Re: [fpc-pascal] Classes with abstract methods
On Mon, 14 Jan 2008, Damien Gerard wrote: With fpc you can get myfile.pas(77,47) Warning: Constructing a class with abstract methods I just would like to know why it is allowed to build classes with abstract methods. AFIK it is different from other compilers and it is a bit strange for me. Delphi gives exactly the same warning. It is allowed to create such instances: as long as you don't call any of the abstract methods, there will be no problem. Michael. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Classes with abstract methods
On Jan 14, 2008, at 10:27 AM, Michael Van Canneyt wrote: On Mon, 14 Jan 2008, Damien Gerard wrote: With fpc you can get myfile.pas(77,47) Warning: Constructing a class with abstract methods I just would like to know why it is allowed to build classes with abstract methods. AFIK it is different from other compilers and it is a bit strange for me. Delphi gives exactly the same warning. I don't remember that. It is allowed to create such instances: as long as you don't call any of the abstract methods, there will be no problem. Is there a way to abort the compilation in this cases instead of a warning ? -- Damien Gerard [EMAIL PROTECTED] Le temps n'a pas d'importance. Seul le code est important -- (f00ty) ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Classes with abstract methods
On Mon, 14 Jan 2008, Damien Gerard wrote: On Jan 14, 2008, at 10:27 AM, Michael Van Canneyt wrote: On Mon, 14 Jan 2008, Damien Gerard wrote: With fpc you can get myfile.pas(77,47) Warning: Constructing a class with abstract methods I just would like to know why it is allowed to build classes with abstract methods. AFIK it is different from other compilers and it is a bit strange for me. Delphi gives exactly the same warning. I don't remember that. D:\Tempdcc32 unit1 Borland Delphi Version 15.0 Copyright (c) 1983,2002 Borland Software Corporation Unit1.pas(32) Warning: Constructing instance of 'TStrings' containing abstract method 'TStrings.Clear' Unit1.pas(32) Warning: Constructing instance of 'TStrings' containing abstract method 'TStrings.Delete' Unit1.pas(32) Warning: Constructing instance of 'TStrings' containing abstract method 'TStrings.Insert' Unit1.pas(32) Hint: Value assigned to 'T' never used Unit1.pas(36) 37 lines, 0.11 seconds, 475 bytes code, 8 bytes data. It is allowed to create such instances: as long as you don't call any of the abstract methods, there will be no problem. Is there a way to abort the compilation in this cases instead of a warning ? Currently not. Michael. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Classes with abstract methods
On Jan 14, 2008, at 11:00 AM, Graeme Geldenhuys wrote: On 14/01/2008, Michael Van Canneyt [EMAIL PROTECTED] wrote: Is there a way to abort the compilation in this cases instead of a warning ? Currently not. If you want to be that strict, then use Interfaces instead of Abstract classes. Indeed I should do this. Thanks -- Damien Gerard [EMAIL PROTECTED] Le temps n'a pas d'importance. Seul le code est important -- (f00ty) ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Classes with abstract methods
On Jan 14, 2008, at 10:53 AM, Michael Van Canneyt wrote: On Mon, 14 Jan 2008, Damien Gerard wrote: On Jan 14, 2008, at 10:27 AM, Michael Van Canneyt wrote: On Mon, 14 Jan 2008, Damien Gerard wrote: With fpc you can get myfile.pas(77,47) Warning: Constructing a class with abstract methods I just would like to know why it is allowed to build classes with abstract methods. AFIK it is different from other compilers and it is a bit strange for me. Delphi gives exactly the same warning. I don't remember that. D:\Tempdcc32 unit1 Borland Delphi Version 15.0 Copyright (c) 1983,2002 Borland Software Corporation Unit1.pas(32) Warning: Constructing instance of 'TStrings' containing abstract method 'TStrings.Clear' Unit1.pas(32) Warning: Constructing instance of 'TStrings' containing abstract method 'TStrings.Delete' Unit1.pas(32) Warning: Constructing instance of 'TStrings' containing abstract method 'TStrings.Insert' Unit1.pas(32) Hint: Value assigned to 'T' never used Unit1.pas(36) 37 lines, 0.11 seconds, 475 bytes code, 8 bytes data. Yes I trust you don't wory, just my mind is playing with me :) It is allowed to create such instances: as long as you don't call any of the abstract methods, there will be no problem. Is there a way to abort the compilation in this cases instead of a warning ? Currently not. Thanks -- Damien Gerard [EMAIL PROTECTED] Le temps n'a pas d'importance. Seul le code est important -- (f00ty) ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Classes with abstract methods
On 14/01/2008, Michael Van Canneyt [EMAIL PROTECTED] wrote: Is there a way to abort the compilation in this cases instead of a warning ? Currently not. If you want to be that strict, then use Interfaces instead of Abstract classes. - Regards, - Graeme - ___ fpGUI - a cross-platform Free Pascal GUI toolkit http://opensoft.homeip.net/fpgui/ ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Classes with abstract methods
Graeme Geldenhuys wrote: On 14/01/2008, Michael Van Canneyt [EMAIL PROTECTED] wrote: Is there a way to abort the compilation in this cases instead of a warning ? Currently not. If you want to be that strict, then use Interfaces instead of Abstract classes I always found (and still do in C#) that interfaces are good for forcing structure but bad for forcing good inheritance trees. The good thing about classes with abstract methods is that they form a point for inheritance. Interfaces - well, I regularly use interfaces to create a common structure, e.g. an API that will have both a webservice interface and a local interface. The common API is an interface in a separate assembly, used on both client and server to implement an identical API (client code can then link to either the local API or the webservice via a client that implements the same interface.) DotNet also makes reflection (RTTI) quite useful with interfaces too, but I digress. The point is that the webservice class, the client and the local API that the webservice wraps all implement the interface (the webservice usually just delegates responsibility to an internal instance), but none of them inherit from each other. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Classes with abstract methods
