I sure have. Works fine. I think it's ok because I am only accessing class functions of the class. The memory won't be random as the compiler knows where the class functions (& methods for that matter) will be at compile time. It's only a classes data that gets allocated dynamically at runtime when classes ar instantiated. My classes don't have any data, and are never instantiated so it's fine. This sound right? I could have just fluked it though :/
Chris > -----Original Message----- > From: David Brennan [mailto:[EMAIL PROTECTED]] > Sent: Wednesday, 2 October 2002 5:10 p.m. > To: Multiple recipients of list delphi > Subject: RE: RE: RE: [DUG]: Class refs in classes > > > Umm, yeah. Have you tried running it yet? > > Looks like you are type casting your class reference as an TmyClass2 > instance and then accessing the class1 local variable. While > that might fool > the compiler I very much doubt it will fool the operating system into > believing that the random memory at the location > TmyClass2(Tmyclass2).class1 > is actually anything valid... > > Prepared to be proved wrong tho! ;-) > > David. > > > -----Original Message----- > > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]]On > > Behalf Of Chris Milham > > Sent: Wednesday, 2 October 2002 4:46 p.m. > > To: Multiple recipients of list delphi > > Subject: RE: RE: RE: [DUG]: Class refs in classes > > > > > > Got it working.. still doesn't look nice. > > How's this for wierd syntax?... > > > > TmyClass2(Tmyclass2).class1.doIt; > > > > :) > > > > Chris > > > > > > > -----Original Message----- > > > From: Myles Penlington [mailto:[EMAIL PROTECTED]] > > > Sent: Wednesday, 2 October 2002 4:31 p.m. > > > To: Multiple recipients of list delphi > > > Subject: RE: RE: [DUG]: Class refs in classes > > > > > > > > > No. You should be able to do this. It is in essence what > > > create does. Seems > > > like the compiler is getting confused - perhaps try some > > > syntax variations > > > to get it to work. > > > > > > Myles. > > > > > > > > > -----Original Message----- > > > From: Chris Milham [mailto:[EMAIL PROTECTED]] > > > Sent: Wednesday, 2 October 2002 4:29 p.m. > > > To: Multiple recipients of list delphi > > > Subject: RE: RE: [DUG]: Class refs in classes > > > > > > > > > Thanks David, > > > > > > The thing is, I don't want to have to instantiate anything. > > > Yes, I agree the local variable thing is a problem. Does > > > Delphi have the > > > equivalent of a class variable then? Variable is not the > > > right word.. what I > > > really want is a static ref to a class that can be contained > > > in another > > > class and accessed like a instance variable. Am I asking too > > > much? hmmm... > > > > > > Thanks, > > > > > > Chris > > > > > > > -----Original Message----- > > > > From: David Brennan [mailto:[EMAIL PROTECTED]] > > > > Sent: Wednesday, 2 October 2002 4:13 p.m. > > > > To: Multiple recipients of list delphi > > > > Subject: RE: [DUG]: Class refs in classes > > > > > > > > > > > > Chris, > > > > > > > > I'm guess that the problem isn't "accessing a class func > > > > through a ref to a > > > > class". I think it is that you are trying to access a local > > > > variable of a > > > > class without instantiating an instance of the class. The > > > > line with the > > > > problem is: > > > > > > > > Tmyclass2.class1.doIt; > > > > > > > > The problem is actually the part "Tmyclass2.class1". The > > > > other part (ie > > > > "class1.doIt") should be fine. The reason it doesn't work is > > > > that Tmyclass2 > > > > is a class reference and you can't access local > variables of a class > > > > reference (and class1 is a local variable). > > > > > > > > For this to be working you need to instantiate an instance of > > > > Tmyclass2 as > > > > follows... > > > > > > > > var > > > > LMyClass2 : TMyClass2; > > > > begin > > > > LMyClass2 := TMyClass2.Create; > > > > LMyClass2.Class1 := Tmyclass1; // Or any other Tmyclass1 > > > > descendant class. > > > > LMyClass2.Class1.doIt; > > > > ... > > > > end; > > > > > > > > (with appropriate try finally's etc added of course). > > > > > > > > Cheers, > > > > David. > > > > > > > > > -----Original Message----- > > > > > From: [EMAIL PROTECTED] > > > > [mailto:[EMAIL PROTECTED]]On > > > > > Behalf Of Chris Milham > > > > > Sent: Wednesday, 2 October 2002 3:45 p.m. > > > > > To: Multiple recipients of list delphi > > > > > Subject: [DUG]: Class refs in classes > > > > > > > > > > > > > > > Hi, > > > > > > > > > > I have been trying to make a hierarchical library of routines > > > > > using class procs/funcs. However Delphi 5 doesn't like me > > > > doing this. > > > > > What I have tried to do is as follows (hope this makes sense.. > > > > > only important bits included): > > > > > > > > > > type > > > > > Tmyclass1 = class > > > > > class procedure DoIt; > > > > > end; > > > > > Tmyclass1class = class