private void ensureCapacity() {
      LighterASTNode[] old = nodes;
      if (old == null) {
        old = new LighterASTNode[10];
        nodes = old;
      }
      else if (count >= old.length) {
        nodes = Arrays.copyOf(old, count * 3 / 2);
      }
    }
private void ensureCapacity()