- From: Dan Connolly <connolly@w3.org>
- Date: Mon, 30 Apr 2007 10:12:48 -0500
- To: "Booth, David (HP Software - Boston)" <dbooth@hp.com>
- Cc: public-grddl-comments@w3.org
On Mon, 2007-04-30 at 03:28 -0400, Booth, David (HP Software - Boston) wrote: [...] > > > 3. Are GRDDL transformations deterministic or not? A short answer to this question is: yes, they are; a transformation is a function: "... each GRDDL transformation specifies a transformation property, a function from XPath document nodes to ... RDF graphs." -- http://www.w3.org/2004/01/rdxh/spec#txforms some details seem to be a little out of kilter... I elided a spurious mention of RDF/XML documents there... the range of the function is RDF graph. grddl:TransformationProperty is a subclass of owl:FunctionalProperty. Oops; or rather... it's supposed to be... darn... looks like that got left out of the details of the vocabulary section. http://www.w3.org/2004/01/rdxh/spec#grddlvocab I should fix that to match the "Transformation Algorithms" section. [...] > > So, given that the WG decided to punt on the question of > nailing down the input XML infoset -- and that decision > by itself sounds reasonable -- the responsibility for > unambiguous results seems to fall on the transformation > property author. Although in general we may not know > what information set the XML document author intended, I > think it *is* reasonable to assume that the transformation > property author knows what XML infoset he/she intended. > > So how exactly can the transformation property author > assure unambiguous results? The spec seems to give no > advice: > http://www.w3.org/2004/01/rdxh/spec#txforms > [[ > Therefore, it is suggested that GRDDL transformations be > written so that they perform all expected pre-processing, > including processing of related DTDs, Schemas and > namespaces. > ]] > How? I see Dan's comment in the WG meeting about this: > http://lists.w3.org/Archives/Public/public-grddl-wg/2006Dec/att-0072/GRD > DL_Weekly_--_20_Dec_2006.html#item10 > [[ > Dan: if you want you transformation to do xinclude, then > make your transformations do xinclude > ]] > In accordance with Dan's comment, is the WG suggesting > that transformation property authors must re-implement the > xinclude spec if they want their results to be unambiguous? > > If so, how many other things would a responsible > transformation property author also have to routinely > re-implement in order to ensure unambiguous results? > > Why not permit the desired XML infoset treatment to > be easily specified explicitly? There's another W3C WG working on exactly this problem, so we note their solution might work well: [[ XProc: An XML Pipeline Language[XPROC], a language for describing operations to be performed on XML documents, has recently been published as a W3C Working Draft. It merits consideration for expressing more complex or sophisticated transformations which require control over the flow of processing through a variety of XML processing tools. Using XProc, one could apply a sequence of operations such XInclude, validation, and transformation to a document, aborting if the result of an intermediate stage is not valid, for example. ]] -- http://www.w3.org/2004/01/rdxh/spec#txforms > For example, for the > simple, non-namespace case, instead of defining the > grddl:transformation attribute, how about allowing the > author to choose between three attributes: > > - grddl:transformation, which might have standard > XML pipeline infoset semantics; As I noted earlier, we tried to find such a standard and came to the conclusion that the state of the art offers no standard. Did we miss something? > - grddl:unprocessedTransformation, which might have > semantics of NO infoset preprocessing; and > > - grddl:ambiguousTransformation, which might have the > ambiguous semantics of the current GRDDL draft. -- Dan Connolly, W3C http://www.w3.org/People/Connolly/ D3C2 887B 0F92 6005 C541 0875 0F91 96DE 6E52 C29E
Received on Monday, 30 April 2007 15:12:55 UTC