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,FREEMAIL_FROM autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,436e4ce138981b82 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2004-03-11 09:26:44 PST Path: archiver1.google.com!news2.google.com!news.maxwell.syr.edu!newspeer.radix.net!uunet!ash.uu.net!spool.news.uu.net!not-for-mail Date: Thu, 11 Mar 2004 12:26:28 -0500 From: Hyman Rosen User-Agent: Mozilla Thunderbird 0.5 (Windows/20040207) X-Accept-Language: en-us, en MIME-Version: 1.0 Newsgroups: comp.lang.ada Subject: Re: abstract sub programs overriding References: <1078839257.157439@master.nyc.kbcfp.com> <5cmr40t76va200betf07b7bd6er05ltto9@4ax.com> <1078845298.702789@master.nyc.kbcfp.com> <0ipr40thtf86b520a0qdi003aj87gtuhd4@4ax.com> <1078849973.701176@master.nyc.kbcfp.com> <1078924150.268074@master.nyc.kbcfp.com> <1079014276.527406@master.nyc.kbcfp.com> <67u0505uu3gfmlt8p28e9jkaco0nljquut@4ax.com> <1079019616.621636@master.nyc.kbcfp.com> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Organization: KBC Financial Products Message-ID: <1079026002.840030@master.nyc.kbcfp.com> Cache-Post-Path: master.nyc.kbcfp.com!unknown@aphelion.nyc.kbcfp.com X-Cache: nntpcache 3.0.1 (see http://www.nntpcache.org/) NNTP-Posting-Host: 204.253.250.10 X-Trace: 1079026002 9344 204.253.250.10 Xref: archiver1.google.com comp.lang.ada:6247 Date: 2004-03-11T12:26:28-05:00 List-Id: Dmitry A. Kazakov wrote: > If that would be true, no C++ library would have Init() in each and > other class. As you might already suspect, there is no paucity of poorly designed C++ code, OO and otherwise. There is also a good deal of C++ that was written for exception handling disabled, and used Init methods as a way of detecting failure of construction. > But they cannot do it, when dispaching methods need to be called as a > part of base specific object construction. Correct. This makes the chicken-and-egg problem visible to the programmer, who must then code a workaround. This is C++ helping, not hindering. > It quite obvious: "To invoke a service from a derived type" is a more > complicated way to say "to dispatch". But dispatching is possible on > class-wide objects only. But the distinction between classwide objects and non-classwide objects exists only in your universe. In Ada you can always view-convert an object into its classwide type.