W3C home > Mailing lists > Public > public-rdf-dawg-comments@w3.org > July 2008

RE: SPARQL and string literal matching woes - spec inconclusive - try 2

From: Seaborne, Andy <andy.seaborne@hp.com>
Date: Mon, 7 Jul 2008 08:40:28 +0000
To: Richard Newman <rnewman@franz.com>
CC: Nuutti Kotivuori <naked@iki.fi>, "public-sparql-dev@w3.org" <public-sparql-dev@w3.org>, "public-rdf-dawg-comments@w3.org" <public-rdf-dawg-comments@w3.org>
Message-ID: <B6CF1054FDC8B845BF93A6645D19BEA34272AE6171@GVW1118EXC.americas.hpqcorp.net>
> -----Original Message-----
> From: Richard Newman [mailto:rnewman@franz.com]
> Sent: 6 July 2008 21:09
> To: Seaborne, Andy
> Cc: Nuutti Kotivuori; public-sparql-dev@w3.org; public-rdf-dawg-
> comments@w3.org
> Subject: Re: SPARQL and string literal matching woes - spec inconclusive -
> try 2
>
> Andy,
>
> Is this actually true? See the SPARQL Tests section of the table,
> which defines a match for two RDF terms. (Of course, they're not
> RDFterm-equal, so it produces a type error anyway.)
>
> -R

The dispatch to RDFTerm-equals is the place the type error is produced; it's a catch-all and as such must be last in the table.  It is not in the section for dispatch based on the understood types in the "XPath Tests" nor "XPath Arithmetic" section.  It captures the fact that for two literals "A = B" if they have the same datatype and lexical form (or lexical form and language tag) regardless of whether the SPARQL processor understands that datatype.

In that sense, anything has a dispatch entry but this one is different because it can produce a type error even though it matches, and it must be at the end of the dispatch possibilities for "=" and "!=".  It could equally well have been defined as partial mapping for the true case, not dispatching if they are not equal and dropping through to fall off the bottom of the table.

        Andy

>
> On  6 Jul 2008, at 11:07 AM, Seaborne, Andy wrote:
>
> > Not trickier - uses a different part of the spec :-)
> >
> > See sec 11 operator dispatch table.
> > http://www.w3.org/TR/rdf-sparql-query/#OperatorMapping

> >
> > Under (minimal) SPARQL,
> >
> > =   (value"^^xsd:string , "value" )
> >
> > has no entry in that table.  So it's a type error and the FILTER is
> > false.

Received on Monday, 7 July 2008 08:41:31 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 7 July 2008 08:41:31 GMT