exercise-4-1.hpp

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// ===-- chapter-4/exercise-4-1.hpp ----------------------- -*- C++ -*- --=== //
#ifndef EXERCISE_4_1
#define EXERCISE_4_1
 
#include "chapter-4-undefined_bool.hpp"
 
#include <boost/static_assert.hpp>
#include <boost/mpl/bool.hpp>
 
 
namespace exercise_4_1 {
using namespace chapter4;
 
template <typename E1, typename E2>
struct logical_or : logical_or<boost::mpl::bool_<E1::value>, E2> { };
 
template <typename E2>
struct logical_or<boost::mpl::true_, E2>
{
    static bool const value = true;
};
template <typename E2>
struct logical_or<boost::mpl::false_, E2>
{
    static bool const value = E2::value;
};
 
template <typename E1, typename E2>
struct logical_and : logical_and<boost::mpl::bool_<E1::value>, E2> { };
 
template <typename E2>
struct logical_and<boost::mpl::false_, E2>
{
    static bool const value = false;
};
template <typename E2>
struct logical_and<boost::mpl::true_, E2>
{
    static bool const value = E2::value;
};
 
} // namespace exercise_4_1
 
#endif // EXERCISE_4_1