W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > March 2003

sketch of new proposal reagle-01 reagle-02 tex-??

From: Jeremy Carroll <jjc@hpl.hp.com>
Date: Wed, 12 Mar 2003 10:53:23 +0100
To: w3c-rdfcore-wg@w3.org
Message-Id: <200303121053.23136.jjc@hpl.hp.com>

At the telecon I was actioned to bring a new proposal on the reagle issues.
This is a sketch intended to allow members of the WG who were absent at the 
telecon to comment. I will expand the details later (not on semantics - which 
I intend to leave to Pat's discretion)

  with comments
  c14n done in syntax doc
  implementation note added to concepts

+  7.2.17 changed to indicate that exc-canonicaliztion with comments and with 
empty  InclusiveNamespaces PrefixList. is performed.
+   add new link from part where it is said that use of N-Triples is not 
required to implementation note in concepts

+  change lexical space of rdf:XMLLiteral to be strings that are root element 
content of canonical XML documents
+  change mapping of rdf:XMLLiteral to be a string concatenation
'<rdf-wrapper xml:lang="'

+  add implementation note at end of abstract syntax section

This section describes an *abstract* syntax which describes
equality of literals and equivalence of graphs. This is the
syntax over which the foraml semantics are defined.
Implementations are free to represent literals and RDF graphs in 
any other equivalent form. As a first example: language tags may be
represented in their original case, and language tag comparison would
then be a case insensitive string comparison. As a second example:
literals with datatype rdf:XMLLiterals can be represented in a non-canonical
format, and canonicalization performed during the comparison between two
such literals. In both of these examples, the comparisons may be 
being performed either between syntactic structures or
between their denotations in the domain of discourse.
Implementations that do not require such comparisons can
hence be optimized.

+ follow concepts as appropriate
  (Note: there is still rdf:XMLLiteral as a special case because even though 
the mapping is simplified, it is still there, and it still requires the lang 
tag as an argument).



The first example with language tag case is intended to:
- be easy to understand
- partially address an issue raised by Tex Texin (possibly on behalf of I18N 
WG), no ID yet.

The second example is intended to address part of my action.


The suggested wording for the lexical and value spaces of rdf:XMLLiteral in 
concepts  permits the following:

<rdf-wrapper xml:lang="">
  <eg:a xmlns:eg="eg:a" xmlns:unused="eg:b"></eg:a>

This does not correspond to any RDF/XML document.
A more complicated wording:
The value space
 is the set of all XML documents that: 

+ Have root element tag: <rdf-wrapper>
+ Have no attributes on the root element other than xml:lang
+ are Canonical XML [XML-C14N] (with comments).

+ which are unchanged when transformed using the exclusive canonicalization
with comments and with empty namespace prefix list
+ which have no namespace declarations that are not visibly used [EXC-C14N]
could avoid this.

(The example document would have the declaration for xmlns:unused deleted by 
such a transform, and hence be excluded from the datatype).
Is that better or worse?

Received on Wednesday, 12 March 2003 04:52:51 UTC

This archive was generated by hypermail 2.3.1 : Wednesday, 7 January 2015 14:54:04 UTC