Re: GRDDL and OWL/XML

Murray Maloney wrote:
>
> For the record, I disagree with the position being put forward
> by Harry Halpin as chair of the former GRDDL WG.
>
> =============================
>
> On point #1, while it may not be the deployment strategy that Harry 
> and others favor,
> I acknowledge Bijan Parsia's interpretation of the GRDDL specification.
>
> To wit, the target of a grddl:transformation link may be anything that 
> yields
> a GRDDL result from a corresponding resource:
>
> "If an information resource([WEBARCH], section 2.2) IR is represented 
> by an XML document with an XPath root node R, and R has a GRDDL 
> transformation with a transformation property TP, and TP applied to R 
> gives an RDF Graph[RDFC04] G, then G is a GRDDL result of IR."
>
> The onus would be on Bijan and others to demonstrate that the 
> OWL-->RDF mapping
> spec is sufficient to yield a faithful RDF graph. That might require 
> an existence proof.
>
> It should be noted that pointing to an XSL transformation is not 
> equivalent to
> pointing to an executable. An XSL transformation is opaque to anyone 
> without
> an XSLT processor of the appropriate version.
>
> =============================
>
> On point #2, Harry claims:
>
> "The advantage of having a GRDDL from OWL 2 to RDF is that it is to a 
> larger audience (RDF users without an explicit OWL 2 to RDF 
> transform), who might otherwise be unable to have what benefits OWL 2. 
> in RDF, can have these benefits with a minimal of work."
>
> To paraphrase: "The advantage to using A is that you don't have to use 
> B."
>
> Please explain how it could be better to use an ad-hoc transformation 
> of OWL-->RDF
> over the specification that has been explicitly designed to perform 
> that function.
>
> An XSL transformation requires an XSLT processor.
> An OWL-->RDF mapping requires an OWL-->RDF processor.
>
> Without claiming that XSLT is superior in any fashion, please explain
> logically how you can argue that an XSL transform is REQUIRED in any way.
>
> =============================
>
> On point #3: GRDDL discusses the ramifications of having a popular 
> transform.
> Designers of GRDDL-aware and OWL-aware processors should be encouraged
> to build in transformations for common document classes.
>
>
Murray,

    Quick note - I did not say that XSLT was required as a language, as 
the GRDDL spec clearly defines that any transformation language will do 
that fulfills the spec, i.e. as you put it "gives an RDF graph."

    And if an XSLT is used, it should be of course conformant, i.e. not 
ad-hoc and fulfill the specification as well as any test cases.

    And as DanC pointed out, the reason we *recommend* but do not 
*require* XSLT is in the GRDDL Spec:

"Developers of transformations should make available representations in 
widely-supported formats. XSLT version 1[XSLT1] is the format most 
widely supported by GRDDL-aware agents as of this writing, though though 
XSLT2[XSLT2] deployment is increasing. While technically Javascript, C, 
or virtually any other programming language may be used to express 
transformations for GRDDL, XSLT is specifically designed to express XML 
to XML transformations and has some good safety characteristics; XQuery 
has similar characteristics to XSLT, though use of XQuery in GRDDL 
implementation is less widely deployed at the time of this writing."

       thanks,

          harry

Received on Wednesday, 21 May 2008 19:37:34 UTC