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Re: XML literals

From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Date: Wed, 13 Aug 2003 17:43:18 +0200
To: <w3c-rdfcore-wg@w3.org>

The main planks of Pat's text from


seemed to get support at the RDF Core WG telecon on Friday, I was actioned
to move the conversation forward, and ensure that Martin and I18N were in on
My understanding is that the main goal was to avoid any possibility of
confusing XMLLiteral with xsd:hexBinary as in Martin's test case.

I also am trying to adequately address Patrick's concerns while changing
Pat's text as little as possible.

Brian used the term "XML fragment" at the telecon, I am however sticking
with Pat's "XML value" because of the existence of


which makes Brian's preferred term misleading.
I would be happy to consider other words for XML value.

For completeness I also include stuff on the lexical space, since there was
some concern that the wording is not about Unicde strings ... and the word
"corresponding" ...

I have numbered the notes for the sake of this e-mail, further discussion

Patrick - please indicate whether the last two notes (2,3) adequately
address your concerns. (3) ended up perhaps more geared towards some of
Martin's concerns.

I ended up unclear as to whether note 2 was wanted by the WG or not.

The lexical space
  is the set of all strings which:
  + are well-balanced, self-contained XML data [XML];
  + correspond  under [UTF-8] encoding to exclusive Canonical
    XML (with comments, with empty InclusiveNamespaces
    PrefixList ) [XML-XC14N];
  + when embedded between an arbitrary XML start tag and an end tag
    correspond to a document conforming to XML Namespaces [XML-NS]

The value space is a set of entities, called XML values, which is:
  + disjoint from the lexical space
  + disjoint from the value space of any XML schema datatype [XML-SCHEMA2]
  + disjoint from the set of Unicode character strings [Unicode]
  + in 1:1 correspondence with the lexical space.

The lexical-to-value mapping
   is a one-one mapping from the lexical space onto the value space,
   i.e. it is both injective and surjective.

Note (1): Not all lexical forms of this datatype are compliant with XML 1.1
[XML 1.1]. If compliance with XML 1.1 is desired, then only those that are
fully normalized according to XML 1.1 should be used.

Note (2): XML values can be thought of as the [XML Infoset] or
the [XPath] nodeset corresponding to the lexical form, with an appropriate
equality function.

Note (3): RDF applications may use additional equivalence relations, such as
that which relates an xsd:string with an rdf:XMLLiteral corresponding to a
single text node of the same string.


I seem to recall concern about putting too much into notes. Either the stuff
is sufficiently important to go into the design, or it isn't.

This may be sufficient to kill notes (2) and (3). I am reluctant to drop
note (1) since the RDF specs have largely followed charmod on NFC which puts
us into a somewhat anomolous position between XML 1.0 and XML 1.1 ...

If the notes add clarity then it is probably best to keep them.
Received on Wednesday, 13 August 2003 11:45:50 UTC

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