typedef struct s_int_list *int_list;
int_list list_new(void);
int_list int_list_add(int_list l, int i);
int_list int_list_del(int_list l, int i);
int int_list_search(int_list l, int i);
void int_list_traverse(int_list l, void (*process)(int i));
int int_list_isempty(int_list l);
void int_list_delete(int_list l);