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From: Ludovic Brenta <ludovic@ludovic-brenta.org>
Newsgroups: comp.lang.ada
Subject: Re: generic question
References: <1163959439.299036.129940@e3g2000cwe.googlegroups.com>
Date: Sun, 19 Nov 2006 20:17:20 +0100
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Date: 2006-11-19T20:17:20+01:00
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markww writes:
>     type NODE_REC is
>         record
>             unknown_data_type : generic;  -- not sure how to express
> this in ada
>             Next_Node : NODE_REC_PTR;
>             Prev_Node : NODE_REC_PTR;
>       end record;

generic
   type T is private;
package P is
   type Node;
   type Node_Ptr is access Node;
   type Node is record
      Data : T;
      Prev, Next : Node_Ptr;
   end record;
end P;

HTH

See also the predefined containers, in particular
Ada.Containers.Doubly_Linked_Lists [1]

[1] http://www.adaic.com/standards/05rm/html/RM-A-18-3.html

-- 
Ludovic Brenta.