W3C home > Mailing lists > Public > public-rdf-comments@w3.org > August 2012

Re: Inverse properties in Turtle

From: Steve Harris <steve.harris@garlik.com>
Date: Sat, 11 Aug 2012 19:40:27 +0100
Cc: Andy Seaborne <andy.seaborne@epimorphics.com>, public-rdf-comments@w3.org
Message-Id: <EE2AE036-113F-4981-8C4B-74BF824B641C@garlik.com>
To: Pat Hayes <phayes@ihmc.us>
On 11 Aug 2012, at 18:02, Pat Hayes wrote:

> On Aug 11, 2012, at 5:22 AM, Andy Seaborne wrote:
>> Hi Dan,
>> On 11/08/12 07:46, Dan Brickley wrote:
>>> Hi Dave,
>>> On 10 August 2012 19:25, Dave Beckett <dave@dajobe.org> wrote:
>>>> Dear RDF Working Group
>>> (Just a personal response here)
>> Ditto.
>>> Agreed. This is a niche topic, but I still now thing it is of occasional use.
>>> In particular, as a maintainer/editor/contributor for popular RDF
>>> vocabularies (FOAF, schema.org and others) I believe there is implicit
>>> demand for this which is often expressed instead in terms of requests
>>> for new inversely named properties. Whenever someone asks a vocabulary
>>> maintainer to add 'isDirectorOf' alongside 'director', or asks what
>>> the inverse of 'actor', or 'associatedAnatomy' or 'depicts' is, they
>>> are talking about just this issue.
>> For those people, do you think "^" will read acceptable to those people?  (Your point about "isXof" not always being the best choice of name is also interesting.)
>>>> 3. It is not in SPARQL's data syntax.
>>>> 4. There is a high bar to add a new feature to an existing, well
>>>>   understood and implemented language like Turtle.  This feature does not
>>>>   fit that in my judgement.
>>> Taking those two together, ...
>>> I only support adding such a construct if it has a comparable notation
>>> in SPARQL. They might not be 100% identical, but the basic concept
>>> ought to either be in both, or in neither. Turtle and SPARQL share a
>>> common heritage in N3; if we can make teaching them (Turtle and
>>> SPARQL; I consider N3 something like a "Labs project") easier by
>>> sharing structure and ideas, we ought to.
>> A difference between "^:directory" (or the "is...of" syntax) and a property :isDirectorOf is that the "^" solution immediately does the reversing of the written subject and written object.
>> :Ridley_Scott ^:director :Blade_Runner
>> leading to a possible unexpected situation later:
> POSSIBLY unexpected. If someone were under the illusion that the caret syntax created a new property, they would be surprised or disappointed at this point. The answer, surely, is to take pains, in writing the documentatio, to explain carefully that it does not do this. Your example would be a good one to use is such a tutorial, for example. But the fact that a feature MIGHT be surprising to someone who DIDNT read the tutiorials and does not understand it, it surely not a good argument for not including it. 

If someone were of that illusion, or if they simply missed it lexically, or didn't know what it means.

Regardless, this will make Turtle harder to teach. I don't have a feeling for how much harder.

- Steve 

Steve Harris, CTO
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Received on Saturday, 11 August 2012 18:40:56 UTC

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