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From: "Randy Brukardt" <randy@rrsoftware.com>
Newsgroups: comp.lang.ada
Subject: Re: How to access an array using two different indexing schemes
Date: Thu, 30 Nov 2017 16:10:21 -0600
Organization: JSA Research & Innovation
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Xref: reader02.eternal-september.org comp.lang.ada:49284
Date: 2017-11-30T16:10:21-06:00
List-Id: <comp.lang.ada>

"Shark8" <onewingedshark@gmail.com> wrote in message 
news:ed357f21-d318-4768-a756-b86e9532a1ae@googlegroups.com...
>On Thursday, November 30, 2017 at 12:31:53 PM UTC-7, G. B. wrote:
>> AdaMagica wrote:
>> > Am Donnerstag, 30. November 2017 15:47:40 UTC+1 schrieb Niklas Holsti:
>> >> Perhaps the next Ada revision could extend 4.6(5/2) to include a type
>> >> conversion in a renaming, as a view conversion?
>> >
>> > I sent this request to Ada Comment.
>> >
>>
>> Isn't a type conversion potentially copying?
>
>Perhaps, but a renaming [of extant data] shouldn't be... Especially in this
>particular case since we have bounds-sliding anyways.

This particular case is safe, but it is not safe if the type conversion does 
any sort of representation change. (In that case, the representation change 
would be hidden from the uses, which Ada has never wanted to do.) Not sure 
how to reconcile that. In any case, parameter passing does work for the OPs 
problem (as I showed), so there is a solution, even if it is a bit clunky.

                                 Randy.



What is wanted here is a View Conversion, not really a Type Conversion.