RE: [xdi] on global cross references and the link contract use case

Sorry, Les, you’re right - I didn’t
mean to imply that it could ignore syntax-based policies.

 

=Drummond 

 

From: Chasen, Les
[mailto:] 

Sent: Wednesday, November 26, 2008
8:12 PM

To: Drummond Reed;


Cc:
; 

Subject: RE: [xdi] on global cross
references and the link contract use case

 

Drummond says
“IMHO the authority of an authority server
is sacrosant. It can apply any policy it wants to produce the next XRD.”

 

Hmmm except for where we have already put
policies in place.  For example

 

= personal

@ organization

+ dictionary

$ system

* reassignable

! persistent

 

 

From: Drummond Reed
[mailto:] 

Sent: Wednesday, November 26, 2008
7:11 PM

To: Chasen, Les; 

Cc:
; 

Subject: RE: [xdi] on global cross
references and the link contract use case

 

What the @cordance authority service does
when given the subsegments…

 

           
=drummond

           
*(=drummond)

 

…is up to the @cordance authority
server. I agree that @cordance authority server could decide to consult another
authority server in its response, but it still controls the response it its own
context no matter where it gets the XRD or what it puts in it. For example, it
could:

 

1) Have a policy that both of the
subsegments above are synonyms in its context and that they return the same
XRD.

2) Have a policy, as Les suggests, that
*(=drummond) will return the XRD (or selected SEPs from XRD) from the =
registry. (See note below.)

3) Have any other policy that applies to
global subsegments and/or local cross-references.

 

IMHO the authority of an authority server
is sacrosant. It can apply any policy it wants to produce the next XRD. What
matters is that:

 

A) Parsing of the next subsegment to be
resolved is always 100% unambiguous for a resolver. 

B) The resolver always hands the authority
server EXACTLY the next subsegment to be resolved (or all remaining subsegments
to be resolved in lookahead resolution).

C) The authority server return a valid XRD
(or an XRDS in the case of lookahead resolution).

 

=Drummond 

 

From: Chasen, Les
[mailto:] 

Sent: Wednesday, November 26, 2008
10:03 AM

To: 

Cc:
; 

Subject: Re: [xdi] on global cross
references and the link contract use case

 

I need to stick with simple examples and in this case there
is only one authority, @cordance, in question. under the current proposal
@cordance is asked for both =drummond and *(=drummond) and it returns its own
xrd if one exists within @cordance. We have never discussed whether @cordance
may go to the = authorty server for drummond when it is contained within
*(=drummond). I think that maybe interesting behavior.

--------------------------

http://xri.net/=les.chasen

From: John Bradley 

To: Chasen, Les

Cc:
 ;  

Sent: Wed Nov 26 12:44:00 2008

Subject: Re: [xdi] on global cross
references and the link contract use case

Les,

 

I started off with that position.   I now think they are
separate queries to the next authority server.

 

I think that the parenthesized statement may contain multiple
subsegments is the important thing.  

Once we have a way to encapsulate multiple subsegments to be handed to
an authority server it is hard to stop someone from only putting in a
single subsegment. in the cross ref.

 

I think the simple principle is that things
in parenthesis are opaque to the resolver and handed to the next
authority server and things not in parenthesis are resolved left to
right one subsegment at a time.

 

I also don't think that in ether case @cordance is being asked anything
about the global =drummond if one exists.

 

In the first case the authority server for @cordance is being asked for
a XRD for the subsegment =drummond the = is treated as part of the subsegment
itself

In the second  case the authority server for @cordance is being
asked for a XRD for the subsegment  *(=drummond) 

 

I think the latter could be taken that the authority server may look
someplace else to get the XRD for the cross reference.

I think in the former case =drummond is a subsegment in its
authority server.

 

The question is if it is just a regular subsegment is using = as a
separator going to confuse people.

 

=drummond is just a regular subsegment with
some inference by Cordance that its =drummond has something to do
with the global =drummond though XRI makes no such claim other things using XRI
like XDI may.

 

 

John B.

 

 

On 26-Nov-08, at 9:23 AM, Chasen, Les wrote:

 

Let's not complicate this with +phone. My question is does
@cordance return a different xrd for =drummond and *(=drummond)? This proposal
says yes. I disagree with this behavior. I think @cordance is being asked for
its representation of =drummond in both cases.

