Jeni's Musings

During my keynote at XML Prague (the video might make more sense than the slides on their own; there are notes on the slides but Slideshare doesn’t do well with Keynote), I talked about how the advantages of using chimeras created from two formats with different underlying models are seldom outweighed by the disadvantages. RDF/XML gets knocked so frequently it’s not even much fun to do it any more, but I’ve applied the same arguments to JSON-LD in the past. My argument was that RDF, XML, JSON and HTML should each be used individually for their strengths rather than trying to find a middle ground that rarely satisfies anyone.

Leigh Dodds’ post on principled use of RDF/XML makes the point that RDF/XML can be useful when it is used in a regular, principled way. And in fact, I am using RDF/XML extensively in my work on Expert Participation for legislation.gov.uk, though slightly differently from how Leigh describes. What I want to explore in this post is when and how it makes sense to use RDF/XML and how that might translate into usage of JSON versions of RDF. The key point I want to make is that RDF chimera are roads, not destinations, and when you’re choosing a road you have to think about the destination you’re aiming for.

One of the things that’s been niggling at the back of my mind since the schema.org announcement is how small a role search engine results plays in the wider data sharing efforts that I’m more familiar with in my work on legislation.gov.uk, and more generally how my day job experience differs from (what seem to be) more common experiences of development on the web. In this post, I’m going to talk about that experience, and about the particular problems that I see with the coexistence of microdata and RDFa as a result.

Registration has just opened for this year’s XML Summer School, held in Oxford on 20-25th September. I’m teaching a couple of sessions and helping with a workshop on the “XSLT, XSL-FO and XQuery” track along with Bob DuCharme, Michael Kay and Priscilla Walmsley. It’s one of my favourite events, for three reasons:

• I get to listen to experts talk about particular technologies in depth. The sessions are particularly good because they’re provided by people who don’t just spend all their time training, but actually practice what they’re talking about, and therefore positively relish the kinds of discussions that normal trainers might shy away from.
• I get to meet a whole bunch of people who are using XML in different areas: publishing, healthcare, government, you name it. In that way it’s like a conference: many of the most useful conversations happen during the breaks or at the bar.
• I get to go punting, visit Oxford’s best pubs and dress up for a formal dinner — more social engagements in a single week than I usually have in a year!

I know a lot of beginners go to the XML Summer School for the introduction course, but to me the real value is for people who are actually using XML on a day to day basis and want to keep on top of the latest tools and technologies that will actually help them do their jobs. I learn something new every year.

Anyway, I wanted to blog about it because there’s a discount on registration up until 30th June. Grab ‘em while you can!

For the last several months, I’ve been working on a project at TSO for publishing UK legislation using a native XML database (eg eXist or MarkLogic Server) with some middleware (eg Orbeon or Cocoon). It’s a powerful and flexible approach that’s built on declarative languages like XQuery, XSLT, and XML pipelines; you can see it in action with the Command and House Papers demo.

But the killer platform isn’t quite here yet, partly because the specs aren’t quite done. Both Orbeon and Cocoon use XML pipelines, but they use different languages to define them; XProc is just around the corner. XML databases are all over the place in their conformance to XQuery, its optional features and the not-quite-finalised specs for free-text searching and updating.

People talk about how productive you can be using Ruby on Rails or Django, and they work great for publishing data you can store in a relational database. What we need is a similarly easy-to-use platform for document-oriented, XML-based content. This is my wish-list.

This is the talk I prepared for the UKGovWeb Barcamp, in blog form. It’s probably better this way. Most of what’s written here seems blindingly obvious to me, and probably to most readers of this blog, but maybe Google will direct someone here who finds it useful.

Working with public-sector information on the web, one of the things that I take an interest in is making government data freely available for anyone to re-present, mash-up, analyse and generally do whatever they want to do. This post is born out of a feeling that the people who control data don’t realise that the smallest changes can be beneficial: they don’t need to do everything right now, just something.

In my last post I talked about different techniques for representing overlap within XML. One technique is fragmentation. In the work that I’ve been doing, I’ve been using milestone-based formats similar to ECLIX, but my eyes were opened at the GODDAG workshop: fragmentation would make overlap so much easier to process in XSLT, especially when dealing with localised overlap such as revision or comment markup.

But how could fragmentation be used with full-on overlap? I had a little play and came up with some XSLT to demonstrate.

The Free Our Bills campaign was launched recently in the UK. Some of the comments I’ve seen about the campaign makes me think that it might be helpful if people understood more about how Bills and legislation get published in the UK. I thought I’d offer a bit of background based on my experience (though there are many people with more intimate knowledge of the processes involved; perhaps they’ll correct me when I get it wrong).

Another question to answer:

I’ve been reading about RDF, and I’m not sure in what situations it is more appropriate to use RDF over straight XML. I usually see RDF expressed as XML, but sometimes I see it written as language-independent functions (or methods).

Part of me is wondering if RDF is more appropriate for this project. What might the benefits be? And if it is, how difficult it would be to refactor it.

We just had photos taken of the children, and it’s put me in a reflective mood. Norm posted the other day about his experience with information/task management products:

Then it hit me.

None of them, with the notable exception of Tinderbox, seem to store the data in any open format. I was seriously considering one of these commercial black boxes for an important chunk of the data that drives my day-to-day life. The little voice in my head reacted viscerally when the observation was made: “What the hell you thinking, man! Stop that!”

A Ruby on Rails specialist friend and I are building a Web 2.0 application. I would say it’s “social networking for the dead” except that I doubt that description would be attractive to most people (my ex-Goth defacto being a rare exception), and it can be for the living too. It’s a bit like all those genalogy websites, except that our focus is on people’s social relationships as well as their familial ones.

(I should say that this is all very casual. We’re both fitting it in around our other responsibilities, and are mainly interested in working together, learning new things, and trying out all the best practices that everyone keeps talking about. So don’t think I’m becoming a dotcom entrepreneur or anything. Its got a very Web 2.0 name, and I’m only not telling you in case you start hitting our servers. We’re nowhere near ready for visitors.)