[vtk-developers] Introducing (optional) C++11 features in VTK

[Andrew Maclean]

(I have already shared this with Marcus)

To help the process along I did a cursory search and found these links:

 C++11 Detection with CMake: http://pageant.ghulbus.eu/?p=664

And down in the notes there is a comment from Rolf Eike Beer:

I have pushed a repository for this module online. I have incorporated some
of your changes, especially the 3 new tests.

git clone git://anongit.kde.org/scratch/dakon/cmake-cxx11



This could make a really good basis for the C++11 implementation.
I checked out the repository and it seems to work, read
CheckCX11features.cmake
it creates lots of variables called HAS_CXX11_* e.g. HAS_CXX11_LAMBDA

Regards
   Andrew


On Thu, Aug 21, 2014 at 7:24 AM, Jean-Christophe Fillion-Robin <
jchris.fillionr at kitware.com> wrote:

> +1
>
>
> On Tue, Aug 19, 2014 at 11:16 AM, Marcus D. Hanwell <
> marcus.hanwell at kitware.com> wrote:
>
>> Yes, and there are more extensive examples in the Qt project (for 5+),
>> and Boost where they both used the prefixed macro name approach. I can
>> get some of the basics in pretty quickly as I haven't heard much
>> opposition.
>>
>> Marcus
>>
>> On Mon, Aug 18, 2014 at 10:28 PM, Andrew Maclean
>> <andrew.amaclean at gmail.com> wrote:
>> > Brilliant! It looks as if ITK has already done a lot of this!
>> >
>> >
>> > Andrew
>> >
>> >
>> >
>> > On Tue, Aug 19, 2014 at 10:19 AM, Matt McCormick
>> > <matt.mccormick at kitware.com> wrote:
>> >>
>> >> VTK_OVERRIDE would be nice, and it would be nice to macros that are
>> >> similar to ITK.  Currently there is
>> >>
>> >>   ITK_OVERRIDE
>> >>   ITK_NOEXCEPT
>> >>   ITK_NULLPTR
>> >>
>> >>
>> >>
>> http://itk.org/gitweb?p=ITK.git;a=blob;f=Modules/Core/Common/include/itkMacro.h;h=aa4d40d7f5042eaf3c696af469d4cf0848239935;hb=HEAD#l121
>> >>
>> >>
>> >> Thanks,
>> >> Matt
>> >>
>> >> On Mon, Aug 18, 2014 at 7:25 PM, Marcus D. Hanwell
>> >> <marcus.hanwell at kitware.com> wrote:
>> >> > I am with David Gobbi and Ken. It would be a simple search and
>> replace
>> >> > once support for pre-C++11 compilers were dropped and the potential
>> >> > for unintended consequences is too great. Glad to see there is
>> general
>> >> > support, I should have included more on my reasoning, but didn't want
>> >> > to go into too much detail on implementation if there was little
>> >> > support for it.
>> >> >
>> >> > It sounds like there is, nullptr is definitely another piece of low
>> >> > hanging fruit. There is lots more that would be great to use, the
>> >> > language is evolving and it is important that we take advantage of
>> the
>> >> > parts that make sense.
>> >> >
>> >> > Marcus
>> >> >
>> >> > On Mon, Aug 18, 2014 at 6:43 PM, David Gobbi <david.gobbi at gmail.com>
>> >> > wrote:
>> >> >> Yes, I also believe that using "#define override" has the potential
>> to
>> >> >> cause problems.  Let's say that "override" appears as a variable
>> >> >> somewhere in code that someone brought into VTK and tested with a
>> >> >> C++11 compiler (this is legal, since "override" is not a keyword).
>> >> >> Then someone else tries compiling that code on C++03 where the
>> >> >> "#define override" is active.  All of a sudden, "override" is
>> replaced
>> >> >> by nothing anywhere it is used as a variable (or as any other kind
>> of
>> >> >> identifier).
>> >> >>
>> >> >>
>> >> >> On Mon, Aug 18, 2014 at 4:29 PM, Andrew Maclean
>> >> >> <andrew.amaclean at gmail.com> wrote:
>> >> >>> Hi Ken
>> >> >>>
>> >> >>> Good point, thanks for that.
>> >> >>>
>> >> >>> Andrew
>> >> >>>
>> >> >>>
>> >> >>> On Tue, Aug 19, 2014 at 8:25 AM, Moreland, Kenneth <
>> kmorel at sandia.gov>
>> >> >>> wrote:
>> >> >>>>
>> >> >>>> +1 for me too.
>> >> >>>>
>> >> >>>> However, my vote is actually to introduce things like VTK_OVERRIDE
