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From: randhol+abuse@pvv.org (Preben Randhol)
Newsgroups: comp.lang.ada
Subject: Re: Question about Finalization Control and reference counting
Date: Thu, 26 Apr 2001 08:50:17 +0000 (UTC)
Organization: Norwegian university of science and technology
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On Wed, 25 Apr 2001 22:22:15 GMT, Jeffrey Carter wrote:
> 
> Perhaps I'm trying to be too user friendly. Or maybe I'm failing. For a
> real list component, Node would not be controlled, but the list type
> would.
> 
> A list component will generally not make its access type visible to its
> clients. All modification of a list will be through the operations
> provided, so freeing space when a node is deleted can be handled
> properly through those operations. You would rather want to define
> Adjust and Finalize for an entire List, to ensure that memory is managed
> properly.

Yes :-) After thinking a bit yesterday I did exactly this :-). Made the
Node types all private and added an itterator to the List so I can do:

Goto_First (List); Goto_Next (List); Goto_Previous (List); Goto_Last (List);

etc... (Prepending Goto so I don't mess with possible variable name space.)

and then I have : Get_Element (List) return Data_Type; which gives the
Data_Type (not the access value) in the Node the itterator is pointing
at at the moment.

As the Data_Type is generic it will then be up to the user to apply
Finaliaztion control on the Data_Type and then everything is ok if I
remove a Node.

Now I'll add Finalization to the List object :-)


Thanks everybody for much valued help!

-- 
Preben Randhol ------------------- http://www.pvv.org/~randhol/ --
                 �For me, Ada95 puts back the joy in programming.