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Re: Publish RDF Concepts as revised WD? (was: Re: Agenda 16 May telecon)

From: Steve Harris <steve.harris@garlik.com>
Date: Thu, 17 May 2012 15:45:37 +0100
Cc: Richard Cyganiak <richard@cyganiak.de>, Guus Schreiber <guus.schreiber@vu.nl>, RDF WG <public-rdf-wg@w3.org>
Message-Id: <EC5F1E07-B329-4153-A194-A79AB8A3F173@garlik.com>
To: Ivan Herman <ivan@w3.org>
On 2012-05-16, at 16:18, Ivan Herman wrote:
> 
> On May 16, 2012, at 14:17 , Steve Harris wrote:
>>> 
>>> Regarding ISSUE-63, HTML datatype: I think this is a Good Thing and will be popular. The most contentious point is the definition of the value space. It appears complex (DOM DocumentFragment nodes), but in reality it makes implementation of conforming parser *simpler* because it allows them to produce any of a number of equivalent results. The complexity only affects systems that decide to implement value-based comparison for HTML literals, something that is entirely optional. I expect few or no systems to do it.
>> 
>> I see limited utility in being able to do = comparisons on non-lexically identical HTML5 fragments. But I may well be missing some important usecases.
> 
> If I look at
> 
> http://lists.w3.org/Archives/Public/public-rdf-comments/2012Apr/0000.html
> 
> the attributes added to an HTML Literal have a 'semantic' role (controlling translations, for example) and these may result in an RDF graph (eg, via RDFa). Interaction with the user, running beautifying tools, etc, may change the Literal fragments without changing the intended semantics (ie, by retabulating the fragment to make it pretty...). Having a clear way on comparing the literals without just lexically comparing them looks really important.
> 
> I realize this is a bit vague, but the point is that the definition makes HTML Literals more robust against non-essential changes when combined with RDFa.

Yeah, so that bit I get, but I just can't ground it in a concrete use-case.

I can imagine for e.g. a CMS wanting to use RDF for storage, but then non-lexical comparison isn't important.

There is an interoperability cost to specifying a complex value-space comparison, so I don't think we should take the decision lightly. OTOH if there's a really good use-case for non-lexical comparison, it would be annoying to have specified a lexical comparison.

In my opinion, we as a community have a very bad track record* in making these decisions the right way first time - and we tend to go for the more complex wrong options, rather than the simpler wrong options, in my opinion.

* bNodes, XMLLiteral, rdf:List, containers, reification, plain literals,  I'll stop before I get more controversial :)

- Steve

-- 
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Received on Thursday, 17 May 2012 14:46:11 GMT

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