Re: GRDDL and OWL/XML

>> How is use of XSLT an anti-pattern?
> 
> So, first, let me emphasize that I say this very specifically for the
> situation of OWL/XML and (I suspect) POWDER. And I really mean that I
> think it's, by strong default, wrong for a W3C working group to
> provide as a normative or informative deliverable a namespace
> document which points to an XSLT *or any other implementation of a
> GRDDL transformation function* in such a way that GRDDL processors
> will, automatically, use that implementation. This is an overridable
> default, but a strong default, IMHO.
> 
> I feel fine in asking a W3C wg to provide a specification *for the
> transformation function*, but it should not be the presumption that
> saying "Support GRDDL" means providing an implementation.

I'll leave the compliance criteria to others, but I think that an informal
description of a transformation function is much better than none, with an
actual reproducible description (i.e. An XSLT document for instance) being
the best case scenario.  But saying it is *wrong* for a working group to
provide a 'live' transformation function is a bit strong especially since
these are all semantic web activities and thus it is natural for them to
facilitate automatic consumption by agent by providing such material.
 
> I will argue both against the doing and the presumption.
> First against the presumption: The GRDDL spec, afaict, requires
> nothing more that the specification of a transformation function and
> an identifier for it. That is how I read the spec and, during the OWL
> WG charter debates, how I represented the requirement for "GRDDL
> support". There's a big difference between requiring a spec for a
> transformation and requiring an implementation thereof.

Certainly.  But, intuitively, given the nature of GRDDL, the specification
of a transformation from an OWL/XML document to an RDF abstract syntax is
more a modeling exercise than anything else (the status quo XML
transformation function specification language is very declarative). I would
imagine prior effort in mappings to the OWL abstract syntax would be very
re-usable for this purpose.  So, I agree there is a difference, but I don't
think it is as large as you characterize it.

> I believe  
> other people outside the GRDDL community can feel like they were
> shanghaied into something they really didn't expect to have to do.
> This means that the reflex will be to resist any GRDDL requirements
> or requests altogether (which is certainly where I'm leaning now).
> So, just tactically, I recommend allowing and encouraging the lighter
> path. My understanding of the spirit of GRDDL was *not* to be
> intrusive. Requiring people to produce, or even to bless, an
> implementation is rather intrusive.

Well, it is not so intrusive if the idea is to facilitate automated
interaction with sources of "GRDDLable" content (in this case, web-based
OWL content).  I guess it might help if I had a better understanding of the
GRDDL/OWL usecase here.  Is it being used only as a mechanism for a
particular XML-based concrete syntax for OWL or is there more to it?
  
> Against the implementation requirement.
> 
> 1) The primary purpose of W3C working group is to produce
> specifictations...standards, in fact. Many members of the W3C (who
> pay fees, after all) are implementors and vendors of implementations.
> The W3C, itself, enjoys a great deal of prestige and attention that
> its smaller members cannot hope to compete with. Futhermore, the W3C
> has a monopoly of W3C web space. Thus, it has a monopoly on what
> implementations it not just recommends, but *delivers* to people (via
> GRDDL agents). This makes it very difficult to compete with that
> implementation. Since WGs generally don't live very long, things
> stagnate (i.e., the W3C doesn't generally have the resources to
> maintain *lots* of software).

I'm not sure I understand where competition comes into play in this
conversation.
   
> I don't think it's a real burden on GRDDL implementors to find or
> write a translation implementation from OWL/XML to OWL/RDF. If
> someone provided a production quality XSLT, the GRDDL implementors
> could just download it and bundle it. Indeed, I would hope that
> quality GRDDL implementation would allow users to configure their
> client for offline or variant use (e.g., using XML Catalog).

Agreed.
 
> There is a strong, large, and vocal community which is against
> putting key parts of implementations of global consensus specs on the
> web with the intention that it be downloaded and used by
> implementations. (I'm clearly a member of that community :)) Here is
> one explication of this line:
> http://hsivonen.iki.fi/no-dtd/
> Everything there applies to GRDDL XSLT (or other implemention).
> 
> 3) When you have a normative spec for a transformation function (as
> OWL does), adding an XSLT sets up a 'second variant' of the spec (as
> well as being a blessed implementation) and one that gets directly
> used in spite of it being nominally informative. This is a violation
> of DRY (don't repeat yourself) and divides attention from verifying
> the actual spec (e.g., with multiple implementations). Worse, bugs in
> the program become part of the de facto spec.

Hmm.. If the XSLT 'set up' is a correct implementation of the normative spec
(as a transformation function) how would it be a 'second variant'? I don't
see how use of a live (re-usable) transformation function is a violation of
DRY.   Implementations will apply the transformation function in a manner
compliant with the normative definition, so it actually speaks to the value
of DRY: The XSLT document is placed in one place as an instance of the
normative specification for the syntax and thus ensures proper use each
time.

It seems to me that, having a testable-reusable XSLT implementation of the
normative specification (especially one as wide spread as OWL) of a syntax
guarantees a high-level of quality assurance in implementations.
 
-- Chimezie


===================================

P Please consider the environment before printing this e-mail

Cleveland Clinic is ranked one of the top hospitals
in America by U.S. News & World Report (2007).  
Visit us online at http://www.clevelandclinic.org for
a complete listing of our services, staff and
locations.


Confidentiality Note:  This message is intended for use
only by the individual or entity to which it is addressed
and may contain information that is privileged,
confidential, and exempt from disclosure under applicable
law.  If the reader of this message is not the intended
recipient or the employee or agent responsible for
delivering the message to the intended recipient, you are
hereby notified that any dissemination, distribution or
copying of this communication is strictly prohibited.  If
you have received this communication in error,  please
contact the sender immediately and destroy the material in
its entirety, whether electronic or hard copy.  Thank you.

Received on Saturday, 10 May 2008 01:36:22 UTC