[wg11] Re: [step-os] Using STEPMod XML Representation of EXPRESS

[Ed Barkmeyer]

David Price wrote:

> I checked the Part 28 E1 express DTD annex and there's no text at all. The
> reader must look at Part 11 to figure out what each element means. Could
> Part 28 E2 continue with that approach? If not, why not?

David Price wrote (on 7 September):

> All the work I’ve done with EXPRESS is based on the XML representation of   > EXPRESS used by STEPMod, not the Part 28 Edition 1 XML DTD. This has
> happened because the Part 28 DTD required every expression to be broken 
> into bits which seemed pointless to most people - and also meant 
> reconstructing EXPRESS from the XML using XSLT would be very difficult.

Ipse dixit.  This might be exactly why not.

> So, my question is … Are people generally comfortable with using the 
> STEPMod XML representation of EXPRESS as the de facto standard for 
> open-source STEP work? 

Note how this conveniently views "open-source STEP work" as a different 
category of effort, requiring different standards, from "in-house STEP 
work" or "proprietary product STEP work".  What is sauce for the goose 
is evidently unsuitable for the gander in the UK.  (But then British 
cooking has never been highly regarded. ;-)

> Also, I have to disagree with Ed about the free availability of
> specifications being "totally irrelevant". I expect that means we are
> talking about different things. I agree Josh's point is irrelevant with
> respect to Part 28 Edition 2 and JP-5.

My only point.

> I think Josh's point is very important with respect to the open-source
> projects and making EXPRESS/STEP more widely known. 

Absolutely.  All the competitor standards to SC4 work will appear on the 
Web, some password-protected, some free of charge.  The difference is 
that all the competitor standards will appear in their full text, with 
explanations and formal requirements.  All the "open-source projects" 
can hope to publish is the bare schemas and home-grown 'user guides' and 
'tutorials'.  OTOH, SC4 has required the useful standards to be 
unreadable compendia of overstructured stuff, and the user guides and 
tutorials are vastly more useful.

> This discussion started
> on the open-source exploder, not the WG11 exploder, and in that community
> what Josh offered to do is very valuable.

Incredible as it may seem, I thought that what Josh offered to do might 
actually be of use to an SC4 Standard *as well*.

> I do not believe the text for the Part 28 E2 standard, if it is needed, is a
> suitable replacement for the DTD user guide Josh proposed. I expect the user
> guide would more closely resemble the text in Part 11 than anything Part 28
> needs.

An interesting view:  The text that explains how to use this set of XML 
objects to convey an EXPRESS schema will be markedly different if it is 
in a technical report for the 'open-source STEP developer' community 
from what it would be in a Standard for the (unwashed?) STEP developer 
community.

Only in SC4 could such a mindset be possible:  Our standards are 
unintelligible, whereas our technical reports are lucid.  The problem, 
of course, is that this is largely valid!  ;-)  Josh's text would be a 
welcome departure.  But then David seems to think Part 11 is 
intelligible, and Martin insists that Part 21 is clear and lucid; so 
such a departure would not be so atypical for WG11.

-Ed

-- 
Edward J. Barkmeyer                        Email: edbark at nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8264                Tel: +1 301-975-3528
Gaithersburg, MD 20899-8264                FAX: +1 301-975-4694

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  and have not been reviewed by any Government authority."