RE: [xri] subject sets (was: Minutes: XRI TC Telecon 2-3PM PTThursday 2009-07-16)

[Eran Hammer-Lahav <eran@hueniverse.com>]

> -----Original Message-----
> From: Will Norris [mailto:will@willnorris.com]
> Sent: Tuesday, July 28, 2009 2:45 PM
> To: XRI TC
> Subject: [xri] subject sets (was: Minutes: XRI TC Telecon 2-3PM PT
> Thursday 2009-07-16)
> 
> (Let's NOT continue propagating the "Minutes:" subject, please... it's
> rather confusing)
> 
> I'll let the discussion with Scott run its course, but wanted to chime
> in with a couple of questions on this proposal:
> 
> Regarding extensibility, are we intending the "set" attribute of
> <Subject> be extensible with new values?  I know we are only planning
> to define one, "beginswith".  If we ARE intending it to be extensible,
> should we not use URI based values, so as not to necessitate the
> creation of a value registry?

Does XML namespace work for attribute values? I rather avoid a registry and avoid a URI value...
 
> Since <Subject> is used both at the XRD level and at the <Link> level,
> has any thought been giving to ramifications of having a subject set
> at the <Link> level?  It might simply not make sense, it might be
> perfectly valid, I'm not sure.  Just wanted to make sure we thought
> through that.

It is perfectly valid because you are giving a hint (or requirement, if used for trust) as to what to expect on the other side. Since the other side can have a set, so can a Link. This point seems to favor a single element for simplicity.

EHL