Function design: byref or global? - Ask for Help - AutoHotkey

Function design: byref or global? - posted in Ask for Help: I am designing a function which changes the values of multiple global variables ... Jumptocontent SignIn CreateAccount Sky Slate Blueberry Blackcurrant Watermelon Strawberry Orange Banana Apple Emerald Chocolate AutoHotkey Forums Members Search Advanced Searchsection: Thistopic Forums Members HelpFiles FacebookTwitter AutoHotkeyCommunity AutoHotkey AskforHelp ViewNewContent Functiondesign:byreforglobal? Startedby maxand ,Mar02201311:20AM Pleaselogintoreply 4repliestothistopic maxand Members 166posts Lastactive:Apr15201412:58PM Joined:03Apr2009 Iamdesigningafunctionwhichchangesthevaluesofmultipleglobalvariablesandamunclearwhethertopassvariables(arguments)toitusingbyref,ortodeclarethemasglobalvariableswithinthefunction.   Bothapproachescanachievethesameendresult.Thefirstexampleusesbyref: F1::  g_varA:=""  SetVarA(g_varA)  MsgBox,,,[2]g_varA=|%g_varA%|;result:"1"  SetVarA(byrefvarA){    varA:="1"    MsgBox,,,[1]g_varB=|%g_varB%|;result:""  } return Thesecondexampledispenseswithbyrefanddeclaresthevariable,withinthefunction,asglobal: F2::  g_varB:=""  SetVarB()  MsgBox,,,[2]g_varB=|%g_varB%|;result:"1"  SetVarB(){    globalg_varB    g_varB:="1"    MsgBox,,,[1]g_varB=|%g_varB%|;result:"1"    return  } return   Tokeepthingssimple,theseexampleschangeonlyoneglobalvariable;butsinceIintendtochangesetsofmultiplevariablesusingthisfunction,theuseofreturnattheendofthefunctionisinapplicableasitreturnsonlyonevalue.Likewise,passingbyvalueisoutasIneedtochangethevaluesoftheactualvariables.Usingassume-globalwouldsavesomecodehere.   Notethatitseemsfromtheabovethatwhenavariableispassedbyreference,thechangesmadetoitbythefunctionarenotapparentuntilthefunctioncompletesrunning,whereasifthevariableisdeclaredasglobal,changesmadetoitwithinthefunctionareimmediatelyevident.   UptillnowIhavereservedglobaldeclarationswithinfunctionsforconstantsusedthroughoutthescript.I'dreallyappreciatesomeadviceabouthowtodecidewhentopassbyreferenceandwhentodeclareglobal.Thanksinadvance.UsingAHKv1.0.48.05. #1 - Posted02March2013-11:20AM Backtotop Lexikos Administrators 9844posts AutoHotkeyFoundation Lastactive: Joined:17Oct2006 Ifyouwon'tbereusingthefunctiontomodifydifferentvariables(i.e.thosespecificglobalvariablesaretheonlyvariableswhichyou'llusethefunctionchange),youmayaswellassigntotheglobalvariablesdirectly.     whenavariableispassedbyreference,thechangesmadetoitbythefunctionarenotapparentuntilthefunctioncompletesrunning   False. F(v) F(ByRefp){    p:=123    ListVars    MsgBoxObservethatthefunctionhasn'tcompleted,butthechangetovisalreadyapparent. } InSetVarA,youhavealocalvariablecalledg_varB(i.e.youforgottodeclareitglobal). #2 - Posted02March2013-11:26AM http://ahkscript.org Backtotop maxand Members 166posts Lastactive:Apr15201412:58PM Joined:03Apr2009 ThanksLexikos.Youareright.Worse,Iscrewedupmycodeexample.Itshouldhavereadsomethinglikethis: F1::  A:=""  B:="" ;moresets  ;C:="";etc.  ;D:=""  SetVars(A,B)  MsgBox,,,[2]A=|%A%|,B=|%B%|;result:A=|1|,B=|1|  ;SetVars(C,D);etc.  SetVars(byrefX,byrefY){    X:="1"    Y:="1"    MsgBox,,,[1]A=|%A%|,B=|%B%|;result:A=||,B=||;appliesonlytoset[A,B]  } return  Lookingbackatthisproblemnow,byrefistheonlywaytogoifImeantopassmorethanonesetofvariablestoSetVars.E.g.,[A,B],[C,D],[E,F],etc.IfIdeclaredthemallglobalwithinthefunction,Iwouldhavetoremembertoincludeallofthemandthiswouldresultinunnecessaryduplicationwithinthefunction,defeatingitspurpose.Mybad. #3 - Posted02March2013-01:33PM Backtotop Lexikos Administrators 9844posts AutoHotkeyFoundation Lastactive: Joined:17Oct2006 Again,youforgottodeclareAandBglobalinsidethefunction. IfyouuseListVarsaboveMsgBoxinsidethefunction,itwillshowyouthatyouhavelocalAandBwhichareblank,andglobalAandBwhicharenot. #4 - Posted03March2013-12:17AM http://ahkscript.org Backtotop Scoox Members 194posts Lastactive:Jun09201703:34AM Joined:28Nov2010 Themainadvantageofglobalvariablesisthattheycanbeusedbyseveralfunctionsandyoudon'tneedtolisttheByRefvariableseachtimeyoucallthefunction,whichcanresultinverylonglinessometimes(thinkofafunctionwith10ByRefparameters).Also,codewhereafunctioniscalledwithinanotherfunctionusuallymeansthattheparametersmustbepassedthroughtheparentfunction,whichcanendupwithevenlongerparameterslists. Forsmallscripts(<500lines)IfindusingglobalsandGoSubisOK,butforlongerscriptsfunctions(vsGoSub)andfunctionparametersandconservativeuseofglobals(vsonlyglobals)makescodesignificantlyeasiertomanageandreducesthelikelihoodofbugs(e.g.imaginetworoutinesmodifyingthesameglobalvariableatthesametime). #5 - Posted26October2014-04:43AM RegJump()-JumptoregistrypathinRegedit HoverScroll()-HoverScroll()-Scrollcontrolswithoutfocus Backtotop BacktoAskforHelp Replytoquotedposts     Clear    AutoHotkeyCommunity →AutoHotkey →AskforHelp CommunityForumSoftwarebyIP.BoardLicensedto:AutoHotkeyFoundationLLC ChangeTheme IP.Board IP.BoardMobile Ortem English(USA) English(USA) Deutsch PrivacyPolicy Help SignIn  UseFacebook  UseTwitter Registernow! Usernameoremail: I'veforgottenmypassword ForumPassword Rememberme Thisisnotrecommendedforsharedcomputers Signinanonymously Don'taddmetotheactiveuserslist