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Re: Section 3.2.2.4 text on extensibilty

From: Tim Bray <tbray@textuality.com>
Date: Mon, 07 Jul 2003 16:21:25 -0700
Message-ID: <3F0A0075.4050607@textuality.com>
To: David Orchard <dorchard@bea.com>
Cc: www-tag@w3.org

David Orchard wrote:

> Here's a rough start to the extensibility and versioning section of the web
> arch document, and a small change proposed to 3.2.

I'm basically OK with the content here, although I suspect that Ian 
could usefuly tighten the whole thing up and shrink it a bit.  Couple of 
points:

> Backwards compatibility means that existing sending agents can use receiving
> agents that have been updated, and forwards compatibility means that newer
> sending agents can continue to use existing recieving agents.

Er, really?  I would say forward compatibility means that the new 
software can read the old data.  Or do I have this backward?

> XML and Schema languages require that schemas have deterministic content
> models.  An explanation from the XML 1.0 specification, "For example, the
> content model ((b, c) | (b, d)) is non-deterministic, because given an
> initial b the XML processor cannot know which b in the model is being
> matched without looking ahead to see which element follows the b."

XML 1.0 DTDs require this, and so does XML Schema.  RelaxNG doesn't.  I 
don't think this is architectural in the slightest.

-- 
Cheers, Tim Bray
         (ongoing fragmented essay: http://www.tbray.org/ongoing/)
Received on Monday, 7 July 2003 19:21:27 UTC

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