SPACE 1

home *** CD-ROM | disk | FTP | other *** search

/ SPACE 1 / SPACE - Library 1 - Volume 1.iso / apps / 150 / sheet.doc < prev next >

Wrap

Text File | 1988-03-13 | 19KB | 379 lines

0660103030566 1Sheet.DocBy Chor-ming Lung16-Feb, 1988 2page # 9[....................................................] êPreface:Ç  Ihaveusedspreadsheetforquiteawhile,andIfeltit isafantastictool.MymostfamiliarspreadsheetisLotus 123(orVIPprofessional).OnethingthatIfeelterribleis itsMACROlanguage.Itisnotasuser-friendlyasits display.IfeelBASICismoresuitablethanMACROfora spreadsheetlanguage.  So,IthinkthatmaybeprofitabletowriteaBASIC interpreterinaspreadsheetenvironment.ThefirstthingI havetodoiscreatingthespreadsheetprogram.  IhadwrittenacalculatorprogramusingPersonal Pascal.Hence,Icanborrowalotoffunctionsfromthat program.AfterIfinishedthebook"ATARISTAPPLICATION PROGRAMMING"byPOLLACKandWEBERfromBANTAM,Ifelt ifIwantedtotakefulluseofGEM,IhavetoswitchtoC language.  Tospeeduptheprocessofwritingthespreadsheet,I wasthinkingtodownloadsomepublicdomainspreadsheet programsandlearnedfromthemfirst.ThefirstoneItried isaMODULA-2programwrittenforBYTEmagazine.Tomy surprise,Icouldnotunderstandthesourcefile.Iknew thereisanotherpublicdomainspreadsheetprogram-- MICROCAL(fromBorlandforTurboPascal).Thisprogramis mucheasiertounderstand.Ilearnedwhatisessentialfor buildingaspreadsheetprogramfromit.  WithMICROCAL,BANTAMbook,andmycalculatorprogram,I thinkIcanmakearobustspreadsheetveryfast.After3and halfmonthsstruggle,Ihaveausablespreadsheetrunning now.  ThespreadsheetisnotdoneyetandtheBASIC interpreterisstillalongwaytogo.Anyway,Ifeelthe spreadsheetisquiteusableeveninitsinfantstage. êDisclaimerÇ:  Ihavemadeeveryefforttoinsuretheaccuracyofthe program.However,thereisnowarrantyeitherexpressor impliedforitsuses. êProgramspecificationÇ:  SHEET(thenameofthisprogram)iswritteninMark WilliamsC.Theaccuracyforrealnumber(double)inMark WilliamsCisupto17digits(Lotus123isupto15digits). Therangeofcalculationis-1E-37to1E+37.Each spreadsheetcontains255by1280cellsandthespreadsheetis implementedbyusingSparseMatrix.(äWhatdoesSparceMatrix mean?Simplyspeaking,theemptycellswillnotoccupyany computermemory.So,youcaninsertsomethingincell "IU1280"withoutrunninginto"NOTENOUGHMEMORY"errorÇ).But therearesomepeculiareffectsthatisduetoSparseMatrix. Iwillrefertothislater.Anyinputtoacellwillbe tokenizedbeforeitisbeinginserted.Currently,onlyone windowcanbeused.Thefutureversionwillsupportupto4 windows. ê RequirementsÇ: *Atari520STor1040STwithdiskdrive(s). *Monochromeorcolormonitor. *BothSHEET.PRGandCALC.RSConthesamedirectory. ê HowtolocateacellÇ:  IassumeyouknowhowtooperatewithGEM.  