RE: Runtime KLIST change?

Hans wrote:
>(Actually, lately, I've been toying with the idea of how to
>implement some form of real object-oriented programming in
>RPG without having to add any language enhancements by
>extending the approach described above.  Almost everything
>could be handled relatively easily except for the
>deallocation of object storage.)

David wrote:
>... Are you saying that
>the problem with deallocation is that there is no easy way to know when
>storage is no longer in use? If register exit or scope messages supported
>a call level, it seems like it would be much easier provide this type of
>function in RPG.

Exactly.  Say you create an object within a procedure,
and you reference the object by a pointer defined
locally.  When you leave that scope, do you deallocate
the objects storage or not?  Let's say you pass that
pointer to some other procedure that saves that pointer
in some other structure.  Deallocating the objects
storage will leave you a "dangling reference".

OK, let's say RPG had some mechanism to keep track of
object storage.  What happens if the pointer to an
object is passed to a "C" function which saves the
pointer in some other structure not under RPG's
control?  Same problem with the potential for dangling
reference.

I think this just emphasizes a point I've always
argued:  OO programming is best done using an OO
language.

Cheers!  Hans

Hans Boldt, ILE RPG Development, IBM Toronto Lab, boldt@ca.ibm.com


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