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: 1108a1,9a0ff0bffdf63657 X-Google-Attributes: gid1108a1,public X-Google-Thread: 103376,4b06f8f15f01a568 X-Google-Attributes: gid103376,public X-Google-Thread: f43e6,9a0ff0bffdf63657 X-Google-Attributes: gidf43e6,public X-Google-Thread: fac41,9a0ff0bffdf63657 X-Google-Attributes: gidfac41,public From: "Robert Martin" Subject: Re: Software landmines (loops) Date: 1998/09/01 Message-ID: <6shunm$47g$1@hirame.wwa.com>#1/1 X-Deja-AN: 386958010 References: <902934874.2099.0.nnrp-10.c246a717@news.demon.co.uk> <6r1glm$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$1@hirame.wwa.com><35f51e53.48044143@ <904556531.666222@miso.it.uq.edu.au> <35EAB5B1.1DA1986B@ehpt.com><6sf1dn$n52$1@hirame.wwa.com> <35EB9B91.3FF8583@ehpt.com><6sh2rp$8v3$1@hirame.wwa.com> X-MimeOLE: Produced By Microsoft MimeOLE V4.72.2106.4 Organization: WorldWide Access - Midwestern Internet Services - www.wwa.com Newsgroups: comp.lang.eiffel,comp.object,comp.software-eng,comp.lang.ada Date: 1998-09-01T00:00:00+00:00 List-Id: Robert I. Eachus wrote in message ... >In article <6sh2rp$8v3$1@hirame.wwa.com> "Robert Martin" writes: > > > Now certainly it is easier to write the functions with multiple exits. And > > if the functions never change, then you have won; and using a structured > > programming approach would be a net loss. However, functions generally > > don't remain the same. Most of the time they <> (remember Kahn > > talking about how his "pets" enter through your ear and live inside your > > brain? "Later", he said, " as they <>...") Functions that have not > > been built using structured programming can degrade pretty badly when they > > <>. > > Ada programmers are not used to functions growing. An abstraction >is written once, then used forever. If it needs to be extended, you >derive from it (called subtyping or subclassing in other OO languages), >or extend the type locally with locally declared subprograms. >Modifying existing code is a very rare process, and it usually >involves changes, not growth. Package specs often grow during >development, but that is usually due to recognizing the need or >potential need for some additional operation to be exported. This is, in fact, a characteristic of any good OO design that conforms to the Open/Closed principle. New featuers are added by adding new code; not by changing old working code. Nevertheless, functions sometimes do change; and when they do its nice to have the structured so as to facilitate those changes. Robert C. Martin | Design Consulting | Training courses offered: Object Mentor | rmartin@oma.com | Object Oriented Design 14619 N Somerset Cr | Tel: (800) 338-6716 | C++ Green Oaks IL 60048 | Fax: (847) 918-1023 | http://www.oma.com "One of the great commandments of science is: 'Mistrust arguments from authority.'" -- Carl Sagan