It is allowed to create such instances: as long as you don't call any of the abstract methods, there will be no problem. Is there a way to abort the compilation in this cases instead of a warning ? Currently not. You can abort compilation in case of any warning with the -Sew option. The same goes for note or hint with -Sen or -Seh, but those are only usefull for compiler tests. Peter ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Classes with abstract methods
On Mon, 14 Jan 2008, Peter Vreman wrote: It is allowed to create such instances: as long as you don't call any of the abstract methods, there will be no problem. Is there a way to abort the compilation in this cases instead of a warning ? Currently not. You can abort compilation in case of any warning with the -Sew option. The same goes for note or hint with -Sen or -Seh, but those are only usefull for compiler tests. The problem with this mechanism is that if you have another warning which occurs first, that will stop your compilation, you'll never get to the abstract warning... Michael. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Classes with abstract methods
On 14 Jan 2008, at 14:43, Damien Gerard wrote: On Jan 14, 2008, at 11:55 AM, Michael Van Canneyt wrote: The problem with this mechanism is that if you have another warning which occurs first, that will stop your compilation, you'll never get to the abstract warning... I agree. May be a new option in a future release of fpc ? :) It would be nice to have a switch to do it. There is already a feature request for the ability to turn off/on certain warnings in Mantis. Upgrading certain warnings (and hints/ notes) to errors is quite related. It should be quite doable for an outsider to implement this sort functionality, but until now no one has volunteered yet. Jonas ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Classes with abstract methods
On Jan 14, 2008, at 11:55 AM, Michael Van Canneyt wrote: On Mon, 14 Jan 2008, Peter Vreman wrote: It is allowed to create such instances: as long as you don't call any of the abstract methods, there will be no problem. Is there a way to abort the compilation in this cases instead of a warning ? Currently not. You can abort compilation in case of any warning with the -Sew option. The same goes for note or hint with -Sen or -Seh, but those are only usefull for compiler tests. The problem with this mechanism is that if you have another warning which occurs first, that will stop your compilation, you'll never get to the abstract warning... I agree. May be a new option in a future release of fpc ? :) It would be nice to have a switch to do it. -- Damien Gerard [EMAIL PROTECTED] Le temps n'a pas d'importance. Seul le code est important -- (f00ty) ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Classes with abstract methods
On Jan 14, 2008, at 2:59 PM, Jonas Maebe wrote: On 14 Jan 2008, at 14:43, Damien Gerard wrote: On Jan 14, 2008, at 11:55 AM, Michael Van Canneyt wrote: The problem with this mechanism is that if you have another warning which occurs first, that will stop your compilation, you'll never get to the abstract warning... I agree. May be a new option in a future release of fpc ? :) It would be nice to have a switch to do it. There is already a feature request for the ability to turn off/on certain warnings in Mantis. Upgrading certain warnings (and hints/ notes) to errors is quite related. It should be quite doable for an outsider to implement this sort functionality, but until now no one has volunteered yet. I see. I will see what I can do next month. -- Damien Gerard [EMAIL PROTECTED] Le temps n'a pas d'importance. Seul le code est important -- (f00ty) ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Classes with abstract methods
The problem with this mechanism is that if you have another warning which occurs first, that will stop your compilation, you'll never get to the abstract warning... I agree. May be a new option in a future release of fpc ? :) It would be nice to have a switch to do it. There is already a feature request for the ability to turn off/on certain warnings in Mantis. Upgrading certain warnings (and hints/ notes) to errors is quite related. It should be quite doable for an outsider to implement this sort functionality, but until now no one has volunteered yet. Upgrade a warning to error can already be done by editing (replace a W with an E) the errore.msg yourself and pass the modified errore.msg to the compiler with -Fr. Peter ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Classes with abstract methods
On 14 Jan 2008, at 15:45, Peter Vreman wrote: There is already a feature request for the ability to turn off/on certain warnings in Mantis. Upgrading certain warnings (and hints/ notes) to errors is quite related. It should be quite doable for an outsider to implement this sort functionality, but until now no one has volunteered yet. Upgrade a warning to error can already be done by editing (replace a W with an E) the errore.msg yourself and pass the modified errore.msg to the compiler with -Fr. You can similarly downgrade a warning to a note or hint by changing the W with a N or H, but the problem is that you have to redo this for each release. Jonas ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
