From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham
	autolearn_force=no version=3.4.4
X-Google-Thread: 103376,b88383a5d9c51aa0
X-Google-Attributes: gid103376,domainid0,public,usenet
X-Google-Language: ENGLISH,ASCII
Path: 
 g2news2.google.com!news2.google.com!border1.nntp.dca.giganews.com!nntp.giganews.com!wns14feed!worldnet.att.net!attbi_s22.POSTED!53ab2750!not-for-mail
From: "Jeffrey R. Carter" <spam.jrcarter.not@spam.acm.org>
User-Agent: Thunderbird 2.0.0.21 (Windows/20090302)
MIME-Version: 1.0
Newsgroups: comp.lang.ada
Subject: Re: Ada-Singleton-Why does it work like this?
References: <5a7a870c-40e2-4803-8753-0f9cfd2b800f@k2g2000yql.googlegroups.com>
In-Reply-To: 
 <5a7a870c-40e2-4803-8753-0f9cfd2b800f@k2g2000yql.googlegroups.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 8bit
Message-ID: <WFbyl.30045$DP1.2209@attbi_s22>
NNTP-Posting-Host: 173.16.158.68
X-Complaints-To: abuse@mchsi.com
X-Trace: attbi_s22 1237927670 173.16.158.68 (Tue, 24 Mar 2009 20:47:50 GMT)
NNTP-Posting-Date: Tue, 24 Mar 2009 20:47:50 GMT
Organization: AT&T ASP.att.net
Date: Tue, 24 Mar 2009 20:47:50 GMT
Xref: g2news2.google.com comp.lang.ada:5236
Date: 2009-03-24T20:47:50+00:00
List-Id: <comp.lang.ada>

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