Steve,
I apologize but do not have your background in graph
theory. How does "
In summary, the
convention that “$” is not going to reassign the local identifier “1” to “the
concept of the real number pi” has nothing to do with assigning markus assigning
the identifier =markus$v!1 to a mutable collection.
" apply?
I think you're suggesting our
examples should be in the vein of =markus$v$1, is that
correct?
Bill
From: Steven Churchill
[mailto:]
Sent: Friday, February 22, 2008
4:05 PM
To: 'Markus Sabadello'; Barnhill, William [USA]
Cc:
;
Subject: RE:
[xdi] Groups - Comments about XDI versioning
(Draft-Contrib-OASIS-XDI-versioning.pdf) uploaded
Reassignability is a
convention that applies only at the XRI namespace
level.
For example, an XRI
namespace registry might do this:
Mint a new XRI authority (record)
for a paying customer.
Assign it a local (bang) inumber
to be returned as the final subsegment of it’s CID.
If the given XRI
namespace registry is well-behaved, then it will follow the convention that it
will not re-use the authority with the local inumber for another customer. (It
won’t re-assign it to another customer.)
So, in this case, this
notion of “not re-assigning” is a convention to be followed by well-behaved XRI
namespace registries.
---
So what about the name
space “$” and the child “1”. It would probably be a good convention that if “$”
assigned the child authority named “1” to the concept of the integer value 1 then it shouldn’t at
some later date assign the local identifier to some other concept (like
the real number pi, for example.)
---
In summary, the
convention that “$” is not going to reassign the local identifier “1” to “the
concept of the real number pi” has nothing to do with assigning markus assigning
the identifier =markus$v!1 to a mutable collection.
~
Steve
From:
[mailto:] On Behalf Of Markus Sabadello
Sent: Friday, February 22, 2008 8:11
AM
To: Barnhill, William
[USA]
Cc:
;
Subject: Re: [xdi] Groups - Comments about
XDI versioning (Draft-Contrib-OASIS-XDI-versioning.pdf)
uploaded
Hmm yes right, ! is persistent, so it
doesn't work for mutable collections, I didn't think about that. If I have 5
e-mail addresses, one of them may get deleted. But in versioning persistence is
what you want (version 2 will never change or go away..). So maybe the solution
is to support both ! and *.
Versioning example
(persistent):
=markus/$has!5/$v <-- in the metagraph
model, $has is for composite subjects, right? -->
=markus$v!1
...
=markus$v!2
..
=markus$v!3
..
Multiple
e-mails example (reassignable):
=markus/$has$a*5/+email <-- in
the metagraph model, $has$a is for predicates, right?
-->
+email*1
..
+email*2
..
+email*3
..
Anyway, just a
thought. It would be great if somehow the same mechanism could be used for "I
have 5 versions" and "I have 5 e-mail addresses".
How would the
+yesterday construct work? Would the endpoint look at timestamps on the
individual version snapshots and find out which one to
return?
Markus
On Fri, Feb 22, 2008 at 10:04 AM, Barnhill, William
[USA] <>
wrote:
Hi
guys,
You both have some very good and interesting points. Just saw this
though and wanted to send off a thought: while ! syntax is easier to understand
and read imho, it also might lead to a problem. If you are using it to things in
a modifiable collection your collection order could change, or you could insert
someplace other than the tail of the collection. This would mean you would need
to reassign your ! identifiers, but are they reassignable? $n would get around
that and lower the verbosity closer to ! level.
For versioning, I like
best the following:
=drummond/$has/$v (this says that
=drummond is versioned)
=drummond/$v/5 (this says the current
version is 5)
(=drummond/$v/5)/$is/!4
I think $v should by
default be a # in the dictionary. If you want to access yesterday's last version
you can do
=drummond/$v+yesterday
which accesses statements of the
form
=drummond/$v+yesterday/5
(=drummond/$v/5)/$is/!4
What do you
think?,
Bill
-----Original Message-----
From:
on behalf of Markus
Sabadello
Sent: Thu 2/21/2008 10:45 PM
To:
Cc:
Subject: Re: [xdi] Groups -
Comments about XDI versioning (Draft-Contrib-OASIS-XDI-versioning.pdf)
uploaded
Heya Giovanni,
Since I already tried to implement the
versioning described in the XDI RDF Model v8 doc, it's interesting for me to
read your comments about this..
- Regarding the use of $num instead of !
to index things, I think it's mostly a matter of taste. Both would work fine I
think. One thought I am having is that subsegments like !1, !2, !3 do exist in
XRI resolution too. I.e. there are some authority resolution servers that use
these number-like subsegments (and not ip address-like subsegments like
!203.173.1276.1663)..
- Regarding the number of versions, can I ask you
something?
Maybe you can take a quick look at this URL: http://graceland.parityinc.net/xdi-endpoint/hibernate-graph-ver/=drummond
As
you can see there are the following two
statements:
=drummond/$has/$v (this says that =drummond is
versioned)
=drummond/$v/!5 (this says the current version is
5)
I'd like to understand how you would do it instead.
Would you
say this?
=drummond/$has$num$5/$v
Or
this?
=drummond/$has$5/$v
Just trying to understand it correctly.. I
like the idea very much, it makes versioning a bit simpler and more consistent
with other constructs..
Note to Drummond: We were talking about how to
express multiple values of an attribute (e.g. =markus has multiple +email
addresses). After reading Giovanni's comments, it appears to me that versioning
may just be another instance of that same problem. I.e. there's no difference
between saying =markus has 5 +email addresses, and saying that =drummond has 5
$v ersions. I agree with Giovanni that the same construct should be used in both
cases.
- I don't understand why I would use the comparison operators like
$greater in versioning.. What would be a practical use case for this? But in
general I think these operators can be very useful..
Markus
On
14 Feb 2008 13:53:29 -0000, <> wrote:
The
document named Comments about XDI
versioning
(Draft-Contrib-OASIS-XDI-versioning.pdf) has been submitted by
Giovanni
Bartolomeo to the OASIS XRI Data Interchange (XDI) TC document
repository.
Document Description:
A first draft of comments on XDI
versioning syntax
View Document Details:
http://www.oasis-open.org/apps/org/workgroup/xdi/document.php?document_id=27179
Download
Document:
http://www.oasis-open.org/apps/org/workgroup/xdi/download.php/27179/Draft-Contrib-OASIS-XDI-versioning.pdf
PLEASE
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