find.cpp

   1 // returns 1 if expr p contains expr q, otherweise returns 0
   2
   3 #include "stdafx.h"
   4 #include "defs.h"
   5
   6 int
   7 find(U *p, U *q)
   8 {
   9         int i;
  10
  11         if (equal(p, q))
  12                 return 1;
  13
  14         if (istensor(p)) {
  15                 for (i = 0; i < p->u.tensor->nelem; i++)
  16                         if (find(p->u.tensor->elem[i], q))
  17                                 return 1;
  18                 return 0;
  19         }
  20
  21         while (iscons(p)) {
  22                 if (find(car(p), q))
  23                         return 1;
  24                 p = cdr(p);
  25         }
  26
  27         return 0;
  28 }