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From: Ted Dennison<dennison@telepath.com>
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Subject: Iterator approach (was: List container strawman 1.3)
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Date: 2001-12-06T14:50:10+00:00
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In article <DxyP7.309$w85.20109@rwcrnsc54>, Mark Lundquist says...
>In the access discriminator way, any state of affairs that could give rise
>to a dangling iterator results in a compile-time error, and the safety comes
>at no added run-time expense.  The chained iterator approach results in a

I don't think that's true at all. Suppose I have the following (using your
example):

   type List_Ptr     is access My_Lists.List;
   type Iterator_Ptr is access My_Lists.Iterator;
   function Free is new Unchecked_Deallocation (My_Lists.List, List_Ptr);
   function Free is new Unchecked_Deallocation (My_Lists.Iterator,
Iterator_Ptr);