程序设计语言概念(Concepts-of-Programming-Languages)-英文-第10版-第2章

Chapter2EvolutionoftheMajorProgrammingLanguagesCopyright©2012Addison-Wesley.Allrightsreserved.1-2Chapter2TopicsZuse’sPlankalkülMinimalHardwareProgramming:PseudocodesTheIBM704andFortranFunctionalProgramming:LISPTheFirstStepTowardSophistication:ALGOL60ComputerizingBusinessRecords:COBOLTheBeginningsofTimesharing:BASICCopyright©2012Addison-Wesley.Allrightsreserved.1-3Chapter2Topics(continued)EverythingforEverybody:PL/ITwoEarlyDynamicLanguages:APLandSNOBOLTheBeginningsofDataAbstraction:SIMULA67OrthogonalDesign:ALGOL68SomeEarlyDescendantsoftheALGOLsProgrammingBasedonLogic:PrologHistory'sLargestDesignEffort:AdaCopyright©2012Addison-Wesley.Allrightsreserved.1-4Chapter2Topics(continued)Object-OrientedProgramming:SmalltalkCombiningImperativeadObject-OrientedFeatures:C++AnImperative-BasedObject-OrientedLanguage:JavaScriptingLanguagesTheFlagship.NETLanguage:C#Markup/ProgrammingHybridLanguagesCopyright©2012Addison-Wesley.Allrightsreserved.1-5GenealogyofCommonLanguagesCopyright©2012Addison-Wesley.Allrightsreserved.1-6Zuse’sPlankalkülDesignedin1945,butnotpublisheduntil1972NeverimplementedAdvanceddatastructuresfloatingpoint,arrays,recordsInvariantsCopyright©2012Addison-Wesley.Allrightsreserved.1-7PlankalkülSyntaxAnassignmentstatementtoassigntheexpressionA[4]+1toA[5]

|A+1=>AV|45(subscripts)S|1.n1.n(datatypes)Copyright©2012Addison-Wesley.Allrightsreserved.1-8MinimalHardwareProgramming:PseudocodesWhatwaswrongwithusingmachinecode?PoorreadabilityPoormodifiabilityExpressioncodingwastediousMachinedeficiencies--noindexingorfloatingpointCopyright©2012Addison-Wesley.Allrightsreserved.1-9Pseudocodes:ShortCodeShortCodedevelopedbyMauchlyin1949forBINACcomputersExpressionswerecoded,lefttorightExampleofoperations:

01–06absvalue1n(n+2)ndpower 02)07+2n(n+2)ndroot 03=08pause4nif<=n 04/09(58printandtabCopyright©2012Addison-Wesley.Allrightsreserved.1-10Pseudocodes:SpeedcodingSpeedcodingdevelopedbyBackusin1954forIBM701PseudoopsforarithmeticandmathfunctionsConditionalandunconditionalbranchingAuto-incrementregistersforarrayaccessSlow!Only700wordsleftforuserprogramCopyright©2012Addison-Wesley.Allrightsreserved.1-11Pseudocodes:RelatedSystemsTheUNIVACCompilingSystemDevelopedbyateamledbyGraceHopperPseudocodeexpandedintomachinecodeDavidJ.Wheeler(CambridgeUniversity)developedamethodofusingblocksofre-locatableaddressestosolvetheproblemofabsoluteaddressingCopyright©2012Addison-Wesley.Allrightsreserved.1-12IBM704andFortranFortran0:1954-notimplementedFortranI:1957DesignedforthenewIBM704,whichhadindexregistersandfloatingpointhardware-Thisledtotheideaofcompiledprogramminglanguages,becausetherewasnoplacetohidethecostofinterpretation(nofloating-pointsoftware)EnvironmentofdevelopmentComputersweresmallandunreliableApplicationswerescientificNoprogrammingmethodologyortoolsMachineefficiencywasthemostimportantconcernCopyright©2012Addison-Wesley.Allrightsreserved.1-13DesignProcessofFortranImpactofenvironmentondesignofFortranINoneedfordynamicstorageNeedgoodarrayhandlingandcountingloopsNostringhandling,decimalarithmetic,orpowerfulinput/output(forbusinesssoftware)Copyright©2012Addison-Wesley.Allrightsreserved.1-14FortranIOverviewFirstimplementedversionofFortranNamescouldhaveuptosixcharactersPost-testcountingloop(DO)FormattedI