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From: Jeffrey Carter <spam.jrcarter.not@spam.not.acm.org>
Newsgroups: comp.lang.ada
Subject: Re: asynchronous task communication
Date: Tue, 08 Jan 2013 14:01:51 -0700
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Date: 2013-01-08T14:01:51-07:00
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On 01/08/2013 11:18 AM, Simon Wright wrote:
> Jeffrey Carter <spam.jrcarter.not@spam.not.acm.org> writes:
>
>> If you have an item in your (unbounded) array, indexed by Positive, at
>> index 3, it will still be at index 3 if you assign to components at
>> other indices, or extend the array by adding new components beyond the
>> current end of the array. However, if you insert a new component
>> before the existing item at index 3, then all the components after the
>> new component will shift up, and the existing item will then be at
>> index 4.
>>
>> One would think that a Cursor would behave similarly.
>
> Not so! The Cursor becomes ambiguous[1], and using it is a bounded
> error. GNAT GPL 2012 implements Cursor using an Index, & behaves the way
> you'd expect.

To my mind, that is Cursor behaving similarly. Just as the index 3 is no longer 
the index of the item in question, so the Cursor should not be relied on.

-- 
Jeff Carter
"Whatever it is, I'm against it."
Horse Feathers
46