Exercise 3-3 Abrahams & Gurtovoy

Turn T into T**** by using twice twice.

	#include <boost/type_traits/add_pointer.hpp>
	#include <boost/type_traits/is_same.hpp>
	#include <boost/static_assert.hpp>
	template <class UnaryMetaFunctionClass, class Arg>
	struct apply1
	: UnaryMetaFunctionClass::template apply<Arg>
	{};
	template <class F, class X>
	struct twice
	: apply1<F, typename apply1<F,X>::type>
	{};
	struct add_pointer_f
	{
	template <class T>
	struct apply : boost::add_pointer<T> {};
	};
	BOOST_STATIC_ASSERT((
	boost::is_same<
	twice<add_pointer_f,
	twice<add_pointer_f, int>::type>::type
	, int****
	>::value
	));
	int main()
	{
	return 0;
	}

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Exercise 3-1 of Abrahams & Gurtovoy

Turn vector_c<int,1,2,3> into a type sequence with elements (2,3,4) using transform.

	#include <boost/mpl/vector_c.hpp>
	#include <boost/mpl/plus.hpp>
	#include <boost/mpl/transform.hpp>
	#include <boost/mpl/equal.hpp>
	#include <boost/static_assert.hpp>
	typedef boost::mpl::vector_c<int,1,2,3> v_a;
	typedef boost::mpl::vector_c<int,1,1,1> v_b;
	typedef boost::mpl::vector_c<int,2,3,4> v_c0;
	struct plus_f
	{
	template <class T1, class T2>
	struct apply
	{
	typedef typename boost::mpl::plus<T1,T2>::type type;
	};
	};
	typedef typename boost::mpl::transform<v_a,v_b,plus_f>::type v_c1;
	BOOST_STATIC_ASSERT((
	boost::mpl::equal<v_c0,v_c1>::type::value
	));
	int main()
	{
	return 0;
	}

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