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=-0.6 required=5.0 tests=BAYES_00,DATE_IN_PAST_24_48
	autolearn=no autolearn_force=no version=3.4.4
X-Google-Thread: a07f3367d7,26a21b9e317dc639
X-Google-Attributes: gida07f3367d7,public,usenet
X-Google-NewGroupId: yes
X-Google-Language: ENGLISH,ASCII-7-bit
Received: by 10.180.96.6 with SMTP id do6mr364557wib.1.1353553570106;
        Wed, 21 Nov 2012 19:06:10 -0800 (PST)
Path: 
 q13ni12941wii.0!nntp.google.com!feeder2.cambriumusenet.nl!feed.tweaknews.nl!85.12.40.131.MISMATCH!xlned.com!feeder3.xlned.com!news.astraweb.com!border5.a.newsrouter.astraweb.com!border2.nntp.ams.giganews.com!border3.nntp.ams.giganews.com!border1.nntp.ams.giganews.com!nntp.giganews.com!rt.uk.eu.org!de-l.enfer-du-nord.net!feeder1.enfer-du-nord.net!eternal-september.org!feeder.eternal-september.org!mx04.eternal-september.org!.POSTED!not-for-mail
From: Brian Drummond <brian@shapes.demon.co.uk>
Newsgroups: comp.lang.ada
Subject: Re: Access type to member procedure of instance (Object Oriented
 programming in Ada)
Date: Tue, 20 Nov 2012 11:43:35 +0000 (UTC)
Organization: A noiseless patient Spider
Message-ID: <k8fqd7$1hv$4@dont-email.me>
References: <9b0bcb37-8ae3-440f-af4f-a796702e4250@googlegroups.com>
	<k8d5on$t0b$1@dont-email.me>
Mime-Version: 1.0
Injection-Date: Tue, 20 Nov 2012 11:43:35 +0000 (UTC)
Injection-Info: mx04.eternal-september.org;
 posting-host="dfff62e1e537b55df42008571c03e0fe";
	logging-data="1599"; mail-complaints-to="abuse@eternal-september.org";
	posting-account="U2FsdGVkX18qxuCf3Se0jAt6ICj+7jF249Ql+dIp9A0="
User-Agent: Pan/0.139 (Sexual Chocolate; GIT bf56508
	git://git.gnome.org/pan2)
Cancel-Lock: sha1:DzFWN5FEleCFUz3hjogyV0VfIDg=
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Date: 2012-11-20T11:43:35+00:00
List-Id: <comp.lang.ada>

On Mon, 19 Nov 2012 11:39:03 +0000, Brian Drummond wrote:

> On Mon, 19 Nov 2012 01:59:42 -0800, ake.ragnar.dahlgren wrote:
> 
>> Not sure if this has already been discussed but: Is it possible to
>> define a pointer to a member procedure of an instance?
> 
> Yes.

>> Is it possible to create a parameterless access type to the
>> Message.Print procedure? The following application refuses to compile:
> 
> Message.Print is not parameterless, it is identical to Print(Message)
> so ... no.

Okay. I am astonished!
But I am more than happy to withdraw the above "no".

- Brian

--------------------------------------------------------
with Some_Package;

procedure Main is
   Message : Some_Package.Message_Type;

   procedure P renames Message.Print;

   Method_Ref : access procedure := P'access;

begin
   Message.Print;
   P;
   Method_Ref.all;
end Main;
--------------------------------------------------------

./main
Hello
Hello
Hello

And just for completeness...
--------------------------------------------------------
package Some_Package is

   type Message_Type is tagged null record;
   
   procedure Print(Message : Message_Type);

end Some_Package;
--------------------------------------------------------
with Ada.Text_IO;

package body Some_Package is

   procedure Print (Message : Message_Type) is begin
      Ada.Text_IO.Put_Line("Hello");
   end Print;

end Some_Package;
--------------------------------------------------------