+struct MapObj;
+
+
+
+/* Try to move "actor" one step in direction "d" and handle the consequences:
+ * either the move succeeds, or another actor is encountered and hit (which leads
+ * to its lifepoint decreasing by one and potentially its death), or the target
+ * square is not passable and the move fails.
+ */
+extern uint8_t move_actor(struct World * world, struct MapObj * actor,
+ enum dir d);
+
+
+
+/* Wrapper for using move_actor() on the MapObj representing the player; updates
+ * the game log with appropriate messages on the move attempt and its results;
+ * turns over to turn_over() when finished.
+ */
+extern void move_player(struct World * world, enum dir d);
+
+
+
+/* Make player wait one turn, i.e. only update_log with a "you wait" message
+ * and turn control over to the enemy.
+ */
+extern void player_wait(struct World * world);
+
+
+
+/* Check if coordinate pos on (or beyond) map is accessible to map object
+ * movement.
+ */
+extern char is_passable(struct Map * map, struct yx_uint16 pos);
+