of Tmyclass1; > > > > > Tmyclass2 = class > > > > > class1:Tmyclass1class; > > > > > end; > > > > > > > > > > procedure TForm1.Button1Click(Sender: TObject); > > > > > begin > > > > > Tmyclass1.doIt; // <- no probs with using a class proc > > > > > // Tmyclass2.class1.doIt; // *** Delphi compiler > doesn't like me > > > > > doing this: accessing a class func through a ref to a class. > > > > > end; > > > > > > > > > > class procedure Tmyclass1.DoIt; > > > > > begin > > > > > ShowMessage('Hello'); > > > > > end; > > > > > > > > > > > > > > > The error Delphi gives is: method identifier expected. > > > > > I can understand this (yes, I've read the help on it) > but why?? > > > > > I have tried numerous ways of getting this to work but had to > > > > > resort one option.... > > > > > I can work around this by simply having a class proc > in Tmyclass2 > > > > > that returns a Tmyclass1 class. > > > > > eg. > > > > > > > > > > Tmyclass2 = class > > > > > class function class1:TmyClass1class; > > > > > end; > > > > > > > > > > class function Tmyclass2.class1: TmyClass1class; > > > > > begin > > > > > Result := tmyclass1; > > > > > end; > > > > > > > > > > Then I can happily use this syntax: 'Tmyclass2.class1.doIt;' > > > > > This seems a not-too-nice way of doing what I want. > > > > > Any suggestions? Or am I trying to make Delphi be another > > > > language? ;) > > > > > > > > > > The other thing is: Is Delphi's optimiser smart > enough to convert > > > > > my 'class1' function in Tmyclass2 into a static > reference? ie. > > > > > am I going to have a performance hit because of > trying to do this > > > > > hierarchical library thing? > > > > > > > > > > TIA, > > > > > > > > > > Chris > > > > > > > > > > --- > > > > > > > > > > Chris Milham > > > > > Software Developer > > > > > MedTech Software Ltd. > > > > > Level M, 48 Market Place, Viaduct Basin, Auckland > > > > > Ph. +649 3559666 Extn. 714, Fax +649 3774231 > > > > > E-mail: [EMAIL PROTECTED] > > > > > Web: http://www.medtech-software.com > > > > > > > > > > > > > > > This e-mail and any attachments are intended only for > the person > > > > > to whom it is addressed and may contain privileged, > proprietary, > > > > > or other data protected from disclosure under > applicable law. If > > > > > you are not the addressee or the person responsible for > > > > > delivering this to the addressee you are hereby notified that > > > > > reading, copying or distributing this transmission is > prohibited. > > > > > If you have received this e-mail in error, please telephone us > > > > > immediately and remove all copies of it from your > system. Thank > > > > > you for your co-operation. > > > > > > > > > > <<Chris Milham.vcf>> > > > > > > > > > > > > > -------------------------------------------------------------- > > > > ------------- > > > > New Zealand Delphi Users group - Delphi List - > > > > [EMAIL PROTECTED] > > > > Website: http://www.delphi.org.nz > > > > To UnSub, send email to: [EMAIL PROTECTED] > > > > with body of "unsubscribe delphi" > > > > Web Archive at: > http://www.mail-archive.com/delphi%40delphi.org.nz/ > > > > > > > -------------------------------------------------------------- > > > ------------- > > > New Zealand Delphi Users group - Delphi List - > > > [EMAIL PROTECTED] > > > Website: http://www.delphi.org.nz > > > To UnSub, send email to: [EMAIL PROTECTED] > > > with body of "unsubscribe delphi" > > > Web Archive at: > http://www.mail-archive.com/delphi%40delphi.org.nz/ > > > -------------------------------------------------------------- > > > ------------- > > > New Zealand Delphi Users group - Delphi List - > > > [EMAIL PROTECTED] > > > Website: http://www.delphi.org.nz > > > To UnSub, send email to: [EMAIL PROTECTED] > > > with body of "unsubscribe delphi" > > > Web Archive at: > http://www.mail-archive.com/delphi%40delphi.org.nz/ > > > > > ------------------------------------------------------------------ > > --------- > > New Zealand Delphi Users group - Delphi List - > [EMAIL PROTECTED] > > Website: http://www.delphi.org.nz > > To UnSub, send email to: [EMAIL PROTECTED] > > with body of "unsubscribe delphi" > > Web Archive at: http://www.mail-archive.com/delphi%40delphi.org.nz/ > > -------------------------------------------------------------- > ------------- > New Zealand Delphi Users group - Delphi List - > [EMAIL PROTECTED] > Website: http://www.delphi.org.nz > To UnSub, send email to: [EMAIL PROTECTED] > with body of "unsubscribe delphi" > Web Archive at: http://www.mail-archive.com/delphi%40delphi.org.nz/ > --------------------------------------------------------------------------- New Zealand Delphi Users group - Delphi List - [EMAIL PROTECTED] Website: http://www.delphi.org.nz To UnSub, send email to: [EMAIL PROTECTED] with body of "unsubscribe delphi" Web Archive at: http://www.mail-archive.com/delphi%40delphi.org.nz/
