group_list
| T_GROUPING group_list T_NL
group_list : T_NUMBER
| group_list T_SEMI T_NUMBER
static group_t *group_list;
for (group = group_list; group != NULL; group = group->next) {
for (group = group_list; group != NULL; group = group->next) {
for (group = group_list; group != NULL; group = group->next) {
group->next = group_list;
group_list = group;
group_t *group = group_list;
group_list = NULL;
struct group_list *g;
g = (struct group_list *)malloc(sizeof (struct group_list));
struct group_list *g;
struct group_list *next;
static struct group_list *groups[GRPTABSIZE]; /* group table */