple of 
note/comments:

 

* another change that 
this includes but does not spell out is that ! is no longer a GCS 
character.

 

[=Drummond] Good point. 
Standard Example #10 on http://wiki.oasis-open.org/xri/XriCd02/GlobalSubsegments 
shows what happens under this proposal – the former ! GCS character (which by 
the XRI 2.0 ABNF had to be followed by a second !, so effectively it was always 
!!) is now a subspace under another GCS character. For example, the XDI.org !! 
registry would become a subspace of the @ registry, i.e., !!1000 would become 
@!!1000.

 

* One thing that 
confuses me is that the second instance of a global-subseg is a xref without 
parenthesis but is not called a xref.  

 

[=Drummond] That’s a 
good point that was also brought up by Laurie and Marty on our XRI $ Dictionary 
calls. It’s purely a semantic issue, but an important one. I went back and 
studied the v3 proposal ABNF closely, and I came up with a solution I really 
like: remove the usage of “xref” altogether. See my next message to the list 
with a full explanation of the v4 I just posted at http://wiki.oasis-open.org/xri/XriCd02/XriAbnf2dot1. 

 

* In this example 
=$d*2006-02-17=example how does that compare 
to =($d*2006-02-17=example) and 
=($d*2006-02-17)=example and 
=$d*2006-02-17(=example) and 
=($d*2006-02-17)(=example).  Do these 
all mean the same thing?  

 

[=Drummond] Marty and I 
went over this same question on our XRI $ Dictionary call yesterday. The first 
thing I need to point out is that, although we discussed not needing a delimiter 
before parentheses in the 2.1 ABNF, for good reasons Marty and I discovered, we 
do need to require one (either a GCS or LCS character). So the last two XRIs in 
your question should be =$d*2006-02-17*(=example) and 
=($d*2006-02-17)*(=example). 

 

[=Drummond] On the 
question of whether they all “mean the same thing”, there are two possible 
answers: a) yes, they represent the same resource because they *normalize to the same XRI*, or b) they 
MIGHT represent the same resource (i.e., be synonyms), but that can only be 
determined via resolution.

 

[=Drummond] For good 
reasons which we’ll talk about on tomorrow’s call, right now my answer would be 
the latter. But I plan to discuss this with Marty further before then (and if we 
come to solid conclusion, we’ll post it).

 

=Drummond 

 

 

From: Drummond 
Reed [mailto:] 
Sent: Tuesday, March 06, 2007 12:47 
AM
To: 

Subject: [xri] Updated 2.1 ABNF and global 
subsegments

 

XRI TC Members and 
Observers:

 

An update to the proposed ABNF for 
XRI Syntax 2.1 has been posted to the XRI TC wiki 
at:

 

            
http://wiki.oasis-open.org/xri/XriCd02/XriAbnf2dot1

 

This third draft incorporates 
feedback and suggestions from earlier drafts. In particular it now breaks the 
former xri-subseg (XRI subsegment) rule into two forms: global-subseg (global 
subsegment) and local-subseg (local subsegment). Global subsegments replace the 
former compact syntax proposal. A full explanation of global subsegments and how 
they would be treated by XRI resolution has been posted 
at:

 

            
http://wiki.oasis-open.org/xri/XriCd02/GlobalSubsegments

 

Note that the latter page still has 
a few TO-DOs at the end which I’ll fill in tomorrow. But I urge you to review 
both the proposed ABNF and the global subsegment proposal in preparation for 
this Thursday’s call.

 

Also, in a call I had with Les and 
Wil and Trung today, Wil took the action item to review the ABNF from the 
standpoint of the OpenXRI parser implementation. So he may come back with 
suggestions about how rule names might be refactored to best support 
implementation.

 

Please do send any feedback/comments 
directly to the list, as this is the last major outstanding issue for XRI Syntax 
2.1, so we want to close on this and begin drafting as soon as we can to be 
ready for final review at the OASIS Symposium starting April 
16.

 

=Drummond