Re: Normalizing array indices

[stefan-lucks@see-the.signature]

On Sat, 29 Oct 2011, Simon Wright wrote:

> Stefan.Lucks@uni-weimar.de writes:
> 
> But your problem was with A'Last, surely?

Yes. Especially, since I initially forgot about a test case with A'Last = 
Positive'Last. 

> I've had more surprises with
> 
>    type Arr is array (Integer range <>) of Float;
>    A : Arr := (1.0, 2.0, 3.0);
> 
> where A'First is Integer'First (on GNAT), ie -2**31.

That is the same ugly situation. Except that when you initialize an array 
by a constant (as in your code example above), A'First *is* the first 
element in the given range, i.e., Integer'First (in your case). In fact, 
without extra precautions (such as A: Arr(X .. X+2) := (1.0, 2.0, 3.0);), 
you may easily end up with a set of test cases where all have the property 
of A'First being Integer'First. This is very different for A'Last!

Stefan

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