std::cout<<"["<<level_data<L>::letter<<"] in "<<file_path::relative(file)<<" : "<<line;
std::cout<<std::left<<std::setw(38)<<(std::string("[")+level_data<L>::letter+std::string("] in ")+std::experimental::filesystem::path(file).filename().string()+std::string(" : ")+std::to_string(line));