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RE: Schema for XSLT (concerns mixed content, content attribute)

From: Box, Don <dbox@develop.com>
Date: Tue, 18 Apr 2000 15:21:10 -0700
Message-ID: <824EAE80328AD311B2590090276267820AE586@mail.develop.com>
To: "'Arnold, Curt'" <Curt.Arnold@hyprotech.com>, "'xml-dev@xml.org'" <xml-dev@xml.org>
Cc: "Box, Don" <dbox@develop.com>, "'www-xml-schema-comments@w3.org'" <www-xml-schema-comments@w3.org>, "'xml-dev-temp@egroups.com'" <xml-dev-temp@egroups.com>
> -----Original Message-----
> From: Arnold, Curt [mailto:Curt.Arnold@hyprotech.com]
> Sent: Tuesday, April 18, 2000 2:01 PM
> To: 'xml-dev@xml.org'
> Cc: 'dbox@develop.com'; 'www-xml-schema-comments@w3.org';
> 'xml-dev-temp@egroups.com'
> Subject: RE: Schema for XSLT (concerns mixed content, content 
> attribute)
> 
> 
> First, a few comments on Don's schema for XSLT then a 
> discussion about some problems representing XSLT's content 
> model with schema.
> 
> The derivedBy attribute was not specified on the definition 
> of the copy and message complex types as appears to be 
> required by Schema representation constraint 1.1

Thanks. I thought I caught all of those. It's now fixed.

> The param element reference in the named-template type 
> definition should have a minOccur="0" and a 
> maxOccur="unbounded".  As written, a template has to have one 
> and only one param.

My reading of rule 4.3 under the {content type} definition (found under
section 4.3.3) implies that there is an implicit <choice minOccurs='0'
maxOccurs='unbounded' > particle over the particle children of a
content=mixed complex type.  I'll defer to Henry on this. 	

> You frequently use type-scoped element definitions.  I try to 
> avoid these unless a specific tag-name has a distinct content 
> models in different contexts since it will be difficult if 
> not impossible to
> generate an equivalent DTD.

Local element and attribute declarations are one of the more powerful
features of the schema language. I make no apologies for using them. Believe
me, the WG struggled long and hard to get them to where they are now. The
least we can do as a community is use them ;-)

> Second, Schema doesn't seem to have the ability to adequately 
> represent the content model of <xsl:template> or 
> <xsl:for-each>.  <xsl:template> content should be zero or 
> more <xsl:param> elements
> followed by template content.  

Yeah, I thought about alternative ways to model that. One way would have
been to use a named model group (that was my first pass btw). The problem is
that for mixed content, you can't use sequence constraints. This is a
problem with older technologies as well.

> <xsl:for-each> content should 
> be zero or more <xsl:sort> elements followed by template content.

Same problem.

> [snip]

I don't know that anyone has the will to add MORE complexity to the schema
language to handle mixed content. 

DB
http://www.develop.com/dbox
Received on Tuesday, 18 April 2000 18:21:11 UTC

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