PK_ERROR_code_t    PK_EDGE_euler_split
(
--- received arguments ---
PK_EDGE_t          edge,        --- Edge to be split
PK_LOGICAL_t       forward,     --- New vertex is forward vertex

--- returned arguments ---
PK_VERTEX_t *const new_vertex,  --- New vertex create by split
PK_EDGE_t   *const new_edge     --- New edge created by split
)


This function splits an edge by adding a vertex.


edge can be of any type.  The forward argument determines whether the new
vertex becomes the forward or backward vertex of edge.

If edge is a ring, then only a new vertex is created and new_edge will be
PK_ENTITY_null.

The inverse of this function is PK_VERTEX_euler_merge_edges.