RDF W3C Writing

It’s a beautiful fall and I’m stuck inside

he fall has been nice, but I haven’t been able to take advantage of the decent weather and pretty scenery. I have a book deadline next week for my new book for O’Reilly, The JavaScript Cookbook.

I can’t do much anyway, because my car is doing very odd things, and I no longer trust it for longer out of town trips. I know there’s a short somewhere, but every time I take it in, it costs me $500.00. But I’m getting a relay click in the dash, the battery light comes up, briefly, every time I start the car (and it’s a new battery), and the speedometer went crazy on one trip. All of this combined is wiring, and wiring seems to be beyond car repair people.

I save the longer trips for the weekend when I can drag my roommate, and my roommate’s car, about. His car isn’t possessed.

I rejoined the HTML WG. Again. The group has come up with a change procedure/process that I can support. There was confusion before about whether HTML WG members could issue formal objections, since supposedly we’re part of the group making the original decisions. The new procedure, though, reserves us the right to submit a Formal Objection if all other avenues are blocked. I’m more comfortable being part of the group, now. I even have a first change proposal assignment, due after the book deadline.

Good news from the group: the HTML+RDFa document is now a published draft. However, the work on distributed extensibility is slow going. It’s difficult to split off the technical concerns from the knee jerk reactions.

You may, or may not, have noticed that I don’t post links to my main feed, or this site, for my Just Shelley site. That site is very personal, and a lot of people who read my stuff are more interested in my more impersonal writings, such as tech. Of course, I haven’t been writing at any of my sites lately. Too busy with the book.

I did get a Wave invite–thanks to whoever sent me it. And yes, I’ve given out all of the Wave invitations I have.

What do I think of Google Wave? I think it’s too much for me, though I did have a fun exchange with Marius Coomans, as he was sailing the ideal waters around Australia. We exchange emails and twitter messages, but there’s something different about seeing a message being typed out by someone who is on a boat, and watching them make corrections, as they’re watching you correct your own mistakes. And you’re on opposite sides of the planet, and different hemispheres. It’s not earth shattering, but it is a bit uncanny.

So what else is there to say about Wave. The user interface sucks, but that’s not unusual for a Google application. The performance is sluggish, but it’s alpha. And it performs better than Twitter. Other than that, though, I’m just not sure about the usability of the service. I know that others like the tool, such as Laura Scott who had a nice write-up.

Frankly, though, I’m really getting burned out on the whole social media thing so I may not be a good judge.

There was another instance where I wrote one thing, and it was interpreted as the opposite. I supported what Kurt Cagle wrote on HTML5, but based on a intense Twitter exchange I had with another person, Kurt interpreted my reaction to be opposite of what it is.

Twitter is useless as a tool for doing more than pointing out a link or talking about what you had for breakfast.


HTML5, RDFa, and the Beatles

How is the ongoing debate about HTML5/Microdata and RDFa like a Beatles’ song? Read more at Bb RealTech: Maxwell’s Silver Hammer: RDFa and HTML5’s Microdata.

I’ve turned comments back on, at least until I get overrun by spam, or the crickets get too loud.


My HTML WG status

I posted about quitting the HTML WG on Twitter, but there’s only so much one can shove into 140 characters. Of course, I realize that most people will probably be uninterested in a longer writing on my reasons, but that’s the advantage of syndication feeds—you can see at a glance whether you want to read beyond the first few sentences of a writing. Or not.

First of all a clarification: I joined the HTML WG once. I quit the HTML WG once. I joined the HTML WG reluctantly, because as I wrote at the time, I’m really not a joiner. I feel I’m best writing in my own space, not participating in a back and forth in email lists; definitely not through quick non-thinking blurbs in an IRC channel, or teleconferences where key players never participate.

I did join, though, and became actively involved. However, I never could figure out the “rules” of the effort, and I found it both discouraging and exhausting. So much so that it drained the energy I needed for the writing I need to do for a living. More importantly, I felt I really wasn’t making a difference, and I’m not sure I was willing to play the game in order to make a difference.

A further point of clarification: My decision to quit did not come about because of any exchange I had yesterday with any person. It was a number of factors that led to my quitting, a primary one being the one I just mentioned, needing to focus on work. I’d already decided to quit before yesterday, but was waiting for a specific thread on RDFa to play out. I will mention, though, that some of the reasons why I’m leaving were echoed in that thread, including the hostility of the WhatWG backchannel IRC, and the lack of respect some members of this group have for members of the HTML WG and other W3C groups.

Some of the the WhatWG members seem to think that I’ve quit the HTML WG more than once, but they are mistaken. I unsubscribed from the WhatWG email lists, because I found the environment hostile. I stopped working on my assessment of metadata use cases, because the HTML5 author, Ian Hickson, suddenly released a new microdata section, changing everything I wanted to write.

I have unsubscribed from the WhatWG mailing list, and that won’t change. I have quit the HTML WG, and I may, but it’s unlikely, rejoin at some later time. But I have not stopped writing about the HTML5 specification. Whether I make a difference or not, my way of “participating”, in the HTML5 effort, and any other, is by writing in this space. And I will continue to do so, in my own time, and in my own way.


A Loose Set of Notes on RDFa, XHTML, and HTML5

There’s been a great deal of discussion about RDFa, HTML5, and microdata the last few days, on email lists and elsewhere. I wanted to write down notes of the discussions here, for future reference. Those working issues with RDFa in Drupal 7 should pay particular attention, but the material is relevant to anyone incorporating RDFa.

Shane McCarron released a proposal for RDFa in HTML4, which is based on creating a DTD that extends support for RDFa in HTML4. He does address some issues related to the differences in how certain data is handled in HTML4 and XHTML, but for the most part, his document refers processing issues to the original RDFaSyntax document.

