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

Re: [TURTLE] Turtle Inverse Properties

From: Lee Feigenbaum <lee@thefigtrees.net>
Date: Sat, 18 Aug 2012 22:53:44 -0400
Message-ID: <50305538.2060104@thefigtrees.net>
To: David Booth <david@dbooth.org>
CC: Gavin Carothers <gavin@carothers.name>, RDF-WG WG <public-rdf-wg@w3.org>, public-rdf-comments@w3.org, Tim Berners-Lee <timbl@w3.org>
On 8/17/2012 3:58 PM, David Booth wrote:
> On Fri, 2012-08-17 at 11:30 -0700, Gavin Carothers wrote:
> [ . . . ]
>> Objections to both original syntax and revised syntax
>> =====================================================
>> Turtle is a reasonably settled languages, changes made by the working
>> group so far have been limited to areas of existing differences in
>> implementation.
>> No demand over years of implementation experience
> I think that may be slightly misleading, because Turtle was not
> previously standardized, and hence was on the same footing as N3, and
> those who wanted to use this feature simply considered their RDF to be
> N3 instead of Turtle.  I.e., there was no *need* to demand it in Turtle
> because Turtle was not previously chosen over N3 for standardization.

In turn, I think this is misleading -- Turtle has far more 
implementations than N3, and so -- standard or not -- has had far more 
opportunity for users of those implementations (of which there are many) 
to demand this feature in a volume that would have lead to it being 
adopted. This has not happened even a single time that I know of. Given 
the scarcity of N3 implementations, I sincerely doubt that users simply 
abandoned their existing Turtle toolkits and picked up an N3 toolkit 
instead so that they could use inverse property syntax.

I haven't weighed in on the discussion before, so I'll give my feeling 
here. I'm not motivated by the use cases for this feature, and I think 
that the costs (as enumerated by Gavin and others) are way too high to 
change Turtle in this way. I support not adding inverse property syntax 
to Turtle.


> [ . . . ]
>> 2. Add ^ property path syntax to Turtle.
> +1.  I like it a lot.  Conciseness improves clarity, which reduces
> errors.
>>      1.1. Allowing "literals" in any subject position by syntax,
>> however the RDF model disallows literal as subject. (As SPARQL in
>> query blocks, however SPARQL disallows path syntax in triple assertion
>> syntax)
> +1.  SPARQL could be fixed in the next version to allow path syntax in
> triple assertion syntax if the SPARQL WG is too tired to change that in
> SPARQL now.
>>      1.2. Attempting to limit use of "literals" in subject position to
>> only ^ predicates in grammar (Not as SPARQL and SPARQL disallows path
>> syntax in triple assertion syntax.)
> -0.5.  No need to complicate the grammar.
>> 3. Add both ^ property path syntax and "is ... of" syntax.
> -1.  To my mind, that would just add pointless complexity.  Standardize
> one or the other but not both.
Received on Sunday, 19 August 2012 02:54:11 UTC

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