[boost] Σχετ: Σχετ: [TypeSort] Automatic type sorting

20 Mar 2015

      That's fantastic! Thank you for your recommendation.
     Στις 4:32 μ.μ. Παρασκευή, 20 Μαρτίου 2015, ο/η Mathias Gaunard  έγραψε:

 On 20/03/2015 17:13, costis glynos wrote:
...
  On 20/03/2015 16:59, costis glynos wrote:
...
...
Hello,Is there any interest in a library which automatically sorts types from smallest to largest at compile time?The benefit would be the automatic Data Structure Alignment and potential improvement in performance.Foo foo_1; //normal
Foo foo_2; //using the TypeSort
output:
size of foo_1 = 48
size of foo_2 = 32 Kind Regards,
...
There is already a sort meta-function in Boost.MPL.
http://www.boost.org/doc/libs/1_57_0/libs/mpl/doc/refmanual/sort.html
Sweet! Thanks for bringing this to my attention.
You also need to use Boost.Fusion to make it into a tuple at the end, 
since this is what you want.

Here is an example:

#include 
#include 
#include 
#include 
#include 
#include <iostream>

int main()
{
  namespace mpl = boost::mpl;
  namespace fusion = boost::fusion;

  typedef mpl::vector types;
  typedef mpl::sortmpl::_1
                                    , mpl::sizeof_mpl::_2
                                    >
                    >::type sorted_types;
  typedef fusion::result_of::as_vector::type tuple;

  tuple t;
  std::cout << sizeof(t) << std::endl; // 8 instead of 12
}

This appears to work.

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