你能用Boost.Regex解析一个流吗？

#include<boost/regex.hpp>
#include<iostream>
#include <sstream>
#include<string>

int main() {
  std::stringstream input_stream;
  input_stream << "This is a test string.";

  std::string line;
  boost::regex pattern("(\\w+)");
  boost::smatch matches;

  while (std::getline(input_stream, line)) {
    if (boost::regex_search(line, matches, pattern)) {
      std::cout << "Matched word: "<< matches[1]<< std::endl;
    }
  }

  return 0;
}