62 const std::string&
GetValue(
const std::string& variable_name)
const;
69 void SetValue(std::string variable_name, std::string value);
72 std::string&
operator[](
const std::string& variable_name);
78 auto empty()
const {
return vars_.empty(); }
81 auto size()
const {
return vars_.size(); }
83 using const_iterator = Map::const_iterator;
84 using iterator = const_iterator;
87 auto begin()
const {
return vars_.begin(); }
90 auto end()
const {
return vars_.end(); }