>> >> >>>> and
>> >> >>>> VTK_FINAL until pre-C++11 compilers get abandoned. I find it
>> >> >>>> disconcerting
>> >> >>>> when libraries try to get cute with changing the behavior of (or
>> >> >>>> trying to
>> >> >>>> emulate) keywords with preprocessor macros. It can be pretty
>> >> >>>> confusing when
>> >> >>>> something goes wrong, and good luck if you have to use two
>> separate
>> >> >>>> projects
>> >> >>>> together that both tried to define preprocessor macros with
>> different
>> >> >>>> implementations.
>> >> >>>>
>> >> >>>> -Ken
>> >> >>>>
>> >> >>>>
>> >> >>>> From: Andrew Maclean <andrew.amaclean at gmail.com>
>> >> >>>> Reply-To: "andrew.amaclean at gmail.com" <andrew.amaclean at gmail.com>
>> >> >>>> Date: Monday, August 18, 2014 4:09 PM
>> >> >>>> To: VTK Developers <vtk-developers at vtk.org>, "Marcus D. Hanwell"
>> >> >>>> <marcus.hanwell at kitware.com>, Ben Boeckel <
>> ben.boeckel at kitware.com>,
>> >> >>>> Sean
>> >> >>>> McBride <sean at rogue-research.com>
>> >> >>>> Subject: [EXTERNAL] Re: [vtk-developers] Introducing (optional)
>> C++11
>> >> >>>> features in VTK
>> >> >>>>
>> >> >>>> +1! ... actually: ++1 :-)
>> >> >>>>
>> >> >>>> I would support this. To keep VTK relevant we need to be
>> introducing
>> >> >>>> these
>> >> >>>> features. Especially features like nullptr, unique_ptr etc.
>> >> >>>>
>> >> >>>> But I would not be happy at introducing more VTK defines like
>> >> >>>> VTK_OVERRIDE
>> >> >>>> and VTK_FINAL - unless absolutely necessary. I much prefer Sean's
>> >> >>>> idea of
>> >> >>>> using a modernise tool.
>> >> >>>>
>> >> >>>> Regards
>> >> >>>>    Andrew
>> >> >>>>
>> >> >>>>
>> >> >>>> On Tue, Aug 19, 2014 at 7:05 AM, <vtk-developers-request at vtk.org>
>> >> >>>> wrote:
>> >> >>>>>
>> >> >>>>>
>> >> >>>>> ---------- Forwarded message ----------
>> >> >>>>> From: "Marcus D. Hanwell" <marcus.hanwell at kitware.com>
>> >> >>>>> To: VTK Developers <vtk-developers at vtk.org>
>> >> >>>>> Cc:
>> >> >>>>> Date: Mon, 18 Aug 2014 13:45:37 -0400
>> >> >>>>> Subject: [vtk-developers] Introducing (optional) C++11 features
>> in
>> >> >>>>> VTK
>> >> >>>>> Hi,
>> >> >>>>>
>> >> >>>>> As we move forward, it would be great to get a feeling for
>> people's
>> >> >>>>> thoughts about integrating some components of C++11 optionally.
>> So
>> >> >>>>> if
>> >> >>>>> C++11 is available/enabled, there are several features we could
>> >> >>>>> enable
>> >> >>>>> optionally at compile time.
>> >> >>>>>
>> >> >>>>> A very simple example is that of the new override keyword, that
>> is
>> >> >>>>> used to indicate that a member function is overriding a virtual
>> >> >>>>> function. Using this can avoid mistakes where the signature
>> changes
>> >> >>>>> and derived classes are missed. It can be defined in a header
>> (empty
>> >> >>>>> on old compilers, override with recent compilers). Final is
>> similar,
>> >> >>>>> indicating that the virtual function cannot be overridden in
>> derived
>> >> >>>>> classes.
>> >> >>>>>
>> >> >>>>> This would introduce changes to the VTK coding style, where we
>> now
>> >> >>>>> use
>> >> >>>>> virtual for all virtual functions (first declaration, or
>> subsequent
>> >> >>>>> overrides). We could introduce this gradually for new code, even
>> >> >>>>> having one or two dashboards compiling this way would help spot
>> >> >>>>> simple
>> >> >>>>> errors such as an incorrect signature not actually overriding a
>> >> >>>>> function, but in fact declaring a new virtual for example.
>> >> >>>>>
>> >> >>>>> In these cases I would suggest simple naming, so VTK_OVERRIDE and
>> >> >>>>> VTK_FINAL would be used where a C++11 only code would simply use
>> the
>> >> >>>>> new keywords.
>> >> >>>>>
>> >> >>>>> Thoughts, objections? There are lots of other features, and I
>> know
>> >> >>>>> it
