Re: [xsl] Request help in understanding: node instance of schema-element(node)

Subject: Re: [xsl] Request help in understanding: node instance of schema-element(node)
From: Wendell Piez <wapiez@xxxxxxxxxxxxxxxx>
Date: Mon, 28 Jan 2008 16:23:40 -0500
At 01:06 PM 1/28/2008, Tony Coates wrote:
In my experience, schemas (of whatever variety) have been used for two
purposes, which have historically been joined at the hip, but which are
actually quite distinct.

One is "validation", which is to say, determine whether a document or
parts of a document conform to an expected or required type. ("Schema as

The other is for type annotation or even for binding of XML data (which
natively takes the form of sequences of characters) to data types.
("Schema as jig.")

I would also add to that "Schema as template", where a Schema is used to provide guidance to an author (especially when using a Schema-aware editor). For example, you may not care about document order for validation or binding, but you might impose an order for authoring, just because human editors often work better with a "template" where each data item is in a known location relative to other data items.

That's a good point, Tony. I'd have thought that would be another case of "schema as jig", but you're right, it's very different from the type-annotation example. Indeed, as has been pointed out in the past (and to bring this back to XSLT), type annotation could be considered a sort of transformation, whose spec just happened to be given in a schema. And transformations that rely on it might well be accomplished in pipelines rather than in scenarios relying on "validation" (which then relates us to another ongoing thread).

But "templates" are for people, which is something else entirely.


Wendell Piez                            mailto:wapiez@xxxxxxxxxxxxxxxx
Mulberry Technologies, Inc.      
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