Make your debug printing life easier

debug.hpp

#ifndef debug_macro
#define debug_macro

#if __cplusplus < 201402L
#error "debug header requires C++14 and above"
#endif

#include <iosfwd>
#include <utility>
#include <type_traits>

namespace detail {
	struct dblock {
		static int cnt;
		dblock() {++cnt;}
		~dblock() {--cnt;}
	};
	int dblock::cnt=0;

	template<typename It>
	struct rge {
		It b,e;
		rge(It b,It e) : b(b), e(e) {}
	};

	template<typename ...T, size_t ...Is>
	void print_tup(std::ostream &os, const std::tuple<T...> &t, std::index_sequence<Is...>) {
		os << '(';
		using swallow = int[];
		(void)swallow{0, ((os << (Is==0 ? "" : ", ") << std::get<Is>(t)),0)...};
		os << ')';
	}
}

template<typename T1,typename T2>
std::ostream& operator<<(std::ostream &os, const std::pair<T1,T2> &p) {
	return os << '(' << p.first << ", " << p.second << ')';
}

template<typename It>
std::ostream& operator<<(std::ostream &os,const detail::rge<It> &r) {
	os << '{';
	for(It i=r.b;i!=r.e;++i) {
	if(i!=r.b) os << ", ";
		os << *i;
	}
	return os << '}';
}

template<typename ...T>
std::ostream& operator<<(std::ostream &os, const std::tuple<T...> &t) {
	detail::print_tup(os,t,std::make_index_sequence<sizeof...(T)>());
	return os;
}

#define cerr for(int i=0;i<detail::dblock::cnt;i++) cerr << '\t'; cerr
#define dbg(val) "["#val": " << (val) << "]"
#define dbr(a,b,e) "["#a": " << detail::rge<common_type_t<decltype(b),decltype(c)>>(b,e) << "]"
#define dbfr(a) dbr(a,begin(a),end(a))

#endif