>> >> >>>>> will be a while before we can use them all but it would be great
>> to
>> >> >>>>> make a start with some of the easier ones that can improve code
>> >> >>>>> quality with little overhead.
>> >> >>>>>
>> >> >>>>> Marcus
>> >> >>>>>
>> >> >>>>>
>> >> >>>>>
>> >> >>>>> ---------- Forwarded message ----------
>> >> >>>>> From: Ben Boeckel <ben.boeckel at kitware.com>
>> >> >>>>> To: "Marcus D. Hanwell" <marcus.hanwell at kitware.com>
>> >> >>>>> Cc: VTK Developers <vtk-developers at vtk.org>
>> >> >>>>> Date: Mon, 18 Aug 2014 14:21:56 -0400
>> >> >>>>> Subject: Re: [vtk-developers] Introducing (optional) C++11
>> features
>> >> >>>>> in
>> >> >>>>> VTK
>> >> >>>>> On Mon, Aug 18, 2014 at 13:45:37 -0400, Marcus D. Hanwell wrote:
>> >> >>>>> > Thoughts, objections? There are lots of other features, and I
>> know
>> >> >>>>> > it
>> >> >>>>> > will be a while before we can use them all but it would be
>> great
>> >> >>>>> > to
>> >> >>>>> > make a start with some of the easier ones that can improve code
>> >> >>>>> > quality with little overhead.
>> >> >>>>>
>> >> >>>>> What about "= delete" for removing default assignment and copy
>> >> >>>>> constructors?
>> >> >>>>>
>> >> >>>>> --Ben
>> >> >>>>>
>> >> >>>>>
>> >> >>>>>
>> >> >>>>> ---------- Forwarded message ----------
>> >> >>>>> From: "Marcus D. Hanwell" <marcus.hanwell at kitware.com>
>> >> >>>>> To: Ben Boeckel <ben.boeckel at kitware.com>
>> >> >>>>> Cc: VTK Developers <vtk-developers at vtk.org>
>> >> >>>>> Date: Mon, 18 Aug 2014 14:29:10 -0400
>> >> >>>>> Subject: Re: [vtk-developers] Introducing (optional) C++11
>> features
>> >> >>>>> in
>> >> >>>>> VTK
>> >> >>>>> On Mon, Aug 18, 2014 at 2:21 PM, Ben Boeckel
>> >> >>>>> <ben.boeckel at kitware.com>
>> >> >>>>> wrote:
>> >> >>>>> > On Mon, Aug 18, 2014 at 13:45:37 -0400, Marcus D. Hanwell
>> wrote:
>> >> >>>>> >> Thoughts, objections? There are lots of other features, and I
>> >> >>>>> >> know it
>> >> >>>>> >> will be a while before we can use them all but it would be
>> great
>> >> >>>>> >> to
>> >> >>>>> >> make a start with some of the easier ones that can improve
>> code
>> >> >>>>> >> quality with little overhead.
>> >> >>>>> >
>> >> >>>>> > What about "= delete" for removing default assignment and copy
>> >> >>>>> > constructors?
>> >> >>>>> >
>> >> >>>>> Certainly, I think we should start out simple and then build it
>> out.
>> >> >>>>> If we have prototypes for a few of the most useful features that
>> can
>> >> >>>>> easily be encapsulated in compile time logic that will degrade to
>> >> >>>>> C++98 that would be great.
>> >> >>>>>
>> >> >>>>> Marcus
>> >> >>>>>
>> >> >>>>>
>> >> >>>>>
>> >> >>>>> ---------- Forwarded message ----------
>> >> >>>>> From: "Sean McBride" <sean at rogue-research.com>
>> >> >>>>> To: "Marcus D. Hanwell" <marcus.hanwell at kitware.com>, "VTK
>> >> >>>>> Developers"
>> >> >>>>> <vtk-developers at vtk.org>
>> >> >>>>> Cc:
>> >> >>>>> Date: Mon, 18 Aug 2014 16:50:12 -0400
>> >> >>>>> Subject: Re: [vtk-developers] Introducing (optional) C++11
>> features
>> >> >>>>> in
>> >> >>>>> VTK
>> >> >>>>> On Mon, 18 Aug 2014 13:45:37 -0400, Marcus D. Hanwell said:
>> >> >>>>>
>> >> >>>>> >As we move forward, it would be great to get a feeling for
>> people's
>> >> >>>>> >thoughts about integrating some components of C++11 optionally.
>> So
>> >> >>>>> > if
>> >> >>>>> >C++11 is available/enabled, there are several features we could
>> >> >>>>> > enable
>> >> >>>>> >optionally at compile time.
>> >> >>>>>
>> >> >>>>> +1 from me.
>> >> >>>>>
>> >> >>>>> nullptr is another one that can be made to work even on older
>> >> >>>>> compilers
>> >> >>>>> with some #define glue.
>> >> >>>>>
>> >> >>>>> Instead of creating a 'VTK_OVERRIDE', we could also use
>> 'override'
>> >> >>>>> as if
