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: 103376,38730e01f356adfa
X-Google-Attributes: gid103376,public
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news1.google.com!news2.google.com!news4.google.com!news2.volia.net!newsfeed.utanet.at!newsfeed.inode.at!news.hispeed.ch!linux2.krischik.com!news
From: Martin Krischik <krischik@users.sourceforge.net>
Newsgroups: comp.lang.ada
Subject: Re: types and subtypes
Date: Mon, 13 Mar 2006 20:42:06 +0100
Organization: Cablecom Newsserver
Message-ID: <1687222.lxyBhfPhPM@linux1.krischik.com>
References: <1142251677.837212.109000@i39g2000cwa.googlegroups.com>
 <bjr3vd.ep4.ln@hunter.axlog.fr>
 <1142273325.634632.41020@j52g2000cwj.googlegroups.com>
NNTP-Posting-Host: 84-74-134-212.dclient.hispeed.ch
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7Bit
X-Trace: news.hispeed.ch 1142279110 2909 84.74.134.212 (13 Mar 2006 19:45:10
 GMT)
X-Complaints-To: news@hispeed.ch
NNTP-Posting-Date: Mon, 13 Mar 2006 19:45:10 +0000 (UTC)
User-Agent: KNode/0.10.1
Xref: g2news1.google.com comp.lang.ada:3342
Date: 2006-03-13T20:42:06+01:00
List-Id: <comp.lang.ada>

ada_student@yahoo.com wrote:

> Why doesnt Ada subtyping also denote derivation as in the
> sense C++ base classes and derived classes do?

Since you know C++: subtype is more like typedef. i.E.:

class C {};

typedef C A;
typedef C B;

F1(A x);
F2(B x);

As you are experienced in C++ you will know that this won't work as both A
and B are typedefs of C and hence the same type.

Martin
-- 
mailto://krischik@users.sourceforge.net
Ada programming at: http://ada.krischik.com