- From: <Paul.V.Biron@kp.org>
- Date: Thu, 9 Mar 2006 10:34:48 -0800
- To: mike@saxonica.com
- Cc: ElektonikaMail@frink.w3.org, rjelliffe@allette.com.au, xml-dev@lists.xml.org, xmlschema-dev@w3.org, xmlschema-dev-request@w3.org
> The reference is W3C-member restricted. Right, I forgot about that. I'll fire the proposal text off to rick personally, because his input would be a good data point for the WG...since this is the main topic for the telcon on friday. > It might be that we've reached the stage where we can't afford to do things > properly so we have to do them cheaply. If that's the case, then this is > probably the right way forward. However, one needs to be aware of its > limitations. Having the schema WG bless a subset of ISO schematron for use in appinfo is also not my prefered approach, but I have proposed it because: 1) it does handle many of the important use cases and 2) people are currently doing this already, and it would be good if W3C somehow acknowledged this. > One way of doing co-occurrence constraints is to think in terms of a > "computed xsi:type" where the effective value of xsi:type on an element is > computed as the result of an XPath expression in the schema, applied to the > element instance as context node. This expression can default to > "@xsi:type", so the current xsi:type facility becomes just a special case. This is what some co-constraints proponents have called "conditional types". While this approach has many things going for it, I think it has one potential drawback. It is unclear how data binding tools would support the conditional assignment of types. I'm not saying that it couldn't be done but I've yet to seen anyone spell out how to handle it. Mind you, I'm not the biggest fan of data binding tools...but my user community feels they are very important so I'd like to know what the binding tool vendors would do with conditional types before walking too far down that path. pvb
Received on Thursday, 9 March 2006 18:35:06 UTC