Re: Not GRDDL, but GRDDL-like (was Re: GRDDL and OWL/XML)

On 20 May 2008, at 00:37, Harry Halpin wrote:

>
> Bijan Parsia wrote:
>>
>> On 13 May 2008, at 15:56, Chimezie Ogbuji wrote:
>>
> [snip]
>> I believe that everyone else agrees that the GRDDL spec does *not*  
>> require an executable, downloadable specification of the  
>> transformation at the namespace document.
> That's a bit strong.

Is it?

> I think agreement of most of the remaining active members (at least  
> myself, Chime, David Booth, not sure about DanC and Jeremy) of the  
> GRDDL WG is that executable code, in particular XSLT, would be useful,

That says nothing about spec conformance. I stand by my assertion  
(which Dan agrees with) that the spec does not require an executable.

> and there is no obvious use value in a non-executable version.

I think I've provided lots of use value scenarios, but ok.

> Linking to a list of implementations from the namespace document  
> using RDDL would be useful though. And having links to multiple  
> types of transforms (distinguished by media types as mentioned by  
> Norman Gray) could be useful as well. What is the use-case of a non- 
> executable GRDDL transformaton?

To spec what a GRDDL agent should do when encountering that  
namespace. In the OWL case, of course, it was already obvious, but in  
other cases it may not be.

>> Looking at that text, it seems that if we apply your hermenutical  
>> strategy we'd also end up with XSLT required ("XSLT result tree"),  
>> however, it seems your view is not demanded even by that snippet.  
>> We can easily speak of a non-computable function "being applied"  
>> in various mathematical contexts. Also, the prior text makes clear  
>> that this is a "should":
>>
>> """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."""
>>
>> So, I believe that my preferred strategy is supported by the spec  
>> and is GRDDL, not merely GRDDLesque.
>
> I could implemented an OWL-reasoner by writing it down an algorithm  
> and then publishing it in HTML,

?

> would this count as an implementation? I think the answer would  
> tend to be "no."

I thought the GRDDL implementation was, y'know, the GRDDL agent. I'm   
not suggesting that people download non-executable GRDDL agents.

> Generally, if you were selling someone an OWL 2 reasoner, they  
> would expect code, no? Same with GRDDL.

What's "GRDDL"? I mean, without a qualifier. I expect a GRDDL agent  
to be implemented and to implement various transformations.

>> This is an important point to me since various pro-GRDDL people in  
>> the WG have argued that without an executable we have failed  
>> according to the spec and thus failed our charter requirements. I  
>> only endorsed the charter (and encouraged others to so endorse)  
>> with the (weak) GRDDL requirement because I read the above spec  
>> text and came to, what seems to me, an obvious conclusion.
>
> I think people have argued clearly that an executable one could be  
> useful for RDF-consuming GRDDL-enabled agents that would like to  
> "glean" some information from OWL 2.

*An* executable, not a silently auto-downloadable one.

> That's a use-case that I have yet to see an argument against that  
> caching and warnings about normativity would not address.

That's not a use case, that's a deployment scenario. You start with  
the presumption that GRDDL-enabled agents will not bundle transforms.

After all, they don't need to *DO* the coding themselves! Someone can  
write a free XSLT transform and the GRDDL agent author can download it.

>> From a marketing perspective, it feels like a bait and switch. I  
>> feel like I did due diligence and now am sandbagged. Proper specs  
>> *cannot* require people to interview members of the community to  
>> determine what conforming behavior is. That defeats the point!
> No-one else in the community has ever brought up the point that the  
> GRDDL transformation could be non-executable.

This is a weakness on your part, not a strength. It's a  
straightforward reading of the spec.

Part of the point of specs is to codify *in the spec* the understanding.

One thing I'm trying to convey is that I thought I *was* part of the  
GRDDL community, broadly construed. But I guess I'm not and people  
with my sorts of concerns and perspectives are not. (That's fine!  
Nothing morally wrong with that. Just be aware that it limits adoption.)

> Thus, I think your reading of the specification is unique. I am  
> glad you have brought this up, as no-one has thought this through  
> before, and it is an intelligent if unusual point.
>
> I think if you or others do not want an executable GRDDL  
> transformation, or object to a RDF translation of OWL2/XML to RDF,  
> that's fine. It is clear you believe an executable GRDDL is  
> unnecessary or harmful and there is no reason to address RDF- 
> consuming agents that may not have OWL2XML local transforms. I  
> would be interested if other members of the OWL2 WG also think this  
> is the case.

Some do, some do not. I'm still unclear why this is a *use* case.

Cheers,
Bijan.

Received on Tuesday, 20 May 2008 11:35:01 UTC