- From: Jeni Tennison <jeni@jenitennison.com>
- Date: Mon, 19 Aug 2002 20:43:50 +0100
- To: public-qt-comments@w3.org
Hi, I think that there needs to be some clarification and consistency in the Data Model WD regarding whether the constructors/accessors/functions defined in the Data Model WD can raise errors and what happens when they do. I had been going to post a comment about error-checking in the node constructor functions. For example, I expected something about what happens if a comment is constructed with a value that contains "--" or what happens if an element is constructed with a sequence of attributes that includes two attributes with the same name. Then I thought that you'd probably left out these things deliberately because you wanted the host language for XPath (e.g. XSLT or XQuery) to determine what happens in these cases, and didn't want to specify error checking/handling within the data model. But now I've come to Section 5, where it says (in the 5th paragraph): An atomic value can be constructed from its lexical representation. dm:atomic-value takes a string and a corresponding atomic type and constructs an atomic value in such a way to be consistent with validation. In particular the construction takes into consideration the facets of the type. **If the string does not represent a valid value of the type an error is raised**... Is this mention of errors an oversight, or is there some rationale behind some errors being detected and others not? For what it's worth, I think that the data model *should* define all the error checking that goes on when constructing nodes and values, because that ensures that the various host languages of XPath detect the same set of errors. The host languages themselves should be able to decide what to do when an error gets raised, of course... Cheers, Jeni --- Jeni Tennison http://www.jenitennison.com/
Received on Monday, 19 August 2002 15:43:52 UTC