In file included from main.cpp:18:0:
game_database.h:81:7: error: 'DereferenceCompare' was not declared in this scope
       DereferenceCompare<GameObject, std::greater>
       ^~~~~~~~~~~~~~~~~~
game_database.h:81:50: error: template argument 2 is invalid
       DereferenceCompare<GameObject, std::greater>
                                                  ^
game_database.h:81:50: error: type/value mismatch at argument 3 in template parameter list for 'template<class _Key, class _Compare, class _Alloc> class std::set'
game_database.h:81:50: note:   expected a type, got 'greater'
game_database.h:82:5: error: template argument 2 is invalid
     >
     ^
game_database.h:82:5: error: template argument 4 is invalid
game_database.h:83:3: error: expected unqualified-id before '>' token
   > positions;
   ^
game_database.h:87:7: error: 'DereferenceCompare' was not declared in this scope
       DereferenceCompare<GameObject, std::greater>
       ^~~~~~~~~~~~~~~~~~
game_database.h:87:50: error: template argument 2 is invalid
       DereferenceCompare<GameObject, std::greater>
                                                  ^
game_database.h:87:50: error: type/value mismatch at argument 3 in template parameter list for 'template<class _Key, class _Compare, class _Alloc> class std::set'
game_database.h:87:50: note:   expected a type, got 'greater'
game_database.h:88:5: error: template argument 2 is invalid
     >
     ^
game_database.h:88:5: error: template argument 5 is invalid
game_database.h:89:3: error: expected unqualified-id before '>' token
   > names;
   ^
game_database.h: In member function 'void GameDatabase::Insert(ObjectId, std::__cxx11::string, size_t, size_t)':
game_database.h:25:5: error: 'positions' was not declared in this scope
     positions[{ x, y }].insert(item);
     ^~~~~~~~~
game_database.h:26:5: error: 'names' was not declared in this scope
     names[name].insert(item);
     ^~~~~
game_database.h:26:5: note: suggested alternative: 'name'
     names[name].insert(item);
     ^~~~~
     name
game_database.h: In member function 'void GameDatabase::Remove(ObjectId)':
game_database.h:34:9: error: 'positions' was not declared in this scope
       (*positions.find({ g->x, g->y })).second.erase(g);
         ^~~~~~~~~
game_database.h:35:9: error: 'names' was not declared in this scope
       (*names.find(g->name)).second.erase(g);
         ^~~~~
game_database.h:35:9: note: suggested alternative: 'rename'
       (*names.find(g->name)).second.erase(g);
         ^~~~~
         rename
game_database.h: In member function 'std::vector<GameObject> GameDatabase::DataByName(std::__cxx11::string) const':
game_database.h:43:15: error: 'names' was not declared in this scope
     auto it = names.find(name);
               ^~~~~
game_database.h:43:15: note: suggested alternative: 'name'
     auto it = names.find(name);
               ^~~~~
               name
game_database.h: In member function 'std::vector<GameObject> GameDatabase::DataByPosition(size_t, size_t) const':
game_database.h:56:15: error: 'positions' was not declared in this scope
     auto it = positions.find({ x, y });
               ^~~~~~~~~