lambda表达式

 1 void Kv::load(const std::string &file) {
 2   this->clear();
 3   std::ifstream reader(file);
 4   assert(reader);
 5 
 6   if (reader.is_open()) {
 7     while (!reader.eof()) {
 8       std::string line;
 9       std::getline(reader, line);
10       if (line.empty()) continue;
11 
12       const auto parse = [](const std::string &str) {
13         std::string tmp, key, value;
14         for (size_t i = 0, len = str.length(); i < len; ++i) {
15           const char ch = str[i];
16           if (ch == ‘ ‘) {
17             if (i > 0 && str[i - 1] != ‘ ‘ && key.empty()) {
18               key = tmp;
19               tmp.clear();
20             }
21           }
22           else {
23             tmp.push_back(ch);
24           }
25           if (i == len - 1) {
26             value = tmp;
27           }
28         }
29         return std::make_pair(key, value);
30       };
31 
32       auto kv = parse(line);
33       this->add(kv.first, kv.second);
34     }
35     reader.close();
36   }
37 }