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,df854b5838c3e14 X-Google-Attributes: gid103376,public From: jsa@organon.com (Jon S Anthony) Subject: Re: C/C++ knocks the .... Date: 1996/02/19 Message-ID: #1/1 X-Deja-AN: 140154350 sender: news@organon.com (news) references: <4g2r2r$ded@stc06.ctd.ornl.gov> organization: Organon Motives, Inc. newsgroups: comp.lang.ada Date: 1996-02-19T00:00:00+00:00 List-Id: In article stt@henning.camb.inmet.com (Tucker Taft) writes: > Matt Kennel (kennel@msr.epm.ornl.gov) wrote: > : ... > : As for Ada, I'm not yet fully convinced abou the package vs > : type thing. C++ might be ugly because you can have all sorts of > : elements outside classes, but in Eiffel you cannot. > > : Eiffel intentionally makes the unit of namespace and of type > : the same. > > : The question is, do the benefits of having them completely separate > : make up for the extra work and complexity of having to double the > : number of 'mental units' in most idiomatic programs. (and without > : MI you have to go a bit further) > > : Yes, Ada has them on orthogonal axes. Eiffel only has "one axis" > : but it may empirically be along the major princpal component with > : only a small deviation in other directions. > > On the other hand, various Eiffel implementations have felt the > need to add yet another language on top for doing "configuration" > of large systems (I think it is called "GRACE"?). This seems > to indicate that programmers have a need to deal with larger groupings > than that represented by a single class. Although one could conceivably > just create larger and larger classes, at some point the model of a "type" > breaks down, whereas the notion of a package scales nicely to the > notion of a subsystem, as in Ada 95. You are thinking of "Lace" (Language for Assembling Classes in Eiffel). It is not part of the Eiffel language, but is a suggested component of any Eiffel environment. See ETL by Meyer. My own belief on this issue is that the approach adopted by STT in Ada95 is _by far_ the better of the two. In fact, I would now consider it one of the primary advantages of Ada over things like Eiffel, Sather, SmallTalk, (and C++, though it has many other serious problems). Coupled with the notion of an extensible heirarchical library, it is definitely one of the very best type/component structuring constructs available in any current programming language. /Jon -- Jon Anthony Organon Motives, Inc. 1 Williston Road, Suite 4 Belmont, MA 02178 617.484.3383 jsa@organon.com