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Re: Schema for schemas and XML schema DTD

From: Jonathan Robie <Jonathan.Robie@SoftwareAG-USA.com>
Date: Fri, 03 Nov 2000 15:09:51 -0500
Message-Id: <5.0.0.25.0.20001103150046.0202dfe8@127.0.0.1>
To: www-xml-schema-comments@w3.org
Henry Thompson wrote:

>Yes it would.  All the defaults in the DTD just re-interate defaults
>already expressed in the prose (or the schema for schemas).  There are
>three ways a conforming processor can be built:

[!!! SNIP !!!]

>The crucial point for the current discussion is that it doesn't
>_matter_ where the defaults come from.  The only default values in the
>DTD for schemas are also in the schema for schemas and the prose of
>the REC.

Henry argues that it doesn't matter whether they are represented in the 
schema, as long as they are represented in the prose or in the DTD. I don't 
understand this.

If the Schema for Schemas can represent defaults or fixed values, and it 
does not, then someone who looks at the Schema for Schemas does not see 
this information there. Now perhaps this information is in the DTDs, or 
buried in the text somewhere, but the reader of a document might very well 
conclude that since no defaults are specified in the schema, none are present.

What is true for the reader is infinitely more true for a program, which 
can easily find the defaults in the Schema for Schemas, but can not read 
prose and probably isn't programmed to fish out values from a DTD.

For both human readers and programs, I think there are clear advantages to 
specifying defaults and fixed values directly in the Schema for Schemas. 
Are there any clear disadvantages?

Jonathan
Received on Friday, 3 November 2000 15:12:23 GMT

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