Re: [SPARK] Code safety and information hiding

[Maciej Sobczak <no.spam@no.spam.com>]

Bj�rn Persson wrote:

>> But I will argue that a variable which is visible everywhere in the 
>> program (in the sense that every executable piece of code can access 
>> this variable) is effectively global in that program
> 
> Exactly. And if you have:
> 
> package Pack is
>    procedure Piece_Of_Code;
> end Pack;
> 
> with Pack;
> procedure Main_Subprogram is
>    Variable : Natural;
> begin
>    Pack.Piece_Of_Code;
> end Main_Subprogram;
> 
> then Piece_Of_Code can't access Variable, so Variable isn't effectively 
> global, right?

In this case right, although going down this path one could argue that 
there are no global variables at all, because for every such variable 
there exists at least one package (like Ada.Charaters), that cannot 
access it. :-)


-- 
Maciej Sobczak : http://www.msobczak.com/
Programming    : http://www.msobczak.com/prog/