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

[Jerry <list_email@icloud.com>]

On Friday, November 24, 2017 at 5:33:25 AM UTC-7, Jeffrey R. Carter wrote:
> 
> 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;

This doesn't seem to solve the "duplicate indexing" need. I think my remark here restates AdaMagica's remark nearby.

with Ada.Text_IO; use Ada.Text_IO;

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
    Put_Line("S1");
    for i in S1'range loop
         Put(i'img & " "); Put(S1(i)); New_Line;
    end loop;
    New_Line;
 
    Put_Line("S2");
    for i in S2'range loop
         Put(i'img & " "); Put(S2(i)); New_Line;
    end loop;
    New_Line;
end Renaming;

This outputs

S1
 1 H
 2 e
 3 l
 4 l
 5 o

S2
 1 H
 2 e
 3 l
 4 l
 5 o

But a question: Is memory allocated for S2?

Jerry