...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Returns a constant reference to this object as a basic_parser
.
basic_parser const& base() const;
This is used to pass a derived class where a base class is expected, to choose a correct function overload when the resolution would be ambiguous.