Part 28 support for Express v2

[Ed Barkmeyer]

David Price wrote:

> I thought the reason for writing the normative short-to-long in E2 was so
> that P28, etc. didn't have to change at all. 

I understood that the purpose of the mapping was to ensure that we didn't
have to create revision/addendum projects for every 20-series standard,
in order to accommodate EXPRESS v2.  The point Heidi made is that Part 28
v2 already is a "revision project", and since CD1 will appear in November
2003, it should make a normative reference to ISO 10303-11:2003 and not
to ISO 10303-11:1994.

Moreover, as I said in my email, EXPRESS v2 does not seem to require any
special features of Part 28 v2, except for *not mapping* attributes of
generalized data types.  The rest is just a matter of checking that the
wording works.

 > For example, what's the use of
> extensible enums/selects in an XML representation of a long form schema?

None.  In a "long form" exchange schema, the EXTENSIBLE type is no longer 
"extensible" -- whatever it has been extended to in that schema is what is
allowed in the exchange, and nothing more.

-Ed

-- 
Edward J. Barkmeyer                       Email: edbark at nist.gov
National Institute of Standards & Technology
Manufacturing Systems Integration Division
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