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: 103376,9d303864ae4c70ad X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2004-04-08 10:37:13 PST Path: archiver1.google.com!news1.google.com!news.glorb.com!news.agarik.com!news.agarik.com!usenet-fr.net!enst.fr!melchior!cuivre.fr.eu.org!melchior.frmug.org!not-for-mail From: "Alexander E. Kopilovich" Newsgroups: comp.lang.ada Subject: Re: Reprise: 'in out' parameters for functions Date: Thu, 8 Apr 2004 21:19:36 +0400 (MSD) Organization: Cuivre, Argent, Or Message-ID: References: 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 1081445467 10614 212.85.156.195 (8 Apr 2004 17:31:07 GMT) X-Complaints-To: usenet@melchior.cuivre.fr.eu.org NNTP-Posting-Date: Thu, 8 Apr 2004 17:31:07 +0000 (UTC) To: comp.lang.ada@ada-france.org Return-Path: In-Reply-To: ; from Stephen Leake at 07 Apr 2004 22:21:08 -0400 X-Mailer: Mail/@ [v2.44 MSDOS] X-Virus-Scanned: by amavisd-new-20030616-p7 (Debian) at ada-france.org X-BeenThere: comp.lang.ada@ada-france.org X-Mailman-Version: 2.1.4 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:6857 Date: 2004-04-08T21:19:36+04:00 Stephen Leake wrote: > > > This is what I wanted to declare: > > > > > > function Parse > > > (Error_Label : in String; > > > Token : in out Token_List.List_Iterator) > > > return String; > > > -- Process Token, which should contain '([Config_File =>] )'. > > > -- Return the string. > > > -- Delete parsed tokens from Token. > > > > > One thing is missing in this your explanation: why exactly you don't want to > > make that List_Iterator global (instead of passing it as IN OUT argument) ? > My answer is "I never make anything global unless it has to be, > because that usually leads to trouble". Yes, but this is general attitude, and it says nothing definite about particular case - it can be that detailed analysis of this particular case will show reasons to make it global. > In this case, Token is actually the contents of an aggregate, part of > a larger statement that is dynamically allocated. It must be modified > in place; copying it to a global to pass it to this routine would be a > maintenance nightmare. I did not think about copying. I think that real question may be whether Parse conceptually deals with Token_List.List_Iterator or with the whole List_Iterator. In the latter case a global is generally possible without any copying. > And no, I don't consider "Ada doesn't allow 'in out' in functions" a > good reason to make something global; I'll change it to a procedure > first. Certainly. But there may be other reasons (originated from detailed design). Alexander Kopilovich aek@vib.usr.pu.ru Saint-Petersburg Russia