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: f43e6,2c6139ce13be9980 X-Google-Attributes: gidf43e6,public X-Google-Thread: 103376,3d3f20d31be1c33a X-Google-Attributes: gid103376,public X-Google-Thread: fac41,2c6139ce13be9980 X-Google-Attributes: gidfac41,public X-Google-Thread: 1108a1,2c6139ce13be9980 X-Google-Attributes: gid1108a1,public From: jsa@alexandria.organon.com (Jon S Anthony) Subject: Re: Interface/Implementation (was Re: Design by Contract) Date: 1997/09/06 Message-ID: #1/1 X-Deja-AN: 270333337 References: <340F20A0.49B5@ac3i.dseg.ti.com> <340F39E3.4B71@pseserv3.fw.hac.com> Distribution: world Organization: PSINet Newsgroups: comp.object,comp.software-eng,comp.lang.ada,comp.lang.eiffel Date: 1997-09-06T00:00:00+00:00 List-Id: In article doylep@ecf.toronto.edu (Patrick Doyle) writes: > My point is that deferred classes *are* interfaces, so if you > want to freeze an interface, freeze a deferred class. And? I'm not sure what you are fishing for - an Ada spec. is simply a different kind of thing. It _provides_ a "bundled" (aka packaged) interface or several interfaces depending on what is packaged up in it. > See--it has little to do with Ada. I'm simply referring to Ada > because it has a built-in facility for creating interfaces for > every class, and so the Ada people have a great deal of experience > with this methodology; so I was asking them about using deferred > classes because presumably they'd be the best ones to find the > flaws in the deferred class methodology. Maybe that's the problem. Why should there be a "flaw"? It's just a different thing. Package specs provide encapsulated interfaces. The package specs. themselves can't be derived and can't be inherited. They have nothing corresponding to them at runtime (whereas a deferred or abstract class should have a jump table. Well, probably...) /Jon -- Jon Anthony OMI, Belmont, MA 02178, 617.484.3383 "Nightmares - Ha! The way my life's been going lately, Who'd notice?" -- Londo Mollari