LT.c

// Start at subject listItem and traverse the key as an association to a new listItem
// - key is also a listItem reference and its binary address is used as the traversal path
// - subject and key (all list-item references are ints starting at item 0)
// - if key is 0 the subject is returned unchanged, key 1 and 2 are the two single-iteration traversals
item listTraverse(item subject, item key) {
	if(key++ > 0) {
		int i,j;
		for(i = 1; i <= key >> 1; i <<= 1) {
			j = subject * 3;
			if(key & i) j++;
			if(space[j] == 0) space[j] = listInsert();
			subject = space[j];
		}
	}
	return subject;
}