Re: Question about number types

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 04:53:09 UTC