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Re: [xml-dev] version numbers and infosets

From: Karl Waclawek <karl@waclawek.net>
Date: Tue, 23 Jul 2002 15:18:52 -0400
Message-ID: <004d01c2327d$c7cc48f0$9e539696@citkwaclaww2k>
To: <xml-dev@lists.xml.org>
Cc: <xml-editor@w3.org>


> > OK, so let's say I have an XML 1.0 document, which is also
> > well-formed 1.1. But all I have is an XML 1.1 parser, and the
> > XML 1.1 specs say that the version number must be 1.1.
> > Am I not allowed to process it?
> 
> Every 1.1 parser, as a matter of high-quality implementation, should
> accept 1.0 documents as well.

I agree with you.
But if this is not a requirement of such parsers, the problem above still exists.

Anyway, for some time we may have to deal with a mixture of
1.0 and 1.1 documents being parsed by a mixture of 1.0 and 1.1 parsers.
The practical goal I am after simply is: Don't make the specs
prevent us from parsing when it would be practical to do so.

So far I have seen two rules that make some sense:

1) A document must have the lowest version number it conforms to
2) A parser conforming to a specific XML version must also
   conform to all lower versions

Are these rules part of any spec?

If followed, that should make it rare that we have a
"version mismatch" situation. However, in practice I suspect
we will have the situation where a 1.1 document is passed to
a 1.0 parser, simply because the parser is not available in an
upgraded version yet, or because the rules above are not followed.

Karl
Received on Tuesday, 23 July 2002 15:19:00 GMT

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