Tolocateacell, -useverticalandhorizontalsliderbarsto movetothedesireddisplayrange. -putthemouseoverthedesiredcellandpress leftbutton. êCellinputÇ:  TheoperationofcellinputissimilartoLotus123. Anythingyoutypewillbeinsertedintotheeditingbuffer. äSpecialkey:Ç  <Backspace>erasesthelastcharacter. <Return>terminatesinputandthecellcursor remainsonthesamecell. <UParrow>terminatesinputandthecellcursor moves onerowupifpossible. <Downarrow>terminatesinputandthecellcursor movesonerowdownifpossible. <Leftarrow>terminatesinputandthecellcursor movesonecolumnleftifpossible. <Rightarrow>terminatesinputandthecellcursor movesonecolumnrightifpossible. <Shift-arrows>terminatesinputandmovesthecell cursorinthedirectionyouspecifiedby page. äSpecialoperations:Ç <MOUSE>ifthemousecursorisinsidethedisplay rangeandifyoupresstheleftbutton, thecellcoordinatethatthemouseis overwillbeinsertedintotheediting buffer.(Sometimes,GEMdetectsthemouse eventveryfast.Butsometimesitdoes not.So,ifyouseenothingonthe editinglinewhenyoupressthemouse leftbutton,pressitalittlebit longer.Theproblemmaybecausedbytoo manyhide_mouse,show_mousecalls.Ifyou rebootthesystem,itwillalwaysdetect themouseeventveryfast.) <Sliders>Youcanchangethedisplayrangeby movingtheverticalorhorizontalslider bars.Butexcept<Backspace>,anyspecial keywillresumethedisplaybacktothe displayrangebeforeediting. êCelleditingÇ:  Press<F2>andthecurrentcell'scontentwillbe insertedintotheeditingbuffer.êTheeditingsessionmustbe Çêterminatedby<ReturnÇ>. äSpecialkey:Ç <Leftarrow>moveonecharacterleftifpossible <Rightarrow>moveonecharacterrightifpossible <Shift-leftarrow>movetheeditingcursortotheleftmost character <Shift-rightarrow>movetheeditingcursortotherightmost character <Insert>toggletheINSERTmode. <Backspace>Deletethecharacterontheleftsideof editingcursor. <Delete>Deletethecharacterontherightsideof editingcursor. êtypeofinputÇ: (äInputarecase-insensitiveÇ) üFORMULA:ÇInputstringstartswith"+","-",digits,"(" üSTATEMENT:ÇStringstartswith"!" üCOMMAND:ÇStringstartswith"@" üTEXT:ÇStringstartswith"\""orcharacterother thanaboveleadingcharacter. äDifferencesbetweentypes:Ç  Internally,üFORMULAÇwillbeseparatedtoüFORMULAÇor üCONSTANTÇdependingwhethertheformulareferstoother cellsorothervariables(Yes,youcanusevariables. Remember,wewillhaveaBASICinterpreter).Acell containsüCONSTANTÇwillneverberecalculated.Itshould speedupthespreadsheetrecalculationtime. ü STATEMENTÇistokenizedBASICstatements.Youcan havemultiplestatementswith":"asseparator.(äRight now,everyinputSTATEMENTwillbeexecutedbefore insertingintothecurrentcell.Itshouldnotbeso. Therearetworeasonsforthat.First,Iwanttotest eachstatement.Second,IdonothavetheRUNstatement yetÇ.)Currently,therearejustafewstatementsbeing implemented: üSAVEÇ:Thesameaschoosingmenuitem"Save" üLOADÇ:Thesameaschoosingmenuitem"Load" ü=(Assigment)Ç: äcomparethefollowings:Ç +c1=12Itisalogicaloperation.A onemeansTRUEandzeromeans FALSE. !c1=12Itisastatementthatchanges thecontentofcell"C1"toa constantvalue12. üIFÇ:IFäconditionÇTHENästatementsÇ(ELSE ästatements)ÇTheELSEstatementis optional. üDEFINEÇ:Forusewithuserdefinefunctions.