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RDF: syntax refuted?

As expected, the RDF syntax permatthread does the rounds

Ian Davis:

It's essential that the model is watertight before we can do anything major with the serialization syntax.

Yet the XML was heavily reworked while the Model Theory was invented from scratch. And n-triples was invented at the same time. No such ordering is essential or neccessary (but take a look at what Ian's doing with the XML). On the other hand, such Models are never watertight - just consistent.

Danny Ayers:

The web might have got to where it is today through being a collection of syntaxes, but for it to progress any further I think we need to step up a layer of abstraction. So I don't think we need to worry too much about Tim's syntax-oriented criticism.

Yes, RDF is not XML (as usual I put that in red, so no-one will miss). That's not sufficient to excuse an ugly hard to use serialization. And don't even start me on depending on tools...

Shelly Powers:

We need to stop treating RDF/XML as yet another variation of tags similiar to HTML and start looking at it as a form of virtual binary code -- machine generated and consumed, but output in plain text. Until we do, we'll never get to the point of creating that killer app that Tim wants.

Well following this argument to its conclusion there's no point using a text format in the first place, so whatever way you cut it the XML needs to be sorted out. Text vesus binary is a whole other permathread, but in my humble but correct opinion, the 'it's just for machines' argument doesn't fly on the Internet, never has, never will. The syntax matters - it forces you to think.

Dave Beckett:

The title of the document is RDF/XML Syntax Specification (Revised) and Revised is important. It is, hopefully, a better description of an existing syntax, which Tim Bray was involved in designing. Not me.

We removed some things, added others, but didn't rewrite the core language with all it's many abbreviations - that would break the contract with the existing deployed users of RDF/XML who have put it in their products

In my experience, Dave Beckett has the patience of a saint. He also has (or had) the toughest editorial job at the W3C for well over a year. But this is a tired excuse. If we look at the original charter it says the wg will not develop a new RDF syntax or new RDF model. Which turned out to be bunk - the Model Theory was developed from the ground up and it is, without question, a new model. Make no mistake, the RDF MT is a deviation from the charter that took up a large proportion of the wg's time during 2001 and the first half of 2002. This was or is, hardly ever questioned - but that is so much the worse for the charter since the model needed serious work. On the other hand the suggestion that the XML be developed from the ground up was and is consistently argued against by pointing to the charter, but it needed no less rework. It's important to be consistent about these things. And I'm mystified as to how a new RDF semantics does not break the contract with the existing deployed users of RDF/XML, but a new syntax does. - perhaps it's because most people with RDF data aren't operating over it yet at the level implied by the model theory.

I mean come on, how hard can this be? It would be worth knocking up a pretty XML syntax to just to prove Tim Bray, Sean McGrath and I wrong :)


May 25, 2003 04:06 PM

Comments

Danny
(May 25, 2003 05:12 PM #)

Thanks for quoting one of my better statements ;-)

For there to be a change of syntax to be justified, there would need to be pretty major improvements (and that's apart from the politics needed to get something through the W3C).
Given the graph/tree mismatch I'm not sure this is even possible - personally I thought Tim Bray's RPV syntax was actually uglier than abbreviated syntax RDF/XML. If all you want is human-readable, Notation3's not bad, it's just not XML.

I'd also question how important readability is for any data-oriented XML. RDF isn't XML but (early) HTML isn't XML either. Once the generators/parsers or whatever are set up, there shouldn't be much need to go poking around. In the case of RDF/XML, it may not be that simple, but I think there's enough legibility for maintenance purposes.

I do think there's a bit of exagerration going on too - it may not be optimum, but RDF/XML syntax isn't harder to work with than say XHTML(+CSS) or XSLT.

Overall I just reckon effort will be better used at this point in time working on getting some good tools together, rather than worrying about the inelegance of RDF/XML syntax. If someone does come up with a neat XML syntax, great, if not, no big deal, adoption of RDF will just be a little slower.

Danny
(May 25, 2003 05:16 PM #)

D'oh, you got in that last paragraph while I was typing...
I don't think the MT's actually that far from the original intention, just filled out more - the fact that it hasn't broken usage should suggest that.
It's a shame it wasn't in the charter to rebuild the syntax, but I do think the work that they have done was worthwhile.

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