Neil's Place

November 24, 2002

4:36 PM RDFPath / RPath

There were some folks looking into building RDFPath, an XPath-like syntax for referring to RDF data, although it hasn't had any updates for over a year. The syntax is fairly general purpose though.

For the RPath language I'm using in the SWC, I probably have different goals, since the expressions are intended to be used in UI elements, like XPath expressions are used in XForms. As such, they don't connect to a giant database of info.

For example, I might use:

director[birthdate/year < 1950]

which in RPath would return all nodes of directors born before 1950, but that wouldn't make sense to use on a client, as a client wouldn't have a database of directors to scan through unless it sent the query off to some remote server.

But, given two RDF files sent to the client each describing a different movie, one could pick out cast members that starred in both using:

children(<movie1id>/cast) & children(<movie2id>/cast)

Thus, there needs to be a balance between making the expressions powerful, yet ensuring that they make sense and performance doesn't suffer as a result.

Comments ( 29 )

2:00 PM Real work

Hmmm. I seem to have gotten myself into a situation where I have to do some real paid-for work for a few weeks. So I might not get as much time to work on the SWC.

The only thing I've done lately is change the history panel to use labels instead of URIs, and started creating a dialog box for adding custom datasources.

I wonder how I am doing all this.

Comments ( 4 )

November 22, 2002

11:51 AM

MSN Instant Messenger doesn't allow one to set your Displayed Name to anything containing the string "employ". So, if your name is "Tom Temploy", you're out of luck.

Comments ( 5 )

November 20, 2002

11:55 PM A little history

Have been working some more on the Semantic Web Client. I've started adding some real UI to it. It's not polished yet and it is quite slow at times, but it is finally getting close to doing something useful. I've added a history sidebar that shows a list of all of the resources one has viewed. Double-clicking a history entry opens it in the main content area, modifying the XUL and what RDF it is bound to accordingly.

It now has three datasources, Movies, Word lookup and Mozilla Bookmarks. The image shows some of the items from each in the history sidebar.

Next, I'll get it so one can add any RDF datasource at all, and get it so that links between them properly display the right UI for the right data.

Comments ( 72 )

2:52 PM It won't happen again for 1000 years!

Is it just me, or doesn't there seem to be some kind of once-in-a-lifetime astronomical event every year?

Comments ( 8 )

November 17, 2002

4:20 PM RDF Library Updated

I have updated the RDF library in the XUL tutorial. I changed the way that datasources are loaded to make more sense. I also added functions to parse RDF from a string, and to serialize a datasource back to a string again. I also added more examples.

You can now do fun things like output your bookmarks as RDF:

var bookmarksRDF=newRDFDataSource("rdf:bookmarks").serializeToString();

Comments ( 37 )

November 14, 2002

10:16 PM

Anil Dash has updated Introducing the Microcontent Client. Interestingly, he even refers to the RDF stuff I've been working on, which, of course, is why I noticed the change.

Comments ( 1 )

November 13, 2002

11:55 PM Some XUL/JavaScript bits

Some useful bits of one may find useful.

Comments ( 47 )