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From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Re: List container strawman
Date: 03 Nov 2001 08:09:40 +0000
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Date: 2001-11-03T08:09:40+00:00
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Ted Dennison<dennison@telepath.com> writes:

> In article <mailman.1004730907.14961.comp.lang.ada@ada.eu.org>, Mike Brenner
> says...
> >
> >Comment 3. There is no method of putting in a garbage collector.
> 
> *That's* the other thing I forgot! I was thinking of having a
> storage pool be an optional parameter (the default being the default
> storage pool). Any problems with that?

I couldn't find a way of giving the parameter a default; the problem
being that there's no standard way of getting at the standard storage
pool. GNAT makes it visible, but warns you about using features that
aren't "officially" supported.

I guess one could go in for indirections using accesses or functions
.. I have

  generic
     Storage : in out System.Storage_Pools.Root_Storage_Pool'Class;
  package BC.Containers.Collections.Unbounded is

and you can get at the default pool using

  with System.Storage_Pools;

  package BC.Support.Standard_Storage is

     type T is access Integer; -- arbitrary subtype

     Pool : System.Storage_Pools.Root_Storage_Pool'Class
       renames T'Storage_Pool;

  end BC.Support.Standard_Storage;


Aha! this compiles (GNAT 3.14a1), whether it is legal and works on
other compilers is a different matter of course ..

  with System.Storage_Pools;
  package Default_Pool is

     type Pool_Access
     is access all System.Storage_Pools.Root_Storage_Pool'Class;

     type T is access Integer;
     Pool : System.Storage_Pools.Root_Storage_Pool'Class
       renames T'Storage_Pool;

     generic
	Storage : Pool_Access := Pool'Access;
     package G is
     end G;

  end Default_Pool;