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=1.3 required=5.0 tests=BAYES_00,INVALID_MSGID,
	MSGID_RANDY autolearn=no autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,8660fe29f138b478
X-Google-Attributes: gid103376,public
From: Ted Dennison <dennison@telepath.com>
Subject: Dispatching with a child for a parameter? (was: Freezing question)
Date: 1999/07/19
Message-ID: <7mvp5p$37b$1@nnrp1.deja.com>#1/1
X-Deja-AN: 502779027
References: <7mlg18$qk0$1@nnrp1.deja.com> <378E57FE.FA7EEB99@averstar.com>
 <7mnc3q$f6r$1@nnrp1.deja.com> <379347D8.A902583C@averstar.com>
X-Http-Proxy: 1.0 x37.deja.com:80 (Squid/1.1.22) for client 204.48.27.130
Organization: Deja.com - Share what you know. Learn what you don't.
X-Article-Creation-Date: Mon Jul 19 18:01:38 1999 GMT
X-MyDeja-Info: XMYDJUIDtedennison
Newsgroups: comp.lang.ada
X-Http-User-Agent: Mozilla/4.6 [en] (WinNT; I)
Date: 1999-07-19T00:00:00+00:00
List-Id: <comp.lang.ada>

In article <379347D8.A902583C@averstar.com>,
  Tucker Taft <stt@averstar.com> wrote:
> Ted Dennison wrote:
> > Ahhh. I bet that's it. Does that mean that in the example above,
Apple
> > will inherit *none* of Fruit's operations, since none of them were
> > declared before Apple?
>
> Correct.  See 7.3.1(7).


Ahhh. OK. So I'll ask the next question (with the topic appropriately
renamed:

How would one implement a hierarchy where one object has dispatching
operations that take a specific one of its chilren types as parameters?
I'm running out of ideas.

eg:

   type Widget is abstract tagged private;
   type Container is abstract new Widget with private;

   procedure Add
      (Child  : in out Widget;
       Parent : in out Container'Class
      );

Won't quite work because Add won't be inherited by any Containers unless
it is placed before the declaration of Container. But if I move it
between the two declarations, it won't compile because Container won't
have been declared yet.

--
T.E.D.


Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.