Re: Normalizing array indices

[Simon Wright <simon@pushface.org>]

Stefan.Lucks@uni-weimar.de writes:

> In many cases, array ranges starting with an arbitrary index are
> better (higher level) to model an application's demands. But
> sometimes, like when applying a sorting routine, this extra
> information is actually some ballast.
>
> Ideally, the specification of a subprogram would carry the information 
> that the subprogram only uses "normalized" array indices, to free the 
> tester from having to consider test cases with different A'First:
>
>   procedure Sort(A: in out Sort_Array_Type(1 .. <>)); 
>
> The user can still call Sort with any array of range, say, 4711 .. 9421, 
> but Sort coldn't tell that apart from an array of range 1 .. 4711. Thus, 
> there is no reason for additional test cases with different values 
> for A'First. 

But your problem was with A'Last, surely?

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.