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: fac41,9a0ff0bffdf63657 X-Google-Attributes: gidfac41,public X-Google-Thread: 1108a1,9a0ff0bffdf63657 X-Google-Attributes: gid1108a1,public X-Google-Thread: f43e6,9a0ff0bffdf63657 X-Google-Attributes: gidf43e6,public X-Google-Thread: 103376,4b06f8f15f01a568 X-Google-Attributes: gid103376,public From: doylep@ecf.toronto.edu (Patrick Doyle) Subject: Re: Module size (was Re: Software landmines) Date: 1998/09/06 Message-ID: #1/1 X-Deja-AN: 388333210 X-Nntp-Posting-Host: spark23.ecf Sender: news@ecf.toronto.edu (News Administrator) References: <6snlos$bh6$1@hirame.wwa.com> <35F0BC05.61919244@s054.aone.net.au> <6srhl8$spv$1@hirame.wwa.com> <35F1B435.403AE1AC@s054.aone.net.au> Organization: University of Toronto, Engineering Computing Facility Newsgroups: comp.lang.eiffel,comp.object,comp.software-eng,comp.lang.ada Date: 1998-09-06T00:00:00+00:00 List-Id: In article <35F1B435.403AE1AC@s054.aone.net.au>, Loryn Jenkins wrote: >> class Shape >> { >> public: >> virtual void Draw() = 0; // Draw shape on screen. >> } >> >> class Pump >> { >> public: >> virtual void Draw() = 0; // draw water from the pump. >> }; >> >> Here are two classes that appear to have the same interface. > > >But they don't have the same interface. It is just that your formalism >doesn't have the power to describe the semantics. Were this written in >Eiffel, you would find the postconditions and invariant, and possibly >the preconditions, would differ. > >Thus the interfaces are quite different. And yet, if these two classes were both inherited into a third class, would these two features no be merged into one? It seems that, at some level, even Eiffel regards these two interface points as being equivalent. -PD -- -- Patrick Doyle doylep@ecf.toronto.edu