Re: [Boost-users] mpl programming task

Subject: Re: [Boost-users] mpl programming task
From: peter_foelsche_at_[hidden]
Date: 2008-10-10 16:44:25

> #include <map>
> #include <set>
> 
> typedef std::map<size_t, size_t> CInt2IntMap;
> typedef std::set<size_t> CIntSet;
> 
> static CInt2IntMap convert(const CIntSet &_r)
> {	CInt2IntMap s;
> 	for (CIntSet::const_iterator p = _r.begin(); p != _r.end(); ++p)
> 		s.insert(std::make_pair(*p, s.size()));
> 	return s;
> }

Thanks Adam.

I found my own solution meanwhile.
I tried both, yours and mine.
Very slowly I'm getting used to this programming style (grin).
The compiler error messages are not very helpful.

Kind Regards
Peter

#include <boost/mpl/map.hpp>
#include <boost/mpl/set.hpp>
#include <boost/mpl/vector.hpp>
#include <iostream>
#include <boost/mpl/range_c.hpp>
#include <boost/mpl/at.hpp>
#include <boost/mpl/placeholders.hpp>
#include <boost/mpl/pair.hpp>
#include <boost/mpl/size.hpp>
#include <boost/mpl/accumulate.hpp>
#include <boost/mpl/transform.hpp>
#include <boost/mpl/insert.hpp>
#include <boost/mpl/equal_to.hpp>
#include <boost/mpl/equal.hpp>
#include <boost/mpl/assert.hpp>
#include <boost/mpl/for_each.hpp>

typedef boost::mpl::set<
        boost::mpl::int_<1>,
        boost::mpl::int_<3>
> CFirstSet;

template<typename CFirstSet>
struct CMyConvert:boost::mpl::accumulate<
        CFirstSet, 
        boost::mpl::map<>, 
        boost::mpl::lambda<
                boost::mpl::insert<
                        boost::mpl::_1,
                        boost::mpl::pair<
                                boost::mpl::_2,
                                boost::mpl::size<boost::mpl::_1>
			>
		>
	>::type
>::type
{
};

template<typename InputSeq>
struct CConvert : boost::mpl::transform<
        InputSeq,
        boost::mpl::range_c<
                long, 
                0, 
                boost::mpl::size<InputSeq>::value
	>,
        boost::mpl::pair<boost::mpl::_1, boost::mpl::_2>,
        boost::mpl::inserter<
                boost::mpl::map<>,
                boost::mpl::insert<boost::mpl::_1, boost::mpl::_2>
	>
>::type
{ 
};

typedef boost::mpl::map<
        boost::mpl::pair<
                boost::mpl::int_<3>,
                boost::mpl::integral_c<long, 0>
	>,
        boost::mpl::pair<
                boost::mpl::int_<1>,
                boost::mpl::integral_c<long, 1>
	>
> CMap1;

typedef boost::mpl::map<
        boost::mpl::pair<
                boost::mpl::int_<3>,
                boost::mpl::long_<0>
	>,
        boost::mpl::pair<
                boost::mpl::int_<1>,
                boost::mpl::long_<1>
	>
> CMap2;

template<typename T>
struct wrap
{
};

struct CPrintType
{	template<typename T>
        void operator()(wrap<T>) const
        {	std::cout << typeid(T).name() << "\n";
        }
};

int main(int , char **)
{	
        BOOST_MPL_ASSERT((
                boost::mpl::equal_to<
                        boost::mpl::at<
                                CConvert<CFirstSet>, 
                                boost::mpl::int_<1>
			>::type, 
                        boost::mpl::integral_c<long, 1> 
		>
        ));
        BOOST_MPL_ASSERT((
                boost::mpl::equal_to<
                        boost::mpl::at<
                                CConvert<CFirstSet>, 
                                boost::mpl::int_<3>
			>::type, 
                        boost::mpl::integral_c<long, 0> 
		>
        ));
        BOOST_MPL_ASSERT((
                boost::mpl::equal<
                        CConvert<CFirstSet>, 
                        CMap1
		>
        ));
        BOOST_MPL_ASSERT((
                boost::mpl::equal_to<
                        boost::mpl::at<
                                CMyConvert<CFirstSet>, 
                                boost::mpl::int_<1>
			>::type, 
                        boost::mpl::long_<1> 
		>
        ));
        BOOST_MPL_ASSERT((
                boost::mpl::equal_to<
                        boost::mpl::at<
                                CMyConvert<CFirstSet>, 
                                boost::mpl::int_<3>
			>::type, 
                        boost::mpl::long_<0> 
		>
        ));
        BOOST_MPL_ASSERT((
                boost::mpl::equal<
                        CMyConvert<CFirstSet>, 
                        CMap2
		>
        ));
        boost::mpl::for_each<
                CMyConvert<CFirstSet>,
                wrap<boost::mpl::_1>
	>(CPrintType());
        return 0;
}