RE: [xri] Issue 1: Clarifying * Semantics

["Dave McAlpin" <Dave.McAlpin@epok.net>]

Actually, a GCS character is not a sub-segment per the BNF, but it
certainly has the same characteristics as a sub-segment and is defined
as a "qualified sub-segment" in the resolution section. If we view
xri:@:1010 as having two sub-segments, there's no question that a) : is
a sub-segment separator in xri:@:1010 and b) there's an implied
reassignable sub-segment separator in xri:@1010.

Dave

> -----Original Message-----
> From: Fen Labalme [mailto:fen@idcommons.org]
> Sent: Thursday, July 08, 2004 11:11 AM
> To: Dave McAlpin
> Cc: xri@lists.oasis-open.org
> Subject: Re: [xri] Issue 1: Clarifying * Semantics
> 
> Colon is IMO *not* a subsegment separator in xri:@:1010 - rather, the
> initial
> GCS char is by definition a subsegment, and the colon is a decorator
that
> indicates persistence.  Note that in xri:@1010, again there are two
> subsegments, the GCS character and a reassignable subsegment.
> 
> Fen
> 
> 
> Dave McAlpin wrote:
> > I was addressing Drummond's point about the difficulty of parsing. I
> > just pointed out that the difference in complexity of an XRI parser
is
> > negligible between the current and the proposed syntax. Do you
disagree
> > with that?
> >
> > As to the clarification of : as a separator, I think there's a
> > misunderstanding here. Colon is _always_ a subsegment separator. In
> > xri:@:1010, there are two subsegments, @ and 1010. In xri:@example
there
> > are two subsegments, @ and example. Under both the current syntax
and
> > the new proposal, there's an implied * between @ and example in
> > xri:@example. If that genuinely confuses users (which I don't think
it
> > does, it's simply an ignorable technicality), then we'd have to make
it
> > explicit as xri:@*example. That's what I was pointing out (somewhat
> > facetiously) in my second comment below.
> >
> > Dave
> >
> >
> >>-----Original Message-----
> >>From: Fen Labalme [mailto:fen@idcommons.org]
> >>Sent: Thursday, July 08, 2004 10:38 AM
> >>To: Dave McAlpin
> >>Cc: xri@lists.oasis-open.org
> >>Subject: Re: [xri] Issue 1: Clarifying * Semantics
> >>
> >>Dave McAlpin wrote:
> >>
> >>>As we've pointed out before, the thing that makes parsing and
> >>>interpreting XRIs difficult is cross-references. The difference
> >
> > between
> >
> >>>the two options we're currently discussing is negligible.
> >>
> >>While I agree that cross-references are the truly hard part, the
> >
> > proposed
> >
> >>simplification is *not* negligible.  Rather, the change greatly
> >
> > clarifies
> >
> >>the
> >>meanings of : and *.  The first (an initial colon) becomes a simple
> >>decorator
> >>(I like that term) that denotes persistence - it is no longer
> >
> > *sometimes*
> >
> >>a
> >>separator.  The second (an initial star) now acts simply as a
> >
> > separator,
> >
> >>and
> >>no longer must be implied in places that it does not appear.
> >>
> >>
> >>>As for simplification of the rules, if implied * is confusing let's
> >
> > just
> >
> >>>require it. In other words, keep the current interpretation of *
and
> >>>change xri:@example/foo to xri:@*example/*foo, comparable to
> >
> > xri:@:3/:4.
> >
> >>>This is a much simpler change and has the benefits you mention
> >
> > below.
> >
> >>This would be dreadful.  Don't forget that the reason we're changing
> >
> > from
> >
> >>dot
> >>to star is for better human readability!
> >>
> >>Fen
> >
> >
> >