- From: Dave Peterson <davep@iit.edu>
- Date: Sat, 5 Jul 2008 00:49:47 -0400
- To: Bijan Parsia <bparsia@cs.man.ac.uk>
- Cc: "C. M. Sperberg-McQueen" <cmsmcq@acm.org>, Alan Ruttenberg <alanruttenberg@gmail.com>, www-xml-schema-comments@w3.org, OWL Working Group WG <public-owl-wg@w3.org>
At 10:22 PM +0100 2008-07-04, Bijan Parsia wrote: >Good point. Of course one could define several >sorts of equality relation that were sensitive >to different aspects of the values and their >types. > >However: > http://www.w3.org/TR/xmlschema-2/#equal > >"for any a and b in the ˇvalue spaceˇ if a = b, >then a and b cannot be distinguished (i.e., >equality is identity)" > >So, uhm,... I think saying "equality is not >identity" is at least not the most *obvious* >reading of the spec :) > >>It's further true that XSD says that for its purposes, it chooses to >>define its equality and order relation in such-and-such a way. But >>it explicitly says that adopters of the datatypes should feel free >>to redefine equality and order (among other things) as they see fit. > >I found: > >"""Note: "Equality" in this Recommendation is >defined to be "identity" (i.e., values that are >identical in the ˇvalue spaceˇ are equal and >vice versa). Ah. You are looking at XSD 1.0 (2d ed); I'm talking WRT 1.1, which is publicly available in its second "Last Call Working Draft" at http://www.w3.org/TR/xmlschema11-2/ . One change between 1.0 and 1.1 is that equality is no longer always identity. (For most datatypes, it is, but for a few it is not. In particular, precisionDecimal, float, double, and the various date/time datatypes the two are not the same. Since the 1.1 LCWD went out for public comment on or about 20 June, I tend to interpret comments as being WRT 1.1. Sorry about the confusion. -- Dave Peterson davep@iit.edu
Received on Saturday, 5 July 2008 04:53:11 UTC