[Insight-developers] The time has come for itkTypeTraits.h?

[Tom Vercauteren]

Agreed, we could even add boost TR1 implementation as a requirement
(i.e. not add it to ITK's repository  but use Cmake external project
for it) for compilers that do not support TR1.

Tom

On Fri, Nov 5, 2010 at 21:07, Bradley Lowekamp <blowekamp at mail.nih.gov> wrote:
> I dont' recall where the discussion of utilizing some parts of boost in ITK
> went. But this is the type of think I was thinking which may be a candidate
> for integration:
> http://www.boost.org/doc/libs/1_43_0/doc/html/boost_tr1.html
>
> On Nov 5, 2010, at 4:01 PM, kent williams wrote:
>
> G++ 4 and later has the std::tr1 type_traits, and you can include it with
> #include <tr1/type_traits> I believe.  There’s nothing I’ve seen in that
> header that would require anything except partial template specialization.
>  We can’t just glom that into ITK though, as it is licensed with some
> version of GPL.
>
> Most — if not all — modern compilers have some version of type_traits though
> it seems like there’s not much consistency in implementation — how you get
> access to them, what namespace the members are in.  I don’t know if there’s
> a really good way to handle this, frankly.
>
>
> On 11/5/10 2:19 PM, "Bradley Lowekamp" <blowekamp at mail.nih.gov> wrote:
>
> Kent,
>
> One minor point is the difference between tr1 and C++0x. "std::tr1" is an
> extension to standard template library which can be implemented with the
> current C++03. C++0x includes language extensions which many are not
> supported by compilers.
>
> So theoretically there could be an open source tr1 library someplace. Or at
> least some part of it. I think we should look at adding this extension as a
> whole instead of just a part or two.
>
> http://en.wikipedia.org/wiki/C%2B%2B_Technical_Report_1
>
> Brad
>
> On Nov 5, 2010, at 3:11 PM, kent williams wrote:
>
> In trying to replace the use of typeids in ITK with compile-time code based
> on Template Metaprogramming, I've run into this issue: The job would be a
> whole lot easier if we had access to the C++0x type_traits header.
>
> What would it take to make this a possibility?
>
> In CMakeLists.txt:
>
> CHECK_INCLUDE_FILES(type_traits HAVE_TYPE_TRAITS)
>
> itkTypeTraits.h:
>
> #ifndef __itkTypeTraits_h
> #define __itkTypeTraits_h
> #include "itkConfigure.h"
>
> #if defined(HAVE_TYPE_TRAITS)
> #include <type_traits>
> #else
> // implement needed type_traits macros
> namespace std
> {
>   template<typename _Tp, _Tp __v>
>     struct integral_constant
>     {
>       static const _Tp                      value = __v;
>       typedef _Tp                           value_type;
>       typedef integral_constant<_Tp, __v>   type;
>     };
>   typedef integral_constant<bool, true>     true_type;
>   typedef integral_constant<bool, false>    false_type;
>
> // e.g. the is_same relation
> template<typename, typename>
> struct is_same : public false_type { };
>
> template<typename _Tp>
> struct is_same<_Tp, _Tp>  : public true_type { };
>
> }
> #endif
>
> _______________________________________________
> Powered by www.kitware.com <http://www.kitware.com>
>
> Visit other Kitware open-source projects at
> http://www.kitware.com/opensource/opensource.html
>
> Kitware offers ITK Training Courses, for more information visit:
> http://kitware.com/products/protraining.html
>
> Please keep messages on-topic and check the ITK FAQ at:
> http://www.itk.org/Wiki/ITK_FAQ
>
> Follow this link to subscribe/unsubscribe:
> http://www.itk.org/mailman/listinfo/insight-developers
>
> ========================================================
>
> Bradley Lowekamp
>
> Lockheed Martin Contractor for
>
> Office of High Performance Computing and Communications
>
> National Library of Medicine
>
> blowekamp at mail.nih.gov
>
>
>
>
>
> _______________________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at
> http://www.kitware.com/opensource/opensource.html
>
> Kitware offers ITK Training Courses, for more information visit:
> http://kitware.com/products/protraining.html
>
> Please keep messages on-topic and check the ITK FAQ at:
> http://www.itk.org/Wiki/ITK_FAQ
>
> Follow this link to subscribe/unsubscribe:
> http://www.itk.org/mailman/listinfo/insight-developers
>
>