How does select type extension behave?

[Phil Spiby]

Jochen,

Well done that man ;-)

You are absolutely correct.

Phil

> -----Original Message-----
> From: Jochen Haenisch [mailto:Jochen.Haenisch at epmtech.jotne.com]
> Sent: Thursday, May 16, 2002 3:39 PM
> To: 'Phil.Spiby at eurostep.com'; Pascal Huau; Module exploder; WG11
> Subject: RE: How does select type extension behave?
> 
> 
> Phil,
> 
> I think that the interfacing of wall_mounting_1 from schema_2 
> does not make
> the select items visible in schema_2. They need to be interfaced 
> explicitly.
> See 11.4.2 in the LRM:
> "When a defined data type is interfaced, the following are implicitly
> interfaced:
> - any defined data types used in the declaration of the interfaced type,
> except if the interfaced
> type is a select type; none of the selectable items are implicitly
> interfaced as a result of
> this interface;"
> 
> My understanding is:
> 	context: Schema_1
> 	attachment_method (nail, screw)
> 	 
> 	context: Schema_2
> 	attachment_method (glue, weld)
> 	permanent_attachment (glue, weld)
> 
> For the rest I agree.
> 
> Regards, Jochen.
> ____________________________________________________________
> Jochen Haenisch			E-mail: 
> Jochen.Haenisch at epmtech.jotne.com
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> 
> > -----Original Message-----
> > From:	Phil Spiby [SMTP:Phil.Spiby at eurostep.com]
> > Sent:	15. mai 2002 17:06
> > To:	Pascal Huau; Module exploder; WG11
> > Subject:	RE: How does select type extension behave?
> > 
> > Pascal,
> >  
> > My understanding is as follows:
> > context: Schema_1
> > attachment_method (nail, screw)
> >  
> > context: Schema_2
> > attachment_method (nail, screw, glue, weld)
> > permanent_attachment (nail, screw, glue, weld)
> >  
> > So in the context of schema_1, wall_mounting_1 cannot use glue, in the
> > context of schema_2, wall_mounting_1 can use glue.
> > So you are correct!
> >  
> > There is no real difference in the above results if the use is 
> changed to
> > reference.
> >  
> > Phil
> > 
> > 	-----Original Message-----
> > 	From: owner-wg11 at steptools.com [mailto:owner-wg11 at steptools.com]On
> > Behalf Of Pascal Huau
> > 	Sent: Wednesday, May 15, 2002 2:26 PM
> > 	To: Module exploder; WG11
> > 	Subject: How does select type extension behave?
> > 	
> > 	
> > 	Dear all,
> > 	 
> > 	 
> > 	a sudden doubt invades me: what is the consequence of a select type
> > extension in a multiple schemas context?
> > 	 
> > 	Let's take a slightly modified example of the DAM of P11.
> > 	 
> > 	SCHEMA schema_1;
> > 
> > 	TYPE attachment_method = EXTENSIBLE SELECT(nail, screw);
> > 
> > 	END_TYPE;
> > 
> > 	ENTITY nail;
> > 
> > 	END_ENTITY;
> > 
> > 	ENTITY screw;
> > 
> > 	END_ENTITY;
> > 
> > 	ENTITY wall_mounting_1;
> > 
> > 	mounting : product;
> > 
> > 	on : wall;
> > 
> > 	using_method : attachment_method;
> > 
> > 	END_ENTITY;
> > 
> > 	END_SCHEMA;
> > 
> > 	 
> > 
> > 	SCHEMA Schema_2;
> > 
> > 	USE FROM Schema_1(wall_mounting_1);
> > 
> > 	TYPE permanent_attachment = SELECT BASED ON attachment_method WITH
> > (glue, weld);
> > 
> > 	END_TYPE;
> > 
> > 	ENTITY glue;
> > 
> > 	END_ENTITY;
> > 
> > 	ENTITY weld;
> > 
> > 	END_ENTITY;
> > 
> > 	ENTITY wall_mounting_2;
> > 
> > 	mounting : product;
> > 
> > 	on : wall;
> > 
> > 	using_method : permanent_attachment_method;
> > 
> > 	END_ENTITY;
> > 
> > 	END_SCHEMA;
> > 
> > 	 
> > 
> > 	Initial remark: according to the DAM, if there was only one schema,
> > the attribute using_method of a valid instance of wall_mounting_1 could
> > refer to an instance of glue
> > 
> > 	Question:
> > 
> > 	- in the 2-schemas case,  can the attribute using_method of a valid
> > instance of wall_mounting_1 refer to an instance of glue?
> > 
> > 	 
> > 	My present interpretation is the following:
> > 	- there are in fact two kinds of wall_mounting_1 instances: those
> > that are created from the definition of wall_mounting_1 in schema_1 and
> > those that are created from the copy of wall_mounting_1 in schema_2
> > 	- for the first category of instances, the answer to my question is
> > NO. For the 2nd, the answer is Yes.
> > 	 
> > 	 
> > 	Will this interpretation be correct with the FDAM of Express2?
> > 	 
> > 	 
> > 	NB: I suggest to provide such a 2-schemas example of select type
> > extension in the FDAM as it corresponds to common cases of select type
> > extension in the modules.
> > 	 
> > 	 
> > 	Last (for fun):
> > 	- Is this interpretation valid if we replace USE FROM by REFERENCE
> > FROM?
> > 	 
> > 	 
> > 	Regards,
> > 	Pascal Huau
> > 	Association GOSET
> > 	107,111 avenue Clemenceau
> > 	92000 Nanterre
> > 	France
> > 
>