CPP-TemplateMetaprog/exercise-3-3_8hpp_source.html

// ===-- chapter-3/exercise-3-3.hpp ----------------------- -*- C++ -*- --=== //

#ifndef EXERCISE_3_3

#define EXERCISE_3_3


#include "chapter-3-twice.hpp"


#include <boost/static_assert.hpp>


#include <boost/type_traits/add_pointer.hpp>


#include <boost/mpl/equal.hpp>

#include <boost/mpl/placeholders.hpp>

using namespace boost::mpl::placeholders;


namespace exercise_3_3 {

using namespace chapter3;


typedef twice<boost::add_pointer<_1>, int>::type double_pointer_int;

BOOST_STATIC_ASSERT((

    boost::mpl::equal< double_pointer_int, int** >::type::value));


typedef twice<boost::add_pointer<_1>,

              double_pointer_int>::type four_pointer_int;

BOOST_STATIC_ASSERT((

    boost::mpl::equal< four_pointer_int, int**** >::type::value));


} // namespace exercise_3_3


#endif // EXERCISE_3_3

chapter-3-twice.hpp
Define the twice metafunction for use in multiple exercises.

chapter3
Provide utilities availble to all Chapter 3 solutions.
Definition: chapter-3-twice.hpp:17

exercise_3_3
Encapsulate solution for Exercise 3-3.
Definition: exercise-3-3.hpp:35

exercise_3_3::BOOST_STATIC_ASSERT
BOOST_STATIC_ASSERT((boost::mpl::equal< double_pointer_int, int ** >::type::value))

exercise_3_3::double_pointer_int
twice< boost::add_pointer< _1 >, int >::type double_pointer_int
Used twice to add two pointers.
Definition: exercise-3-3.hpp:39

exercise_3_3::four_pointer_int
twice< boost::add_pointer< _1 >, double_pointer_int >::type four_pointer_int
Used twice twice to add four pointers.
Definition: exercise-3-3.hpp:45

chapter3::twice
Apply a metafunction to its own result.
Definition: chapter-3-twice.hpp:28