Re: ASN.1 => XML Schema questions

"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 for
> example), but it's just that W3C XML Schema decided not to allow them
> for some reason.
> 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.

There is a third possibility that might not be as awful as it seems to
be at first glance... a validation process in 2 phases can be developed:
a XSLT transformation produces a normalized or canonical version of the
document and performs some application dependent checks and a schema
language finishes the job.

In this case, the transformation would "reorder" the sequences of ab|ba
into sequences of ab that can be validated using W3C XML Schema or even
a DTD.


> regards,
> ----------------------
> K.Kawaguchi
> E-Mail:

Pour y voir plus clair dans la nebuleuse XML...
Eric van der Vlist   

Received on Tuesday, 26 June 2001 17:20:56 UTC