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 X-Google-Thread: 103376,6960ceaa57428e2f X-Google-Attributes: gid103376,public From: Karel Thoenissen Subject: Re: Another important feature of Ada Date: 2000/11/18 Message-ID: <3A16C0E8.91A39DA7@hello.nl>#1/1 X-Deja-AN: 695148924 Content-Transfer-Encoding: 8bit References: <3A12041B.BCFD8CA0@worldnet.att.net> <8uu6tf$63d$1@nnrp1.deja.com> <3A12BBC6.E3FDAB0F@averstar.com> <8v5dkm$ftt$1@wanadoo.fr> X-Accept-Language: nl,de,en Content-Type: text/plain; charset=iso-8859-1 X-Complaints-To: abuse@nl.uu.net X-Trace: porthos.nl.uu.net 974569612 27816 213.116.96.147 (18 Nov 2000 17:46:52 GMT) Organization: UUNET-NL (http://www.nl.uu.net) Mime-Version: 1.0 NNTP-Posting-Date: 18 Nov 2000 17:46:52 GMT Newsgroups: comp.lang.ada Date: 2000-11-18T17:46:52+00:00 List-Id: Ed Falis schreef: > Jean-Pierre Rosen wrote: > > > The importance of separating specs from bodies is *not* the ability to > > view them separatly, which can be accomplished with a tool as > > you note. It is the ability to compile the spec, and compile users of > > the spec before even thinking about the implementation. > > Therefore you can check the spec, and check that the spec matches the > > needs without being influenced by implementation constraints > > (which often leads to over-specification). > > Yes, I should have mentioned that this is easily (and often) done in > Eiffel using completely deferred classes with assertions. A deferred > class is similar to an abstract tagged type in a package. > > I agree with your point about the value of being able to compile against > unimplemented specs - it's always been one of my favorite aspects of > Ada. But the same effect can be achieved otherwise. > > - Ed True, but at the cost of doubling the number of classes in the hierarchy and spilling the name space. -- Groeten, Karel Th�nissen