- From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
- Date: Mon, 24 Feb 2003 16:58:34 +0100
- To: "Dave Beckett" <dave.beckett@bristol.ac.uk>, "Jeremy Carroll" <jjc@hplb.hpl.hp.com>
- Cc: "w3c-rdfcore-wg" <w3c-rdfcore-wg@w3.org>
> > The other question is: which X? I assume the choices are Exclusive > or Canonical, with/without comments. Did we get a recommendation or > suggestion from the commenters? Reagle says: (I recommend you use exc-c14n). see http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0128.html that leaves the comments issue open, but (realistically) excludes the preservation of namespaces that are not used. > > > > ===== > > 3 is now my preference - I realise it needs expansion, but > before I do that > > I wish to list pros and cons, and get feedback from WG. > > ===== > > > > Consider three use cases: > > A) cheap and cheerful RDF impl using embedded XHTML > > B) OWL or other semantically advanced use where it is desired that > > representation in domain of discourse is not implementation dependent. > > C) Embedding XSLT document inside and rdf:XMLLiteral (hence requiring > > support for preservation of not visibly used namespaces) > > > > > > 1: > > A - works > > B - doesn't really work, because of comments and not visibly > used namespaces > > C - might work depending on having an implementation that knows when to > > preserve not visibly used namespaces > > > > 2: > > A: expensive > > B: works > > C: does not work > > > > 3: > > A: works > > B: works > > C: does not work > > > > i.e. our current position works non-interoperably for XSLT in > RDF - a use > > case that we have not seen, and that is its only advantage over > soln 3 which > > interoperably does not work for XSLT in RDF. > > > > ==== > > > > If we go for soln 2 or soln 3 we have to reconsider whether we wish to > > preserve comments, and which not visibly namespaces we preserve. > > I suggest preserve comments, and no namespaces that are not > visibly used. > > OK, this is your X choice. Did DigSig group express a preference? exc-c14n - I do not have an axe to grind on the comments either way. > > > From my experience, I think preserving comments will be tricky to > implement on top of the C SAX API so slightly prefer not preserving > them. I will investigate, however. I have no preference on the > namespaces. If the comments are hard in some environments let's ditch them. > > Is 3 still too lax for "removing implementation variability from RDF/XML"? Yes. Reagle says (in the same msg): "what purpose is a canonicalization even serving if you are likely to get implementation variances? " I think this comment could be addressed editorially - not clear in which document though. e.g. "The design of rdf:XMLLiteral and its relationship to rdf:parseType="Literal" permits implementation variablity in the representation of rdf:XMLLiteral's in an RDF graph, but does not permit variability in the denotation of rdf:XMLLiteral's under RDF datatyped semantics." (requires wordsmithing) > > > BTW - if we go for 2 or 3 ARP will need updating - it has some > support for > > preservation of not visibly used namespaces. I could ask on > jena-dev whether > > anyone is using this feature. > > Yes, well, all the (updated) RDF parser implementations will have to > change for 2 or 3. Since there are some that already claim > conformance to the revised syntax. > I would have thought quite a lot already canonicalize anyway - if you do not worry about resources that is the easiest path; and I would be surprised if many do much with not visibly used namespaces. Do we know? If we were to make a change we should IMO ask the parser implementors who have declared victory for their input. Jeremy
Received on Monday, 24 February 2003 10:58:42 UTC