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Re: long-range datatyping and rdfa/microdata

From: Steve Harris <steve.harris@garlik.com>
Date: Fri, 10 Jun 2011 12:58:17 +0100
Cc: Richard Cyganiak <richard@cyganiak.de>, RDF WG <public-rdf-wg@w3.org>
Message-Id: <155293AD-E966-41F5-B1F5-FAEE337822E9@garlik.com>
To: Dan Brickley <danbri@danbri.org>
On 2011-06-09, at 10:11, Dan Brickley wrote:

> On 9 June 2011 10:49, Richard Cyganiak <richard@cyganiak.de> wrote:
>> Dan,
>> On 8 Jun 2011, at 17:02, Dan Brickley wrote:
>>> This can be used in RDFa as so: <p>blah blah <span
>>> property="foaf:age">39</span> blah</p>.
>>> If we try to persuade publishers to put datatype="xsd:integer"
>>> alongside each age, ... we'll have a hard time. So is there anything
>>> we can do at the schema level?  Mumble mumble range mumble...
>> I see this mostly as a syntax problem, not a schema problem.
> I'm sympathetic to that.
>> Realistically, I think the correct answer is to bury RDF's datatypes under a mountain of syntactic sugar. Turtle does this quite a bit and it works well. With JSON we can do it to the same degree. RDFa didn't attempt it, but rather tried to align the surface syntax closely with the abstract syntax, which I think in hindsight (20/20 etc) was a lost opportunity.
>> Speaking of microdata. They said: “Forget prefix mappings, we'll just use short URIs.” That's a winning formula. Two years from now, the rdf:, rdfs:, and xsd: namespace URIs with all that clutter inside will feel like they were designed by a deranged madman. We should pave the road so that a future WG can unify them as something like <http://w3.org/ns/rdf#> or even <http://rdf.w3.org/>.
> And to that.
>> To recap, if someone wants to state their age in RDFa, it is:
>>     ...
>>     prefix="foaf: http://xmlns.com/foaf/0.1/ xsd: http://www.w3.org/2001/XMLSchema#"
>>     ...
>>     <span property="foaf:age" datatype="xsd:integer">39</span>
>> But if the RDFa syntax had turned out a bit differently, and the FOAF project had chosen a different namespace URI, it could well have been (in HTML+RDFa):
>>     <span integer property=http://foaf.org/age>39</span>
> The foaf.org domain was gone by the time we started using the name.
> Regarding the '/foaf/0.1/', ... hindsight is a wonderful thing.
> Success snuck up on us slowly and there never felt like a 'right time'
> to switch.
> First rule of namespace URI design "you're more likely to regret
> things you included, than things you omitted".
> I do have 'foaf.tv' though, which is even shorter. It isn't being used
> for much that can't be moved.
>> Or perhaps the RDFa WG and the FOAF project can still make it so. At any rate, it doesn't look like a model problem to me.
> Well foaf:age does not currently have a datatype set, for the
> verbosity reasons you give. Perhaps datatype annotations can be added
> into RDFa 1.1 profiles?

Honestly I'm not convinced that the datatyping matters in this kind of situation, if someone says their age is "39"^^xsd:string, so what. The FOAF world (as will be any schema where the data is so widely used) is full of nonsense like foaf:age "twelve", foaf:age "79b8c9c56b0b879941b3cd424b1af2bc", foaf:age "三十九"@zh and so on, the fact that some of them aren't tagged as xsd:integers doesn't even register on the scale of the kind of nastiness you have to cope with.

If you're trying to calculate the average age of people interested in frogs, then you just have to ignore anything that doesn't cast cleanly to an integer.

- Steve

Steve Harris, CTO, Garlik Limited
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Received on Friday, 10 June 2011 11:58:50 UTC

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