void examine_vertex(VertexType u, GraphType& g) { if (u == m_goal) throw found_goal(); }
void examine_vertex(int u, Graph_t& g) { if (u == m_goal) throw found_goal(); }
void examine_vertex(vertex_descriptor u, const filtered_grid&) { if (u == m_goal) throw found_goal(); }
void examine_vertex(Vertex u, Graph &/*g*/) { if (u == m_goal) { throw found_goal(); } }