[SCL] Re: some explanation

[John F. Sowa]

Ed,

Thanks for the comments.  I basically agree.

And while we're talking about translating logic
to XML form, I would like to quote a passage
by Tim Bray, one of the chief developers and
proponents of XML who also wrote one of the
early tutorials on RDF back in 1998.

Although Tim strongly supports XML, he is decidedly
lukewarm about RDF syntax, and I strongly agree
with him.  As I said before, there are many good
applications for XML, but please note what Tim has
to say at the end of the excerpt below:

    Speaking only for myself, I have never actually
    managed to write down a chunk of RDF/XML correctly,
    even when I had the triples laid out quite clearly
    in my head. Furthermore -- once again speaking for
    myself -- I find most existing RDF/XML entirely
    unreadable. And I think I understand the theory
    reasonably well.

If Tim Bray says that the RDF designers should go
back to the drawing board, I don't believe that we
should consider it as an ideal syntax for logic.

John
______________________________________________________

Source: http://www.tbray.org/ongoing/When/200x/2003/05/21/RDFNet

The Problems with RDF

RDF is well into middle age as standards go, and it hasn't exactly 
turned the world inside out. This despite fierce backing from Tim 
Berners-Lee, who sees RDF as a key foundation component for the Semantic 
Web. In fact, as far as I know I've never used an RDF application, nor 
do I know of any that make me want to use them. So what's wrong with 
this picture?

I have spent time as a fairly militant soldier in the RDF ranks, as 
witness the XML.com article above, and my quixotic effort 
single-handedly to browbeat IBM and Microsoft into turning XML Schemas 
into an application of RDF. But I'm too tired now, and I find that I 
like RDF-the-idea a whole lot better than RDF the actual technology. In 
particular, I have little sympathy with the effort to RDFify RSS. The 
RDF version is harder to read, harder to write, and doesn't offer enough 
payback to make this worthwhile.

How to Fix It

RDF has ignored what I consider to be the central lesson of the World 
Wide Web, the “View Source” lesson. The way the Web grew was, somebody 
pointed their browser at a URI, were impressed by what they saw, 
wondered “How'd they do that?”, hit View Source, and figured it out by 
trial and error.

This hasn't happened and can't happen with RDF, for two reasons. First 
of all, the killer app that would make you want to View Source hasn't 
arrived. Second, if it had, nobody could possibly figure out what the 
source was trying to tell them. I don't know how to fix the 
no-killer-apps problem, but I'm pretty sure it's not worth trying until 
we fix the uglified-syntax problem.

It's the Syntax, Stupid!

Conceptually, nothing could be simpler than RDF. You have Resources, 
which by definition are identified by URIs. The resources have 
Properties, which by convention are identified by URIs. The properties 
have Values, which can be strings or numbers or Resources.

Everything's a triple: (Resource, Property, Value). Not only is this 
easy to understand, but it's easy to mash into an RDBMS, and easy to 
optimize that RDBMS schema after a little analysis of the data.

Given all this excellent simplicity, you have to kind of boggle when you 
look at one of the first examples taken from a recent RDF Working Draft.

<rdf:Description rdf:about="http://www.w3.org/TR/rdf-syntax-grammar">
   <ex:editor>
     <rdf:Description>
       <ex:homePage>
         <rdf:Description rdf:about="http://purl.org/net/dajobe/">
         </rdf:Description>
       </ex:homePage>
     </rdf:Description>
   </ex:editor>
</rdf:Description>

Where, pray tell, are the resources, properties, and values? What 
benefit could I expect to derive from viewing this particular source?

Speaking only for myself, I have never actually managed to write down a 
chunk of RDF/XML correctly, even when I had the triples laid out quite 
clearly in my head. Furthermore—once again speaking for myself—I find 
most existing RDF/XML entirely unreadable. And I think I understand the 
theory reasonably well.