RE: [xdi] Implications of removing $has$a

Markus,

 

Thanks for researching this – it is
VERY useful info. I too did a search in several places for $has$a usages, but I
forgot to look at versioning. 

 

The other place we have been using both
$has and $has$a is in dictionary defintions. And there it is clearly useful. In
thinking about it more since posting that message on Monday, I’ve come up
with several other places where not having $has$a would actually be a problem.

 

The good news is that I think there is a
corresponding definition for $has$a which works nicely with the new definition
of $has, and which would yield exactly the uses for $has$a that we’ve
found useful in versioning and dictionaries, but which would not introduce the
RDF problem we had before. I don’t have time to write it up right now,
but I’ll post something before tomorrow’s telecon, so we can go
over it on the call.

 

=Drummond 

 

From:
 [mailto:] On Behalf Of Markus Sabadello

Sent: Wednesday, May 06, 2009 1:53
PM

To: OASIS - XDI TC

Subject: [xdi] Implications of
removing $has$a

 

Hi,

I tried removing $has$a from XDI4j (http://wiki.eclipse.org/XDI4j) to see what it breaks.

Actually I found only one piece: Versioning

In XDI Versioning we were using $has for "version snapshots" and
$has$a for "version logs".

- A "version snapshot" is a complete copy of a subject at a given
version

- A "version log" is a copy of the XDI message that produced the
given version

We had a nice wiki page about this, but somehow I can't find it right now.

Anyway, here is an example XDI document with 2 versions of =markus, complete
with "version snapshots" and "version logs":

=markus

    +name

        "Markus Sabadello"

    $has

        $v

    $v

        !2

    +friend

        =drummond

=markus$v

    $has

        !2

    =markus$v!1

        /

            =markus

               
$add

               
    /

               
        =markus

               
            +name

               
               
"Markus Sabadello"

    $has$a

        =markus$v!2

    =markus$v!2

        /

            =markus

               
$add

               
    /

               
        =markus

               
            +friend

               
               
=drummond

=markus$v!1

    +name

        "Markus Sabadello"

=markus$v!2

    +name

        "Markus Sabadello"

    +friend

        =drummond

My guess is that we can simply leave out the one $has$a statement, since it
doesn't really add much additional information anyway. But maybe someone has a
better idea...

Markus