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From: "Jeffrey R. Carter" <spam.jrcarter.not@spam.not.acm.org>
Newsgroups: comp.lang.ada
Subject: Re: How to access an array using two different indexing schemes
Date: Fri, 24 Nov 2017 13:33:23 +0100
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Date: 2017-11-24T13:33:23+01:00
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On 11/24/2017 12:42 PM, Jerry wrote:
> I want to access an array such as Real_Vector (built-in for Ada >= 2005) with two different indexing schemes. For example, I would access a Real_Vector indexed (0 .. 4) when thinking of it as a times series and the same data indexed (1 .. 5) when thinking of it as a vector. Another application would be a vector indexed (-128 .. 127) because it fits my problem domain, perhaps a spatial variable, but I need to index it as (0 .. 255) when thinking of doing a Fast Fourier Transform on it.

I can't think of any situation when I'd need to access the same component of an 
array using different indices, but I note that this compiles:

procedure Renaming is
    subtype T1 is String (1 .. 5);
    subtype T2 is String (2 .. T1'Length + 1);

    S1 : T1 := "Hello";
    S2 : T2 renames S1;
begin -- Renaming
    null;
end Renaming;

-- 
Jeff Carter
"I wave my private parts at your aunties."
Monty Python & the Holy Grail
13