Re: [xri] Issue 1: Clarifying * Semantics

[Fen Labalme <fen@idcommons.org>]

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
> 
> 
>