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=-0.9 required=5.0 tests=BAYES_00,FORGED_GMAIL_RCVD,
	FREEMAIL_FROM autolearn=no autolearn_force=no version=3.4.4
X-Google-Thread: 103376,e9c183f3911c2d73,start
X-Google-NewGroupId: yes
X-Google-Attributes: gida07f3367d7,domainid0,public,usenet
X-Google-Language: ENGLISH,ASCII-7-bit
Received: by 10.68.202.37 with SMTP id kf5mr2913503pbc.7.1334348079973;
        Fri, 13 Apr 2012 13:14:39 -0700 (PDT)
Path: 
 r9ni52693pbh.0!nntp.google.com!news1.google.com!postnews.google.com!d4g2000vbn.googlegroups.com!not-for-mail
From: Katarina Olsson <katolsster@gmail.com>
Newsgroups: comp.lang.ada
Subject: Dynamic binding
Date: Fri, 13 Apr 2012 13:13:17 -0700 (PDT)
Organization: http://groups.google.com
Message-ID: <32a3d08f-7b48-46e2-b8cf-004acb6e40a3@d4g2000vbn.googlegroups.com>
NNTP-Posting-Host: 83.250.78.146
Mime-Version: 1.0
X-Trace: posting.google.com 1334348079 18581 127.0.0.1 (13 Apr 2012 20:14:39
 GMT)
X-Complaints-To: groups-abuse@google.com
NNTP-Posting-Date: Fri, 13 Apr 2012 20:14:39 +0000 (UTC)
Complaints-To: groups-abuse@google.com
Injection-Info: d4g2000vbn.googlegroups.com; posting-host=83.250.78.146;
 posting-account=yikV-goAAACTWsgZxBw4iqS6BFfOmfrS
User-Agent: G2/1.0
X-HTTP-UserAgent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1;
 Trident/5.0; GTB7.3),gzip(gfe)
Content-Type: text/plain; charset=ISO-8859-1
Date: 2012-04-13T13:13:17-07:00
List-Id: <comp.lang.ada>

Hello,
I have a question about dispatching in Ada. As we know, methods in
java are always called on their objects. Let say that we have a class
Parent with methods a() and b(), where a calls b like this:

class Parent{

public void a() {
System.out.println("parent a");
b();
}

public void b(){
System.out.println("parent b");
}
}

Consider now the class Child extends Parent. It has overridden the b()
method like this:

class Child extends Parent{

@Override
public void b(){
System.out.println("child b");
}

}

When creating a Child object and calling the a() method,

Child c = new Child();
c.a();

the output will be the following on stdout:

>>parent a
>>child b

I have now attempted to reproduce the corresponding case in Ada. If I
create a tagged record Object in package Parent, and then the
corresponding procedures (or functions):

procedure A (This : access all Object);
procedure B (This : access all Object);

and then in package Child, I create a new Parent.Object:

type Object is new Parent.Object with null record

...and override the B method:

overrides
procedure B (This : access all Object)

This should correspond to the previous java case, shouldn't it? In any
case it seems to me that calling the A procedure on the Child Object,
would render the output

>>parent a
>>parent b -- (instead of child b)

Do I need to try again or have I understood it correctly? And if I
have, how would I best reproduce the java behaviour?