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Re: namespace coercion may not interoperate because of parser inconsistency

From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
Date: 09 Sep 2002 08:58:16 +0100
To: "Paul Kiel" <paul@hr-xml.org>
Cc: <xmlschema-dev@w3.org>
Message-ID: <f5by9abbnmv.fsf@cogsci.ed.ac.uk>

"Paul Kiel" <paul@hr-xml.org> writes:

> I believe I wrote about one of these situations before, but I
> thought I would add a second issue, and reiterate the first.  It is
> regarding namespace coercion.  I do like how powerful this technique
> is but find parser implementation maddeningly inconsistent.  I have
> a suite of about a half dozen parsers that I test with to make sure
> our schemas are interoperable.  However, they implement namespace
> coercion inconsistently.  For other reasons, we are moving to a
> different namespace usage, but our experience has taught us some
> things about this technique that I wanted to share (and hopefully
> save others the manual hair loss at trying to figure this out).
> Here are the scenarios.
> Scenario 1 - one slave, two nested masters
> schema A (ns="A")  
>           imports B (ns="B") 
>           includes C (ns="")
> schema B (ns="B") 
>           includes C (ns="")
> In this case, you want schema C to be coerced into both the A
> namespace and B namespace in schema A. Some parsers coerce into
> both, others only into one of the namespaces.

Yup, early releases of XSV got that wrong -- the REC is clear that
it's _schemas_ that are included, no schema documents, so there's
really no doubt that doing two coercions is correct.

> Scenario 2 - two slaves, one master
> schema D (ns="D")  
>           includes E (ns="")
> schema E (ns="") 
>           includes F (ns="")
> In this case, you simply want everything (E and F) to be coerced
> into the D namespace, the slaves are merely nested.  Some parsers
> coerce both the nested dependents, others will only coerce the first
> level, or E only.

Same reason as above -- coercing the whole schema corresponding to the 
E schema DOC, which consists of components corresponding to both doc E 
and doc F, is correct.

  Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
          W3C Fellow 1999--2002, part-time member of W3C Team
     2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440
	    Fax: (44) 131 650-4587, e-mail: ht@cogsci.ed.ac.uk
		     URL: http://www.ltg.ed.ac.uk/~ht/
 [mail really from me _always_ has this .sig -- mail without it is forged spam]
Received on Monday, 9 September 2002 03:58:27 UTC

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