#include <iostream>
#include <utility>
#include <list>

template<class T>
struct traits_interval
{
	typedef T value_type;
};

template<class T>
class interval
{
	public :
		typedef typename traits_interval<T>::value_type value_type;
		interval() : pinterval(std::make_pair(T(), T())) {}
		interval(const T& start, const T& end) : pinterval(std::make_pair(start, end)){}
		
		T& start() { return pinterval.first; }
		const T& start() const { return pinterval.first; }
		
		T& end() { return pinterval.second; }
		const T& end() const { return pinterval.second; }
		
		friend bool operator<(const interval<T>& first, const interval<T>& second)
		{
			if(first.start() == second.start()) return first.end() < second.end();
			return first.start() < second.start();
		}

	private :
		std::pair<T, T> pinterval;
};

namespace
{
	typedef std::list<interval<int>> linterval;
	typedef std::list<interval<int>>::iterator iinterval; 
}

class merge_overlapping_intervals
{
	public :
		void operator()(std::list<interval<int>>& intervals)
		{
			intervals.sort();
			iinterval inext(intervals.begin()); ++inext;
			for(iinterval i(intervals.begin()), iend(intervals.end()); inext != iend;)
			{
				if((i->end() > inext->start()))
				{
					if(i->end() >= inext->end()) intervals.erase(inext++);
					else if(i->end() < inext->end())
					{ i->end() = inext->end(); intervals.erase(inext++); }
				}
				else { ++i; ++inext; }
			}
		}
};

int main()
{
	linterval intervals{interval<int>(5, 8), interval<int>(3, 6), interval<int>(1, 4), interval<int>(8, 9)};
	merge_overlapping_intervals()(intervals);
	for(interval<int> i : intervals) std::cout << " {" << i.start() << ", " << i.end() << "}";
	
	std::cout << "\n";
	linterval intervals_2{interval<int>(3, 4), interval<int>(3, 6), interval<int>(1, 4)};
	merge_overlapping_intervals()(intervals_2);
	for(interval<int> i : intervals_2) std::cout << " {" << i.start() << ", " << i.end() << "}";

	std::cout << "\n";
	linterval intervals_3{interval<int>(1, 4), interval<int>(1, 6), interval<int>(1, 4)};
	merge_overlapping_intervals()(intervals_3);
	for(interval<int> i : intervals_3) std::cout << " {" << i.start() << ", " << i.end() << "}";
	
	std::cout << "\n";
	linterval intervals_4{interval<int>(3, 6), interval<int>(1, 2), interval<int>(7, 8)};
	merge_overlapping_intervals()(intervals_4);
	for(interval<int> i : intervals_4) std::cout << " {" << i.start() << ", " << i.end() << "}";

	return 0;
}

Line 37: error: '>>' should be '> >' within a nested template argument list
compilation terminated due to -Wfatal-errors.