>> >> >>>>> we required C++11 and "#define override /* nothing */" as
>> >> >>>>> appropriate.  Then
>> >> >>>>> when C++11 really is the minimun requirement no big find/replace
>> is
>> >> >>>>> required.  Just a thought.
>> >> >>>>>
>> >> >>>>> PS: I already have dashboards building as C++11 and C++14.
>> >> >>>>>
>> >> >>>>> Cheers,
>> >> >>>>>
>> >> >>>>> --
>> >> >>>>> ____________________________________________________________
>> >> >>>>> Sean McBride, B. Eng                 sean at rogue-research.com
>> >> >>>>> Rogue Research                        www.rogue-research.com
>> >> >>>>> Mac Software Developer              Montréal, Québec, Canada
>> >> >>>>>
>> >> >>>>>
>> >> >>>>>
>> >> >>>>>
>> >> >>>>>
>> >> >>>>> ---------- Forwarded message ----------
>> >> >>>>> From: "Sean McBride" <sean at rogue-research.com>
>> >> >>>>> To: "Marcus D. Hanwell" <marcus.hanwell at kitware.com>, "VTK
>> >> >>>>> Developers"
>> >> >>>>> <vtk-developers at vtk.org>
>> >> >>>>> Cc:
>> >> >>>>> Date: Mon, 18 Aug 2014 17:05:38 -0400
>> >> >>>>> Subject: Re: [vtk-developers] Introducing (optional) C++11
>> features
>> >> >>>>> in
>> >> >>>>> VTK
>> >> >>>>> On Mon, 18 Aug 2014 16:50:12 -0400, Sean McBride said:
>> >> >>>>>
>> >> >>>>> >nullptr is another one that can be made to work even on older
>> >> >>>>> > compilers
>> >> >>>>> >with some #define glue.
>> >> >>>>> >
>> >> >>>>> >Instead of creating a 'VTK_OVERRIDE', we could also use
>> 'override'
>> >> >>>>> > as if
>> >> >>>>> >we required C++11 and "#define override /* nothing */" as
>> >> >>>>> > appropriate.
>> >> >>>>> >Then when C++11 really is the minimun requirement no big
>> >> >>>>> > find/replace is
>> >> >>>>> >required.  Just a thought.
>> >> >>>>>
>> >> >>>>> I hit send too fast...
>> >> >>>>>
>> >> >>>>> I also wanted to suggest looking at the clang-modernize tool,
>> which
>> >> >>>>> is "a
>> >> >>>>> standalone tool used to automatically convert C++ code written
>> >> >>>>> against old
>> >> >>>>> standards to use features of the newest C++ standard".
>> >> >>>>>
>> >> >>>>> <http://clang.llvm.org/extra/clang-modernize.html>
>> >> >>>>>
>> >> >>>>> Specifically, it can be used to automatically add 'override' and
>> >> >>>>> convert
>> >> >>>>> to 'nullptr':
>> >> >>>>>
>> >> >>>>> <http://clang.llvm.org/extra/AddOverrideTransform.html>
>> >> >>>>> <http://clang.llvm.org/extra/UseNullptrTransform.html>
>> >> >>>>>
>> >> >>>>> Cheers,
>> >> >> _______________________________________________
>> >> >> Powered by www.kitware.com
>> >> >>
>> >> >> Visit other Kitware open-source projects at
>> >> >> http://www.kitware.com/opensource/opensource.html
>> >> >>
>> >> >> Follow this link to subscribe/unsubscribe:
>> >> >> http://public.kitware.com/mailman/listinfo/vtk-developers
>> >> >>
>> >> > _______________________________________________
>> >> > Powered by www.kitware.com
>> >> >
>> >> > Visit other Kitware open-source projects at
>> >> > http://www.kitware.com/opensource/opensource.html
>> >> >
>> >> > Follow this link to subscribe/unsubscribe:
>> >> > http://public.kitware.com/mailman/listinfo/vtk-developers
>> >> >
>> >
>> >
>> >
>> >
>> > --
>> > ___________________________________________
>> > Andrew J. P. Maclean
>> >
>> > ___________________________________________
>> _______________________________________________
>> Powered by www.kitware.com
>>
>> Visit other Kitware open-source projects at
>> http://www.kitware.com/opensource/opensource.html
>>
>> Follow this link to subscribe/unsubscribe:
>> http://public.kitware.com/mailman/listinfo/vtk-developers
>>
>>
>
>
> --
> +1 919 869 8849
>



-- 
___________________________________________
Andrew J. P. Maclean

___________________________________________
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/vtk-developers/attachments/20140821/c88e5b5e/attachment-0002.html>