Re: How to access an array using two different indexing schemes

[Jerry <list_email@icloud.com>]

On Sunday, November 26, 2017 at 1:58:32 AM UTC-7, Dmitry A. Kazakov wrote:
> On 2017-11-26 02:07, Jerry wrote:
> > On Friday, November 24, 2017 at 4:38:10 PM UTC-7, Jerry wrote:
> >> I frequently allocate memory for arrays from the heap, as discussed previously on this list, like this:
> >>
> >> with Ada.Numerics.Long_Real_Arrays; use Ada.Numerics.Long_Real_Arrays;
> >> procedure Double_Array_2 is
> >>      type Real_Vector_Access is access Real_Vector;
> >>      x_Ptr : Real_Vector_Access := new Real_Vector(-4 .. 3);
> >>          x : Real_Vector renames x_Ptr.all;
> >>      y_Ptr : Real_Vector_Access := new Real_Vector(0 .. 7);
> >>          y : Real_Vector renames y_Ptr.all;
> >> begin
> >>      null;
> >> end Double_Array_2;
> >>
> >> How would I use the 'Address trick in this situation?
> >>
> > Any help here? I've spend several hours on this one. I'm not out of
> > ideas but I'm pretty challenged by this. Currently trying things with
> > System.Address_To_Access_Conversions.
> 
> Where is a problem?
> 
> with Ada.Numerics.Long_Real_Arrays; use Ada.Numerics.Long_Real_Arrays;
> procedure Double_Array_2 is
>     type Real_Vector_Access is access Real_Vector;
>     x_Ptr : Real_Vector_Access := new Real_Vector(-4 .. 3);
>     x : Real_Vector renames x_Ptr.all;
>     y : Real_Vector(0..7);
>     for y'Address use x'Address;
> begin
>     null;
> end Double_Array_2;
> 
> -- 
> Regards,
> Dmitry A. Kazakov
> http://www.dmitry-kazakov.de

Thanks, Dmitry. I kept trying to use a pointer for y. I anticipated that I would feel like an idiot when someone showed me how to do this and I was right.

Jerry