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=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,29fe9a340e0d180d X-Google-Attributes: gid103376,public From: bobduff@world.std.com (Robert A Duff) Subject: Re: Depending on passing mechanism Date: 1997/10/21 Message-ID: #1/1 X-Deja-AN: 284708049 References: Organization: The World Public Access UNIX, Brookline, MA Newsgroups: comp.lang.ada Date: 1997-10-21T00:00:00+00:00 List-Id: In article , Henry Baker wrote: >My paper (ftp://ftp.netcom.com/pub/hb/hbaker/LimitedRobbery.html) shows >how copy-in, copy-out semantics violates the notion of limited private >types, and is therefore a dangerous idea. I read this paper some time ago, and it was quite correct with respect to Ada 83. But in Ada 95, one can declare limited records, which are always passed by reference, and returned from functions by reference, so the programmer of the abstraction *can* solve the problem. Admittedly, the programmer can screw up, but the point is that if the programmer of the abstraction does it right, then the *clients* can't do the "limited robbery" thing pointed out in this paper. So, Henry, do you claim that that this Ada 83 problem is still present in Ada 95? I claim it's been fixed as best it could, given upward compatibility concerns. >I don't expect to change anyone's mind, but you should be aware that >Ada has serious flaws that are visible to those outside the Ada community, >although (apparently) are not visible to those within the community. Grr. *I'm* not claiming that Ada is God's gift (though some might). IMHO, Ada is a horrible programming language -- but many others (including *all* the popular ones) are far worse! ;-) When you gripe about some supposed flaw in Ada, you should make it clear what you're comparing it to -- C? C++? Common Lisp? Some obscure functional language? Some ideal language in your head? -- all of those can be valuable criticisms, but it's helpful to know whether "Ada's limited types suck" is said in relation to a language that even *has* a concept of limited types! - Bob