Part28: schema population text from Part 21 Annex F

[Ed Barkmeyer]

Pascal Huau wrote:

> Yet, one slight issue: you repeatedly use the word "document" when you talk
> about an XML file. Could you preferably use the term "file" as:
> - sometimes, it is not clear if "document" designates a XML file or Part28
> - "file" might be clearer for a non-expert

Pascal, I don't want to make this change.  In XML, the conforming object is a "document", not a "file".  Unlike a Part 21
"exchange structure", an XML "document" can explicitly include multiple "files" (= units of data maintained by operating
systems) and XML elements from other "files" by reference. The change would be "clearer for a non-expert" only by being
inaccurate/incorrect. 

A "Part 28 document" is a "document" that conforms to Part 28 as well as the W3C XML Recommendation.  The term "document" is
used in Part 28 with the definition from the XML Recommendation -- this should be made clear in clause 3.  In some places, the
correct reference is to the "iso_10303_28 element", rather than to the "document" that contains it, but in most places it
doesn't make a difference.  (In a "pure" Part 28 document, they are the same except for the leading XML directive, but Part 28
also makes rules for iso_10303_28 elements that are included in "larger" documents.)

> Good issue against Part21 edition 2. I do think we need to consider also
> "the things the referenced instances themselves reference". 
> For example, if we reference
> an instance of circle, it would mean nothing to check the validity of the
> circle without checking the validity of the cartesian_point that defines its
> center.
> My recommendation is therefore that you update Part28, considering
> "references transitivity".

I agree, and I will do that for Part 28, as long as the acting project leader also agrees.  (I was directed by the committee to
prepare wording to match Annex F of Part 21; we are now proposing wording that does *not* match, although we believe we are
correcting an error in Part 21.)

Who will submit the SEDS against Part 21?

Thanks,
-Ed

-- 
Edward J. Barkmeyer                       Email: edbark at nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Mail Stop 8260          Tel: +1 301-975-3528
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