Leitura de configuração em C++

config.h

template<typename Key, typename Value, typename AdderFunc>
void crack(config_holder<Key, Value> &config, const std::string &line, char delim, AdderFunc f) {
	auto b = std::begin(line);
	auto e = std::end(line);
	auto pos = line.find(delim);
	if( pos != std::string::npos ) {
		f(config, b, b+pos, e);
	}
}

//nossa AdderFunc
void default_adder(
	config_holder<std::string, std::string> &config, 
	iter_type b, iter_type m, iter_type e) {
	
	//b-m => key / m+1-e => value
	config.add_item( b, m, m+1, e );
}