using `use' : what is the best practice ?

[milouz <a.michelizza@gmail.com>]

Hi guys,
Sorry with my annoying questions, but it's not easy to program in Ada
after 20 years programming in asm / C ;-)

Maybe a not so anecdotic question : when using the 'use' clause ?

My first thought is that using 'use' is not good because it masks the
package tree.
For example, if I have 2 packages with procedures sharing the same
name, example `P1.Foo' and `P2.Foo', my code won't be very readable if
I only write the short name (`Foo') :

   with P1; use P1;
   with P2; use P2;

   procedure Main is
      My_Val : Integer;
   begin
      Foo(My_Val);  -- P1 or P2 ?
   ...

But always avoiding 'use' give some rather obfuscated code, especially
when using some specific arithmetic operator. For example, playing
with Address arithmetic without 'use' :

   with System;
   with System.Storage_Elements;

   procedure Main is
      A : System.Address;
      N : Integer;
   begin
      A := System.Storage_Elements.To_Address(16#10000#);
      N := 4;
 
System.Storage_Elements."+"(System.Storage_Elements.Storage_Offset(N),
A);
   end Main;

The same code with 'use' is more readable :

   with System; use System;
   with System.Storage_Elements; use System.Storage_Elements;

   procedure Main is
      A : Address;
      N : Integer;
   begin
      A := To_Address(16#10000#);
      N := 4;
      A := A + Storage_Offset(N);
   end Main;

As I'm very new, I'd like to have your opinion about the way to use
'use'.