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RE: Schema for schemas and XML schema DTD

From: Fuchs, Matthew <matthew.fuchs@commerceone.com>
Date: Thu, 2 Nov 2000 16:39:08 -0800
Message-ID: <4C4A7BE77CE1D311A1D200508BA38C1202F35258@venus.commerceone.com>
To: "'www-xml-schema-comments@w3.org'" <www-xml-schema-comments@w3.org>
Cc: "Michel, Adrian" <adrian.michel@commerceone.com>, "Fuchs, Matthew" <matthew.fuchs@commerceone.com>

Non-validating processors are not required to read the external subset:

"Non-validating processors are required to check only the document entity,
including the entire internal DTD subset, for well-formedness." [1] 
There is no official status for a non-validating processor which is required
to process the external subset (one could reasonably parse the above as
prohibiting use of the external subset), therefore I don't think it would be
appropriate to require that intermediate level of behavior.  In fact, the
spec itself frowns on just the behavior you suggest:
"For maximum reliability in interoperating between different XML processors,
applications which use non-validating processors should not rely on any
behaviors not required of such processors. Applications which require
facilities such as the use of default attributes or internal entities which
are declared in external entities should use validating XML processors." [2]
As interoperability is also a principle mentioned in our requirements, I
think the WG would have to disparage using the kind of processor you mention
and would need to insist on a fully-validating processor, as the XML 1.0
spec recommends.
[1] http://www.w3.org/TR/2000/REC-xml-20001006#sec-conformance

[2] http://www.w3.org/TR/2000/REC-xml-20001006#safe-behavior

From: "Biron,Paul V" 
Subject: RE: Schema for schemas and XML schema DTD

> -----Original Message-----
> From:	Fuchs, Matthew 
> Sent:	Thursday, November 02, 2000 3:01 PM
> Subject:	RE: Schema for schemas and XML schema DTD
> > -----Original Message-----
> > Subject: Re: Schema for schemas and XML schema DTD
> > 
> As you well know, XML 1.0 specifies two levels of conformance -
> well-formed
> and validating.  The Schema for schemas currently requires a _validating_
> processor.
I won't comment on the general issue of whether or not the schema for
schemas should reference a DTD which changes the infoset, but...

doing so does not require schema processors to be built using a validating
processor...it simply requires a non-validating processor which reads the
external subset...quite a different thing.

Received on Thursday, 2 November 2000 19:39:19 UTC

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