vertex_type
typedef typename vertex_type::value_type value_type;
m_vertices.push_back(vertex_type(value_type(x),
vertex_type& v = m_vertices[idx];
vertex_type& v = m_vertices[idx];
vertex_type t = m_vertices[v1];
const vertex_type& v = m_vertices[idx];
const vertex_type& v = (*m_container)[m_index++];
const vertex_type& v = (*m_container)[m_index--];
m_src_vertices.modify_last(vertex_type(m_start_x = x, m_start_y = y));
m_src_vertices.add(vertex_type(x, y));
vertex_type& prev = vs[n-1];
vertex_type& last = vs[n];
vertex_type& v = m_src_vertices[m_cur_vertex++];