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Re: UPA and schema handling

• To: Bob Foster <bob@o...>
• Subject: Re: UPA and schema handling
• From: Ian Graham <ian.graham@u...>
• Date: Sun, 17 Oct 2004 21:45:02 -0400
• Cc: xml-dev@l...
• In-reply-to: <4173151B.90700@o...>
• References: <41729D89.6020906@u...> <4172BD45.7040409@o...> <4172F10A.1070002@u...> <4173151B.90700@o...>
• User-agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.2) Gecko/20040803

Have a look at XML spy 2004's FAQ:

http://www.xmlspy.com/support_faq_ide_schema.html#q6_schema

It says in part:

    In our opinion the detection of a non-deterministic model
    as an error in a DTD or Schema would be wrong, and we will
    not implement this.

Sounds to me as if they're ignoring a normative portion of the spec, and 
don't consider this a bug....

Bob Foster wrote:

> I don't think the problem is people ignoring parts they don't like. The 
> spec isn't easy to understand or to implement and there is no concept of 
> certification. Anyone can claim to process XML Schema regardless of the 
> actual coverage of their implementation. (In fact, the existence of 
> several partially conformant "implementations" is an important milestone 
> in obtaining Recommendation status for the spec.) In such an 
> environment, people ship what they can get away with and work the bug 
> list over time.
> 
> Bob
> 
> Ian Graham wrote:
>  > Seems unfortunate that vendors can just ignore normative portions of a
>  > spec. I can understand differences in implementation where the spec is
>  > complex, or unclear. But ignoring parts you don't like is simply goofy.
>  > To reuse your phrase, I would have to call that "bad art" rather than
>  > "state of the art" ;-/
>  >
>  > Best --
>  > Ian
>  > Bob Foster wrote:
>  >
>  >> Unique particle attribution is normative and not optional, but not all
>  >> processors check it correctly and some processors check it optionally.
>  >> Of course that leads to interoperability errors, and not just around
>  >> UPA, but that's the state of the art.
>  >>
>  >> Bob Foster
>  >> http://xmlbuddy.com/
>  >>
>  >> Ian Graham wrote:
>  >>  > I've been fiddling around with very simple schemas that violate the
>  >> UPA
>  >>  > constraint -- and have found that some schema tools flag UPA errors
>  >>  > (e.g. oXygen), while others (e.g. XML spy) do not. This 
> inconsistency
>  >>  > is, at best, confusing -- but at worst would seem to lead to
>  >>  > interoperability problems, since a designer could build a schema 
> with
>  >>  > one toolset and find it is not acceptable to another.
>  >>  >
>  >>  > So am I missing something here?  Is UPA really an inviolable
>  >> constraint
>  >>  > [my interpretation], or is it just a guideline, in the manner of
>  >>  > Appendix E 'Deterministic Content Models (Non-Normative)' in the
>  >> XML 1.0
>  >>  > specification?  And if it's just a guideline, would this not lead to
>  >>  > interoperability problems as I've just outlined?
>  >>  >
>  >>  > And, if someone already went down this rat hole, can anyone refer
>  >> me to
>  >>  > the corresponding xml-dev (or other) thread ;-)
>  >>  >
>  >>  > Best --
>  >>  >
>  >>  > Ian
>  >>
>  >>
>  >
> 
> 

-- 
Ian Graham
H: 416.769.2422 / W: 416.513.5656 / E: <ian . graham AT utoronto . ca>

• Follow-Ups:
  • Re: UPA and schema handling
    • From: ht@i... (Henry S. Thompson)
  • RE: UPA and schema handling
    • From: "Michael Kay" <michael.h.kay@n...>

• References:
  • UPA and schema handling
    • From: Ian Graham <ian.graham@u...>
  • Re: UPA and schema handling
    • From: Bob Foster <bob@o...>
  • Re: UPA and schema handling
    • From: Ian Graham <ian.graham@u...>
  • Re: UPA and schema handling
    • From: Bob Foster <bob@o...>

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