list_merge.hpp

#ifndef PASTELSYS_LIST_MERGE_HPP
#define PASTELSYS_LIST_MERGE_HPP

#include "pastel/sys/list/list_merge.h"

namespace Pastel
{

    template <
        typename Settings,
        template <typename> class Customization,
        typename Less>
    List<Settings, Customization>& merge(
        List<Settings, Customization>& toSet, 
        List<Settings, Customization>& fromSet,
        Less less)
    {
        auto to = toSet.begin();
        auto toEnd = toSet.end();
        while (!fromSet.empty() && to != toEnd)
        {
            auto from = fromSet.begin();
            if (less(*from, *to))
            {
                toSet.splice(to, fromSet, from);
            }
            else
            {
                // In case of equality,
                // the element in 'toSet'
                // comes first.
                ++to;
            }
        }

        // Insert rest of fromSet.
        toSet.splice(toSet.end(), fromSet);

        return toSet;
    }

}

#endif