void actlist_insert(actlist_t*a, point_t p1, point_t p2, segment_t*s);
void actlist_delete(actlist_t*a, segment_t*s);
void actlist_swap(actlist_t*a, segment_t*s1, segment_t*s2);
void actlist_insert(actlist_t*a, point_t p1, point_t p2, segment_t*s);
void actlist_delete(actlist_t*a, segment_t*s);
void actlist_swap(actlist_t*a, segment_t*s1, segment_t*s2);