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: markus.sabadello@gmail.com [mailto:markus.sabadello@gmail.com] 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

xdi message