Function ToLower

lib/yamlcpp/src/convert.cpp:9–9

bool IsLower(char ch) { return 'a' <= ch && ch <= 'z'; }
bool IsUpper(char ch) { return 'A' <= ch && ch <= 'Z'; }
char ToLower(char ch) { return IsUpper(ch) ? ch + 'a' - 'A' : ch; }

std::string tolower(const std::string& str) {
  std::string s(str);