OnFormalismInSpecifications - On Formalism in...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: On Formalism in Specifications- BertrandMeyer, University of California, SantaBarbara A critiqueofa natural-language specification, pecificationisthesoftwarelife- followedbypresentationofamathematical Scycle phaseconcernedwithprecise alternative,demonstrates definition ofthetaskstobeperformed theweaknessof bythe system.Althoughsoftwareen- naturallanguage gineering textbooks emphasize its ne- A .-> *s4C. naturallanguage cessity,thespecificationphaseisoften andthe strength overlooked in practice. Or, more pre- offormalism cisely,itis confused witheitherthe in requirements precedingphase,definitionofsystem specifications. objectives, or thefollowingphase,de- sign.Inthefirstcase, consideredhere in particular, a natural-language re- quirementsdocument isdeemed suf- ficienttoproceedtosystemdesign- withoutfurther specificationactivity. This articleemphasizes the draw- backsofsuchan informalapproach and shows theusefulness of formal specifications. To avoid possiblemis- understanding, however, let'sclarify onepointattheoutset:We innoway advocate formal specifications as a replacementfornatural-language re- quirements; rather, we viewthemasa complement to natural-language de- scriptionsand,aswillbeillustratedby an example, asanaidin improving the qualityofnatural-languagespecifica- tions. Readers already convinced of the benefitsofformalspecificationsmight findinthisarticle some useful argu- ments to reinforce their viewpoint. Readersnot sharingthisviewwill, we hope, find some interesting ideasto ponder. Theseven sins ofthe specifier The study of requirements docu-- = ° cS('1W- ments,astheyareroutinelyproduced in industry,yieldsrecurringpatterns of 0740-7459/85/0001/0006$01.00- 1985 IEEE 6 IEEESOFTWARE deficiencies.Table Ilistssevenclasses ofdeficienciesthatwe havefoundto be both common and particularly damaging to the qualityof require- ments. The classificationis interestingfor tworeasons. First,byshowingthepit- fallsof natural-languagerequirements documents,it gives some weighttothe thesis that formal specificationsare needed as an intermediate step be- tween requirementsand design.Sec- ond, since natural-language require- ments are necessary whether or not oneacceptsthethesisthattheyshould becomplementedwithformal specifi- cations,itprovideswritersofsuchre- quirements with a checklistofcom- mon mistakes.Writersofmost kinds ofsoftwaredocumentation(userman- uals, programminglanguagemanuals, etc.)shouldfindthislistuseful;we'll demonstrateitsusethroughanexam- plethatexhibitsallthedefectsexcept thelastone. Arequirementsdocument The reader isinvited tostudy, in lightofthepreviouslist,someofthe sof,ware documentation availableto him.We coulddothesamehereand discuss actual requirements docu- ments,takenfromindustrialsoftware projects,aswedidinapreviousver- sionofthisarticle. Butsuchadiscus- sionisnot entirelysatisfactory; the readermayfeelthattheexamplescho- senarenotrepresentative.Also,one sometimeshearstheremarkthatnoth- ingisinherentlywrong withnatural- languagespecifications.Allonehastolanguagespecifications....
View Full Document

This note was uploaded on 01/09/2012 for the course EMP EMP5117 taught by Professor Bohehm during the Fall '11 term at University of Ottawa.

Page1 / 21

OnFormalismInSpecifications - On Formalism in...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online