Re: Ada 90 inheritance request?

[bobduff@dsd.camb.inmet.com (Bob Duff)]

In article <JGOODSEN.94Dec19135859@treasure.radsoft.com>,
John Goodsen <jgoodsen@treasure.radsoft.com> wrote:
>In article <EACHUS.94Dec15184124@spectre.mitre.org> eachus@spectre.mitre.org (Robert I. Eachus) writes:
>       type Needs_Finalization is new Controlled with...;
>       -- overriding of Initialize/Adjust/Finalize
>       procedure Initialize (Obj : in out Needs_Finalization);
>       procedure Adjust     (Obj : in out Needs_Finalization);
>       procedure Finalize   (Obj : in out Needs_Finalization);
>
>       type Ctrl_T is new T with record
>	 NF:  Needs_Finalization;
>       end record;
>
>Maybe it's just me not seeing something here (which could be an indicator
>of the usability issues involved with addressing MI in Ada95), but where 
>is the polymorphic behavior in the MI lattice?  Wouldn't the above solution
>require me to delegate methods to the NF member of Ctrl_T (by hand)?

No.  When an object is finalized, all of its components are finalized
automatically.  If this weren't true, then finalization would be rather
badly broken -- any object that was a component of another object
wouldn't work right.

- Bob
-- 
Bob Duff                                bobduff@inmet.com
Oak Tree Software, Inc.
Ada 9X Mapping/Revision Team (Intermetrics, Inc.)