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From: lutz@iks-jena.de (Lutz Donnerhacke)
Newsgroups: comp.lang.ada
Subject: Re: Container reqs
Date: Thu, 18 Oct 2001 20:09:15 +0000 (UTC)
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* Jeffrey Carter wrote:
>> Lutz Donnerhacke wrote:
>>> Multiple tasks modifying the same data structure simultanously is a
>>> common requirement for any larger application.
>
>Modifying an ordered structure such as a tree while iterating seems like a
>recipe for disaster, even from a single thread.

But it is a very common problem. Normally databases are involved to solve
this problem on larger collections.

>By "ordered" I mean a structure where the position of an Element within
>the structure is determined by the value of the Element. What is the next
>Element in the structure if the current Element has moved?

Wrong preconditions. You talk about arrays, but even those needs not to be
counted continously. Example:
  type offset is (one, two, four, five);
  for offset use (one => 1, two => 2, four => 4, five => 5);
  type example is array (offset) of Item;