- From: Harry Halpin <hhalpin@ibiblio.org>
- Date: Wed, 13 May 2009 16:42:54 +0200
- To: Phil Archer <phil@philarcher.org>
- Cc: Dan Connolly <connolly@w3.org>, public-powderwg <public-powderwg@w3.org>, www-tag@w3.org
On Wed, May 13, 2009 at 4:07 PM, Phil Archer <phil@philarcher.org> wrote: > Hi Dan, > > Thanks as always, for taking the time to look at our work. We've been > through your comments, done some tests, made some discoveries and made some > minor tweaks to a couple of things. > > Comments inline. > > > Dan Connolly wrote: >> >> In our 23 apr meeting*, the TAG reviewed my comment about >> the testcases not working: >> powder-test/grddl/powder002.xml is 404? >> http://lists.w3.org/Archives/Public/public-powderwg/2008Dec/0006.html >> >> and decided to endorse it. It's hard for us to review POWDER >> with the test materials in their present state. >> >> Is there some way of using the test materials in their present >> state that we're just not aware of? Or are they actually broken >> and in need of a fix? > > Taking your original e-mail, the test suite URI works: > http://www.w3.org/TR/powder-test/#grddl and if you follow the links from > there to, say, > http://www.w3.org/TR/powder-test/tests/grddl_tests/Manifestgrddl002.rdf the > files referenced within that are all present and correct. i.e. there are no > 404s in the chain. I verified this with a script, accessible at the very end > of our implementation report [1]. In other words, past errors in this regard > have already been corrected. > > The more substantive point you've raised concerns our GRDDL references. > > We did some tests with two applications: the W3C GRDDL service (which is > based on Redland) and Jena which uses the Saxon XSLT engine. Both > applications gave error messages but for different reasons. > > We can't be 100% sure but it seems very likely that the reason that Redland > fails is because we use XSLT2. > > We are more sure that the reason that Jena fails is that it doesn't parse > XML namespace documents to find the data-view transformation link - which is > the GRDDL method we use. > > Redland gives a parsing error, Jena (Saxon) tries to validate against the > RDFa DTD and throws out many lines of errors. > > It would be good to find a GRDDL implementation that supported both XLST 2 > and schema-identified transformations. If such an application exists, we'd > be interested to see the result (but I can't find any). > > We /have/ however made a slight change since your e-mail. Originally, we > published 2 separate XSLTs. One does the POWDER to POWDER-BASE > transformation for which XSLT 2 functions are required) and the second gets > you from POWDER-BASE to POWDER-S (this just uses XSLT 1). Recall that the > only difference between POWDER and POWDER-BASE is that in the latter, all > IRI constraints are defined as regular expressions. In the former, we > support more friendly constraints like 'inclduehsosts.' > > Originally we had data-view:transform links to both of those stylesheets > separately in the POWDER schema which actually comprises multiple files. > That was a mistake that we've now corrected. The GRDDL reference now is to a > single XSLT that is an exact copy of the P to P-B stylesheet with an > additional <xsl:include /> element pointing to the P-B to P-S transform > (unchanged). > > We've tested this combined file in Saxon (directly and via W3C XSLT service) > and it works fine. For example, if you put GRDDL test 2 and the combined > XSLT into the W3C service, you get the (correct) result as can be seen at > http://tinyurl.com/q9ljkh. > > The separate XSLTs are still available and will remain so, along with a > script I wrote that does the P to P-B transformation, so that it is possible > to do the full transformation through to POWDER-S without using XSLT 2. > > It's clear that we're pushing the limits of what GRDDL can do, however, > technologies other than XSLT 1 are expressly allowed in the GRDDL spec, as > are schema-defined transformations. > > I hope this answers your concerns. Yes, I concur with Phil. This is precisely a problem due to the combination of XSLT2, schema include support, and GRDDL it appears, *not* a broken test-case for POWDER per se. Note that due to XSLT2 not being requested (and I did ask I believe if there was interest), we did not have this test-case in the GRDDL Test Cases. However, my question for Phil: Is it possible to do this without schema includes or XSLT2? I assume the answer is no, but if this is mission-critical code, then it would be better to have everything done in a single schema without schema includes and using XSLT 1. Of course, I am assuming POWDER has excellent reasons for using XSLT2+schema includes. > Phil. > > > > > > [1] http://www.w3.org/2007/powder/Group/features.html >> >> >> * minutes pending; draft in member space: >> http://lists.w3.org/Archives/Member/tag/2009Apr/att-0051/23-minutes.html >> >> p.s. tracker, this is re ACTION-262 >> > > -- > > Phil Archer > http://philarcher.org/www@20/ > > i-sieve technologies | W3C Mobile Web Initiative > Making Sense of the Buzz | www.w3.org/Mobile > >
Received on Wednesday, 13 May 2009 14:43:30 UTC