SEDS for ISO 10303-11

[David Price]

Hi Jochen,

My two kroner...

I do agree NUMBER is a strange datatype but I'm not sure that means the
relationship between it and a specialiation of it should be treated
differently OR do you mean for this to apply to more than NUMBER?

> An implementation will nontheless keep track of the actual type of an
> object. So, why not give the user the (necessary) possibility to
> query this?

I'm not sure it's a good idea to assume this for all implementations.
Functionally, NUMBER is treated like REAL in many of the 20s series parts so
implementations may lose the distinction. However, I've not implemented this
myself so will leave that issue to others.

Cheers,
David

> -----Original Message-----
> From: Jochen Haenisch [mailto:Jochen.Haenisch at epmtech.jotne.com]
> Sent: 2001 November 29 12:24
> To: 'david.price at eurostep.com'
> Cc: 'WG11 exploder'; Hans Karsten Dahl
> Subject: RE: SEDS for ISO 10303-11
>
>
> David,
>
> no, the point is not to detect that a BAG is a SET based on the
> characteristics of its population. This is beyond the limits, but not very
> much. The point is to have a possibility to query which type of value has
> intentionally been assigned to a parameter.
>
> Building on the previous example one could imagine the following
> situation:
>
>  LOCAL
>    x : NUMBER;
>    y: REAL := 1.0;
>    z: INTEGER := 2;
>  END_LOCAL;
>
>  IF (...) THEN x:=y;
>  ELSE x:=z;
>  END_IF;
>
>  IF ('REAL' IN TYPEOF(x)) THEN ...; END_IF;
>
> Even though this may not be the most convincing real life example, I hope
> you see the usefulness of TYPEOF returning the type of the value that has
> been assigned to it. How else could one treat x differently based on the
> type that it is carrying around?
> An implementation will nontheless keep track of the actual type of an
> object. So, why not give the user the (necessary) possibility to
> query this?
>
> Best regards, Jochen.
>
> > -----Original Message-----
> > From:	David Price [SMTP:david.price at eurostep.com]
> > Sent:	29. november 2001 12:13
> > To:	Jochen Haenisch
> > Cc:	'WG11 exploder'
> > Subject:	RE: SEDS for ISO 10303-11
> >
> > Jochen,
> >
> > I'm not sure I like the idea that the datatype of something
> depends on its
> > instantiated value. TYPEOF is a datatype, not data value,
> function so I'm
> > a
> > bit confused. Can you elaborate on why you want this change? Is this
> > example
> > any different from x being declared as a BAG that happens to be
> > instantiated
> > with non-duplicate members and so you want TYPEOF to return SET?
> >
> > Hope my question makes sense. It's basically, how far would you expect
> > this
> > proposal to go?
> >
> > Cheers,
> > David
> >
> > > -----Original Message-----
> > > From: owner-wg11 at steptools.com [mailto:owner-wg11 at steptools.com]On
> > > Behalf Of Jochen Haenisch
> > > Sent: 2001 November 29 09:02
> > > To: 'seds at cme.nist.gov'
> > > Cc: 'WG11 exploder'
> > > Subject: SEDS for ISO 10303-11
> > >
> > >
> > > Please, consider the SEDS report that is included below.
> > > Best regards, Jochen Haenisch.
> > >
> > >  <<SEDS_Express_20011129.txt>>
> > >
> > > ____________________________________________________________
> > > Jochen Haenisch			E-mail:
> > > Jochen.Haenisch at epmtech.jotne.com
> > > EPM Technology AS		Home of the EXPRESS Data Manager
> > > P.O Box 6629 Etterstad		Tel: Int + 47 23 17 17 26
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> > >
> > >