- From: Dan Connolly <connolly@w3.org>
- Date: Tue, 26 Jun 2001 16:19:33 -0500
- To: "K.Kawaguchi" <kohsukekawaguchi@yahoo.com>
- CC: Geoff Elgey <elgey@dstc.qut.edu.au>, xmlschema-dev@w3.org
"K.Kawaguchi" wrote: > > > I know that N! alternatives sounds daunting when performing schema > > validation -- is this why <all> cannot have repetitions or be nested > > within a <sequence> ? > > There are algorithms that can validate <all> nested within <all>, or > whatever (see http://www.thaiopensource.com/relaxng/jing.html for > example), but it's just that W3C XML Schema decided not to allow them > for some reason. I'm pretty sure the reason is that in W3C XML Schema validation, the result includes not just a "yes, this is valid"/"no, not valid" but also "and this part of the input matched this part of the schema" i.e. "it has this type, is associated with this annotation" etc. [I wish we had revised our requirements document to point this out more clearly; it's a requirement that motivates a lot of decisions that otherwise don't look nice.] > So your options are either > > - stick to W3C XML Schema and make a compromise by using (a|b)* rather > than (ab|ba)*. > - or switch to another schema language that allows you to express what > you want. Keep in mind that the other languages won't give you type/annotation info as a result of checking. > regards, > ---------------------- > K.Kawaguchi > E-Mail: kohsukekawaguchi@yahoo.com -- Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Tuesday, 26 June 2001 17:19:40 UTC