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

[Mason, Howard (UK)]

I think that there is scope here for an informed debate on exploiting the SC4 information models in the broader XML/UML environment. 

A clear priority is to have an agreed XML representation of our models that can be broadly used.  This is a baseline capability which can be enhanced by other features to exploit XML technologies.

I also think there is a market for open source implementation tools to promote this work, linked into the rapidly evolving technologies for information transmission.  Such tools could be driven from the STEPmod repository, which is also used to generate the ISO standards.  By the way, much of the content of ISO standards is prescribed by international agreement - the rest is imposed by ourselves - SC4 is "us" not "them".

The issue of free availability is separate - we are suffering from having 11179 being promoted by JTC1 because it is free.

I also assume that Ed has not eaten in the UK recently, since there has been a significant change in UK restaurant culture.  It is possible to get food of dubious quality in the US, also!

I look forward to discussions in Seattle, between WG11 and the Industrial Data on teh Web group.

Howard Mason

-----Original Message-----
From: wg11-bounces at steptools.com [mailto:wg11-bounces at steptools.com]On
Behalf Of Ed Barkmeyer
Sent: 08 September 2004 20:20
To: STEP Open-Source
Cc: 'SC4 WG11'
Subject: Re: [wg11] Re: [step-os] Using STEPMod XML Representation of
EXPRESS


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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

"The opinions expressed above do not reflect consensus of NIST,
  and have not been reviewed by any Government authority."
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