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: f43e6,9a0ff0bffdf63657 X-Google-Attributes: gidf43e6,public X-Google-Thread: 1108a1,9a0ff0bffdf63657 X-Google-Attributes: gid1108a1,public X-Google-Thread: 103376,4b06f8f15f01a568 X-Google-Attributes: gid103376,public From: dewarr@my-dejanews.com Subject: Re: Software landmines (loops) Date: 1998/09/01 Message-ID: <6sfmi5$41e$1@nnrp1.dejanews.com>#1/1 X-Deja-AN: 386659480 References: <902934874.2099.0.nnrp-10.c246a717@news.demon.co.uk> <6r1glm$bvh$1@nnrp1.dejanews.com> <6r9f8h$jtm$1@nnrp1.dejanews.com> <6renh8$ga7$1@nnrp1.dejanews.com> <6rf59b$2ud$1@nnrp1.dejanews.com> <6rfra4$rul$1@nnrp1.dejanews.com> <35DBDD24.D003404D@calfp.co.uk> <6sbuod$fra$1@hirame.wwa.com> <35f51e53.48044143@ <904556531.666222@miso.it.uq.edu.au> X-Http-Proxy: 1.0 x11.dejanews.com:80 (Squid/1.1.22) for client 205.232.38.14 Organization: Deja News - The Leader in Internet Discussion X-Article-Creation-Date: Tue Sep 01 02:35:49 1998 GMT Newsgroups: comp.lang.eiffel,comp.object,comp.software-eng,comp.lang.ada X-Http-User-Agent: Mozilla/2.02 (OS/2; I) Date: 1998-09-01T00:00:00+00:00 List-Id: In article <904556531.666222@miso.it.uq.edu.au>, ahussey@it.uq.edu.au (Andrew Hussey) wrote: > In Matthew Heaney writes: > > >I can almost live that. The real problem, however, is that using an > >extra flag to terminate VASTLY complicates the predicate. In fact, the > >flag doubles the number of states I have to think about when mentally > >evaluating the predicate! That's the real source of the loop > >termination errors. > > >(I shouldn't have to remind anyone, but just in case: George Miller did > >a famous study about human cognitive limits, and found that people can > >remember about 7 things, plus or minus 2. That's why complex predicates > >make a programmer's head spin, and why he often gets loop termination > >wrong.) > > >Using an exit from the middle avoids the headaches (literally) > >engendered by using an extra flag in the predicate. When you want to > >exit, you just say that you want to exit, directly. No mental > >gymnastics are required in order to determine whether you'll "really" > >exit, as would be the case using the flag approach. > > That's brilliant, now your code is much easier to write! > Now let's see who has an easier time *testing* their code. > I think you'll find the control-flow errors you introduce > in the spaghetti you produce will more than make up for > any gain you have from rapid coding. > > A. > > If you think that the use of a goto necessarily results in "spaghetti code", then you simply don't understand the (useful) concept of spaghetti code. I often see this, people don't really understand the issues at all, but want to reduce their lack of understanding to a simple rule ("never use a goto"). I guess that if you don't have any understanding of the issues, this is not a terrible rule, but it will result in less clear code in some cases. -----== Posted via Deja News, The Leader in Internet Discussion ==----- http://www.dejanews.com/rg_mkgrp.xp Create Your Own Free Member Forum