[fpc-pascal] WHY compiler should be public?
Hi, First of all, I did some research and found this: http://free-pascal-general.1045716.n5.nabble.com/Compiler-Warning-Constructor-should-be-public-td2825747.html But that did not convince me. So here is my situation and question. I have the following case: TBase = class public constructor Create; //VER-0 end; TDerived = class(TBase) private constructor Create(param1); //VER-1 public constructor Create; reintroduce;//VER-0' constructor Create(param1, param2); //VER-2 constructor Create(param1, param2, param3); //VER-3 end; My purpose is that while using TDerived, only VER-2 and VER-3 of the constructors should be used, VER-0 and VER-1 are used INTERNALLY by VER-2 and VER-3 and should NOT be used publicly. As restricted by the "rule of OOP", you cannot make a method which is public in base class private in descendants, I plan to do the following： 1) reintroduce a Create (without param), which just throw an exception explaining that this MUST NOT be called directly. Meanwhile, use "inherited Create" internally in other versions of the constructors. 2) Make VER-1 private so that it cannot be called outside. Now the compiler throw a warning that constructor should be public. In the post I referred, Graeme explained that: == Your code is flawed. Object Pascal is quite clear regarding visibility rules. TObject has a Public constructor. You can only raise the visibility from there, not reduce visibility. Imagine how confusing it will be if you code was a library of some sorts and other developers had to use it. In a inherited class, you have public visibility to the constructor or some other method, and then suddenly in the descendant class the methods are hidden from the developer?? Not a good idea. == I don't understand this, because to me, the VER-1 constructor is introduced in TDerived, make it non-public does NOT reduce the visibility of VER-0 constructor, hence is not a violation of visibility rules, is it??? Thanks! Xiangrong ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Namespaces Support
With the new namespace support feature, will the fpc standard and base units be structured into packages? e.g types -> system.types; winsock -> windows.winsock; winmouse -> windows.winmouse 2013/10/24 Michael Van Canneyt > > > On Thu, 24 Oct 2013, Sven Barth wrote: > > Am 23.10.2013 16:34, schrieb Graeme Geldenhuys: >> Michael, how Delphi-compatible is it? In Delphi I can use (maybe >> not the best example) the reference >> Forms.Application and in the project compiler settings I can say if >> it is the VCL or the FMX namespace, so it >> knows at compile time which Application global variable to use. I >> personally haven't used namespaces, but during >> recent tiOPF discussions, such an example was presented to me - for >> use in a future tiOPF v4 branch (where >> namespaces will be used to differentiate between FMX, VCL etc. LCL >> and fpGUI probably too). >> >> Specifying default namespaces (which was AFAIK introduced with XE2) is >> not yet supported in FPC though it's definitely planned >> to add support for this. Otherwise namespace support should be compatible >> to Delphi 2009. >> > > Thanks for confirming my statements :) > > Michael. > ___ > fpc-pascal maillist - fpc-pascal@lists.freepascal.org > http://lists.freepascal.org/mailman/listinfo/fpc-pascal > ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Using arm-embedded-fpc
op 23-10-13 21:51, Florian Klämpfl schreef:
Am 23.10.2013 20:01, schrieb Michael Ring:
This article describes what build-id does:
https://fedoraproject.org/wiki/Releases/FeatureBuildId
your fix should get applied to trunk, the gnu-build section should end
up somewhere, best place is flash, it will not get used anyway.
Well, the best would be if it ended up nowhere because it eats only
flash memory.
Hi,
I modified t_embed.pas to not include that line in link.res :
.note.gnu.build-id : { *(.note.gnu.build-id) } >flash
But I'm unable to locate where that '--build-id' is generated for the
linker-commandline. If that is removed (only for arm-embedded ?), the
build-id will not be generated, so no wasted memory.
Regards,
Koenraad.
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Re: [fpc-pascal] DataSet.Locate: different behaviour between FPC 2.6.2 and 2.7.1 (rev. 2013/09/01)
silvioprog wrote / napísal(a): Hello, This morning, I compiled a code using FPC (Windows, rev. 2013/09/01), after that, my tests using dataset.locate has stopped. The Locate method locates record, even when it does not exists. The problem occurs only with varchar fields, in integer fields it works fine. In attachment I'm sending a small project to reproduce it. Here in my machine I made two tests, please see the log below: Result in FPC 2.6.2: test.exe output: N output: N Result in FPC 2.7.1: test.exe output: N output: Y Can you test it in FPC from trunk? I guess, that root of this problem is same like in bug report: http://bugs.freepascal.org/view.php?id=25016 For sorting/locating are used these string comparasion function: AnsiCompareText resp. AnsiCompareStr Can you test directly these functions in any simple string comparation test ? I expect, that these functions will return wrong results ? (may be that string encoding enters into play also? ... ) -Laco. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Namespaces Support
On Thu, 24 Oct 2013, Sven Barth wrote: Am 23.10.2013 16:34, schrieb Graeme Geldenhuys: Michael, how Delphi-compatible is it? In Delphi I can use (maybe not the best example) the reference Forms.Application and in the project compiler settings I can say if it is the VCL or the FMX namespace, so it knows at compile time which Application global variable to use. I personally haven't used namespaces, but during recent tiOPF discussions, such an example was presented to me - for use in a future tiOPF v4 branch (where namespaces will be used to differentiate between FMX, VCL etc. LCL and fpGUI probably too). Specifying default namespaces (which was AFAIK introduced with XE2) is not yet supported in FPC though it's definitely planned to add support for this. Otherwise namespace support should be compatible to Delphi 2009. Thanks for confirming my statements :) Michael.___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Namespaces Support
Am 23.10.2013 16:34, schrieb Graeme Geldenhuys: Michael, how Delphi-compatible is it? In Delphi I can use (maybe not the best example) the reference Forms.Application and in the project compiler settings I can say if it is the VCL or the FMX namespace, so it knows at compile time which Application global variable to use. I personally haven't used namespaces, but during recent tiOPF discussions, such an example was presented to me - for use in a future tiOPF v4 branch (where namespaces will be used to differentiate between FMX, VCL etc. LCL and fpGUI probably too). Specifying default namespaces (which was AFAIK introduced with XE2) is not yet supported in FPC though it's definitely planned to add support for this. Otherwise namespace support should be compatible to Delphi 2009. Regards, Sven ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Namespaces Support
Michael, how Delphi-compatible is it? In Delphi I can use (maybe not the best example) the reference Forms.Application and in the project compiler settings I can say if it is the VCL or the FMX namespace, so it knows at compile time which Application global variable to use. I personally haven't used namespaces, but during recent tiOPF discussions, such an example was presented to me - for use in a future tiOPF v4 branch (where namespaces will be used to differentiate between FMX, VCL etc. LCL and fpGUI probably too). How do you tell FPC which namespace a project is using? Regards, - Graeme - On Wednesday 23/10/2013 at 09:40, Michael Van Canneyt wrote: It already has. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
