- 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>
"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.
ht
--
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