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=0.2 required=5.0 tests=BAYES_00,INVALID_MSGID, REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,203d1f2317947ef5 X-Google-Attributes: gid103376,public From: rogoff@sccm.Stanford.EDU (Brian Rogoff) Subject: Re: others clause Date: 1996/09/02 Message-ID: #1/1 X-Deja-AN: 178019474 references: <3227AAA6.67C9@ghgcorp.com> organization: /u/rogoff/.organization reply-to: rogoff@sccm.stanford.edu newsgroups: comp.lang.ada Date: 1996-09-02T00:00:00+00:00 List-Id: geert@fozzie.sun3.iaf.nl (Geert Bosch) writes: Actually, one of the big dangers of object-oriented programming is that assumptions that hold for a base class do not necessarily hold for derived classes. Too many people think that OOP easily scales to large projects and that code reuse is safe, without even thinking about the possible problems. Right. I think it is a problem that there are assumptions about signature, behavior, specification (pre/post condition), and protocols that have to be dealt with that are now mostly dealt with by comments. It would be great if something better than systematic commenting was available but I am not sure if it belongs in the core language, which is already a bit large. One of the features I'm really missing in Ada is a syntax to specify assertions, pre- and post-conditions and invariants for code and interfaces. Compilers wouldn't have to check these conditions, except some simple cases like static expressions, but they (or external programs) *could* check them and moreover compilers could use them for optimizations. Do you think that this needs to be part of the language proper, or would add-on tools suffice? Wasn't Anna supposed to do fill this goal? Larch? Standardizing an existing tool might be a reasonable interim solution. Any new revision of Ada should address this issue, since it is so closely connected to the design goals of Ada. Indeed. -- Brian