int
list_delete_all (struct list *lst, char *str)
{
  struct node *garbage;	        // Something we want to delte
  struct node *current;         // For iterating lists
  struct node *previous;        // Also for iterating lists
 
  // Special case: The value is at the head
  while ((lst->head != NULL) && (strcmp (car (lst->head), str) == 0))
    {
      garbage = lst->head;
      lst->head = cdr (lst->head);
      free (garbage);
      --(lst->length);
    } // while

  // At this point, we know that the head of the list does not contain
  // str.  However, it may be empty.
  if (lst->head == NULL)
    {
      lst->tail = NULL;
      lst->length = 0;
      return 1;
    }

  // If we reach this point, the list is nonempty, and the head does not 
  // contain str.
  previous = lst->head;
  current = lst->head->next;

  // Keep going until we reach the end of the list
  while (current != NULL)
    {
      // If the current element contains str
      if (strcmp (car (current), str) == 0)
        {
          // Delete it
          garbage = current;
          current = cdr (current);
          free (garbage);
          set_cdr (previous, current);
          --(lst->length);
        }
      // If the current element does not contain str, go on
      else
        {
          previous = current;
          current = cdr (current);
        }
    } // while

  // Update the tail
  lst->tail = previous;

  // And we're done.
  return 1;
} // list_delete_all