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=-2.9 required=5.0 tests=BAYES_00,MAILING_LIST_MULTI autolearn=unavailable autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,a00006d3c4735d70 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2004-01-26 11:31:21 PST Path: archiver1.google.com!news2.google.com!news.maxwell.syr.edu!newsfeed.icl.net!newsfeed.fjserv.net!proxad.net!usenet-fr.net!enst.fr!melchior!cuivre.fr.eu.org!melchior.frmug.org!not-for-mail From: "Alexandre E. Kopilovitch" Newsgroups: comp.lang.ada Subject: Re: In-Out Parameters for functions Date: Mon, 26 Jan 2004 22:00:58 +0300 (MSK) Organization: Cuivre, Argent, Or Message-ID: References: <5ad0dd8a.0401260606.76cc4415@posting.google.com> NNTP-Posting-Host: lovelace.ada-france.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: melchior.cuivre.fr.eu.org 1075143772 20185 80.67.180.195 (26 Jan 2004 19:02:52 GMT) X-Complaints-To: usenet@melchior.cuivre.fr.eu.org NNTP-Posting-Date: Mon, 26 Jan 2004 19:02:52 +0000 (UTC) To: comp.lang.ada@ada-france.org Return-Path: In-Reply-To: <5ad0dd8a.0401260606.76cc4415@posting.google.com>; from Wojtek Narczynski at 26 Jan 2004 06:06:08 -0800 X-Mailer: Mail/@ [v2.44 MSDOS] X-Virus-Scanned: by amavisd-new-20030616-p5 (Debian) at ada-france.org X-BeenThere: comp.lang.ada@ada-france.org X-Mailman-Version: 2.1.3 Precedence: list List-Id: Gateway to the comp.lang.ada Usenet newsgroup List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Xref: archiver1.google.com comp.lang.ada:4833 Date: 2004-01-26T22:00:58+03:00 Wojtek Narczynski wrote: > > The F and G functions may both update global variable X, but neither of them > > uses that X for computing the result, and this is what makes difference. > > Oh, I can easily imagine functions H and J that both do read > _and_write_ a global variable Y. And use this global variable Y for computing their results? If you really can easily imagine all that mess for professional Ada programmers then perhaps you must be sent back to undergraduate courses -;) . Note that there are fully legitimate and safe cases where functions actually read and write global variables, but *not use those variables for computing thier results*. (I think that in majority of reasonable cases where several functions use the same global variable both for reading and writing, that global variable is an array). > Perhaps just expressions with value (and side effect) dependent on the > order of computation, should not be allowed. It would be a good rule, > but it is too late for it, I guess. You are in hurry? You expect end of the world? -:) Well, I think that you'll be able to formulate some good *exact and complete* rule of this kind not earlier than the ARG will call for proposals for Ada1Z -;) . Alexander Kopilovitch aek@vib.usr.pu.ru Saint-Petersburg Russia