/OUser-definedsubprogramsThree-wayselectionstatement(arithmeticIF)NodatatypingstatementsCopyright©2012Addison-Wesley.Allrightsreserved.1-15FortranIOverview(continued)FirstimplementedversionofFORTRANNoseparatecompilationCompilerreleasedinApril1957,after18worker-yearsofeffortProgramslargerthan400linesrarelycompiledcorrectly,mainlyduetopoorreliabilityof704CodewasveryfastQuicklybecamewidelyusedCopyright©2012Addison-Wesley.Allrightsreserved.1-16FortranIIDistributedin1958IndependentcompilationFixedthebugsCopyright©2012Addison-Wesley.Allrightsreserved.1-17FortranIVEvolvedduring1960-62ExplicittypedeclarationsLogicalselectionstatementSubprogramnamescouldbeparametersANSIstandardin1966Copyright©2012Addison-Wesley.Allrightsreserved.1-18Fortran77Becamethenewstandardin1978CharacterstringhandlingLogicalloopcontrolstatementIF-THEN-ELSEstatementCopyright©2012Addison-Wesley.Allrightsreserved.1-19Fortran90MostsignificantchangesfromFortran77ModulesDynamicarraysPointersRecursionCASEstatementParametertypecheckingCopyright©2012Addison-Wesley.Allrightsreserved.1-20LatestversionsofFortranFortran95–relativelyminoradditions,plussomedeletionsFortran2003–supportforOOP,procedurepointers,interoperabilitywithCFortran2008–blocksforlocalscopes,co-arrays,DoConcurrentCopyright©2012Addison-Wesley.Allrightsreserved.1-21FortranEvaluationHighlyoptimizingcompilers(allversionsbefore90)TypesandstorageofallvariablesarefixedbeforeruntimeDramaticallychangedforeverthewaycomputersareusedCopyright©2012Addison-Wesley.Allrightsreserved.1-22FunctionalProgramming:LISPLIStProcessinglanguageDesignedatMITbyMcCarthyAIresearchneededalanguagetoProcessdatainlists(ratherthanarrays)Symboliccomputation(ratherthannumeric)Onlytwodatatypes:atomsandlistsSyntaxisbasedonlambdacalculusCopyright©2012Addison-Wesley.Allrightsreserved.1-23RepresentationofTwoLISPListsRepresentingthelists(ABCD)and(A(BC)D(E(FG)))Copyright©2012Addison-Wesley.Allrightsreserved.1-24LISPEvaluationPioneeredfunctionalprogrammingNoneedforvariablesorassignmentControlviarecursionandconditionalexpressionsStillthedominantlanguageforAICOMMONLISPandSchemearecontemporarydialectsofLISPML,Haskell,andF#arealsofunctionalprogramminglanguages,butuseverydifferentsyntaxCopyright©2012Addison-Wesley.Allrightsreserved.1-25Scheme

DevelopedatMITinmid1970sSmallExtensiveuseofstaticscopingFunctionsasfirst-classentitiesSimplesyntax(andsmallsize)makeitidealforeducationalapplicationsCopyright©2012Addison-Wesley.Allrightsreserved.1-26COMMONLISPAnefforttocombinefeaturesofseveraldialectsofLISPintoasinglelanguageLarge,complex,usedinindustryforsomelargeapplicationsCopyright©2012Addison-Wesley.Allrightsreserved.1-27TheFirstStepTowardSophistication:ALGOL60EnvironmentofdevelopmentFORTRANhad(barely)arrivedforIBM70xManyotherlanguageswerebeingdeveloped,allforspecificmachinesNoportablelanguage;allweremachine-dependentNouniversallanguageforcommunicatingalgorithmsALGOL60wastheresultofeffortstodesignauniversallanguageCopyright©2012Addison-Wesley.Allrightsreserved.1-28EarlyDesignProcessACMandGAMMmetforfourdaysfordesign(May27toJune1,1958)GoalsofthelanguageClosetomathematicalnotationGoodfordescribingalgorithmsMustbetranslatabletomachinecodeCopyright©2012Addison-Wesley.Allrightsreserved.1-29ALGOL58ConceptoftypewasformalizedNamescouldbeanylengthArrayscouldhaveanynumberofsubscriptsParameterswereseparatedbymode(in&out)SubscriptswereplacedinbracketsCompoundstatements(begin...end)SemicolonasastatementseparatorAssignmentoperatorwas:=ifhadanelse-ifclauseNoI/O-“wouldmakeitmachinedependent”Copyright©2012Addison-Wesley.Allrightsreserved.1-30ALGOL58ImplementationNotmeanttobeimplemented,butvariationsofitwere(MAD,JOVIAL)AlthoughIBMwasinitiallyenthusiastic,allsupportwasdroppedbymid1959Copyright©2012Addison-Wesley.Allrightsreserved.1-31ALGOL60OverviewModifiedALGOL58at6-daymeetinginParisNewfeaturesBlockstructure(localscope)TwoparameterpassingmethodsSubprogramrecursionStack-dynamicarraysStillnoI/OandnostringhandlingCopyright©2012Addison-Wesley.Allrightsreserved.1-32ALGOL60EvaluationSuccessesItwasthestandardwaytopublishalgorithmsforover20yearsAllsubsequentimperativelanguagesarebasedonitFirstmachine-independentlanguageFirstlanguagewhosesyntaxwasformallydefined(BNF)Copyright©2012Addison-Wesley.Allrightsreserved.1-33ALGOL60Evaluation(continued)FailureNeverwidelyused,especiallyinU.S.ReasonsLackofI/Oandthecharactersetmadeprogramsnon-portableTooflexible--hardtoimplementEntrenchmentofFortranFormalsyntaxdescriptionLackofsupportfromIBMCopyright©2012Addison-Wesley.Allrightsreserved.1-34ComputerizingBusinessRecords:COBOLEnvironmentofdevelopmentUNIVACwasbeginningtouseFLOW-MATICUSAFwasbeginningtouseAIMACOIBMwasdevelopingCOMTRANCopyright©2012Addison-Wesley.Allrightsreserved.1-35COBOLHistoricalBackgroundBasedonFLOW-MATICFLOW-MATICfeaturesNamesupto12characters,withembeddedhyphensEnglishnamesforarithmeticoperators(noarithmeticexpressions)DataandcodewerecompletelyseparateThefirstwordineverystatementwasaverbCopyright©2012Addison-Wesley.Allrightsreserved.1-36COBOLDesignProcessFirstDesignMeeting(Pentagon)-May1959DesigngoalsMustlooklikesimpleEnglishMustbeeasytouse,evenifthatmeansitwillbelesspowerfulMustbroadenthebaseofcomputerusersMustnotbebiasedbycurrentcompilerproblemsDesigncommitteememberswereallfromcomputermanufacturersandDoDbranchesDesignProblems:arithmeticexpressions?subscripts?FightsamongmanufacturersCopyright©2012Addison-Wesley.Allrightsreserved.1-37COBOLEvaluationContributionsFirstmacrofacilityinahigh-levellanguageHierarchicaldatastructures(records)NestedselectionstatementsLongnames(upto30characters),withhyphensSeparatedatadivisionCopyright©2012Addison-Wesley.Allrightsreserved.1-38COBOL:DoDInfluenceFirstlanguagerequiredbyDoDwouldhavefailedwithoutDoDStillthemostwidelyusedbusinessapplicationslanguageCopyright©2012Addison-Wesley.Allrightsreserved.1-39TheBeginningofTimesharing:BASICDesignedbyKemeny&KurtzatDartmouthDesignGoals:Easytolearnandusefornon-sciencestudentsMustbe“pleasantandfriendly”FastturnaroundforhomeworkFreeandprivateaccessUsertimeismoreimportantthancomputertimeCurrentpopulardialect:VisualBASICFirstwidelyusedlanguagewithtimesharingCopyright©2012Addison-Wesley.Allrightsreserved.1-402.8EverythingforEverybody:PL/IDesignedbyIBMandSHAREComputingsituationin1964(IBM'spointofview)ScientificcomputingIBM1620and7090computersFORTRANSHAREusergroupBusinesscomputingIBM1401,7080computersCOBOLGUIDEusergroupCopyright©2012Addison-Wesley.Allrightsreserved.1-41PL/I:BackgroundBy1963ScientificusersbegantoneedmoreelaborateI/O,likeCOBOLhad;businessusersbegantoneedfloatingpointandarraysforMISItlookedlikemanyshopswouldbegintoneedtwokindsofcomputers,languages,andsupportstaff--toocostlyTheobvioussolutionBuildanewcomputertodobothkindsofapplicationsDesignanewlanguagetodobothkindsofapplicationsCopyright©2012Addison-Wesley.Allrightsreserved.1-42PL/I:DesignProcessDesignedinfivemonthsbythe3X3CommitteeThreemembersfromIBM,threemembersfromSHAREInitialconceptAnextensionofFortranIVInitiallycalledNPL(NewProgrammingLanguage)NamechangedtoPL/Iin1965Copyright©2012Addison-Wesley.Allrightsreserved.1-43PL/I:EvaluationPL/IcontributionsFirstunit-levelconcurrencyFirstexceptionhandlingSwitch-selectablerecursionFirstpointerdatatypeFirstarraycrosssectionsConcernsManynewfeatureswerepoorlydesignedToolargeandtoocomplexCopyright©2012Addison-Wesley.Allrightsreserved.1-44TwoEarlyDynamicLanguages:APLandSNOBOLCharacterizedbydynamictypinganddynamicstorageallocationVariablesareuntypedAvariableacquiresatypewhenitisassignedavalueStorageisallocatedtoavariablewhenitisassignedavalueCopyright©2012Addison-Wesley.Allrightsreserved.1-45APL:AProgrammingLanguageDesignedasahardwaredescriptionlanguageatIBMbyKenIversonaround1960Highlyexpressive(manyoperators,forbothscalarsandarraysofvariousdimensions)ProgramsareverydifficulttoreadStillinuse;minimalchangesCopyright©2012Addison-Wesley.Allrightsreserved.1-46SNOBOLDesignedasastringmanipulationlanguageatBellLabsbyFarber,Griswold,andPolenskyin1964PowerfuloperatorsforstringpatternmatchingSlowerthanalternativelanguages(andthusnolongerusedforwritingeditors)StillusedforcertaintextprocessingtasksCopyright©2012Addison-Wesley.Allrightsreserved.1-47TheBeginningofDataAbstraction:SIMULA67DesignedprimarilyforsystemsimulationinNorwaybyNygaardandDahlBasedonALGOL60andSIMULAIPrimaryContributionsCoroutines-akindofsubprogramClasses,objects,andinheritanceCopyright©2012Addison-Wesley.Allrightsreserved.1-48OrthogonalDesign:ALGOL68FromthecontinueddevelopmentofALGOL60butnotasupersetofthatlanguageSourceofseveralnewideas(eventhoughthelanguageitselfneverachievedwidespreaduse)DesignisbasedontheconceptoforthogonalityAfewbasicconcepts,plusafewcombiningmechanismsCopyright©2012Addison-Wesley.Allrightsreserved.1-49ALGOL68EvaluationContributionsUser-defineddatastructuresReferencetypesDynamicarrays(calledflexarrays)CommentsLessusagethanALGOL60Hadstronginfluenceonsubsequentlanguages,especiallyPascal,C,andAdaCopyright©2012Addison-Wesley.Allrightsreserved.1-50Pascal-1971DevelopedbyWirth(aformermemberoftheALGOL68committee)DesignedforteachingstructuredprogrammingSmall,simple,nothingreallynewLargestimpactwasonteachingprogrammingFrommid-1970suntilthelate1990s,itwasthemostwidelyusedlanguageforteachingprogrammingCopyright©2012Addison-Wesley.Allrightsreserved.1-51C-1972Designedforsystemsprogramming(atBellLabsbyDennisRichie)EvolvedprimarilyfromBCLPandB,butalsoALGOL68Powerfulsetofoperators,butpoortypecheckingInitiallyspreadthroughUNIXThoughdesignedasasystemslanguage,ithasbeenusedinmanyapplicationareasCopyright©2012Addison-Wesley.Allrightsreserved.1-52ProgrammingBasedonLogic:PrologDeveloped,byComerauerandRoussel(UniversityofAix-Marseille),withhelpfromKowalski(UniversityofEdinburgh)BasedonformallogicNon-proceduralCanbesummarizedasbeinganintelligentdatabasesystemthatusesaninferencingprocesstoinferthetruthofgivenqueriesComparativelyinefficientFewapplicationareasCopyright©2012Addison-Wesley.Allrightsreserved.1-53History’sLargestDesignEffort:AdaHugedesigneffort,involvinghundredsofpeople,muchmoney,andabouteightyearsSequenceofrequirements(1975-1978)(Strawman,Woodman,Tinman,Ironman,Steelman)NamedAdaafterAugustaAdaByron,thefirstprogrammerCopyright©2012Addison-Wesley.Allrightsreserved.1-54AdaEvaluationContributionsPackages-supportfordataabstractionExceptionhandling-elaborateGenericprogramunitsConcurrency-throughthetaskingmodelCommentsCompetitivedesignIncludedallthatwasthenknownaboutsoftwareengineeringandlanguagedesignFirstcompilerswereverydifficult;thefirstreallyusablecompilercamenearlyfiveyearsafterthelanguagedesignwascompletedCopyright©2012Addison-Wesley.Allrightsreserved.1-55Ada95Ada95(beganin1988)SupportforOOPthroughtypederivationBettercontrolmechanismsforshareddataNewconcurrencyfeaturesMoreflexiblelibrariesAda2005InterfacesandsynchronizinginterfacesPopularitysufferedbecausetheDoDnolongerrequiresitsusebutalsobecauseofpopularityofC++Copyright©2012Addison-Wesley.Allrightsreserved.1-56Object-OrientedProgramming:SmalltalkDevelopedatXeroxPARC,initiallybyAlanKay,laterbyAdeleGoldbergFirstfullimplementationofanobject-orientedlanguage(dataabstraction,inheritance,anddynamicbinding)PioneeredthegraphicaluserinterfacedesignPromotedOOPCopyright©2012Addison-Wesley.Allrightsreserved.1-57CombiningImperativeandObject-OrientedProgramming:C++DevelopedatBellLabsbyStroustrupin1980EvolvedfromCandSIMULA67Facilitiesforobject-orientedprogramming,takenpartiallyfromSIMULA67Alargeandcomplexlanguage,inpartbecauseitsupportsbothproceduralandOOprogrammingRapidlygrewinpopularity,alongwithOOPANSIstandardapprovedinNovember1997Microsoft’sversion:MC++Properties,delegates,interfaces,nomultipleinheritanceCopyright©2012Addison-Wesley.Allrightsreserved.1-58RelatedOOPLanguagesObjective-C(designedbyBradCox–early1980s)CplussupportforOOPbasedonSmalltalkUsesSmalltalk’smethodcallingsyntaxUsedbyAppleforsystemsprogramsDelphi(Borland)PascalplusfeaturestosupportOOPMoreelegantandsaferthanC++Go(designedatGoogle-2009)LooselybasedonC,butalsoquitedifferentDoesnotsupporttraditionalOOPCopyright©2012Addison-Wesley.Allrightsreserved.1-59AnImperative-BasedObject-OrientedLanguage:JavaDevelopedatSunintheearly1990sCandC++werenotsatisfactoryforembeddedelectronicdevicesBasedonC++Significantlysimplified(doesnotincludestruct,union,enum,pointerarithmetic,andhalfoftheassignmentcoercionsofC++)SupportsonlyOOPHasreferences,butnotpointersIncludessupportforappletsandaformofconcurrencyCopyright©2012Addison-Wesley.Allrightsreserved.1-60JavaEvaluationEliminatedmanyunsafefeaturesofC++SupportsconcurrencyLibrariesforapplets,GUIs,databaseaccessPortable:JavaVirtualMachineconcept,JITcompilersWidelyusedforWebprogrammingUseincreasedfasterthananypreviouslanguageMostrecentversion,7,releasedin2011Copyright©2012Addison-Wesley.Allrightsreserved.1-61ScriptingLanguagesfortheWebPerlDesignedbyLarryWall—firstreleasedin1987VariablesarestaticallytypedbutimplicitlydeclaredThreedistinctivenamespaces,denotedbythefirstcharacterofavariable’snamePowerful,butsomewhatdangerousGainedwidespreaduseforCGIprogrammingontheWebAlsousedforareplacementforUNIXsystemadministrationlanguageJavaScriptBeganatNetscape,butlaterbecameajointventureofNetscapeandSunMicrosystemsAclient-sideHTML-embeddedscriptinglanguage,oftenusedtocreatedynamic