- From: Henry S. Thompson <ht@inf.ed.ac.uk>
- Date: Tue, 27 Nov 2007 21:17:28 +0000
- To: www-tag@w3.org
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Further to discussion at the March 2007 f2f [1]. I've produced a new draft of _The elaborated infoset: A proposal_ [2]. As several editorial notes therein suggest, I'm not at all sure how to integrate this into Web Architecture. There are at least two (partially interdependent) questions this draft doesn't answer: 1) What is the role of the application in controlling the elaboration process? 2) What is the right model for the relationship between elaboration, understood as the specification/construction of an infoset, and application semantics, particularly in the case of mixed namespace documents? To illustrate the reason (1) is important, consider a bank transfer document, expressed in XML, and three XML applications: a) An XML editor; b) An XML validator (pick your favourite schema language); c) An XML banking application. The editor probably wants the document _as is_, without any elaboration. The validator probably wants as much elaboration as possible (but really that's up to the user). The banking application may want some but not all of the document to be elaborated: consider the case where its own banking markup semantics includes some form of encapsulation. So the document can't be said to have _an_ elaborated infoset: elaboration is in part controlled/parameterised by what the user of the document is _doing_ with it. The issue behind (2) is discussed at some length in Tim Berners-Lee's original thinking on this topic, as expressed in [3], particularly the sections entitled "Top-down Processing model" and "Software designs for top-down processing". The granularity of the implied interaction in that discussion is much finer than that in the draft elaboration proposal. It's not clear to me that a notion of elaborated _infoset_, as opposed to elaborated _infoitem_, has any utility if, for example, the possibility of embedding a fragment in language B inside a document in language B, where A and B have different requirements for quoting vs. elaboration. The interaction between the two questions arises as follows: are there actually any generic XML _applications_, that is, applications which process XML as XML, independently of its vocabulary-specific semantics, for which a non-application-specific notion of whole-document elaboration makes sense? Possible candidates include validation and style/query processing. The hard case for this that emerged in the f2f discussion [1] is that of a vocabulary-specific conditional construct with an XInclude inside a guarded branch, where the included material is a very large multimedia document access to which involves real cost to the user. This message is an invitation to open up discussion, since answers evidently are not being offered. . . ht [1] http://www.w3.org/2001/tag/2007/03/06-minutes#item10 [2] http://www.w3.org/2001/tag/doc/elabInfoset/ [3] http://www.w3.org/DesignIssues/XML - -- Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh Half-time member of W3C Team 2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440 Fax: (44) 131 650-4587, e-mail: ht@inf.ed.ac.uk URL: http://www.ltg.ed.ac.uk/~ht/ [mail really from me _always_ has this .sig -- mail without it is forged spam] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.6 (GNU/Linux) iD8DBQFHTIlrkjnJixAXWBoRAhJtAJ9cqr2FtTOP0kClHglphAZilka9HACcCLRM 84HZ9zwfdEuwwS0VlhipGCE= =ERR6 -----END PGP SIGNATURE-----
Received on Tuesday, 27 November 2007 21:17:45 UTC