44 	int st_top;  member
57 	sp->st_top = -1;  in stack_new()
70 		for (i = 0; i <= sp->st_top; i++)  in stack_free()
80 	assert(sp->st_top >= 0);  in stack_pop()
82 	return (sp->st_data[sp->st_top--]);  in stack_pop()
88 	if (sp->st_top == -1)  in stack_peek()
91 	return (sp->st_data[sp->st_top]);  in stack_peek()
97 	sp->st_top++;  in stack_push()
99 	if (sp->st_top == sp->st_nument) {  in stack_push()
105 	sp->st_data[sp->st_top] = data;  in stack_push()
111 	return (sp->st_top + 1);  in stack_level()