int get_world_dimens ( struct world *world, char *str, int lineno );
int get_eden_dimens ( struct world *world, char *str, int lineno );
int get_plant_energy ( struct world *world, char *str, int lineno );
int get_reproduction_threshold ( struct world *world, char *str, int lineno );
struct animal *get_animal_specs ( char *str, int lineno );
char *fetch_line_aux ( char *buf, int buflen,  FILE *stream, int *lineno );
int read_wdf ( struct world *world );
int write_wdf ( struct world *world, char *filename );