Re: Returning ranges from a function (was: How to loop (elegant) throug a vector ?)

[Maciej Sobczak <see.my.homepage@gmail.com>]

On 23 Cze, 11:47, Stefan Bellon <bel...@software-erosion.org> wrote:

> > What about "independent addressability" from 13.3?

> I don't think this applies here as the array components are not aliased

With my version of GNAT everything is stored at the same location when
"aliased" is added to components of the array.
I can see it by having *equal* access variables created from different
array indices:

with Ada.Text_IO;

procedure A is

   type Empty_Record is null record;
   for Empty_Record'Size use 0;

   A : array (Integer range <>) of aliased Empty_Record := (1 .. 100
=> <>);

   type Empty_Ptr is access all Empty_Record;
   P1 : Empty_Ptr := A (1)'Access;
   P2 : Empty_Ptr := A (2)'Access;

begin

   if P1 = P2 then
      Ada.Text_IO.Put_Line ("Equal access values.");
   else
      Ada.Text_IO.Put_Line ("Distinct access values.");
   end if;

end;

Is it bug or feature?

> But in any case my "range objects" do not rely on the compiler not
> allocating memory.

Right, but they just expose an interesting compiler behavior.

--
Maciej Sobczak * www.msobczak.com * www.inspirel.com