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Re: Adding a datatype for HTML literals to RDF (ISSUE-63)

From: Andy Seaborne <andy.seaborne@epimorphics.com>
Date: Wed, 09 May 2012 12:22:45 +0100
Message-ID: <4FAA5385.4090403@epimorphics.com>
To: Ivan Herman <ivan@w3.org>
CC: Steve Harris <steve.harris@garlik.com>, Richard Cyganiak <richard@cyganiak.de>, public-rdf-wg@w3.org


On 09/05/12 11:54, Ivan Herman wrote:
> As Richard emphasized in his mail, XML Literal and, if approved,
> HTML5 Literals are optional. If implementation do not want to
> implement equality checking on these literals, that is fine. However,
> if they _do_ want to do that, than we should define what equality
> means. That is where the value space issue comes into the picture.
>
> I think that real issue we have to solve, however, is to keep the
> lexical space as unconstrained as possible. The current XML Literal
> definition seemed to be very ambiguous in this respect and it was
> never 100% clear whether an RDF file in, say, Turtle, should include
> a canonical XML for the literal or not.

My reading of the current state:

The lexical space of rdf:XMLLiterals is exclusive Canonical XML (RDF 
concepts).

The requirement to perform canonicalization is in the RDF/XML syntax doc 
and not elsewhere.  That does apply to Turtle or N-Triples.

A non-canonical literal for ^^rdf:XMLLiteral is an illegal literal.
Like writing "foo"^^xsd:integer.

> This led to long discussions
> among, eg, RDFa implementers at a time on what _exactly_ should be
> generated by an RDFa processor. If we say that the lexical space is
> very lax, and we have a clear definition of equality (whether we
> define equality via Infosets or DOM tree equality is a detail in this
> respect) then the situation becomes clear and, because these
> datatypes are not required, there is no issue with conformance
> either.

What did RDFa decide?

	Andy

>
> Ivan
Received on Wednesday, 9 May 2012 11:23:30 GMT

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