-------------------------- 

http://xri.net/=les.chasen 

 

From: John
Bradley 

To: Chasen, Les 

Cc: 
;  

Sent: Wed Nov 26 12:11:59 2008

Subject: Re: [xdi] on global cross
references and the link contract use case 

 

From a XRI resolution perspective I see a difference in what
@cordance's authority server is asked for.

 

@cordance=drummond                                 
, @cordance is asked for the XRD for =drummond

@cordance=drummond+phone          
, @cordance is asked for the XRD for =drummond
, @cordance=drummond is asked for the XRD for +phone

@cordance*(=drummond)                 
, @cordance is asked for the XRD for *(=drummond)

@cordance*(=drummond+phone)     
, @cordance is asked for the XRD for *(=drummond+phone)

 

Parenthesis in the first segment tell the resolver to treat the contents
as an opaque string and pass it to the next authority server.

 

The resolver Parenthesis in the path are
not significant to the resolver they would
be matched during service selection as they are now.

 

One thing we did start talking about at the F2F is what the syntax to
indicate special processing on a cross reference.

 

An example:

$XRD*(https://boing.com)*marty

 

Is $XRD a node that has as its authority service one that performs XRD
resolution on the next subsegment.

 

So is a $ word in XRI resolution a node that points to
a specialized authority service?

 

Certainly a resolver has the option
of shortcutting resolution through querying the $XRD
authority server if it understands the $XRD word.

 

Under Drummond's proposal we do have to have a theory about what + and
$ in the first subsegment resolve to.

 

John B.

 

 

On 26-Nov-08, at 6:51 AM, Chasen, Les wrote:

 

Hi Giovanni -

A cross reference is putting the thing cross referenced inside the context of
the xri that contained the cross reference. Terminology in this proposal has
been changing but the thing that hasn't is that in both cases the outer
authority is returning its xrd for the reference. That is, in the example
below, cordance is returning its xrd for =drummond. 

@cordance=drummond

@cordance*(=drummond)

So we only support the 'inside' (or better stated container) concept. Now it
may be interesting to consider a resolution process which rather than asking
@cordance for =drummond we ask = for drummond. Today that does not exist.

Have a happy thanksgiving.

Thanks

Les

-------------------------- 

http://xri.net/=les.chasen 

 

From: Giovanni
Bartolomeo 

To: Chasen, Les 

Cc: XDI 

Sent: Wed Nov 26 09:35:43 2008

Subject: RE: [xdi] on global cross
references and the link contract use case 

 

Hello Les,

First, thank you for having read the contribution! Unfortunately I'm probably not
the best person which can answer your question, as I'm not an expert of XRI2.0.
I limited to develop my contribution in the scope of the current proposal (
http://wiki.oasis-open.org/xri/XriThree/GcsDelimiter), which, I personally
support for one specific reason: http://lists.oasis-open.org/archives/xri/200811/msg00043.html.

I think Drummond's reply http://lists.oasis-open.org/archives/xdi/200811/msg00031.html
is a good technical explanation of this, expecially the last statement: in an ordered set, you are not referencing across contexts.
The context is the ordered set itself. For example, in $sig$d, the context for
$d is $sig. Which I understand as follow: put an object inside a
context is not exactly the same as referencing it from that context). 

The core of this issue - that's my guess and not a technical explanation
-  is probably that XRI2.0 did not consider the need to "put an
instance of an object inside a
context", but just to "cross reference" it. That is instead a
fundamental capability for XDI (and for any human or machine understandable
language).

I'll be happy to answer any further questions you might have on the contents of
the contribution itself.

Kind Regards,

Giovanni

At 13.36 25/11/2008, Chasen, Les wrote:

Hi Giovanni.  I had a chance to read this.  While I like what
you guys

are doing with link contracts I fail to understand why all of these

examples do not work with XRI 2.0 style cross references.  

> -----Original Message-----

> From: Giovanni Bartolomeo [
mailto:]

> Sent: Wednesday, November 19, 2008 12:02 PM

> To: XDI

> Subject: [xdi] on global cross references and the link contract use

> case

> 

> Hello,

> 

> some weeks ago I mentioned that I was playing a bit with the

> semantics of link contracts. Better to say, with the global cross

> references applied to the link contract use case. After the issue of

> XDI RDF model v.11, I put my thoughts in a document which you can find

> below.

> Maybe just semantic nuances, but your comments will be welcome.

> 

> Thanks,

> Giovanni

No virus found in this incoming message.

Checked by AVG - http://www.avg.com 

Version: 8.0.175 / Virus Database: 270.9.10/1811 - Release Date: 25/11/2008
8.29