Final technical agreement sought for EXPRESS 2

Thu Apr 17 11:45:13 EDT 2003

David,

Over-reaction? Probably!

Having spent the last day reviewing the final draft for Express 2 I was
annoyed to see people apparently saying 
"Don't worry about that we don't need that anyway!"

The same situation occurred years ago when I had an argument with 
WG7 over constants and why they wasn't supported in P21.

My view on the short-to-long issue is that the implementers have never been
aware of the problem, the long-forms have always been created by ad-hoc
tools and never supported by the EXPRESS community. I think we have a chance
to address this problem and state quite clearly what the implications are of
the USE/REFERENCE choices made in the development of modules etc. The
short-to-long algorithm is being standardised here by the community which
has developed the language and we should maintain as much of the semantic
intent as possible in that algorithm. The implementers can just choose to
ignore the results (as I expect some will to make life easier and cheaper
for their implementations), but then it is a conscious decision to ignore
the information provided.

I don't see a major problem with USE/REFERENCE and namespace/visibility and
instantiation impacts (there are a number of minor problems though! such as
lack of chained references etc.) There are two major language design
features being addressed, resulting in two constructs being defined. There
was a problem with WG4 re-interpretation of these constructs to their own
ideas, but with the new Modules approach some of these old mis-conceptions
have vanished.

Phil

> -----Original Message-----
> From: owner-wg11 at steptools.com 
> [mailto:owner-wg11 at steptools.com] On Behalf Of David Price
> Sent: 17 April 2003 16:09
> To: wg11 at steptools.com
> Subject: RE: Final technical agreement sought for EXPRESS 2
> 
> 
> Hi Phil,
> 
> What a strange (over)reaction, I didn't actually say the 
> words you put in my mouth. 
> 
> As far as what concerns implementors, don't shoot the 
> messenger. I'm only quoting what I heard at the CAx- and 
> PDM-IFs from some of the coders. Many only want a long form, 
> sample Part 21 files, a usage guide and an AP expert to phone 
> with questions. Many don't really read the AP/module or worry 
> what the rules in the schema mean as they address so few of 
> the topic-area rules they have to worry about. That said, I'm 
> not suggesting we ignore trying to do the right thing. Just 
> that in these two cases, I support not doing anything now.
> 
> I guess I could also have explained that the reason I think 
> implementors don't worry much about use/reference and 
> visibility is that EXPRESS seems flawed in this area. 
> Visibility, namespace and partitioning are mixed up in one construct. 
> 
> On the other hand, people love derived and inverse 
> attributes, so.... go enjoy your holiday!
> 
> Cheers,
> David
> 
> Eurostep Limited
> 8 Highbury Place - Flat 5
> London N5 1QZ
> Phone 020 7704 0499
> Fax 020 7704 6249
> Mobile 07788 561 308
> 
> 
> > -----Original Message-----
> > From: owner-wg11 at steptools.com
> > [mailto:owner-wg11 at steptools.com] On Behalf Of Phil Spiby
> > Sent: 17 April 2003 15:41
> > To: 'David Price'; wg11 at steptools.com
> > Subject: RE: Final technical agreement sought for EXPRESS 2
> > 
> > 
> > David,
> > 
> > I have a problem with the approach of "lets not bother with
> > this because the current implementations don't handle it". If 
> > we are adopting this approach then perhaps we shouldn't map 
> > constants and global rules. And if the target is P21 
> > implementation then we don't need to map derived attributes 
> > or inverse attributes either since these are ignored in P21 
> > implementations.
> > 
> > With regard to comments I don't have a problem with this,
> > since it at least forces the implementers to read the couple 
> > of hundred modules documents before they start implementing!
> > 
> > Phil
> > 
> > > -----Original Message-----
> > > From: owner-wg11 at steptools.com 
> [mailto:owner-wg11 at steptools.com] On 
> > > Behalf Of David Price
> > > Sent: 17 April 2003 15:22
> > > To: wg11 at steptools.com
> > > Subject: RE: Final technical agreement sought for EXPRESS 2
> > > 
> > > 
> > > I support not mapping use/reference visibility restrictions into 
> > > global rules. I don't think implementors are worried 
> about this and 
> > > the long form is really for implementors.
> > > 
> > > I support not mapping any comments at all as mapping some 
> will lead 
> > > to confusion.
> > > 
> > > Cheers,
> > > David
> > > 
> > > Eurostep Limited
> > > 8 Highbury Place - Flat 5
> > > London N5 1QZ
> > > Phone 020 7704 0499
> > > Fax 020 7704 6249
> > > Mobile 07788 561 308
> > > 
> > > 
> > > > -----Original Message-----
> > > > From: owner-wg11 at steptools.com
> > [mailto:owner-wg11 at steptools.com] On
> > > > Behalf Of Phil Spiby
> > > > Sent: 17 April 2003 14:46
> > > > To: wg11 at steptools.com
> > > > Subject: Final technical agreement sought for EXPRESS 2
> > > > 
> > > > 
> > > > Folks,
> > > > 
> > > > There are two technical issues on the short to long form
> > generator
> > > > that, as far as I can, see there was no recorded
> > > agreement.
> > > > 
> > > > 1. Distinction of first and second class entities in the
> > longform.
> > > > This was proposed and there were discussions around how
> > to form the
> > > > required global rule(s). This is not currently in the
> > draft, but I
> > > > haven't seen where the agreement to pull it from the draft was
> > > > taken. I would prefer to see this in the document, but if 
> > there has
> > > > been agreement to remove it, or if there is no agreement
> > on how to
> > > > do it available in the next week, then I suggest we leave
> > things as
> > > > they are. Although I feel this is another opportunity to do
> > > > things correctly which has gone begging!
> > > > 
> > > > 2. Mapping of comments.
> > > > This has also been discussed and Peter pointed out that
> > since there
> > > > was no association of comments it was impossible. However, the
> > > > tagged comment capability provides an association, 
> which could be 
> > > > mapped through. I suggest we map through tagged 
> comments, and all 
> > > > other comments are dropped (as done at present).
> > > > 
> > > > Phil
> > > > 
> > > >  -----------------------------------------------------------
> > > > Dr. Phil Spiby               Tel: +44 1623 522940
> > > > Eurostep Limited             Fax: +44 1623 522940
> > > > 73 Columbia Avenue           Mobile: +44 7785 990352
> > > > Sutton-in-Ashfield           Email:Phil.Spiby at Eurostep.com
> > > > Nottinghamshire
> > > > NG17 2GZ
> > > > United Kingdom
> > > > 
> > > > 
> > > 
> > > 
> > 
> > 
> 
> 