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Re: SV: What's a valid instance...James Clark

From: C. M. Sperberg-McQueen <cmsmcq@acm.org>
Date: Thu, 22 Mar 2007 09:31:43 -0600
Message-Id: <24983DAF-95C4-40F6-9CB9-47A1A7D8A701@acm.org>
Cc: "C. M. Sperberg-McQueen" <cmsmcq@acm.org>, "Bryan Rasmussen" <BRS@itst.dk>, "Pete Cordell" <petexmldev@tech-know-ware.com>, xmlschema-dev@w3.org
To: noah_mendelsohn@us.ibm.com

On 22 Mar 2007, at 08:50 , noah_mendelsohn@us.ibm.com wrote:

> I believe that in your example, the <bar/> is not valid, because  
> there's
> no global declaration for it.

That will be valid (with [validation attempted] = none) if
validation is initiated in 'lax' mode (third bullet item in
the list of ways to initiate schema validity assessment in
section 5.2 of XSD 1.0, called 'lax wildcard validation' in
the drafts of 1.1).  Only if you specify what 1.1 calls
'strict wildcard validation' will the processor know that
you want an error raised because 'bar' has no declaration.
And even then the PSVI on the element will say [validity]=valid;
the difference between lax and strict wildcard validation is
visible only from the point of view of the caller, not from
the PSVI.

> This has been discussed many times.  In my mind, it was a tradeoff....

In addition to the rationales you mention, I'd also mention
that specifying a required root tends to make reuse of
schema modules in other contexts harder.

--C. M. Sperberg-McQueen
Received on Thursday, 22 March 2007 15:31:49 UTC

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