SEDS for ISO 10303-11

[David Price]

Jochen,

When you said it didn't apply to BAG and SET I assumed NUMBER was the only
case. The is_instance_of and is_kind_of only apply to entity instances, not
simple data types, in SDAI so it's not quite the same thing. Actually, I
think TYPEOF already works as you want in the case of entity instances. It
seems you are asking for simple types, but not aggregation types, to be
treated the same as entity instances because you believe all data values
will be represented as objects and therefore can maintain the data type of
whatever was most recently assigned. Is that right?

Sorry to be a pain but I seem to be confused as to the extent of the request
in this SEDS.
Thanks,
David

> -----Original Message-----
> From: Jochen Haenisch [mailto:Jochen.Haenisch at epmtech.jotne.com]
> Sent: 2001 November 29 13:05
> To: 'david.price at eurostep.com'
> Cc: 'WG11 exploder'; Hans Karsten Dahl
> Subject: RE: SEDS for ISO 10303-11
>
>
> Daivd,
>
> yes, I do mean that this applies to more than NUMBER! Think of an example
> with PERSON and subtypes MAN and WOMAN. That would make more sense.
> If I am not mistaken, SDAI offers the required functionality in
> is_instance_of/is_kind_of.
>
> Regards, Jochen.
>
> > -----Original Message-----
> > From:	David Price [SMTP:david.price at eurostep.com]
> > Sent:	29. november 2001 13:57
> > To:	Jochen Haenisch
> > Cc:	'WG11 exploder'; Hans Karsten Dahl
> > Subject:	RE: SEDS for ISO 10303-11
> >
> > 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
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> > > > >