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: 103376,4b06f8f15f01a568 X-Google-Attributes: gid103376,public X-Google-Thread: 1108a1,9a0ff0bffdf63657 X-Google-Attributes: gid1108a1,public X-Google-Thread: f43e6,9a0ff0bffdf63657 X-Google-Attributes: gidf43e6,public From: Ell Subject: Re: Software landmines (loops) Date: 1998/09/02 Message-ID: <8SeH1.542$495.132579351@newsreader.digex.net>#1/1 X-Deja-AN: 387183772 References: <6r9f8h$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$1@hirame.wwa.com> <904556531.666222@miso.it.uq.edu.au> <6sgror$je8$3@news.indigo.ie> <6sh3qn$9p2$1@hirame.wwa.com> <35ece7ee.1489912@news.erols.com> <35ED7082.1889@hfl.tc.faa.gov> X-Complaints-To: abuse@digex.net X-Trace: newsreader.digex.net 904755716 205.197.245.192 (Wed, 02 Sep 1998 13:01:56 EDT) Organization: The Universe User-Agent: tin/pre-1.4-980226 (UNIX) (SunOS/4.1.4 (sun4m)) NNTP-Posting-Date: Wed, 02 Sep 1998 13:01:56 EDT Newsgroups: comp.lang.eiffel,comp.object,comp.software-eng,comp.lang.ada Date: 1998-09-02T00:00:00+00:00 List-Id: In comp.object Robert Oliver wrote: : Ell wrote: :> The assertion that "single entry, single exit" is a required, or even :> desirable, maxim of structured programming is a myth. :> :> No one (including RCM) can show that this maxim is in fact a coding :> heuristic put forward by any of the founders of the structured :> paradigm. [Check past posts in this thread.] : Edward Yourdan, in his book Techniques of Program Structure and Design : discusses this article: : C. Bohm and G. Jacopini, "Flow Diagrams, Turing Machines, and Languages : with Only two Formation Rules", Communications of the ACM, May 1996, : pages 366-371. : (Is this not *the* foundational article for structured programming?) How can an artile written in '96 be *the* foundational article for the structured programming paradigm which gained currency in the late '70's? : Yourdan says: : "According to Bohm and Jacopini, we need three basic building blocks in : order to construct a program: : 1. A process box. : 2. A generalized loop mechanism. : 3. A binary-decision mechanism. : The process box, shown in Fig. 4.1, may be thought of as a single : computational statement (or machine language instruction) *or as any : other proper conputational sequence with only one entry and one exit* - : such as a subtoutine." Where is the proof that this underlays the structured paradigm and an assertion that something is "proper" doesn't make it so. What structured programming avoided was unstructured flow control. It encouraged the use of procedure/routine calls over 'goto'. Along with entry into a procedure via a call, the use of 'return' is structured flow control; 'return' can only go back to the calling procedure, unlike 'goto' which can branch to a label anywhere. Elliott -- :=***=: Objective * Pre-code Modelling * Holistic :=***=: Hallmarks of the best SW Engineering "The domain object model is the foundation of OOD." Check out SW Modeller vs SW Craftite Central : www.access.digex.net/~ell Copyright 1998 Elliott. exclusive of others' writing. may be copied without permission only in the comp.* usenet and bitnet groups.