Re: [xml-dev] RE: Schematron Best Practice: A Schematron schema's a

[noah_mendelsohn@us.ibm.com]

Rick Jelliffe writes:

> So even though both XSD and Schematron are quite matched for the
> information they can carry, in Schematron you would expect that the user
> would get the full text, while in XSD you have to try to try tofigure 
out
> how to make your application deliver annotation information as 
> part of the
> user message.

Yes, indeed.  Interestingly, this highlights a somewhat deeper difference 
in focus between XSD and Schematron, though it's one that I only became 
conscious of after I started thinking about the integration of the two. 
Specifically, I think Schematron is implicitly focussed to a signficant 
degree on situations in which a human user (or maybe a text log) will be 
the recipient of a report on how the instance fared with respect to the 
Schema.  XSD is at least implicitly a bit more aimed at scenarios in which 
the validation will be embedded in some larger processing context, perhaps 
a database system, which will get its validation reports through some API. 
 The consistent means of providing report "text" in Schematron seems 
particularly suited to providing reports to human users, and is arguably a 
bit less convenient as the basis for an interface between software layers.

I'm not trying to over-emphasize the differences, but I've gradually come 
to believe that they are of some significance.  Indeed, one of the things 
we had to decide when putting XPath-based assertions into Schema 1.1 was 
whether to follow Schematron's lead in providing primarily textual 
reports.  In the context of XSD in particular, it seemed more useful to 
integrate a failure of an XPath assertion into the rest of the XSD 
validation-reporting frameword (I.e. [validity] properties, etc. in the 
PSVI), and indeed that's what we're currently planning to do.

--------------------------------------
Noah Mendelsohn 
IBM Corporation
One Rogers Street
Cambridge, MA 02142
1-617-693-4036
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