This doesn't make sense
to me. The rules for relative resolution of URI segments is based on the
following criteria:
1) Presence of the
segment delimiter character at the start of a relative URI, e.g.,
"/abc"
2) Absence of the
segment delimiter character at the start of a relative URI, e.g.,
"abc".
Why would the rules for
relative resolution of XRI subsegments be any different, i.e., be based on
anything except presence or absence of the subsegment delimiter
character?
You mention that
"/:1234" could mean "the same thing" (I assume that means "the same thing as a
relative subsegment"). That can't be true if "/:1234" can also mean a relative
segment, as it does today in XRI 1.0 syntax. Then an application wouldn't be
able to distinguish between a relative segment and a relative
subsegment.
It is of course
possible that we could introduce another character (different than the
persistence decorator character, or else you run into the original problem
described in my message) to be the prefix character for a relative subsegment.
But why would we do that to make XRI syntax even more complicated when the
obvious rule, per the pattern established by URI syntax, is to use the presence
or absence of the subsegment delimiter character?
=Drummond
From: Dave
McAlpin [mailto:Dave.McAlpin@epok.net]
Sent: Tuesday, August 03, 2004 8:14
PM
To: Drummond Reed;
xri@lists.oasis-open.org
Subject: RE: [xri] [star syntax issue]
Clarifying the argument
They fact that the
syntax *:1234 means "resolve this relative to a subsegment, not a segment" is
arbitrary. There's no reason ;:1243 or .../:1234 or some other combination of
characters couldn't mean the same thing. I don't think relative
subsegment resolution has any bearing on the star syntax
issue.
From: Drummond
Reed [mailto:drummond.reed@cordance.net]
Sent: Tue 8/3/2004 9:35 PM
To: xri@lists.oasis-open.org
Subject: [xri] [star syntax issue]
Clarifying the argument
[Note: on the XRI Editor's SC call today, it was agreed
that Dave McAlpin,
Mike Lindelsee, Fen Labalme, and myself would take point
on trying to come
to closure on the star syntax issue, explained in an
earlier post today (see
http://lists.oasis-open.org/archives/xri/200408/msg00006.html).
We also
agreed that as much of this discussion as feasible would take place
on the
list. If any telecons are needed, we'll post minutes to the list.
For
filtering purposes, we will try to prefix the subject lines of all
messages
on this thread with "[star syntax issue]". =Drummond)
This
first message is clarify that the writeup posted earlier today
(http://lists.oasis-open.org/archives/xri/200408/msg00006.html)
was not
meant on its face to propose new relative resolution rules for XRIs.
Dave is
correct in his message below that, as discussed on the XRI Editor's
SC call,
it may result in our decision to define a new relative resolution
algorithm
for subsegments in XRI 1.1.
However the key point of the
argument in the original posting was that if we
do not separate the roles of
subsegment delimiter and persistence decorator
into two separate syntactic
characters in XRI 1.1 syntax, then we preclude
the ability of any application
using XRIs to define its own relative
subsegment resolution rules, e.g.,
rules that can differentiate between:
a) persistent relative XRIs that
are relative to the current node, e.g.,
":123", and
b) persistent relative
XRIs that may be relative to some higher subsegment,
e.g., "*:123" (if star
is the subsegment delimiter character and colon the
persistence
decorator.)
If the only syntax available for expressing relative
persistent subsegments
is ":123", we have precluded applications from being
able to do (b) above.
This would effectively be the same as URI syntax
defining that ":123" and
"/:123" are equivalent. If that was the case, it
would be impossible to have
resolution rules that were different for ":123"
and "/:123".
So it is not an issue of whether we need in XRI 1.1 to
extend URI relative
resolution rules by defining relative subsegment
resolution rules (which we
may or may not decide to do.) The issue at a
syntax level is whether ANY
application that uses XRIs may EVER want to
define such resolution rules.
Even if XDI did not exist today (and have a
clear and compelling need to use
relative subsegment resolution rules
immediately), the effect of not
separating the syntax character used to
delimit subsegments from the syntax
character used to indicate ("decorate") a
persistent subsegment would
preclude this capability in any future
application.
Does this argument leave any question that we must separate
these roles in
XRI 1.1?
=Drummond
-----Original
Message-----
From: Dave McAlpin [mailto:Dave.McAlpin@epok.net]
Sent:
Tuesday, August 03, 2004 3:47 PM
To: Drummond Reed;
xri@lists.oasis-open.org
Subject: RE: [xri] XRI 1.1 issue: star syntax
semantics
It's too late to respond to the technical issues here before
the call,
but I think we need to address the proposed requirement for
relative
resolution of subsegments before we modify syntax to support
it.
1) Should we consider a new relative resolution algorithm
for
subsegments?
2) If we should, what are the rules? Just a list of
examples would be
instructive.
3) How do we reconcile these rules with
relative resolution as defined
by 2396bis? In other words, if a non-XRI aware
processor applies
standard resolution rules, is the result equivalent to the
rules
proposed in 2? If not, what are the implications for URI
compatibility?
I think we need to address these issues independently
before we suggest
that we've somehow demonstrated that * must be a
separator.
Dave
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