char *(*interpret_move)(game_state *state, game_ui *ui, game_drawstate *ds,
int x, int y, int button);
game_state *(*execute_move)(game_state *state, char *move);
char *(*interpret_move)(game_state *state, game_ui *ui, game_drawstate *ds,
int x, int y, int button);
game_state *(*execute_move)(game_state *state, char *move);