W3C home > Mailing lists > Public > public-xml-versioning@w3.org > April 2007

Re: Versioning Finding Updated

From: John Cowan <cowan@ccil.org>
Date: Tue, 3 Apr 2007 02:44:16 -0400
To: "Henry S. Thompson" <ht@inf.ed.ac.uk>
Cc: David Orchard <dorchard@bea.com>, www-tag@w3.org, public-xml-versioning@w3.org
Message-ID: <20070403064416.GB21877@mercury.ccil.org>

Henry S. Thompson scripsit:

> In section 3.8 "What Schema language(s)?" [1] you say "For example,
> writing a V2 compatible schema in W3C XML Schema requires special
> design, which is not required in a schema language such as RELAX NG."
> I'm not sure I understand what is meant here -- is there somewhere else
> in the document (or its companion) where this point is expanded a bit?

I don't know the specific answer, but what comes to mind is the UPA
constraint.  Given two similar schemas v1 and v2, it requires considerable
craft to create a WXS schema that will accept documents conforming to
either v1 or v2, whereas in RNG it's as simple as writing "v1 | v2".
See Norm's blog post at http://norman.walsh.name/2004/07/25/xslt20 .

It was dreary and wearisome.  Cold clammy winter still held way in this
forsaken country.  The only green was the scum of livid weed on the dark
greasy surfaces of the sullen waters.  Dead grasses and rotting reeds loomed
up in the mists like ragged shadows of long-forgotten summers.
        --"The Passage of the Marshes"          http://www.ccil.org/~cowan
Received on Tuesday, 3 April 2007 06:44:29 UTC

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