RDF, again

Paul Prescod paul at prescod.net
Tue Nov 23 16:12:29 GMT 1999


> > Without the minimization hacks, the syntax is verbose and hard to
> > read.
> 
> That's inevitable for any kind of object exchange, though -- it's the
> nature of the normalized object-oriented information.
> 
> Here's some mostly non-minimized RDF (using only the rdf:type as class
> name):

The thing I find confusing about the RDF syntax is that the element type
name can be either an RDF type name or an RDF property. XML makes no
distinction and that's why I think that it is difficult to use for
object oriented interchange. Your example doesn't run into that problem
really because it only goes one level deep. But what does the RDF for
this CSS-style object representation look like:

person{
	name: person-name{ first: "Paul"; last: "Prescod"};
	address: snail-mail-address{
		street: street-address{
			number: 5936; 
			street: "Lovers Lane"
		city: city( #!Dallas );
		state: state( #!Texas )};
	siblings: #sibling1 #sibling2 #sibling3}

(curly braces for structures, parentheses for primitive types,
concatenation for lists, semicolons for property separators)

<ramble>
Note also that common XML usage puts datatypes in the schema or
elsewhere. To recognize an integer as such you need the schema or some
other external knowledge. Some DTDs have <int> elements but that's so
ugly that it hasn't really "caught on." The XML world is very
inconsistent in its thought about the appropriateness of dependence on
the schema. I think that that dependence is slowly creeping back into
vogue.

Speaking on behalf of the devil, I'd say that in one week we could
define (or just find) an S-expression-like language with none of these
weaknesses and in less time we could write a parser for it. It could
have "XML element" as a primary data type for embedded XML and could
also be embedded IN XML.

I am enough of a language aficionado to feel that there is virtue in
having languages that are immediately interpretable. Languages where the
semantics "fall out" visually. But I know you are a Perl programmer so I
won't ask you to agree.

The fashionable thing is to say that these are problems that can be
hidden "behind a good GUI" but here we are, (more than?) twenty years
into the Age of Emacs and the best IDEs are still designed to help us
type text faster. Unless we are going to standardize graphical
representations of RDF graphs, and send those representations through
email, and embed RDF renderers and editors in every device, people will
still look at the text.
</ramble>

-- 
 Paul Prescod  - ISOGEN Consulting Engineer speaking for himself
It's such a 
Bore
Being always
Poor
LANGSTON HUGHES
http://www.northshore.net/homepages/hope/engHughes.html



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