Re: [dita] Namespaces and Schemas: Some Initial Findings and XSLT Implications

[Paul Grosso <pgrosso@arbortext.com>]

At 18:38 2004-06-28 -0500, Eliot Kimber wrote:

>The problem turned out to be that the topic2html.xsl style sheet is written entirely against the class mappings, which is what it should do, but because those class mappings are defined in the schema equivalent of "fixed" attributes, Saxon doesn't see them because the open source version of Saxon 8 isn't schema aware. Doh!

I don't know any details, but it seems odd that you can't get saxon
to work with attribute defaults (I assume it doesn't matter whether
they are "fixed" or not).  You might want to shoot an email to
Michael Kay <mhk@mhk.me.uk> to see if you're missing something
(or to see if he has near term plans to fix this).

On the other hand, I'm tempted to say that, if this is true, Saxon 8
is broken and don't use it, but that's not a reason to change DITA.
There are other XSLT processors that work properly.

paul


>This means, that from a practical standpoint, until more XSLT processors are schema aware we must have some other way to provide the DITA mapping attributes (and/or Schema-level class information) to XSLT processors. I think this can be done through a SAX filter using a schema-aware processor such as Xerces 2.6. I verified that with Xerces' DOM implementation I could get access to the schema-supplied defaulted attributes but when I passed that DOM to Saxon 7, Saxon didn't see them. Not sure why, but it probably has to do with the way Saxon's DOMSource class is implemented (the class that makes a DOM available to the XSLT processor). If someone thinks this *should* work let me know.
>
>In my testing with Xerces it did not complain about the DITA schemas but Saxon SA 8 did (both the base IBM DITA 1.3 schemas and my modified versions), making it impossible to actually process the documents with Saxon SA 8 (the commercial schema-aware version of Saxon). Doh!
>
>Note that this problem with defaulted attributes is a problem for anyone doing schema-based XML processing with XSLT, not just a DITA problem. It's just that DITA relies on the use of fixed attributes to a degree that few other XML applications do. But for example all the technical documentation DTDs I create depend on some sort of DITA-type class mapping to one degree or another, largely so that processing such as XSLTs can be simplified.
>
>Cheers,
>
>Eliot
>-- 
>W. Eliot Kimber
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