(äIn thefuture,alltheuserdefined functionswillbeonafilecall FORMULA.DEF.Youhavetodefineyour functionsbeforecallingSHEET.Ç) äe.g.Ç!definef(x,y)=3*x+4*y Inanycell,type+f(3,4),youwill have25asaresult. üNOTEÇ:-DonotuseüDEFINEÇasCOMMAND. -Inthecellthefunctionf(x,y) beingdefined,youwillsee: DEFINEF(X,Y)=3*PARAM1+4*PARAM2 üYouhavetomanuallychange PARAMxÇwhenyouwanttochange itsdefinitionbyusing<F2>. -Eachfunctioncanhaveatmost 9andatleastoneparameters. -Youhavetodefinethe functionsagaineachtimeyou loadthespreadsheetin.  üCOMMANDÇissimilartoüSTATEMENTÇ.Theonlyexception isitscontentwillnotbestoredinthecurrentcell. Forsavingsomememory,eachtimeyoudefineafunction, thepointerofitstokensisbeingpushedintothe symboltableinsteadofstoringthesametokenstwice. So,ifyousay"@DEFINEF(X,Y)=3*x+4*y".Afterits execution,thesymboltablehasapointerthatwillbe freedbacktotheoperatingsystem.Whatwillhappen?I donotknow! êChangedisplayformatÇ: äDefaultformat:Ç üTEXT:Çleftjustified üSTATEMENT:Çleftjustified üFORMULAÇ, üCONSTANT:Çthenumberofdigitsafterthedecimal pointissix;rightjustifiedof calculatedresult,ifpossible,ablank spaceisaddedattherightmostplace. üWIDTH:Ç9characterspercolumn êOnlycalculatedresultandcolumnwidthcanbechanged.Ç üChangecolumnwidth:Ç -Selectmenuitem"Width"frommenutitle"Sheet" -Changethecolumncoordinateandcolumnwidthas desired. üChangecellformatÇ: -Selectmenuitem"Reformat"frommenutitle"Sheet" -Choosetheformat,decimalplaceandrangeofcells youwanttochange. -êNOTEÇ:YOUCANONLYREFORMATTHOSECELLSWHICH EXIST.ThatisbecauseofSparseMatrix.Aftera cellhasbeencreated,thecellpossesses attributes.Ifyouformatsomeemptycellsand insertsomethingintothosecellsafterthat,those cellsappearasdefault.Itisnotabug. êCalculationÇ: üAccuracyÇ:upto17digits üRangeÇ:-1E-37to1E+37 üArithmeticoperatorsÇ: "+","-","*","/","^",MOD üLogicaloperators:Ç AND,OR,NOT,"=","<>",">","<",">=","<=", "=>","=<" üBuilt-InfunctionsÇ: äMathÇ:SIN,COS,TAN,ASIN,ACOS,ATAN,LOG (älogarithmbase10Ç),EXP,LN(älogarithmbaseÇ äeÇ),ABS,INT(äintegerpartofarealnumberÇ), FRAC(äfractionpartofarealnumberÇ),SQR, SQRT,DATE(äcalculatetheJuliandays,3Ç äparameters,dd,mm,yyÇ),FACT(äfactorialÇ), RAD_DEG(äradiantodegreeÇ),DEG_RAD(ädegreetoÇ äradianÇ). äStatisticsÇ: AVERAGE,MEDIAN,STD(ästandarddeviationÇ) äMiscellaneousÇ: MAX,MIN,SUM ä FinanceÇ: NONE. äStringÇ: NONE. üPriorityÇ: äLowestÇ:-"+","-",OR -"*","/","^",AND,MOD -number,cellreference,variable,function call,NOT,"+","-"(unaryoperator) äHighestÇ:-Parenthesis üConstantsÇ:PIä(0.31415926535897932e+01)Ç,TODAYä(Juliandays whenyoupressTODAY,similartothefunction @TODAYonVIPprofessional.InLotus123, @TODAYwillberecalculatewhenyouloadthe file,butVIPwon't) Ç  êRecalculationÇ: äRecalculationorders:Ç üNaturalÇ:Recalculateeachcellintheordertheyare inserted.Itworkslikefirst-come-first- serve. üRow:ÇRecalculateeachrowintheascendingorder. üColumn:ÇRecalculateeachcolumnintheascending order. ♪①äManualrecalculation:Ç  