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Re: XML Schema to relaxNG xslt

• To: dareo@m... (Dare Obasanjo)
• Subject: Re: XML Schema to relaxNG xslt
• From: John Cowan <jcowan@r...>
• Date: Sat, 22 Jun 2002 18:27:54 -0400 (EDT)
• Cc: jcowan@r... (John Cowan), taylor@p... (Rick Taylor), xml-dev@l...
• In-reply-to: <8BD7226E07DDFF49AF5EF4030ACE0B7E06621D32@r...> from "Dare Obasanjo" at Jun 22, 2002 11:19:21 AM

Dare Obasanjo scripsit:

> On looking at the tutorial it seems this could be done if a RELAX NG
> implementation supported the W3C XML Schema Datatypes recommendation as
> a type library and implemented the facets as datatype parameters.

Just so:  xsd:date params { minInclusive = "1990" maxInclusive = "2000" }

> However I don't see anything that implies that an implementation with
> such functionality exists or is forthcoming. 

The Jing and Sun Multi-Schema validators both handle xSD datatypes,
so we can say that they are handled de facto if not de jure.
The schemas I write routinely assume them, and in fact the latest
version of the compact syntax quietly declares "xsd" for you.

> > but not nested  constraints. 
> 
> Thought so. 

Actually, I figured out how this could be done, although I can't
think of a clear use case for it.  But abstractly, if you have
a type "foo" that is integers >= 1 and <= 1000, thus:

foo = xsd:integer params { minInclusive = "1" maxInclusive = "1000" }

then you can declare a subtype "bar" which has an inclusive upper bound of
100 thus:

bar = foo - xsd:integer params { minExclusive = 100 }

which is read "foo's except for integers with exclusive lower bound 100".
Because the specification is inside a negation, we need to change the
maxInclusive to a minExclusive.

> > How does one restrict complex types in WXS?
> 
> A restriction of a complex type is a type that validates a subset of
> what the base type does.  

I grasp that.  Is it necessary to redeclare all the components of the
type, or only those which are changing?  And how do we say that a
component is not found in the subtype at all (maxOccurs = "0", maybe?)

> > In the spec:  
> >
> http://www.oasis-open.org/committees/relax-ng/spec-20011203.html#IDAG3YR
> >
> >Section 4.7, 3rd paragraph.
> 
> Funny enough I found the language in the spec as hard to parse as when I
> first started reading the 
> W3C XML Schema Structures recommendation less than a year ago. 

I agree: the spec is quite difficult.  It is the equivalent of
the (not yet cooked) formal model, not the schema.


-- 
John Cowan <jcowan@r...>     http://www.reutershealth.com
I amar prestar aen, han mathon ne nen,    http://www.ccil.org/~cowan
han mathon ne chae, a han noston ne 'wilith.  --Galadriel, _LOTR:FOTR_

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  • RE: XML Schema to relaxNG xslt
    • From: "Dare Obasanjo" <dareo@m...>

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