1typedef struct x
2{
3  struct x *type;
4  struct x *chain;
5  struct x *value;
6} *tree;
7
8int
9func (new, old)
10     register tree new, old;
11{
12  if (old->type == 0 || new->type == 0)
13    {
14      register tree t = old->type;
15      if (t == 0)
16	t = new->type;
17      for (; t; t = t->chain )
18	if (t->value)
19	  return 1;
20    }
21  return 0;
22}
23