first commit

third_party/yaml-cpp/src/null.cpp

@@ -0,0 +1,10 @@
+#include "yaml-cpp/null.h"
+
+namespace YAML {
+_Null Null;
+
+bool IsNullString(const std::string& str) {
+  return str.empty() || str == "~" || str == "null" || str == "Null" ||
+         str == "NULL";
+}
+}  // namespace YAML