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From: Richard D Riehle <laoXhai@ix.netcom.com>
Subject: Re: Inheritance and Polymorphism in Ada !!
Date: 1999/10/23
Message-ID: <7uqvb1$2m4$1@nntp3.atl.mindspring.net>#1/1
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References: <7u64k3$l1d$1@hiline.shinbiro.com> <3806DC34.1513E8B1@frqnet.de>
 <7u7o36$tv8$1@nntp6.atl.mindspring.net> <38077b65_1@news1.prserv.net>
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Organization: MindSpring Enterprises
X-Server-Date: 23 Oct 1999 00:26:09 GMT
Newsgroups: comp.lang.ada
Date: 1999-10-23T00:26:09+00:00
List-Id: <comp.lang.ada>

>In article <38077b65_1@news1.prserv.net>,
>  "Matthew Heaney" <matthew_heaney@acm.org> wrote:
>> The purpose of a declare block is to localize the declaration
>> of objects, as your example illustrated.

I remembered reading a short discussion of the Algol
equivalent of declare blocks in Dijkstra's oldie but goodie, 
A Discipline of Computer Programming.  So I pulled my
dog-eared copy from a nearby bookshelf to re-read it.
Read chapter 10 for a well-reasoned criticism of this notion.  

Not very much has changed in the Ada declare block.  All the 
same problems exist that we had with Algol. It is quite 
wonderful that we are still arguing the same issues that we 
were arguing about in 1976 when Dijkstra's book was published.

Richard Riehle
http://www.adaworks.com