RE: [xdi] XDI/XRI Question

["Drummond Reed" <drummond.reed@cordance.net>]

Bill, it is to answer questions like this that the XRI TC needs to finish
the XRI Primer. I'm cc'ing the XRI TC on my response so folks in both forums
can help.

First, I don't mean to be dense, but I'm not sure I understand what you mean
by "@pin" or "@pin context". I may just not know the lingo of the
application area you are dealing with.

I can start with the following simple guide, though. The XRI global context
symbol "@" is used for organizational identifiers, "=" for personal
identifiers, and "+" for general identifiers (generic concepts like
"+email"). In addition, these can be combined to provide context using the
cross-reference syntax (nested parentheses).

I find it helpful to actually use the parentheses to conceptually organize
all the identifiers in the proper context, then decide which parens can be
eliminated to still have conformant XRI syntax. Using this approach, the
overall formula for expressing something like "Bill's email" where "Bill" is
identified by a cell phone number would conceptually look like this:

	=	(cell phone number for Bill)	/	(identifier for desired attribute)

This is because:
* The highest level context is that this is data controlled by an individual
(Bill), thus the global context is "="
* The second step is the identifier used to identify Bill in this context,
in this case a cell phone.
* The forward slash indicates you are looking for an attribute of this
resource
* The final identifier is the name of that attribute.

Applying this to your specific use case, where the identifier for Bill is a
cell phone number, would produce:

	=(tel:+1.206.555.1212)/(+email)

In this case the cross-reference under "=" is a telephone number expressed
using the "tel" URI scheme, and the name of the attribute being requested is
an attribute that is generically known as "email".

Hope this helps. Feel free to fire off questions, as they will all be fuel
for developing the XRI Primer.

=Drummond




-----Original Message-----
From: Barnhill William [mailto:barnhill_william@bah.com]
Sent: Wednesday, February 25, 2004 4:16 PM
To: xdi@lists.oasis-open.org
Subject: [xdi] XDI/XRI Question

I'm trying to get a better understanding of XRI by formulating a list of
simple real world use cases, and wondered if I could bounce one off the
list.

Would I represent the description "Bill's email", where @pin context was
resolved by some third party using cell numbers or some other pin, as
xri:@email.(@pin.=Bill)?

Actually I imagine that would be "The email that is Bill's" and "Bill's
email" would be xri:(@pin.=Bill).@email, right?

Subtle difference, but unless one is an alias/synonym for the other then
the authority first contacted for resolution would be different in the
two cases, yes?  Which case above would be the preferred form?

Thanks,

Bill Barnhill