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Re: ✅ Literals as subjects Re: Toward easier RDF: a proposal

From: Dan Brickley <danbri@danbri.org>
Date: Thu, 22 Nov 2018 07:31:38 -0800
Message-ID: <CAFfrAFoCeAuezWC6o_14pS_n_H3heQtjdg=O-DPCL+sG+HZYVQ@mail.gmail.com>
To: Tim Berners-Lee <timbl@w3.org>
Cc: David Booth <david@dbooth.org>, Semantic Web <semantic-web@w3.org>, Dan Brickley <danbri@google.com>, "Sean B. Palmer" <sean@miscoranda.com>, Olaf Hartig <olaf.hartig@liu.se>, Axel Polleres <axel@polleres.net>
On Thu, 22 Nov 2018, 05:04 Tim Berners-Lee <timbl@w3.org wrote:

>
>
> On 2018-11 -21, at 22:40, David Booth <david@dbooth.org> wrote:
>
> 7. Literals as subjects.  RDF should allow "anyone to say
> anything about anything", but RDF does not currently allow
> literals as subjects!  (One work-around is to use -- you guessed
> it -- a blank node, which in turn is asserted to be owl:sameAs
> the literal.)  This deficiency may seem unimportant relative
> to other RDF difficulties, but it is a peculiar anomaly that
> may have greater impact than we realize.  Imagine an *average*
> developer, new to RDF, who unknowingly violates this rule and
> is puzzled when it doesn't work.  Negative experiences like
> that drive people away.  Even more insidiously, imagine this
> developer tries to CONSTRUCT triples using a SPARQL query,
> and some of those triples happen to have literals in the
> subject position.  Per the SPARQL standard, those triples will
> be silently eliminated from the results,[13] which could lead
> to silently producing wrong answers from the application --
> the worst of all possible bugs.
>
>
> Agreed.
>
> I thought we had fixed that in some later spec but I guess not.
>

https://www.w3.org/TR/rdf11-concepts/#section-generalized-rdf is the
closest afaik, maybe parts of the Semantics and SPARQL specs are quietly
permissive too, I forget...

All code I have written, like cwm and rdflib.js, allows the same things in
> subject and object positions.  Life is too short for arbitrary unnecessary
> asymmetry.
>
> timbl
>
>
Received on Thursday, 22 November 2018 15:32:14 UTC

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