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Re: Layers, again (was Re: fixing (just) namespaces and validation)

• From: "Stephen T. Mohr" <smohr@v...>
• To: <xml-dev@i...>
• Date: Wed, 8 Sep 1999 09:03:00 -0400

A key sticking point is layer 4.  Until XML Schemas are a recommendation, we
have no standard way to validate XML containing namespace references.
Several proprietary or early implementation ways, yes, but none standard.
It is a shame the namespaces rec went out without going back and revising
the core XML Rec, or going forward and adding Schemas.

----- Original Message -----
From: David Megginson <david@m...>
To: <xml-dev@i...>
Sent: Wednesday, 8 September 1999 08:31 AM
Subject: Layers, again (was Re: fixing (just) namespaces and validation)


> David Carlisle writes:
>
>  > Yes, agreed, it wasn't really a criticism. The fact remains that at
>  > the current time the `problem' is that there is no standard way of
>  > getting from one layer to the other.
>
> Sure there is -- at least, the Namespaces REC defines pretty clearly
> what Namespace declarations and prefixes do.
>
>  > That is, if I have a namespace aware application that really
>  > doesn't mind what prefix is used in a document instance, there is
>  > no convenient standard way of supplying a DTD against which a set
>  > of documents to be used with that application may be validated.
>
> But that's not a problem of getting from one layer to another; it's
> simply a problem of applying an operation to a layer.  Here's one
> layered view:
>
>
> Layer 1: octets
> Validate with: (custom code)
>
> Layer 2: Unicode characters
> Validate with: (regular expression)
>
> Layer 3: XML
> Validate with: DTD
>
> Layer 4: Namespaces
> Validate with: (XML Schemas, eventually)
>
> Layer 5: RDF
> Validate with: RDF schema
>
> Layer 6: Application
> Validate with: (local business rules)
>
>
> Here's another layered view:
>
>
> Layer 1: octets
> Validate with: (custom code)
>
> Layer 2: Unicode characters
> Validate with: (regular expression)
>
> Layer 3: XML
> Validate with: DTD
>
> Layer 4: Namespaces
> Validate with: (XML Schemas, eventually)
>
> Layer 5: XHTML
> Validate with: (built-in XHTML processing rules)
>
> Layer 6: Application
> Validate with: (local business rules)
>
>
> My applications have no problem at all getting from layer 3 to layer 4
> in either example, because the path is fairly well defined; it just
> happens that there is also a convenient schema formats for applying
> structural validation or guided authoring to layer 3, but that's a
> separate operation applied to the layer, not part of the layer
> itself.  Many layers do not have a standard validation technique yet.
>
>
> All the best,
>
>
> David
>
> --
> David Megginson                 david@m...
>            http://www.megginson.com/
>
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>


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• Follow-Ups:
  • Re: Layers, again (was Re: fixing (just) namespaces and validation)
    • From: David Megginson <david@m...>

• References:
  • Re: fixing (just) namespaces and validation
    • From: David Carlisle <davidc@n...>
  • Layers, again (was Re: fixing (just) namespaces and validation)
    • From: David Megginson <david@m...>

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