/// Compare two position objects.
inline bool
operator== (const position& pos1, const position& pos2)
/// Compare two position objects.
inline bool
operator== (const position& pos1, const position& pos2)
/// Compare two location objects.
inline bool
operator== (const location& loc1, const location& loc2)
/// Compare two location objects.
inline bool
operator== (const location& loc1, const location& loc2)