Re: Ada-Singleton-Why does it work like this?

["Jeffrey R. Carter" <spam.jrcarter.not@spam.acm.org>]

patrick.gunia@googlemail.com wrote:
> Hi all,
> I�m currently working on implementing several design patterns in Ada,
> and I found some code concerning the Singleton-pattern when searching
> through the posts of this group. I used this code and it all worked as
> expected. My problem is, that I don�t ave any idea, why it does...here
> is my code:
> 
> package Singleton is
> 
> 	type Singleton_Type (<>) is tagged limited private;
> 	type Singleton_Access is access all Singleton_Type;
> 
> 	function return_Single return Singleton_Access;
> 
> 	procedure setValues(input : in out Singleton_Access; valueIN :
> Integer; valueIN2 : Integer);
> 	procedure print_something(input : Singleton_Access);
> 
> 
> 	private
> 	type Singleton_Type is tagged limited record
> 		value : Integer;
> 		value2 : Integer;
> 	end record;
> 
> end Singleton;

This is a very poor solution to the problem. A much simpler solution is

package Singleton is
    procedure Set (Value_1 : in Integer; Value_2 : in Integer);

    procedure Print;
end Singleton;

-- 
Jeff Carter
"We use a large, vibrating egg."
Annie Hall
44