ifclass StringTree1
static void addToStringTree(StringTree1 tree, L<S> tokC) {
  if (empty(tokC)) { tree.leaf = true; ret; }
  S s = first(tokC);
  StringTree1 t = tree.getOrAdd(s);
  addToStringTree(t, dropFirst(tokC));
}
endif

ifclass StringTree2
static <A> void addToStringTree(StringTree2<A> tree, L<S> tokC, A leafValue) {
  if (leafValue == null) ret;
  if (empty(tokC)) { tree.leafValue = leafValue; ret; }
  S s = first(tokC);
  StringTree2 t = tree.getOrAdd(s);
  addToStringTree(t, dropFirst(tokC), leafValue);
}
endif