Re: [sv-ec] RE: List of Mantis item for Monday June 29th Champions Meeting

Shalom,

> Mantis 2514 was sent back to SV-EC in the May 21 Champions meeting.

I was unaware that 2514 had been rejected by the Champions, 
there is no record of that rejection in Mantis, and I don't 
recall it surfacing in an EC meeting.  We may be able to
look at it in today's meeting.

> From Francoise - no 
> Comment: It seems to me that the rule below does not support and is 
> not  consistent with class inheritance, since it says that the pure 
> constraint in the derived class is ignored and always replaced with 
> the base pure constraint. This is inconsistent with the way class 
> properties which appear in both base and derived classes work. Why?
> "A virtual class that inherits a pure constraint from its superclass
> may have a pure constraint of the same name. In this case, the pure 
> constraint in the derived virtual class shall be ignored and a 
> warning may be issued. The superclass's pure constraint shall be 
> inherited as if the duplicate in the derived class were not present."

OK.

> John - is there any difference by discarding the base version versus
> the derrived one?
> Francoise - if the body is missing, which one should the tool point to?

I agree that this would expose a difference.

> Stu - what is the rule for pure methods?
> Francoise - 8.10 - may be overridden, and no warning.

I guess Francoise was referring to this sentence in 8.20:
    Any class may be extended into an abstract
    class, and may provide additional or 
    overridden pure virtual methods.

Would everyone be OK with this rewording of the 2514
text?

REPLACE:
   A virtual class that inherits a pure constraint 
   from its superclass may have a pure constraint 
   of the same name. In this case, the pure constraint 
   in the derived virtual class shall be ignored and a 
   warning may be issued. The superclass?s pure constraint 
   shall be inherited as if the duplicate in the derived 
   class were not present.

WITH:
   A virtual class that inherits a pure constraint 
   from its superclass may have a pure constraint 
   of the same name. In this case, the pure constraint 
   in the derived virtual class shall replace the
   inherited pure constraint.

No warnings, and if the user later fails to provide an
implementation then he gets told about the prototype
in the most-derived abstract class that specified it.
-- 
Jonathan Bromley



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