Philip Taylor responded with some questions, specifically about how xml:lang is handled by HTML5 parsers, as compared to XML parsers. His second concern was how to handle XMLLiteral in HTML5, because the assumption is that RDFa extractors in JavaScript would be getting their data from the DOM, not processing the characters in the page.

“If the object of a triple would be an XMLLiteral, and the input to the processor is not well-formed [XML]” – I don’t understand what that means in an HTML context. Is it meant to mean something like “the bytes in the HTML file that correspond to the contents of the relevant element could be parsed as well-formed XML (modulo various namespace declaration issues)”? If so, that seems impossible to implement. The input to the RDFa processor will most likely be a DOM, possibly manipulated by the DOM APIs rather than coming straight from an HTML parser, so it may never have had a byte representation at all.

There’s a lively little sub-thread related to this one issue, but the one response I’ll focus on is Shane, who replied, RDFa does not pre-suppose a processing model in which there is a DOM. The issue of xml:lang is also still under discussion, but I want to move on to new issues.

While the discussion related to Shane’s document was ongoing, Philip released his own first look at RDFa in HTML5. Concern was immediately expressed about Philip’s copying of some of Shane’s material, in order to create a new processing rule section. The concern wasn’t because of any issue to do with copyright, but the problems that can occur when you have two sets of processing rules for the same data and the same underlying data model. No matter how careful you are, at some point the two are likely to diverge, and the underlying data model corrupted.

Rather than spend time on Philip’s specification directly at this time, I want to focus, instead, on a note he attached to the email entry providing the link to the spec proposal. In it he wrote:

There are several unresolved design issues (e.g. handling of case-sensitivity, use of xmlns:* vs other mechanisms that cause fewer problems, etc) – I haven’t intended to make any decisions on such issues, I’ve just attempted to define the behaviour with sufficient detail that it should make those issues visible.

More on case sensitivity in a moment.

Discussion started a little more slowly for Philip’s document, but is ongoing. In addition, both Philip and Manu Sporney released test suites. Philip’s is focused on highlighting problems when parsing RDFa in HTML as compared to XHTML; The one that Manu posted, created by Shane, focused on a basic set of test cases for RDFa, generally, but migrated into the RDFa in HTML4 document space.

Returning to Philip’s issue with case sensitivity, I took one of Shane’s RDFa in HTML test cases, and the rdfquery JavaScript from Philip’s test suit, and created pages demonstrating the case sensitivity issue. One such is the following:

<title>Test 0011</title>
<div about="">
Author: <span property="dc:creator t:apple T:banana">Albert Einstein</span>
<h2 property="dc:title">E = mc<sup>2</sup>: The Most Urgent Problem of Our Time</h2>

Notice the two namespace declarations, one for “t” and one for “T”. Both are used to provide properties for the object being described in the document: t:apple and T:banana. Parsing the document with a RDFa application that applies XML rules, treats the namespaces, “t” and “T” as two different namespaces. It has no problem with the RDFa annotation.

However, using the rdfquery JavaScript library, which treats “t” and “T” the same because of HTML case insensitivity, an exception results: Malformed CURIE: No namespace binding for T in CURIE T:banana. Stripping away the RDFa aspects, and focusing on the namespaces, you can see how browsers handle namespace case in an HTML document and in a document served up as XHTML. To make matter more interesting, check out the two pages using Opera 10, Firefox 3.5, and the latest Safari. Opera preserves the case, while both Safari and Firefox lowercase the prefix. Even within the HTML world, the browsers handle namespace case in HTML differently. However, all handle the prefixes the same, and correctly in XHTML. So does the rdfquery JavaScript library, as this test page demonstrates.

Returning to the discussion, there is some back and forth on how to handle case sensitivity issues related to HTML, with suggestions varying as widely as: tossing the RDFa in XHTML spec out and creating a new onetossing RDFa out in favor of Microdatacreating a best practices document that details the problem and provides appropriate warnings; creating a new RDFa in HTML document (or modifying existing profile document) specifying that all conforming applications must treat prefix names as case insensitive in HTML, (possibly cross-referencing the RDFa in XHTML document, which allows case sensitive prefixes). I am not in favor of the first two options. I do favor the latter two options, though I think the best practices document should strongly recommend using lowercase prefix names, and definitely not using two prefixes that differ only by case. During the discussion, a new conforming RDFa test case was proposed that tests based on case. This has now started its own discussion.

I think the problem of case and namespace prefixes (not to mention xmlns as compared to XMLNS) is very much an edge issue, not a show stopper. However, until a solution is formalized, be aware that xmlns prefix case is handled differently in XHTML and HTML. Since all things are equal, consider using lowercase prefixes, only, when embedding RDFa (or any other namespace-based functionality). In addition, do not use XMLNS. Ever. If not for yourself, do it for the kittens.

Speaking of RDFa in HTML issues, there is now a new RDFa in HTML issues wiki page. Knock yourselves out.

updatenew version of the RDFa in HTML4 profile has been released. It addresses a some of the concerns expressed earlier, including the issue of case and XMLLiteral. Though HTML5 doesn’t support DTDs, as HTML4 does, the conformance rules should still be good for HTML5.

RDF Semantics

Wolfram Alpha: What is RDF?

I asked Wolfram Alpha: what is RDF?

results asking Wolfram Alpha what is rdf

I would have been more impressed by Wolfram Alpha if at the end of its interpretation of my request, it asked me, “Was this answer correct? Was this answer complete? If not correct or complete, what do you consider RDF to be?”

I then asked the same question of Google.

Google: what is RDF