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: fac41,2c6139ce13be9980 X-Google-Attributes: gidfac41,public X-Google-Thread: f43e6,2c6139ce13be9980 X-Google-Attributes: gidf43e6,public X-Google-Thread: 103376,3d3f20d31be1c33a X-Google-Attributes: gid103376,public X-Google-Thread: 1108a1,2c6139ce13be9980 X-Google-Attributes: gid1108a1,public From: Nick Leaton Subject: Re: Safety-critical development in Ada and Eiffel Date: 1997/08/22 Message-ID: <33FD5224.442A614C@calfp.co.uk>#1/1 X-Deja-AN: 267858431 References: <5siqrr$3of@jupiter.milkyway.org> <5smgts$p68$1@miranda.gmrc.gecm.com> <33EFCCE4.4CE0@flash.net> <5sq3fh$frg@wdl1.wdl.lmco.com> <33F9C7BD.794BDF32@eiffel.com> <33FAB260.7E0CD1D1@calfp.co.uk> Reply-To: nickle@pauillac X-NNTP-Posting-Host: calfp.demon.co.uk [158.152.70.168] Newsgroups: comp.object,comp.software-eng,comp.lang.ada,comp.lang.eiffel Date: 1997-08-22T00:00:00+00:00 List-Id: Jon S Anthony wrote: > > Robert Dewar wrote: > > > [...some BM stuff...] > > > you mean by "know better". If you mean do I know perfectly well that > > > postconditions cannot capture this kind of specification, yes, I know > > > that perfectly well -- many specifications and requirements cannot be > > > formalized in any useful manner. > > What's really odd here is that BM does not give the impression that he > understands this point. Go figure. I think he does. I read a least one message in the last two days by BM where he makes this point. Reiterating a point I have made else where. In what cases does DBC detract from a solution? > > But who should be resposible for the error message? You have a choice > > between client of print and print itself. > > Hint: it is not the dichotomy as you suggest. OK, If I don't have a print system where I can have resposibility as a client I have a problem. I must have DBC. Now if you are saying that I some cases I don't want to bother, which isn't an unreasonable in the case of print, I agree. In this case a default handler makes sense, but this is just being nice. You must be able to take the DBC route with the client accepting responsibility. > > The answer must be the client, because as the client, I may want to > > handle errors in different ways. Pop up a window, or print to a console > > window as two reasonable examples. > > That's not the point. The point is, what is expressed via the > _mechanisms_ you suggest. This latter depends largely on the context > of who/what is using the system (client and print together). -- Nick