Thespreadsheetstopsautomaticrecalculation.User hastopress<ALT-N>,<ALT-R>or<ALT-C>fornatural, roworcolumnrecalculation,where<ALT-N>meanspress <Alternate>keywithcharacterkey<N>simultaneously. äNotes:Ç  Rowandcolumnrecalculationmethodsarefaster thannaturalrecalculationmethod.ThatisduetoSparse Matrix.Eachcellislinkedwithwithitsleft,right, top,downcellstightly.Fornaturalrecalculation,each cellhastolocateindividually.Forrowandcolumn recalculation,eachcellcanmovetoitsnextcellby usingthelinkedpointer. êFileformatÇ: äHeaderÇ: -2bytesforversionnumber,currentversionis1.0 -268bytesforprint-dialoginformation(actually, only262bytesareused.Whenthegraphicpartis done,thisareawillbeusedforgraphinformation) -40bytesforwindowtitle.(39characterswitha nullcharacter) -2bytesforchecksumofthewindowtitletomake sureIamhandlingtherightworksheet. -256bytesforwidthofeachcolumns(youcannot displaycolumn0,butitisplannedtobeusedby theBASICinterpreterforinternaloperation). -2bytesforwindowtype(Itisuseless) -8bytesforcurrentwindowsize -4bytesfordisplayrangetoprow,topcolumn -4bytesforcurrentcellcursoraddress -2bytesforcurrentrecalculationmode äCellcontents:Ç -4bytesforcellrow,column -2bytesfordisplayattribute -2bytesfordecimalplace -2bytesfortokenslength -8bytesforcalculatedresult -tokenslengthbytesofactualtokens êPrintÇ:  Youcanprintyourworksheettoafileortoprinter. Theprintroutinewillprintthose columnsthatfitsonthemargins.Ifsomecolumnsonthe printrangearenotprintonthefirstpass,theywillbe printedonlaterpasses. êConclusionÇ:  Whatisnext?IplantoimplementtheCOPY,MOVEand ERASEcommandsonnextrelease.Somenewfunctionslike COLUMNandMATRIXshouldbedonealso.Whatarethey?Here are2examples: (äe.g.ÇIfyouhave"Quantity"incolumnBstarting fromrow1torow20,andyouhave"Price"on columnConthesamerowrange,andifyou wanttocalculatesubtotalforeachitem(each row),inLotus,youwilldothis: +b1*c1oncellD1 copyd1startingfromd2downtod20 ButifIfinishtheCOLUMNfunction,youcan dothisinonelineoncellD1: COLUMN(d1..d20,b1..b20*c1..c20) WhatdowegainbyusingCOLUMNfunctioninsteadof COPY?Speed!ByusingCOPYcommand,youhaveto recalculateasmanycellsasyoucopyto.Butusing COLUMNfunction,onlyoneformulawillbe recalculatedinaloop.Itshouldincreasethe recalculationperformance. äe.g.ÇMATRIX(a1..b3,a1..b3+d1..e3-3*(f1..g3)) Well,itworkssimilartoCOLUMNfunctionandnot onlymatrixaddition,subtraction,butalsomatrix multiplicationandinversewillbefunctioning.If Ifinishthosefunctions,thenlinearregression andsimultaneousequationscanbesolvedeasily. )  Well,thisprogramisnotfinishedyetanditneedsyour help(commentsandsuggestions)andsupport(êdonationÇ$10). Myaddressesare: Mr.Chor-mingLung 33GardenSt#3 Boston,MA02114 U.S.A. GEnie:LUNG CompuServe:72740,40 IwilllogonGEniemoreoftenthanCompuServe. üP.S.Ç Iamplanningtowriteasimplifiedversionfordesk accesory.Anyonewhodonateswillreceiveitwhenitis done.Ablankdiskwithnameandaddressonlabelis necessaryforthedeskaccessoryprogram.