Re: keyrefs

Hi Eddie,

>> Adding Schematron-like rules to any complex type definition, on the
>> other hand... :)
>
> Since Schematron is built on top of XSLT, as soon as XPath support
> the PSVI this is exactly what we'll be able to do. And if we don't
> want to wait for the next XPath we can use Francis Norton's new
> "poor-man's PSVI...".

Yes. I was more thinking of perhaps something being incorporated in
the next version of XML Schema that would allow us to represent things
like 'this attribute or that element' without bugging out to
Schematron or RELAX NG.

>> Mixing the modular style of XML Schema with XPath is pretty nasty
>> (although perhaps XPath 2.0 will help, if it supports testing of
>> user-defined types).
>
> I think it will but I'm not entirely sure.

I guess we'll have to wait for the XPath WD :) The XQuery/XPath data
model includes types, but this doesn't necessarily mean that you're
able to *test* the type of an element. For example, the data model
might just include types so that it's possible to describe the
mechanism by which an XPath processor works out which primitive type
an element has as a value (just as the data model describes the Base
URI of a node but XPath has no way of actually accessing that as a
string). The XQuery/XPath operators document doesn't have anything
about user-defined types that I can remember, so if there is anything
my guess is it will be an axis.

Cheers,

Jeni

---
Jeni Tennison
http://www.jenitennison.com/

Received on Monday, 12 November 2001 05:30:20 UTC